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With the development of technologies, multiple primary lung cancer (MPLC) has been detected more frequently. Although large-scale genomics studies have made significant progress, the aberrant gene mutation in MPLC is largely unclear. In this study, 141 and 44 lesions from single and multiple primary lung adenocarcinoma (SP- and MP-LUAD) were analyzed. DNA and RNA were extracted from formalin-fixed, paraffin-embedded tumor tissue and sequenced by using the next-generation sequencing-based YuanSu450TM gene panel. We systematically analyzed the clinical features and gene mutations of these lesions, and found that there were six genes differently mutated in MP-LUAD and SP-LUAD lesions, including RBM10, CDK4, ATRX, NTRK1, PREX2, SS18. Data from the cBioPortal database indicated that mutation of these genes was related to some clinical characteristics, such as TMB, tumor type, et al. Besides, heterogeneity analysis suggested that different lesions could be tracked back to monophyletic relationships. We compared the mutation landscape of MP-LUAD and SP-LUAD and identified six differentially mutated genes (RBM10, CDK4, ATRX, NTRK1, PREX2, SS18), and certain SNV loci in TP53 and EGFR which might play key roles in lineage decomposition in multifocal samples. These findings may provide insight into personalized prognosis prediction and new therapies for MP-LUAD patients.
RESUMO
Background: Amino acid metabolism participates in forming immunosuppressive tumor microenvironment. Amino acid transporters (AATs), as a gate for admission, remains to be studied. Materials and methods: We identified LUAD-specific prognostic AATs, SLC7A5 by differential expression analysis, logistic regression, machine learning, Kaplan-Meier analysis, AUC value filtrating and Cox regression. Then differential expression and distribution of SLC7A5 were depicted. Copy number variation, DNA methylation, transcriptional factors and ceRNA network were investigated to explore potential mechanism causing differential expression. The prognostic and clinical relation were evaluated by Kaplan-Meier analysis, Cox regression analysis. GSEA and GSVA were used to analyze altered pathways between SLC7A5 high- and low-groups. The expression of HLA-related genes and immune checkpoint genes, and immune cells infiltration were detected. SLC7A5 expression in immune cells was evaluated by single-cell sequencing data. IPS and an independent immunotherapy cohort assessed response rates of patients with distinct SLC7A5 expression. Proliferation assay and wound healing assay validated the effects of SLC7A5 on proliferation and migration of LUAD cells. Western blotting and cell viability assays were performed to detect mTORC1 pathway activity and sensitivity to rapamycin. Results: SLC7A5 was a LUAD-specific prognostic AAT and had significant differential expression in transcription and translation level. Methylation levels of cg00728300, cg00858400, cg12408911, cg08710629 were negative correlation with SLC7A5 expression. FOXP3 and TFAP2A were possible transcription factors and miR-30a-5p, miR-184, miR-195-5p may target SLC7A5 mRNA. SLC7A5 high-expression indicated poor prognosis and was an independent prognostic factor. mTORC1, cell cycle, DNA damage repair, response to reactive oxygen, angiogenesis, epithelial-mesenchymal transition (EMT) and various growth factors signaling pathways were activated in SLC7A5 high-expression group. Interestingly, SLC7A5 high-expression group had less immune-related genes expression and immune cells infiltration. Single-cell sequencing data also suggested SLC7A5 was downregulated in various T cells, especially effector T cells. Moreover, high SLC7A5 expression indicated poor immunotherapy efficacy and higher sensitivity to inhibitors of mTORC1 pathway, cell cycle and angiogenesis. SLC7A5 deficiency abrogated proliferation, migration and mTORC1 pathway activity. Conclusions: In summary, as a LUAD-specific prognostic AAT, SLC7A5 is involved in activation of multiple oncogenic pathways and indicates poor prognosis. Moreover, SLC7A5 may participate in forming immunosuppressive TME and is associated with low response of immunotherapy. SLC7A5 is promising to be a new diagnostic and prognostic biomarker and therapeutic target in LUAD.
