Analysis Of Proteome And Phosphoproteome In Relation Of Lymph Node Metastasis Of Lung Adenocarcinoma Basing On Mass Spectrometry

Objective Lung adenocarcinoma(LUAD)is one of the most malignant tumors.For some patients with LUAD,lymph node metastasis occurs when the tumor size is small.Proteins are the executors of life functions.Hence,it is of great clinical value to explore the proteins related to lymph node metastasis in patients with LUAD.In this study,mass spectroscopy-based proteomics was used to explore the key proteins and pathways of lymph node metastasis in LUAD,and protein molecular typing was tried to be established.Methods In this study,52 patients with LUAD were enrolled and their clinical data were collected.Among them,25 patients in the experimental group(LUAD with lymph node metastasis,pathological stage of T1 b N2M0)and 27 patients in the control group(LUAD with no lymph node metastasis,pathological stage of T3-4N0M0)were enrolled.Frozen tumor samples and normal lung tissue samples from 52 patients tested,proteins were identified and quantified by4d-lfq quantitative proteomics technique based on mass spectrometry.Moreover,due to the limitation of the samples’ sizes,protein phosphorylation modification omics was tested in 42patients’ samples.Differentially expressed quantity was set to 2 as the threshold for significant up-regulation,and 1/2 as the threshold for significant down-regulation.We screened the differentially expressed proteins and phosphorylation modification sites of tumor samples and normal samples,and of the experimental and normal group samples,and did their subcellular localization,structural domain analysis,GO functional annotations and KEGG pathway enrichment analysis.Key proteins were screened by protein interaction network,and protein molecular typing and prognosis were analyzed.Results The frequency of EGFR mutation was higher in the experimental group,while the frequency of smoking was higher in the control group.There was no significant difference in DFS and OS between the two groups(P > 0.05).There were 740 up-regulated proteins and 382down-regulated proteins in the tumor compared with the normal tissues,and 89 up-regulated proteins and 155 down-regulated proteins in the tumor samples of the experimental group compared with the control group.GO functional annotation and KEGG pathway enrichment showed the high metabolic characteristics of tumor tissues,especially the metabolism of various amino acids.Extracellular matrix,adhesion plaque pathway and pi3k-akt pathway may play important roles in lymph node metastasis.The core proteins associated with lymph node metastasis are mainly collagen,laminin and other proteins involved in the synthesis and assembly of extracellular matrix fibers.Protein subgroups divided patients into 3 groups,which were associated with better prognosis,although the statistical difference was not significant(P=0.088).Conclusions Through proteomics,multiple pathways and proteins related to LUAD formation and lymph node metastasis were found in this study,which provides a promising target for tumor treatment in future.Protein subgroups are beneficial supplements to the clinical phenotype and potential prognostic factors,which can provide therapeutic strategies for individualized treatment.