Integrin α6 deletion induces the deadhesion and apoptosis of murine BCR-ABL1⁺ (p210) ALL cells. (A) Immunophenotype of murine BCR-ABL1 (p210)⁺ ALL cells. (B) Deletion of α6 induced by tamoxifen (1.5 μM) was confirmed by flow cytometry 6 days after tamoxifen treatment. Left panel: cells not plated on mlaminin-1; right panel: cells plated on mlaminin+. (C) Deletion of α6 was confirmed by genomic PCR. Hypoxanthine-guanine phosphoribosyltransferase (HPRT) was used as a PCR DNA and loading control. (D) Cell cycle analysis of CreER^T2 and EmptyER^T2 cells on day 5 after deletion by bromodeoxyuridine flow cytometry. ***P < .001 and ****P < .0001 by 1-way ANOVA with post hoc analysis (Tukey test). (E) Percentage of adherent CreER^T2 and EmptyER^T2 cells on mlaminin-coated plates on day 5. ***P < .001 by Student t test. (F) Apoptosis analysis by annexin V and 7-AAD staining of CreER^T2 and EmptyER^T2 cells at day 5 after deletion. ***P < .001 by Student t test. (G) Western blot of cleaved caspases 3, 7, 8, and 9 in CreER^T2 and EmptyER^T2 cell lysates on day 5 after deletion. β-actin, loading control. (H) Percentage of α6 and (I) annexin V expression in CreER^T2 and EmptyER^T2 cells at various time points after α6 deletion, as determined by flow cytometry. Mean ± standard deviation is shown. *P < .05 and ***P < .001 by 1-way ANOVA with post hoc analysis (Tukey test). (J) Western blot of cleaved poly (ADP-ribose) polymerase (PARP) and p53 in CreER^T2 and EmptyER^T2 cells on various days (days 0, 4, 5, and 6) after tamoxifen-induced α6 deletion. β-actin, loading control. One of 3 experiments is shown.