The Effect And Mechanism Of MiRNA Let-7a On The Growth Of Laryngeal Carcinoma Xenografts In Nude Mice By Regulation Of HMGA2

Objective:To study the effect and mechanism of miRNA let-7a on the growth of laryngeal carcinoma xenografts in nude mice by regulation of high-mobility group A2,which provides new ideas for the study of pathogenesis of laryngeal carcinoma and provides.Method:The chemically synthesized human let-7a mimics and let-7a mimics negative control were transfected into human laryngeal carcinoma Hep2 cells by cationic liposome.The Hep-2cells were divided into 3 groups:blank group(Hep-2 cells),let7 group(transfected let-7a mimics),NC group(transfected let-7a/NC).The hep2 cells of let-7a mimics group,let-7a NC group and Hep2 cells alone were injected subcutaneously in nude mice.After 30 days,nude mice were sacrificed to measure the transplanted tumor volume and weighed.Then tumor sections were subjected to HE staining;The expression of microRNAs let7a and HMGA2 mRNA were detected by qRT-PCR;.The expression of HMGA2protein was detected by immunohistochemistry and Western blot.Result:(1)All nude mice were exposed to visible tumors after 5?6 days of implantation and the tumor formation rate was 100%.We began to touch the small round mass on the right side of the back of the neck of the mouse,which gradually grew irregularly.HE staining showed that the nuclei of transplanted tumor were increased,the nucleolus was deeply stained and the cell atypia was obvious,which was consistent with the characteristics of human laryngeal carcinoma Hep-2 cell transplantation tumor.These results suggest that we successfully constructed an animal model of Hep-2 cell line.(2)The final transplanted tumor volume of the Let7a group,NC group and blank group were(232.201±28.342)mm~3?(507.808±51.48)mm~3?(529.657±44.43)mm~3,respectively.The final tumor volume of the three groups was not exactly the same,with significant differences(F=75.961,P=0.000).There was no significant difference between the NC group and the blank group(q=21.849,P=0.432),and there was significant difference between the other groups(P<0.01).The quality of the final transplanted tumor in the Let7a mimics group,let7NC group and blank group were(0.863±0.110)g?(0.813±0.106)g and(0.194±0.040)g,respectively.The quality of the three groups was not exactly the same(F=99.887,P=0.000);There was no significant difference between the blank group and the NC group(q=0.498,P=0.360),There were significant differences between the other groups(P<0.01).(3)By qRT-PCR,we detected detection that the expression of miRNAs let7a in let7a mimics group was significantly up-regulated,and the expression of HMGA2 mRNA was significantly lower than that in Hep-2/NC group and Hep2group,which were significant differences(P<0.05).By immunohistochemistry,we found that the positive expression rate of HMGA2 protein in the blank group and let7 NC group was significantly higher than that in the let7 group,the difference was statistically significant(P<0.05).By Western blot method,we found that the average gray value of HMGA2protein in the blank group and let7 NC group was significantly higher than that in the let7 group,the difference was statistically significant(P<0.05).Conclusion:We successfully constructed a human laryngeal carcinoma Hep2 cell xenograft model in nude mice and further confirmed that let-7a can down regulate the expression of HMGA2protein and inhibit the growth of laryngeal carcinoma cells in nude mice,which provides a new theoretical basis for the molecular mechanism of the proliferation and metastasis of laryngeal carcinoma and the target of drug targeted therapy for laryngeal cancer.