牙龈卟啉单胞菌感染及PDCD4低表达对食管癌细胞紫杉醇化疗的影响

Effects of Porphyromonas gingivalis infection and low expression of PDCD4 on paclitaxel chemotherapy in esophageal cancer cells

目的:分析牙龈卟啉单胞菌(Pg)感染及程序性细胞死亡因子4(PDCD4)低表达对食管癌细胞KYSE30紫杉醇(PTX)化疗的影响。方法:制备PDCD4敲降的食管癌细胞KYSE30-P。实验分为4组,KYSE30组、KYSE30-P组、KYSE30+Pg组、KYSE30-P+Pg组。采用Western blot法及流式细胞术检测细胞中PDCD4、干细胞标记物乙醛脱氢酶1(ALDH1)蛋白表达量及肿瘤干细胞(CSC)百分比,采用CCK-8法检测PTX处理细胞24 h的IC_(50)。24只裸鼠均分为4组,按以上分组接种细胞,成瘤后每3 d尾静脉注射一次PTX(10 mg/kg),共给药6次。末次给药后第3天观察成瘤能力,检测瘤体组织中PDCD4、ALDH1表达量及CSC百分比。结果:Pg感染与PDCD4敲降均可降低KYSE30细胞中PDCD4蛋白表达量,增高ALDH1蛋白表达量、CSC百分比及PTX处理24 h的IC_(50),二者存在协同作用(P均<0.05)。Pg感染与PDCD4敲降均可引起裸鼠瘤体对PTX敏感性减弱,瘤体增重,瘤体内PDCD4蛋白表达量降低,而ALDH1蛋白表达量及CSC百分比增高,二者存在协同作用(P均<0.05)。结论:有效清除Pg并激活PDCD4可能为食管癌治疗的新策略。

Aim:To analyze the effects of Porphyromonas gingivalis(Pg)infection and low expression of PDCD4 on paclitaxel(PTX)chemotherapy in esophageal cancer cells.Methods:The PDCD4 knockdown cell line KYSE30-P was prepared.The experiment included 4 groups,KYSE30 group,KYSE30-P group,KYSE30+Pg group and KYSE30-P+Pg group.The expressions of PDCD4,ALDH1 proteins and percentage of cancer stem cells(CSC)in each group were detected by Western blot and flow cytometry,respectively.The IC_(50) of PTX(24 hour)was detected by CCK-8 assay.A total of 24 nude mice were allocated into 4 groups,and the cells were inoculated according to the above groups.PTX(10 mg/kg)was injected via tail vein every 3 days after tumor formation for 6 times in total.The tumor-forming ability of nude mice in each group was compared 3 days after the last administration,and the expressions of PDCD4,ALDH1 proteins and percentage of CSC in tumor tissue of nude mice in each group were detected.Results:Both Pg infection and PDCD4 knockdown could decrease the expression of PDCD4 protein in KYSE30 cells,increased the expression of ALDH1 protein,percentage of CSC,and IC_(50) of PTX,indicating a synergistic effect between the 2 factors(P<0.05).Both Pg infection and PDCD4 knockdown induced decreased sensitivity to PTX in nude mice,enhanced tumor-forming ability,decreased PDCD4 protein expression,and increased ALDH1 protein expression and percentage of CSC,indicating a synergistic effect(P<0.05).Conclusion:Effective clearance of Pg and activation of PDCD4 may provide a new strategy for the treatment of esophageal squamous cell carcinoma.