Fig. 2

PKMYT1 promotes DDP resistance in OS in vitro and in vivo. a The Efficiency of sgRNA Mediated PKMYT1 knockout in 143B, HOS, U2OS, and U2OS/DDP was determined by Western blot. b The IC50 of 143B, HOS, U2OS, and U2OS/DDP was calculated after the addition of gradient concentration of DDP for 24 h. P values were assessed by the one-way ANOVA. c, d The OS cells from A were subjected to treatment with DDP for 7–15 days (143B:0.2 μM, HOS and U2OS:0.4 μM, U2OS/DDP: 1 μM). Cell survival was determined by colony formation assay. e Quantification of clone formation number in PKMYT knockout cells treated with DDP. Error bars represent ± SD from three independent experiments. f–g Apoptosis analysis of PKMYT1 knockout cells treated with DDP for 24 h (143B:1 μM, HOS and U2OS:2 μM, U2OS/DDP: 10 μM). h Quantification of apoptosis rate of PKMYT knockout cells treated with DDP. Error bars represent ± SD from three independent experiments. i Schematic diagram of tumor xenograft experiments using PKMYT1 knockdown OS cells (143B). 5×10⁶ cells were subcutaneously injected into nude mice. Tumor volumes were measured at indicated days. j Representative images of tumors in each group after surgical resection. k Tumor volume measured on the indicated day is represented as mean ± SD. l Tumor weights were measured and represented as mean tumor weight ± SD. m–o PKMYT1 knockdown U2OS/DDP-Luc cells were orthotopically injected into mice. Starting on day 10, mice were treated with DDP (3.5 mg/kg) by i.p. injection once every 4 days for a total of three injections. m Representative images of living imaging of xenograft mouse model. n Representative immunohistochemical images Ki67 in the indicated xenografts tumors from (m). o Automated quantification of bioluminescence and Ki67 in the indicated xenografts tumors from (m). Data shown are mean ± SD Error bars, *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001