Increased expression of monoamine oxidase A is associated with epithelial to mesenchymal transition and clinicopathological features in non-small cell lung cancer

Monoamine oxidase A (MAOA), a mitochondrial enzyme, is closely associated with neurological disorders. Recently, MAOA has been linked to the progression of prostate cancer, hepatocellular carcinoma, and cholangio-carcinoma. However, MAOA was reported to have different effects on the progression of these types of cancer, and the role of MAOA in non-small cell lung cancer (NSCLC) progression remains unclear. The present study determined the expression of MAOA and epithelial to mesenchymal transition (EMT) markers in 45 pairs of NSCLC and matched non-tumor adjacent lung tissues, and further analyzed the correlation between MAOA expression and the EMT or the development of clinicopathological features. The results demonstrated that protein and mRNA expression levels of MAOA in NSCLC tissues were higher than those observed in the matched non-tumor adjacent lung tissues. Furthermore, the increased MAOA expression in NSCLC tissues was positively correlated with N-cadherin (r = 0.525, P = 0.002), Slug (r = 0.515, P = 0.001), and Twist (r = 0.448, P = 0.008) expressions, but negatively correlated with E-cadherin expression (r = -0.387, P = 0.01). Additionally, the elevated MAOA expression in NSCLC tissues was associated with late stage NSCLC (Z = -2.596, P = 0.029) and lymph node metastases (Z = -2.378, P = 0.020). These findings suggest that MAOA may have a role in promoting NSCLC progression by mediating EMT.