Cyr61-induced breast cancer: Clinical relevance and therapeutic development

描述（由申请人提供）：血管生成因子富半胱氨酸血管生成蛋白61 （Cyr61）是CCN蛋白家族的一员，在乳腺癌的生物侵袭性亚群中过度表达。此外，Cyr61在乳腺细胞中的强制表达促进了裸鼠肿瘤的形成。我们对Cyr61 （n=189个石蜡包埋肿瘤标本）的临床评估显示，30%的浸润性乳腺癌过表达Cyr61， Cyr61的表达与雌激素受体表达和erbB-2过表达呈负相关。这些发现支持Cyr61是乳腺癌进展的一种新的预后标志物的观点。我们最近描述了Cyr61作为一种生存因子的功能，能够降低乳腺癌细胞对微管靶向药物紫杉醇的化学敏感性，紫杉醇是治疗转移性乳腺癌的首选药物。此外，我们证明了精氨酸-甘氨酸-天冬氨酸（RGD）肽模拟物对Cyr61整合素受体α -v- β 3的功能性阻断显著降低了过度表达Cyr61的MCF-7细胞的细胞活力，而对Cyr61阴性对照细胞没有影响。此外，α -v- β 3阻断使MCF- 7/Cyr61细胞对紫杉醇的敏感性恢复到Cyr61阴性对照细胞的水平。我们假设高水平的Cyr61由乳腺癌上皮细胞产生和分泌，与α -v- β 3结合以自分泌方式刺激生长。我们假设cyr61依赖的α -v- β 3驱动的细胞信号激活积极调节乳腺癌细胞存活，从而促进更具侵袭性和化疗耐药的乳腺癌表型。因此，我们假设通过干扰cyr61 - α -v- β 3信号，我们可以同时阻止乳腺癌的转移进展和紫杉醇耐药性。我们的研究不仅旨在评估Cyr61和α -v- β 3之间的相互作用对于诱导乳腺癌的致瘤性、转移和化疗耐药是否必要和/或充分，而且还旨在确定Cyr61是否在乳腺癌的病因学中发挥作用。因此，这种系统的方法将阐明Cyr61在乳腺癌疾病中的预后和预测价值。我们制定了以下目标：1)确定Cyr61表达在乳腺癌进展中的影响，并评估其对治疗决策的意义和临床贡献；2)评估Cyr61在乳腺癌发生和/或促进中的贡献。我们将确定Cyr61如何促进乳腺上皮细胞（正常细胞）的癌前转化，以及Cyr61过表达是否触发乳腺癌前病变的恶性发展。3)评估Cyr61基因表达的特异性沉默是否调节乳腺癌的进展和对化疗诱导的细胞损伤的敏感性。4)确定Cyr61受体α -v- β a3整合素在Cyr61诱导的乳腺癌进展和化疗耐药中的作用；5)确定Cyr61和α -v- β a3之间的功能相互作用对于诱导乳腺上皮细胞的恶性转化、转移进展和/或化疗耐药是否必要和/或充分。总之，我们提出了一种以前未被认识的乳腺癌病因、侵袭性进展和化疗敏感性机制，其中乳腺癌的不同区室不会通过遗传基因突变产生耐药性，而是由于它们暴露于肿瘤微环境中存在的促血管生成生存/生长因子（即Cyr61），通过激活自分泌/旁分泌促生存环(即，Cyr61 / alpha-v-beta3)。此外，我们将评估Cyr61触发的“Cyr61/ α -v- β 3整合素环”作为乳腺癌化疗反应的新预测标志物的相关性。

DESCRIPTION (provided by applicant): The angiogenic factor cysteine-rich angiogenic protein 61 (Cyr61), a member of the CCN protein family, is overexpressed in a biologically aggressive subset of breast carcinomas. Moreover, forced expression of Cyr61 in breast cells promotes tumor formation in nude mice. Our clinical evaluation of Cyr61 (n=189 paraffin embedded tumor specimens) revealed that 30% of invasive breast carcinomas overexpress Cyr61, with Cyr61 expression inversely correlating with estrogen-receptor expression and erbB-2 overexpression. These findings support the notion that Cyr61 is a novel prognostic marker for breast cancer progression. We have recently described that Cyr61 functions as a survival factor capable of decreasing breast cancer cell chemosensitivity to the microtubule-targeting agent Taxol, the drug of choice in the treatment of metastatic breast cancer. Additionally, we demonstrated that functional blockage of the Cyr61 integrin receptor alpha-v-beta3 with arginine-glycine-aspartate (RGD) peptidomimetics markedly decreases cell viability in MCF-7 cells engineered to overexpress Cyr61, whereas it had no effect on Cyr61-negative control cells. Furthermore, alpha-v-beta3 blockade caused Taxol sensitivity in MCF- 7/Cyr61 cells to return to that observed in Cyr61-negative control cells. We hypothesize that high levels of Cyr61 produced and secreted by breast cancer epithelial cells, bind to alpha-v-beta3 to stimulate growth in an autocrine manner. We hypothesize that Cyr61-dependent activation of alpha-v-beta3-driven cellular signaling actively regulates breast cancer cell survival, thus promoting a more aggressive and chemoresistant breast cancer phenotype. Consequently, we hypothesize that by interfering with the Cyr61-alpha-v-beta3 signaling we may concomitantly block metastatic progression and Taxol resistance in breast carcinomas. Our studies are designed not only to evaluate whether the interaction between Cyr61 and alpha-v-beta3 is necessary and/or sufficient to induce breast cancer tumorigenicity, metastasis and chemoresistance but also to determine whether Cyr61 plays a role in the etiology of breast cancer. Therefore, this systematic approach will clarify the prognostic and predictive value of Cyr61 in breast cancer disease. We have formulated the following aims: 1) To determine the impact of Cyr61 expression in breast cancer progression and to evaluate the significance and clinical contribution to the treatment decision, 2) To assess the contribution of Cyr61 in the initiation and/or promotion of breast cancer. We will determine how Cyr61 contributes to the preneoplastic transformation of non-committed breast epithelial cells (normal cells) and whether Cyr61 overexpression triggers the malignant development of pre-neoplastic lesions in the breast, 3) To evaluate whether the specific silencing of Cyr61 gene expression modulates breast cancer progression and sensitivity to chemotherapy-induced cell damage, 4) To determine the involvement of the Cyr61 receptor alpha-v-beta3 integrin in Cyr61-induced breast cancer progression and chemoresistance, and 5) To determine whether a functional interaction between Cyr61 and alpha-v-beta3 is necessary and/or sufficient to induce malignant transformation, metastatic progression and/or chemoresistance in breast epithelial cells. In summary, we propose a previously unrecognized mechanism of breast cancer etiology, aggressive progression and chemosensitivity, in which the different compartments of breast cancer do not develop resistance through heritable genetic mutations, rather, as a result of their exposure to pro-angiogenic survival/growth factors present in the tumor microenvironment (i.e., Cyr61), become metastatic as well as refractory to chemotherapy by activating autocrine/paracrine pro-survival loops (i.e., Cyr61/alpha-v-beta3). In addition, we will evaluate the relevance of a Cyr61- triggered "Cyr61/alpha-v-beta3 integrin loop" as a novel predictive marker for response to chemotherapy in breast cancer.