Lappaol F Inhibits The Growth Of Colon Cancer Xenografts By Reregulating MDM2/14-3-3σ/YAP

ObjectiveTo evaluate the anticancer effect of Lappaol F(LAF),colon cancer xenograft model was established and treated with LAF.The regulation of LAF on Hippo-Yes-associated protein(YAP)signaling pathway,which plays an important role in cancer progression,was study to explore the anticaner mechanism of LAF.MethodsSW480 cells were injected subcutaneously into BALB/c female nude mice to establish a nude mice model of SW480 transplanted tumor and divided into four groups:solvent control group,LAF low-dose group(10 mg/kg),LAF high-dose group(20 mg/kg),and positive drug solvent control group(paclitaxel 10 mg/kg);The LAF treatment group was administered by tail vein injection for 15 consecutive days,and the paclitaxel group was administered every other day.Tumor weight and volume were measured to evaluate the inhibitory effect of LAF on tumor growth;TUNEL was used to detect the effect of LaF on apoptosis of tumor cells;Western blotting was used to detect the effect of LAF on the expression level of YAP,YAP target protein(Bcl-2,c-Myc,BIRC5)and YAP regulatory protein(14-3-3σ),and to further analyze the expression level of 14-3-3σ negative regulatory factor MDM2.The toxic effects of LAF on mice were evaluated by measuring the body weight,organ specific gravity and staining of liver and kidney pathological sections.ResultsLAF inhibited the growth of SW480 tumor.After LAF treatment,compared with solvent control group,tumor weight decreased by 37.9%(LAF low-dose group)and 37.8%(LAF high-dose group),tumor volume decreased by 37.7%(LAF low-dose group)and 41.4%(LAF high-dose group).TUNEL results showed that LAF could significantly promote the apoptosis of tumor cells.Western blotting results showed that the levels of YAP and its target proteins(BIRC5,c-Myc,Bcl-2)decreased significantly in tumor tissues of LAF low-dose group and LAF hight-dose group,the level of 14-3-3σ increased significantly,while the level of MDM2,the negative regulator of 14-3-3σ,decreased significantly.Although the levels of YAP and its target proteins(BIRC5,c-Myc,Bcl-2)in the tumor tissues of paclitaxel group also decreased significantly,the levels of 14-3-3σ and MDM2 did not change significantly,indicating that LAF and paclitaxel have different ways of regulating YAP.Compared to the solvent control group,the body weight of mice in LAF treatment group(low dose and high dose groups)had no significant change,but the paclitaxel-treated group showed significant weight loss.The visceral-body ratio results show there are no difference between the treatment groups and the solvent control group.The pathological results showed that stem cell congestion occurred in the LAF treatment group(low-dose and high-dose groups),and extramedullary hematopoiesis occurred occasionally in the LAF high-dose group.In renal tissue,vacuolar degeneration of renal tubular epithelial cells and a small amount of renal medullary capillary congestion appeared in high dose LAF group.In paclitaxel group,there were edema and degeneration of renal tubular epithelial cells,exfoliation of renal tubular epithelial cells and congestion of renal medullary capillaries.ConclusionLAF inhibits the growth of SW480 xenografts by inducing cancer cell apoptosis.The anticancer mechanism of LAF maybe involve downregulating the expression of MDM2,upregulating 14-3-3σ,and downregualting YAP and its downstream target proteins(BIRC5,c-Myc,Bcl-2)...