Effects of removal of abemaciclib, cisplatin, and pemetrexed on cell proliferation in MSTO-211H and H28 cells. (A,B) MSTO-211H cells were treated with abemaciclib (0.5 µM), cisplatin (0.3 µM), and pemetrexed (0.02 µM), or with the simultaneous combination of abemaciclib and chemotherapy for 6 days. (C,D) H28 cells were exposed to the above-described treatments, using abemaciclib 1 µM, cisplatin 1 µM, and pemetrexed 0.05 µM. After drug treatment, cells were cultured for additional 6 days in drug-free medium (recovery time). Cell proliferation was evaluated by crystal violet staining. Data are the medians of three separate experiments. Comparison among groups was made by using analysis of variance (one-way ANOVA), followed by Bonferroni’s post-test. *** p < 0.001, **** p < 0.0001 vs. control cells; § p < 0.05, §§§ p < 0.001, §§§§ p < 0.0001 vs. cisplatin + pemetrexed-treated cells; # p < 0.05, #### p < 0.0001 vs. abemaciclib-treated cells.