The Regulation Mechanism Of CD147 On Oxidative Phosphorylation In Pancreatic Cancer Stem Cells

Pancreatic cancer is a highly malignant cancer with strong resistance to chemotheraptic drugs,prone to recurrence and metastasis,and poor prognosis.At present,effective pancreatic cancer treatment is one of the difficulties in medical research.According to the cancer stem cell theory,a minority of cells in the tumor tissue,that is,cancer stem cells,have the ability to generate the heterogeneous cancer cells,and possess the potentials of self-renewal,high tumorigenicity and active differentiation.A large number of studies have shown that cancer stem cells are involved in the process of tumor invasion,metastasis,and drug resistance and so on.And,cancer stem cells are the culprit for the incurable tumor.Notably,the metabolic pattern of cancer stem cells is different from that of non-cancer stem cells.Thus,determining the role of cancer stem cell metabolism in tumorigenesis and development has become a new focus in the field of cancer research.Our previous studies have shown that CD147 is highly expressed in pancreatic cancer stem cells and that the expression of CD147 is related to the pancreatic cancer stem cells potentials,such as epithelial-mesenchymal transition,chemo/radio-resistance,anoikis resistance,metastasis and recurrence.Therefore,the purpose of this study is to investigate the influence of CD147 on the metabolism of pancreatic cancer stem cells and the corresponding regulatory mechanism.This study included three parts.In the first part,we analyzed the influence of CD147on the potentials of pancreatic cancer stem cells.We found that the knock-down or knock-in CD147 expression altered the formation of tumorsphere and the expression of stemneess gene in pancreatic cancer cells.HAb18,the CD147 antibody,blocked the CD147 signaling,significantly inhibited the expression of the stemness gene and stem cell transcription factor,and reduced the ratio of the cancer stem cells subpopulation.These results suggested that CD147 has a significant regulatory effect on the potential of pancreatic cancer stem cells.Blocking the CD147 signal by antibody interfered with the potential of pancreatic cancer stem cells.In the second part,we mainly examined the metabolic characteristics of pancreatic cancer stem cells.Using flow cytometry or tumorsphere culture,we isolated and enriched pancreatic cancer stem cells from pancreatic cancer cell lines or pancreatic cancer PDX tissues,and analyzed their metabolic characteristics.Compared with pancreatic cancer cells,the ATP production,the mitochondrial complex I activity in pancreatic cancer stem cells was significantly enhanced,and the expression of mitochondrial complex I core subunit NDUFS1 and NDUFS8 was significantly increased.Knock-down the expression of NDUFS1/S8 by siRNA interference,the ATP production and the ratio of ALDH⁺or CD133⁺CD44⁺caner stem cell subpopulations were significantly decreased,while stable interference NDUFS1/S8 expression significantly reduced the ability of tumorsphere formation.In addition,NDUFS1/S8 knock-down also reduced the expression of histone deacetylase SIRT1 and its downstream stem gene KLF4.These results suggest that pancreatic cancer stem cells gain energy for survival by way of mitochondrial oxidative phosphorylation.Mechanismly,pancreatic cancer stem cells highly expressed mitochondrial complex I core subunit NDUFS1/S8,which promoted mitochondrial oxidative phosphorylation and provided energy to pancreatic cancer stem cells.Meanwhile,NDUFS1/S8 promoted pancreatic cancer stem cells potentials by up-regulating the SIRT1/KLF4 signaling pathway.In the third part,we explored whether CD147 affected the pancreatic cancer stem cells by regulating mitochondrial oxidative phosphorylation.We detected the metabolic characteristics and the expression of NDUFS1/NDUFS8/SIRT1/KLF4 in CD147knock-down or knock-in pancreatic cancer cells.We found that the expression of CD147enhanced oxygen consumption,ATP production and mitochondrial complex I and II activity,suggesting that CD147 promotes oxidative phosphorylation in pancreatic cancer cells.In molecular level,CD147 promoted the expression of NDUFS1/S8 as well as its downstream SIRT1,KLF4 and mitochondrial ^ser727pSTAT3.These results suggest that the high expression of CD147 in pancreatic cancer cells promoted the oxidative phosphorylation of pancreatic cancer stem cells by up-regulating NDUFS1/S8 expression,and then CD147 increased the potentials of pancreatic cancer stem cells by enhancing the SIRT1/KLF4 signal or/and mitochondrial ^ser727pSTAT3 activation.In conclusion,the results of this study showed that the high expression of CD147 in pancreatic cancer stem cells increased the mitochondrial complex I activity by up-regulating NDUFS1/S8 expression,and then promoted the oxidative phosphorylation of pancreatic cancer stem cells.Furthermore,CD147 enhanced the potentials of pancreatic cancer stem cells by up-regulating the NDUFS1/S8 downstream SIRT1/KLF4 signal.