a FTO protein level is the lowest in Circulating Tumor Cell lines. FTO protein level quantification by western blot in several patient derived cell lines from distinct origin: primary tumor, blood, and metastasis. The first graph represents the level of FTO protein in each individual cell lines. The following bar plot represents the quantification by groups. Mean ± S.E.M of four biological replicates, **p-value < 0.01, *p-value < 0.05, one-way anova followed by multiple comparison. b FTO mRNA level barely fluctuates throughout colon cancer progression. Level of FTO mRNA was evaluated by RT-PCR in the same cell lines as in a. Left graph represents of FTO level in each individual cell line. Right bar plot represents the quantification by groups. Mean ± S.E.M of three biological replicates, ns not significant, One way anova. c Increase of FTO level decreases the sphere forming potential of CTC cell lines. Cell growth and sphere forming potential evaluation after overexpression of FTO in CTC44 and CTC45 lines. d Increase of FTO level sensitizes CTC cell lines to chemotherapy. FIRI toxicity assay on CTC44 or CTC45 after overexpression of FTO. Mean ± S.E.M, **p-value < 0.01, *p-value < 0.05, Two-sided unpaired T-test. e FTO overexpression decreases ALDH activity in CTC cell lines. Flow cytometry quantification of ALDH positive cells after FTO overexpression. The number of ALDH positive cells in one representative biological replicate out of three for CTC44 and CTC45.