O-acetyl RT sensitizes H292 to cisplatin. (A) Cell viability of NSCLC H292 cells treated with 0.01 and 0.05 µM of O-acetyl RT for 24 h prior to treatment with 50 µM of cisplatin was determined using the MTT assay. (B) Effect of O-acetyl RT sensitization on cell growth of H292 cells was observed using a colony formation assay. (C) Hoechst 33342/PI double staining was used to determine cell apoptosis. (D) The expression levels of apoptosis-associated proteins in H292 cells treated with 0.05 µM of O-acetyl RT for 24 h prior to treatment with 50 µM of cisplatin were assessed by Western blotting, and (E) the relative expression was calculated using densitometry. (F) The expression levels of activated ERK (p-ERK), total ERK, and p53 were also examined using Western blotting, and (G) the relative expression was calculated using densitometry. Data represent the mean ± SD (n = 3). Bars labeled with different letters (a, b, c, d) are significantly different at p < 0.05.