Itraconazole Analogues to Treat Medulloblastoma

描述（由申请人提供）：hedgehog （Hh）通路是一种发育信号通路，在胚胎发育过程中指导生长和组织模式发挥关键作用。Hh信号的失调有助于多种人类肿瘤的发展，最显著的是基底细胞癌（BCC）和髓母细胞瘤（MB）。最近，一种Hh信号的小分子抑制剂GDC-0449被批准用于晚期BCC的治疗，这为该途径具有临床相关性提供了证据。GDC-0449结合并抑制smoothened (Smo)，该通路的关键调节因子是临床前和临床开发中多种小分子Hh通路抑制剂的细胞靶点；然而，Smo突变导致对GDC-0449耐药的MB形式，突出了继续开发Hh通路抑制剂的必要性。伊曲康唑（Itraconazole， ITZ）是三唑类抗真菌药物中的一员，最近在体外和体内被发现是一种有效的Hh信号抑制剂（IC50值= 270 - 690 nM）。最重要的是，ITZ保持了对多种突变型Smo的抑制活性，这些突变型Smo赋予GDC-0449耐药性，并延长了GDC-0449耐药型MB小鼠的存活时间。尽管其抗hh活性很有希望，但ITZ表现出较差的溶解性，并抑制CYP3A4，这是一种有害的副作用，导致多种药物相互作用，并且在使用ITZ时需要仔细监测饮食和药物方案。Hadden实验室对ITZ介导的Hh抑制进行了初步的构效关系（SAR）研究，发现了ITZ支架的多个可修饰区域。我们的数据表明，对这些区域的进一步修改将提供维持有效或增强Hh抑制的ITZ类似物，同时也显示出改善的药代动力学参数和减少ITZ治疗特征的脱靶副作用。本提案所述研究的总体目标是开发一类基于ITZ支架的改进Hh通路抑制剂，作为潜在的抗癌化疗药物。根据这一核心原则，一个由药物化学家和癌症生物学家组成的合作小组将承担以下具体目标：(1)合成并表征针对Hh信号通路的ITZ类似物，(2)评估Aim 1中制备的ITZ类似物的体外活性，(3)评估铅IT类似物在Hh依赖性癌症小鼠模型中的体内活性。ITZ作为Hh通路抑制剂的鉴定为探索这种临床有效的抗真菌药物的潜在治疗应用开辟了新的途径，并为设计、合成和评估一类新的Hh通路抑制剂提供了独特的框架。

DESCRIPTION (provided by applicant): The hedgehog (Hh) pathway is a developmental signaling pathway that plays a key role in directing growth and tissue patterning during embryonic development. Dysregulation of Hh signaling contributes to the development of a variety of human tumors, most notably basal cell carcinoma (BCC) and medulloblastoma (MB). A small molecule inhibitor of Hh signaling, GDC-0449, was recently approved for the treatment of advanced BCC, providing evidence that this pathway has clinical relevance. GDC-0449 binds and inhibits smoothened (Smo), a key regulator of the pathway that is the cellular target of multiple small molecule Hh pathway inhibitors in pre-clinical and clinical development; however, mutations in Smo resulted in forms of MB resistant to GDC-0449, highlighting the need for continued development of Hh pathway inhibitors. Itraconazole (ITZ), a member of the triazole class of antifungal agents, was recently identified as a potent inhibitor of Hh signaling in vitro and in vivo (IC50 values = 270 - 690 nM). Most importantly, ITZ maintains inhibitory activity against multiple mutant forms Smo that confer resistance to GDC-0449 and prolongs survival of mice with GDC-0449 resistant forms of MB. Despite its promising anti-Hh activity, ITZ exhibits poor solubility and inhibits CYP3A4, a detrimental side effect that results in multiple drug-drug interactions and requires careful monitoring of diet and drug regimens when ITZ is administered. Preliminary structure-activity relationship (SAR) studies for ITZ-mediated Hh inhibition performed in the Hadden lab have identified multiple regions of the ITZ scaffold that are amenable to modification. Our data suggests that further modifications to these regions will provide ITZ analogues that maintain potent or enhanced Hh inhibition, while also demonstrating improved pharmacokinetic parameters and reduced off-target side effects characteristic of ITZ treatment. The overall goal of the studies described in this proposal is to develop a class of improved Hh pathway inhibitors based on the ITZ scaffold as potential anti-cancer chemotherapeutics. With respect to this central tenet, a collaborative group of medicinal chemists and cancer biologists will undertake the following specific aims: (1) synthesize and characterize ITZ analogues designed to target the Hh signaling pathway, (2) evaluate the in vitro activity of ITZ analogues prepared in Aim 1, and (3) evaluate the in vivo activity of lead IT analogues in murine models of Hh-dependent cancer. The identification of ITZ as an Hh pathway inhibitor has opened a new avenue of exploration into potential therapeutic applications of this clinically efficacious antifungal and represents a unique scaffold for the design, synthesi, and evaluation of a new class of Hh pathway inhibitors.