Department of Thoracic and Cardiovascular Surgery, The Second People's Hospital of Neijiang, Neijiang, Sichuan, China.
Department of Thoracic and Cardiovascular Surgery, People's Hospital of Deyang, Deyang, Sichuan, China.
PeerJ. 2024 Aug 23;12:e17816. doi: 10.7717/peerj.17816. eCollection 2024.
Lymphocyte antigen 9 (LY9) participates in the development of several tumors and diseases but has not been reported yet in lung adenocarcinoma (LUAD).
First, we analyzed the expression and prognostic value of LY9 in pan-cancer, including LUAD. Additionally, we conducted a correlation analysis of LY9 expression in LUAD with immune cell infiltration using the TIMER database and the CIBERSORT algorithm, and with immune checkpoints using the GEPIA database. Also, we constructed a potential ceRNA network for LY9. Furthermore, we explored LY9-related pathways by Gene Set Enrichment Analysis (GSEA). Finally, validation of differential expression at the mRNA level was obtained from the GEO database. We collected LUAD tissues for Quantitative Real-time PCR (qRT-PCR) to verify the expression of LY9, CD8, and CD4 and calculated the correlation between them. We also conducted immunohistochemistry (IHC) to verify the protein expression of LY9.
Results showed that LY9 was highly expressed in various tumors, including LUAD. Besides, patients with high LY9 expression presented longer overall survival (OS) and more multiple lymphocyte infiltrations. The expression of LY9 in LUAD strongly and positively correlates with multiple immune cell infiltration and immune checkpoints. The functional enrichment analysis indicated that LY9 was involved in multiple immune-related pathways and non-small cell lung cancer. Moreover, a ceRNA regulatory network of LINC00943-hsa-miR-141-3p-LY9 might be involved. Finally, GSE68465 dataset confirmed differential expression of LY9 mRNA levels in LUAD and the qRT-PCR results verified LY9 had a strong and positive correlation with CD4 and CD8 T cells. Unfortunately, IHC did not detect the expression of LY9 protein level in tumor tissues and WB experiments validated the protein expression of LY9 in the OCI-AML-2 cell line.
Therefore, we hypothesized that LY9 could serve as a potential, novel prognostic biomarker for LUAD and could predict immunotherapy efficacy at the mRNA level.
淋巴细胞抗原 9（LY9）参与了几种肿瘤和疾病的发生，但尚未在肺腺癌（LUAD）中报道。
首先，我们分析了 LY9 在包括 LUAD 在内的泛癌中的表达和预后价值。此外，我们使用 TIMER 数据库和 CIBERSORT 算法对 LUAD 中 LY9 表达与免疫细胞浸润进行了相关性分析，并使用 GEPIA 数据库对免疫检查点进行了相关性分析。此外，我们构建了 LY9 的潜在 ceRNA 网络。然后，我们通过基因集富集分析（GSEA）探索了 LY9 相关通路。最后，从 GEO 数据库中获得了差异表达的验证。我们收集 LUAD 组织进行定量实时 PCR（qRT-PCR）以验证 LY9、CD8 和 CD4 的表达，并计算它们之间的相关性。我们还进行了免疫组化（IHC）以验证 LY9 的蛋白表达。
结果表明，LY9 在多种肿瘤中高表达，包括 LUAD。此外，高 LY9 表达的患者具有更长的总生存期（OS）和更多的多淋巴细胞浸润。LUAD 中 LY9 的表达与多种免疫细胞浸润和免疫检查点呈强烈正相关。功能富集分析表明，LY9 参与了多种免疫相关途径和非小细胞肺癌。此外，可能涉及 LINC00943-hsa-miR-141-3p-LY9 的 ceRNA 调控网络。最后，GSE68465 数据集证实了 LUAD 中 LY9 mRNA 水平的差异表达，qRT-PCR 结果验证了 LY9 与 CD4 和 CD8 T 细胞呈强烈正相关。遗憾的是，IHC 未检测到肿瘤组织中 LY9 蛋白水平的表达，WB 实验验证了 OCI-AML-2 细胞系中 LY9 的蛋白表达。
因此，我们假设 LY9 可作为 LUAD 的潜在新型预后生物标志物，并可预测免疫治疗在 mRNA 水平上的疗效。
