Infiltration of COX-2–expressing macrophages is a prerequisite for IL-1β–induced neovascularization and tumor growth
Shintaro Nakao, … , Michihiko Kuwano, Mayumi Ono
Shintaro Nakao, … , Michihiko Kuwano, Mayumi Ono
Published November 1, 2005
Citation Information: J Clin Invest. 2005;115(11):2979-2991. https://doi.org/10.1172/JCI23298.
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Research Article Angiogenesis

Infiltration of COX-2–expressing macrophages is a prerequisite for IL-1β–induced neovascularization and tumor growth

Abstract

Inflammatory angiogenesis is a critical process in tumor progression and other diseases. The inflammatory cytokine IL-1β promotes angiogenesis, tumor growth, and metastasis, but its mechanisms remain unclear. We examined the association between IL-1β–induced angiogenesis and cell inflammation. IL-1β induced neovascularization in the mouse cornea at rates comparable to those of VEGF. Neutrophil infiltration occurred on day 2. Macrophage infiltration occurred on days 4 and 6. The anti–Gr-1 Ab-induced depletion of infiltrating neutrophils did not affect IL-1β– or VEGF-induced angiogenesis. The former was reduced in monocyte chemoattractant protein-1–deficient (MCP-1–/–) mice compared with wild-type mice. After day 4, clodronate liposomes, which kill macrophages, reduced IL-1β–induced angiogenesis and partially inhibited VEGF-induced angiogenesis. Infiltrating macrophages near the IL-1β–induced neovasculature were COX-2 positive. Lewis lung carcinoma cells expressing IL-1β (LLC/IL-1β) developed neovasculature with macrophage infiltration and enhanced tumor growth in wild-type but not MCP-1–/– mice. A COX-2 inhibitor reduced tumor growth, angiogenesis, and macrophage infiltration in LLC/IL-1β. Thus, macrophage involvement might be a prerequisite for IL-1β–induced neovascularization and tumor progression.

Authors

Shintaro Nakao, Takashi Kuwano, Chikako Tsutsumi-Miyahara, Shu-ichi Ueda, Yusuke N. Kimura, Shinjiro Hamano, Koh-hei Sonoda, Yasuo Saijo, Toshihiro Nukiwa, Robert M. Strieter, Tatsuro Ishibashi, Michihiko Kuwano, Mayumi Ono

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Figure 1

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IL-1β– and VEGF-induced angiogenesis and inflammatory cell infiltration ...
IL-1β– and VEGF-induced angiogenesis and inflammatory cell infiltration in mouse corneas. (A) Neovascularization 6 days after implanting Hydron pellets containing human or mouse IL-1β or mouse VEGF at the doses shown into male BALB/c mouse corneas. hIL-1β, human IL-1β; mIL-1β, mouse IL-1β; mVEGF, mouse VEGF. (B) Corneal neovascularization induced by human IL-1β (30 ng) or mouse VEGF (200 ng) at the indicated time points. (C) Quantitative analysis of neovascularization on days 4 (white bars) and 6 (black bars). Areas are expressed in mm2. Bars show the mean ± SD of independent experiments (n = 6 or 7). (D) Corneas implanted with IL-1β or VEGF stained by H&E at the indicated time points. (E) Corneal sections on days 2 or 6 after IL-1β–pellet implantation, labeled immunohistochemically (brown) for Gr-1, which was detected in infiltrating cells on days 2 and 6, and F4/80, which was detected on day 6. (F) FACS analysis of infiltrating cells from IL-1β– or VEGF-implanted corneas (n = 5) at the indicated times. Cells were stained with PE-CD11b mAb and FITC–Gr-1 or FITC-F4/80 mAb. The percentages of infiltrating CD11b+Gr-1+ cells in IL-1β–implanted corneas were 53.5% ± 10.4% (day 2), 15.8% ± 4.9% (day 4), and 3.15% ± 0.27% (day 6). The percentages of infiltrating CD11b+Gr-1+ cells in VEGF-implanted corneas were 2.99% ± 1.37% (day 2), 1.95% ± 0.75% (day 4), and 1.08% ± 0.74% (day 6). The percentages of infiltrating CD11b+F4/80+ cells in IL-1β–implanted corneas were 1.85% ± 1.28% (day 2), 5.56% ± 1.61% (day 4), and 5.52% ± 1.14% (day 6). The percentages of infiltrating CD11b+F4/80+ cells in VEGF-implanted corneas were 0.81% ± 0.47% (day 2), 1.30% ± 1.03% (day 4), and 1.90% ± 0.98% (day 6).