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

描述(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。在个体乳腺癌亚型中，那些被归类为三阴性乳腺癌(TNBCs)的乳腺癌在临床上是独一无二的，因为他们表现出侵袭性和转移性的表型，以及他们在常规化疗后迅速复发的高倾向。值得注意的是，TNBCs不表达激素受体(雌激素和孕激素)和ErbB2/HER2，这一表型使靶向化疗(如激素或HER2)无效，并导致TNBC患者预后不良。尽管近年来我们对TNBCs的分子特征和临床表现的了解有所增加，但科学和医学对TNBC的发展和转移仍然缺乏足够的知识，无法合成能够特异性靶向和缓解这一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，它调控细胞的增殖、迁移和黏附，以及细胞的存活。此外，c-Abl可以作为肿瘤发生的抑制者或促进者，以一种细胞和上下文特异的方式发挥作用。重要的是，我们发现，一个结构性活性c-Abl突变体(CST-Abl)的强制表达通过诱导TNBCs经历间充质-上皮转化程序以及上调p21表达和减少基质金属蛋白酶的表达来缓解小鼠TNBC的发展和转移。沿着这些思路，我们最近观察到TNBC的致瘤性与c-Abl表达水平呈负相关，c-Abl表达水平也预测了TNBC对多西他赛的反应。同样，我们发现古老的中草药一叶皂苷对在3D器官型培养中繁殖的TNBCs具有强大的细胞毒活性。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缓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确定致癌转化生长因子β信号转导和机械转导在TNBCs中c-Abl抑瘤功能失活中的作用。我们将积极和消极地操纵整合素1和3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中驱动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。目的2将确定p53成员在c-Abl在TNBCs和其他非TNBC亚型中介导肿瘤抑制中的作用。此外，一种新的变构c-Abl激活剂DPH根除TNBCs的有效性将使用TNBC肿瘤发展的体外和体内模型进行评估。目的3将确定c-Abl预测肿瘤细胞对多西他赛疗效的价值。我们将操纵c-Abl在人和小鼠TNBC细胞系中的表达，其在多西紫杉醇治疗后的存活率将在体外和体内进行评估。同样，我们将对有注解的临床标本进行回顾性研究，以验证c-Abl表达作为预测TNBC对多西紫杉醇反应的生物标志物。最后，目标4将确定一叶珊瑚碱根除TNBCs的疗效。在这里，我们将操纵c-Abl和P53家族成员在晚期TNBCs中的表达，并比较其在一叶菜碱、多西紫杉醇和TNBC标准护理药物治疗下的存活率。总的来说，在这项创新申请中获得的发现将为c-Abl如何抑制TNBC致瘤性提供新的分子见解；它们还将以新的生物标记物(例如，用于多西紫杉醇反应的c-Abl)和TNBCs的治疗选择(例如，赛可林和DPH)的形式产生创新的翻译结果。

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.