Fig. 2

Lactate-derived lactylation induces HR and promotes EPI resistance. a Pan-Kla and β-actin levels were determined by western blot in E-resistant UM-UC-3 cells before or 24 h after treatment with 0.2 μM EPI, 20 mM sodium lactate, and/or 20 mM sodium oxamate as indicated. b Viability of E-resistant UM-UC-3 cells before or 24 h after treatment with 0.2 μM EPI, 20 mM sodium lactate, and/or 20 mM sodium oxamate; one-way ANOVA followed by Tukey’s test. c Representative images of comet assays performed with E-resistant UM-UC-3 cells treated with the same experimental setup as described in b; the percentage of DNA tails was compared by one-way ANOVA followed by Tukey’s test; scale bar: 100 μm. d AsiSI-ER U2OS system and qPCR-based quantification of single-stranded DNA (ssDNA) generated by DNA end resection; ssDNA levels were normalized to those of the control (-4OHT) group; one-way ANOVA followed by Tukey’s test. e The same experimental setup as in b, followed by western blot analysis of RAD51 accumulation in chromatin fractions and γH2AX expression in whole-cell extracts. f Same experimental setup as in b. Representative images (left) and quantitative analyses (right) showing the formation of EPI-induced γH2AX (green) foci merged with DAPI (blue); scale bar: 10 μm. g Nude mice were transplanted subcutaneously with E-resistant UM-UC-3 cells and treated with EPI (2 mg/kg), sodium lactate (100 mg/kg), or sodium oxamate (500 mg/kg); representative tumor images are shown (n = 5). h Western blot analysis of pan-Kla and γH2AX (whole-cell extracts) and RAD51 (chromatin fractions) from CDX models. Except for panels g and h, the graphs represent three replicates per condition (n = 3). ***p < 0.001, **p < 0.01, *p < 0.05 represent significant differences between two groups; ns represents no significant difference