Drug sensitivity research of mTOR inhibitor on breast cancer stem cells
Liu, Y.; Zhang, X.; Liu, P.; Zhang, J.
Zhonghua Yi Xue Za Zhi 95(24): 1910-1914
2015
ISSN/ISBN: 0376-2491 PMID: 26710692 Document Number: 683185
To test the antitumor effects of the mTOR inhibitor everolimus in breast cancer stem cells and total cells in vitro and in vivo. In vitro studies, we sorted ESA⁺ CD44⁺ CD24(-/low) cells as stem cells using flow cytometry from primary breast cancer cells. Apoptosis and the cell cycle distributions of stem cells were examined by flow cytometry. The tumorigenicity of stem cells after treatment was investigated by soft agar colony formation assays. BALB/c mice were injected with stem cells and the different treatments were administered. After necropsy, the expression of Ki67, CD31, AKT1, and phospho-AKT (Thr308) was analyzed by immunohistochemistry. Treatment with everolimus resulted in growth inhibition of all stem cells in a dose-dependent manner. An increase in G0-G1 cell cycle arrest and an increased population of cells in early apoptosis were seen in everolimus treatment. In vivo, the volumes of the xenograft tumors significantly decreased in everolimus alone group compared to control group. Everolimus could inhibit the growth of both total breast cancer cells and sorted stem cells in vitro and in vivo.