Expression of cancer and CSC markers in CiSCs and side population (SP) properties of CiSCs. a Expression levels of mRNAs encoding KRAS, HER2, CDK4, BRCA2, E2F3, SMAD7, ABCB1, APC, and TP53 in MCF7, Hela, and HepG2 CiSCs relative to the parental BM-MSCs determined by real-time qRT-PCR. b Real-time qRT-PCR analysis of CSC marker genes. β-actin mRNA used to normalize variability in template loading. Data reported on a log-10 scale as mean ± SD. c Flow cytometry plots for cell surface markers CD44 and CD24 in BM-MSCs and MCF7, Hela, and HepG2 CiSCs. Gating set to unstained control cells. d Flow cytometry overlay histogram analysis of CD24 expression in BM-MSCs and MCF7, Hela, and HepG2 CiSCs. e Confocal immunofluorescence images for ALDH1A1 (green) of control BM-MSCs and MCF7, Hela, and HepG2 CiSCs. Nuclei stained with DAPI (blue). Scale bars = 60 μM. f Confocal immunofluorescence images for β-catenin (green) of control BM-MSCs and MCF7, Hela, and HepG2 CiSCs. Nuclei stained with DAPI (blue). Scale bars = 60 μM. g, h Flow cytometry overlay histogram analysis of (g) ALDH1A1 and (h) β-catenin in BM-MSCs and MCF7, Hela, and HepG2 CiSCs. For comparison, isotype control (black) used to define the positive and negative population for each marker. i, j Quantification of percentage of (i) ALDH1A1-positive and (j) β-catenin-positive cells compared to parental BM-MSCs by intracellular flow cytometry staining. Proportions of positive cells measured by subtracting control parental BM-MSCs staining from test histograms using super-enhanced Dmax (SED) normalized subtraction using FlowJo v. 10.2 software. Data presented as mean ± SD. k Hoechst-positive staining of BM-MSCs and Hoechst-negative SP cells from MCF7, Hela, and HepG2 CiSCs. Arrows indicate small population of Hoechst-positive (MP) cells within the SP cells. l Higher power view of Hoechst-positive BM-MSCs, higher power view of a SP cell, and higher power view of Hoechst-positive (MP) CiSCs. BM-MSC bone marrow mesenchymal stem cell, CiSC cancer-induced stem cell, MP major population