Fig. 1

Untreated tumors contain chemotherapy-resistant quiescent cells with an EMT/stemness phenotype and increased ZEB2 levels. a SW480 cells were stained with PKH26, treated with 2,5 μM oxaliplatin (OXA) at day 11 and monitored by flow cytometry. FACS plots are shown in Additional file 4. b FACS plots showing PKH26 positivity in CCSCs-derived tumors the day of injection (Day 0) and at 1/3/6 weeks. c Percentage of PKH26⁺ cells (black line) in relation to tumor size (red line). Mean ± SD or SEM (tumors), n = 6 tumors/group. d Spatial representation of principal component (PC) analysis with genes as rows (statistical units) and samples as columns (variables). n = 5 samples of 2 pooled tumors each. e Numerical PC plot identifying genes with the highest absolute score in the discriminant component. A full list of transcripts modulated in PKH26⁺ versus PKH26⁻ cells is reported in Additional file 5. f Categories of transcripts enriched in PKH26⁺versus PKH26⁻ cells. Replicated entries are reported in Materials and Methods. Transcripts categories are detailed in Additional file 6. g qRT-PCR analysis of ZEB2 in EpCAM⁺/PKH26⁺ versus EpCAM⁺/PKH26⁻ cells from CCSCs-derived xenografts. *P < 0.05 (two-tailed t test), mean ± SD, n = 3 pools of 6 tumors each. h qRT-PCR of ZEB2 expression in SW480 cells untreated (day 0) or treated with 2,5 μM oxaliplatin (OXA). Mean ± SD of 3 experiments. i Representative confocal image of CCSCs-derived xenograft sections showing overlapping areas of ZEB2 (red) and PKH26⁺ (yellow) positivity. Scale bar 80 μm. l qRT-PCR of xenograft-derived EpCAM⁺/PKH26⁺ versus EpCAM⁺/PKH26⁻ cells. *P < 0.05, **P < 0.01 and ***P < 0.001 (two-tailed t test). Mean ± SD, n = 3 pools of 6 CCSCs-derived tumors each. m qRT-PCR analysis of ZEB2 expression in TOP-GFP.mcherry negative (grey) and positive (purple) CCSCs sorted from in vitro culture. Mean ± SD of 3 experiments