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，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发展和转移的足够了解，以允许合成能够特异性靶向和缓解这种侵袭性乳腺癌亚型的化疗。c-Abl是一种普遍表达的非受体蛋白酪氨酸激酶，其控制细胞增殖、迁移和粘附以及细胞存活。此外，c-Abl可以以细胞特异性和环境特异性方式作为肿瘤发生的抑制剂或促进剂发挥作用。重要的是，我们表明，组成型活性c-Abl突变体（CST-Abl）的强制表达减轻了小鼠中TNBC的发展和转移，通过诱导TNBC经历间充质-上皮转化程序来实现这一点，该程序与升高的p21表达和减少的基质金属蛋白酶表达相关联。沿着这些路线，我们最近观察到TNBC致瘤性与c-Abl表达水平负相关，这也预测了TNBC对多西他赛的反应。同样，我们发现古老的中国草药一叶Securinine对在3D器官型培养物中繁殖的TNBC表现出有效的细胞毒性活性。基于这些和其他初步发现，我们假设能够促进c-Abl表达和活化的措施将缓解TNBC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将确定致癌性TGF-β信号传导和机械转导在证实c-Abl在TNBC中的肿瘤抑制功能中的作用。我们将积极和消极地操纵<$1和<$3整合素及其效应物的表达，以衡量它们在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。目的2将确定p53成员在TNBC和其他非TNBC亚型中介导c-Abl的肿瘤抑制中的作用。此外，将使用TNBC肿瘤发展的体外和体内模型评估新型变构c-Abl激活剂DPH根除TNBC的有效性。目的3将确定c-Abl预测TNBC对多西他赛的反应的值。我们将操纵人和鼠TNBC细胞系中的c-Abl表达，将在体外和体内评估多西他赛治疗后的存活率。同样，我们将对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生物标志物。最后，目标4将确定一叶秋碱根除TNBC的治疗有效性。在这里，我们将操纵c-Abl和p53家族成员在晚期TNBC中的表达，将确定并比较用一叶Securinine、多西他赛和TNBC标准治疗剂治疗时的存活率。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志物（例如，多西他赛反应的c-Abl）和治疗选择（例如，一叶秋碱和DPH）。

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.