The miR-200 family controls β-tubulin III expression and is associated with paclitaxel-based treatment response and progression-free survival in ovarian cancer patients

Ovarian cancer remains one of the leading causes of cancer deaths. Thus, new biomarkers predictive of response to the standard paclitaxel-carboplatin treatment are needed to improve chemotherapy strategies. MicroRNAs have the potential to modify drug outcomes. Based on this, we have demonstrated in this study that patients with a high expression of the miR-200 family show low levels of beta-tubulin class III in ovarian carcinoma. In addition, we have established the clinical relevance of these microRNAs for ovarian cancer patients' treatment response and survival. In a well-characterized series of 72 ovarian carcinomas, the expressions of miR-141, miR-200a, miR-200b, miR-200c, and miR-429 were quantified by quantitative reverse transcription-PCR, and the protein content of beta-tubulin isotypes I, II, and III was determined by immunohistochemistry. The relationship between these microRNAs, beta-tubulin expression, response to paclitaxel-based treatment, progression-free survival (PFS) and overall survival was determined. While isotype I had constant high levels, protein expression of beta-tubulins II and III was mutually exclusive. Low tumoral miR-200 expression was significantly associated with high beta-tubulin III protein content (P values range, 0.047-<0.0001), and patients without complete response (CR) had lower miR-200c levels than patients with CR (hazard ratio (HR)=1.43, 95% confidence interval (CI)=1.02-1.99, P=0.037, multivariate analysis). Additionally, low miR-200 family expression had a trend toward poor PFS (HR>2.0, P values 0.051, 0.054, and 0.079 for miR-200c, miR-141, and miR-429 respectively, multivariate analysis). In conclusion, miR-200 family members affect the final beta-tubulin III protein content of ovarian carcinomas. Furthermore, these microRNAs might constitute the biomarkers of response to paclitaxel-based treatments and relapse/progression of advanced stage ovarian carcinoma patients.