Clinical implications of REST and TUBB3 in ovarian cancer and its relationship to paclitaxel resistance

The objective of this study was to examine the expression levels of RE1-silencing transcription factor (REST) and class III β-tubulin (TUBB3) in ovarian cancer and to determine if there is a correlation between their expression and resistance to chemotherapy in ovarian cancer. The protein expression of REST and TUBB3 in ovarian cancer was detected by Western blot analysis. REST expression was inhibited by small interfering ribonucleic acid (siRNA) in human ovarian cancer cell lines. The levels of REST and TUBB3 protein expression were detected by immunohistochemistry. The relationship between REST and TUBB3 expression and chemotherapy resistance, clinicopathological parameters, and prognosis of ovarian cancer was then determined. The present study found that REST was more highly expressed in the ovarian SKOV3 carcinoma cell line compared to the paclitaxel-resistant ovarian cancer cell line, SKOV3/TAX ( P = 0.01). In contrast, TUBB3 was more highly expressed in SKOV3/TAX cells compared to SKOV3 cells ( P = 0.01). After REST siRNA interference, TUBB3 expression increased in SKOV3 cells. REST expression was significantly higher in the paclitaxel-sensitive group compared to the paclitaxel-resistant group (70.7 % vs. 37.0 %, P < 0.05). However, TUBB3 expression was significantly lower in the paclitaxel-sensitive group compared to the paclitaxel-resistant group (47.6 % vs. 77.8 %, P < 0.05). Notably, REST was more highly expressed in TUBB3-negative cases than TUBB3-positive cases ( P < 0.05). Univariate analyses indicated that both REST and TUBB3 expression were unrelated to tumor differentiation, histological type, and clinical stage (all P > 0.05). According to the Cox regression model, negative REST and positive TUBB3 protein expression was detected as independent prognostic factors ( P = 0.003 and P = 0.005, respectively). REST and TUBB3 protein may be potential biomarkers for chemoresistance and prognosis in ovarian cancer.