Faculty of Health Sciences, Department of Medical Physiology, Jagiellonian University School of Medicine, Krakow, Poland.
J Pineal Res. 2010 Oct;49(3):248-55. doi: 10.1111/j.1600-079X.2010.00789.x. Epub 2010 Jul 7.
Pancreatic cancer is a highly lethal disease with a poor prognosis for long-term survival rate at all stages of invasiveness. It responds poorly to radio- and chemotherapy because the tumor cells are resistant to apoptosis. Melatonin has been reported to inhibit pancreatic cancer growth in experimental studies in animals but the effect of melatonin on cultured human pancreatic carcinoma cells has not been tested. Moreover, we have recently shown that melatonin stimulates production of two major anti-apoptotic heat shock proteins, HSP27 and HSP 90, in pancreatic carcinoma cells. This study investigated the changes in intrinsic pathway of apoptosis at the mitochondrial level and cascade of caspases in human pancreatic carcinoma cells (PANC-1) cells subjected to melatonin and/or luzindole. Melatonin (10⁻⁸ -10⁻¹² m), the nonselective melatonin receptor antagonist, luzindole (10⁻⁸ -10⁻¹² m) or a combination of both agents were added to PANC-1 cell cultures. Cells were harvested, and the cytoplasmic proteins were isolated after 24 and 48 hr of incubation and analyzed employing co-immunoprecipitation and western blot. Administration of melatonin to the PANC-1 cells resulted in the stimulation of Bcl-2/Bax and caspase-9 proteins levels. The strongest signal of these pro-apoptotic factors was observed at the low concentration (10⁻¹² m) of melatonin. Pretreatment with luzindole alone and prior to the addition of melatonin reversed the stimulatory effect of this indoloamine on Bcl-2/Bax and caspase-9 proteins expression in PANC-1 cells. This is the first study to demonstrate a pro-apoptotic effect of low (physiological) concentration of melatonin on the pancreatic carcinoma cells. In conclusion, melatonin induced pro-apoptotic pathways in human pancreatic carcinoma, probably by interaction with the Mel-1 A/B receptors.
胰腺癌是一种高度致命的疾病，在所有侵袭阶段的长期生存率预后都很差。由于肿瘤细胞对细胞凋亡有抵抗力，因此对放射和化学疗法的反应不佳。有报道称褪黑素可抑制动物实验中的胰腺癌生长，但褪黑素对培养的人胰腺癌细胞的影响尚未得到测试。此外，我们最近表明，褪黑素可刺激胰腺癌细胞中两种主要的抗细胞凋亡热休克蛋白 HSP27 和 HSP90 的产生。本研究研究了褪黑素和/或 luzindole 处理后人胰腺癌细胞（PANC-1）细胞中线粒体水平凋亡内在途径和 caspase 级联的变化。褪黑素（10⁻⁸ -10⁻¹² m），非选择性褪黑素受体拮抗剂，luzindole（10⁻⁸ -10⁻¹² m）或两者的组合被添加到 PANC-1 细胞培养物中。孵育 24 和 48 小时后收获细胞，并分离细胞质蛋白，并采用共免疫沉淀和蛋白质印迹进行分析。褪黑素处理 PANC-1 细胞导致 Bcl-2/Bax 和 caspase-9 蛋白水平的刺激。在低浓度（10⁻¹² m）的褪黑素下观察到这些促凋亡因子的最强信号。单独用 luzindole 预处理，然后加入褪黑素，可逆转这种吲哚胺对 PANC-1 细胞中 Bcl-2/Bax 和 caspase-9 蛋白表达的刺激作用。这是第一项研究表明低（生理）浓度的褪黑素对胰腺癌细胞具有促凋亡作用。总之，褪黑素诱导了人胰腺癌细胞的促凋亡途径，可能是通过与 Mel-1A/B 受体相互作用。
