Inhibition of XIAP increases carboplatin sensitivity in ovarian cancer.

Carboplatin is a first-line treatment for ovarian cancer. However, most patients develop resistance and undergo disease recurrence. This study aims to explore the relationship between the expression of X-linked inhibitor of apoptosis protein (XIAP) and carboplatin sensitivity in ovarian cancer. We examined the expression of XIAP in ovarian cancer by immuno-chemistry. Next, we investigated the role of XIAP in regulating carboplatin sensitivity in ovarian cancer ES2 and 3AO cells through Cell Counting Kit-8 cell viability assay and fluorescein isothiocyanate-Annexin V/propidium iodide apoptosis assay. Expression of apoptotic effectors was measured by Western blot. The immunochemistry results showed that high XIAP expression levels inversely correlated with carboplatin response (P=0.03) and progression-free survival (P=0.0068) in patients with ovarian cancer. Knockdown of XIAP repressed the cell viabilities in the carboplatin-treated cells and increased carboplatin-induced caspase activation. In summary, our data show that XIAP mediates carboplatin sensitivity of ovarian cancer. In summary, our data show that XIAP mediates carboplatin sensitivity of ovarian cancer and XIAP may be a novel target for the treatment of carboplatin-resistant ovarian cancer.