LincRNA-p21 Impacts Prognosis in Resected Non–Small Cell Lung Cancer Patients through Angiogenesis Regulation

• Published in: Journal of thoracic oncology 2016-12, Vol.11 (12), p.2173-2182
• Main Authors: Castellano, Joan J., Navarro, Alfons, Viñolas, Nuria, Marrades, Ramon M., Moises, Jorge, Cordeiro, Anna, Saco, Adela, Muñoz, Carmen, Fuster, Dolors, Molins, Laureano, Ramirez, Josep, Monzo, Mariano
• Format: Article
• Language: English
• Subjects: Adult; Aged; Aged, 80 and over; Angiogenesis; Carcinoma, Non-Small-Cell Lung - genetics; Carcinoma, Non-Small-Cell Lung - pathology; Cell Line, Tumor; Female; Gene Expression Profiling - methods; Humans; Hypoxia; LincRNA-p21; Long noncoding RNAs; Lung Neoplasms - genetics; Male; Middle Aged; NSCLC; Prognosis; Proto-Oncogene Proteins p21(ras) - genetics; RNA, Long Noncoding - genetics; RNA, Long Noncoding - metabolism; Transfection
• ISSN: 1556-0864; 1556-1380
• DOI: 10.1016/j.jtho.2016.07.015

Long intergenic noncoding RNA-p21 (lincRNA-p21) is a long noncoding RNA transcriptionally activated by tumor protein p53 (TP53) and hypoxia inducible factor 1 alpha subunit (HIF1A). It is involved in the regulation of TP53-dependent apoptosis and the Warburg effect. We have investigated the role of lincRNA-p21 in NSCLC. LincRNA-p21 expression was assessed in tumor and normal tissue from 128 patients with NSCLC and correlated with time to relapse and cancer-specific survival (CSS). H23, H1299, and HCC-44 cell lines were cultured in hypoxic conditions after silencing of lincRNA-p21. The TaqMan human angiogenesis array was used to explore angiogenesis-related gene expression. Levels of the protein vascular endothelial growth factor A were measured by enzyme-linked immunosorbent assay in the cell supernatants. Angiogenic capability was measured by human umbilical vein endothelial cell tube formation assay. Microvascular density in tumor samples was analyzed by immunohistochemistry. LincRNA-p21 was down-regulated in tumor tissue, but no association was observed with TP53 mutational status. High lincRNA-p21 levels were associated with poor CSS in all patients (p = 0.032). When patients were classified according to histological subtypes, the impact of lincRNA-p21 was confined to patients with adenocarcinoma in both time to relapse (p = 0.006) and CSS (p < 0.001). To explain the poor outcome of patients with high lincRNA-p21 expression, we studied the role of lincRNA-p21 in angiogenesis in vitro and observed a global downregulation in the expression of angiogenesis-related genes when lincRNA-p21 was inhibited. Moreover, supernatants from lincRNA-p21–inhibited cells were significantly less angiogenic and had lower levels of secreted vascular endothelial growth factor A than controls did. Finally, tumor samples with high lincRNA-p21 levels had higher microvascular density. Our findings suggest that lincRNA-p21 affects outcome in patients with NSCLC adenocarcinoma through the regulation of angiogenesis.