The role of miR-26a and miR-30b in HER2+ breast cancer trastuzumab resistance and regulation of the CCNE2 gene
AbstractA subset of HER2+ breast cancer patients manifest clinical resistance to trastuzumab. Recently, miR-26a and miR-30b have been identified as trastuzumab response regulators, and their target gene CCNE2 seems to play an important role in resistance to trastuzumab therapy. Cell viability was evaluated in trastuzumab treated HER2+ BT474 wt (sensitive), BT474r (acquired resistance), HCC1954 (innate resistance), and MDA-MB-231 (HER2−) cell lines, and the expression of miR-26a, miR-30b, and their target genes was measured. BT474 wt cell viability decreased by 60% and miR-26a and miR-30b were significantly overexpressed (~3-fold, p = 0.003 and p = 0.002, respectively) after trastuzumab trea…
The role of AXL as mechanism of resistance to trastuzumab and a prognostic factor in breast cancer HER2 positive: A translational approach
Abstract Background Breast cancer (BC) is a heterogeneous disease. HER2+ BC represents between 15-30% of cases. Trastuzumab (T), a monoclonal antibody, has been successfully improved clinical benefits in both adjuvant and in metastatic settings. Despite this evidence, many patients experience resistance to therapy. The objective of this study is to assess AXL as a potential mechanism of resistance and its implication as a prognostic factor. Methods We used three cell lines with acquired resistance to T. Resistant models were generated by treating parental cells (AU565, SKR3, BT474) with constant dose of T (15mg/mL) for 6 months. Cell viability was estimated by MTT assay. Proteins were asses…
Recent Insights into the Development of Preclinical Trastuzumab- Resistant HER2+ Breast Cancer Models.
Background: Overexpression and amplification of the human epidermal growth factor receptor 2 (HER2) occur in 20% of total breast carcinomas. HER2-overexpression is implicated in disease initiation and progression and associated with poor prognosis. Trastuzumab, a humanized monoclonal antibody, is the standard HER2-targeted therapy for early and metastatic HER2-amplified breast cancer patients. Trastuzumab has significantly increased clinical benefit in HER2+ metastatic and adjuvant settings; however, it is not effective for many patients due to primary or acquired resistance to the drug. During the last decade, many studies have revealed a number of novel molecular traits of HER2+ breast c…
Autocrine CCL5 Effect Mediates Trastuzumab Resistance by ERK Pathway Activation in HER2-Positive Breast Cancer.
Abstract HER2-positive breast cancer is currently managed with chemotherapy in combination with specific anti-HER2 therapies, including trastuzumab. However, a high percentage of patients with HER2-positive tumors do not respond to trastuzumab (primary resistance) or either recur (acquired resistance), mostly due to molecular alterations in the tumor that are either unknown or undetermined in clinical practice. Those alterations may cause the tumor to be refractory to treatment with trastuzumab, promoting tumor proliferation and metastasis. Using continued exposure of a HER2-positive cell line to trastuzumab, we generated a model of acquired resistance characterized by increased expression …