Influence of paclitaxel therapy on expression of ßIII-Tubulin and Carbonic anhydrase IX proteins in chemically-induced rat mammary tumors

The manuscript is focused on analyze of βIII-Tubulin and Carbonic anhydrase IX proteins in experimental model of chemically induced rat mammary tumors. Overexpression of class III β-tubulin, a factor that confers dynamic properties to microtubules, is a candidate tumor biomarker for resistence to microtubule - targeting therapy in many solid tumors, including breast cancer. The expression of CAIX protein in malignant tumors plays an important role in progression of primary tumors and also contributes to increase risk of metastases. Nineteen rat females were used in this study. Mammary tumors were induced by 7,12 dimethylbenz(a)anthracene (DMBA). Rats were divided into two groups, group treated by paclitaxel and non-treated (control) group that was administered physiological solution. According to the tumor stage, they were subdivided into carcinoma in situ (CIS) and invasive carcinoma (IC). To detect the expression of both proteins, we used immunohistochemical staining (IHC). The ELISA method was used to detect the protein level in blood. The expression of CAIX and ßIII-tubulin increased significantly not only in mammary tumors, but also in blood of treated groups examined by ELISA method (p < 0.05). Additionally, the results revealed significant increase in the expression of ßIII-tubulin in IC samples and CAIX in CIS samples, when we compared treated to non-treated groups (p < 0.05). Paclitaxel-induced ßIII-tubulin and CAIX overexpression in mammary tumors and their increase in tissue and serum should indicate drug-induced increase of resistance. The potential benefits of this finding is still uncertain, but our findings can contribute to newly developing diagnostic opportunities and therapy of the mammary tumors.