| Background: Pancreatic adenocarcinoma is one of the most deadly malignancies,characterized by rapid spread and a dismal prognosis.The early stages of PAAD lack obvious clinical symptoms,which delays treatment.It is estimated that only 20% of patients diagnosed with PAAD can undergo surgery,and the 5-year survival rate after surgery increases by only 20%-30%.Considering the high mortality rate and the limited treatment effect of PAAD patients,it is imperative to develop a prognostic model and then develop a treatment plan based on it.Recent studies have indicated that pyroptosis may participate in the regulation of tumorigenesis and immune microenvironment.However,the role of pyroptosis-related genes(PRGs)in PAAD remains to be fully defined.Method: The RNA-sequencing data and corresponding clinical information of 486 patients with PAAD were obtain from The Cancer Genome Atlas(TCGA).We constructed a prognostic gene model based on PRGs by LASSO Cox regression.The correlation between PRGs and prognosis,immune infiltration,immune checkpoints,and tumor mutational burden(TMB)was analyzed by Kaplan-Meier curve,univariate Cox,multivariate regression,and Spearman’s analysis in PAAD patients.Biological functions of PRGs were determined by gene ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment analysis.Prediction of mi RNA-m RNA and mi RNA-lnc RNA pairs by Tar Base V.8 database and mi RNet database,and star Base and GEPIA database were used to analyze the expression and prognosis of mi RNAs and lnc RNAs in pancreatic cancer to construct a competitive endogenous RNA(ce RNA)network.The PAAD cell line PANC-1 with low knockdown of CASP6 was constructed,and q RT-PCR and Western blot techniques were applied to detect the knockdown efficiency of CASP6 in PANC-1 cells,and CCK-8 assay,Wound healing and Transwell assay were used to detect the proliferation,migration and invasion of CASP6 in PANC-1 cells.Results: Our results showed that 31 PRGs were up-regulated in PAAD.Prognostic analysis screened 10 genes with clinical prognostic value(AIM2,CASP3,CASP4,CASP5,CASP6,CASP8,GSDMC,IL18,NLRP2 and PYCARD).The PRGs were mainly involved in pyroptosis,NOD-like receptor signaling pathway,and response to bacteria.Then,we established a novel 4-gene(CASP4,GSDMC,IL18 and NLRP2)signature related to PRGs for evaluating the prognosis of PAAD patients.Patients with PAAD in the low-risk group had a better prognosis than those in the high-risk group.The nomogram suggested that the 1-,3-,and 5-years survival probability exhibited robust predictive performance.Significant correlation was observed between prognostic PRGs and immune infiltration,immune checkpoints,and tumor mutational burden.Moreover,we first identified the potential competing endogenous RNA regulatory axis in PAAD: lnc RNA PVT1/hsa-mi R-16-5p/CASP6/CASP8.Besides,CASP6 knockdown cell lines were established and CCK-8 assay showed that the proliferation rate of PANC-1 cells was decreased after CASP6 knockdown compared to the control group.The Wound healing assay showed that the migratory ability of PANC-1 cells was decreased after CASP6 knockdown compared to the control group.Transwell assay showed that the invasive ability of PANC-1 cells was reduced after CASP6 knockdown compared to the control group.Conclusion: CASP6 could be a potential biomarker,promoting the occurrence and progression in PAAD.The lnc RNA PVT1/hsa-mi R-16-5p/CASP6/CASP8 regulatory axis plays an vital role in regulating the anti-tumor immune responses for PAAD. |
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