Tumor-targeted silencing of Bcl-2/Bcl-xL by the self-assembled siRNA-nanovectors

通过自组装 siRNA 纳米载体对 Bcl-2/Bcl-xL 进行肿瘤靶向沉默

• 批准号: 7115416
• 负责人: Liang Xu
• 金额: $ 26.63万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-27 至 2011-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7115416
• 关键词: human; neoplasm /cancer

DESCRIPTION (provided by applicant): Anti-apoptotic proteins Bcl-2 and Bcl-xL are overexpressed in many cancers and contribute to tumor initiation, progression and resistance to therapy. Molecular modulation of Bcl-2/Bcl-xL represents a promising strategy for overcoming the resistance to apoptosis induced by current cancer therapy. The potent, sequence-specific gene silencing by small interfering RNA (siRNA) has become a powerful tool in cancer research and holds significant potential as novel molecular therapy for cancer. However, delivering the siRNA-based therapeutics efficiently and specifically to tumor and its metastases remains a great challenge. We have developed a tumor-specific, ligand-targeting, self-assembled DNA-nanovector system which shows promising efficiency and specificity in targeted delivery of various genes and anti-sense oligonucleotides to human cancer, with limited effect on normal tissues (US Patent No. 6,749,863). We have also designed siRNAs for human Bcl-2 and Bcl-xL that can potently knock-down Bcl-2/Bcl-xL leading to extensive cancer cell death (US Patent pending). We propose to use our patented nanovector system to develop siRNA-based therapeutics for tumor- targeted silencing of Bcl-2/Bcl-xL. We will test two inter-related hypotheses: (1) Tumor-targeted delivery of siRNA will efficiently silence Bcl-2/Bcl-xL, and induce apoptosis in human cancer cells that depend on Bcl- 2/Bcl-xL for survival; (2) Knock-down of the anti-apoptotic Bcl-2/Bcl-xL in turn will overcome resistance and restore sensitivity of cancer cells to chemo/radiotherapy. Our long-term goal is to develop the tumor- targeting siRNA-nanovectors as novel molecular therapy targeting Bcl-2/Bcl-xL for human cancers with Bcl- 2/Bcl-xL over-expression. To test our hypothesis, we propose to carry out three SPECIFIC AIMS: AIM 1: To prepare and optimize the siRNA-nanovectors for efficient siRNA delivery to human tumors in vitro and in vivo; AIM 2: To investigate in vitro anti-tumor activities and the mechanism of action of siRNA-nanovectors in combination with chemo/radiotherapy; AIM 3: To investigate the in vivo therapeutic potential of Bcl-2/Bcl-xL siRNA-nanovectors in nude mouse xenograft models of human cancers with high levels of Bcl-2/Bcl-xL Combining siRNA-based Bcl-2/Bcl-xL molecular therapy with conventional therapy would improve the efficacy and overcome the resistance to current cancer treatment, especially for tumor metastasis, in which Bcl-2/Bcl-xL protein is overexpressed and for which conventional therapy is not very effective. Successfully carried out, our studies will provide proof-of-concept that siRNA can be delivered by the self-assembled nanovectors for tumor-targeted silencing of the genes critical for cancer progression and resistance.

描述(申请人提供)：抗凋亡蛋白Bcl2和Bclxl在许多癌症中过度表达，与肿瘤的发生、发展和对治疗的抵抗有关。Bcl2/Bclxl的分子调控是克服当前肿瘤治疗诱导的细胞凋亡抵抗的一种有前途的策略。由小干扰RNA(SiRNA)产生的序列特异性基因沉默已成为癌症研究的有力工具，并有望成为治疗癌症的新的分子治疗手段。然而，有效和特异地将基于siRNA的治疗药物输送到肿瘤及其转移瘤仍然是一个巨大的挑战。我们开发了一种肿瘤特异的、配体靶向的、自组装的DNA-纳米载体系统，该系统在靶向向人类癌症输送各种基因和反义寡核苷酸方面显示出良好的效率和特异性，而对正常组织的影响有限(美国专利号6,749,863)。我们还设计了针对人类Bcl2和Bclxl的siRNAs，可以有效地击倒Bcl2/Bclxl，导致广泛的癌细胞死亡(美国专利正在申请中)。我们建议使用我们的专利纳米载体系统来开发基于siRNA的治疗方法，用于肿瘤靶向沉默Bcl2/Bclxl。我们将检验两个相互关联的假说：(1)肿瘤靶向递送siRNA将有效地沉默Bcl2/Bclxl，并诱导依赖于Bcl2/Bclxl生存的人癌细胞的凋亡；(2)下调抗凋亡的Bcl2/Bclxl反过来将克服耐药性，恢复肿瘤细胞对化疗/放疗的敏感性。我们的长期目标是开发肿瘤靶向的siRNA纳米载体，作为针对Bcl2/Bclxl过表达的人类肿瘤的新的分子治疗手段。为了验证我们的假设，我们提出了三个特定的目标：目的1：制备和优化siRNA纳米载体，以便在体内外有效地向人肿瘤运送siRNA：目的2：研究siRNA纳米载体的体外抗肿瘤活性及其与放化疗联合作用的机制；目的：探讨Bcl2/Bclxl siRNA纳米载体对高表达Bcl2/Bclxl的裸鼠移植瘤的体内治疗潜力，将基于siRNA的Bcl2/Bclxl分子治疗与常规治疗相结合，以提高疗效并克服对现有肿瘤治疗的耐药性，特别是对Bcl2/Bclxl蛋白高表达且常规治疗效果不佳的肿瘤转移。成功开展后，我们的研究将提供概念证明，即siRNA可以通过自组装的纳米载体传递，用于肿瘤靶向沉默癌症进展和耐药的关键基因。