Okuda Yorihide, Nakamura Hideji, Yoshida Kenya, Enomoto Hirayuki, Uyama Hirokazu, Hirotani Tomonori, Funamoto Masanobu, Ito Hiroaki, Everett Allen D, Hada Toshikazu, Kawase Ichiro
Department of Molecular Medicine, Osaka University Graduate School of Medicine, 2-2 Yamada-oka, Suita, Osaka 565-0871.
Cancer Sci. 2003 Dec;94(12):1034-41. doi: 10.1111/j.1349-7006.2003.tb01397.x.
Hepatoma-derived growth factor (HDGF) is highly expressed in tumor cells, and stimulates their proliferation. In the present study, we investigated the role of HDGF in tumorigenesis and elucidated the mechanism of action. Stable transfectants of NIH3T3 cells overexpressing HDGF did not show significant anchorage-independent growth in soft agar assay. However, these stable transfectants overexpressing HDGF generated sarcomatous tumors in nude mice. These tumors were red-colored macroscopically, and histologically showed a rich vascularity. Immunohistochemical analysis using CD31 antibody showed new vessel formation. Recombinant HDGF stimulated proliferation of human umbilical vein endothelial cells in a dose-dependent manner, and stimulated tubule formation. Furthermore, vascular endothelial growth factor (VEGF) was detected immunohistochemically in the tumor tissues. Transient expression of HDGF induced both VEGF gene and protein expression as demonstrated by a reporter assay using VEGF gene promoter. The administration of anti-VEGF neutralizing antibody significantly suppressed, but did not block, the tumor growth of HDGF-overexpressing cells in nude mice. Thus, these findings suggested that HDGF-induced tumor formation in vivo involves induction of VEGF as well as direct angiogenic activity.
肝癌衍生生长因子（HDGF）在肿瘤细胞中高表达，并刺激其增殖。在本研究中，我们研究了HDGF在肿瘤发生中的作用，并阐明了其作用机制。在软琼脂试验中，过表达HDGF的NIH3T3细胞稳定转染子未显示出明显的非锚定依赖性生长。然而，这些过表达HDGF的稳定转染子在裸鼠中产生了肉瘤样肿瘤。这些肿瘤在宏观上呈红色，组织学上显示血管丰富。使用CD31抗体的免疫组织化学分析显示有新血管形成。重组HDGF以剂量依赖性方式刺激人脐静脉内皮细胞增殖，并刺激小管形成。此外，在肿瘤组织中通过免疫组织化学检测到血管内皮生长因子（VEGF）。如使用VEGF基因启动子的报告基因试验所示，HDGF的瞬时表达诱导了VEGF基因和蛋白表达。抗VEGF中和抗体的给药显著抑制但未阻断裸鼠中过表达HDGF细胞的肿瘤生长。因此，这些发现表明HDGF在体内诱导肿瘤形成涉及VEGF的诱导以及直接的血管生成活性。
