Fig. 5

Drug sensitivity, DNA repair, and cycling profile of CiSCs. a, b CiSCs, parental BM-MSCs, and MCF7 and Hela control cells were exposed to increasing concentrations of cisplatin (a) or doxorubicin (b) for 24 hours. Cell viability determined by Annexin-V-FITC and PI apoptosis detection kit. CiSCs showed highly more significant resistant to cisplatin and doxorubicin than parental BM-MSCs (P < 0.05). c, d Percentage of Annexin-V-positive cells in MCF7, Hela, and HepG2 CiSCs, parental BM-MSCs, and MCF7 and Hela control cells upon exposure to increasing concentrations of cisplatin (c) or doxorubicin (d) for 24 hours, indicating that CiSCs exhibit significantly decreased apoptosis compared to parental BM-MSCs and control cancer cells (P < 0.05). Data presented as mean ± SD. e Real-time qRT-PCR analysis of Bcl-2 (anti-apoptotic protein) and Bax (pro-apoptotic molecule), indicating significantly increased expression of Bcl-2 and reduced expression of Bax in MCF7, Hela, and HepG2 CiSCs compared to parental BM-MSCs (P < 0.05). β-actin mRNA used to normalize variability in template loading. Data reported on a log-10 scale as mean ± SD. f CiSCs, parental BM-MSCs, and MCF7 and Hela control cells analyzed for their cell cycle profile and % population in G1/G0, S, and G2/M phases presented graphically. CiSCs appeared to show cell cycle arrest in the G2/M phase and have a slower cell cycle progress than their parental BM-MSCs. g CiSCs, parental BM-MSCs, and MCF7 and Hela control cells treated with increasing concentrations of cisplatin and presence of DNA damage assessed by single-cell gel electrophoresis assay under alkaline conditions (alkaline Comet assay). The average tail moment quantified showed CiSCs display significantly less DNA damage response upon exposure to increasing concentrations of cisplatin (P < 0.05). Data presented as mean ± SD. h Expression level of mRNA encoding poly-ADP-ribose polymerase (PARP), an essential protein involved in DNA repair, relative to parental BM-MSCs as determined by real-time qRT-PCR. Data reported on a log-10 scale as mean ± SD. BM-MSC bone marrow mesenchymal stem cell, CiSC cancer-induced stem cell