New Insights in Gene Expression Alteration as Effect of Paclitaxel Drug Resistance in Triple Negative Breast Cancer Cells

Triple negative breast cancer (TNBC) is a highly aggressive form of cancer which lacks targeted therapy options. Thus, TNBC patients have poor outcomes and a decreased survival rate than patients with other types of breast cancers. Due to the lack of surface receptors, TNBC needs a comprehensive investigation to provide more information regarding patient's therapy, as well as to understand the way how to counteract drug resistance mechanisms. Nowadays, chemotherapy remains an unsolved issue which rise a lot of questions in oncology field. In this article, we investigated the implication of paclitaxel in TNBC cell lines after a prolong administration, after 12, respectively 24 passages followed by evaluation of morphological alteration, mutational pattern by next generation sequencing and the altered gene expression pattern by microarray technology and validation by qRT-PCR of the resistance to therapy relevant genes. Using functional assays, we showed that paclitaxel exhibits antiproliferative activity on Hs578T/Pax and MDA-MB-231/Pax demonstrating the activation of cell death mechanisms. Confocal microscopy revealed significant modifications which occur in the morphological structure with a disruption of the actin-filaments and also mitotic catastrophe. The presence of these nuclear alterations is due to some modifications at the cellular and molecular levels. Important alterations at the transcriptomic and genomic levels were observed from this a common drug resistance signature (IL-6, CXCL8, VEGFA, EGR1, PTGS2 and TRIB1) for both cell lines at 24 passages was discovered. Also, an important mutation (TP53) linked with drug response was identified. These results might be used to furnish novel biomarkers in TNBC, as well as to find a strategy to counteract the resistance to therapy in order to increase survival rate and to enhance the prognosis of patients with TNBC.