LINC00355 promoted the progression of lung squamous cell carcinoma through regulating the miR-466/LYAR axis

LINC00355 has been reported aberrantly over-expressed and associated with poor prognosis in various types of cancer. However, reports regarding the effect of LINC00355 on lung squamous cell carcinoma (SCC) are rare. This study aimed to explore the function of LINC00355 in the development and progression of lung SCC and reveal the underlying mechanism. The expression and subcellular location of LINC00355 were determined by qRT-PCR and RNA-FISH, respectively. The lung SCC cell growth was analyzed by CCK-8 assay, transwell invasion, wound healing, colony formation, and flow cytometry assays. Reactive oxygen species level was evaluated by DCFH-DA probes. Bioinformatics online websites, luciferase reporter assay, RNA binding protein immunoprecipitation (RIP), and RNA pull-down assays were utilized to investigate the interaction among LINC00355, miR-466, and Ly-1 antibody reactive clone (LYAR). The results showed that LINC00355 was upregulated in lung SCC and was positively associated with poor overall survival in lung SCC patients. LINC00355 was mainly located in the cytoplasm of SCC cells. Additionally, LINC0035 functioned as a competing endogenous RNA (ceRNA) to target miR-466, and LYAR was identified as a direct target of miR-466. LINC00355 expression negatively correlated with miR-466 level, and positively correlated with LYAR level. Mechanistically, knockdown of LINC00355 inhibited cell proliferation, migration and invasion, promoted cell apoptosis in vitro, and suppressed tumor growth in vivo through targeting miR-466, and thus down-regulated LYAR expression. These findings provide a new sight for understanding the molecular mechanism of lung SCC and indicate that LINC00355 may serve as a potential biomarker for the diagnosis and treatment of lung SCC.

LINC00355已被报道在多种癌症中异常高表达，且与不良预后密切相关。然而，目前关于LINC00355对肺鳞状细胞癌（SCC）的作用的研究报道较为少见。
本研究旨在探讨LINC00355在肺鳞状细胞癌发生发展中的功能，并揭示其潜在分子机制。
通过实时荧光定量逆转录聚合酶链反应（qRT-PCR）检测LINC00355的表达水平，采用RNA荧光原位杂交（RNA-FISH）确定其亚细胞定位。利用细胞计数试剂盒-8（CCK-8）实验、Transwell侵袭实验、划痕愈合实验、集落形成实验及流式细胞术分析肺鳞状细胞癌细胞的增殖、迁移与侵袭能力。采用2',7'-二氯荧光素二乙酸酯（DCFH-DA）探针检测细胞活性氧水平。通过生物信息学在线网站、荧光素酶报告基因实验、RNA结合蛋白免疫沉淀（RIP）实验及RNA下拉实验，探究LINC00355、miR-466与Ly-1抗体反应克隆（LYAR）三者间的相互作用。
研究结果显示，LINC00355在肺鳞状细胞癌组织中呈高表达，且与肺鳞状细胞癌患者的不良总生存期呈正相关。LINC00355主要定位于肺鳞状细胞癌细胞的细胞质中。此外，LINC00355可作为竞争性内源RNA（ceRNA）靶向结合miR-466，LYAR被证实为miR-466的直接靶基因。LINC00355的表达水平与miR-466的表达呈负相关，与LYAR的表达呈正相关。
机制研究表明，敲低LINC00355可通过靶向miR-466抑制肺鳞状细胞癌细胞的增殖、迁移与侵袭，促进细胞凋亡，并在体内抑制肿瘤生长，进而下调LYAR的表达。
本研究结果为阐明肺鳞状细胞癌的分子机制提供了新的视角，同时提示LINC00355有望成为肺鳞状细胞癌诊断与治疗的潜在生物标志物。