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論文 |
論文
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Du, Wa ; Takuwa, Noriko ; Yoshioka, Kazuaki ; Okamoto, Yasuo ; Gonda, Koichi ; Sugihara, Kazushi ; Fukamizu, Akiyoshi ; Asano, Masahide ; Takuwa, Yoh
概要:
金沢大学医薬保健研究域医学系<br />Sphingosine-1-phosphate (S1P) has been implicated in tumor angiogenesis by acting through the Gi-cou
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pled chemotactic receptor S1P1. Here, we report that the distinct receptor S1P2 is responsible for mediating the G12/13/Rho-dependent inhibitory effects of S1P on Akt, Rac, and cell migration, thereby negatively regulating tumor angiogenesis and tumor growth. By using S1P2LacZ/+ mice, we found that S1P2 was expressed in both tumor and normal blood vessels in many organs, in both endothelial cells (EC) and vascular smooth muscle cells, as well as in tumor-associated, CD11b-positive bone marrow-derived cells (BMDC). Lewis lung carcinoma or B16 melanoma cells implanted in S1P2-deficient (S1P2-/-) mice displayed accelerated tumor growth and angiogenesis with enhanced association of vascular smooth muscle cells and pericytes. S1P2-/- ECs exhibited enhanced Rac activity, Akt phosphorylation, cell migration, proliferation, and tube formation in vitro. Coinjection of S1P2-/- ECs and tumor cells into wild-type mice also produced a relative enhancement of tumor growth and angiogenesis in vivo. S1P2-/- mice were also more efficient at recruiting CD11b-positive BMDCs into tumors compared with wild-type siblings. Bone marrow chimera experiments revealed that S1P2 acted in BMDCs to promote tumor growth and angiogenesis. Our results indicate that, in contrast to endothelial S1P1, which stimulates tumor angiogenesis, S1P 2 on ECs and BMDCs mediates a potent inhibition of tumor angiogenesis, suggesting a novel therapeutic tactic for anticancer treatment. ©2010 AACR.
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論文 |
論文
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Wang, Fei ; Okamoto, Yasuo ; Inoki, Isao ; Yoshioka, Kazuaki ; Du, Wa ; Qi, Xun ; Takuwa, Noriko ; Gonda, Koichi ; Yamamoto, Yasuhiko ; Ohkawa, Ryunosuke ; Nishiuchi, Takumi ; Sugimoto, Naotoshi ; Yatomi, Yutaka ; Mitsumori, Kunitoshi ; Asano, Masahide ; Kinoshita, Makoto ; Takuwa, Yoh
概要:
金沢大学医薬保健研究域医学系<br />Sphingosine-1-phosphate (S1P) is a biologically active sphingolipid that has pleiotropic effects in
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a variety of cell types including ECs, SMCs, and macrophages, all of which are central to the development of atherosclerosis. It may therefore exert stimulatory and inhibitory effects on atherosclerosis. Here, we investigated the role of the S1P receptor S1PR2 in atherosclerosis by analyzing S1pr2–/– mice with an Apoe–/– background. S1PR2 was expressed in macrophages, ECs, and SMCs in atherosclerotic aortas. In S1pr2–/–Apoe–/– mice fed a high-cholesterol diet for 4 months, the area of the atherosclerotic plaque was markedly decreased, with reduced macrophage density, increased SMC density, increased eNOS phosphorylation, and downregulation of proinflammatory cytokines compared with S1pr2+/+Apoe–/– mice. Bone marrow chimera experiments indicated a major role for macrophage S1PR2 in atherogenesis. S1pr2–/–Apoe–/– macrophages showed diminished Rho/Rho kinase/NF-κB (ROCK/NF-κB) activity. Consequently, they also displayed reduced cytokine expression, reduced oxidized LDL uptake, and stimulated cholesterol efflux associated with decreased scavenger receptor expression and increased cholesterol efflux transporter expression. S1pr2–/–Apoe–/– ECs also showed reduced ROCK and NF-κB activities, with decreased MCP-1 expression and elevated eNOS phosphorylation. Pharmacologic S1PR2 blockade in S1pr2+/+Apoe–/– mice diminished the atherosclerotic plaque area in aortas and modified LDL accumulation in macrophages. We conclude therefore that S1PR2 plays a critical role in atherogenesis and may serve as a novel therapeutic target for atherosclerosis.
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