The Effect Of Lipid Metabolism Reprogramming On Radiotherapy Resistance Of Cervical Cancer And The Potential Molecular Mechanisms

BackgroundCervical cancer is the most common women malignancy and remains one of the leading causes of cancer-related deaths due to therapy resistance.Nearly around 460,000 new cases were diagnosied each year and about 274,000 patients died.Radiotherapy plays a significant role in the treatment of cervical cancer,especially,for wowen with locally advanced and recurent cancer.Despite continuous improvements in radiation technology,radioresistance is a bottleneck of treatment.Therefore,investigation of specific components and signaling pathways contributing to radioresistance,which are highly efficient and selective,may lead to advances in the radiotherapy of recurrent cervical.Metabolic reprogramming is a hallmark of malignant tumors.Previous studies have reported that they can induce tumor cells to tolerate apoptosis,promote tumor invasion and metastasis,and mediate chemotherapy resistance.But whether the metabolic reprogramming was involved in cervical cancer radioresistance remains elusive.Mitochondria are the main sites for the energy supply of cells.It is of great significance to maintain the normal function of the mitochondria to ensure the adequate energy supply in the stress state,which against apoptosis.Damaged mitochondria induced by reactive oxygen species(ROS),which produced during oxidative phosphorylation of mitochondria,can induce apoptosis through releasing Cytochrome C and Caspase species.So,removing the damaged mitochondria is imperative to maintain its normal function.Studies have found that radiotherapy can induce autophagy in glioma cells,and autophagy inhibitor(3-MA)can significantly enhance the radiation sensitivity of breast cancer MCF-7 cells,suggesting that autophagy could protect cell damage from radiation.Moreover,ATM promoted IR-induced autophagy via MAPK14 pathway,which contributed to radiosensitization of H1299 cells.But the effect of mitophagy on radiotherapy resistance of cervical cancer and the potential mechanism is still unclear.Therefore,this study intends to discuss the metabolic shift of cervical cancer cell under the cirumstance of radioresistance and the critical role of mitophagy in the radioresistance of cervical cancer cell.Objective1.To clarify the metabolic shift of cervical cancer cell under the cirumstance of radioresistance.2.To demonstrate the critical role of mitophagy in the radioresistance of cervical cancer cell.3.To explore the molecular mechanism by which the metabolic reprogamming induces mitophagy to induce radioresistance of cervical cancer cell.Materials and Methods1.The gene expression profile discrepancy between Hela and Hela-R cells was analyzed using gene chip.The expression characteristics of metabolic enzymes and their correlation were detected using Western-blot assays between Hela and Hela-R cells.2.The metabolic features of Hela and Hela-R cells were identified by metabolomics.The mitochondrial respiratory function was determined by Oxygen Comsumption Rate(OCAR)assay.The mitophagic flux was measured by electron microscope and two-photon laser scanning fluorescence microscopy(TPM).The mitochondrial biogenesis and mitochondrial capacity were determined by QPCR.The mitochondrial membrane potential(??)was measured by mitochondrial membrane potential assay kit with JC-1,and the mitochondrial damage was determined by a colorimetric quantitative detection kit for 8-hydroxydeoxyguanosine.3.The molecular mechanism by which the lipid metabolic reprogramming induces mitophagy to mediate radioresistance in cervical cancer was investigated by using cardiolipin synthetase 1(CRLS1)knockdown and overexpression cell models.Results1.Gene chips,Western-blot and metabolomics results showed that there was no significant difference in glycolysis in Hela-R cells,whereas the mitochondrial lipid oxidation was significantly increased in Hela-R cells compared with the parental Hela cells.2.Mitotracker and seahorse assays showed that mitochondrial function was significantly enhanced in Hela-R cells relative to the parental Hela ones.3.The electron microscopy and confocal results showed that the mitophagic flux in the Hela-R cells was significantly higher than the parental Hela ones under irradiation challenge.4.The increased mitophagy in Hela-R cells was induced by CRLS1-mediated synthesis of mitochondrial cardiolipin.Conclusions1.The lipid metabolic reprogramming is critically involved in cervical cancer radiation resistance.2.The increased mitophagy is the leading cause of improved mitochondrial function of radioresistant cervical cancer.3.CRLS1-mediated synthesis of mitochondrial cardiolipin induces mitophagy to support mitochodrial energy supply and protect cervical cancer cell from apoptosis under radiation challenge.