DHODH Inhibition Exerts Synergistic Therapeutic Effect with Cisplatin to Induce Ferroptosis in Cervical Cancer through Regulating mTOR Pathway

SIMPLE SUMMARY: Ferroptosis exhibits potent antitumor ability and dihydroorotate dehydrogenase (DHODH) has recently been identified as a novel ferroptosis defender independently of GPX4 or FSP1. DHODH has been studied in several diseases including oral squamous cell carcinoma and small cell lung cancer. This study demonstrates that DHODH inhibition inhibits cervical cancer cells’ cell proliferation and induces cell death through ferroptosis. Moreover, the combination of DHODH inhibition and cisplatin synergistically inhibits the growth of cervical cancer cells in vitro and in vivo by ferroptosis via the mTOR pathway. ABSTRACT: Ferroptosis exhibits a potent antitumor effect and dihydroorotate dehydrogenase (DHODH) has recently been identified as a novel ferroptosis defender. However, the role of DHODH inhibition in cervical cancer cells is unclear, particularly in synergy with cisplatin via ferroptosis. Herein, shRNA and brequinar were used to knock down DHODH and directly inhibit DHODH, respectively. Immunohistochemistry and Western blotting assays were performed to measure the expression of proteins. CCK-8 and colony formation assays were employed to assess the cell viability and proliferation. Ferroptosis was monitored through flow cytometry, the malondialdehyde assay kit and JC-1 staining analyses. The nude mouse xenograft model was generated to examine the effect of combination of DHODH inhibition and cisplatin on tumor growth in vivo. The expression of DHODH was increased in cervical cancer tissues. DHODH inhibition inhibited the proliferation and promoted the ferroptosis in cervical cancer cells. A combination of DHODH inhibition and cisplatin synergistically induced both in vitro and in vivo ferroptosis and downregulated the ferroptosis defender mTOR pathway. Therefore, the combination of DHODH inhibition and cisplatin exhibits synergistic effects on ferroptosis induction via inhibiting the mTOR pathway could provide a promising way for cervical cancer therapy.