Effects of Emodin Extracted from Chinese Herbs on Proliferation of Non-small Cell Lung Cancer and Underlying Mechanisms

To aim of this was to observe emodin-mediated cytotoxicity and its influence on Rad51 and ERCC1 expressioninnon-small cell lung cancer (NSCLC). NSCLC cells were cultured in vitro with emodin at various concentrations(0, 25, 50, 75 and 100 μmol/L) for 48h and the proliferation inhibition rate was determined by the MTT method.Then, NSCLC were treated with emodin (SK-MES-1 40 μmol/L, A549 70 μmol/L) or 20 μmol/L U0126 (an ERKinhibitor) for 48 h, or with various concentrations of emodin for 48 h and the protein and mRNA expressionsof ERCC1 and Rad51 were determined by RT-PCR and Western blot assay, respectively. Emodin exerted asuppressive effect on the proliferation of NSCLC in a concentration dependent manner. Protein and mRNAexpression of ERCC1 and Rad51 was also significantly decreased with the dose. Vacuolar degeneration wasobserved in A549 and SK-MES-1 cell lines after emodin treatment by transmission electron microscopy. Emodinmay thus inhibited cell proliferation in NSCLC cells by downregulation ERCC1 and Rad51.