Abstract: Objective The Objective of this study was to investigate the effect of polyene phosphatidylcholine(PPC)on the reversal of resistance to human oxaliplatin-resistant cell lines(SGC-7901/L-OHP)in nude mice and its mechanism.Methods The subcutaneous xenograft model of nude mouse was established with a secondary drug-resistant SGC-7901/L-OHP cell line and randomly divided into four groups:blank control group,oxaliplatin group,PPC group and oxaliplatin combined with PPC group.The mice were administered continuously for 14 days.After 21 days,the nude mice were sacrificed and the tumor tissues were removed.The tumor volume and inhibitory rate of tumor were recorded.The RNA and protein of tumor tissue were extracted from the resected tumor tissue.Real-time quantitative PCR(qRT-PCR)and western blot were used to examine the expression of TLR4,Nanog and ABCF2.Results After treatment,the proliferation of transplanted tumor cells in L-OHP group and L-OHP+PPC group was inhibited compared with the blank control group,P value was <0.001,the two drugs combined interaction,P=0.008;The volume inhibition rate of the L-OHP+PPC group was higher than that of the blank control group(P＜0.001)and the L-OHP group(P＜0.001).The mRNA expression of TLR4/Nanog/ABCF2 in L-OHP+PPC group was significantly different from that in the control group(TLR4:P＜0.001;Nanog:P＜0.001;ABCF2:P＜0.001);The mRNA expression of TLR4/Nanog/ABCF2 in L-OHP+PPC group was significantly different from that of L-OHP group(TLR4:P＜0.001;Nanog:P＜0.001;ABCF2:P＜0.001).The combination of the two drugs had an interaction effect on the mRNA expression of TLR4/Nanog/ABCF2(TLR4:P＜0.001;Nanog:P＜0.001;ABCF2:P＜0.001).The protein expression of TLR4/Nanog/ABCF2 in L-OHP+PPC group was significantly different from that in the control group(TLR4:P=0.006;Nanog:P=0.017;ABCF2:P=0.014);The protein expression of TLR4/Nanog/ABCF2 in L-OHP+PPC group was significantly different from that of L-OHP group(TLR4:P＜0.001;Nanog:P＜0.001;ABCF2:P＜0.001).The combination of the two drugs had an interaction effect on the protein expression of TLR4/Nanog/ABCF2,and the difference was statistically significant(TLR4:P=0.014;Nanog:P=0.01;ABCF2:P=0.015).Conclusion PPC has a reversal resistance to human gastric cancer-resistant oxaliplatin(SGC-7901/L-OHP)cell line in nude mouse,possibly by reducing TLR4,Nanog,ABCF2 at the levels of mRNA and proteins to reverses the drug resistance of human gastric cancer resistant cells.

Key words: Polyene phosphatidylcholine, Oxaliplatin, Gastric cancer, Nude mouse model