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，是美国女性癌症死亡的第二大原因。在单个乳腺癌亚型中，那些被归类为三阴性乳腺癌（tnbc）的患者在临床上是独一无二的，因为它们具有侵袭性和转移性表型，并且在常规化疗治疗后迅速复发的高倾向。TNBC还值得注意的是，它们不能表达激素受体（雌激素和黄体酮）和ErbB2/HER2，这种表型使得靶向化疗（例如激素或HER2导向）无效，并导致TNBC患者预后不良。尽管近年来我们对TNBC的分子特征和临床表现的了解有所增加，但科学界和医学界对TNBC的发展和进展仍然缺乏足够的了解，无法合成能够特异性靶向和减轻这种致命乳腺癌亚型的新药。转化生长因子-？（TGF-?）是乳腺肿瘤发生的有效抑制因子。有趣的是，晚期tnbc对TGF-？似乎这种细胞因子是肿瘤启动子，导致获得转移性和干细胞表型。虽然TGF-?转化的分子机制tnbc中从肿瘤抑制因子到肿瘤启动因子的功能仍然不完全清楚，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，促进致癌TGF-？tnbc中的信号。沿着这些思路，我们发现赖氨酸氧化酶（LOX）的表达和活性有助于致癌的TGF-？信号部分是由于机械转导的改变。基于这些和其他初步发现，我们假设整合素转换是tnbc驱动TGF-?转移进展的基础。一项推论表明，开发新的化疗药物来防止整合素转换和致癌的TGF-？信号转导将显著提高TNBC患者的总生存率。这些假设将通过四个具体目标来解决。目的1将通过机械转导确定整合素和局灶黏附复合物在“TGF-B悖论”启动过程中的作用。我们将对B1和B3整合素及其效应物的表达进行正、负操作，以评估它们在TGF-？无论是体外还是体内。同样，将评估机械转导和Smad2/3信号传导在TNBC转移过程中表观遗传沉默E-cadherin表达的能力。Aim 2将确定LOX家族成员在介导致癌TGF-？tnbc中的信号。此外，将对LOX家族成员进行遗传和药理学失活，以评估其在驱动TGF-B刺激的TNBC转移中的作用。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。通过随机乳晕周围细针抽吸分离的患者乳腺细胞中确定的表观遗传标记的存在将被确定，以评估其效用

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-? (TGF-?) is a powerful suppressor of mammary tumorigenesis. Interestingly, late-stage TNBCs respond to TGF-? 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-? 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-? signaling in TNBCs. Along these lines, we find the expression and activity of lysyl oxidase (LOX) to contribute to oncogenic TGF-? 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-?. A corollary states that developing novel chemotherapeutics to prevent integrin switching and oncogenic TGF-? 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-B 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-? 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-? 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-B. 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-? 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-?, 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-?. Moreover, translating our epigenetic biomarkers to clinical diagnostic applications will enable science and medicine to significantly improve the overall survival of patients with TNBCs.