Folic Acid Metabolism Enzyme MTHFR Inhibits Ferroptosis By Downregulating HMOX1 Ubiquitination In Ovarian Cancer

Background:Ovarian cancer is a gynecological malignant tumor with high lethality and the increasing of incidence and mortality year by year.At present,interval debulking surgery and chemotherapy are the most commonly used methods for the treatment of ovarian cancer.Due to the lack of precise biomarkers and obvious symptoms of early-stage ovarian cancer,most patients are diagnosed at late stages,which resulting in a5-year relative survival rate less than 50%.In addition,the decreasing sensitive of ovarian cancer to chemotherapy drugs leading to the poor prognosis of patients.Therefore,it is of great significance to find biomarkers with strong specificity and high sensitivity for the diagnosis and treatment of ovarian cancer.A number of studies have shown that folic acid metabolism enzyme MTHFR is closely related to the occurrence,development,drug sensitivity and prognosis of ovarian cancer.However,the specific role and mechanism of MTHFR in ovarian cancer remain unclear.Objective:In this study,we discussed the biological functions and mechanisms of MTHFR in ovarian cancer in order to provide new potential targets for the diagnosis,treatment and prognosis of ovarian cancer.Methods:Bioinformatics,q PCR,Western blot and IHC were used to analyze the expression of MTHFR in ovarian cancer and the correlation between MTHFR and clinical characteristics of ovarian cancer patients.The effects of MTHFR expression on the proliferation,growth and drug sensitivity of ovarian cancer cells were analyzed by colony formation and CCK8 assay using MTHFR knockdown ovarian cancer cell lines.The downstream pathway and target molecular of MTHFR were identified by protein mass spectrometry.CCK8 assay and molecular kit detection were used to analyze the effect of MTHFR expression on downstream pathway.The functions of target molecular in ovarian cancer were explored by colony formation and CCK8 assay,and the correlation between MTHFR and target molecular was analyzed by ovarian cancer tissue microarray.The interaction between MTHFR and HMOX1 and TRC8 was detected by Co-IP assay.The effect of MTHFR on HMOX1 ubiquitination was tested by Western blot.Finally,the influence of MTHFR expression on tumorigenicity of ovarian cancer cells was analyzed by in vivo animal experiments.Results:The expression of MTHFR was upregulated in ovarian cancer,and its expression level was positively associated with the prognosis of ovarian cancer patients.Knockdown of MTHFR could inhibit the proliferation and growth of ovarian cancer cells and enhance the drug sensitivity of tumor cells.Knockdown of MTHFR could upregulate the levels of Fe²⁺,MDA and ROS in ovarian cancer cells and promote ferroptosis in tumor cells.HMOX1 was the downstream target molecular of MTHFR,which mediated the function of MTHFR.The expression level of MTHFR and HMOX1 were positively correlated in ovarian cancer tissue microarray,and the upregulation of the two molecular predicted the poor prognosis of ovarian cancer patients.Knockdown of MTHFR increased the interaction of TRC8 to HMOX1 and promoted the K48 ubiquitination of HMOX1.Knockdown of MTHFR inhibits the tumorigenicity of ovarian cancer cells in nude mice.Conclusion:In summary,this study demonstrates that MTHFR promotes the development of ovarian cancer via suppression of ferroptosis,which is related to inhibiting the interaction of TRC8 to HMOX1,improving the protein stability of HMOX1.Therefore,MTHFR and HMOX1 are potential therapeutic targets for ovarian cancer.