PPARGC1A is upregulated and facilitates lung cancer metastasis

Lung cancer remains a leading cause of cancer-related mortality, with metastatic progression remaining the single largest cause of lung cancer mortality. Hence it is imperative to determine reliable biomarkers for lung cancer prognosis. We performed quantitative real-time PCR (qRT-PCR) analysis to explore epithelial-mesenchymal transition (EMT) inducers that regulate EMT process in three patients with advanced lung cancer disease. Peroxisome proliferator-activated receptor gamma (PPARGC1A) was uniformly the topmost overexpressed gene in all three human non-small cell lung cancer (NSCLC) patient samples. Further evaluation in human normal lung and metastatic lung cancer cell lines revealed that the expression of PPARGC1A was upregulated in metastatic lung cancer cell lines. Metagenomic analysis revealed direct correlation among PPARGC1A, zinc-finger transcription factor snail homolog 1 (SNAI1), and metastatic lung disease. Upregulation of PPARGC1A transcript expression was independent of a differential upregulation of the upstream AMP-dependent protein kinase (AMPK) activation or steady state expression of the silent mating type information regulation 2 homolog 1 (SIRT1). Xenograft tail vein colonization assays proved that the high expression of PPARGC1A was a prerequisite for metastatic progression of lung cancer to brain. Our results indicate that PPARGC1A might be a potential biomarker for lung cancer prognosis.