Endocrine Surgery Research Laboratories, Department of Surgery, University of Wisconsin, Madison, Wisconsin 53792, USA.
J Surg Res. 2010 Jan;158(1):15-9. doi: 10.1016/j.jss.2009.05.032.
Carcinoid cancers are the most common neuroendocrine (NE) tumors, and limited treatment options exist. The inhibition of glycogen synthase kinase-3beta (GSK-3beta) has been shown to be a potential therapeutic target for the treatment of carcinoid disease. In this study, we investigate the ability of MG-132, a proteasome inhibitor, to inhibit carcinoid growth, the neuroendocrine phenotype, and its association with GSK-3beta.
Human pulmonary (NCI-H727) and gastrointestinal (BON) carcinoid cells were treated with MG-132 (0-4microM). Cellular growth was measured by the 3-[4,5-dimethylthiazole-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay. Levels of total and phosphorylated GSK-3beta and the NE markers chromogranin A (CgA), Achaete-Scute complex-like 1 (ASCL1), as well as the apoptotic markers poly (ADP-ribose), polymerase (PARP), and cleaved caspase-3 were determined by Western blot.
Treating carcinoid cells with MG-132 resulted in growth inhibition, a dose-dependent inhibition of CgA and ASCL1, as well as an increase in the levels of cleaved PARP and cleaved caspase-3. Additionally, an increase in the level of phosphorylated GSK-3beta was observed.
MG-132 inhibits cellular growth and the neuroendocrine phenotype. This proteasome inhibitor warrants further preclinical investigation as a possible therapeutic strategy for intractable carcinoid disease.
类癌癌是最常见的神经内分泌（NE）肿瘤，治疗选择有限。糖原合酶激酶-3β（GSK-3β）的抑制已被证明是治疗类癌疾病的潜在治疗靶点。在这项研究中，我们研究了蛋白酶体抑制剂 MG-132 抑制类癌生长、神经内分泌表型及其与 GSK-3β 的关联的能力。
用人肺（NCI-H727）和胃肠道（BON）类癌细胞用 MG-132（0-4μM）处理。通过 3-[4,5-二甲基噻唑-2-基]-2,5-二苯基四氮唑溴盐（MTT）测定法测量细胞生长。通过 Western blot 测定总和磷酸化 GSK-3β以及神经内分泌标志物嗜铬粒蛋白 A（CgA）、Achaete-Scute 复合物样 1（ASCL1）以及凋亡标志物多聚（ADP-核糖）聚合酶（PARP）和裂解的 caspase-3 的水平。
用 MG-132 处理类癌细胞导致生长抑制，CgA 和 ASCL1 的剂量依赖性抑制，以及裂解的 PARP 和裂解的 caspase-3 的水平增加。此外，还观察到磷酸化 GSK-3β水平增加。
MG-132 抑制细胞生长和神经内分泌表型。这种蛋白酶体抑制剂值得进一步的临床前研究，作为治疗难治性类癌疾病的潜在治疗策略。
