Treating Prostate Cancer with RNAi Prodrugs

 描述(申请人提供)：前列腺癌是美国男性的第二大死因。早期发现往往可以通过雄激素阻断或前列腺癌根治术联合局部放射治疗来治疗局部疾病。然而，晚期雄激素抵抗型转移性前列腺癌，即去势抵抗型前列腺癌，由于缺乏治疗，仍然是前列腺癌死亡的主要原因。由于生长因子途径的突变、扩增和/或激活，雄激素受体作为一种转录因子，在没有雄激素的情况下变得结构性地活跃，以驱动细胞生长和生存基因的表达。因此，迫切需要开发针对致癌雄激素受体的新型抗癌治疗药物，雄激素受体是前列腺癌进展和患者死亡的根本驱动因素。RNA干扰(RNAi)反应有很大的潜力靶向整个“不可用药”的基因组，包括靶向致癌的雄激素受体。不幸的是，尽管siRNAs有很好的治疗功能，但由于其带电的磷酸骨架，siRNAs没有进入细胞的能力，需要递送剂。虽然目前的siRNA传递方法足以传递到肝脏，但不幸的是，它们远远不能全身传递到体内需要治疗的所有组织。 转移性前列腺癌。因此，对于肝脏以外的组织，RNAi传递仍然是开发RNAi治疗前列腺癌的技术难题。为了解决RNAi传递问题，我们开创了一种自我传递技术，它从根本上将RNAi疗法缩小到尽可能小的规模，以诱导RNAi反应，称为siRiboNucleic Neighals(SiRNns)。SiRNns代表一种“前药物”方法，其中负电荷直接被生物可逆的磷酸三酯化学基团中和，从而允许单体RNAi分子自我递送到细胞中。一旦进入细胞，酶只存在于细胞内，将中性的siRNN转化为带电的siRNAs，从而诱导RNAi反应。这项R21探索性建议代表了RNAi治疗领域的范式转变，以测试一种针对前列腺癌的单体自我递送siRNN治疗技术，以击倒前列腺癌死亡的关键驱动因素雄激素受体。目的1：通过siRNN RNAi前药靶向前列腺癌雄激素受体我们将在培养中优化PSMA靶向递送和抑制雄激素耐药前列腺癌转移细胞中雄激素受体的siRNns的内体逃逸。目的2.PSMA靶向DD-siRNns在患者来源的转移性前列腺癌小鼠模型中使用患者来源的异种移植的雄激素耐药的前列腺癌股骨转移小鼠模型，我们将优化PSMA靶向体内靶向靶向替代治疗靶基因荧光素酶的siRNN传递，从而实现快速、定量的体内RNAi分析，以优化化学和剂量。

 DESCRIPTION (provided by applicant): Prostate cancer is the second leading cause of death among American men. Early detection often results in promising treatment of local disease by Androgen blockade or radical prostatectomy combined with local radiation treatment. However, late stage Androgen-resistant metastatic prostate cancer, called castration-resistant prostate cancer, remains the leading cause of prostate cancer death due to the lack of treatments. Due to mutation, amplification and/or activation by growth factor pathways, Androgen Receptor, a transcription factor, becomes constitutively active in the absence of androgen to drive expression of cell growth and survival genes. Consequently, there is a great need to develop novel anticancer therapeutics that specifically target oncogenic Androgen Receptor, the root driver of prostate cancer progression and patient death. RNA Interference (RNAi) responses have great potential to target the entire "undruggable" genome, including targeting oncogenic Androgen Receptor. Unfortunately, despite its promising therapeutic features, due to their charged phosphate backbone, siRNAs have no ability to enter cells and require a delivery agent. While current siRNA delivery approaches are sufficient for delivery to the liver, unfortunately they fall far short of systemic delivery to all tissues in the body required to treat metastatic prostate cancer. Thus, for tissues outside the liver, RNAi delivery remains the technological problem to solve for development of RNAi therapeutics to treat prostate cancer. To tackle the RNAi delivery problem, we pioneered a self-delivery technology that radically shrinks RNAi therapeutics to the smallest possible size to induce RNAi responses, called siRiboNucleic Neutrals (siRNNs). siRNNs represent a "Prodrug" approach where the negative charge is directly neutralized by a bioreversible phosphotriester chemical group that allows for self-delivery of monomeric RNAi molecules into cells. Once inside cells, enzymes only present inside of cells, convert neutral siRNNs into charged siRNAs that induce RNAi responses. This R21 exploratory proposal represents a paradigm shift in the RNAi therapeutics field to test a monomeric self-delivering prostate cancer targeted siRNN therapeutic technology to knockdown Androgen Receptor, the key driver of prostate cancer fatalities. Aim 1: Targeting Androgen Receptor by siRNN RNAi Prodrugs in Prostate Cancer We will chemically optimize PSMA-targeted delivery and endosomal escape of siRNNs that knockdown Androgen Receptor in patient-derived androgen-resistant metastatic prostate cells in culture. Aim 2. PSMA Targeted DD-siRNNs in Patient-Derived Metastatic PCa Mouse Models Using patient-derived xenograft femoral metastatic mouse models of androgen-resistant prostate cancer, we will optimize PSMA-targeted siRNN delivery in vivo targeting the surrogate therapeutic target gene Luciferase that allows for rapid, quantitative in vivo RNAi analysis to optimize chemistry and dosing.