Allosteric inhibition of the SHP2 oncoprotein in breast cancer

描述（由申请人提供）：乳腺癌是异质性疾病，具有与治疗失败相关的显著死亡率，这主要是由于大多数治疗的非特异性。事实上，除了抗人表皮生长因子受体2（HER 2）药物外，大多数乳腺癌治疗都是通过全身毒性起作用的。三阴性乳腺癌与高侵袭性和预后不良相关，不能表达HER 2，治疗选择更少。因此，寻找乳腺癌的新治疗干预点是一个关键的未满足的医疗需求。酪氨酸磷酸酶SHP 2由已知的癌基因PTPN 11编码，是靶向癌症治疗的候选者。大量的现有数据表明，SHP 2的异常催化功能是其致癌作用的原因。最近的遗传学证据表明，SHP 2确实是HER 2阳性和三阴性乳腺癌的一个新的潜在靶点，因为它的消融导致肿瘤负荷降低和转移进展减少。为了进一步研究这些现象，这些研究需要具有使其适合于体内实验的特性的高度强效、特异性和有效的SHP 2抑制剂。然而，所报道的SHP 2抑制剂中没有一种完全满足这些要求。开发此类化合物的主要障碍之一是相对于其他酪氨酸磷酸酶缺乏对SHP 2的化合物选择性。另一个相当大的障碍是现有的SHP 2抑制剂携带带电的磷酸酪氨酸模拟基团，这妨碍了体内充分的化合物暴露。我们已经产生了对SHP 2具有优异选择性的新型变构抑制剂。我们的化合物不具有这样的带电部分，因为它们不靶向SHP 2中的磷酸酪氨酸结合位点。在这里，我们建议定义这些化合物抑制SHP 2的基础，以促进现有先导结构的化学优化，以及未来的药物发现工作。具有进一步增加的效力/功效和合适的药物代谢和药代动力学（DMPK）性质的优化的先导物将用于充分验证SHP 2作为乳腺癌治疗的药物靶标。因此，该提案的总体目标是证明我们的SHP 2抑制剂在细胞乳腺癌模型中的功效，优化作为强效药物样分子的药剂，并最终证明其作为乳腺癌体内模型中的先导药剂的潜力。为了实现这些目标，我们将使用X射线晶体学和NMR光谱来鉴定我们的先导化合物所靶向的新型变构位点（目标1）。我们将对SHP 2抑制剂进行化学优化，以改善溶解度、功效和DMPK特性，使其适用于体内研究（目的2）。最后，我们将测试优化的SHP 2抑制剂抑制a）乳腺癌细胞中的SHP 2依赖性信号传导，B）乳腺癌细胞中的侵袭和增殖的潜力。 三维培养和体内，和c）在三阴性乳腺癌小鼠模型中的肿瘤维持、生长和向肺转移的进展（目的3）。

DESCRIPTION (provided by applicant): Breast cancers are heterogeneous diseases with significant mortality associated with failed treatment, and this is primarily due to the non-specifc nature of most therapies. Indeed, with the notable exception of anti-human epidermal growth factor receptor 2 (HER2) agents, most breast cancer therapies act through generalized toxicity. Triple-negative breast cancers, which are associated with high aggressiveness and poor prognosis, fail to express HER2 and have even less treatment options. Thus, the search for new therapeutic intervention points in breast cancers is a crucial unmet medical need. The tyrosine phosphatase SHP2, encoded by the well-known oncogene PTPN11, is a candidate for targeted cancer therapy. A plethora of existing data demonstrates that aberrant catalytic function of SHP2 is responsible for its oncogenic effects. Recent genetic evidence indicates that SHP2 is indeed a novel potential target in HER2-positive and triple negative breast cancers, as its ablation results in decreased tumor burden and reduced metastatic progression. To further investigate these phenomena, such studies require highly potent, specific, and efficacious SHP2 inhibitors with properties that make them suitable for in vivo experiments. However, none of the reported SHP2 inhibitors fully satisfies these requirements. One of the major obstacles in developing such compounds is the lack of compound selectivity for SHP2 over other tyrosine phosphatases. Another considerable hurdle is presented by the fact that existing SHP2 inhibitors carry a charged phosphotyrosine-mimicking group that precludes sufficient compound exposure in vivo. We have generated novel allosteric inhibitors with excellent selectivity for SHP2. Our compounds do not have such a charged moiety as they do not target the phosphotyrosine binding site in SHP2. Here, we propose to define the basis of SHP2 inhibition by these compounds in order to facilitate chemical optimization of existing lead structures, as well as future drug discovery efforts. Optimized leads with further increased potency/ efficacy and suitable drug metabolism and pharmacokinetics (DMPK) properties will be utilized to fully validate SHP2 as drug target for breast cancer therapy. The overarching objectives of this proposal therefore are to demonstrate the efficacy of our SHP2 inhibitors in cellular breast cancer models, to optimize the agents as potent drug like molecules, and finally to demonstrate their potential as lead agents in in vivo models of breast cancers. To achieve these objectives, we will use X-Ray crystallography and NMR spectroscopy to identify the novel allosteric site(s) targeted by our lead compounds (Aim 1). We will chemically optimize the SHP2 inhibitors for improved solubility, efficacy, and DMPK properties to make them suitable for in vivo studies (Aim 2). Finally, we will test optimized SHP2 inhibitors for their potential to inhibit a) SHP2-dependent signaling in breast cancer cells, b) invasion and proliferation of breast cancer cells in three-dimensional culture and in vivo, and c) tumor maintenance, growth, and progression to lung metastases in triple negative breast cancer mouse models (Aim 3).