c-Abl-mediated Suppression of Breast Cancer Development and Metastasis

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，但科学和医学仍然缺乏足够的TNBC发展和转移知识，无法合成能够特异性靶向和减轻这种侵袭性乳腺癌亚型的化疗药物。c-Abl是一种普遍表达的非受体蛋白酪氨酸激酶，它控制细胞增殖、迁移、粘附以及细胞存活。此外，c-Abl可以以细胞和环境特异性的方式作为肿瘤发生的抑制因子或促进因子。重要的是，我们发现，组成型活性c-Abl突变体（CST-Abl）的强化表达减轻了小鼠TNBC的发展和转移，通过诱导TNBC进行间质-上皮过渡程序，结合p21表达的升高，以及基质金属蛋白酶表达的降低来实现。沿着这些线索，我们最近观察到TNBC的致瘤性与c-Abl表达水平呈负相关，这也预测了TNBC对多西紫杉醇的反应。同样，我们发现古中草药Securinine对在3d器官型培养中繁殖的tnbc表现出强大的细胞毒活性。基于这些和其他初步发现，我们假设能够促进c-Abl表达和激活的措施将减轻TNBC的发展和转移进展。这些假设将通过四个具体目标来解决。目的1将确定致癌TGF-¿信号和机械转导在tnbc中灭活c-Abl的抑瘤功能中的作用。我们将通过正、负两种方式调控¿1和¿3整合素及其效应物的表达，以评估它们在TNBC发展和转移进展的特定阶段驱动c-Abl失活的功能。同样，这些分子变化的有效性将使用人类乳腺组织微阵列进行评估。Aim 2将确定p53成员在tnbc和其他非tnbc亚型中介导c-Abl抑制肿瘤中的作用。此外，一种新型变构c-Abl激活剂DPH根除TNBC的有效性将通过体外和体内TNBC肿瘤发展模型进行评估。目的3将确定c-Abl的价值，以预测TNBC对多西他赛的反应。我们将在人类和小鼠TNBC细胞系中操纵c-Abl表达，这些细胞系在多西他赛治疗后的存活将在体外和体内进行评估。同样，我们将对带注释的临床标本进行回顾性研究，以验证c-Abl表达作为TNBC对多西他赛反应的预测性生物标志物。最后，Aim 4将确定Securinine根除tnbc的治疗效果。在这里，我们将在晚期TNBC中操纵c-Abl和p53家族成员的表达，这些TNBC患者在接受Securinine、docetaxel和TNBC标准治疗药物治疗后的生存将被确定和比较。总的来说，在这项创新应用中获得的发现将为c-Abl如何抑制TNBC致瘤性提供新的分子见解；他们还将以新型生物标志物（如多西他赛反应的c-Abl）和tnbc治疗方案（如Securinine和DPH）的形式产生创新的转化结果。

DESCRIPTION (provided by applicant): Breast cancer is a heterogeneous disease comprised of at least 5 major tumor subtypes that coalesce as the 2nd 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 metastasis to permit the synthesis of chemotherapies capable of specifically targeting and alleviating this aggressive breast cancer subtype. c-Abl is a ubiquitously expressed nonreceptor protein tyrosine kinase that governs cell proliferation, migration, and adhesion, as well as that of cell survival. Additionally, c-Abl can function as a suppressor or promoter of tumorigenesis in a cell- and context-specific manner. Importantly, we showed that the enforced expression of a constitutively-active c-Abl mutant (CST-Abl) alleviated TNBC development and metastasis in mice, doing so by inducing TNBCs to undergo mesenchymal-epithelial transition programs coupled to elevated p21 expression, and to diminished expression of matrix metalloproteinases. Along these lines, we recently observed TNBC tumorigenicity to be inversely related to c-Abl expression levels, which also predicts for TNBC response to docetaxel. Likewise, we discovered that the ancient Chinese herb Securinine exhibits potent cytotoxic activity against TNBCs propagated in 3D-organotypic cultures. Based on these and other preliminary findings, we hypothesize that measures capable of promoting c-Abl expression and activation will alleviate TNBC development and metastatic progression. These hypotheses will be addressed by four Specific Aims. Aim 1 will determine the role for oncogenic TGF-¿ signaling and mechanotransduction to inactivate the tumor suppressing functions of c-Abl in TNBCs. We will manipulate, both positively and negatively, the expression of ¿1 and ¿3 integrins and their effectors to gauge their function in driving c-Abl inactivation during specific stages of TNBC development and metastatic progression. Likewise, the validity of these molecular changes will be assessed using a human breast tissue microarray. Aim 2 will determine the role for p53 members in mediating tumor suppression by c-Abl in TNBCs, and in other non-TNBC subtypes. Additionally, the effectiveness of a novel allosteric c-Abl activator, DPH, to eradicate TNBCs will be assessed using in vitro and in vivo models of TNBC tumor development. Aim 3 will determine the value of c-Abl to predict TNBC response to docetaxel. We will manipulate c-Abl expression in human and murine TNBC cell lines, whose survival following docetaxel treatment will be assessed both in vitro and in vivo. Likewise, we will perform a retrospective study on annotated clinical specimens to validate c-Abl expression as a predictive biomarker for TNBC response to docetaxel. Lastly, Aim 4 will determine the therapeutic effectiveness of Securinine to eradicate TNBCs. Here we will manipulate the expression of c-Abl and p53 family members in late-stage TNBCs, whose survival when treated with Securinine, docetaxel, and TNBC standard-of-care agents will be determined and compared. Collectively, the findings obtained in this innovation application will provide novel molecular insights into how c-Abl suppresses TNBC tumorigenicity; they will also generate innovative translational outcomes in the form of novel biomarkers (e.g., c-Abl for docetaxel response) and treatment options (e.g., Securinine and DPH) for TNBCs.