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

J Thorac Oncol. 2016 Dec;11(12):2173-2182. doi: 10.1016/j.jtho.2016.07.015. Epub 2016 Aug 2.

Abstract

Introduction: 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.

Methods: 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.

Results: 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.

Conclusions: Our findings suggest that lincRNA-p21 affects outcome in patients with NSCLC adenocarcinoma through the regulation of angiogenesis.

Keywords: Angiogenesis; Hypoxia; LincRNA-p21; Long noncoding RNAs; NSCLC.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Carcinoma, Non-Small-Cell Lung / genetics*
  • Carcinoma, Non-Small-Cell Lung / pathology
  • Cell Line, Tumor
  • Female
  • Gene Expression Profiling / methods
  • Humans
  • Lung Neoplasms / genetics*
  • Male
  • Middle Aged
  • Prognosis
  • Proto-Oncogene Proteins p21(ras) / genetics*
  • RNA, Long Noncoding / genetics*
  • RNA, Long Noncoding / metabolism
  • Transfection

Substances

  • RNA, Long Noncoding
  • Proto-Oncogene Proteins p21(ras)