The Development of novel anticancer drugs for anaplastic thyroid carcinoma by collaboration of medicine and engineering

甲状腺间变性癌是一种在老年人中发现的低分化癌。间变性癌患者预后较差。寻找抑制间变性癌生长、延长患者预后的有效策略是一项迫切需要解决的问题。我们主要研究泛素-蛋白酶体系统。蛋白酶体是一种主要的细胞内蛋白酶，是由至少14个不同但同源的亚基组成的大型蛋白质复合物，分子质量为21-32kD，它们组装成约700kDa的圆柱形结构。我们分析了蛋白酶体亚基在间变性甲状腺癌中的表达，发现蛋白酶体亚基C2和蛋白酶体激活物g（PA28g）在其快速生长的癌细胞中高表达。有趣的是，PA28g位于癌细胞的细胞核中，这表明PA28g可能是操纵癌细胞生长的良好候选者之一。la…More ctacystin等蛋白酶体抑制剂显著阻断甲状腺癌细胞DNA合成，表明其内在的20S蛋白酶体参与了癌细胞的生长。然后，我们使用大鼠功能性甲状腺细胞系FRTL5细胞分析PA28g的详细翻转。有趣的是，TSH和胰岛素治疗不仅上调了PA28-γ的表达，而且还将PA28-γ从细胞质募集到细胞核。TSH和胰岛素联合使用对PA28-γ和FRTL5双DNA合成的诱导作用最强。因此，我们的研究结果表明，甲状腺细胞中的PA28-γ是由甲状腺激素、TSH和胰岛素诱导的，并可能通过增强20S蛋白酶体活性来促进甲状腺细胞的生长。综上所述，过度表达的蛋白酶体成分，如C2或PA28-γ，将是操纵蛋白酶体活性的良好候选，从而干扰间变性癌细胞的生长。同时，我们寻找新的调控间变性甲状腺癌生长速率的候选基因。为了分离新基因，我们使用了一种名为SEREX的独特策略。我们使用来自肿瘤组织的表达文库，通过患者自身血清检测1X106斑块。毕竟，我们可以分离出两个阳性克隆。其中一个是WD重复蛋白1(WDR1)，它是肌动蛋白相互作用蛋白1的人类对偶物。WDR1在间变性甲状腺癌组织中高表达，提示WDR1可能参与癌细胞增殖。目前尚不清楚WDR1蛋白是否通过泛素-蛋白酶体依赖途径降解。但是，如果它通过蛋白酶体依赖的方式被降解，WDR1将成为抗癌治疗的良好候选者。少

Anaplastic thyroid carcinoma is a poorly differentiated carcinoma found in elderly people. The patients with anaplastic carcinoma always suffer from poor prognosis. It is an urgent business to develop the effective strategy to suppress the growth of anaplastic carcinoma and prolong the prognosis of patients. We focused on the ubiquitin-proteasome sytem. Proteasome is a major intracellular proteinase found as a large protein complex composed of at least 14 distinct but homologous subunits with molecular masses of 21-32kD and they are assembled into an approximately 700kDa cylindcal structure. We analyzed the expression of proteasome subunits in anaplastic thyroid carcinoma and found that proteasome subunit C2 and proteasome activator g(PA28g) are highly expressed in its rapid-growing cancer cells. Interestinglly, PA28g is localized in nuclei of cancer cells, suggesting PA28g, could be one of the good candidate for manipulating the growth of cancer cells. Proteasome inhibitors such as la … More ctacystin significantly blocked the DNA synthesis of thyroid carcinoma cell line, indicating the intrinsic 20S proteasome is involved in cancer cell growth. We then analyzed the detailed turn-over of PA28g using rat functional thyroid cell line, FRTL5 cells. Interestingly, TSH and insulin treatment not only upregulate PA28-γ expression but also recruite PA28-γ from cytosol to nucleus. The combination of TSH and insulin showed highest inducibility of PA28-γ as well as dual DNA synthesis of FRTL5. Thus, our results indicate PA28-γ is induced by goitrogenic factors, TSH and insulin, in thyroid cell and potentially contribute to thyroid cell growth by potentiating 20S proteasome activity. Taken together, overexpressed proteasome component such as C2 or PA28-γ will be good candidates for manipulating proteasome activity, thereby interfering with anaplastic cancer cell growth.Simultaneously, we searched novel candidate genes for mapipulating the growth rate of anaplastic thyroid cancer. In order to isolate a novel gene, we used a unique strategy named SEREX. We used expression library derived from cancer tissue and surveyed 1X106 plaque by autologous patient sera. After all, we could isolate two positive clones. One of them was WD repeat protein 1(WDR1), which is the human counterpart of actin interacting protein 1. WDR1 is highly expressed in anaplastic thyroid cancer tissues, indicating that WDR1 could be involved in cancer cell proliferation. It still remains unclear that WDR1 protein is degraded by ubiquitin-proteasome dependent pathway. But, if it is degraded via proteasome-dependent fashion, WDR1 will be a good candidate for anti-cancer therapy. Less