title: Autocrine regulation of TGF-β1-induced cell migration by exocytosis of ATP and activation of P2 receptors in human lung cancer cells.
abstract: 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. We show here that exocytosis of ATP followed by activation of P2 receptors play a key role in TGF-β1-induced actin remodeling associated with cell migration. Treatment with TGF-β1 facilitated migration of human lung cancer A549 cells, which was blocked by pretreatment with ecto-nucleotidase and P2 receptor antagonists. 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 cell migration, at least in part, through activation of P2X7 receptors. 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. We conclude that autocrine signaling through exocytosis of ATP and activation of P2 receptors is required for the amplification of TGF-β1-induced migration of lung cancer cells.
authors.affiliation: Department of Radiation Biosciences, Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda-shi Chiba 278-8510,  Japan.
authors.forename: Erina
authors.initials: E
authors.lastname: Takai
authors.forename: Mitsutoshi
authors.initials: M
authors.lastname: Tsukimoto
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Harada
authors.forename: Keisuke
authors.initials: K
authors.lastname: Sawada
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Moriyama
authors.forename: Shuji
authors.initials: S
authors.lastname: Kojima
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism*; D019898:Autocrine Communication; D045744:Cell Line, Tumor; D002465:Cell Movement; D005089:Exocytosis; D015870:Gene Expression; D055785:Gene Knockdown Techniques; D006801:Humans; D008175:Lung Neoplasms; D033704:Nucleotide Transport Proteins / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D018048:Receptors, Purinergic P2 / Q000235:genetics / Q000378:metabolism; D058486:Receptors, Purinergic P2X7 / Q000235:genetics / Q000378:metabolism*; D022142:Secretory Vesicles / Q000378:metabolism; D015398:Signal Transduction; D053773:Transforming Growth Factor beta1 / Q000502:physiology*
chemical_list: D033704:Nucleotide Transport Proteins; D034741:RNA, Small Interfering; D018048:Receptors, Purinergic P2; D058486:Receptors, Purinergic P2X7; C529437:Slc17a9 protein, human; D053773:Transforming Growth Factor beta1; D000255:Adenosine Triphosphate