MicroRNA-155 Mediated TGF-β1/SMAD2-CyclinD1 Pathway Negative Regulation Of Gastric Cancer And Intervention Of The Qingre Huashi Decoction

Objective: It is planned to establish a tumor-bearing mouse model of gastric cancer with overexpression of mi RNA-155 from the animal experiment level.Under the guidance of traditional Chinese medicine theory,modern molecular biological technologies such as Western-blot and Quantitative real-time PCR are applied to study the negative regulation of TGF-β1/SMAD2-Cyclin D1 pathway mediated by mi RNA-155 to the changes of related indicators in gastric cancer and the possible mechanism of the intervention of Qingre Huashi Decoction.Methods: According to the optimal MOI value of lentivirus screening,mi RNA-155 overexpressed AGS cells were constructed by lentivirus transfection.The 36 SPF nude mice were randomly divided into 6 groups on average.The mi RNA-155 overexpressed group was subcutaneously injected with AGS cells in the right axilla,while the other groups were subcutaneously injected with AGS cells.From the second day of modeling,groups were given intragastric administration: the overexpression group and the model group were not given medication and grew naturally;The TCM treatment group was given 5%,10% and 20% Qingre Huashi Decoction by intragastric gavage.The control group received intraperitoneal injection of chemotherapy drugs.After 3 weeks of continuous intervention,the nude mice were killed,the tumor size and volume were observed,and the tumor inhibition rate was calculated by taking photos.Subsequent pathological sections of tumor specimens were performed to understand the morphology and structure of tumor tissue cells.The protein expression levels of SMAD2 and Cyclin D1 were detected by Western-blot,and the m RNA expression levels of mi RNA-155,SMAD2 and Cyclin D1 were detected by Quantitative real-time PCR.Results: 1.Compared with AGS model group,the Qingre Huashi Decoction treatment group,chemotherapy control group and mi RNA-155 overexpression group all inhibited tumor growth.The mi RNA-155 overexpression group had the highest tumor inhibition rate,and the tumor inhibition rate in the Qingre Huashi Decoction treatment group was dosedependent.2.HE staining section showed that the tumor tissues of the model group showed compact cell arrangement,large nucleus and darker staining under light microscope.The mi RNA-155 express group,chemotherapy group and Qingre Huashi Decoction groups after treatment tumor cells than model group appeared different degree arrangement loose,lighter nuclei and focal necrosis,of which the mi RNA-155 express group of focal necrosis is most obvious,the control group,Qingre Huashi Decoction treatment between groups of focal necrosis is obviously dose dependent.3.RT-PCR results showed that compared with the model group,mi RNA-155 expression level was increased in the overexpression group,the control group and the Qingre Huashi Decoction treatment group,and the degree of mi RNA-155 expression in the Qingre Huashi Decoction treatment groups was significantly dosedependent.Compared with model group,mi RNA-155 overexpression group,control group,high and medium dose Qingre Huashi Decoction treatment group had statistical significance(P < 0.05),but there was no statistical significance between low dose Qingre Huashi Decoction group and model group(P > 0.05).The m RNA expression levels of SMAD2 and Cyclin D1 were opposite to those of mi RNA-155.Compared with the model group,the m RNA expression levels of SMAD2 and Cyclin D1 were decreased in the mi RNA-155 overexpression group,the control group and the Qingre Huashi Decoction treatment groups,and the decrease degree of m RNA in the Qingre Huashi Decoction treatment groups was significantly dose-dependent.Compared with model group,mi RNA-155 overexpression group,control group,high and medium dose Qingre Huashi Decoction treatment group had statistical significance(P < 0.05),but there was no statistical significance between low dose Qingre Huashi Decoction group and model group(P >0.05).4.Western Blot results showed that compared with model group,mi RNA-155 overexpression group,chemotherapy control group and Qingre Huashi Decoction treatment group all reduced the protein expression levels of SMAD2 and Cyclin D1 in tumor tissues.Compared with model group,the expression of SMAD2 and Cyclin D1 protein in mi RNA-155 overexpression group,chemotherapy control group and treatment high-dose group were statistically significant(P < 0.05),there was no statistical significance in Qingre Huashi Decoction treatment medium and low dose groups(P > 0.05).Conclusion: Mi RNA-155 can negatively regulate gastric cancer by mediating the TGF-β1/ SMAD2-Cyclin D1 pathway and inhibit the progression of gastric cancer.By promoting the expression of mi RNA-155,the Qingre Huashi Decoction can mediate the TGF-β1/ SMAD2-Cyclin D1 pathway,reduce the expressions of SMAD2 and Cyclin D1,and achieve the effect of inhibiting the progression of gastric cancer.