Zhou Jiazhen, Jiang Guanqing, Xu Enwu, Zhou Jiaxin, Liu Lili, Yang Qiaoyuan
The Institute for Chemical Carcinogenesis, School of Public Health, Guangzhou Medical University, Guangzhou, China.
Department of Thoracic Surgery, General Hospital of Southern Theater Command, People's Liberation Army (PLA), Guangzhou, China.
Front Oncol. 2022 Jan 5;11:810301. doi: 10.3389/fonc.2021.810301. eCollection 2021.
Lung cancer is the leading cause of cancer-related mortality worldwide. Although cigarette smoking is an established risk factor for lung cancer, few reliable smoking-related biomarkers for non-small-cell lung cancer (NSCLC) are available. An improved understanding of these biomarkers would further the development of new biomarker-targeted therapies and lead to improvements in overall patient survival.
We performed bioinformatic analysis to screened potential target genes, then quantitative PCR, western, siRNA, CCK-8, flow cytometry, tumorigenicity assays in nude mice were performed to validated the function.
In this study, we identified 83 smoking-related genes (SRGs) based on an integration analysis of two Gene Expression Omnibus (GEO) datasets, and 27 hub SRGs with potential carcinogenic effects by analyzing a dataset of smokers with NSCLC in The Cancer Genome Atlas (TCGA) database. A survival analysis revealed three genes with potential prognostic value, namely SRXN1, KRT6A and JAKMIP3. A univariate Cox analysis revealed significant associations of elevated SRXN1 and KRT6A expression with prognosis. A receiver operating characteristic (ROC) curve analysis indicated the high diagnostic value of SRXN1 and KRT6A for smoking and cancer. Quantitative PCR and western blotting validated the increased expression of SRXN1 and KRT6A mRNA and protein, respectively, in lung cancer cell lines and NSCLC tissues. In patients with NSCLC, SRXN1 and KRT6A expression was associated with the tumor-node-metastasis (TNM) stage, presence of metastasis, history of smoking and daily smoking consumption. Furthermore, inhibition of SRXN1 or KRT6A suppressed viability and enhanced apoptosis in the A549 human lung carcinoma cell line. Tumorigenicity assays in nude mice confirmed that the siRNA-mediated downregulation of SRXN1 and KRT6A expression inhibited tumor growth .
In summary, SRXN1 and KRT6A act as oncogenes in NSCLC and might be potential biomarkers of smoking exposure and the early diagnosis and prognosis of NSCLC in smokers, which is vital for lung cancer therapy.
肺癌是全球癌症相关死亡的主要原因。尽管吸烟是肺癌公认的危险因素，但针对非小细胞肺癌（NSCLC）的可靠吸烟相关生物标志物却很少。对这些生物标志物的深入了解将推动新的生物标志物靶向治疗的发展，并改善患者的总体生存率。
我们进行了生物信息学分析以筛选潜在的靶基因，然后进行定量PCR、蛋白质印迹、小干扰RNA（siRNA）、细胞计数试剂盒-8（CCK-8）、流式细胞术以及裸鼠致瘤性试验以验证其功能。
在本研究中，我们基于对两个基因表达综合数据库（GEO）数据集的整合分析，鉴定出83个吸烟相关基因（SRG），并通过分析癌症基因组图谱（TCGA）数据库中NSCLC吸烟者的数据集，确定了27个具有潜在致癌作用的核心SRG。生存分析显示，有三个基因具有潜在的预后价值，即硫氧还蛋白1（SRXN1）、角蛋白6A（KRT6A）和接头蛋白含Jak同源结构域和MIP结构域3（JAKMIP3）。单变量Cox分析显示，SRXN1和KRT6A表达升高与预后显著相关。受试者工作特征（ROC）曲线分析表明，SRXN1和KRT6A对吸烟和癌症具有较高的诊断价值。定量PCR和蛋白质印迹分别验证了肺癌细胞系和NSCLC组织中SRXN1和KRT6A mRNA及蛋白质表达的增加。在NSCLC患者中，SRXN1和KRT6A表达与肿瘤-淋巴结-转移（TNM）分期、转移情况、吸烟史和每日吸烟量有关。此外，抑制SRXN1或KRT6A可抑制A549人肺癌细胞系的活力并增强其凋亡。裸鼠致瘤性试验证实，siRNA介导的SRXN1和KRT6A表达下调可抑制肿瘤生长。
总之，SRXN1和KRT6A在NSCLC中起癌基因作用，可能是吸烟暴露以及吸烟者NSCLC早期诊断和预后的潜在生物标志物，这对肺癌治疗至关重要。
