OBJECTIVE: Although the advent of chemotherapy has made some progress in the comprehensive treatment of breast cancer, drug resistance of tumor cells remains to be one of the main challenges for the treatment of breast cancers. Several microRNAs have been implicated in the resistant process, but the role of miR-130a in drug resistance in breast cancer remains unclear. The present study aims to investigate the role and mechanisms of miR-130a in drug resistance in breast cancer cells and tissues. PATIENTS AND METHODS: miR-130a mimics was used to up-regulate miR-130a expression in Doxorubicin-resistant MCF-7/Adr breast cancer cell line, followed by MTT assay and colony formation to determine cell viability and relative colony number. The relationship between the expression of miR-130a and drug resistance was detected by in situ hybridization in the formalin-fixed paraffin-embedded (FFPE) tissues from 50 breast cancer patients before and after Epirubicin-based neoadjuvant chemotherapy. RESULTS: Up-regulation of miR-130a level in MCF-7/Adr cells decreased the cell viability and colony number, and reversed Doxorubicin resistance of MCF-7/Adr cells. In breast cancer tissue from patients, the miR-130a level was lower before neoadjuvant chemotherapy than that after neoadjuvant chemotherapy (P < 0.05). Moreover, a significant increase in the expression of miR-130a was observed in breast tumor tissues from patients sensitive to neoadjuvant chemotherapy compared to the patients who were resistant to neoadjuvant chemotherapy (P < 0.05). CONCLUSION: We concluded that miR-130a might weaken drug resistance of human breast cancer cells, and act as an important factor in prediction of therapeutic responses in chemotherapy of breast cancer. IJCEP
OBJECTIVE: Although the advent of chemotherapy has made some progress in the comprehensive treatment of breast cancer, drug resistance of tumor cells remains to be one of the main challenges for the treatment of breast cancers. Several microRNAs have been implicated in the resistant process, but the role of miR-130a in drug resistance in breast cancer remains unclear. The present study aims to investigate the role and mechanisms of miR-130a in drug resistance in breast cancer cells and tissues. PATIENTS AND METHODS: miR-130a mimics was used to up-regulate miR-130a expression in Doxorubicin-resistant MCF-7/Adr breast cancer cell line, followed by MTT assay and colony formation to determine cell viability and relative colony number. The relationship between the expression of miR-130a and drug resistance was detected by in situ hybridization in the formalin-fixed paraffin-embedded (FFPE) tissues from 50 breast cancerpatients before and after Epirubicin-based neoadjuvant chemotherapy. RESULTS: Up-regulation of miR-130a level in MCF-7/Adr cells decreased the cell viability and colony number, and reversed Doxorubicin resistance of MCF-7/Adr cells. In breast cancer tissue from patients, the miR-130a level was lower before neoadjuvant chemotherapy than that after neoadjuvant chemotherapy (P < 0.05). Moreover, a significant increase in the expression of miR-130a was observed in breast tumor tissues from patients sensitive to neoadjuvant chemotherapy compared to the patients who were resistant to neoadjuvant chemotherapy (P < 0.05). CONCLUSION: We concluded that miR-130a might weaken drug resistance of humanbreast cancer cells, and act as an important factor in prediction of therapeutic responses in chemotherapy of breast cancer. IJCEP
Authors: Nicolas Magné; Rémy Largillier; Pierre-Yves Marcy; Jacques Magné; Moïse Namer Journal: Support Care Cancer Date: 2005-03-30 Impact factor: 3.603