Effects of Estrogen-related Receptor alpha (ERRα) on Proliferation and Metastasis of Human Lung Cancer A549 Cells

Estrogen-related receptor alpha （ERRα） plays an important role in the development of hor- monezdependent cancers, but its roles in lung cancer remain elusive. The present study was aimed to investigate the effects of ERRα on the proliferation and metastasis of lung cancer A549 cells. The mRNA and protein levels of ERRor were detected in lung cancer A549 and MCF-7 cells and bronchial epithelial BEAS-2B cells by qRT-PCR and Western blotting, respectively. ERRor plasmid transfection and XCT-790 （an inverse agonist of ERRc0 were used to up-regulate or down-regulate ERRα expression in A549 cells, respectively. The viability of A549 cells was measured by cell counting kit-8 （CCK-8） and the motility of A549 cells by wound healing assay and Transwell migration/invasion assay. The epithelial markers E-cadherin （E-Cad） and zona occludin-1 （ZO-1）, the mesenchymal markers fi- bronectin （FN） and vimentin （Vim） and the transcription factors （Snail, Zebl Twist and Slug） were fur- ther detected at mRNA and protein levels by qRT-PCR and Western blotting, respectively. The results showed that ERRor promoted the growth of lung cancer A549 cells in vitro. XCT-790 significantly in- hibited the migration and invasion of A549 cells. Over-expression of ERRα promoted the epithe- lial-to-mesenchymal transition （EMT） of A549 ceils, down-regulated the epithelial makers E-Cad and ZO-1, and up-regulated the mesenchymal makers FN and Vim. Silencing of Slug, but not other tran- scription factors, significantly abolished the ERRs-induced EMT of A549 cells. It was suggested that ERRor promoted the migration and invasion of A549 cells by inducing EMT, and Slug was involved in the process. Targeting ERRor might be an efficient approach for lung cancer treatment.

Anticancer Effect of Icaritin on Human Lung Cancer Cells through Inducing S Phase Cell Cycle Arrest and Apoptosis

Icaritin, a prenylflavonoid derivative from Epimedium Genus, has been shown to exhibit many pharmacological and biological activities. However, the function and the underlying mechanisms of icaritin in human non-small cell lung cancer have not been fully elucidated. The purpose of this study was to investigate the anticancer effects of icaritin on A549 cells and explore the underlying molecular mechanism. The cell viability after icaritin treatment was tested by MTT assay. The cell cycle distribution, apoptosis and reactive oxygen species（ROS） levels were analyzed by flow cytometry. The mRNA and protein expression levels of the genes involved in proliferation and apoptosis were respectively detected by RT-PCR and Western blotting. The results demonstrated that icaritin induced cell cycle arrest at S phase, and down-regulated the expression levels of S regulatory proteins such as Cyclin A and CDK2. Icaritin also induced cell apoptosis characterized by positive Hoechst 33258 staining, accumulation of the Annexin V-positive cells, increased ROS level and alteration in Bcl-2 family proteins expression. Moreover, icaritin induced sustained phosphorylation of ERK and p38 MAPK. These findings suggested that icaritin might be a new potent inhibitor by inducing S phase arrest and apoptosis in human lung carcinoma A549 cells.