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

间变性甲状腺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。寻找有效的策略来抑制未分化癌的生长，延长患者的预后是当务之急。我们重点研究了泛素-蛋白酶体系统。蛋白酶体是一种主要的胞内蛋白酶，由至少14个不同但同源的亚基组成，分子质量在21-32kD之间，它们组装成一个约700 kDa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定位于癌细胞的细胞核中，提示PA28g可能是调控癌细胞生长的良好候选者之一。蛋白酶体抑制剂，如La…CTACYSTIN显著阻断甲状腺癌细胞的DNA合成，提示固有的20S蛋白酶体参与了癌细胞的生长。然后，我们使用大鼠功能甲状腺细胞系FRTL5细胞分析了PA28g的详细翻转。有趣的是，促甲状腺激素和胰岛素治疗不仅上调了PA28-γ的表达，而且还将PA28-γ从胞浆招募到胞核。促甲状腺激素和胰岛素的联合使用对PA28-γ的诱导率最高，对FRTL5DNA的合成具有双重诱导性。因此，我们的结果表明，PA28-γ是由促甲状腺激素和胰岛素在甲状腺细胞中诱导的，并可能通过增强20S蛋白酶体活性而促进甲状腺细胞的生长。综上所述，高表达的蛋白酶体成分如C2或PA28-γ将是调控蛋白酶体活性的良好候选基因，从而干扰间变性癌细胞的生长。同时，我们寻找了新的候选基因来调控间变性甲状腺癌的生长速度。为了分离一个新的基因，我们使用了一种名为SEREX的独特策略。我们利用从癌组织中提取的表达文库，用自体患者血清检测1×106斑块。毕竟，我们可以分离出两个阳性克隆。其中WD重复蛋白1(WD Repeat Protein 1，WDR1)是人类肌动蛋白相互作用蛋白1的同源基因。WDR1在未分化甲状腺癌组织中高表达，提示WDR1可能参与了癌细胞的增殖。目前尚不清楚WDR1蛋白是通过泛素-蛋白酶体依赖途径降解的。但是，如果它通过蛋白酶体依赖的方式被降解，WDR1将是一个很好的抗癌治疗候选药物。较少

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