Fig. 1: CRC PDOs do not display ALT markers.

A C-circles assays (CCA, n = 3) were performed on 40 ng of genomic DNA extracted from ALT cells (HeLa) and on DNA (from 80 ng to 5 ng) extracted from ALT+ cells (U2OS). Representative dot blot is shown. Mean with SEM and individual values are shown. One-way ANOVA, Dunett’s multiple comparison test: each column compared with HeLa (***P < 0,001; **P < 0,002; *P < 0,033; ns=not significant). B 91 CRC PDOs were tested for C-circles (CCA, n = 91). Quantification was normalized on ALT+ cell line (U2OS, n = 4). Mean with SEM and individual values are shown. One-way ANOVA, Dunett’s multiple comparison test: each column compared with HeLa (n = 3), (***P < 0,001; ns = not significant). C CCA was carried out in triplicate (n = 3) on 7 (3 ATRXwt and 4 ATRXmut) selected PDOs. Quantification of the levels of C-circles is shown. Kruskall–Wallis test, Dunett’s multiple comparison test: each column compared with HeLa (**P < 0.002). D Representative dot blot for CCA on PDOs. Negative (HeLa) and positive (U2OS) controls are shown in (A). E Selected PDOs were studied for APBs and telomere intensity (n = 3). Representative images show cell nuclei (DAPI), telomeres and PML. F Number of APBs in cells from selected PDOs. Mean with SEM and individual values are shown. Kruskall–Wallis test, Dunett’s multiple comparison test: each column compared with HeLa. G Telomere intensity in selected PDOs as measured by FISH (n = 3). Each point represents a telomere. U2OS and HeLa cell lines were used as ALT+ and ALT- controls in all experiments, respectively.