BACKGROUNDRecent studies indicate that S100P expression may be a biomarker that can predict the success of cancer chemotherapy. Whether it is relevant to chemotherapeutics in ovarian cancer is unknown. In this study, we investigated the association of S100P expression with paclitaxel sensitivity in ovarian cancer cell lines.

METHODSWe measured S100P expression and paclitaxel resistance profiles in parent SKOV3 and OVCAR3 cell lines. Then, the two cell lines were transiently transfected with S100P siRNA. We also constructed an OVCAR3 cell clone that stably overexpressed S100P. The effect of S100P expression level on the survival of cells exposed to paclitaxel was measured using the MTT assay. S100P expression was evaluated by semi-quantitative RT-PCR and Western blotting. Significance of differences was calculated using independent samples t-test and one way analysis of variance (ANOVA).

RESULTSLower S100P expression was associated with a survival advantage in OVCAR3 cells exposed to paclitaxel; the survival advantage in SKOV3 cells was smaller (P < 0.05). The survival advantage associated with decreased S100P expression was even greater for SKOV3 and OVCAR3 cells that had been transfected with S100P siRNA before being exposed to paclitaxel (P < 0.05). Consistent with this, the OVCAR3 cell clone that was transfected to overexpress S100P was more sensitive to paclitaxel (P < 0.05).

CONCLUSIONSLow S100P expression contributes to drug resistance to paclitaxel in ovarian cancer cell lines. S100P expression thus might be a marker that can predict the effectiveness of paclitaxel based chemotherapy. Such a marker could be helpful in improving individual medication regimens for ovarian cancer patients.