The Research Of Gene Methylation Impact In Lung Squamous Cell Carcinoma PRDM5Expression

【Objective】We aimed to explore the expression and the methylation status of PRDM5inlung squamous cancer samples and Paracancerous tissues samples,analysis of therelationship between the expression and DNA methylafion of PRDM5,and byxenograft experiments to investigate the potential feasibility of demethylationtherapy in the treatment of lung squamous cell carcinoma.【Methods】1. Collected30cases of of patients with lung squamous cell carcinoma of the lungtissue specimens, each patient specimens from lung cancer，Adjacent tissues(tumorsmaller than2cm distance) and distant lung tissue (greater than4cm from the tumor)specimens. Methylation specific PCR(MSP)was used to examine methylation levelsof PRDM5gene；RT-PCR and western blotting were performed to assess theexpression of prdm5mRNA and protein level,respectively.2. lung squamous cell carcinoma SK-MES-1cell lines in vitro were Cultured withdifferent concentrations of5-aza-2dC demethylation treament SK-MES-1.3.We had established the transplanted mode of human lung squamous cell carcinomain nude mice. Then we divided the23mice into2groups randomly:the treatmentgroup and the non-treatment group.During the experiment with a vernier calipermeasurement of the maximum longitudinal diameter and maximum diameter of thetumor.In treatment group we injected the demethylation agent5-aza-2dc drug（1ug/g）in nude mice abdominal cavity.in every week3times, the non-treatmentgroup treated with normal PBS,the method of injection is same as treatment group.We could observe the nude mice’s growth condition and then we killed nude after28days.Take the intact subcutaneous tumor tissues，and then measure their volumes andtheir weight．Tumor growth inhibitory rate was calculated finally．We can measure tumor volume and draw tumor growth curve Figure. The PRDM5gene expressionand its methylation status in the tumors were detected using methylation specificPCR(MSP),RT-PCR,Western blotting.【Results】1.High frequent promoter methylation was found for PRDM5gene in lungsquamous carcinoma(73.3％)，adjacent lung tissue(46.7%）and Distant tissue(16.7％)(P<0.05）. The methylation might be reasons for decreased or lossed expressionsof PRDM5.2.PRDM5showed low expression in lung squamous cell carcinoma and adjacenttissues,followed by the table in the distant lung tissue with the highest expressiondifference between the group was statistically significant (P<0.05).PRDM5methylation was significantly correlated with the differentiation degree and Lymphnode metastasis (P<0.05), but not associated with age、gender、smoking and clinicalstaging(P＞0.05).3.After treatment with5-aza-2dc,the inhibition rate of the growth of culturedsk-mes-1cells was enhanced with increased drug concerntration.4.In the treatment group,the subcutaneous tumors grew slowly and after treatment，the mean volume(570.63±196.97)mm3and mean weight(0.785±0.368)g weresignificantly． Whereas corresponding to the non-treatment group were(1499.09±350.45）mm3,tumor weight(2.045±0.605)g(P<0．05)， The tumor growthinhibitory Rate as57.79％in treatment group．MSP showed that methylation ofPRDM5gene in the non-treatment group (72.3%)and in the treatment group（27.3%）.The expression levels of PRDM5mRNA and protein in tumor tissues ofthe non-treatment group were obviously lower compared with treatment group(P<0．05)．Demethylation drugs(5-aza-2dc) were able to PRDM5gene methylationstatus and raised the level of gene expression.【Conclusions】1.The expression of PRDM5was down regulation in lung squamous cell carcinoma，There was significant correlation between the low expression of PRDM5，and the aberrant methylation of PRDM5gene.2.This study shows that the demethylation agent (5-aza-2dc) inhibit the growth ofhuman lung squamous cell carcinoma SK-MES-1cells in culture and in nudemice,Its mechanism may be that demethylation of the methylatedPRDM5.Demethylation therapy in the treatment of lung squamous cell carcinoma ofpotential viability.