Integrin-mediated Regulation of TGFbeta Signaling and Tumorigenesis

描述（由申请人提供）：乳腺癌是一种异质性疾病，由至少5种主要肿瘤亚型组成，合并为美国女性癌症死亡的第二大原因。在个体乳腺癌亚型中，分类为三阴性乳腺癌（TNBC）的那些通过其侵袭性和转移性表型的呈现以及其在常规化疗治疗后快速复发的高倾向而在临床上是独特的。TNBC还值得注意的是它们不能表达激素受体（雌激素和孕酮）和ErbB 2/HER 2，ErbB 2/HER 2是一种使靶向化疗（例如，激素或HER 2导向的）无效，并导致TNBC患者的不良预后。尽管近年来我们对TNBC的分子特征和临床表现的理解有所增加，但科学和医学仍然缺乏对TNBC发展和进展的足够了解，以允许合成能够特异性靶向和缓解这种致命乳腺癌亚型的新型药物。转化生长因子-β（Transforming growth factor-β，TGF-β）是一种强有力的乳腺肿瘤发生抑制因子.有趣的是，晚期TNBC对TGF-β的反应就好像这种细胞因子是肿瘤促进剂一样，导致获得转移性和干细胞表型。尽管TNBC中TGF-β功能从肿瘤抑制因子向肿瘤促进因子转化的分子机制仍不完全清楚，但我们的实验室最近定义了一种新的基于整合素的信号传导模块，其促进TNBC中的致癌TGF-β信号传导。沿着这些路线，我们发现赖氨酰氧化酶（LOX）的表达和活性有助于致癌TGF-β 1信号传导，部分原因是机械转导的改变。基于这些和其他初步发现，我们假设整合素转换是TNBC驱动的TGF-β 1转移进展的基础。推论表明，开发新的化学治疗剂以防止整联蛋白转换和致癌TGF-β信号传导将显著改善TNBC患者的总体存活率。这些假设将通过四个具体目标来解决。目的1将确定整合素和粘着斑复合物在机械转导引发“TGF-β 1受体”过程中的作用。我们将积极和消极地操纵B1和B3整联蛋白及其效应物的表达，以评估它们在体外和体内将机械转导与TGF-β的致癌活性偶联的功能。同样，将评估机械转导和Smad 2/3信号传导在TNBC转移期间表观遗传学沉默E-钙粘蛋白表达的能力。目的2将确定LOX家族成员在介导TNBC中致癌TGF-β信号传导中的作用。此外，将进行LOX家族成员的遗传和药理学失活以评估它们在驱动TGF-β刺激的TNBC转移中的功能。目的3将绘制与TNBC发展和转移进展相关的转录组和表观遗传事件。将确定通过随机乳晕周围细针抽吸分离的患者乳腺细胞中鉴定的表观遗传标记的存在，以评估其作为预测性TNBC生物标志物的效用。最后，目标4将通过使用双重生物发光成像来可视化TNBC的转移进展期间的TGF-β信号传导。同时，将采用基于CTL 1的MRI方法来监测肿瘤反应性基质的相应变化，并确定常规化疗如何影响这些转移事件。总的来说，这些研究将提供关于TGF-β 1、整合素和机械转导如何在促进TNBC的EMT、侵袭和转移中合作的有价值的信息，更重要的是，关于如何通过灭活TGF-β 1的致癌活性来控制这些致命过程的有价值的信息。此外，将我们的表观遗传生物标志物转化为临床诊断应用将使科学和医学能够显着提高TNBC患者的总体生存率。

DESCRIPTION (provided by applicant): Breast cancer is a heterogeneous disease comprised of at least 5 major tumor subtypes that coalesce as the second leading cause of cancer death in women in the United States. Amongst individual breast cancer subtypes, those classified as being triple-negative breast cancers (TNBCs) are clinically unique via their presentation of aggressive and metastatic phenotypes, and their high propensity to recur rapidly following conventional chemotherapy treatment. TNBCs are also noteworthy by their failure to express hormone receptors (estrogen and progesterone) and ErbB2/HER2, a phenotype that renders targeted chemotherapies (e.g., hormonal or HER2-directed) ineffective and contributes to the poor prognosis of TNBC patients. Although our understanding of the molecular features and clinical manifestations of TNBCs has increased in recent years, science and medicine still lack sufficient knowledge of TNBC development and progression to permit the synthesis of novel pharmaceuticals capable of specifically targeting and alleviating this lethal breast cancer subtype. Transforming growth factor-ß (TGF-ß) is a powerful suppressor of mammary tumorigenesis. Interestingly, late-stage TNBCs respond to TGF-ß as if this cytokine were a tumor promoter, leading to the acquisition of metastatic and stem cell phenotypes. Although the molecular mechanisms underlying the conversion of TGF-ß function from that of a tumor suppressor to a tumor promoter in TNBCs remains incompletely understood, our laboratory recently defined a novel integrin-based signaling module that facilitates oncogenic TGF-ß signaling in TNBCs. Along these lines, we find the expression and activity of lysyl oxidase (LOX) to contribute to oncogenic TGF-ß signaling in part due to alterations in mechanotransduction. Based on these and other preliminary findings, we hypothesize that integrin switching underlies metastatic progression of TNBCs driven TGF-ß. A corollary states that developing novel chemotherapeutics to prevent integrin switching and oncogenic TGF-ß signaling will significantly improve the overall survival rates of TNBC patients. These hypotheses will be addressed by four Specific Aims. Aim 1 will determine the role of integrins and focal adhesion complexes during initiation of the "TGF-ß Paradox" by mechanotransduction. We will manipulate, both positively and negatively, the expression of B1 and B3 integrin and their effectors to gauge their function in coupling mechanotransduction to the oncogenic activities of TGF-ß both in vitro and in vivo. Likewise, the ability of mechanotransduction and Smad2/3 signaling to epigenetically silence E-cadherin expression during TNBC metastasis will be assessed. Aim 2 will determine the role of LOX family members in mediating oncogenic TGF-ß signaling in TNBCs. Additionally, genetic and pharmacological inactivation of LOX family members will be undertaken to assess their function in driving TNBC metastasis stimulated by TGF-ß. Aim 3 will map the transcriptome and epigenetic events coupled to TNBC development and metastatic progression. The presence of identified epigenetic marks in patient breast cells isolated by random periareolar fine needle aspiration will be determined to assess their utility as predictive TNBC biomarkers. Lastly, Aim 4 will visualize TGF-ß signaling during metastatic progression of TNBCs through the use of dual bioluminescent imaging. Simultaneous CTL1-based MRI approaches will be employed to monitor corresponding changes in tumor reactive stroma, as well as determine how conventional chemotherapies impact these metastatic events. Collectively, these studies will provide valuable information on how TGF-ß, integrins, and mechanotransduction cooperate in promoting the EMT, invasion, and metastasis of TNBCs, and more importantly, on how to control these deadly processes by inactivating the oncogenic activities of TGF-ß. Moreover, translating our epigenetic biomarkers to clinical diagnostic applications will enable science and medicine to significantly improve the overall survival of patients with TNBCs.