Analysis Of The Prognostic Significance And Potential Mechanisms Of LncRNAs Associated With M6A Methylation In Papillary Thyroid Carcinoma

Objective: long non-coding RNAs(lnc RNAs)associated with N-6-methyladenosine(N6-methyladenosine)play an important role in the progression of multiple tumors and can be used as prognostic markers.However,whether m6A-associated lnc RNAs also play the same role as prognostic markers in Papillary thyroid carcinoma(PTC)remains unclear.The purpose of this study is to establish and verify the prognosis model of PTC based on M6A-related lnc RNAs,so as to screen PTC patients with poor prognosis and apply it to precision medicine.Methods: Transcriptome data of PTC tumor tissue and normal tissue were obtained from The Cancer Genome Atlas(TCGA),23 m6A-related genes were obtained from literature,and m6A-related lnc RNAs were screened by Pearson correlation.Subsequently,bioinformatics methods were used to screen out lnc RNAs with differential expression and prognostic correlation.TCGA-THCA cohort was divided into two subtypes by consensus cluster analysis based on the expression levels of differentially expressed and prognostic related lnc RNAs.Least absolute shrinkage and selection operator(LASSO)regression analyses were then performed to create and validate prognostic models.The relationship between risk score,clustering,programmed death-ligand 1(PD-L1),tumor microenvironment(TME),clinicopathologic features,immune infiltration,immune checkpoint,and tumor mutation burden(TMB)was further analyzed.In addition,a histogram was established based on the risk scores,and the drug sensitivity and prognostic value of lnc RNAs in pan-carcinoma were subsequently analyzed.Subsequently,the expression of m6 A gene in PTC was investigated by single cell sequencing technology,and the effect of PSMG3-AS1 on PTC was verified by cell functional experiments.Results: PTC patients were divided into two subtypes by 23 m6 A genes and 21 lnc RNAs with differential expression and prognostic correlation were screened.The prognosis,number of RAS mutations,number of BRAF mutations,M-stage and tumor microenvironment between subtypes were different between the two groups.The prognosis model included three lnc RNAs: PSMG3-AS1,BHLHE40-AS1 and AC016747.3.Risk scores were associated with cluster outcomes,PD-L1,tumor microenvironment,clinicopathologic features,immune cell infiltration,immune checkpoint,and tumor mutation load,and thus were identified as useful prognostic indicators.Single cell sequencing showed that ALKBH5 regulated by PSMG3-AS1 was significantly expressed in subcutaneous metastases of PTC.After stable knockout of PSMG3-AS1,the migration,proliferation and apoptosis of TPC-1,BCPAP and K1 cells were significantly decreased,and the ability of K1 cells to grow in vivo was also significantly inhibited.Conclusion: In this study,an m6A-related lnc RNA prognostic model was established and verified in PTC.PTC patients were divided into high and low risk groups by this risk scores,and the progression-free survival,immune checkpoint,immune microenvironment,clinicopathological features of high risk groups were significantly different.The value of this study is that the model can select high-risk patients with PTC for precision medicine.Finally,the important effect of PSMG3-AS1 on the malignant biological behavior of PTC was verified by molecular,cellular and animal experiments,suggesting that PSMG3-AS1 may be an important biomarker of PTC.