Effect of doxorubicin on viability and Bax, Bcl-2, p53, Nanog, Sox-2, Oct-4 gene expressions in MCF-7 stem-like cells

Abstract

Abstract Background: The aim of this study is to clarify whether cell viability, cell death, and gene expressions pertaining to self-renewal and pluripotency differ in doxorubicin (DOX) [IC50] treated and untreated human MCF-7 mammalian cancer cells as well as between their CD44+/CD24¯/low cancer stem cells (CSC). Methods: Non-tumorigenic human MCF-10A mammalian cells and their CD44+/CD24¯/low stem cells were used as the control. Cell viability, apoptosis, necrosis and cell death were studied by flow cytometry. Cell death pathways, multidrug resistance, pluripotency and self-renewal were studied at Nanog, Oct-4, Sox-2, p53, Bcl-2 and Bax mRNA gene expression level by qRT-PCR. Results: IC50 value for DOX treated MCF-7 cells was found to be 3.73 µM. Bax, Bcl-2, p53 genes were down-regulated while Nanog, Oct-4, Sox-2 genes were up-regulated in DOX [IC50] treated MCF-7 CSCs. Bax, p53, Nanog, Oct-4 genes were down-regulated while Sox-2, Bcl-2 genes were up-regulated in DOX [IC50] untreated MCF-7 CSCs. Discussion: In addition to literature reports on DOX [IC50] treated non-stem MCF-7 cells undergoing autophagy and DOX [IC50] treated dedifferentiated MCF-7 (CD44+/CD24¯/low) cancer stem-like cells undergoing apoptosis, our laboratory data strongly suggest that DOX [IC50] treated MCF-7 CSCs also undergo necrosis as determined by flow cytometry and necroptosis due to downregulation of Bax, Bcl-2 and p53 genes. Conclusion: Our finding suggests that multiple types of cell death pathways, including apoptosis, necrosis and necroptosis, is involved in DOX [IC50] treated MCF-7 CSCs. DOX [IC50] treated MCF-7 CSCs become pluripotent with self-renewal capability by up-regulation of Nanog, Oct-4, Sox-2 gene expressions to possibly survive necroptosis. Nanog, Oct-4, Sox-2 gene expressions are all down-regulated in DOX [IC50] treated MCF-10A (CD44+/CD24¯/low) stem cells, disabling the self-renewal and pluripotency features.