Abstract: Objective To investigate the effect of Rhein lysinate (RHL), cisplatin and their combination on the proliferation, apoptosis of lung cancer A549 cells, and to provide theoretical foundation for cisplatin combined with RHL against human lung cancer. Methods The lung cancer A549 cells in logarithm growth phase were selected as the research object, and were randomly divided into four groups: blank control group, cisplatin group, RHL group and combination groups. MTT assay was used to detect A549 cell proliferation and flow cytometry was used to analyze cell apoptosis in various groups after 48 h. The expression levels of protein associated with apoptosis and protein of ERK were detected after 48 h by Western blotting. Results Cell proliferation was inhibited and cell apoptosis was induced in groups of cisplatin and RHL, but there was a significant reduction in proliferation and a significant increase in apoptosis in A549 cells treated with a combination of cisplatin and RHL compared with cisplatin or RHL treatment alone (P<0.05, respectively). The expressions of cleaved caspase-3, caspase-7 and poly ADP-ribose polymerase (PARP) in combination groups were higher than those of either agent alone group after 48 h cell culture in A549 cells, whereas the expression of BCL-2 was lower than those of either agent alone group and the expressions of BAX was higher than those of either agent alone group. Moreover, RHL could downregulate the phosphorylation of ERK induced by cisplatin. Conclusion RHL potentiates the cisplatin-induced cytotoxicity and apoptosis by reducing the activation of ERK and increasing the levels of cleaved caspase-3, caspase-3 and PARP.

Key words: rhein lysinate, Cisplatin, lung cancer, apoptosis, combination therapy