title: The actin-sequestering protein thymosin beta-4 is a novel target of hypoxia-inducible nitric oxide and HIF-1α regulation.
abstract: The actin-sequestering protein thymosin beta-4 (Tβ4) is involved in various cellular and physiological processes such as proliferation, motility, growth and metastasis. Nitric oxide (NO) promotes tumor invasiveness and metastasis by activating various enzymes. Herein, we investigated whether hypoxia-inducible NO regulates Tβ4 expression and cancer cell migration using HeLa cervical cancer cells. NO production and Tβ4 expression were increased in a hypoxic condition. The treatment with N-(β-D-Glucopyranosyl)-N2-acetyl-S-nitroso-D, L-penicillaminamide (SNAP-1), to generate NO, enhanced the transcription of Tβ4 and cancer cell migration. SNAP-1-induced cell migration was decreased by the inhibition of Tβ4 with small interference (si) RNA. In a hypoxic condition, treatment with N(G)-monomethyl-L-arginine (L-NMMA), nitric oxide synthase (NOS) inhibitor, reduced Tβ4 transcriptional activity, and hypoxia-inducible factor (HIF)-1α. Hypoxia-induced cancer cell migration was also decreased by L-NMMA treatment. In a normoxic condition, Tβ4 transcriptional activity was decreased in the cells incubated in the presence of L-NMMA after co-transfection with Tβ4 promoter and GST-conjugated HIF-1α. Collectively, these results suggest that NO could regulate the expression of Tβ4 by direct or indirect effect of HIF-1α on Tβ4 promoter.
authors.affiliation: Department of Bioscience and Biotechnology, Sejong University, Seoul, Korea.
authors.forename: Yun-Kyoung
authors.initials: YK
authors.lastname: Ryu
authors.affiliation: Molecular Imaging Research Center, Korea Institute of Radiological and Medical Science, Seoul, Korea.
authors.forename: Joo-Hyun
authors.initials: JH
authors.lastname: Kang
authors.affiliation: Department of Bioscience and Biotechnology, Sejong University, Seoul, Korea.
authors.forename: Eun-Yi
authors.initials: EY
authors.lastname: Moon
mesh_terms: D000199:Actins / Q000378:metabolism; D002465:Cell Movement / Q000235:genetics; D005786:Gene Expression Regulation / Q000187:drug effects; D006367:HeLa Cells; D006801:Humans; D000860:Hypoxia; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism*; D009569:Nitric Oxide / Q000096:biosynthesis; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D013947:Thymosin / Q000235:genetics* / Q000378:metabolism*; D019323:omega-N-Methylarginine / Q000494:pharmacology; D000099201:Thymosin beta(4)
chemical_list: D000199:Actins; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D034741:RNA, Small Interfering; D013947:Thymosin; D019323:omega-N-Methylarginine; D000099201:Thymosin beta(4)