Effect Of Calcitriol Combinating DDP On Growth And Expression Of Skp2/p27in The Endometrial Carcinoma Transplantation Tumor Of Athymic Mouse

Objective:The purpose of the experiment is to observe the effect of calcitriol,DDP,calcitriol combinating DDP on human endometrial carcinoma (HEC-1-A)transplantation tumors of athymic mice, to analysis the expression of skp2and p27afterdrug treatment, to explore the drug’s mechanism in endometrial carcinoma.Thus, wewant to provide the theoretical basis and animal experiment basis for calcitriol that maytreat endometrial carcinoma as a kind of auxiliary cancer drug.Methods:1.The human endometrial carcinoma cell line (HEC-1-A) were cultured in vitro and wasinoculated subcutaneously into the oxter of nude mice to establish the xenograft model.The athymic mice were divided into four groups when the tumors grew to7-8mm.2.The mice were treated by intraperitoneal injection of drugs. The groups were asfollows:(1) Control group:0.25ml saline+0.1ml ethanol;(2) calcitriol group:0.05ugcalcitriol+0.25ml saline+0.1mlethanol;(3)DDP group:50ug DDP+0.25ml saline+0.1mlethanol;(4)combinating therapy group:0.05ug calcitriol+50ug DDP+0.25ml saline+0.1ml ethanol. The calcitriol, ethanol, saline were injected five times weekly, and theDDP was injected once a week.3.The basic situation of nude mice such as of diets, activities, reactions and mentalstates were observed daily. The weights of athymic mice were measured every four days.The length of the tumors was measured every5days. The volume of tumor wascalculated and the tumor growth curve was drawn. The weight and volume of the tumorwere measured and the tumor suppression rate was calculated after drug therapy.4.Histopathological changes were tested by hematoxylin-eosin staining (HE staining).5.The expression level of skp2/p27mRNA was examined by reversed transcript polymerase chain reaction (RT-PCR), and the expression level of skp2/p27protein wasdetected by western blotting.Result:1. The weight and volume of the tumor were measured after drug therapy. Comparedwith control group,the volume and weight of the tumors in calcitriol group,DDPgroup,combinating group decreased obviously(P<0.05), the volume and weight of thetumor in combinating group were less than calcitriol group and DDP group(P<0.05).The restraining tumor rates of three groups were44.89%(calcitriolgroup),52.39%(DDP group),69.90(combinating group).2.The change of body weight showed no difference between calcitriol group and controlgroup(P>0.05).The difference between the DDP/conbinating therapy group and controlgroup was siginficant(P<0.05) and difference between DDP group and conbinatingtherapy group was siginficant(P<0.05).3.HE staining showed that: Control group:tumor grew sheet, tumor cell density washigh, nuclear atypia was obvious and mitotic figures were active; calcitriol group andcisplatin group: the number of tumor cells reduced,cell density and mitotic activitydecreased significantly; combinating therapy group: tumor tissue showed a largenecrotic and only remnants of a small number of tumor cells as well as cell debris, witha small amount of inflammatory cells infiltration.4.Semi-quantitative RT-PCR and Western blot results showed:compared with controlgroup, Skp2mRNA and protein expression of calcitriol/DDP/conbinating therapygroup decreased significantly (P <0.05), Skp2mRNA and protein expression ofconbinating therapy group decreased significantly than the calcitriol and DDP group (P<0.05); Contrast to control group, mRNA level of p27was no significant change (P>0.05), but p27protein expression increased significantly (P <0.05), p27proteinexpression of conbinating therapy group was significantly higher than the calcitriol/DDP group (P <0.05).Conclusion: Calcitriol and DDP can inhibit the growth of endometrial carcinomatransplantation tumor of athymic mice,and the effect of calcitriol combined withcisplatin on the tumor inhibitory effect was significantly stronger than the single drug group. Calcitriol and DDP may inhibit the growth of tumor through down-regulation ofskp2gene and increase p27stability by decreasing the abundance of skp2.Therefoer,calcitriol and DDP is expected through synergies to reduce the amount of DDP toreduce the side effects of DDP and strengthen the anti-tumor effect at the same time.Calcitriol may treat endometrial carcinoma as a kind of auxiliary cancer drug.