Caged micelles for co-delivery of SAHA and geldanamycin in cancer therapy

描述（由申请人提供）：近年来，参与调节基因表达和信号转导途径的蛋白质作为治疗耐药癌症的有希望的靶点引起了极大的热情。令人鼓舞的临床前数据显示，这些较新的候选药物可以通过新的作用机制选择性靶向肿瘤细胞，例如亚酰苯胺羟肟酸（SAHA）和格尔达霉素（GA）。每一种药物单独在体外都有惊人的抗肿瘤活性，但SAHA和GA联合使用显示出更好的肿瘤杀伤能力。尽管这些新的抗肿瘤药物对分子靶点具有选择性作用，但其特点是肝毒性高、分布广、静脉注射后消除迅速。因此，显然需要通过多功能载体来改进这些令人兴奋的新药物的联合治疗技术。从实用的角度来看，这可能会减少药理学干预所需的治疗剂量，同时可能降低剂量限制毒性。值得注意的是，单一药物在肿瘤部位的积累是极具挑战性的，当单独的载体或药物用于联合治疗时，情况就更糟了。虽然不是所有的药物组合都需要同时给药（时间可能起关键作用），但SAHA和GA优越的抗肿瘤功效表明，更大的细胞共定位可能在生物肿瘤杀伤中发挥关键作用。为了验证我们的假设，我们提出了四个广泛的具体目标：(1)合成并表征聚(asp-g-ADA)-b-PCL和聚(bCD- peg)-b-PCL分别用于GAp包封（笼状胶束）和SAHA增溶，并验证交联bCD- ada外壳作为SAHA从bCD腔中解离的扩散屏障的存在；(2)利用已建立的难水溶性化合物控释测量方法，研究GAp和SAHA在不同环境条件下的负载和体外释放动力学。(3)利用转铁蛋白靶向的笼养胶束研究GAp与SAHA共递送MCF-7（乳腺）和PC-3（前列腺）细胞的体外抗肿瘤效果；(4)利用转铁蛋白靶向的笼养胶束研究GAp与SAHA在荷瘤小鼠体内的生物抗肿瘤效果。目前的提案是同类研究中第一个通过靶向生物相容性多功能载体研究SAHA与GA联合联合有效联合治疗的方案，其最终长期目标是改善癌症患者侵袭性肿瘤的化疗消退。

DESCRIPTION (provided by applicant): In recent years, proteins involved in regulating gene expression and signal transduction pathways have generated tremendous enthusiasm as promising targets for treating resistant cancers. There are encouraging preclinical data revealing that these newer drug candidates can selectively target tumor cells through novel mechanisms of action, e.g. suberoylanilide hydroxamic acid (SAHA) and geldanamycin (GA). Separately each drug exerts astonishing antitumor activity in vitro, but the combination of SAHA and GA demonstrates superior tumor-kill. Despite their selective methods of action on molecular targets, these new antitumor agents are characterized by high liver toxicities, wide distributions, and rapid eliminations when injected IV. There is therefore a clear need to improve the technology for combination therapy of these exciting new drugs through means of a multifunctional carrier. From a practical point of view, this may reduce the therapeutic dosage required for pharmacological intervention along with a potentially lower dose- limiting toxicity. It is significant to note that accumulation of a single drug at a tumor site is extremely challenging, and becomes even more so when a separate carrier or drug is administered for combination therapy. Although not all drug combinations demand simultaneous delivery (timing may play a critical role), the superior antitumor efficacy of SAHA and GA suggests that greater cellular co-localization may play a critical role in biological tumor-kill. To test our hypothesis, we propose four broad specific aims: (1) to synthesize and characterize poly(asp-g-ADA)-b-PCL and poly(bCD-PEG)-b-PCL for GAp encapsulation (caged micelle) and SAHA solubilization, respectively, and to verify the presence of a crosslinked bCD-ADA shell as a diffusion barrier to SAHA dissociations from bCD cavities, (2) to study the loading and in vitro release kinetics of GAp and SAHA under varying environmental conditions using established methods for measuring controlled release of poorly-water soluble compounds, (3) to study the in vitro antitumor efficacy of GAp and SAHA co-delivery using transferrin-targeted caged micelles in MCF-7 (breast) and PC-3 (prostate) cells, and (4) to study the in vivo biological antitumor efficacy of GAp and SAHA using transferrin- targeted caged micelles in tumor-bearing mice. The current proposal is the first of its kind to investigate co-delivery of SAHA in combination with GA via means of a targeted biocompatible multifunctional carrier for effective combination therapy, with the ultimate long-term goal of improving chemotherapeutic regression of aggressive tumors in cancer patients.