Inhibition of breast cancer cell metastases using a connexin43 mimetic peptide

项目总结 乳腺癌是确诊最多的癌症之一，也是癌症相关死亡的第二大原因。 在美国女性中，由于异质性和高度动态的性质，治疗仍然具有挑战性 乳房肿瘤。尽管通过筛查进行早期检测在很大程度上导致了乳房发病率的下降 与癌症相关的死亡率、肿瘤复发和转移仍然与预后不良有关。一旦 疾病会转移，中位生存期约为12至15个月。但更令人担忧的是 在三阴性亚型中，乳腺癌是最具侵袭性的类型，在年轻人群中。渐增 有证据表明，上皮-间充质转化过程是该肿瘤转移的一个潜在因素。 子类型。事实上，接受EMT的乳腺癌细胞获得了有助于 转移瘤的形成。此外，EMT导致细胞外基质蛋白表达增加 包括增强肿瘤侵袭、调节癌细胞增殖和限制肿瘤细胞的纤维连接蛋白 对治疗的反应性。因此，迫切需要在乳房中寻找新的分子靶点。 癌症相关EMT，并开发新的治疗方法来防止三阴性乳腺癌的进展 通过转移。在我们之前发表的研究中，我们观察到连接蛋白43(Cx43)缝隙连接的丢失 在EMT过程中伴随细胞内Cx43表达的增加。尽管 在该领域的几项研究中，Cx43在乳腺癌中的作用仍然不明确，在抑制肿瘤中的作用 促进肿瘤生长以及促进肿瘤进展和转移。我们的初步研究确定了一种致癌物质 Cx43通过与微管的相互作用在EMT和三阴性癌细胞中的作用监管 Cx43的定位和活性与体内蛋白质相互作用的多个位点有关 Cx43羧基末端(CT)。Cx43 CT含有微管蛋白结合域，我们开发了一种新的Cx43 由包含微管的Cx43 CT组成的名为JM2(贴膜2)的模拟多肽 结合序列。我们的目标是评估JM2对三阴性乳腺癌的治疗效果。 在体外和体内转移性乳腺癌小鼠模型中基于细胞的检测。我们提出的研究目标是 验证Cx43作为治疗三阴性乳腺癌的新的分子靶点，并利用JM2干扰Cx43- 微管相互作用不影响Cx43的表达，从而更多地调节Cx43的定位和活性 具体地说。这项提议旨在填补知识的空白，在此之前没有研究评估肿瘤的致癌作用。 Cx43与微管相互作用在乳腺癌细胞中的作用及无有效靶向治疗 目前存在能成功消融三阴性乳腺癌细胞转移潜能的药物。

PROJECT SUMMARY Breast cancer is one of the most diagnosed type of cancer and second leading cause of cancer-related death among women in the U.S. Treatment remains challenging due to the heterogeneity and highly dynamic nature of breast tumors. Although early detection through screening has largely contributed to a decline in breast cancer-related mortality, tumor recurrence and metastasis still remain associated with poor prognosis. Once the disease becomes metastatic, the median survival is around 12 to 15 months. But more alarming is the incidence of the triple-negative subtype, the most aggressive type of breast cancer, in the younger population. Increasing evidence identifies the epithelial-mesenchymal transition process as a potential contributor of metastasis in this subtype. In fact, breast carcinoma cells that undergo EMT acquire invasive properties that contribute to the formation of metastases. In addition, EMT results in increased expression of extracellular matrix proteins including fibronectin that enhance tumor invasion, regulate cancer cell proliferation, and limit tumor cell responsiveness to therapies. Therefore, there is an urgent need to identify novel molecular targets in breast cancer-associated EMT, and develop new therapeutics to prevent triple-negative breast cancer progression through metastasis. In our previous published research we observed a loss of connexin43 (Cx43) gap junctions at the plasma membrane concomitantly with an increase in intracellular Cx43 expression during EMT. Despite several studies in the field, the role of Cx43 in breast cancer remains ambiguous with roles in suppressing tumor growth as well as facilitating tumor progression and metastasis. Our preliminary research identifies a tumorigenic role for Cx43 in EMT and triple-negative cancer cells through its interaction with microtubules. Regulating localization and activity of Cx43 is associated with the multiple sites for protein–protein interaction within the Cx43 carboxy-terminus (CT). The Cx43 CT includes a tubulin binding domain and we developed a novel Cx43 mimetic peptide named JM2 (juxtamembrane 2) composed of the Cx43 CT encompassing the microtubule binding sequence. Our goal is to assess the therapeutic effect of JM2 to target triple-negative breast cancer in cell-based assays in vitro and in metastatic breast cancer mouse models in vivo. Our proposed research aims to validate Cx43 as a novel molecular target in triple-negative breast cancer, and use JM2 to disrupt Cx43- microtubule interaction without affecting Cx43 expression, thus regulating Cx43 localization and activity more specifically. This proposal aims to fill a gap in knowledge, whereby no previous studies evaluated the tumorigenic role of Cx43 through interaction with microtubules in breast cancer cells and no efficient targeted therapeutics currently exist that can successfully ablate the metastatic potential of triple-negative breast cancer cells.