TP53 and cancer: To confirm that the suppression of autophagy in fibroblasts was induced by the inactivation of p53 in cancer cells, we used HT29 cells that are colon cancer cells with mutations in TP53. Autophagy in CCD-18Co cells was significantly suppressed even when co-cultured with HT29 cells than that in CCD-18Co cells cultured alone, similar to the condition in CCD-18Co cells co-cultured with HCT116sh p53 cells (Fig. 1e).