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

甲状腺未分化癌是一种低分化癌，见于老年人。间变性癌患者预后较差。开发有效的策略来抑制间变性癌的生长并延长患者的预后是一项紧迫的任务。我们专注于泛素蛋白酶体系统。蛋白酶体是一种主要的细胞内蛋白酶，是一种大型蛋白质复合物，由至少 14 个不同但同源的亚基组成，分子量为 21-32kD，它们组装成大约 700kDa 的圆柱形结构。我们分析了甲状腺未变性癌中蛋白酶体亚基的表达，发现蛋白酶体亚基C2和蛋白酶体激活剂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。蛋白酶体抑制剂如 la … More ctacystin 显着阻断了甲状腺癌细胞系的 DNA 合成，表明内在的 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 细胞分析了 PA28g 的详细周转率。有趣的是，TSH 和胰岛素治疗不仅上调 PA28-γ 表达，而且还将 PA28-γ 从细胞质招募到细胞核。 TSH 和胰岛素的组合显示出最高的 PA28-γ 诱导能力以及 FRTL5 的双 DNA 合成能力。因此，我们的结果表明 PA28-γ 是由甲状腺细胞中的致甲状腺肿因子、TSH 和胰岛素诱导的，并且可能通过增强 20S 蛋白酶体活性来促进甲状腺细胞生长。总而言之，过表达的蛋白酶体成分（例如 C2 或 PA28-γ）将成为操纵蛋白酶体活性的良好候选基因，从而干扰未分化癌细胞的生长。同时，我们寻找新的候选基因来绘制未分化甲状腺癌的生长速率。为了分离新基因，我们使用了一种名为 SEREX 的独特策略。我们使用源自癌症组织的表达文库，并通过自体患者血清调查了 1X106 斑块。毕竟，我们可以分离出两个阳性克隆。其中之一是WD重复蛋白1（WDR1），它是肌动蛋白相互作用蛋白1的人类对应物。WDR1在未分化甲状腺癌组织中高表达，表明WDR1可能参与癌细胞增殖。目前尚不清楚 WDR1 蛋白是通过泛素蛋白酶体依赖性途径降解的。但是，如果它通过蛋白酶体依赖性方式降解，WDR1 将成为抗癌治疗的良好候选者。较少的

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