Clinical Significance Of ACSM5 In Lung Adenocarcinoma And Its Correlation With Immune Infiltration

Objective: To explore the clinical significance of ACSM5(Acyl-Coenzyme A synthetase medium chain family 5)in lung adenocarcinoma and its correlation with immune invasion.Methods: In this study,we analyzed the database of TCGA(The Cancer Genome Atlas)to explore the expression level of ACSM5 in lung adenocarcinoma and its correlation with survival,prognosis and clinicopathological parameters,and preliminarily confirmed that ACSM5 is a key gene in the development and evolution of lung adenocarcinoma.Then GSEA(Gene Set Enrichment Analysis)software was used to analyze the potential molecular pathways related to ACSM5.The positive and negative expressions of genes encoded by ACSM5-related proteins in LUAD tissues were analyzed by UALCN(The University of Alabama Cancer Database)database.Using STRING and Gene MANIA databases,we investigated the protein coding genes associated with ACSM5 in LUAD tissues.We also determined the correlation between ACSM5 and 28 kinds of tumor infiltrating immune cells by using CIBERSORT and TCGA databases.Through TIMER algorithm,we analyzed the correlation between ACSM5 and immune cell markers,and used "GSVA"(version 1.40.1)and "gsease"(version 1.544.0)R packets to analyze the correlation between ACSM5 and immune cell function.After preliminary analysis using lung adenocarcinoma online database,clinical samples were used to verify the above results.Western Blot and Immunohistochemistry were used to verify the correlation between the expression of ACSM5 and survival prognosis,clinicopathological parameters and immune checkpoint PD-1,PD-L1.Results: In TCGA database,the expression of ACSM5 was significantly lower in18 kinds of cancers,such as BLCA(Bladder Urothelial Carcinoma),BRCA(Breast Invasive Carcinoma)and CHOL(Cholangiocarcinoma).The expression of ACSM5 in lung adenocarcinoma was also significantly lower than that in normal tissues in WB and IHC.Prognostic analysis showed that patients with high expression of ACSM5 had better prognosis than patients with low expression of ACSM5 in lung adenocarcinoma.Then to explore the correlation between ACSM5 and clinical factors of lung adenocarcinoma,the results of box diagram show that the expression of ACSM5 is closely related to the clinicopathological grade,and with the increase of pathological grade and T stage,the expression of ACSM5 is also decreasing.Univariate COX regression analysis showed that grade(HR=1.65,P < 0.001),T stage(HR=1.63,P <0.001),lymph metastasis(HR=1.79,P < 0.001)and ACSM5 expression(HR=0.11,P <0.001)were associated with OS.Multivariate COX regression analysis showed that ACSM5 could be used as an independent risk factor for the prognosis of patients with lung adenocarcinoma.The genes related to ACSM5 in LUAD tissues were analyzed by UALCAN database.The results showed that the top 10 protein coding genes with positive correlation with ACSM5 were DPEP2,KCNJ5,DNASE2 B,FDG2,IRF8,CHIT1,CD37,MS4A7,AMICA1 and CD300 LF.The 10 protein coding genes negatively related to ACSM5 are PAICS,ALDH18A1,HDGF,CKAP4,UBE2V2,PYCR1,FAM136 A,TUBA1C,BZW2 and PPP1R14 B.Then we analyzed the KEGG pathway by GSEA software to determine the biological pathways related to the expression of ACSM5 in the progression of lung adenocarcinoma.The results showed that the high expression of ACSM5 may be positively correlated with intestinal immune network for Ig A production,cell adhesion molecules CAMs,B cell receptor signal pathway,natural killer cell mediated cytotoxicity,T cell receptor signal pathway and VEGF signal pathway.The high expression of ACSM5 may be negatively correlated with RNA degradation,cell cycle,pentose phosphate pathway,protein export and citric cycle TCA cycle.Through CIBERSORT and TCGA databases,It was found that the expression of ACSM5 was significantly correlated with 24 types of immune cells.TIMER database was used to further explore the relationship between the level of immune cell infiltration,prognosis and ACSM5 expression in LUAD tissues.The results showed that the expression level of ACSM5 was positively correlated with the infiltration level of CD4+T cells(r = 0.311,P = 1.49e-12),B cells(r = 0.181,P =5.11e-05)and neutrophils(r = 0.24,P = 6.52e-08).The infiltration level of B cells and dendritic cells and the expression of ACSM5 were related to the cumulative survival rate of LUAD.The R packet analysis of "GSVA"(version 1.40.1)and "gsease"(version 1.544.0)showed that the high expression of ACSM5 was related to the immune checkpoints of PD-1,PD-L1,CTLA4,CD86,LAG3,TIM-3 and TIGIT in LUAD tissues.The results of immunohistochemical showed that the expression of ACSM5 decreased gradually with the increase of T stage,and the expression of ACSM5 was positively correlated with prognosis.Multivariate COX analysis showed that ACSM5 could be used as an independent prognostic factor in patients with lung adenocarcinoma,which was consistent with the previous results.In addition,the high abundance of ACSM5+ cell infiltration is related to the high abundance of PD-L1+ and PD-1+ in the tumor.Conclusion: 1.The expression of ACSM5 was low in lung adenocarcinoma.2.The expression of ACSM5 decreased with the increase of T stage in patients with lung adenocarcinoma.3.ACSM5 can be used as an independent biomarker for prognosis of lung adenocarcinoma patients.4.The high abundance of ACSM5 + cell infiltration is related to the high abundance of PD-L1+ and PD-1+ in patients with lung adenocarcinoma.