Peptide-mediated delivery of siRNA for treatment of ovarian cancer

描述（由申请人提供）：卵巢癌是女性癌症相关死亡的第五大原因。由于检测方法不足，大多数患者在疾病晚期被诊断出来，并接受手术后化疗的治疗。由于疾病在诊断时处于晚期，复发率很高。卵巢癌的5年生存率比所有癌症的平均5年生存率低20%，这凸显了卵巢癌创新疗法的必要性。快速和廉价的测序技术使人们能够持续努力分析个体癌症基因组，并随后确定新的治疗候选者。然而，针对新发现靶点的小分子抑制剂的开发是昂贵的，缓慢的，并且许多靶点是“不可药物的”。RNAi疗法提供了一个有吸引力的治疗过程：针对新靶标的siRNA可以快速合成，并且可以靶向小分子疗法可能无法实现的特定亚型。然而，在这个阶段，将siRNA有效地递送到病变细胞的细胞质中仍然是一个主要的挑战。我们建议利用原发性卵巢癌细胞作为临床相关的疾病模型来优化卵巢癌治疗的siRNA递送载体。有几种小鼠模型用于开发卵巢癌的治疗方法，包括基因工程小鼠模型和体外繁殖细胞系的异种移植。虽然有用，但这些模型可能不能代表人类高级别卵巢癌的病因，其中大多数源于输卵管。从人类患者的腹水中分离的原代卵巢细胞可能更准确地代表疾病的发展和癌细胞的异质性，因此可能在评估对治疗的反应方面更有用。原发性卵巢癌的特征可能为开发最终将转化为人类的治疗方法提供见解。本提案的目的是开发用于卵巢癌临床相关模型的siRNA递送载体。我们将对我们的第一代载体进行微调，其中包括(1)靶向异位表达p32的肽和(2)介导内化siRNA的内体逃逸的肽。首先，我们将表征原发卵巢癌细胞的表面表征同源受体的我们的靶向肽。接下来，我们将优化靶向肽的体外内化和siRNA在原发性卵巢癌细胞中的传递，并优化其在体内的生物分布。这些优化的载体将被应用于原发性卵巢癌异种移植模型中siRNA的治疗性传递。一种多组分肽siRNA递送载体通过交换靶向部分和货物，具有广泛的适用性，可用于其他癌症亚型。

DESCRIPTION (provided by applicant): Ovarian cancer is the fifth leading cause of cancer-related deaths in women. The majority of patients is diagnosed at late stages of disease due to inadequate detection methods, and is treated with surgery followed by chemotherapy. Due to the advanced stage of disease at diagnosis, there is a high rate of recurrence. The five-year survival rate of ovarian cancer is 20% below the average five-year survival rate for all cancer combined, highlighting the need for innovative therapies for ovarian cancer. Rapid and inexpensive sequencing technology has allowed for the ongoing efforts to profile individual cancer genomes and subsequent identification of new therapeutic candidates. However, the development of small molecule inhibitors against newly identified targets is expensive, slow, and many targets are "undruggable". RNAi therapy offers an attractive course of treatment: siRNA against new targets can be rapidly synthesized and can target specific isoforms which may not be possible by small molecule therapy. However, at this stage, efficient delivery of siRNA into the cytosol of diseased cells remains a major challenge. We propose utilizing primary ovarian cancer cells as a clinically relevant model of disease to optimize siRNA delivery vehicles for ovarian cancer therapy. There are several mouse models utilized to develop therapeutics for ovarian cancer, including genetically engineered mouse models and xenografts of ex vivo propagated cell lines. Although useful, these models may not represent the human etiology of high-grade ovarian cancer, the greater majority of which originate from the fallopian tube. Primary ovarian cells isolated from the ascites of human patients may more accurately represent disease development and the heterogeneity of cancer cells, and therefore may be more useful in evaluating the response to therapy. Characterization of primary ovarian cancers may provide insights to develop therapeutics that will be ultimately translated into humans. The purpose of this proposal is the development of siRNA delivery carriers to clinically relevant models of ovarian cancer. We will fine-tune our first generation carrier which includes (1) a peptide for targeting ectopically expressed p32 and (2) a peptide for mediating endosomal escape of internalized siRNA. First, we will characterize primary ovarian cancer cells for surface representation of the cognate receptor of our targeting peptide. Next, targeting peptide will be optimized for internalization and delivery of siRNA in primary ovarian cancer cells in vitro, as well as optimal biodistribution in vivo. These optimized vehicles will then be applied for therapeutic delivery of siRNA in primary ovarian cancer xenograft models. A multi-component peptide siRNA delivery vehicle has broad applicability to other cancer subtypes via interchanging targeting moieties and cargo.