Regulation of intracellular calcium is an important signaling mechanism for cell proliferation in both normal and cancerous cells. In normal epithelial cells, free calcium concentration is essential for cells to enter...Regulation of intracellular calcium is an important signaling mechanism for cell proliferation in both normal and cancerous cells. In normal epithelial cells, free calcium concentration is essential for cells to enter and accomplish the S phase and the M phase of the cell cycle. In contrast, cancerous cells can pass these phases of the cell cycle with much lower cytoplasmic free calcium concentrations, indicating an alternative mechanism has developed for fulfilling the intracellular calcium requirement for an increased rate of DNA synthesis and mitosis of fast replicating cancerous cells. The detailed mechanism underlying the altered calcium loading pathway remains unclear; however, there is a growing body of evidence that suggests the T-type Ca2+ channel is abnormally expressed in cancerous cells and that blockade of these channels may reduce cell proliferation in addition to inducing apoptosis. Recent studies also show that the expression of T-type Ca2+ channels in breast cancer cells is proliferation state dependent, i.e. the channels are expressed at higher levels during the fast-replication period, and once the cells are in a non-proliferation state, expression of this channel isminimal. Therefore, selectively blocking calcium entry into cancerous cells may be a valuable approach for preventing tumor growth. Since T-type Ca2+ channels are not expressed in epithelial cells, selective T-type Ca2+ channel blockers may be useful in the treatment of certain types of cancers.展开更多
Human neuroblastoma cells (SH-SY5Y) have similar structures and functions as neural cells and have been frequently used for cell culture studies of neural cell functions.Previous studies have revealed L-and N-type cal...Human neuroblastoma cells (SH-SY5Y) have similar structures and functions as neural cells and have been frequently used for cell culture studies of neural cell functions.Previous studies have revealed L-and N-type calcium channels in SH-SY5Y cells.However,the distribution of the low-voltage activated calcium channel (namely called T-type calcium channel,including Cav3.1,Cav3.2,and Cav3.3) in SH-SY5Y cells remains poorly understood.The present study detected mRNA and protein expres-sion of the T-type calcium channel (Cav3.1,Cav3.2,and Cav3.3) in cultured SH-SY5Y cells using real-time polymerase chain reaction (PCR) and western blot analysis.Results revealed mRNA and protein expression from all three T-type calcium channel subtypes in SH-SY5Y cells.Moreover,Cav3.1 was the predominant T-type calcium channel subtype in SH-SY5Y cells.展开更多
In the current study,we sought to investigate whether T-type Ca^(2+)channels(TCCs)in the brain are involved in generating post-anesthetic hyperexcitatory behaviors(PAHBs).We found that younger rat pups(postnatal days ...In the current study,we sought to investigate whether T-type Ca^(2+)channels(TCCs)in the brain are involved in generating post-anesthetic hyperexcitatory behaviors(PAHBs).We found that younger rat pups(postnatal days 9-11)had a higher incidence of PAHBs and higher PAHB scores than older pups(postnatal days16-18)during emergence from sevoflurane anesthesia.The power spectrum of the theta oscillations(4 Hz-8 Hz)in the prefrontal cortex was significantly enhanced in younger pups when PAHBs occurred,while there were no significant changes in older pups.Both the power of theta oscillations and the level of PAHBs were significantly reduced by the administration of TCC inhibitors.Moreover,the sensitivity of TCCs in the medial dorsal thalamic nucleus to sevoflurane was found to increase with age by investigating the kinetic properties of TCCs in vitro.TCCs were activated by potentiated GABAergic depolarization with a sub-anesthetic dose of sevoflurane(1%).These data suggest that(1)TCCs in the brain contribute to the generation of PAHBs and the concomitant electroencephalographic changes;(2)the stronger inhibitory effect of sevoflurane contributes to the lack of PAHBs in older rats;and(3)the contribution of TCCs to PAHBs is not mediated by a direct effect of sevoflurane on TCCs.展开更多
Aim:Chemoresistance is a prevalent issue in cancer treatment.Paclitaxel(PTX)is a microtubule-binding anticancer drug used in various cancer treatments.However,cancer cells often show chemoresistance against PTX with t...Aim:Chemoresistance is a prevalent issue in cancer treatment.Paclitaxel(PTX)is a microtubule-binding anticancer drug used in various cancer treatments.However,cancer cells often show chemoresistance against PTX with the help of P-glycoprotein(Pgp)-a drug efflux pump.It has also been observed that overexpressed T-type calcium channels(TTCCs)maintain calcium homeostasis in cancer cells,and calcium has a role in chemoresistance.Therefore,the aim of this study was to test the adjuvant role of TTA-A2,a TTCC blocker,in enhancing the anticancer effect of PTX on the A549 lung adenocarcinoma cell line.Methods:Morphology assay,calcium imaging assay,clonogenic assay,apoptosis assay,and real-time polymerase chain reaction(real-time PCR)were performed to find the adjuvant role of TTA-A2.Samples were treated with PTX at 10 nM concentration and TTA-A2 at 50 and 100 nM concentrations.PTX and TTA-A2 were used in the combination treatment at 10 and 100 nM concentrations,respectively.Results:Immunocytochemistry confirmed the expression of TTCC in A549 cells.Morphology assay showed altered morphology of A549 cells.The adjuvant role of TTA-A2 was observed in the calcium imaging assay in spheroids,in the clonogenic assay in monolayers,and in the apoptosis assay in both cultures.With real-time PCR,it was observed that,even though cells express the mRNA of Pgp,it is non-significant upon treatment with PTX and TTA-A2.Conclusion:TTA-A2 can be used as an adjuvant to reduce chemoresistance in cancer cells as well as to enhance the anticancer effect of the standard anticancer drug PTX.Being a potent TTCC inhibitor,TTA-A2 may also enhance the anticancer effects of other anticancer drugs.展开更多
Iron overload can lead to iron deposits in many tissues,particularly in the heart.It has also been shown to be associated with elevated oxidative stress in tissues.Elevated cardiac iron deposits can lead to iron overl...Iron overload can lead to iron deposits in many tissues,particularly in the heart.It has also been shown to be associated with elevated oxidative stress in tissues.Elevated cardiac iron deposits can lead to iron overload cardiomyopathy,a condition which provokes mortality due to heart failure in iron-overloaded patients.Currently,the mechanism of iron uptake into cardiomyocytes is still not clearly understood.Growing evidence suggests L-type Ca2+channels(LTCCs)as a possible pathway for ferrous iron(Fe2+)uptake into cardiomyocytes under iron overload conditions.Nevertheless,controversy still exists since some findings on pharmacological interventions and those using different cell types do not support LTCC’s role as a portal for iron uptake in cardiac cells.Recently,T-type Ca2+channels (TTCC)have been shown to play an important role in the diseased heart.Although TTCC and iron uptake in cardiomyocytes has not been investigated greatly,a recent finding indicated that TTCC could be an important portal in thalassemic hearts.In this review,comprehensive findings collected from previous studies as well as a discussion of the controversy regarding iron uptake mechanisms into cardiomyocytes via calcium channels are presented with the hope that understanding the cellular iron uptake mechanism in cardiomyocytes will lead to improved treatment and prevention strategies,particularly in iron-overloaded patients.展开更多
文摘Regulation of intracellular calcium is an important signaling mechanism for cell proliferation in both normal and cancerous cells. In normal epithelial cells, free calcium concentration is essential for cells to enter and accomplish the S phase and the M phase of the cell cycle. In contrast, cancerous cells can pass these phases of the cell cycle with much lower cytoplasmic free calcium concentrations, indicating an alternative mechanism has developed for fulfilling the intracellular calcium requirement for an increased rate of DNA synthesis and mitosis of fast replicating cancerous cells. The detailed mechanism underlying the altered calcium loading pathway remains unclear; however, there is a growing body of evidence that suggests the T-type Ca2+ channel is abnormally expressed in cancerous cells and that blockade of these channels may reduce cell proliferation in addition to inducing apoptosis. Recent studies also show that the expression of T-type Ca2+ channels in breast cancer cells is proliferation state dependent, i.e. the channels are expressed at higher levels during the fast-replication period, and once the cells are in a non-proliferation state, expression of this channel isminimal. Therefore, selectively blocking calcium entry into cancerous cells may be a valuable approach for preventing tumor growth. Since T-type Ca2+ channels are not expressed in epithelial cells, selective T-type Ca2+ channel blockers may be useful in the treatment of certain types of cancers.
基金the National Natural Science Foundation of China,No.81100831the Medical Science Foundation of Guangdong Health Department,No.B2011303
文摘Human neuroblastoma cells (SH-SY5Y) have similar structures and functions as neural cells and have been frequently used for cell culture studies of neural cell functions.Previous studies have revealed L-and N-type calcium channels in SH-SY5Y cells.However,the distribution of the low-voltage activated calcium channel (namely called T-type calcium channel,including Cav3.1,Cav3.2,and Cav3.3) in SH-SY5Y cells remains poorly understood.The present study detected mRNA and protein expres-sion of the T-type calcium channel (Cav3.1,Cav3.2,and Cav3.3) in cultured SH-SY5Y cells using real-time polymerase chain reaction (PCR) and western blot analysis.Results revealed mRNA and protein expression from all three T-type calcium channel subtypes in SH-SY5Y cells.Moreover,Cav3.1 was the predominant T-type calcium channel subtype in SH-SY5Y cells.
基金supported by the National Natural Science Foundation,Beijing,People’s Republic of China(81671058 and 81730031 to YW and 81401089 to MD)the National Research Foundation of Korea grants funded by the Republic of Korea(2019R1I1A1A01057744 to YK)the Foundation of Shanghai Municipal Science and Technology Commission(19ZR1407500 to FS)。
文摘In the current study,we sought to investigate whether T-type Ca^(2+)channels(TCCs)in the brain are involved in generating post-anesthetic hyperexcitatory behaviors(PAHBs).We found that younger rat pups(postnatal days 9-11)had a higher incidence of PAHBs and higher PAHB scores than older pups(postnatal days16-18)during emergence from sevoflurane anesthesia.The power spectrum of the theta oscillations(4 Hz-8 Hz)in the prefrontal cortex was significantly enhanced in younger pups when PAHBs occurred,while there were no significant changes in older pups.Both the power of theta oscillations and the level of PAHBs were significantly reduced by the administration of TCC inhibitors.Moreover,the sensitivity of TCCs in the medial dorsal thalamic nucleus to sevoflurane was found to increase with age by investigating the kinetic properties of TCCs in vitro.TCCs were activated by potentiated GABAergic depolarization with a sub-anesthetic dose of sevoflurane(1%).These data suggest that(1)TCCs in the brain contribute to the generation of PAHBs and the concomitant electroencephalographic changes;(2)the stronger inhibitory effect of sevoflurane contributes to the lack of PAHBs in older rats;and(3)the contribution of TCCs to PAHBs is not mediated by a direct effect of sevoflurane on TCCs.
基金This work was supported by Impacting Research Innovation and Technology(project code:5450)University Grant Commission fellowship(Ref.no.21/12/2014(ii)EU-V)。
文摘Aim:Chemoresistance is a prevalent issue in cancer treatment.Paclitaxel(PTX)is a microtubule-binding anticancer drug used in various cancer treatments.However,cancer cells often show chemoresistance against PTX with the help of P-glycoprotein(Pgp)-a drug efflux pump.It has also been observed that overexpressed T-type calcium channels(TTCCs)maintain calcium homeostasis in cancer cells,and calcium has a role in chemoresistance.Therefore,the aim of this study was to test the adjuvant role of TTA-A2,a TTCC blocker,in enhancing the anticancer effect of PTX on the A549 lung adenocarcinoma cell line.Methods:Morphology assay,calcium imaging assay,clonogenic assay,apoptosis assay,and real-time polymerase chain reaction(real-time PCR)were performed to find the adjuvant role of TTA-A2.Samples were treated with PTX at 10 nM concentration and TTA-A2 at 50 and 100 nM concentrations.PTX and TTA-A2 were used in the combination treatment at 10 and 100 nM concentrations,respectively.Results:Immunocytochemistry confirmed the expression of TTCC in A549 cells.Morphology assay showed altered morphology of A549 cells.The adjuvant role of TTA-A2 was observed in the calcium imaging assay in spheroids,in the clonogenic assay in monolayers,and in the apoptosis assay in both cultures.With real-time PCR,it was observed that,even though cells express the mRNA of Pgp,it is non-significant upon treatment with PTX and TTA-A2.Conclusion:TTA-A2 can be used as an adjuvant to reduce chemoresistance in cancer cells as well as to enhance the anticancer effect of the standard anticancer drug PTX.Being a potent TTCC inhibitor,TTA-A2 may also enhance the anticancer effects of other anticancer drugs.
基金supported by grants from the National Natural Science Foundation of China (81171042,81070893 and 81221002)the Beijing Outstanding Ph.D.Program Mentor Grantthe Specialized Research Fund for Doctoral Programs of Higher Education, China(20110001110058)
基金Supported by Thailand Research Fund grants RTA5280006 (Chattipakorn N)BRG5480003(Chattipakorn S)+1 种基金the National Research Council of Thailand(Chattipakorn N)the Thai-land Research Fund Royal Golden Jubilee project(Kumfu S and Chattipakorn N)
文摘Iron overload can lead to iron deposits in many tissues,particularly in the heart.It has also been shown to be associated with elevated oxidative stress in tissues.Elevated cardiac iron deposits can lead to iron overload cardiomyopathy,a condition which provokes mortality due to heart failure in iron-overloaded patients.Currently,the mechanism of iron uptake into cardiomyocytes is still not clearly understood.Growing evidence suggests L-type Ca2+channels(LTCCs)as a possible pathway for ferrous iron(Fe2+)uptake into cardiomyocytes under iron overload conditions.Nevertheless,controversy still exists since some findings on pharmacological interventions and those using different cell types do not support LTCC’s role as a portal for iron uptake in cardiac cells.Recently,T-type Ca2+channels (TTCC)have been shown to play an important role in the diseased heart.Although TTCC and iron uptake in cardiomyocytes has not been investigated greatly,a recent finding indicated that TTCC could be an important portal in thalassemic hearts.In this review,comprehensive findings collected from previous studies as well as a discussion of the controversy regarding iron uptake mechanisms into cardiomyocytes via calcium channels are presented with the hope that understanding the cellular iron uptake mechanism in cardiomyocytes will lead to improved treatment and prevention strategies,particularly in iron-overloaded patients.
