The Role And Mechanism Of Octamer-binging Transcription Factor 1 On Epithelial To Mesenchymal Transition In Ovarian Cancer

Background and Aims: Octamer binding transcription factor 1(OCT1)is the first identified and widely expressed transcription factor in the POU domain,which is involved in regulating a variety of physiological and pathological processes in organisms.Current studies have shown that OCT1 can affect the drug resistance,therapeutic resistance and development of tumors by regulating a variety of signal pathways.The research group did some studies on the effect of OCT1 on ovarian cancer,but the effect of EMT on ovarian cancer and its molecular mechanism have not been studied.Methods: The clinical correlation between OCT1 and ovarian cancer was analyzed by TCGA,Kaplan-Meier Plotter platform and western blot.Ovarian cancer cells were infected with lentivirus to specifically inhibit or overexpress OCT1,and the effect of regulating OCT1 expression on EMT phenotype of many kinds of ovarian cancer cells was evaluated by transwell chamber migration and invasion experiments.Western blot assay was used to screen the EMT-related markers affected by OCT1 expression.At the same time,the target gene G0S2 directly regulated by OCT1 was screened by transcriptome sequencing,qRT-PCR verification,JASPER and Kaplan-Meier Plotter analysis.After the knockout and overexpression plasmids of G0S2 gene were successfully constructed,the effects of G0S2 gene on EMT phenotype of many kinds of ovarian cancer cells were verified by western blot,qRT-PCR and transwell chamber migration and invasion experiments.In addition,western blot assay was used to further verify the EMT-related markers affected by G0S2 expression.Results: The clinical correlation between OCT1 and ovarian cancer was analyzed by TCGA,Kaplan-Meier Plotter platform and western blot experiment.It was found that OCT1 was abnormally expressed in ovarian cancer cells,and the high expression of OCT1 was closely related to the poor prognosis of ovarian cancer.OVCAR8 and SKOV3 cells with relatively high OCT1 expression were selected for subsequent knockout experiments,while ES2 and OVCAR5 cells with relatively low OCT1 expression were used for subsequent overexpression experiments.Subsequent experiments found that regulating the expression of OCT1 significantly affected the EMT phenotype of ovarian cancer cells.Through western blot experiment,screening EMT-related marker molecules affected by OCT1 expression,it was found that OCT1 could significantly affect the expression of EMT-related marker molecule E-cadherin,as well as the expression of N-cadherin,Vimentin,MMP-2,Snail-1 and ERK1/2phosphorylation.In order to further study the potential molecular mechanism of OCT1 regulating ovarian cancer EMT,transcriptome sequencing,qRT-PCR verification,JASPER and Kaplan-Meier Plotter platform analysis of OCT1 showed that G0S2 gene is probably the target gene directly regulated by OCT1 and may participate in the regulation of OCT1 on ovarian cancer EMT.The knockout and overexpression plasmids of G0S2 gene were successfully constructed.After specific inhibition or overexpression of G0S2,it was found that the change of EMT expression could cause the change of EMT phenotype of ovarian cancer cells.In addition,regulating the expression of G0S2 significantly affected the expression of EMT related marker molecule E-cadherin,and affected the expression of N-cadherin,Vimentin,MMP-2,Snail-1 and the phosphorylation of ERK1/2,which was consistent with that of OCT1.These results suggest that OCT1 may regulate the expression of EMT-related markers through G0S2-mediated ERK signal pathway,and then affect the EMT process of ovarian cancer.Conclusion: This study shows that OCT1 is abnormally expressed in ovarian cancer cells,and the high expression of OCT1 is related to the poor prognosis of patients with ovarian cancer.In ovarian cancer cells,regulating the expression of OCT1 can significantly affect the EMT phenotype of many kinds of ovarian cancer cells.OCT1 may regulate the expression of key markers downstream of EMT through G0S2-mediated ERK signal pathway,and then participate in the EMT process of ovarian cancer.The results of this study are likely to provide new targets and treatment strategies for the diagnosis and treatment of ovarian cancer.