Relationship between expressions of Notch1 and drug resistance of breast carcinoma

Abstract

Objective To investigate the role of Notchl in the chemotherapy process of breast cancer by studying the the efficiency of mammosphere formation, the ratio of stem cells in MCF-7 and MCF-7/ADR, and the expression status of Notchl in MCF-7, MCF-7/ADR and stem cells respectively. Methods Real time fluorescent quantitative reverse transcriptase polymerase chain reaction （RT-qPCR） and Western blotting were employed to detect the expression status of Notchl in breast cancer cell lines MCF-7, MCF-7/ADR and ALDH1 ＋/CD44 ＋/CD24- breast cancer stem cells （BCSCs）. Serum-free me- dium was available to assess the efficiency of mammosphere formation. Flow cytometry was used to define the ratio of BCSCs and select them in MCF-7 and MCF-7/ADR. Results The expression status of Notchl [ （0. 0748±0. 0043 ） vs （0. 0461±0. 0022 ）, P 〈 0.05 ] and the ability of mammosphere formation were significantly higher in MCF-7/ADR than in MCF-7 （P 〈 0. 05）. There was significant difference in the ra- tio of BCSCs between MCF-7/ADR and MCF-7 （ 11.40% vs 1.89% ）. Furthermore the expression score of Notchl in BCSCs was significantly higher than in non-BCSCs [ （0. 3096±0. 0324 ） vs （0. 0428 ±0. 0061 ）, P 〈 0.05 ]. Conclusion The high level expression of Notchl in breast cancer and BCSCs suggests regulating Notchl may play an important role in reversing chemotherapy resistance of breast cancer. Key words: Breast neoplasm; Stem cell; Notchl