<i>Ang-2</i> promotes lung cancer metastasis by increasing epithelial-mesenchymal transition

Abstract

Lung cancer is the most common malignant tumor with increasing angiopoietin-2 (Ang-2) and a high rate of metastasis. However, the mechanism of Ang-2 enhancing tumor proliferation and facilitating metastasis remains to be clarified. In this study, Ang-2 expression and its gene transcription on effects of biological behaviors and epithelial-mesenchymal transition (EMT) were investigated in lung cancers. Total incidence of Ang-2 expression in the cancerous tissues was up to 91.8 % (112 of 122) with significantly higher (χ²=103.753, <i>P</i>²=7.883, <i>P</i>=0.005), differentiation degree (χ²=4.554, <i>P</i>=0.033), tumor node metastasis (TNM) staging (χ²=5.039, <i>P</i>=0.025), and 5-year survival rate (χ² =11.220, <i>P</i>²=18.881, <i>P</i>²=0.81, <i>P</i>=0.776) or III & IV (χ²=1.845, <i>P</i>=0.174). Over-expression of Ang-2 or Ang-2 mRNA in lung A549 and NCI-H1975 cells were identified among different cell lines. When silencing <i>Ang-2</i> in A549 cells with specific shRNA-1 transfection, the cell proliferation was significantly inhibited in a time-dependent manner, with up-regulating E-cadherin, down-regulating Vimentin, Twist, and Snail expression, and decreasing invasion and metastasis of cancer cell abilities, suggesting that <i>Ang-2</i> promote tumor metastasis through increasing EMT, and it could be a potential target for lung cancer therapy.