Abstract 3156: Autocrine signaling through release of ATP and activation of P2X7 receptor promotes migration of human lung cancer cells

Abstract

Abstract Cell migration is essential step of cancer metastasis. TGF-β1 plays a key role in cancer progression through induction of various biological effects, including cell migration. Extracellular nucleotides, such as ATP, released from cells play a role in signaling through activation of P2 receptors. However, it remains poorly understood whether ATP-P2 receptor signaling is involved in cancer progression. We show here that release of ATP followed by activation of P2X7 receptors plays a key role in migration of lung cancer cells. Treatment with TGF-β1 facilitated migration of human lung cancer A549 cells, which was blocked by pretreatment with ecto-nucleotidase and P2 receptor antagonists in a wound healing-based assay and Transwell assay. ATP and P2 agonists facilitated cell migration. TGF-β1-induced actin remodeling, which contributes to cell migration, was also suppressed by pretreatment with ecto-nucleotidase and P2 receptor antagonists. Knockdown of P2X7 receptor suppressed TGF-β1-induced migration and actin remodeling. These results indicate the involvement of TGF-β1-induced ATP release in cancer cell migration, at least in part, through activation of P2X7 receptors. We found that TGF-β1 caused release of ATP from A549 cells within 10 minutes. Both ATP-enriched vesicles and expression of a vesicular nucleotide transporter (VNUT) SLC17A9, which is responsible for exocytosis of ATP, were found in cytosol of A549 cells. TGF-β1 failed to induce release of ATP from SLC17A9-knockdown cells. TGF-β1-induced cell migration and actin remodeling were also decreased in SLC17A9-knockdown cells. These results suggest the importance of exocytosis of ATP in cell migration. In addition, treatment with specific antagonist of P2X7 receptor (A438079) suppressed TGF-β1-induced migration of another human lung cancer H292 cells, but not of non-cancerous BEAS-2B cells. H292 cells released ATP in response to TGF-β1 stimulation, while BEAS-2B cells did not. Furthermore, in high-motile human lung cancer PC-9 cells, a large amount of ATP was released under standard cell culture condition, and P2X7 receptor was constitutively activated. Blockade of P2X7 receptor significantly suppressed motile activity of PC-9 cells. Taken together, these results suggest that autocrine signaling through release of ATP and activation of P2X7 receptor play a role in migration of human lung cancer cells. Citation Format: Erina Takai, Mitsutoshi Tsukimoto, Hitoshi Harada, Miki Hiasa, Yoshinori Moriyama, Shuji Kojima. Autocrine signaling through release of ATP and activation of P2X7 receptor promotes migration of human lung cancer cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3156. doi:10.1158/1538-7445.AM2014-3156