Development of dual inhibitors of the kinases SGK1 and AKT1 for blockade of a critical pathway in triple-negative breast cancer

摘要：三阴性乳腺癌是人类乳腺癌中预后最差的一种。一个 造成这一糟糕结果的因素是缺乏有针对性的治疗。主要靶标受体缺失(ER、PR)或不缺失 扩增(HER-2/neu)。细胞毒性化疗仍然是TNBC的主要全身治疗选择 患者，并有危及生命的毒性，如出血，肾脏和心脏损伤。虽然最近的 批准阿替唑单抗与NAB-紫杉醇联合使用是一个开创性的事件，抗PD-L1免疫疗法已经 在TNBC患者中仅取得了适度的应答率。抑制下游的PI3K效应子，如AKT， 已经在临床上被证实是一种治疗方式，但治疗窗口很小。对AKT的抵抗 在TNBC细胞系中也观察到了卡匹西替布等抑制剂。最近的研究表明，血清 糖皮质激素调节蛋白1(SGK1)是治疗TNBC的新靶点。SGK1是一种抗 促进TNBC肿瘤增殖和转移的凋亡激酶，在可检测到的情况下不表达 在正常乳房组织中的水平。尤其是SGK1在间充质干细胞样细胞(MSL)中高表达。 TNBC亚型，占TNBC肿瘤的20%。MSL肿瘤也被归类为克拉丁低， 而MSL/claudin-low肿瘤是TNBC亚型中总体存活率最差的预后之一 和无转移生存期。临床前研究表明，SGK1基因敲除或药理作用 抑制SGK1(我们自己的初步数据)会损害Claudin-low TNBC细胞的增殖和转移。 更多的证据表明，TNBC细胞依赖SGK1来逃避AKT抑制剂诱导的死亡。一位少校 治疗TNBCs的困难在于这些肿瘤的异质性，导致治疗方法多种多样。 结果。我们假设SGK1和AKT1的双特异性抑制可以提供一种新的靶向 克拉丁低TNBC的治疗。先前发现的用于其他适应症的SGK1抑制剂不适合于 细胞功能弱和类药物不足联合应用AKT抑制剂的临床研究进展 属性。使用创新的Leap-to-Lead™技术，我们已经确定了一系列新的双 SGK1/AKT1抑制剂，具有优异的类药物特性，具有细胞效力。在第一阶段SBIR中，我们 将使用结构导向化学优化我们的铅系列的效力、选择性和ADME性能 (应用我们创新的Leap-to-Lead™和BindingSIGHTs设计平台)和房地产驱动型 药物化学方法。然后，新产生的类似物将通过功能细胞分析进行， 用于选择体内化合物的激酶选择性面板、ADME和药代动力学(PK)实验 评估。最后，我们将检验1-2种先导化合物在人TNBC异种移植模型中的有效性。 第一阶段SBIR里程碑的成功完成将证明铅系列的临床前开发是合理的 第二阶段SBIR研究，目标是优化人TNBC和TBC动物模型的体内疗效 确定药理学和毒理学概况，以选择IND研究的主要候选者。

ABSTRACT: Triple negative breast cancers (TNBC) have the worst prognoses of human breast cancers. A factor in this poor outcome is the lack of targeted therapies. Major target receptors are absent (ER, PR) or not amplified (HER-2/neu). Cytotoxic chemotherapy persists as the primary systemic treatment option for TNBC patients, and has life-threatening toxicities such bleeding, and kidney and heart damage. Although the recent approval of atezolizumab in combination with nab-paclitaxel is a seminal event, anti-PD-L1 immunotherapy has achieved only modest response rates in TNBC patients. Inhibition of downstream PI3K effectors, such as AKT, has been clinically validated as a treatment modality but therapeutic windows are small. Resistance to AKT inhibitors such as capivasertib has also been observed in TNBC cell lines. Recent studies have shown serum and glucocorticoid-regulated kinase 1 (SGK1) to be a novel target for treatment of TNBC. SGK1 is an anti- apoptotic kinase that drives proliferation and metastasis of TNBC tumors and is not expressed at detectable levels in normal breast tissue. In particular, SGK1 is overexpressed in the Mesenchymal Stem cell-Like (MSL) subtype of TNBC, which accounts for 20% of TNBC tumors. MSL tumors are also classified as claudin-low, and MSL/claudin-low tumors have one of the poorest prognoses among TNBC subtypes for overall survival and metastasis-free survival. Preclinical studies have shown that SGK1 knockdown or pharmacological inhibition of SGK1 (our own preliminary data) impairs proliferation and metastasis of claudin-low TNBC cells. Additional evidence shows that TNBC cells rely on SGK1 to evade death induced by AKT inhibitors. A major difficulty in treating TNBCs arises from the heterogeneity of these tumors, leading to variable treatment outcomes. We hypothesize that dual specificity inhibition of both SGK1 and AKT1 can provide a novel targeted therapy for claudin-low TNBC. Inhibitors of SGK1 previously discovered for other indications are unsuitable for clinical development in combination with AKT inhibitors due to weak cellular potency and inadequate drug-like properties. Using the innovative Leap-to-Lead™ technology, we have identified a novel series of dual SGK1/AKT1 inhibitors with cellular potency derived from superior drug-like properties. In this Phase I SBIR, we will optimize the potency, selectivity, and ADME properties of our lead series using structure-guided chemistry (applying our innovative Leap-to-Lead™ and BindingSIGHTs design platforms) and a property-driven medicinal chemistry approach. The newly generated analogs will then progress through functional cell assays, kinase selectivity panels, ADME and pharmacokinetic (PK) experiments to select compounds for in vivo evaluation. Finally, we will examine the efficacy of 1-2 lead compounds in a xenograft model of human TNBC. Successful completion of the Phase I SBIR milestones will justify preclinical development of the lead series in Phase II SBIR studies with the goals of optimizing in vivo efficacy in animal models of human TNBC and determining pharmacology and toxicology profiles to select a lead candidate for IND-enabling studies.