Targeted delivery of IKKalpha siRNA to prostate cancer cells

描述（由申请人提供）：前列腺癌是最常见的男性恶性肿瘤，也是美国男性癌症死亡的第二大原因。目前的标准治疗方法包括手术、放疗或辅助激素治疗。虽然这些治疗在短期内相对有效，但大多数最初诊断为局限性前列腺癌的患者最终都会复发。因此，前列腺癌患者面临的主要风险是发展到转移。人们正在加紧努力开发治疗前列腺癌的方法。在所有方法中，基因调控是最有希望的策略之一，因为基因组不稳定是癌症发展的标志。最近发现IKK1是前列腺上皮细胞转移命运的关键激活因子。这项应用是首次尝试通过使用小干扰RNA （siRNA）沉默IKK1基因表达来评估其体内治疗效果。我们已经鉴定出一种有效的IKK1 siRNA，并证明其能够抑制两种前列腺癌细胞的迁移。我们将设计一种靶向递送策略，将siRNA递送到前列腺癌细胞中。目的是开发一种靶向IKK1基因的适配体偶联siRNA （aptamer-siRNA）来治疗前列腺癌。为了克服siRNA治疗应用的两大障碍：体内稳定性和靶向性，将进行主干修饰和配体偶联。这项研究的结果可能导致有效的siRNA治疗前列腺癌。我们的总体假设是，IKK1 siRNA通过与一种能够识别并结合前列腺癌细胞表面PSMA（前列腺特异性膜抗原）的适配体结合，将IKK1 siRNA靶向递送到肿瘤细胞中，从而抑制前列腺癌细胞的生长和转移（图1）。我们将测试以下具体假设：i)沉默IKK1可以抑制前列腺癌细胞的侵袭特性；ii)沉默IKK1可恢复Maspin基因的表达；iii) IKK1 siRNA意义链上的2’-OMe修饰将在不干扰其沉默作用的情况下增加其体内稳定性；iv)抗psma适配体与siRNA结合将增加前列腺癌细胞对其的摄取；v)在小鼠前列腺癌模型中，肿瘤细胞中siRNA摄取的增加与更高的抗转移作用相关。

DESCRIPTION (provided by applicant): Prostate cancer is the most common male malignancy and the second leading cause of cancer death in American men. The current standard therapies include surgery, radiation or adjuvant hormonal therapy. Although these therapies are relatively effective in the short-term, majority of patients initially diagnosed with localized prostate cancer ultimately relapse. Therefore, the major risk faced by prostate cancer patients is the development to metastasis. Intensive efforts are underway to develop therapeutics for the treatment of prostate cancer. Among all approaches, gene modulation is one of the most promising strategies due to the fact that genomic instability is the hallmark of cancer development. IKK1 is recently identified as the critical activator of prostatic epithelia cells to the metastatic fate. This application is the first attempt to evaluate the in vivo therapeutic efficacy of IKK1 by silencing its gene expression using small interfering RNA (siRNA). We have identified one potent IKK1 siRNA and demonstrated its ability to inhibit the migration of two prostate cancer cells. We will design a targeted delivery strategy to deliver the siRNA to prostate cancer cells. The objective is to develop an aptamer conjugated siRNA (aptamer-siRNA) targeting IKK1 gene to treat prostate cancer. Backbone modification and ligand conjugation will be conducted to overcome two obstacles of siRNA's therapeutic application: the in vivo stability and target-ability. The results of this study can lead to efficient siRNA therapeutics against prostate cancer. Our overall hypothesis is that the prostate cancer cells' growth and metastasis can be inhibited by the targeted delivery of IKK1 siRNA to tumor cells via conjugation with an aptamer which can recognize and bind to the PSMA (prostate specific membrane antigen) on the surface of prostate cancer cells (Fig. 1). We will test following specific hypotheses: i) silencing IKK1 can inhibit the invasive properties of prostate cancer cells; ii) silencing IKK1 could restore the gene expression of Maspin; iii) 2'-OMe modification in the sense strand of IKK1 siRNA will increase the in vivo stability without interfering its silencing effect; iv) conjugation of the anti-PSMA aptamer to siRNA will increase its uptake by prostate cancer cells; v) the increased uptake of siRNA in the tumor cells will correlate with higher anti-metastasis effect in the mouse prostate cancer model. PUBLIC HEALTH RELEVANCE: Prostate cancer is the most common male malignancy and the second leading cause of cancer death in American men. Successful accomplishment of this project will provide an effective therapeutics to treat prostate cancer.