过表达bcl-2的前列腺癌细胞的血管生成潜力。

Angiogenic potential of prostate carcinoma cells overexpressing bcl-2.

作者信息

Fernandez A, Udagawa T, Schwesinger C, Beecken W, Achilles-Gerte E, McDonnell T, D'Amato R

机构信息

Department of Surgery, Division of Surgical Research, Children's Hospital, Boston, MA 02115, USA.

出版信息

J Natl Cancer Inst. 2001 Feb 7;93(3):208-13. doi: 10.1093/jnci/93.3.208.

DOI:10.1093/jnci/93.3.208

PMID:11158189

Abstract

BACKGROUND

Tumors commonly outgrow their blood supply, thereby creating hypoxic conditions, which induce apoptosis and increase expression of angiogenic growth factors. The bcl-2 oncogene inhibits apoptosis induced by a variety of stimuli, including hypoxia. On the basis of bcl-2's role in regulating apoptosis in response to hypoxia, we hypothesized that this oncogene might affect other responses to hypoxia, such as the expression of angiogenic growth factors.

METHODS

Three prostate carcinoma cell lines, PC3, LNCaP, and DU-145, were stably transfected with a bcl-2 complementary DNA (cDNA), and transfectants were analyzed in vitro for the expression of angiogenic factors after exposure to either normoxic (19% O(2)) or hypoxic (1% O(2)) conditions. The in vivo angiogenic potential of the transfected cells was determined by analyzing vessel density in xenografts derived from them and by measuring the ability of these xenografts to induce neovascularization when implanted in mouse corneal micropockets. Statistical tests were two-sided.

RESULTS

When exposed to hypoxic conditions, prostate carcinoma cells overexpressing bcl-2 expressed statistically significantly higher levels of vascular endothelial growth factor (VEGF), an angiogenic factor, than control-transfected cells (P = .001 for PC3, P = .04 for DU-145 after 48 hours). This effect of bcl-2 was independent of its antiapoptotic activity because increased expression of VEGF was detected in PC3 cells overexpressing bcl-2 even though PC3 cells are inherently resistant to hypoxia-induced apoptosis. In vivo, xenograft tumors derived from the bcl-2-overexpressing prostate carcinoma cell lines displayed increased angiogenic potential and grew more aggressively than tumors derived from the control cell lines (P =.03 for PC3). Treatment of bcl-2-overexpressing and control tumors with the antiangiogenic drug TNP-470 neutralized the aggressive angiogenesis in bcl-2-overexpressing tumors (P = .04 for PC3, P = .004 for DU-145) and the moderate angiogenesis in control tumors (P = .01 for PC3, P = .05 for DU-145), resulting in similar growth rates for both tumors.

CONCLUSIONS

bcl-2 may play a dual role in tumorigenesis by suppressing apoptosis and by stimulating angiogenesis.

摘要

背景

肿瘤通常生长超过其血液供应，从而产生缺氧条件，这会诱导细胞凋亡并增加血管生成生长因子的表达。bcl-2癌基因可抑制包括缺氧在内的多种刺激所诱导的细胞凋亡。基于bcl-2在调节缺氧反应中的细胞凋亡作用，我们推测该癌基因可能会影响对缺氧的其他反应，如血管生成生长因子的表达。

方法

用bcl-2互补DNA（cDNA）稳定转染三种前列腺癌细胞系PC3、LNCaP和DU-145，在体外分析转染细胞在常氧（19% O₂）或缺氧（1% O₂）条件下血管生成因子的表达。通过分析源自这些细胞的异种移植瘤中的血管密度，以及测量这些异种移植瘤植入小鼠角膜微袋时诱导新生血管形成的能力，来确定转染细胞的体内血管生成潜力。统计检验采用双侧检验。

结果

暴露于缺氧条件时，过表达bcl-2的前列腺癌细胞表达血管生成因子血管内皮生长因子（VEGF）的水平在统计学上显著高于对照转染细胞（PC3为P = 0.001，DU-145在48小时后为P = 0.04）。bcl-2的这种作用与其抗凋亡活性无关，因为在过表达bcl-2的PC3细胞中检测到VEGF表达增加，尽管PC3细胞本身对缺氧诱导的细胞凋亡具有抗性。在体内，源自过表达bcl-2的前列腺癌细胞系的异种移植瘤显示出更高的血管生成潜力，并且比源自对照细胞系的肿瘤生长更具侵袭性（PC3为P = 0.03）。用抗血管生成药物TNP-470处理过表达bcl-2的肿瘤和对照肿瘤，可中和过表达bcl-2的肿瘤中的侵袭性血管生成（PC3为P = 0.04，DU-145为P = 0.004）以及对照肿瘤中的中度血管生成（PC3为P = 0.01，DU-145为P = 0.05），导致两种肿瘤的生长速率相似。