Optimization of SWCNT/siRNA complex formulation for tumor accumulation

简介（由申请人提供）：Ensysce Biosciences Inc.是一家位于德克萨斯州休斯顿的生物技术公司，利用1996年底诺贝尔奖获得者莱斯大学Richard Smalley博士的开创性纳米技术研究。Smalley博士在治疗领域的碳纳米管技术工作的权利，以及其他关键的碳纳米管专利，已经由ensyce授权或申请，该公司已经启动了一些利用碳纳米管治疗癌症的研究项目，包括本文所述的递送短干扰rna （siRNA）。Ensysce对单壁碳纳米管（SWCNT）递送系统的兴趣跨越了包括rna递送在内的许多治疗模式。siRNA是一种双链RNA的小片段，人们正在探索它以一种高度特异性的方式控制癌症的生长。然而，需要有效的手段将RNAi传递到肿瘤细胞中。ensyce的数据显示，经静脉给药的SWCNT/siRNA复合物几乎没有毒性，在肿瘤中积累，并产生肿瘤靶蛋白敲除和抗肿瘤活性。ensyce目前正在探索优化肿瘤积累和产生强大抗肿瘤活性的方法。ensyce的数据还表明，循环的swcnts /siRNA复合物的半衰期会影响其生物分布，尽管在动物模型中发现，即使短t1/2的复合物也能在人类肿瘤异种移植物中产生良好的抗肿瘤活性。本提案将对swcnts /siRNA的多种制剂进行全面检查，以确定其静脉给药后的肿瘤和组织分布。最有希望的肿瘤与组织分布的制备将进一步使用siRNA进行KRAS的抗肿瘤效果检测。突变体KRAS （mutt -KRAS）是典型的不可药物的癌症靶点。在许多癌症类型中，25%的患者肿瘤中都发现了这种基因。据估计，2012年美国将有32万人被诊断患有mut-KRAS，其中大多数人将死于这种疾病。目前尚无针对KRAS的治疗方法，而寻找KRAS的有效治疗方法可以说是当今癌症领域最重要的尚未满足的医疗需求。因此，通过swcnts传递的siRNA减少其存在为解决这一致命问题提供了方法。因此，该项目将广泛评估一些系统递送的swcnts复合物的生物分布特性，并将提供有关swcnts /siRNA复合物在肿瘤中的功效的数据。最终，这项工作将为使用一种强大的新型siRNA传递系统铺平道路，该系统有可能在临床治疗癌症的过程中抑制许多不同的致癌靶点。

DESCRIPTION (provided by applicant): Ensysce Biosciences Inc. is a biotechnology company located in Houston, TX, exploiting the pionering nanotechnology studies of the late 1996 Nobel Laureate, Dr. Richard Smalley of Rice University. The rights to Dr. Smalley's work on carbon nanotube technology in the area of therapeutics, as well as other critical carbon nanotube patents, have been in-licensed or applied for by Ensysce and the company has initiated a number of research programs to utilize carbon nanotubes to treat cancer including that described herein to deliver short interfering RNAs (siRNA). Ensysce's interest in the single-walled carbon nanotubes (SWCNT) delivery system spans a number of therapeutic modalities including the delivery of RNAis. siRNA, are a type of small segments of double- stranded RNA that are being explored to control cancer growth in a highly specific fashion. However, efficient means are needed to deliver the RNAi into tumor cells. Ensysce's data show that the solubilized SWCNT/siRNA complexes delivered to mice intravenously cause little to no toxicity, accumulate in tumor and produce tumor target-protein knockdown and antitumor activity. Ensysce is now exploring means to optimize the tumor accumulation and produce robust antitumor activity. Ensysce data has also shown that circulating the half-life of SWCNT/siRNA complex affect its biodistribution, although complexes with even short t1/2 were found to produce god antitumor activity in human tumor xengrafts in animal models. This proposal will undertake a comprehensive examination of a number of formulations of SWCNT/siRNA to determine their tumor and tissue distribution following intravenous administration. The preparation with the most promising tumor versus tissue distribution will be further examined for antitumor eficacy using siRNA for KRAS. Mutant KRAS (mut-KRAS) is the prototypical undruggable cancer target. It is found in 25% of patient tumors across many cancer types and an estimated 320,000 individuals who will be diagnosed with mut-KRAS in the US in 2012 most of who will die of their disease. There is no treatment for KRAS and finding effective therapies for KRAS is arguably the single most important unmet medical need in cancer today. Therefore reducing its presence with siRNA delivered by SWCNT provides approach to this deadly problem. Hence, this project will extensively evaluate the biodistribution properties of a number of SWCNT complexes delivered systemically and will provide data on the efficacy of SWCNT/siRNA complexes in tumors. Ultimately, this work will pave the way for the use of a powerful new siRNA delivery system with the potential for inhibiting many different cancer causing targets in a clinical setting for the treatment of cancer. PUBLIC HEALTH RELEVANCE: Novel selective cancer therapies are still needed to improve outcome for patients without unnecessary toxic side effects. Short interfering RNA (siRNA) is one such potential modality as it can block the activity of genes that are essential for the cancer growth but not for normal tissue. However, the major barrier to the development of clinical siRNA therapies is the lack of an effective delivery mechanism to administer it to a patient and carry it into the tumor cell. Ensysce's research has shown that single-walled carbon nanotubes (SWCNT) can complex with siRNA and act as a delivery vehicle to carry siRNA into cancer cells hence providing a selective therapeutic outcome. To ensure delivery of the siRNA to tumors it has been found that the circulation time (half-life) of the complexes is important. This proposal will undertake a comprehensive examination of a number of SWCNT preparations with a range of circulation half-lives to determine the tumor and tissue distribution following intravenous administration. The preparation with the most promising tumor versus tissue distribution will be further examined for antitumor activity in combination with another cancer therapy. These critical studies will move this novel technology one step closer to full pre-clinical development and eventually to a clinical trial study.