Overexpression of transmembrane protein 102 implicates poor prognosis and chemoresistance in epithelial ovarian carcinoma patients.

Most ovarian cancer patients experience disease recurrence and chemotherapeutic resistance, and the underlying mechanisms are unclear. Identifying relevant pathways could reveal new therapeutic targets. Here we examined expression of transmembrane protein 102 (TMEM102), a biomarker of prognosis and chemoresistance, in epithelial ovarian cancer (EOC), and assessed its role in inhibiting tumor cell apoptosis. We performed qRT-PCR to investigate the association of TMEM102 expression with clinical outcomes in 226 EOC patients. We also conducted studies to explore possible mechanisms through which TMEM102 may influence chemoresistance, including the effects of downregulating TMEM102 expression with small interfering RNA. Serous and high-grade carcinomas expressed significantly higher TMEM102 than normal ovarian tissues. TMEM102 was also overexpressed in patients with advanced-stage disease and chemoresistance. Reduction of TMEM102 expression by small interfering RNA induced ovarian cancer cell apoptosis after cytotoxic treatment. TMEM102 overexpression enhanced chemoresistance via upregulation of heat shock proteins 27, 60, and 70; and survivin, resulting in decreased cytochrome c in the mitochondria and decreased caspase 9 expression. Our results indicate that TMEM102 overexpression may promote chemoresistance via inhibition of a mitochondria-associated apoptotic pathway.