Role of Type III TGF-beta Receptor Shedding in Lung Cancer Initiation and Progression

 描述(申请人提供)：转化生长因子(转化生长因子)参与癌症生物学的许多方面，包括增殖、凋亡、迁移和转移。转化生长因子受体的S效应是通过一系列细胞表面受体介导的，其中包括介导下游信号传导的III型转化生长因子受体(TüRIII)。在包括非小细胞肺癌(NSCLC)在内的许多人类癌症中，T？RIII基因缺失，这种缺失与更具侵袭性的疾病和疾病进展有关。T？RIII也经历胞外结构域的切割，产生一种可溶蛋白(ST？RIII)，它可以将配体从细胞表面受体上隔离出来，并阻止转化生长因子-β信号的激活。我们已经证明，通过TüRIII(M740A)的单个碱基对突变而产生的T？RIII脱落的丢失，增加了转化生长因子-β信号转导，并抑制了体内的肿瘤形成和转移。然而，T？RIII的脱落机制以及ST？RIII与细胞表面T？RIII在肿瘤发生和发展中的相对作用尚未被研究，并且仍然是开发针对ST？RIII/T？RIII和转化生长因子-β超家族信号通路的新型治疗药物的根本障碍。来自Prosper的蛋白酶预测和使用TAPI-2的初步数据表明，T？RIII的脱落是由MMP或ADAM家族中的蛋白酶介导的。TAPI-2是一种基质金属蛋白酶(MMPs)和去整合素和金属蛋白酶(ADAM)家族成员的广谱抑制剂。该项目将寻求使用丢失(shRNA，抑制物)和功能获得(表达，重组蛋白)相结合的方法来鉴定与TüRIII脱毛有关的蛋白酶。我们还将研究可溶性和细胞表面TürIII对非锚定细胞生长、迁移、入侵、增殖的生物学贡献， 和T？RIII裂解缺陷的肺腺癌细胞系中的转化生长因子？？信号。为了研究StrIII在体内对癌症发生和发展的贡献，我们正在开发 一种体内T？RIIIM70A/M740A；FSF-KrasG12D/+肺癌模型，其中ST？RIII产生丢失。我们预计，由于在肿瘤形成早期作为肿瘤抑制因子，然后作为肿瘤促进剂的双重作用，TüRIII脱落的丢失将延迟肿瘤的发生，同时促进肿瘤的生长和转移。这项工作将通过从机制上了解ST？RIII的产生所涉及的蛋白酶(S)以及ST？RIII在肺腺癌的发生和发展中的作用来确定细胞表面和ST？RIII在癌症发生中的作用，这可能导致针对T？RIII脱落或转化生长因子？超家族信号通路的新的治疗策略的开发。

 DESCRIPTION (provided by applicant): Transforming growth factor-ß (TGF-ß) is involved in many aspects of cancer biology, including proliferation, apoptosis, migration, and metastasis. TGF-ß's effects are mediated through a family of cell surface receptors, including the type III TGF-ß receptor (TßRIII), which can mediate downstream signaling. TßRIII is lost in many human cancers, including non-small cell lung cancer (NSCLC), with loss correlated with more aggressive disease and disease progression. TßRIII also undergoes ectodomain cleavage, producing a soluble protein (sTßRIII) that may sequester ligand away from the cell surface receptors and prevent activation of TGF-ß signaling. We have demonstrated that the loss of TßRIII shedding, generated through a single base pair mutation in TßRIII (M740A), increases TGF-ß signaling, and inhibits tumorigenicity and metastasis in vivo. However, the mechanism of TßRIII shedding and the relative contributions of sTßRIII versus cell-surface TßRIII to cancer initiation and progression have not been investigated and remain a fundamental barrier to developing novel therapeutic agents that target sTßRIII/TßRIII and TGF-ß superfamily signaling pathways. Protease predictions from PROSPER and preliminary data using TAPI-2, a broad spectrum inhibitor of members of the matrix metalloproteinase (MMP) and a disintegrin and metalloprotease (ADAM) families, suggest that TßRIII shedding is mediated by proteases in the MMP or ADAM family. This project will seek to identify the proteases involved in TßRIII shedding using a combination of loss (shRNA, inhibitors) and gain of function (expression, recombinant protein) approaches. We will also investigate the biological contributions of soluble and cell- surface TßRIII to anchorage-independent cell growth, migration, invasion, proliferation, and TGF-ß signaling in lung adenocarcinoma cell lines that are deficient in TßRIII cleavage. To study the in vivo contributions of sTßRIII to cancer initiation and progression, we are developing an in vivo TßRIIIM70A/M740A;FSF-KrasG12D/+ lung carcinoma model in which there is a loss of sTßRIII production. We anticipate that loss of TßRIII shedding will delay tumorigenesis while promoting tumor growth and metastasis after tumor initiation due to the dual effects of TGF-ß as a tumor suppressor early in carcinogenesis and then later, as a tumor promoter. This work will define the roles of cell surface and sTßRIII in carcinogenesis by providing a mechanistic understanding of the protease(s) involved in the generation of sTßRIII and the contributions of sTßRIII to lung adenocarcinoma development and progression, which may lead to the development of new therapeutic strategies that target TßRIII shedding or TGFß superfamily signaling pathways.