Mitogen-Activated Protein Kinase 15 Is a New Predictive Biomarker and Potential Therapeutic Target for Ovarian Cancer.

Mitogen-activated protein kinase 15 (MAPK15) has been reported to be associated with several cancers. This study aimed to explore for the first time on the relationship between MAPK15 expression and cancer progression/drug responsiveness in ovarian carcinoma. To this end, MAPK15 expression level was examined by immunohistochemistry (IHC) staining of an ovarian tissue array (10 normal and 70 malignant samples). Drug sensitivity of ovarian cancer cell lines (including OVCAR3 and SKOV3) was measured by MTS assay. The modulation of MAPK15 expression in OVCAR3 and SKOV3 was verified by immunoblot and real-time PCR analyses. The prognostic value of MAPK15 in ovarian cancer patients was assessed using the Kaplan-Meier Plotter database and Gene Expression Omnibus (GEO) datasets. The IHC results showed that MAPK15 expression was negatively associated with tumor grade, TNM stage, tumor size, and regional lymph node metastasis of ovarian carcinoma. Importantly, overexpressing MAPK15 increased cisplatin toxicity in ovarian carcinoma cells and online database analysis indicated that patients with high MAPK15 expression had favorable prognosis with/without chemotherapy. Taken together, our results indicate that a decreased MAPK15 expression is associated with advanced-stage ovarian cancer and unfavorable survival outcomes. MAPK15 may be a new biomarker for ovarian cancer, and the encouraging therapeutic strategy would be found by combining the regulation of MAPK15 expression.