Objectives:Mitochondrial Ca^(2+)uniporter(MCU)provides a Ca^(2+)influx pathway from the cytosol into the mitochondrial matrix and a moderate mitochondrial Ca^(2+)rise stimulates ATP production and cell growth.MCU is h...Objectives:Mitochondrial Ca^(2+)uniporter(MCU)provides a Ca^(2+)influx pathway from the cytosol into the mitochondrial matrix and a moderate mitochondrial Ca^(2+)rise stimulates ATP production and cell growth.MCU is highly expressed in various cancer cells including breast cancer cells,thereby increasing the capacity of mitochondrial Ca^(2+)uptake,ATP production,and cancer cell proliferation.The objective of this study was to examine MCU inhibition as an anti-cancer mechanism.Methods:The effects of MCU-i4,a newly developed MCU inhibitor,on cell viability,apoptosis,cytosolic Ca^(2+),mitochondrial Ca^(2+)and potential,glycolytic rate,generation of ATP,and reactive oxygen species,were examined in breast cancer BT474 cells.Results:MCU-i4 caused apoptotic cell death,and it decreased and increased,respectively,mitochondrial and cytosolic Ca^(2+)concentration.Inhibition of MCU by MCU-i4 revealed that cytosolic Ca^(2+)elevation resulted from endoplasmic reticulum(ER)Ca^(2+)release via inositol 1,4,5-trisphosphate receptors(IP3R)and ryanodine receptors(RYR).Unexpectedly,MCU-i4 enhanced glycolysis and ATP production;it also triggered a large production of reactive oxygen species(ROS)and mitochondrial membrane potential collapse.Conclusion:Cytotoxic mechanisms of MCU-i4 in cancer cells involved enhanced glycolysis and heightened formation of ATP and ROS.It is conventionally believed that cancer cell death could be caused by inhibition of glycolysis.Our observations suggest cancer cell death could also be induced by increased glycolytic metabolism.展开更多
Aim Chronic myelogenous leukemia （CML） is a hematopoietic stem cell cancer caused by the Bcr-Abl tyrosine kinase which arises from Philadelphia chromosome （Ph） translocation. Imatinib showed potent antitumor effic...Aim Chronic myelogenous leukemia （CML） is a hematopoietic stem cell cancer caused by the Bcr-Abl tyrosine kinase which arises from Philadelphia chromosome （Ph） translocation. Imatinib showed potent antitumor efficacy on CML but caused resistance, therefore, other chemotherapeutic drugs for CML are expected. Phosphati-dylinositol 3-kinases （PI3Ks） are lipid kinases that preferentially phosphorylate phosphatidylinositol 4,5-bisphos- phate （PIP2） to generate phosphatidylinositol 3,4,5-trisphosphate （PIP3） which activates the downstream Akt and mammalian target of rapamycin （mTOR） , and therefore play important roles in controlling signal pathways involved in cell proliferation, etc. ZSTK474, a specific PI3K inhibitor, was reported to show potent antitumor efficacy on various solid tumors, while the anti｜eukemia effect was not yet reported. Herein, the effects of ZSTK474 on K562 CML cells as well as the adriamycin-resistant human leukemia cells （K562/ADR） are reported. Methods Cell proliferation inhibition was detected by MTT assay. Cell cycle was analyzed by FACS. The expression of cell cycle related molecules like p27 and p21 was detected by western blot and qRT-PCR. Synergistic effect of ZSTK474 and Imatinib was evaluated by MTT assay and analyzed using Calcusyn. Results MTT assay showed that ZSTK474 could inhibit the proliferation of K562 and K562/ADR cells with ICs0 as 4 69 μmol · L^-1 and 7 57 μmol·L^-1 re- spectively. ZSTK474 induced cell cycle G1 arrest in the above two cell lines dose-dependently after 48 h treatment. Western blot analysis demonstrated ZSTK474 treatment decreased the level of cyclin D1 and increased the expres- sion of p27 and p21. Similar results in mRNA level were obtained by qRT-PCR assay. Combination of ZSTK474 and Imatinib indicated synergistic effect in both cell lines. Conclusion ZSTK474 exhibited anti-leukemia activity alone, and showed synergistic effect when combined with Imatinib, on CML K562 cells. These findings suggest possible application of ZSTK474 in CML treatment.展开更多
基金China Medical University and China Medical University Hospital,Taiwan for providing fundings(CMU111-S-20,CMU112-S-59,DMR-112-067)ECS thanks An Nan Hospital for support(ANHRF112-04).
文摘Objectives:Mitochondrial Ca^(2+)uniporter(MCU)provides a Ca^(2+)influx pathway from the cytosol into the mitochondrial matrix and a moderate mitochondrial Ca^(2+)rise stimulates ATP production and cell growth.MCU is highly expressed in various cancer cells including breast cancer cells,thereby increasing the capacity of mitochondrial Ca^(2+)uptake,ATP production,and cancer cell proliferation.The objective of this study was to examine MCU inhibition as an anti-cancer mechanism.Methods:The effects of MCU-i4,a newly developed MCU inhibitor,on cell viability,apoptosis,cytosolic Ca^(2+),mitochondrial Ca^(2+)and potential,glycolytic rate,generation of ATP,and reactive oxygen species,were examined in breast cancer BT474 cells.Results:MCU-i4 caused apoptotic cell death,and it decreased and increased,respectively,mitochondrial and cytosolic Ca^(2+)concentration.Inhibition of MCU by MCU-i4 revealed that cytosolic Ca^(2+)elevation resulted from endoplasmic reticulum(ER)Ca^(2+)release via inositol 1,4,5-trisphosphate receptors(IP3R)and ryanodine receptors(RYR).Unexpectedly,MCU-i4 enhanced glycolysis and ATP production;it also triggered a large production of reactive oxygen species(ROS)and mitochondrial membrane potential collapse.Conclusion:Cytotoxic mechanisms of MCU-i4 in cancer cells involved enhanced glycolysis and heightened formation of ATP and ROS.It is conventionally believed that cancer cell death could be caused by inhibition of glycolysis.Our observations suggest cancer cell death could also be induced by increased glycolytic metabolism.
文摘Aim Chronic myelogenous leukemia （CML） is a hematopoietic stem cell cancer caused by the Bcr-Abl tyrosine kinase which arises from Philadelphia chromosome （Ph） translocation. Imatinib showed potent antitumor efficacy on CML but caused resistance, therefore, other chemotherapeutic drugs for CML are expected. Phosphati-dylinositol 3-kinases （PI3Ks） are lipid kinases that preferentially phosphorylate phosphatidylinositol 4,5-bisphos- phate （PIP2） to generate phosphatidylinositol 3,4,5-trisphosphate （PIP3） which activates the downstream Akt and mammalian target of rapamycin （mTOR） , and therefore play important roles in controlling signal pathways involved in cell proliferation, etc. ZSTK474, a specific PI3K inhibitor, was reported to show potent antitumor efficacy on various solid tumors, while the anti｜eukemia effect was not yet reported. Herein, the effects of ZSTK474 on K562 CML cells as well as the adriamycin-resistant human leukemia cells （K562/ADR） are reported. Methods Cell proliferation inhibition was detected by MTT assay. Cell cycle was analyzed by FACS. The expression of cell cycle related molecules like p27 and p21 was detected by western blot and qRT-PCR. Synergistic effect of ZSTK474 and Imatinib was evaluated by MTT assay and analyzed using Calcusyn. Results MTT assay showed that ZSTK474 could inhibit the proliferation of K562 and K562/ADR cells with ICs0 as 4 69 μmol · L^-1 and 7 57 μmol·L^-1 re- spectively. ZSTK474 induced cell cycle G1 arrest in the above two cell lines dose-dependently after 48 h treatment. Western blot analysis demonstrated ZSTK474 treatment decreased the level of cyclin D1 and increased the expres- sion of p27 and p21. Similar results in mRNA level were obtained by qRT-PCR assay. Combination of ZSTK474 and Imatinib indicated synergistic effect in both cell lines. Conclusion ZSTK474 exhibited anti-leukemia activity alone, and showed synergistic effect when combined with Imatinib, on CML K562 cells. These findings suggest possible application of ZSTK474 in CML treatment.
