Functional role of STRAP in colorectal cancer metastasis and in chemoresistance

项目摘要/摘要 尽管结直肠癌(CRC)治疗后的复发率很高，而且相对较快 肿瘤干细胞在实体瘤中的研究进展，由于对肿瘤干细胞的认识有限，阻碍了研究 结直肠癌上皮干细胞的层次性和疾病的复杂性异质性。最近的证据表明 结直肠肿瘤由种植肿瘤的一小部分癌症干细胞组成，可能是 导致转移、抗拒治疗和肿瘤复发。其他人(Buess等人，2004)和我们 (Halder等人，2006)已经证明了STRAP(丝氨酸苏氨酸激酶受体相关蛋白)是 结直肠癌中显著上调，包括转移和结直肠癌中的STAPP上调 患者的化疗导致了较差的存活率，这表明它可能对 侵袭性疾病和化疗耐药性。因此，理解STRAP在CRC中的功能作用 转移，在维持肿瘤干细胞样细胞，以及在化疗耐药方面是非常关键的。 我们鉴定了一种新的含有WD结构域的蛋白，称为STRAP，它与两种转化生长因子结合 受体复合体和Smad7，并抑制转化生长因子-β信号转导。我们已经证明皮带是向上调节的 几种癌症，诱导上皮向间充质(EMT)转变(Kashikar等人，2010)，并促进细胞 以非转化生长因子依赖的方式在体外生长和致瘤性(Halder等人，2006年)。我们的初步数据 提示STRAP调控MMPs的表达，并调节Wnt/？-catenin和Notch信号转导。要确定 在活体中的作用，我们最近产生了带状基因敲除的小鼠，它在9.5岁时是胚胎致命的 DPC。偶氮甲烷治疗带状杂合小鼠在以下情况下产生更少和更小的肿瘤 与野生型小鼠比较。为了研究皮带在特定器官中的作用，我们还 使用Cre-lox方法产生条件性基因敲除小鼠。因此，对转化生长因子的了解很少。 STAPP在肠癌转移和化疗耐药中的独立作用。基于背景 根据我们的信息和我们的初步结果，我们提出了以下假设： 在结直肠癌转移中发挥积极作用，并与Wnt/？catenin和Wnt？ Notch通路参与了结肠癌干细胞的自我更新和化疗耐药。以下是 提出了检验这些假说的具体目标：目标1：确定捆绑的机制 会导致结直肠癌的转移。目标2：确定背带在维护和自我保护中的作用 结肠癌干细胞的更新。目的3：确定STRAP在调节化疗耐药中的作用 结直肠癌。 影响：尽管治疗方案有所发展，但转移仍然是最关键的 生存的决定因素，因为转移性结直肠癌患者的中位生存期为5个月 退伍军人。此外，抗药性和癌症复发是影响生存的另外两个关键因素。 CRC的影响因素。拟议目标的完成将揭示启联咨询服务中心的新功能。 转移、干细胞自我更新和耐药。该项目的成果将提供强有力的 通过针对这种非靶向侵袭性疾病的靶向皮带来开发治疗方法的翻译潜力。 这项基础和临床前生物医学研究将包括两个优先研究领域 与吸烟和妇女健康有关的危险行为(RFA#BX-16-001)。

Project Summary/Abstract Despite the high rate of recurrence following therapy in colorectal cancer (CRC) and relatively rapid pace of cancer stem-like cell research in solid tumors, researches are impeded due to limited knowledge of the CRC epithelial stem cell hierarchy and complex heterogeneity of the disease. Recent evidences suggest that colorectal tumors comprise a small fraction of cancer stem-like cells that seed the tumor bulk and may be responsible for metastasis, resistance to therapy, and tumor recurrence. Others (Buess et al., 2004) and we (Halder et al, 2006) have shown that STRAP (Serine Threonine Kinase Receptor Associated Protein) is significantly upregulated in colorectal carcinomas including metastases, and upregulation of STRAP in CRC patients contributes to worse survival with chemotherapy, suggesting its potential contribution to the aggressive disease and chemoresistance. Therefore, understanding the functional role of STRAP in CRC metastasis, in the maintenance of cancer stem-like cells, and in chemoresistance is very crucial. We identified the novel WD-domain containing protein called STRAP that binds with both TGF-ß receptor complex and Smad7, and inhibits TGF-ß signaling. We have shown that STRAP is upregulated in several cancers, induces epithelial-to-mesenchymal (EMT) transition (Kashikar et al, 2010), and promotes cell growth and tumorigenicity in vitro in a TGF-ß-independent manner (Halder et al, 2006). Our preliminary data suggest that STRAP regulates the expression of MMPs, and Wnt/ß-catenin and Notch signaling. To determine the role of STRAP in vivo, we have recently generated Strap knock out mice, which is embryonic lethal at 9.5 dpc. Azoxymethane treatment of the Strap heterozygous mice produces fewer and smaller tumors when compared with wild type mice. To study the effect of STRAP in an organ specific manner, we have also generated conditional knock out mice using the Cre-lox approach. Therefore, little is known about the TGF-ß- independent role of STRAP in intestinal cancer metastasis and chemoresistance. Based on the background information and our preliminary results, we have formulated the following hypotheses: Upregulation of STRAP in colorectal cancer plays an active role in metastasis and its functional interaction with Wnt/ß-catenin and Notch pathway is involved in colon cancer stem-like cell self-renewal and chemoresistance. The following Specific Aims are proposed to test these hypotheses: Aim 1: Determine the mechanism of how STRAP contributes to colorectal cancer metastasis. Aim 2: Determine the role of STRAP in the maintenance and self- renewal of colon cancer stem-like cells. Aim 3: Determine the role of STRAP in regulating chemoresistance of colorectal cancer. Impact: Despite the development of treatment regimens, metastasis remains the most critical determinant of survival, as median survival for patients with metastatic colorectal cancer is 5 months among veterans. Moreover, drug resistance and relapse of cancers are the other two critical survival-influencing factors of CRC. Completion of the proposed aims will uncover the novel function of STRAP in CRC metastasis, stem-like cell self-renewal, and drug resistance. The outcome of this project will provide strong translational potential to develop therapeutics by targeting STRAP for this un-targetable aggressive disease. This basic and preclinical biomedical research will include two priority research areas of specific interest to BLR&D, risky behavior related to smoking and women's health (RFA# BX-16-001).