胍丁胺抗肿瘤作用的药效学评价与机制探讨

【作者】 王纪防；

【导师】 李锦； 苏瑞斌；

【作者基本信息】 中国人民解放军军事医学科学院 ， 药理学， 2004， 硕士

【摘要】 胍丁胺(agmatine)是左旋精氨酸脱羧基的产物。目前，大多数学者认为它是一种新的神经递质和／或神经调质，是咪唑啉受体的内源性配体。国内外研究已证实胍丁胺具有多种生物学功能，主要包括神经元保护、影响激素或递质的释放、降低血糖浓度、促进肾脏水钠排泄、减少心肌细胞坏死、抑制血管内皮细胞过度增生、刺激胃酸分泌、抗炎、抗抑郁、调节阿片功能等等。作为经典多胺的类似物，胍丁胺对细胞增殖、分化的作用已引起了我们对其抗肿瘤研究的兴趣。本研究旨在整体和体外培养两种实验模型上观察胍丁胺对肿瘤组织和肿瘤细胞增殖的抑制作用，探讨胍丁胺可能的抗肿瘤作用机制，为深入研究胍丁胺的抗肿瘤作用提供药效学依据。皿丁胺抗肿瘤作用的药效学评价与机制探讨中文摘要 二、肌丁胺抗肿瘤作用的机制研究 1、咪哇琳受体拮抗剂咪哇克生本身不影响体外培养MCF细胞的增殖，亦不能阻断肌丁胺抑制MCF细胞增殖，提示在本实验模型上肌丁胺抑制MCF细胞的增殖并非通过激活咪哇琳受体实现的。 2、肌丁胺(1一looopM)对MCF细胞培养介质中的乳酸脱氢酶活性没有显著影响，1000 pM浓度以下的肌丁胺对ovca、Kse:和Kat。一111细胞无抑制增殖作用，提示肌丁胺无细胞毒作用，在本实验模型上肌丁胺抑制MCF细胞的增殖与细胞毒性无关。 3、在生物体内的多胺包括腐胺、精胺和亚精胺。在0.01一1000 pM浓度范围内腐胺对MCF细胞增殖无影响，腐胺(12.5一loop玛能浓度依赖性地拮抗l000pM肌丁胺对体外培养MCF细胞增殖抑制作用。在0.01一1 pM浓度范围内，精胺和亚精胺对MCF细胞增殖无影响，但其浓度达到1一1 00 pM时则具有明确的抑制MCF细胞增殖的作用，且在此浓度范围内与肌丁胺合用能增强肌丁胺抑制肿瘤细胞增殖的作用。这些实验结果提示肌丁胺的抗肿瘤作用可能与其抑制多胺合成有关。 三、结论: 1.肌丁胺有明确的抑制肿瘤细胞增殖的作用，且其抑制肿瘤细胞增殖的作用 具有瘤细胞株特异性。 2.肌丁胺抑制肿瘤增殖的作用与激活咪哇琳受体和细胞毒作用无关。 3.肌丁胺抑制体外培养MCF细胞增殖的作用与其影响多胺合成有关。更多还原

【Abstract】 Agmatine, the analog of polyamine, which was formed by the decarboxylation of L-Arginine by the enzyme L-arginine decarboxylase, has been postulated to be an endogenous ligand for imidazoline receptors (I-R). Many biological functions of agmatine have been found such as neuron protection, influence on the release of hormones and neurotransmitters, antidepression and modulation on opioid functions. The recent discovery for the effect of agmatine on cell proliferation and differentiation has caused our interest in the effects of agmatine on tumor. However, there is no report about whether agmatine can inhibit the proliferation of tumor by now. In this experiment, we have studied the inhibitory effect of agmatine on the proliferation of tumor tissues in mice in vivo and tumor cells in culture in vitro for the first times. In addition, the possible mechanisms for the anti-proliferative effect of agmatine were studied at the same time.Section A: Pharmacological effects of agmatine on tumor cell lines in vitro1 A weak inhibitory effect of agmatine was found on the proliferation of ovaries cancer cell line (Ovca), gastric carcinoma cell line ( K562 ) and human erythroleukemia cell line (Kato-III) in the current experiments. However, in MCF cell line, agmatine inhibited the proliferation of the tumor cells in MTT assay and 3H-thymidine incorporation assay. These results inferred that agmatine had anti-proliferative effect on tumor cells, but this effect was specific for cell lines. Agmatine could inhibit the proliferation of MCF cell in the range of 1~1000u M in a concentration-dependent manner both in the MTT assay and 3H-thymidine incorporation test. The highest inhibitory rate was over 50%. The anti-proliferative effect of agmatine 1000 u M on MCF cell lines exhibited a time-dependent characteristic during 48 hours.2 In mice transplanted with S180 sarcoma and B16 melanoma tumor cell lines, the tumor weight was significantly reduced after the mice were treated with agmatine 5-40 mg.kg-1, and these efFects exhibited a dose-dependent manner.Section B: Possible mechanisms for the antiproliferation of agmatine on tumor cells1 Idazoxan, an antagonist of I-R, had no influence on the proliferation of MCF cellitself and had no action on the inhibitory effects of agmatine on the proliferation of MCF cells. This result indicated that the inhibitory effect of agmatine didn’t due to the activation of I-R.2 As to MCF cells, agmatine (1-1000 u M) had no influence on the activity of LDH, which suggest that agmatine has no direct cell toxicity in vitro and the inhibitory effect of agmatine on the proliferation of MCF cells had nothing to do with the cell toxicity.3 Polyamines include putrescine, spermidine and spermine. Putrescine at the concentration of 0.01-1000 u M, had no inhibitory and facilitory effects on the MCF proliferation. When co-administrated with agmatine, putrescine (12.5-100 u M) reversed agmatine’s inhibitory effect on MCF. Spermine and spermidine, at the concentration of 0.01-1 u M, had no inhibitory and facilitory effect on the proliferation of tumor cells. However, at the concentration of 1-100 u M, spermidine and spermine significantly inhibited the proliferation of tumor cells and enhanced the anti-proliferative effect of agmatine. These results implicated that agmatine had anti-proliferative effect on tumor cells and the possible mechanism might relate to interfere with the synthesis of polyamines.Section C: Conclusion1 Agmatine inhibited the proliferation of tumor cells, and this effect was specific fortumor cell lines.2 The anti-proliferative effect of agmatine on tumor cells didn’t due to the activation of I-R and its cell toxicity.3 The possible mechanism for the anti-proliferative effect of agmatine on MCF cells might be relate to its influence on the synthesis of polyamines.更多还原