Knockdown of Med19 Enhances Chemo-sensitivity to Cisplatin in NSCLC Cells

Non-small cell lung cancer (NSCLC), a malignant tumor type with a high rate of relapse and metastasis, is the leading cause of cancer-related deaths worldwide. Despite aggressive approaches to treatment of lung cancer, the prognosis of NSCLC patients is still poor, with a 5-year survival rate of 5-14% (Khuri et al., 2001). This is usually due to the fact that most patients with this disease receive a late diagnosis and experience a relapse because of the chemoresistance (Rosell et al., 2006; Jang et al., 2009). Therefore, there is an urgent need to identify novel prognostic marker and therapeutic target for NSCLC. The mediator (Med) complex, an essential component of the RNA polymerase II (pol II)-mediated transcription complex, plays a crucial role in the stimulation of basal transcription and regulation of eukaryotic mRNA synthesis, which underpins cell proliferation, development, differentiation, and maintenance (Conaway et al., 2005; Conaway et al., 2005; Casamassimi et al., 2007). Med is a crescent-shaped complex consisting of head, middle, tail modules and highly conserved from yeast to mammals in evolution (Boube et al., 2002). As a multi-protein coactivator, Med consists of about 30 subunits that can interact with transcriptional activators, such as p53, SP1 and VP16 (Malik et al., 2005; Vojnic et al., 2011). Human Med19 gene, also known as “lung cancer metastasis related