Ceramide synthase 6 predicts poor prognosis and activates the AKT/mTOR/4EBP1 pathway in high-grade serous ovarian cancer

Am J Transl Res. 2020 Sep 15;12(9):5924-5939. eCollection 2020.

Abstract

Objective: Ovarian cancer is one of the most common gynecological malignancies worldwide, and its mortality rate ranks first among gynecologic cancers. Ceramide synthases are closely related to cancer development. In this study, we investigated the role of ceramide synthase 6 (CerS6) in the development of serous ovarian cancer. Methods: Expression of CerS6 in cancerous and healthy ovarian tissue was assessed by database analysis and immunohistochemistry. The biological role of CerS6 in serous ovarian cancer cells was assessed by CerS6 knockdown followed by cell counting, colony formation, transwell migration, wound healing, and flow cytometry assays and measurement of tumor proliferation in nude mice. Signaling pathway components were analyzed by Western blotting. Gene enrichment was analyzed by GSEA and R, and RNA sequencing was used to compare the transcriptomes of serous ovarian cancer cells with and without CerS6 knockdown. Results: High CerS6 expression in ovarian cancer tissues was closely related to poor prognosis. Knockdown of CerS6 inhibited serous ovarian cancer cell proliferation, invasion, and metastasis and promoted their apoptosis. In addition, CerS6 knockdown increased the proportion of serous ovarian cancer cells in G2/M phase. CerS6 regulates cell cycle through the AKT/mTOR/4EBP1 signaling pathway, which affects cell proliferation and metastasis. The GSEA, R, and RNA sequencing analyses showed that knocking down CerS6 significantly affects cell cycle in serous ovarian cancer cells. Conclusions: CerS6 may have an oncogenic role in ovarian cancer and may represent a new prognostic marker and therapeutic target for serous ovarian cancer.

Keywords: AKT/mTOR/4EBP1 signaling pathway; CerS6; High-grade serous ovarian cancer; cell cycle.