GSE160671
An emerging epithelial to mesenchymal transition inducer: extracellular ATP activates and modulates EMT at levels of transcription, translation, and cell function independent of TGF-b
EMT is an early process in metastasis that is associated with up to 90% of cancer-related death. ATP has been known to play some roles in EMT. We previously described that internalization of extracellular ATP (eATP) by cancer cells in vitro and in vivo via macropinocytosis increases intracellular ATP levels, cell proliferation and resistance to anticancer drugs. Recently, we reported eATP also induces EMT and other early metastatic activities independent of TGF-b, a well-known inducer of EMT, in human lung cancer cells. However, exactly how eATP induces EMT at gene expression level is far from understood. In this study, we hypothesize that eATP acts as an inducer and regulator of EMT alternative to TGF-b. Transwell assays revealed that eATP treatment, alone, induced human lung cancer A549 and H1299 cells to invade at rates faster than TGF-b. eATP also induced formation of filopodia-like protrusions faster than TGF-b, and it restored viability of cancer cells treated with TGF-b-neutralizing antibodies. eATP significantly elevated intracellular ATP levels while TGF-b did not. RNA sequencing / western blots revealed that eATP induced changes in expression of genes/proteins involved in EMT similar to but with differences in number and induction time compared with those induced by TGF-b. Metabolomics analysis shows that eATP-induced major metabolic changes are consistent/correlated with those identified at the gene expression level.  These differences could be accounted for by the multi-functional and multi-localization properties of eATP and macropinocytosis-internalized eATP, strongly suggesting that eATP is a previously unrecognized master inducer and regulator of EMT. Overall design: Total 5 conditions are included, they are 2h ATP treatment, 2h TGF-ß treatment, 6h ATP treatment, 6h TGF-ß treatment and control. For each treatment conditions, four replicates are performed.