Pancreatic cancer is a dismal disease with high incidence and poor survival rates.With the aim to improve overall survival of pancreatic cancer patients,new therapeutic approaches are urgently needed.Protein kinases a...Pancreatic cancer is a dismal disease with high incidence and poor survival rates.With the aim to improve overall survival of pancreatic cancer patients,new therapeutic approaches are urgently needed.Protein kinases are key regulatory players in basically all stages of development,maintaining physiologic functions but also being involved in pathogenic processes.c-Jun N-terminal kinases(JNK)and p38 kinases,representatives of the mitogen-activated protein kinases,as well as the casein kinase 1(CK1)family of protein kinases are important mediators of adequate response to cellular stress following inflammatory and metabolic stressors,DNA damage,and others.In their physiologic roles,they are responsible for the regulation of cell cycle progression,cell proliferation and differentiation,and apoptosis.Dysregulation of the underlying pathways consequently has been identified in various cancer types,including pancreatic cancer.Pharmacological targeting of those pathways has been the field of interest for several years.While success in earlier studies was limited due to lacking specificity and off-target effects,more recent improvements in small molecule inhibitor design against stress-activated protein kinases and their use in combination therapies have shown promising in vitro results.Consequently,targeting of JNK,p38,and CK1 protein kinase family members may actually be of particular interest in the field of precision medicine in patients with highly deregulated kinase pathways related to these kinases.However,further studies are warranted,especially involving in vivo investigation and clinical trials,in order to advance inhibition of stress-activated kinases to the field of translational medicine.展开更多
The mitogen-activated protein kinase(MAPK)cascade is crucial to plant growth,development,and stress responses.MAPK kinases(MAPKK)play a vital role in linking upstream MAPKK kinases(MAPKKK)with the downstream MAPK.Blac...The mitogen-activated protein kinase(MAPK)cascade is crucial to plant growth,development,and stress responses.MAPK kinases(MAPKK)play a vital role in linking upstream MAPKK kinases(MAPKKK)with the downstream MAPK.Black spot is one of the most serious fungal diseases of pear which is an important part of the fruit industry in China.The MAPKK genes have been identified in many plants,however,none has been reported in pear(Pyrus bretschneideri).In order to explore whether MAPK gene of pear is related to black spot disease,we designed this experiment.The present study investigated eight putative PbrMAPKK genes obtained from the Chinese white pear genome.The phylogenetic analysis revealed that PbrMAPKK genes were divided into A,B,C,and D groups.These PbrMAPKK genes are randomly distributed on 7 out of 17 chromosomes and mainly originated from the whole-genome duplication(WGD)event.The expression analysis of PbrMAPKK genes in seven pear tissues and the leaves of susceptible and resistant varieties after Alternaria alternata infection by quantitative real-time PCR(qRT-PCR)identified seven candidate genes associated with resistance.Furthermore,virus-induced gene silencing(VIGS)indicated that PbrMAPKK6 gene enhanced resistance to pear black spot disease in pear.展开更多
AIM To investigate the antioxidant effect of caffeic acid phenethyl ester(CAPE) in hepatic stellate cell-T6(HSC-T6) cells cultured in vitro and the potential mechanisms.METHODS HSC-T6 cells were cultured in vitro and ...AIM To investigate the antioxidant effect of caffeic acid phenethyl ester(CAPE) in hepatic stellate cell-T6(HSC-T6) cells cultured in vitro and the potential mechanisms.METHODS HSC-T6 cells were cultured in vitro and treated with various concentrations of CAPE for 24, 48 and 72 h, respectively. Cell proliferation was investigated using the MTT assay, and cell ultrastructural alterations were observed by transmission electron microscopy. Flow cytometry was employed to investigate the effects of CAPE on apoptosis and the levels of reactive oxygen species in HSC-T6 cells cultured in vitro. An enzyme immunoassay instrument was used to evaluate antioxidant enzyme expression. The effect on α-smooth muscle actin was shown using immunofluorescence. Gene and protein levels of Nrf2, related factors, and mitogen activated protein kinases(MAPKs), in HSC-T6 cells were detected using RT-PCR and Western blot, respectively.RESULTS CAPE inhibited the proliferation and activation of HSC-T6 cells cultured in vitro. CAPE increased the antioxidant levels and the translocation of Nrf2 from the cytoplasm to the nucleus in HSC-T6 cells. Moreover,the phosphorylation of MAPKs in cells decreased in response to CAPE. Interestingly, CAPE-induced oxidative stress in the cells was significantly attenuated by pretreatment with MAPKs inhibitors.CONCLUSION CAPE inhibits cell proliferation and up-regulates the antioxidant levels in HSC-T6 cells partly through the Nrf2-MAPKs signaling pathway.展开更多
Molecularly targeted therapeutic agents are constantly being developed and have been shown to be effective in various clinical trials.One group of representative targeted oncogenic kinases,the receptor tyrosine kinase...Molecularly targeted therapeutic agents are constantly being developed and have been shown to be effective in various clinical trials.One group of representative targeted oncogenic kinases,the receptor tyrosine kinases(RTKs),has been associated with gastric cancer development.Trastuzumab,an inhibitor of ERBB2,has been approved for the treatment of gastric cancer,although other receptor tyrosine kinases,such as epidermal growth factor receptor,vascular endothelial growth factor,platelet-derived growth factor receptor,c-Met,IGF-1R and fibroblast growth factor receptor 2,are also activated in gastric cancer.The promising results of the trastuzumab clinical trial for gastric cancer resulted in the approval of trastuzumab-based therapy as a first-line treatment for human epidermal growth factor receptor 2-positive patients.On the other hand,the trial examining bevacizumab in combination with conventional chemotherapy did not meet its primary goal of increasing the overall survival time of gastric cancer patients;however,a significantly higher response rate and a longer progression-free survival were observed in the bevacizumab arm of the trial.Other clinical trials,especially phaseⅢtrials that have tested drugs targeting RTKs,such as cetuximab,panitumumab,gefitinib,erlotinib,figitumumab,sorafenib,sunitinib and lapatinib,have shown that these drugs have modest effects against gastric cancer.This review summarizes the recent results from the clinical trials of molecularly targeted drugs and suggests that further improvements in the treatment of advanced gastric cancer can be achieved through the combination of conventional drugs with the new molecularly targeted therapies.展开更多
Ras homolog(Rho)-associated kinases(ROCKs)belong to the serine-threonine kinase family,which plays a pivotal role in regulating the damage,survival,axon guidance,and regeneration of neurons.ROCKs are also involved in ...Ras homolog(Rho)-associated kinases(ROCKs)belong to the serine-threonine kinase family,which plays a pivotal role in regulating the damage,survival,axon guidance,and regeneration of neurons.ROCKs are also involved in the biological effects of immune cells and glial cells,as well as the development of neurodegenerative disorders such as Alzheimer’s disease,Parkinson’s disease,and multiple sclerosis.Previous studies by us and others confirmed that ROCKs inhibitors attenuated the symptoms and progression of experimental models of the abovementioned neurodegenerative diseases by inhibiting neuroinflammation,regulating immune imbalance,repairing the blood-brain barrier,and promoting nerve repair and myelin regeneration.Fasudil,the first ROCKs inhibitor to be used clinically,has a good therapeutic effect on neurodegenerative diseases.Fasudil increases the activity of neural stem cells and mesenchymal stem cells,thus optimizing cell therapy.This review will systematically describe,for the first time,the effects of abnormal activation of ROCKs on T cells,B cells,microglia,astrocytes,oligodendrocytes,and pericytes in neurodegenerative diseases of the central nervous system,summarize the therapeutic potential of fasudil in several experimental models of neurodegenerative diseases,and clarify the possible cellular and molecular mechanisms of ROCKs inhibition.This review also proposes that fasudil is a novel potential treatment,especially in combination with cell-based therapy.Findings from this review add support for further investigation of ROCKs and its inhibitor fasudil for the treatment of neurodegenerative diseases.展开更多
P21-activated kinases(PAKs) are central players in various oncogenic signaling pathways. The six PAK family members are classified into group Ⅰ(PAK1-3) and group Ⅱ(PAK4-6). Focus is currently shifting from group Ⅰ ...P21-activated kinases(PAKs) are central players in various oncogenic signaling pathways. The six PAK family members are classified into group Ⅰ(PAK1-3) and group Ⅱ(PAK4-6). Focus is currently shifting from group Ⅰ PAKs to group Ⅱ PAKs. Group Ⅱ PAKs play important roles in many fundamental cellular processes, some of which have particular significance in the development and progression of cancer. Because of their important functions, group Ⅱ PAKs have become popular potential drug target candidates. However, few group Ⅱ PAKs inhibitors have been reported, and most do not exhibit satisfactory kinase selectivity and "drug-like" properties. Isoform- and kinase-selective PAK inhibitors remain to be developed. This review describes the biological activities of group Ⅱ PAKs, the importance of group Ⅱ PAKs in the development and progression of gastrointestinal cancer, and smallmolecule inhibitors of group Ⅱ PAKs for the treatment of cancer.展开更多
Aside from Polo and Aurora, a third but less studied kinase family involved in mitosis regulation is the never in mitosis-gene A(NIMA)-related kinases(Neks). The founding member of this family is the sole member NIMA ...Aside from Polo and Aurora, a third but less studied kinase family involved in mitosis regulation is the never in mitosis-gene A(NIMA)-related kinases(Neks). The founding member of this family is the sole member NIMA of Aspergillus nidulans, which is crucial for the initiation of mitosis in that organism. All 11 human Neks have been functionally assigned to one of the three core functions established for this family in mammals:(1) centrioles/mitosis;(2) primary ciliary function/ciliopathies; and(3) DNA damage response(DDR). Recent findings, especially on Nek 1 and 8, showed however, that several Neks participate in parallel in at least two of these contexts: primary ciliary function and DDR. In the core section of this in-depth review, we report the current detailed functional knowledge on each of the 11 Neks. In the discussion, we return to the cross-connections among Neks and point out how our and other groups' functional and interactomics studies revealed that most Neks interact with protein partners associated with two if not all three of the functional contexts. We then raise the hypothesis that Neks may be the connecting regulatory elements that allow the cell to fine tune and synchronize the cellular events associated with these three core functions. The new and exciting findings on the Nek family open new perspectives and should allow the Neks to finally claim the attention they deserve in the field of kinases and cell cycle biology.展开更多
BACKGROUND:Paraquat(PQ)-induced acute lung injury(ALI)and pulmonary fi brosis are common diseases with high mortality but without eff ective antidotes in emergency medicine.Our previous study has proved that arctigeni...BACKGROUND:Paraquat(PQ)-induced acute lung injury(ALI)and pulmonary fi brosis are common diseases with high mortality but without eff ective antidotes in emergency medicine.Our previous study has proved that arctigenin suppressed pulmonary fibrosis induced by PQ.We wondered whether arctigenin could also have a protective eff ect on PQ-induced ALI.METHODS:A PQ-induced A549 cell injury model was used,and the effect of arctigenin was determined by a cell counting kit-8(CCK-8)cell viability assay.In addition,terminal deoxynucleotidyl transferase(TdT)-mediated dUTP nick-end labelling(TUNEL)staining assays and mitochondrial membrane potential assays were performed to evaluate the level of cell apoptosis.The generation of reactive oxygen species(ROS)was refl ected by dihydroethidium(DHE)staining and a 2’,7’-dichlorodihy drofluorescein diacetate(DCFH-DA)assay.Moreover,immunoblotting studies were used to assess the expression of mitogen-activated protein kinases(MAPKs)and p38 MAPK.RESULTS:Arctigenin attenuated PQ-induced inhibition of A549 cell viability in a dose-dependent manner.Arctigenin also significantly reduced PQ-induced A549 cell apoptosis,as refl ected by the TUNEL assay and mitochondrial membrane potential assay,which may result from suppressed ROS/p38 MAPK signaling because we found that arctigenin dramatically suppressed ROS generation and p38 MAPK phosphorylation.CONCLUSION:Arctigenin could attenuate PQ-induced lung epithelial A549 cell injury in vitro by suppressing ROS/p38 MAPK-mediated cell apoptosis,and arctigenin might be considered a potential candidate drug for PQ-induced ALI.展开更多
Aurora kinases regulate multiple steps of mitotic cell division in eukaryotic cells. Overexpression of aurora kinases has been observed in some tumor cells, which suggests that abnormalities in aurora kinases are clos...Aurora kinases regulate multiple steps of mitotic cell division in eukaryotic cells. Overexpression of aurora kinases has been observed in some tumor cells, which suggests that abnormalities in aurora kinases are closely related to tumorigenesis. In additon, aurora kinases are often amplified or overexpressed in breast cancer cells, leading to chromosomal segregation abnormalities and genomic disorder, and thereby activating oncogenic pathways. Novel Aurora A kinase inhibitors are currently being studied in multiple phase I and II studies. In this review, we describe the biological functions and mechanisms of aurora kinases in breast cancer cells and summarize the preclinical findings related to aurora kinases in breast cancer.展开更多
Protein kinases play an important role in every aspect of cellular life.In this study,we systemically identified protein kinases from the predicted proteomes of 59 representative fungi from Ascomycota and Basidiomycot...Protein kinases play an important role in every aspect of cellular life.In this study,we systemically identified protein kinases from the predicted proteomes of 59 representative fungi from Ascomycota and Basidiomycota.Comparative analysis revealed that fungi from Ascomycota and Basidiomycota differed in the number and variety of protein kinases.Some groups of protein kinases,such as calmodulin/calcium regulated kinases(CMGC) and those with the highest group percentages are the most prevalent protein kinases among all fungal species tested.In contrast,the STE group(homologs of the yeast STE7,STE11 and STE20 genes),was more abundant in Basidiomycetes than in Ascomycetes.Importantly,the distribution of some protein kinase families appeared to be subphylum-specific.The tyrosine kinase-like(TKL) group had a higher protein kinase density in Agaricomycotina fungi.In addition,the distribution of accessory domains,which could have functional implications,demonstrated that usage bias varied between the two phyla.Principal component analysis revealed a divergence between the main functional domains and associated domains in fungi.This study provides novel insights into the variety and expansion of fungal protein kinases between Ascomycota and Basidiomycota.展开更多
Previously, we reported that M-CSF induced monocyte survival through the activation of Akt, p38MAPK and Erk1/2 kinases. Here, we found that Src family kinases were upstream of these kinases and played a central role i...Previously, we reported that M-CSF induced monocyte survival through the activation of Akt, p38MAPK and Erk1/2 kinases. Here, we found that Src family kinases were upstream of these kinases and played a central role in regulating M-CSF-induced monocyte survival. We observed that M-CSF promoted c-Src activation in monocytes and MDMs in a time-dependent manner. Src inhibitors reduced M-CSF-mediated phosphorylation of the M-CSF receptor (M-CSFR), Akt, Erk1/2, and p38 MAPK. We also observed that Src directly phosphorylated the M-CSFR. Notably, the inhibitors blocked phosphorylation of specific tyrosine residues within the M-CSFR. We further demonstrated that the Src inhibitor, PP2, attenuated M-CSF-induced NF-κB activation and M-CSF-induced monocyte survival. These findings indicated that Src family kinases mediate monocyte survival through the regulation of receptor phosphorylation and modulation of downstream signaling events. Thus, we predict that targeting Src family kinases may have therapeutic implication in inflammatory diseases.展开更多
Antiviral drugs currently on the market primarily target proteins encoded by specific viruses. The drawback of these drugs is that they lack antiviral mechanisms that account for resistance or viral mutation. Thus, th...Antiviral drugs currently on the market primarily target proteins encoded by specific viruses. The drawback of these drugs is that they lack antiviral mechanisms that account for resistance or viral mutation. Thus, there is a pressing need for researchers to explore and investigate new therapeutic agents with other antiviral strategies. Viruses such as the human immunodeficiency virus (HIV) alter canonical signaling pathways to create a favorable biochemical environment for infectivity. We used Qiagen Ingenuity Pathway Analysis (IPA) software to review the function of several cellular kinases and the resulting perturbed signaling pathways during HIV infection such as NF-κB signaling. These host cellular kinases such as ADK, PKR, MAP3K11 are involved during HIV infection at various stages of the life cycle. Additionally IPA analysis indicated that these modified host cellular kinases are known to have interactions with each other especially AKT1, a serine/threonine kinase involved in multiple pathways. We present a list of cellular host kinases and other proteins that interact with these kinases. This approach to understanding the relationship between HIV infection and kinase activity may introduce new drug targets to arrest HIV infectivity.展开更多
Oral tyrosine kinase inhibitors(TKIs) against epidermal growth factor receptor(EGFR) family have been introduced into the clinic to treat human malignancies for decades. Despite superior properties of EGFR-TKIs as sma...Oral tyrosine kinase inhibitors(TKIs) against epidermal growth factor receptor(EGFR) family have been introduced into the clinic to treat human malignancies for decades. Despite superior properties of EGFR-TKIs as small molecule targeted drugs, their applications are still restricted due to their low solubility, capricious oral bioavailability, large requirement of daily dose, high binding tendency to plasma albumin and initial/acquired drug resistance. Nanotechnology is a promising tool to improve efficacy of these drugs. Through non-oral routes. Various nanotechnology-based delivery approaches have been developed for providing efficient delivery of EGFR-TKIs with a better pharmacokinetic profile and tissue-targeting ability. This review aims to indicate the advantage of nanocarriers for EGFR-TKIs delivery.展开更多
Objective: To survey the role of protein tyrosine kinases (PTKs) in the pathogenesis of several hematopoietic malignancies. Methods: By reviewing the published laboratory and clinical studies on PTK-related oncoprotei...Objective: To survey the role of protein tyrosine kinases (PTKs) in the pathogenesis of several hematopoietic malignancies. Methods: By reviewing the published laboratory and clinical studies on PTK-related oncoproteins and their causative role in some leukemias and lymphomas. Results: Protein tyrosine kinases are key participants in signal transduction pathways that regulate cellular growth, activation and differentiations. Aberrant PTK activity resulting from gene mutation (often accompanying chromosome translocation) plays an etiologic role in several clonal hematopoietic malignancies. For example, the PTK product of the BCR-ABL fusion gene resulting from the t (9; 22) translocation exhibits several fold higher tyrosine kinase activity than the product of the ABL gene. Evidence suggests that the BCR-ABL oncoprotein alone is sufficient to case chronic myelogenous leukemia (CML) and other Ph positive acute leukemia. PTK over-activity resulting from chromosomal translocations creating TEL-ABL, TEL-JAK2 and TEL-PDGFRb fusion proteins plays an important role in the pathogenesis of other types of leukemia. Another example occurs in anaplastic large cell lymphoma (ALCL). Experimental and clinical evidences indicate that translocations involving ALK gene on chromosome 2p23, most commonly resulting in an NPM-ALK fusion oncogene, result in constitutive activation of ALK and cause ALCL. This group of lymphomas is now named ALK positive lymphoma or ALKoma. Conclusion: Genetic lesions creating aberrant fusion proteins that result in excessive PTK activity are increasingly being recognized as central to the pathogenesis of hemotopoietic malignancies. These chimeric PTK molecules represent attractive disease-specific targets against which new classes therapeutic agents are being developed.展开更多
Pim kinases contribute to tumor formation and development of lymphoma,which shows enhanced DNA replication,DNA recombination and repair.Endothelial cells (ECs) express all the three members of Pim kinase gene family.W...Pim kinases contribute to tumor formation and development of lymphoma,which shows enhanced DNA replication,DNA recombination and repair.Endothelial cells (ECs) express all the three members of Pim kinase gene family.We hypothesized that DNA repair gene would regulate Pim ex-pression in ECs.Human umbilical vein endothelial cells (HUVECs) were isolated and maintained in M199 culture medium.The cellular distribution of Pim-3 in ECs was determined by immunofluorescent staining.The siRNA fragments were synthesized and transfected by using Lipofectamine LTX.The total cellular RNA was extracted from the cells by using Trizol reagent.cDNAs were quantified by semi-quantity PCR.The effects of LY294002 and wortmannin on RNA stability in ECs were also ex-amined.Our data showed that LY294002 and wortmannin,phosphatidylinositol 3-kinase (PI3K) and PI3K-like kinase inhibitors,increased Pim mRNA expression in ECs without altering the mRNA stabil-ity.RNA interference (RNAi) targeting DNA-dependent protein kinase catalytic subunit (DNA-PKcs) and ataxia telangiectasia mutated (ATM) increased mRNA expression of Pim-3 and Pim-1,respectively.Silencing of Akt decreased Pim-1 instead of Pm-2 and Pim-3 gene expression in ECs.But etoposide,a nucleoside analogue,which could activate DNA-PKcs and ATM,increased Pim expression in ECs.Our study indicates that the expression of Pim kinases is physiologically related to DNA-PKcs and ATM in ECs.展开更多
Metabolic syndrome is a pre-diabetic state characterized by several biochemical and physiological alterations,including insulin resistance,visceral fat accumulation,and dyslipidemias,which increase the risk for develo...Metabolic syndrome is a pre-diabetic state characterized by several biochemical and physiological alterations,including insulin resistance,visceral fat accumulation,and dyslipidemias,which increase the risk for developing cardiovascular disease.Metabolic syndrome is associated with augmented sympathetic tone,which could account for the etiology of pre-diabetic cardiomyopathy.This review summarizes the current knowledge of the pathophysiological consequences of enhanced and sustainedβ-adrenergic response in pre-diabetes,focusing on cardiac dysfunction reported in diet-induced experimental models of pre-diabetic cardiomyopathy.The research reviewed indicates that both protein kinase A and Ca^(2+)/calmodulin-dependent protein kinase Ⅱ play important roles in functional responses mediated byβ1-adrenoceptors;therefore,alterations in the expression or function of these kinases can be deleterious.This review also outlines recent information on the role of protein kinase A and Ca^(2+)/calmodulin-dependent protein kinase Ⅱ in abnormal Ca^(2+)handling by cardiomyocytes from diet-induced models of pre-diabetic cardiomyopathy.展开更多
Protein phosphorylation and dephosphorylation are two essential and vital cellular mechanisms that regulate many receptors and enzymes through kinases and phosphatases.Ca^2+- dependent kinases and phosphatases are res...Protein phosphorylation and dephosphorylation are two essential and vital cellular mechanisms that regulate many receptors and enzymes through kinases and phosphatases.Ca^2+- dependent kinases and phosphatases are responsible for controlling neuronal processing;balance is achieved through opposition.During molecular mechanisms of learning and memory,kinases generally modulate positively while phosphatases modulate negatively.This review outlines some of the critical physiological and structural aspects of kinases and phosphatases involved in maintaining postsynaptic structural plasticity.It also explores the link between neuronal disorders and the deregulation of phosphatases and kinases.展开更多
We screened 95 kinase inhibitors whether they affect cAMP-dependent proteolysis of GATA-6 or not. Among them 7 inhibitors inhibited the proteolysis at the concentration range of μM around their IC50. They are inhibit...We screened 95 kinase inhibitors whether they affect cAMP-dependent proteolysis of GATA-6 or not. Among them 7 inhibitors inhibited the proteolysis at the concentration range of μM around their IC50. They are inhibitors for protein kinase A (H-89 and 4- cyano-3-methylisoquinoline), c-Jun N-terminal kinase (SP600125), phosphatidylinositol 3-kinase (Wort- mannin and LY-294002), casein kinase II (TBB) and cyclin dependent kinase (Cdk1/2 inhibitor III). It is of interest how these kinases play roles in the degradation process of GATA-6 since this transcription factor is essential for development and tissue-specific gene expression of mammals. Inhibitors identified in this study would be helpful to study molecular mechanisms of phenomena in which GATA-6 participates.展开更多
Sphingolipids are ubiquitous components of cell membranes. Their metabolites ceramide, sphingosine, and sphingosine-1-phosphate (S1P) have important physiological functions, including regulation of cell growth and sur...Sphingolipids are ubiquitous components of cell membranes. Their metabolites ceramide, sphingosine, and sphingosine-1-phosphate (S1P) have important physiological functions, including regulation of cell growth and survival. S1P is generated by phosphorylation of sphingosine catalyzed by sphingosine kinase-1 (SPHK1). The purpose of this study is to explore the roles of S1P, S1P receptors, and sphingosine kinases in malignant musculoskeletal tumors. Twenty-one tumor samples (7 liposarcomas, 3 chondrosarcomas, 6 osteosarcomas, 5 MFH) obtained at open biopsy, and four human MFH cell lines (Nara H, Nara F, TNMY1, GBS-1) were used. We examined the mRNA expression of S1P receptors by RT-PCR, and the expression levels of SPHK by Real-time PCR. We used 4 MFH cell lines to analyze SPHK1 proteins by Western blotting. SPHK1 siRNA was transfected into MFH cell lines by lipofection method. Cell proliferation (control and transfected with siRNA) was assayed using WST-8 (Cell Counting Kit-8) assay. All high grade malignant tumors expressed S1P1, S1P2, S1P3 receptors, whereas the expression of S1P1 receptor was detected in 50% of low-grade malignant tumors, S1P2 receptor in 30%, and S1P3 in 50%. No statistically significant difference was found in the expression level of SPHK1 between high-grade and low-grade malignant tumors by Real-time PCR. By results of Western blotting, proteins of SPHK1 were expressed in all MFH cell lines. In MFH cell lines, transfection with SPHK1 siRNA oligonucleotides resulted in approximately 50 to 80% suppression of SPHK1 mRNA expression as determined by real-time PCR. Down-regulation of SPHK1 with small interfering RNA significantly reduced SPHK1 protein levels by Western blotting. Knock down of SPHK1 expression significantly decreased cell proliferation of all MFH cells. These results suggest that the expression of S1P receptors may play an important role for cell proliferation and may correlate with histologic grade in malignant bone and soft tissue tumors, and that SPHK1 may be one of essential molecules for cell proliferation in MFH cell lines.展开更多
Recent Background: Development of obesity involves promotion of preadipocyte differrentiation. This study investigated the role that sphingosine kinases (SPHK) and ceramide-derived sphingosine 1-phosphate (S1P) play i...Recent Background: Development of obesity involves promotion of preadipocyte differrentiation. This study investigated the role that sphingosine kinases (SPHK) and ceramide-derived sphingosine 1-phosphate (S1P) play in adipocyte terminal differentiation. Materials and Methods: The mouse 3T3-L1 cell line was used as a model for adipogenesis. Cells were harvested at specific time points after initation of differentiation, and SPHK activity was measured. 3T3-L1 cells were treated with S1P and expression of early adipogenesis transcription markers was measured by real time PCR. The expression of S1P-receptors (S1PRs) during differentiation was measured. Results: SPHK activity is induced when 3T3-L1 cells are treated with insulin, dexamethasone, and isobutylmethylxanthine to induce differentiation. SPHK1 is active in preadipocytes and early in the differentiation process. Both SPHK1 and SPHK2 isozymes contribute to activity in differentiated adipocytes. Inhibition of SPHK1 attenuates adipocyte differentiation;however, extracellular S1P does not rescue the effect of SPHK1 inhibition on adipogenesis. Although treatment of preadipocytes with S1P induced message expression of the early adipogenesis transcription factor CC AAT/ binding proteinalpha, continued treatment did not fully support the development of differentiated adipocytes. Sphingosine 1-phosphate receptors (S1PRs) are expressed in preadipocytes and message expression declines markedly during adipocyte differentiation. Conclusion: These results demonstrate that the contribution of SPHK and S1P to adipogenesis is mediated primarily through biphasic activation of SPHK1 and 2 with extracellular S1P and S1PRs playing little role during preadipocyte differentiation.展开更多
基金German Research Foundation(DFG),No.TR1663/1-1 and No.KN356/9-1and Else Kröner-Fresenius-Stiftung,No.2017_A142.
文摘Pancreatic cancer is a dismal disease with high incidence and poor survival rates.With the aim to improve overall survival of pancreatic cancer patients,new therapeutic approaches are urgently needed.Protein kinases are key regulatory players in basically all stages of development,maintaining physiologic functions but also being involved in pathogenic processes.c-Jun N-terminal kinases(JNK)and p38 kinases,representatives of the mitogen-activated protein kinases,as well as the casein kinase 1(CK1)family of protein kinases are important mediators of adequate response to cellular stress following inflammatory and metabolic stressors,DNA damage,and others.In their physiologic roles,they are responsible for the regulation of cell cycle progression,cell proliferation and differentiation,and apoptosis.Dysregulation of the underlying pathways consequently has been identified in various cancer types,including pancreatic cancer.Pharmacological targeting of those pathways has been the field of interest for several years.While success in earlier studies was limited due to lacking specificity and off-target effects,more recent improvements in small molecule inhibitor design against stress-activated protein kinases and their use in combination therapies have shown promising in vitro results.Consequently,targeting of JNK,p38,and CK1 protein kinase family members may actually be of particular interest in the field of precision medicine in patients with highly deregulated kinase pathways related to these kinases.However,further studies are warranted,especially involving in vivo investigation and clinical trials,in order to advance inhibition of stress-activated kinases to the field of translational medicine.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFD1200503)Jiangsu Agriculture Science and Technology Innovation Fund[Grant Nos.SCX(22)3215],Fundamental Research Funds for the Central Universities(Grant No.JCQY201901)the Earmarked Fund for China Agriculture Research System(Grant No.CARS-28).
文摘The mitogen-activated protein kinase(MAPK)cascade is crucial to plant growth,development,and stress responses.MAPK kinases(MAPKK)play a vital role in linking upstream MAPKK kinases(MAPKKK)with the downstream MAPK.Black spot is one of the most serious fungal diseases of pear which is an important part of the fruit industry in China.The MAPKK genes have been identified in many plants,however,none has been reported in pear(Pyrus bretschneideri).In order to explore whether MAPK gene of pear is related to black spot disease,we designed this experiment.The present study investigated eight putative PbrMAPKK genes obtained from the Chinese white pear genome.The phylogenetic analysis revealed that PbrMAPKK genes were divided into A,B,C,and D groups.These PbrMAPKK genes are randomly distributed on 7 out of 17 chromosomes and mainly originated from the whole-genome duplication(WGD)event.The expression analysis of PbrMAPKK genes in seven pear tissues and the leaves of susceptible and resistant varieties after Alternaria alternata infection by quantitative real-time PCR(qRT-PCR)identified seven candidate genes associated with resistance.Furthermore,virus-induced gene silencing(VIGS)indicated that PbrMAPKK6 gene enhanced resistance to pear black spot disease in pear.
基金Supported by the Liver Fibrosis Foundation of Wang BaoEn of China,No.20100033the Science and Technology Foundation of Shaanxi Province of China,No.2010K01-199
文摘AIM To investigate the antioxidant effect of caffeic acid phenethyl ester(CAPE) in hepatic stellate cell-T6(HSC-T6) cells cultured in vitro and the potential mechanisms.METHODS HSC-T6 cells were cultured in vitro and treated with various concentrations of CAPE for 24, 48 and 72 h, respectively. Cell proliferation was investigated using the MTT assay, and cell ultrastructural alterations were observed by transmission electron microscopy. Flow cytometry was employed to investigate the effects of CAPE on apoptosis and the levels of reactive oxygen species in HSC-T6 cells cultured in vitro. An enzyme immunoassay instrument was used to evaluate antioxidant enzyme expression. The effect on α-smooth muscle actin was shown using immunofluorescence. Gene and protein levels of Nrf2, related factors, and mitogen activated protein kinases(MAPKs), in HSC-T6 cells were detected using RT-PCR and Western blot, respectively.RESULTS CAPE inhibited the proliferation and activation of HSC-T6 cells cultured in vitro. CAPE increased the antioxidant levels and the translocation of Nrf2 from the cytoplasm to the nucleus in HSC-T6 cells. Moreover,the phosphorylation of MAPKs in cells decreased in response to CAPE. Interestingly, CAPE-induced oxidative stress in the cells was significantly attenuated by pretreatment with MAPKs inhibitors.CONCLUSION CAPE inhibits cell proliferation and up-regulates the antioxidant levels in HSC-T6 cells partly through the Nrf2-MAPKs signaling pathway.
基金Supported by Grant-in-Aid for Scientific Research(C)from the Ministry of Education,Culture,Sports,Science and Technology of Japan to Masaki T,No.25460998
文摘Molecularly targeted therapeutic agents are constantly being developed and have been shown to be effective in various clinical trials.One group of representative targeted oncogenic kinases,the receptor tyrosine kinases(RTKs),has been associated with gastric cancer development.Trastuzumab,an inhibitor of ERBB2,has been approved for the treatment of gastric cancer,although other receptor tyrosine kinases,such as epidermal growth factor receptor,vascular endothelial growth factor,platelet-derived growth factor receptor,c-Met,IGF-1R and fibroblast growth factor receptor 2,are also activated in gastric cancer.The promising results of the trastuzumab clinical trial for gastric cancer resulted in the approval of trastuzumab-based therapy as a first-line treatment for human epidermal growth factor receptor 2-positive patients.On the other hand,the trial examining bevacizumab in combination with conventional chemotherapy did not meet its primary goal of increasing the overall survival time of gastric cancer patients;however,a significantly higher response rate and a longer progression-free survival were observed in the bevacizumab arm of the trial.Other clinical trials,especially phaseⅢtrials that have tested drugs targeting RTKs,such as cetuximab,panitumumab,gefitinib,erlotinib,figitumumab,sorafenib,sunitinib and lapatinib,have shown that these drugs have modest effects against gastric cancer.This review summarizes the recent results from the clinical trials of molecularly targeted drugs and suggests that further improvements in the treatment of advanced gastric cancer can be achieved through the combination of conventional drugs with the new molecularly targeted therapies.
基金supported by the National Natural Science Foundation of China, Nos.81473577 (to CGM), 81903596 (to QW), 82004028 (to LJS)China Postdoctoral Science Foundation, No.2020M680912 (to LJS)+2 种基金Open Project of The Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry, The Ministry of Education of China,No.2019004 (to CGM)Science and Technology Innovation Project of Shanxi Colleges of China, Nos.2019L0728 (to QW)Cultivation Project of Shanxi Universtity of Chinese Medicine of China, No.2019PY130 (to QW)
文摘Ras homolog(Rho)-associated kinases(ROCKs)belong to the serine-threonine kinase family,which plays a pivotal role in regulating the damage,survival,axon guidance,and regeneration of neurons.ROCKs are also involved in the biological effects of immune cells and glial cells,as well as the development of neurodegenerative disorders such as Alzheimer’s disease,Parkinson’s disease,and multiple sclerosis.Previous studies by us and others confirmed that ROCKs inhibitors attenuated the symptoms and progression of experimental models of the abovementioned neurodegenerative diseases by inhibiting neuroinflammation,regulating immune imbalance,repairing the blood-brain barrier,and promoting nerve repair and myelin regeneration.Fasudil,the first ROCKs inhibitor to be used clinically,has a good therapeutic effect on neurodegenerative diseases.Fasudil increases the activity of neural stem cells and mesenchymal stem cells,thus optimizing cell therapy.This review will systematically describe,for the first time,the effects of abnormal activation of ROCKs on T cells,B cells,microglia,astrocytes,oligodendrocytes,and pericytes in neurodegenerative diseases of the central nervous system,summarize the therapeutic potential of fasudil in several experimental models of neurodegenerative diseases,and clarify the possible cellular and molecular mechanisms of ROCKs inhibition.This review also proposes that fasudil is a novel potential treatment,especially in combination with cell-based therapy.Findings from this review add support for further investigation of ROCKs and its inhibitor fasudil for the treatment of neurodegenerative diseases.
基金Supported by National Natural Science Foundation of ChinaNo.90813038+2 种基金No.31271389No.31371424No.31171360 and No.81230077
文摘P21-activated kinases(PAKs) are central players in various oncogenic signaling pathways. The six PAK family members are classified into group Ⅰ(PAK1-3) and group Ⅱ(PAK4-6). Focus is currently shifting from group Ⅰ PAKs to group Ⅱ PAKs. Group Ⅱ PAKs play important roles in many fundamental cellular processes, some of which have particular significance in the development and progression of cancer. Because of their important functions, group Ⅱ PAKs have become popular potential drug target candidates. However, few group Ⅱ PAKs inhibitors have been reported, and most do not exhibit satisfactory kinase selectivity and "drug-like" properties. Isoform- and kinase-selective PAK inhibitors remain to be developed. This review describes the biological activities of group Ⅱ PAKs, the importance of group Ⅱ PAKs in the development and progression of gastrointestinal cancer, and smallmolecule inhibitors of group Ⅱ PAKs for the treatment of cancer.
基金Supported by Fundao de AmparoàPesquisa do Estado S o Paulo(FAPESP,Grant No.2010/51730-0)Conselho Nacional de Pesquisa e Desenvolvimento(CNPq)Centro Nacional de Pesquisa em Energia e Materiais(CNPEM)
文摘Aside from Polo and Aurora, a third but less studied kinase family involved in mitosis regulation is the never in mitosis-gene A(NIMA)-related kinases(Neks). The founding member of this family is the sole member NIMA of Aspergillus nidulans, which is crucial for the initiation of mitosis in that organism. All 11 human Neks have been functionally assigned to one of the three core functions established for this family in mammals:(1) centrioles/mitosis;(2) primary ciliary function/ciliopathies; and(3) DNA damage response(DDR). Recent findings, especially on Nek 1 and 8, showed however, that several Neks participate in parallel in at least two of these contexts: primary ciliary function and DDR. In the core section of this in-depth review, we report the current detailed functional knowledge on each of the 11 Neks. In the discussion, we return to the cross-connections among Neks and point out how our and other groups' functional and interactomics studies revealed that most Neks interact with protein partners associated with two if not all three of the functional contexts. We then raise the hypothesis that Neks may be the connecting regulatory elements that allow the cell to fine tune and synchronize the cellular events associated with these three core functions. The new and exciting findings on the Nek family open new perspectives and should allow the Neks to finally claim the attention they deserve in the field of kinases and cell cycle biology.
基金This work was supported by the National Natural Science Foundation of China(82172182 and 82102311)Social Development Projects of Jiangsu Province(BE2017720)+2 种基金Natural Science Foundation of Jiangsu Province(BK20190247)Science Foundation of Jiangsu Health Commission(H2018039)Jiangsu Postdoctoral Research Foundation(2018K048A and 2020Z193).
文摘BACKGROUND:Paraquat(PQ)-induced acute lung injury(ALI)and pulmonary fi brosis are common diseases with high mortality but without eff ective antidotes in emergency medicine.Our previous study has proved that arctigenin suppressed pulmonary fibrosis induced by PQ.We wondered whether arctigenin could also have a protective eff ect on PQ-induced ALI.METHODS:A PQ-induced A549 cell injury model was used,and the effect of arctigenin was determined by a cell counting kit-8(CCK-8)cell viability assay.In addition,terminal deoxynucleotidyl transferase(TdT)-mediated dUTP nick-end labelling(TUNEL)staining assays and mitochondrial membrane potential assays were performed to evaluate the level of cell apoptosis.The generation of reactive oxygen species(ROS)was refl ected by dihydroethidium(DHE)staining and a 2’,7’-dichlorodihy drofluorescein diacetate(DCFH-DA)assay.Moreover,immunoblotting studies were used to assess the expression of mitogen-activated protein kinases(MAPKs)and p38 MAPK.RESULTS:Arctigenin attenuated PQ-induced inhibition of A549 cell viability in a dose-dependent manner.Arctigenin also significantly reduced PQ-induced A549 cell apoptosis,as refl ected by the TUNEL assay and mitochondrial membrane potential assay,which may result from suppressed ROS/p38 MAPK signaling because we found that arctigenin dramatically suppressed ROS generation and p38 MAPK phosphorylation.CONCLUSION:Arctigenin could attenuate PQ-induced lung epithelial A549 cell injury in vitro by suppressing ROS/p38 MAPK-mediated cell apoptosis,and arctigenin might be considered a potential candidate drug for PQ-induced ALI.
文摘Aurora kinases regulate multiple steps of mitotic cell division in eukaryotic cells. Overexpression of aurora kinases has been observed in some tumor cells, which suggests that abnormalities in aurora kinases are closely related to tumorigenesis. In additon, aurora kinases are often amplified or overexpressed in breast cancer cells, leading to chromosomal segregation abnormalities and genomic disorder, and thereby activating oncogenic pathways. Novel Aurora A kinase inhibitors are currently being studied in multiple phase I and II studies. In this review, we describe the biological functions and mechanisms of aurora kinases in breast cancer cells and summarize the preclinical findings related to aurora kinases in breast cancer.
基金supported by the National Science & Technology Pillar Program of China during the Twelfth Five-Year Plan period (2012BAD19B04)the National Natural Science Foundation of China (31371924)+1 种基金the 111 Project from the Ministry of Education of China (B07049)the National Basic Research Program of China (2013CB127700)
文摘Protein kinases play an important role in every aspect of cellular life.In this study,we systemically identified protein kinases from the predicted proteomes of 59 representative fungi from Ascomycota and Basidiomycota.Comparative analysis revealed that fungi from Ascomycota and Basidiomycota differed in the number and variety of protein kinases.Some groups of protein kinases,such as calmodulin/calcium regulated kinases(CMGC) and those with the highest group percentages are the most prevalent protein kinases among all fungal species tested.In contrast,the STE group(homologs of the yeast STE7,STE11 and STE20 genes),was more abundant in Basidiomycetes than in Ascomycetes.Importantly,the distribution of some protein kinase families appeared to be subphylum-specific.The tyrosine kinase-like(TKL) group had a higher protein kinase density in Agaricomycotina fungi.In addition,the distribution of accessory domains,which could have functional implications,demonstrated that usage bias varied between the two phyla.Principal component analysis revealed a divergence between the main functional domains and associated domains in fungi.This study provides novel insights into the variety and expansion of fungal protein kinases between Ascomycota and Basidiomycota.
文摘Previously, we reported that M-CSF induced monocyte survival through the activation of Akt, p38MAPK and Erk1/2 kinases. Here, we found that Src family kinases were upstream of these kinases and played a central role in regulating M-CSF-induced monocyte survival. We observed that M-CSF promoted c-Src activation in monocytes and MDMs in a time-dependent manner. Src inhibitors reduced M-CSF-mediated phosphorylation of the M-CSF receptor (M-CSFR), Akt, Erk1/2, and p38 MAPK. We also observed that Src directly phosphorylated the M-CSFR. Notably, the inhibitors blocked phosphorylation of specific tyrosine residues within the M-CSFR. We further demonstrated that the Src inhibitor, PP2, attenuated M-CSF-induced NF-κB activation and M-CSF-induced monocyte survival. These findings indicated that Src family kinases mediate monocyte survival through the regulation of receptor phosphorylation and modulation of downstream signaling events. Thus, we predict that targeting Src family kinases may have therapeutic implication in inflammatory diseases.
文摘Antiviral drugs currently on the market primarily target proteins encoded by specific viruses. The drawback of these drugs is that they lack antiviral mechanisms that account for resistance or viral mutation. Thus, there is a pressing need for researchers to explore and investigate new therapeutic agents with other antiviral strategies. Viruses such as the human immunodeficiency virus (HIV) alter canonical signaling pathways to create a favorable biochemical environment for infectivity. We used Qiagen Ingenuity Pathway Analysis (IPA) software to review the function of several cellular kinases and the resulting perturbed signaling pathways during HIV infection such as NF-κB signaling. These host cellular kinases such as ADK, PKR, MAP3K11 are involved during HIV infection at various stages of the life cycle. Additionally IPA analysis indicated that these modified host cellular kinases are known to have interactions with each other especially AKT1, a serine/threonine kinase involved in multiple pathways. We present a list of cellular host kinases and other proteins that interact with these kinases. This approach to understanding the relationship between HIV infection and kinase activity may introduce new drug targets to arrest HIV infectivity.
基金financially supported by the National Natural Science Foundation (31525009 and 31771096)The National Key Research and Development Program of China (2017YFC1103502)+2 种基金Sichuan Innovative Research Team Program for Young Scientists (2016TD0004)Distinguished Young Scholars of Sichuan University (2011SCU04B18)1·3·5 project for disciplines of excellence, West China Hospital, Sichuan University.
文摘Oral tyrosine kinase inhibitors(TKIs) against epidermal growth factor receptor(EGFR) family have been introduced into the clinic to treat human malignancies for decades. Despite superior properties of EGFR-TKIs as small molecule targeted drugs, their applications are still restricted due to their low solubility, capricious oral bioavailability, large requirement of daily dose, high binding tendency to plasma albumin and initial/acquired drug resistance. Nanotechnology is a promising tool to improve efficacy of these drugs. Through non-oral routes. Various nanotechnology-based delivery approaches have been developed for providing efficient delivery of EGFR-TKIs with a better pharmacokinetic profile and tissue-targeting ability. This review aims to indicate the advantage of nanocarriers for EGFR-TKIs delivery.
基金This work was partially supported by a grant from World Health Organization Fellowship (XS) (WPRO AWARD No. 0008/99).
文摘Objective: To survey the role of protein tyrosine kinases (PTKs) in the pathogenesis of several hematopoietic malignancies. Methods: By reviewing the published laboratory and clinical studies on PTK-related oncoproteins and their causative role in some leukemias and lymphomas. Results: Protein tyrosine kinases are key participants in signal transduction pathways that regulate cellular growth, activation and differentiations. Aberrant PTK activity resulting from gene mutation (often accompanying chromosome translocation) plays an etiologic role in several clonal hematopoietic malignancies. For example, the PTK product of the BCR-ABL fusion gene resulting from the t (9; 22) translocation exhibits several fold higher tyrosine kinase activity than the product of the ABL gene. Evidence suggests that the BCR-ABL oncoprotein alone is sufficient to case chronic myelogenous leukemia (CML) and other Ph positive acute leukemia. PTK over-activity resulting from chromosomal translocations creating TEL-ABL, TEL-JAK2 and TEL-PDGFRb fusion proteins plays an important role in the pathogenesis of other types of leukemia. Another example occurs in anaplastic large cell lymphoma (ALCL). Experimental and clinical evidences indicate that translocations involving ALK gene on chromosome 2p23, most commonly resulting in an NPM-ALK fusion oncogene, result in constitutive activation of ALK and cause ALCL. This group of lymphomas is now named ALK positive lymphoma or ALKoma. Conclusion: Genetic lesions creating aberrant fusion proteins that result in excessive PTK activity are increasingly being recognized as central to the pathogenesis of hemotopoietic malignancies. These chimeric PTK molecules represent attractive disease-specific targets against which new classes therapeutic agents are being developed.
基金supported by grants from the National Natural Science Foundation of China (No. 30900631)Hubei Provincial Department of Education (No. Q20102101 andD20082406)
文摘Pim kinases contribute to tumor formation and development of lymphoma,which shows enhanced DNA replication,DNA recombination and repair.Endothelial cells (ECs) express all the three members of Pim kinase gene family.We hypothesized that DNA repair gene would regulate Pim ex-pression in ECs.Human umbilical vein endothelial cells (HUVECs) were isolated and maintained in M199 culture medium.The cellular distribution of Pim-3 in ECs was determined by immunofluorescent staining.The siRNA fragments were synthesized and transfected by using Lipofectamine LTX.The total cellular RNA was extracted from the cells by using Trizol reagent.cDNAs were quantified by semi-quantity PCR.The effects of LY294002 and wortmannin on RNA stability in ECs were also ex-amined.Our data showed that LY294002 and wortmannin,phosphatidylinositol 3-kinase (PI3K) and PI3K-like kinase inhibitors,increased Pim mRNA expression in ECs without altering the mRNA stabil-ity.RNA interference (RNAi) targeting DNA-dependent protein kinase catalytic subunit (DNA-PKcs) and ataxia telangiectasia mutated (ATM) increased mRNA expression of Pim-3 and Pim-1,respectively.Silencing of Akt decreased Pim-1 instead of Pm-2 and Pim-3 gene expression in ECs.But etoposide,a nucleoside analogue,which could activate DNA-PKcs and ATM,increased Pim expression in ECs.Our study indicates that the expression of Pim kinases is physiologically related to DNA-PKcs and ATM in ECs.
文摘Metabolic syndrome is a pre-diabetic state characterized by several biochemical and physiological alterations,including insulin resistance,visceral fat accumulation,and dyslipidemias,which increase the risk for developing cardiovascular disease.Metabolic syndrome is associated with augmented sympathetic tone,which could account for the etiology of pre-diabetic cardiomyopathy.This review summarizes the current knowledge of the pathophysiological consequences of enhanced and sustainedβ-adrenergic response in pre-diabetes,focusing on cardiac dysfunction reported in diet-induced experimental models of pre-diabetic cardiomyopathy.The research reviewed indicates that both protein kinase A and Ca^(2+)/calmodulin-dependent protein kinase Ⅱ play important roles in functional responses mediated byβ1-adrenoceptors;therefore,alterations in the expression or function of these kinases can be deleterious.This review also outlines recent information on the role of protein kinase A and Ca^(2+)/calmodulin-dependent protein kinase Ⅱ in abnormal Ca^(2+)handling by cardiomyocytes from diet-induced models of pre-diabetic cardiomyopathy.
文摘Protein phosphorylation and dephosphorylation are two essential and vital cellular mechanisms that regulate many receptors and enzymes through kinases and phosphatases.Ca^2+- dependent kinases and phosphatases are responsible for controlling neuronal processing;balance is achieved through opposition.During molecular mechanisms of learning and memory,kinases generally modulate positively while phosphatases modulate negatively.This review outlines some of the critical physiological and structural aspects of kinases and phosphatases involved in maintaining postsynaptic structural plasticity.It also explores the link between neuronal disorders and the deregulation of phosphatases and kinases.
文摘We screened 95 kinase inhibitors whether they affect cAMP-dependent proteolysis of GATA-6 or not. Among them 7 inhibitors inhibited the proteolysis at the concentration range of μM around their IC50. They are inhibitors for protein kinase A (H-89 and 4- cyano-3-methylisoquinoline), c-Jun N-terminal kinase (SP600125), phosphatidylinositol 3-kinase (Wort- mannin and LY-294002), casein kinase II (TBB) and cyclin dependent kinase (Cdk1/2 inhibitor III). It is of interest how these kinases play roles in the degradation process of GATA-6 since this transcription factor is essential for development and tissue-specific gene expression of mammals. Inhibitors identified in this study would be helpful to study molecular mechanisms of phenomena in which GATA-6 participates.
文摘Sphingolipids are ubiquitous components of cell membranes. Their metabolites ceramide, sphingosine, and sphingosine-1-phosphate (S1P) have important physiological functions, including regulation of cell growth and survival. S1P is generated by phosphorylation of sphingosine catalyzed by sphingosine kinase-1 (SPHK1). The purpose of this study is to explore the roles of S1P, S1P receptors, and sphingosine kinases in malignant musculoskeletal tumors. Twenty-one tumor samples (7 liposarcomas, 3 chondrosarcomas, 6 osteosarcomas, 5 MFH) obtained at open biopsy, and four human MFH cell lines (Nara H, Nara F, TNMY1, GBS-1) were used. We examined the mRNA expression of S1P receptors by RT-PCR, and the expression levels of SPHK by Real-time PCR. We used 4 MFH cell lines to analyze SPHK1 proteins by Western blotting. SPHK1 siRNA was transfected into MFH cell lines by lipofection method. Cell proliferation (control and transfected with siRNA) was assayed using WST-8 (Cell Counting Kit-8) assay. All high grade malignant tumors expressed S1P1, S1P2, S1P3 receptors, whereas the expression of S1P1 receptor was detected in 50% of low-grade malignant tumors, S1P2 receptor in 30%, and S1P3 in 50%. No statistically significant difference was found in the expression level of SPHK1 between high-grade and low-grade malignant tumors by Real-time PCR. By results of Western blotting, proteins of SPHK1 were expressed in all MFH cell lines. In MFH cell lines, transfection with SPHK1 siRNA oligonucleotides resulted in approximately 50 to 80% suppression of SPHK1 mRNA expression as determined by real-time PCR. Down-regulation of SPHK1 with small interfering RNA significantly reduced SPHK1 protein levels by Western blotting. Knock down of SPHK1 expression significantly decreased cell proliferation of all MFH cells. These results suggest that the expression of S1P receptors may play an important role for cell proliferation and may correlate with histologic grade in malignant bone and soft tissue tumors, and that SPHK1 may be one of essential molecules for cell proliferation in MFH cell lines.
文摘Recent Background: Development of obesity involves promotion of preadipocyte differrentiation. This study investigated the role that sphingosine kinases (SPHK) and ceramide-derived sphingosine 1-phosphate (S1P) play in adipocyte terminal differentiation. Materials and Methods: The mouse 3T3-L1 cell line was used as a model for adipogenesis. Cells were harvested at specific time points after initation of differentiation, and SPHK activity was measured. 3T3-L1 cells were treated with S1P and expression of early adipogenesis transcription markers was measured by real time PCR. The expression of S1P-receptors (S1PRs) during differentiation was measured. Results: SPHK activity is induced when 3T3-L1 cells are treated with insulin, dexamethasone, and isobutylmethylxanthine to induce differentiation. SPHK1 is active in preadipocytes and early in the differentiation process. Both SPHK1 and SPHK2 isozymes contribute to activity in differentiated adipocytes. Inhibition of SPHK1 attenuates adipocyte differentiation;however, extracellular S1P does not rescue the effect of SPHK1 inhibition on adipogenesis. Although treatment of preadipocytes with S1P induced message expression of the early adipogenesis transcription factor CC AAT/ binding proteinalpha, continued treatment did not fully support the development of differentiated adipocytes. Sphingosine 1-phosphate receptors (S1PRs) are expressed in preadipocytes and message expression declines markedly during adipocyte differentiation. Conclusion: These results demonstrate that the contribution of SPHK and S1P to adipogenesis is mediated primarily through biphasic activation of SPHK1 and 2 with extracellular S1P and S1PRs playing little role during preadipocyte differentiation.
