Profiling premalignant lesions in lung squamous cell carcinomas identifies mechanisms involved in stepwise carcinogenesis

Lung squamous cell carcinoma (SCC) is thought to arise from premalignant lesions in the airway epithelium, therefore studying these lesions is critical for understanding lung carcinogenesis. We performed RNA sequencing on laser-microdissected representative cell populations along the SCC pathological continuum of patient-matched normal basal cells, premalignant lesions, and tumor cells. We discovered transcriptomic changes and identified genomic pathways altered with initiation and progression of SCC within individual patients. We used immunofluorescent staining to confirm gene expression changes in premalignant lesions and tumor cells, including increased expression of SLC2A1, CEACAM5, and PTBP3 at the protein level and increased activation of MYC via nuclear translocation. Cytoband enrichment analysis revealed coordinated loss and gain of expression in chromosome 3p and 3q regions, respectively, during carcinogenesis. This is the first gene expression profiling of airway premalignant lesions with patient-matched samples that provides insight into the mechanisms of stepwise lung carcinogenesis. Profiling of mRNA expression in laser-microdissected normal airway basal cells, premalignant airway lesions, and lung SCC tumor cells by massively parallel RNA sequencing.

肺鳞状细胞癌（Lung squamous cell carcinoma, SCC）被认为起源于气道上皮的癌前病变，因此对这类病变的研究对于理解肺癌变过程具有关键意义。本研究针对患者匹配的正常气道基底细胞、癌前病变及肿瘤细胞，沿肺鳞状细胞癌的病理连续谱系，对代表性激光显微切割细胞群开展了RNA测序（RNA sequencing）。本研究鉴定了转录组层面的变化，并明确了个体患者体内肺鳞状细胞癌起始与进展过程中发生异常改变的基因组通路。通过免疫荧光染色验证了癌前病变与肿瘤细胞中的基因表达变化，包括蛋白水平上SLC2A1、CEACAM5及PTBP3的表达上调，以及MYC通过核易位实现的激活增强。细胞带富集分析显示，在癌变进程中，3号染色体短臂（3p）与长臂（3q）区域分别出现协同性的表达丢失与获得。本研究是首个采用患者匹配样本开展的气道癌前病变基因表达谱分析，为阐明逐步肺癌变的分子机制提供了重要见解。本研究通过大规模并行RNA测序（massively parallel RNA sequencing），对激光显微切割获取的正常气道基底细胞、气道癌前病变及肺鳞状细胞癌肿瘤细胞的mRNA表达进行了谱学分析。