Allosteric inhibition of the SHP2 oncoprotein in breast cancer

描述(申请人提供)：乳腺癌是一种异质性疾病，与治疗失败相关的死亡率很高，这主要是由于大多数治疗方法的非特异性。事实上，除了抗人类表皮生长因子受体2(HER2)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不良预后有关，不表达HER2，治疗选择更少。因此，在乳腺癌中寻找新的治疗干预点是一个关键的未得到满足的医学需求。酪氨酸磷酸酶SHP2由众所周知的癌基因PTPN11编码，是靶向癌症治疗的候选基因。大量的现有数据表明，SHP2的催化功能异常是其致癌作用的原因。最近的遗传学证据表明，SHP2确实是HER2阳性和三阴性乳腺癌的一个新的潜在靶点，因为它的消融可以减少肿瘤负担和减少转移进展。为了进一步研究这些现象，这类研究需要高度有效、特异和有效的SHP2抑制剂，其特性使其适合于体内实验。然而，所有已报道的SHP2抑制剂都不能完全满足这些要求。开发这类化合物的主要障碍之一是SHP2相对于其他酪氨酸磷酸酶缺乏化合物选择性。另一个相当大的障碍是，现有的SHP2抑制剂携带一个带电的类似磷酸酪氨酸的基团，这排除了体内充分的化合物暴露。我们合成了对SHP2具有良好选择性的新型变构抑制剂。我们的化合物没有这样的带电部分，因为它们不针对SHP2中的磷酸酪氨酸结合部位。在这里，我们建议定义这些化合物抑制SHP2的基础，以促进现有的先导结构的化学优化，以及未来的药物开发工作。具有进一步提高效力/有效性和适当的药物代谢和药代动力学(DMPK)特性的优化的线索将被用来充分验证SHP2作为乳腺癌治疗的药物靶点。因此，这项建议的首要目标是证明我们的SHP2抑制剂在细胞性乳腺癌模型中的有效性，优化这些药物作为有效的类药物分子，并最终证明它们在乳腺癌体内模型中作为先导剂的潜力。为了实现这些目标，我们将使用X射线结晶学和核磁共振光谱来确定我们的先导化合物(目标1)所针对的新的变构位置(S)。我们将对SHP2抑制剂进行化学优化，以改善溶解性、有效性和DMPK特性，使其适用于体内研究(目标2)。最后，我们将测试优化的SHP2抑制剂的潜力，以抑制a)SHP2依赖的乳腺癌细胞信号，b)乳腺癌细胞的侵袭和增殖。 三维培养和体内，以及c)三阴性乳腺癌小鼠模型中肿瘤的维持、生长和向肺转移的进展(Aim 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).