偶联双基因靶点的多功能纳米金对基底样乳腺癌的放射增敏研究

Basal like breast cancer is one of the poor prognosis of breast cancer subtype, radioresistance is one of the major reasons for treatment failure. It has been found that multiple oncogenes and/or supressors involved in the regulation of cellular radiosensitivity and metastasis, therefore, targetting multiple pathways is under investigation, but the limit use of the new strategy in the clinic is due to the side-effect, it is imperative that development of new technology and strategy for the improvement of cancer management. nanotechnology has been extensively applied in the medicine, especially gold nanoparticle, therefore, gold-based nanotechnology could be served as either target agent vector or radiosensitizer and offer a new modality to treat cancer..Our Preliminary studies found that co-targeted therapy could synergistically enhance radiosensitivity in basal like breast cancer，additionally, RGD-GNR could downregulate the expression of αvβ3 and enhance the radiosensitivity in A375 cells. Based on the preliminary results, we used basal like breast cancer cell lines for the study and aim to investigate:.1) the relative genes will impact the radiosensitivity of the cells..2) whether multiple target-conjugated gold nanoparticle could enhance the radiosensitivity .3) whether gold nanoparticles could be used as either agent transport vector or novel, low toxic and effective radiosensitivizer. .The significance of the proposed studies are to promote and translate nanotechnology-based cancer treatment from the bench to the clinic.

基底样乳腺癌是乳腺癌中预后较差的亚型之一，放射抵抗是治疗失败的原因之一，近年来研究发现多基因异常与基底样乳腺癌放射抵抗与远处转移密切相关，因此，多靶点阻断治疗是乳腺癌治疗研究的热点，但由于毒副作用成为靶向药物临床应用的瓶颈, 随着纳米技术在肿瘤医学应用的快速发展，为肿瘤分子靶向治疗提供了新的模式。.本项目的前期工作提示多靶点阻断（EGFR和 PI3K）可协同增加基底样乳腺癌细胞的放射敏感性。同时，发现偶联RGD序列（靶向αvβ3）的纳米金可增加肿瘤细胞放射敏感性。因此，本课题在大量前期工作基础上，采用偶联多基因靶点（EGFR和αvβ3）的纳米金，研究其对基底样乳腺癌放射增敏作用及其机制，探索影响基底样乳腺癌细胞放射敏感性的相关靶点，为临床综合治疗的开展提供理论依据，同时探索基于偶联多靶标的纳米金作为一种新型、有效、低毒性的放射增敏材料提供可靠证据，为纳米技术的临床转化研究奠定基础。

基底样乳腺癌是乳腺癌中预后较差的一种亚型，放射抵抗是治疗失败的主要原因之一。近年来研究发现多靶点基因与基底样乳腺癌放射抵抗和远处转移密切相关。我们成功构建具有靶向作用的偶联双基因靶标的多功能金纳米探针，由于此金纳米探针系国内首次报道合成，所以我们申请了发明专利（纳米金属颗粒的制备方法和纳米探针的制备方法。发明人：傅深，赵宁，李冰馨，叶坚。专利号：201610193087.8）。研究发现多功能金纳米探针具有较好的生物相容性和靶向性。在一定浓度范围内金纳米探针对正常细胞的抑制率较低，没有明显的细胞毒性。体内、外实验表明乳腺癌细胞对偶联RGD的金纳米探针的摄取量是未偶联RGD探针的4.63倍，肿瘤组织对偶联RGD的金纳米探针的摄取量是未偶联RGD探针的2.28倍，说明偶联RGD的多功能金纳米探针可以更好地靶向肿瘤细胞。多功能金纳米探针具有放射增敏作用。体外实验表明多功能金纳米探针的放射增敏比SERD0=1.68,高于单纯金纳米探针SERD0=1.29，增敏机制可能与该探针可增加对放射敏感的G2/M期细胞比例、细胞凋亡率和细胞内ROS的产生水平有关；体内实验也表明该探针可明显抑制肿瘤生长，具有较好的体内抗肿瘤活性。此外，我们发现由四个lnRNA组成的基因标签可用于预测乳腺癌预后，未来结合更多病例乃至前瞻性临床试验可用来指导方案决策。体外实验研究发现金纳米探针联合光热治疗对乳腺癌具有放射增敏作用，放射增敏比为1.41，增敏机制与其可以增加细胞凋亡率，降低放射抵抗的S期比例相关。