The Clinical Study And Mechanism Of Jianpi Yangwei Decoction On Intervention Of 5-fu Drug Resistance In Gastric Cancer Mediated By DNA Damage Repair Enzyme FEN1

Objective:The clinical and experimental studies are conducted to explore the effect of Jianpi Yangwei Decoction(JPYW)on improving the chemotherapy efficacy of advanced gastric cancer and the preliminary mechanism of inhibiting 5-Fu drug resistance in gastric cancer based on regulating the expression of DNA damage repair enzyme FEN1.Methods:1.Fifty patients with advanced gastric cancer in the Department of Oncology,Jiangsu Province Hospital of Chinese Medicine are enrolled and divided into two groups,each with 25 patients.The experimental group is treated with JPYW along with chemotherapy,while the control group is treated with chemotherapy only.Tumor size,peripheral blood FEN1 expression,life quality score,TCM symptom score,safety indexes are recorded before and after treatment.SPSS26.0 software is used for data analysis to compare the therapeutic effect difference between the two groups.2.The relationship between FEN1 and gastric cancer resistance to 5-Fu and the effect of JPYW on BGC823/5-Fu drug resistance and its intervention effect on FEN1 mediated DNA damage repair:①The difference in DNA damage repair efficiency between non-resistant cells BGC823 and drug-resistant cells BGC823/5-Fu is compared by HT8-oxo-dG ELISA Kit using the method of 8-oxo-dG determination in vitro.②Q-PCR and Western blot are used to compare the mRNA and protein expression differences of DNA damage repair related genes APE1,FEN1,Pol β and XRCC1 in BGC823 and BGC823/5-Fu.③Flow cytometry is used to detect the effect of JPYW combined with 5-Fu on the apoptosis rate of BGC823/5-Fu at various concentrations using Annexin V-FITC/PI Apoptosis Kit.④Immunofluorescence experiment is conducted to observe the effect of JPYW combined with 5-Fu on the phosphorylation level of γ-H2AX in BGC823/5-Fu at various concentrations,which directly reflect its damage to cellular DNA.⑤The same method of the 8-oxo-dG determination in vitro is used to detect the effect of JPYW on DNA damage repair efficiency in BGC823/5-Fu at various concentrations.⑥Q-PCR and Western blot are used to determine the effect of JPYW on the expression of FEN1 mRNA and protein in BGC823/5-Fu at various concentrations.Results:1.Clinical research results:①Objective tumor curative effect:The objective response rate(ORR)in the experimental group is higher than the control group(40%vs 28%),but there is no statistical difference(P>0.05).②Peripheral blood FEN1 expression:Before and after treatment,the FEN1 gene expression in the experimental group remains stable(P>0.05),and the FEN1 expression in the control group increases significantly(P<0.01);After treatment,the control group’s FEN1 expression is notably higher than the experimental group(P<0.05).③Life quality score:Before and after treatment,the experimental group improved in terms of the total health status,physical and role function and symptom scores,while the control group only improved in role function and pain symptom(P<0.05).After treatment,fatigue,nausea and vomiting symptom and general health status in the experimental group are significantly improved compared with the control group(P<0.05).④TCM symptom score:The TCM symptom recovery rate in the experimental group is obviously higher than that in the control group(64%vs 28%,P<0.05).Before and after treatment,the symptoms of belching,stomach distention,poor appetite,vomiting,fatigue and the overall score in the experimental group are significantly improved(P<0.05),while the control group has no variation.After treatment,the experimental group is better than the control group in stomach distension,poor appetite,vomiting,fatigue and total score(P<0.05).⑤Safety evaluation:There is no obvious difference in the occurrence of myelosuppression and liver and renal abnormal function between the two groups(P>0.05).2.Experimental research results:①The repair efficiency of BGC823/5-Fu is significantly higher than that of BGC823(73.52±2.93%vs 40.97±2.19%,P<0.01).The expression levels of FEN1 gene and protein in BGC823/5-Fu are higher than those in BGC823(P<0.01).②Medium and high concentrations of JPYW combined with 5-Fu can increase the apoptosis rate of BGC823/5-Fu(P<0.01);JPYW combined with 5-Fu can directly cause DNA damage in BGC823/5-Fu,and the phosphorylation level of γ-H2AX increases with the increasing concentration of JPYW;All concentrations of JPYW can significantly reduce the DNA damage repair efficiency of BGC823/5-Fu(P<0.01);JPYW can significantly reduce the FEN1 gene and protein expression level in BGC823/5-Fu with the concentration increased.Conclusions:1.JPYW can maintain the stability of FEN1 gene in the body during chemotherapy,resist excessive DNA damage repair of tumor cells after chemotherapy,thereby improving the chemotherapy efficiency.This prescription can also improve the life quality and the TCM symptoms of patients with gastric cancer.And the clinical use safety is good.2.The high expression of FEN1 is an important feature of BGC823/5-Fu,which directly leads to the increase in the efficiency of DNA damage repair,and to a certain extent leads to the resistance of gastric cancer cells to 5-Fu.3.JPYW can cause DNA damage in drug-resistant cells through reducing the level of DNA damage repair mediated by FEN 1,and increase the apoptosis rate of drug-resistant cells thus to reduce the resistance of gastric cancer to 5-Fu.