BACKGROUND Pancreatic cancer is a leading cause of cancer-related deaths.Increased activity of the epidermal growth factor receptor(EGFR)is often observed in pancreatic cancer,and the small molecule EGFR inhibitor erl...BACKGROUND Pancreatic cancer is a leading cause of cancer-related deaths.Increased activity of the epidermal growth factor receptor(EGFR)is often observed in pancreatic cancer,and the small molecule EGFR inhibitor erlotinib has been approved for pancreatic cancer therapy by the food and drug administration.Nevertheless,erlotinib alone is ineffective and should be combined with other drugs to improve therapeutic outcomes.We previously showed that certain receptor tyrosine kinase inhibitors can increase mitochondrial membrane potential(Δψm),facilitate tumor cell uptake ofΔψm-sensitive agents,disrupt mitochondrial homeostasis,and subsequently trigger tumor cell death.Erlotinib has not been tested for this effect.AIM To determine whether erlotinib can elevateΔψm and increase tumor cell uptake ofΔψm-sensitive agents,subsequently triggering tumor cell death.METHODSΔψm-sensitive fluorescent dye was used to determine how erlotinib affectsΔψm in pancreatic adenocarcinoma(PDAC)cell lines.The viability of conventional and patient-derived primary PDAC cell lines in 2D-and 3D cultures was measured after treating cells sequentially with erlotinib and mitochondria-targeted ubiquinone(MitoQ),aΔψm-sensitive MitoQ.The synergy between erlotinib and MitoQ was then analyzed using SynergyFinder 2.0.The preclinical efficacy of the twodrug combination was determined using immune-compromised nude mice bearing PDAC cell line xenografts.RESULTS Erlotinib elevatedΔψm in PDAC cells,facilitating tumor cell uptake and mitochondrial enrichment ofΔψm-sensitive agents.MitoQ triggered caspase-dependent apoptosis in PDAC cells in culture if used at high doses,while erlotinib pretreatment potentiated low doses of MitoQ.SynergyFinder suggested that these drugs synergistically induced tumor cell lethality.Consistent with in vitro data,erlotinib and MitoQ combination suppressed human PDAC cell line xenografts in mice more effectively than single treatments of each agent.CONCLUSION Our findings suggest that a combination of erlotinib and MitoQ has the potential to suppress pancreatic tumor cell viability effectively.展开更多
Mitochondrial dysfunction, oxidative stress, and their regulation are important fields of study in modem clinical research.Exogenous CoQ is an efficient therapeutic agent, yet its application has leads to continued su...Mitochondrial dysfunction, oxidative stress, and their regulation are important fields of study in modem clinical research.Exogenous CoQ is an efficient therapeutic agent, yet its application has leads to continued suppression of endogenous CoQ synthesis,which limits CoQ applicability. Our aim was to study the state of mitochondrial electron transport chain components, CoQ contentand redox state, superoxide anion radicals and NO production rates, and active MMP-2 and MMP-9 content in rat liver and heartunder treatment with Doxorubicin, CoQ10, and complex preparation of modulators and precursors of CoQ biosynthesis （EPMcomplex）. The results demonstrate that treatment with EPM complex and CoQ10 in addition to Doxorubicin administration exertsprotective effect on liver and heart mitochondria, evidenced by restoration of electron transport in respiratory chain, which isexpressed as decreased nitrile complexes formation with Fe-S-proteins and increased ubisemiquinone content. The protective effectsof EPM complex on mitochondrial electron transport chain under Doxorubicin administration is on par with those of CoQ10, anddecreased MMP2 and MMP9 activities signify lessened extracellular matrix destruction. These results demonstrate the viability ofapproaches to correct adverse effects of Doxorubicin by treatment with CoQ10 and e complex of precursors and modulators of itsbiosynthesis.展开更多
A membrane-bound protein was purified from rat liver mitochondria. After being di-gested with V8 protease, two peptides containing identical 14 amino acid residue sequences were obtained. Using the 14 amino acid pepti...A membrane-bound protein was purified from rat liver mitochondria. After being di-gested with V8 protease, two peptides containing identical 14 amino acid residue sequences were obtained. Using the 14 amino acid peptide derived DNA sequence as gene specific primer, the cDNA of correspondent gene 5′-terminal and 3′-terminal were obtained by RACE technique. The full-length cDNA that encoded a protein of 616 amino acids was thus cloned, which included the above mentioned peptide sequence. The full length cDNA was highly homologous to that of human ETF-QO, indicating that it may be the cDNA of rat ETF-QO. ETF-QO is an iron sulfur protein located in mitochondria inner membrane containing two kinds of redox center: FAD and [4Fe-4S] center. After comparing the sequence from the cDNA of the 616 amino acids protein with that of the mature protein of rat liver mitochondria, it was found that the N terminal 32 amino acid residues did not exist in the mature protein, indicating that the cDNA was that of ETF-QOp. When the cDNA was expressed in Saccharomyces cerevisiae with inducible vectors, the protein product was enriched in mitochondrial fraction and exhibited electron transfer activity (NBT re-ductase activity) of ETF-QO. Results demonstrated that the 32 amino acid peptide was a mito-chondrial targeting peptide, and both FAD and iron-sulfur cluster were inserted properly into the expressed ETF-QO. ETF-QO had a high level expression in rat heart, liver and kidney. The fu-sion protein of GFP-ETF-QO co-localized with mitochondria in COS-7 cells.展开更多
It is proved by using the Dixon plot and the Lineweaver-Burk plot that thenoyltrifluoroacetone （TTFA） has two inhibitive sites affecting the reduction of ubiquinone catalyzed by succinate-ubiquinone reductase. The h...It is proved by using the Dixon plot and the Lineweaver-Burk plot that thenoyltrifluoroacetone （TTFA） has two inhibitive sites affecting the reduction of ubiquinone catalyzed by succinate-ubiquinone reductase. The high affinity site （inhibited at the concentration of thenoyltrifluoroacetone less than 20 μmol/L） shows noncompetitive with substrate Q<sub>2</sub>, while the low affinity site （inhibited at the concentration of TTFA over 20 μmol/L） shows competitive. It is suggested that both the reducing steps of Q→QH and QH→QH<sub>2</sub> are inhibited by thenoyltrifluoroacetone.展开更多
The energy shift toward glycolysis is one of the hallmarks of cancer.Complex I is a vital enzyme complex necessary for oxidative phosphorylation.The mitochondrially encoded NADH:ubiquinone oxidoreductase core subunit ...The energy shift toward glycolysis is one of the hallmarks of cancer.Complex I is a vital enzyme complex necessary for oxidative phosphorylation.The mitochondrially encoded NADH:ubiquinone oxidoreductase core subunit 1(MT-ND1)is the largest subunit coded by mitochondria of complex I.The present study summarizes the structure and biological function of MT-ND1.From databases and literature,the expressions and mutations of MT-ND1 in a variety of cancers have been reviewed.MT-ND1 may be a biomarker for cancer diagnosis and prognosis.It is also a potential target for cancer therapy.展开更多
Upon infection into human red cell,Plasmodium falciparum differentiates into asexual and sexual(gametocyte) stages.The mitochondrion is a tubular-cristate organelle,functionally and structurally different between the ...Upon infection into human red cell,Plasmodium falciparum differentiates into asexual and sexual(gametocyte) stages.The mitochondrion is a tubular-cristate organelle,functionally and structurally different between the two stages.Genes and proteins involving metabolic and functional roles,protein targeting and import to this organelle, are comprehensively reviewed.The genes and proteins of the electron transport system are identified, partially characterized in human and rodent malaria parasites consisting of a single subunit of NADH dehydrogenase, two subunits of succinate dehydrogenase,cytochrome C reductase and cytochrome Coxidase.One of the primary functional roles of the mitochondrion in the parasite is the coordination of pyrimidine biosynthesis, the electron transport system and oxygen utilization through dihydroorotate dehydrogenase.All enzymes of tricarboxylic acid cycle,pyruvate dehydrogenase complex and some enzymes of ATP synthase,are identified and partially characterized using the completed P.falciparum genome.Some metabolic and functional roles of the organelle include oxidative phosphorylation,ubiquinone and heme biosynthesis,antioxidant defense and redox balance.Recent physiological studies involve membrane potential maintenance,cellular signaling and cation homeostasis.The organelle is a target for antimalarial drug,i.e.atovaquone.Based on the lines of evidence, we hypothesize that the parasite exhibits metabolic adaptation of the underdeveloped mitochondrial organelle to life in the mosquito vector and the human host.展开更多
为调查大肠杆菌高产辅酶Q(CoQ)的可能性,首先研究大肠杆菌生物合成关键基因ubiCA强化表达对大肠杆菌CoQ产量的影响。本文构建了含有ubiCA基因的5个表达质粒,将其分别转入E.coli JM 83或BL 21(DE 3)菌株中,定量分析这些转化子的辅酶Q产...为调查大肠杆菌高产辅酶Q(CoQ)的可能性,首先研究大肠杆菌生物合成关键基因ubiCA强化表达对大肠杆菌CoQ产量的影响。本文构建了含有ubiCA基因的5个表达质粒,将其分别转入E.coli JM 83或BL 21(DE 3)菌株中,定量分析这些转化子的辅酶Q产量。结果表明ubiCA基因在ubiC自身启动子(pub iCA-lacZF)介导下的表达最有效,重组菌CoQ产量达到对照的3.5倍,由此推测ubiCA基因的表达可能与其启动子序列有关。展开更多
In order to provide scientific material for promulgating the giant panda(Ailuropoda melanoleuca)nucleus gene inheritance characteristic,for the formulation gene protection countermeasure and to put resources to ration...In order to provide scientific material for promulgating the giant panda(Ailuropoda melanoleuca)nucleus gene inheritance characteristic,for the formulation gene protection countermeasure and to put resources to rational use,the expression sequence of ubiquinol-cytochrome c reductase complex ubiquinone-binding protein(QP-C)gene from the giant panda was analyzed.The result indicates that the cDNA sequence length is 335 bp and contains a 246-nucleotide open reading frame encoding 81 amino acid residues.The pI of the protein is 10.50 and its mole cular weight is 9.60×103 Da.Topology prediction shows these QP-C proteins contain a N-glycosylation site,a potential protein kinase C phosphorylation site and a Casein kinase II phosphorylation site.Comparing the cDNA sequence with amino acid sequence of giant panda’s QP-C gene and cDNA sequence with the amino acid sequence of other species’ QP-C gene shows high similarity.The similarity is 82.3% to 95.2% and 81.5% to 95.1%.展开更多
基金Supported by NIH/National Cancer Institute Grant,No.R01CA138441 and No.R01CA269452UW Madison Centene Pancreas Cancer Collaborative Award,No.21-8568.
文摘BACKGROUND Pancreatic cancer is a leading cause of cancer-related deaths.Increased activity of the epidermal growth factor receptor(EGFR)is often observed in pancreatic cancer,and the small molecule EGFR inhibitor erlotinib has been approved for pancreatic cancer therapy by the food and drug administration.Nevertheless,erlotinib alone is ineffective and should be combined with other drugs to improve therapeutic outcomes.We previously showed that certain receptor tyrosine kinase inhibitors can increase mitochondrial membrane potential(Δψm),facilitate tumor cell uptake ofΔψm-sensitive agents,disrupt mitochondrial homeostasis,and subsequently trigger tumor cell death.Erlotinib has not been tested for this effect.AIM To determine whether erlotinib can elevateΔψm and increase tumor cell uptake ofΔψm-sensitive agents,subsequently triggering tumor cell death.METHODSΔψm-sensitive fluorescent dye was used to determine how erlotinib affectsΔψm in pancreatic adenocarcinoma(PDAC)cell lines.The viability of conventional and patient-derived primary PDAC cell lines in 2D-and 3D cultures was measured after treating cells sequentially with erlotinib and mitochondria-targeted ubiquinone(MitoQ),aΔψm-sensitive MitoQ.The synergy between erlotinib and MitoQ was then analyzed using SynergyFinder 2.0.The preclinical efficacy of the twodrug combination was determined using immune-compromised nude mice bearing PDAC cell line xenografts.RESULTS Erlotinib elevatedΔψm in PDAC cells,facilitating tumor cell uptake and mitochondrial enrichment ofΔψm-sensitive agents.MitoQ triggered caspase-dependent apoptosis in PDAC cells in culture if used at high doses,while erlotinib pretreatment potentiated low doses of MitoQ.SynergyFinder suggested that these drugs synergistically induced tumor cell lethality.Consistent with in vitro data,erlotinib and MitoQ combination suppressed human PDAC cell line xenografts in mice more effectively than single treatments of each agent.CONCLUSION Our findings suggest that a combination of erlotinib and MitoQ has the potential to suppress pancreatic tumor cell viability effectively.
文摘Mitochondrial dysfunction, oxidative stress, and their regulation are important fields of study in modem clinical research.Exogenous CoQ is an efficient therapeutic agent, yet its application has leads to continued suppression of endogenous CoQ synthesis,which limits CoQ applicability. Our aim was to study the state of mitochondrial electron transport chain components, CoQ contentand redox state, superoxide anion radicals and NO production rates, and active MMP-2 and MMP-9 content in rat liver and heartunder treatment with Doxorubicin, CoQ10, and complex preparation of modulators and precursors of CoQ biosynthesis （EPMcomplex）. The results demonstrate that treatment with EPM complex and CoQ10 in addition to Doxorubicin administration exertsprotective effect on liver and heart mitochondria, evidenced by restoration of electron transport in respiratory chain, which isexpressed as decreased nitrile complexes formation with Fe-S-proteins and increased ubisemiquinone content. The protective effectsof EPM complex on mitochondrial electron transport chain under Doxorubicin administration is on par with those of CoQ10, anddecreased MMP2 and MMP9 activities signify lessened extracellular matrix destruction. These results demonstrate the viability ofapproaches to correct adverse effects of Doxorubicin by treatment with CoQ10 and e complex of precursors and modulators of itsbiosynthesis.
基金This project was supported by the Knowledge Innovation Program of the Chinese Academy of Sciences.
文摘A membrane-bound protein was purified from rat liver mitochondria. After being di-gested with V8 protease, two peptides containing identical 14 amino acid residue sequences were obtained. Using the 14 amino acid peptide derived DNA sequence as gene specific primer, the cDNA of correspondent gene 5′-terminal and 3′-terminal were obtained by RACE technique. The full-length cDNA that encoded a protein of 616 amino acids was thus cloned, which included the above mentioned peptide sequence. The full length cDNA was highly homologous to that of human ETF-QO, indicating that it may be the cDNA of rat ETF-QO. ETF-QO is an iron sulfur protein located in mitochondria inner membrane containing two kinds of redox center: FAD and [4Fe-4S] center. After comparing the sequence from the cDNA of the 616 amino acids protein with that of the mature protein of rat liver mitochondria, it was found that the N terminal 32 amino acid residues did not exist in the mature protein, indicating that the cDNA was that of ETF-QOp. When the cDNA was expressed in Saccharomyces cerevisiae with inducible vectors, the protein product was enriched in mitochondrial fraction and exhibited electron transfer activity (NBT re-ductase activity) of ETF-QO. Results demonstrated that the 32 amino acid peptide was a mito-chondrial targeting peptide, and both FAD and iron-sulfur cluster were inserted properly into the expressed ETF-QO. ETF-QO had a high level expression in rat heart, liver and kidney. The fu-sion protein of GFP-ETF-QO co-localized with mitochondria in COS-7 cells.
基金This work was co-supported by Grants NIH GM-16767 of USA and the National Natural Science Foundation of China
文摘It is proved by using the Dixon plot and the Lineweaver-Burk plot that thenoyltrifluoroacetone （TTFA） has two inhibitive sites affecting the reduction of ubiquinone catalyzed by succinate-ubiquinone reductase. The high affinity site （inhibited at the concentration of thenoyltrifluoroacetone less than 20 μmol/L） shows noncompetitive with substrate Q<sub>2</sub>, while the low affinity site （inhibited at the concentration of TTFA over 20 μmol/L） shows competitive. It is suggested that both the reducing steps of Q→QH and QH→QH<sub>2</sub> are inhibited by thenoyltrifluoroacetone.
基金supported by National Natural Science Foundation of China(No.82203232)Scientific Instrument Field Project of Shanghai Science and Technology Commission(No.22142202700)Shanghai Rising-Star Program(No.19QB1404700).
文摘The energy shift toward glycolysis is one of the hallmarks of cancer.Complex I is a vital enzyme complex necessary for oxidative phosphorylation.The mitochondrially encoded NADH:ubiquinone oxidoreductase core subunit 1(MT-ND1)is the largest subunit coded by mitochondria of complex I.The present study summarizes the structure and biological function of MT-ND1.From databases and literature,the expressions and mutations of MT-ND1 in a variety of cancers have been reviewed.MT-ND1 may be a biomarker for cancer diagnosis and prognosis.It is also a potential target for cancer therapy.
基金the UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases(CHEMAL)the National Science and Technology Development Agency of Thailand (Career Development Award)the Thailand Research Fund(Basic Research)
文摘Upon infection into human red cell,Plasmodium falciparum differentiates into asexual and sexual(gametocyte) stages.The mitochondrion is a tubular-cristate organelle,functionally and structurally different between the two stages.Genes and proteins involving metabolic and functional roles,protein targeting and import to this organelle, are comprehensively reviewed.The genes and proteins of the electron transport system are identified, partially characterized in human and rodent malaria parasites consisting of a single subunit of NADH dehydrogenase, two subunits of succinate dehydrogenase,cytochrome C reductase and cytochrome Coxidase.One of the primary functional roles of the mitochondrion in the parasite is the coordination of pyrimidine biosynthesis, the electron transport system and oxygen utilization through dihydroorotate dehydrogenase.All enzymes of tricarboxylic acid cycle,pyruvate dehydrogenase complex and some enzymes of ATP synthase,are identified and partially characterized using the completed P.falciparum genome.Some metabolic and functional roles of the organelle include oxidative phosphorylation,ubiquinone and heme biosynthesis,antioxidant defense and redox balance.Recent physiological studies involve membrane potential maintenance,cellular signaling and cation homeostasis.The organelle is a target for antimalarial drug,i.e.atovaquone.Based on the lines of evidence, we hypothesize that the parasite exhibits metabolic adaptation of the underdeveloped mitochondrial organelle to life in the mosquito vector and the human host.
文摘In order to provide scientific material for promulgating the giant panda(Ailuropoda melanoleuca)nucleus gene inheritance characteristic,for the formulation gene protection countermeasure and to put resources to rational use,the expression sequence of ubiquinol-cytochrome c reductase complex ubiquinone-binding protein(QP-C)gene from the giant panda was analyzed.The result indicates that the cDNA sequence length is 335 bp and contains a 246-nucleotide open reading frame encoding 81 amino acid residues.The pI of the protein is 10.50 and its mole cular weight is 9.60×103 Da.Topology prediction shows these QP-C proteins contain a N-glycosylation site,a potential protein kinase C phosphorylation site and a Casein kinase II phosphorylation site.Comparing the cDNA sequence with amino acid sequence of giant panda’s QP-C gene and cDNA sequence with the amino acid sequence of other species’ QP-C gene shows high similarity.The similarity is 82.3% to 95.2% and 81.5% to 95.1%.
