Abstract: Objective To evaluate the inhibitory effect of gitoxin on non small cell lung cancer with drug-resistance in vitro and in vivo and explore the underlying molecular mechanism Methods Survival and apoptosis rates of H1975 were measured by MTS assay and flow cytometry respectively after gitoxin and gefitinib treatments. Tumor volumes of gitoxin treated xenograft nude mice were calculated by measuring the lengths and widths of these tumors. The phosphorylation of Erk1/2 was analyzed by Western blot. Results Gitoxin can inhibit the growth of H1975 and induce its apoptosis more effectively than gefitinib. It can also inhibit growth of transplanted tumors in nude mice. In addition, gitoxin can inhibit the phosphorylation of Erk1/2 in a dosage and time-point dependent way. Conclusion Gitoxin may offer a potential treatment for drug resistant NSCLC.

Key words: gitoxin, H1975, xenograft nude mouse model, Erk1/2 signal pathway