A10-PAMAM/AR-siRNA/Dbait纳米递释系统构建及其对去势抵抗性前列腺癌靶向增敏的实验研究

Hormonal resistance and radiation resistance are bottleneck problems of the treatment of Castration-Resistant Prostate Cancer (CRPC). Researches have proved that androgen receptor (AR) play an important role in the progress of CRPC, therefore the treatment strategy targeting AR is extremely significant. Meanwhile, Dbait with efficiency, non-toxicity and no resistance is an ideal novel radiosensitizer. Based on these researches, we aim to build a double targeting delivery system loading AR-siRNA and Dbait, and targeted modifying PAMAM by A10, the aptamer of PSMA. Our research is carried out with PSMA (a specific antigen on the surface of prostate cancer cells) and AR as entry points, and PAMAM as the carrier, in order to explore the gene therapy and radiosensitization of prostate caner affected by this system at the levels of cells and orthotopic animal models. The innovation of our research is that AR-siRNA was first coupled with Dbait, and there is a better integration of gene targeting therapy, endocrine therapy and targeting sensitization radiotherapy, thereby subtly solving multiple problems of CRPC, such as hormonal resistance, radiation resistance and targeting, which accords with the requirement of comprehensive treatment of cancer.

激素抵抗及辐射抗性是去势抵抗性前列腺癌(CRPC)治疗的瓶颈问题。研究证实AR在CRPC进程中仍发挥关键作用，以AR为靶点是重要的治疗策略；Dbait是新型理想的辐射增敏剂，具有高效、无毒、不耐药等优点。基于此研究成果，我们以前列腺癌细胞表面特异性抗原PSMA及AR为研究切入点，以PAMAM为载体，以A10对PAMAM进行靶向修饰，最终形成荷载AR-siRNA和Dbait的双靶向递释系统，从细胞水平和原位动物模型两个层面，首次研究该递释系统对前列腺癌的靶向基因治疗和辐射增敏作用。本研究首次创新性将AR-siRNA和Dbait相偶联，将基因靶向治疗、内分泌治疗及靶向增敏放疗有机结合起来，巧妙地解决了CRPC的激素抵抗、辐射抗性及靶向性多重问题，符合肿瘤综合治疗的策略。

克服前列腺癌激素抵抗性、提高其放射敏感性和靶向性是提高前列腺癌尤其是去势抵抗性前列腺癌（CRPD）整体疗效的关键。Dbait是新近研发的、理想的放射增敏剂，可靶向性抑制放射损伤后NHEJ的整个通路，具有高效、无毒、不耐药等优点。我们以前列腺癌细胞表面特异性抗原PSMA及AR为研究切入点，以PAMAM为载体，以A10对PAMAM进行靶向修饰，进行Dbait纳米递释系统的合成、表征鉴定及细胞毒性实验，并首次研究该Dbait递释系统对前列腺癌细胞的靶向性和辐射增敏作用。结果显示，成功构建了PAMAM-PEG-A10/Dbait纳米递释系统，通过表征鉴定、细胞毒性实验等发现，PAMAM-PEG-A10/Dbait纳米递释系统对前列腺癌细胞具有良好的靶向识别能力，并且具有较低的细胞毒性。通过Western Blot、RT-PCR、集落形成实验、细胞周期检测、细胞凋亡检测等实验证明AR-shRNA能高效的抑制前列腺癌细胞AR的表达，明显抑制前列腺癌细胞的增殖；新型放射增敏剂Dbait对前列腺癌细胞具有良好的靶向增殖抑制和辐射增敏双重作用。本项目首次研究了新型放射增敏剂Dbait对前列腺癌的靶向辐射增敏作用，为Dbait的推广应用及前列腺癌的靶向辐射增敏提供一定的实验依据。