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Induction of apoptosis and inhibition of angiogenesis by COX-2 inhibitors in hepatocellular carcinomas

COX-2 抑制剂在肝细胞癌中诱导细胞凋亡并抑制血管生成

基本信息

批准号：
11670551
负责人：
KOGA Hironori
金额：
$ 1.41万
依托单位：
Kurume University School of Medicine
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11670551/
关键词：
COX-2 angiogenesis VEGF apoptosis PPAR γ cell cycle p21 p27 pRb NSAID NS398 PGE2 増殖抑制

项目摘要

In this project, we have investigated anti-tumor effect of NS-398, a selective COX-2 inhibitor, on human hepatoma cells, focusing on the agent's ability to induce apoptosis in those cells and the ability to inhibit VEGF production from those cells. Constitutive expression of COX-2 was found by RT-PCR and immunocytochemistry in the hepatoma cells examined. A significant growth-inhibitory effect was demonstrated in NS-398-treated hepatoma cells, however, the effect was not attributable to an increase in apoptotic cells nor to inactivation of COX-2 by NS-398, suggesting involvement of a COX-2-independent mechanism in growth inhibition of hepatoma cells treated with COX-2 inhibitors. While the study was going on, NS-398 has been reported to be not only a COX-2 inhibitor but also a PPAR γ ligand (J Biol Chem, 1999). This finding encouraged us to perform subsequent studies to elucidate the involvement of PPAR γ in growth inhibition in hepatoma cells. PPAR γ was constitutively expressed in all the cell lines (HLF, HuH-7, HAK- 1A, HAK-1B, and HAK-5) and the HCC tissues used in this study. A cytostatic effect of PPAR γ ligands was found in those cell lines, and this inhibition of cell growth was dosage-dependent. G1 arrest was apparently demonstrated in flow cytometric analysis in HLF, HAK-1A, HAK-1B, and HAK-5, all of which showed an increased expression of p21.However, HuH-7, lacking p21 protein expression, did not demonstrate clear arrest in the cell cycle analysis. HLF, which was pRb-deficient, responded most profoundly to a PPAR γ ligand, showing an increased expression in not only p21 but also in p27 and p18. These findings suggested that p21, p27, and p18 might be involved in PPAR γ ligand-induced cell cycle arrest.

在这个项目中，我们研究了选择性COX-2抑制剂NS-398对人肝癌细胞的抗肿瘤作用，重点研究了该药物诱导肝癌细胞凋亡的能力和抑制肝癌细胞产生VEGF的能力。RT-PCR和免疫细胞化学检测发现COX-2在肝癌细胞中组成性表达。NS-398对肝癌细胞有显著的生长抑制作用，然而，这种作用不是由于凋亡细胞的增加，也不是由于NS-398对COX-2的失活，这表明COX-2抑制剂对肝癌细胞的生长抑制涉及COX-2独立的机制。在研究进行期间，NS-398被报道不仅是COX-2抑制剂，而且是PPAR γ配体（J Biol Chem, 1999）。这一发现鼓励我们进行后续研究，以阐明PPAR γ在肝癌细胞生长抑制中的作用。PPAR γ在所有细胞系（HLF、HuH-7、HAK- 1A、HAK- 1b和HAK-5）和本研究中使用的HCC组织中均有组成性表达。在这些细胞系中发现PPAR γ配体的细胞抑制作用，并且这种抑制作用是剂量依赖性的。流式细胞术分析显示，在HLF、HAK-1A、HAK-1B和HAK-5中，G1阻滞明显，均显示p21的表达增加。然而，缺乏p21蛋白表达的HuH-7在细胞周期分析中没有表现出明显的阻滞。prb缺失的HLF对PPAR γ配体的反应最为深刻，不仅在p21中表达增加，而且在p27和p18中表达增加。这些发现提示p21、p27和p18可能参与PPAR γ配体诱导的细胞周期阻滞。