iTRAQ-based proteomics analysis reveals novel candidates for platinum resistance of epithelial ovarian cancer

Platinum-based chemotherapy is commonly used in the treatment of various cancers, including epithelial ovarian cancer (EOC). However, in EOC, chemotherapy failure is mainly caused by platinum resistance. In this present study, we aimed to identify novel biomarkers for predicting platinum chemosensitivity. Fresh specimens of 16 serous high-grade ovarian cancer (HGSC) cases were collected during cytoreductive surgery. Isobaric tags were used to identify differentially expressed proteins in platinum-resistant samples (n = 8) and platinum-sensitive samples (n = 8). Compared to platinum-sensitive samples, 741 significantly differentially expressed proteins were detected, of which 325 were upregulated and 416 were downregulated. To validate the isobaric tags for relative and absolute quantification (iTRAQ) method, western blotting was performed on two upregulated proteins, angiomotin-like protein 1 (AMOTL1) and Lumican. The results showed that platinum-resistant tumor samples expressed significantly higher levels of AMOTL1 and Lumican than platinum-sensitive tumor samples. Altogether, we identified candidate proteins related to platinum resistance in ovarian cancer. Both AMOTL1 and Lumican seem to be promising biomarkers that could distinguish between platinum-resistant and platinum-sensitive EOC.