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

描述（由申请人提供）：在目前资助的R 01的支持下，我们修改和优化了我们的纳米载体，用于肿瘤靶向递送Bcl-2和Bcl-xL特异性siRNA/shRNA。我们意外地发现，我们的纳米载体也靶向胰腺癌干细胞（CSC）并将siRNA/shRNA递送至CSC，抑制CSC自我更新并减少体内癌症干细胞。基于我们令人兴奋的新发现，我们建议，在这个竞争性修订项目中，扩大目前R 01的范围，以进一步开发用于递送靶向癌症干细胞的miRNA治疗剂的纳米载体。这是对NOT-OD-09-058的回应：NIH宣布为竞争性修订申请提供恢复法案资金。我们的长期目标是开发纳米载体-miRNA作为一种新的靶向人类癌症干细胞的分子治疗。这个为期两年的项目的目标是探索我们上述专利的纳米载体系统，用于靶向递送基于miRNA的治疗剂至人胰腺癌干细胞，并评估纳米载体递送的肿瘤抑制剂miR-34在抑制CSC中的治疗潜力。我们将检验两个相互关联的基本假设：（1）自组装纳米载体可以有效地将miR-34递送至胰腺癌干细胞，从而恢复癌症干细胞中miR-34的肿瘤抑制功能;（2）miR-34的恢复将通过同时抑制Bcl-2和Notch来抑制胰腺癌干细胞的自我更新，从而为胰腺癌提供一种潜在的新疗法。为了验证我们的假设，我们提出了两个具体的目标：目的1，制备和表征体外和体内靶向CSC的miRNA-纳米载体;目的2，研究纳米载体-miR-34的抗肿瘤活性和作用机制。我们的长期目标是开发纳米载体-miRNA作为一种新的靶向人类癌症干细胞的分子治疗。成功地进行，我们的研究将提供新的，自组装的miRNA纳米载体，可以将肿瘤抑制因子miR-34递送到胰腺CSC并抑制其自我更新和肿瘤起始。纳米载体-miR-34的肿瘤特异性基于：（1）癌症干细胞具有高水平的TfR和miR-34-Notch/Bcl-2的失调以过度自我更新;（2）基于优选的miR-34递送至CSC和CSC的功能抑制的纳米载体的优化制剂;（3）正常干细胞，尽管也是TfR（+），但没有Bcl-2/Notch的失调，并且不依赖Bcl-2/Notch存活。目前提案的数据将为开发nanovector-miR-34作为人类胰腺癌的新型和更有效的治疗方法提供重要的动力，可能通过调节胰腺癌干细胞。 公共卫生关系：我们的目标是探索我们的专利自组装纳米载体系统，用于靶向递送基于miRNA的治疗剂至人胰腺癌干细胞，并评估纳米载体递送的肿瘤抑制剂miR-34在抑制癌症干细胞中的治疗潜力。成功地进行，我们的研究将提供新的，自组装的miRNA纳米载体，可以将肿瘤抑制因子miR-34传递到胰腺癌干细胞，并抑制其自我更新和肿瘤启动。目前提案的数据将为开发nanovector-miR-34作为靶向癌症干细胞的新型和更有效的人类胰腺癌治疗方法提供重要动力。

DESCRIPTION (provided by applicant): With the support of the current funded R01, we have modified and optimized our nanovectors for tumor targeted delivery of siRNA/shRNA specific to Bcl-2 and Bcl-xL. We found unexpectedly that our nanovectors also targeted to pancreatic cancer stem cells (CSC) and delivered siRNA/shRNA to CSC, inhibited CSC selfrenewal and reduced cancer stem cells in vivo. Based on our exciting new discovery, we propose, in this Competitive Revision project, to expand the scope of the current R01 to further develop the nanovectors for delivery of miRNA-therapeutics targeting cancer stem cells. This is in response to the NOT-OD-09-058: NIH Announces the Availability of Recovery Act Funds for Competitive Revision Applications. Our long-term goal is to develop nanovector-miRNA as a novel molecular therapy targeting human cancer stem cells. The objective in this two-year project is to explore our above patented nanovector system for targeted delivery of miRNA-based therapeutics to human pancreatic cancer stem cells, and to evaluate the therapeutic potential of the nanovector-delivered tumor suppressor miR-34 in inhibiting CSC. We will test two inter-related basic hypotheses: (1) the self-assembled nanovectors can efficiently deliver miR-34 to the pancreatic cancer stem cells, thus restoring the miR-34 tumor suppressor function in cancer stem cells; (2) miR-34 restoration will inhibit the self-renewal of pancreatic cancer stem cells by simultaneously inhibiting Bcl-2 and Notch, and thus provide a potential novel therapy for pancreatic cancer. To test our hypothesis, we propose to carry out two SPECIFIC AIMS: AIM 1, To prepare and characterize the miRNA-nanovectors targeting CSC in vitro and in vivo; AIM 2, To investigate the anti-tumor activities and the mechanism of action of nanovector-miR-34. Our long-term goal is to develop nanovector-miRNA as a novel molecular therapy targeting human cancer stem cells. Successfully carried out, our studies will provide novel, self-assembled miRNA-nanovectors that can deliver tumor suppressor miR-34 to pancreatic CSC and inhibit their self-renewal and tumor-initiation. The tumor specificity of nanovector-miR-34 is based upon: (1) cancer stem cells have high level of TfR and dysregulation of miR-34-Notch/Bcl-2 for excessive self-renewal; (2) the optimized formulation of nanovectors based on preferred miR-34 delivery to and functional inhibition of CSC; (3) normal stem cells, although also TfR(+), have no dysregulation of Bcl-2/Notch and do not rely on Bcl-2/Notch for survival. The data from the current proposal will provide important impetus to develop the nanovector-miR-34 as a novel and more effective therapy for human pancreatic cancer, potentially by modulating pancreatic cancer stem cells. PUBLIC HEALTH RELAVANCE: Our objective is to explore our patented self-assembled nanovector system for targeted delivery of miRNA-based therapeutics to human pancreatic cancer stem cells, and to evaluate the therapeutic potential of the nanovector-delivered tumor suppressor miR-34 in inhibiting cancer stem cells. Successfully carried out, our studies will provide novel, self-assembled miRNA-nanovectors that can deliver tumor suppressor miR-34 to pancreatic cancer stem cells and inhibit their self-renewal and tumor-initiation. The data from the current proposal will provide important impetus to develop the nanovector-miR-34 as a novel and more effective therapy for human pancreatic cancer by targeting cancer stem cells.