Abstract: To investigate the effects of rhein lysinate (RHL),taxol and their combination on the proliferation and apoptosis of lung cancer H460 cells,and to clarify their mechanisms. Methods The lung cancer H460 cells in logarithm growth phase were selected and randomly divided into   control group(adding no drug),taxol group(1 μmol•L^-1 taxol),RHL group(100 μmol•L^-1 RHL)  and taxol combined with RHL group;at the same time,blank control group was set up. MTT assay was used to detect the proliferation of H460 cells and flow cytometry method was used to analyze the apoptotic rates in various groups 48 h after treatment. The expression levels of apoptosis-related  proteins  and MEK/ERK proteins were detected  by Western blotting method. Results
After culture for 48 h,the cell proliferation rate in taxol combined with RHL group was lower than those in control,taxol,and RHL groups (P<0.05); the apoptotic rate in taxol combined with RHL  group was higher than those in control,taxol,and RHL groups (P<0.05);the expressions of  caspase-3 and poly ADP-ribose polymerase (PARP) fragment protein  in  taxol combined with RHL  group were higher than those in control,taxol,and RHL groups;whereas the expressions of Bcl-2 and NF-κB proteins were lower than those in control,taxol,and RHL groups. Moreover,the phosphorylation levels of MEK and ERK proteins up-regulated  by taxol in RHL group were decreased.  Conclusion Both taxol and RHL can inhibit cell proliferation and induce apoptosis of lung cancer H460 cells,and RHL can enhance the taxol-induced cytotoxicity and apoptosis by reducing the activity  of ERK and increasing the expression levels of  caspase-3 and PARP fragment protein.

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