基于组蛋白的DNA靶向功能纳米热化疗制剂的构建及在耐药肿瘤治疗中的应用

Nanomedicines with the function of thermochemotherapy play important roles in the treatment of drug-resistant tumor by simultaneously delivering drugs and depressing the expression of resistance genes through the photothermal effect. However, low treatment efficiency and poor treatment depth are still the problems faced by thermochemotherapeutic nanomedicine in the treatment of drug-resistant tumor. By considering the expression sites of drug resistance gene and the mechanism of most anti-cancer drugs, we intends to construct a histone based nanomedicine by using DNA molecules as target for improving the efficiency of thermochemotherapy of drug-resistant tumor. Histone is a kind of natural protein in human body, can be fabricated outside the nucleus and internalized by nucleus through active transport, thus is a natural carrier for DNA targeting. Herein, based on the biological functions of histone, we using histone as carrier by loading anti-cancer drug doxorubicin and near-infrared dye indocyanine green for constructing a nanomedicine for thermochemotherapy of anti-cancer drugs. Through size control, modification of active ligand and the nuclear localization signal in histone, the nanomedicine can target DNA molecules in resistant cells for implementing thermochemotherapy, can effectively improve the treatment efficiency of drug-resistant tumor.

具有光热/药物协同治疗功能的纳米制剂在耐药肿瘤治疗中具有潜力，可在输送药物的同时通过高温抑制耐药基因表达，从而逆转肿瘤耐药。但是，治疗效率低，治疗深度差是热化疗纳米制剂在耐药肿瘤治疗中存在的问题。为提高热化疗纳米制剂在耐药肿瘤中的治疗效率，本项目从耐药基因表达位点和多数抗癌药物的机制出发，拟构建能靶向DNA分子的组蛋白热化疗纳米制剂。组蛋白是一类碱性蛋白，在细胞核外被加工，通过主动运输的方式进入细胞核，可与DNA结合，是一种天然的DNA靶向载体材料。我们从组蛋白的生物功能特点出发，以组蛋白为载体装载化疗药物阿霉素和近红外染料吲哚菁绿。通过尺度控制、肿瘤细胞靶向分子修饰及组蛋白自身核定位信号的作用，实现从肿瘤细胞膜到核内DNA分子的靶向功能，将热化疗协同治疗精准地作用于核内DNA分子，可有效提升耐药肿瘤治疗效率。

具有光热/药物协同治疗功能的纳米制剂在耐药肿瘤治疗中具有潜力，可在输送药物的同时通过高温抑制耐药基因表达，从而逆转肿瘤耐药。但是，治疗效率低，治疗深度差是热化疗纳米制剂在耐药肿瘤治疗中存在的问题。为提高热化疗纳米制剂在耐药肿瘤中的治疗效率，本项目从耐药基因表达位点和多数抗癌药物的机制出发，利用人源组蛋白构建能进入细胞核的热化疗纳米制剂，将热化疗协同治疗精准地作用于核内，可有效提升耐药肿瘤治疗效率。本项目中，我们利用阿霉素(DOX)、近红外染料IR825和人总组蛋白构建了一种热化疗纳米制剂DIR825@histone。项目研究结果表明，DIR825@histone可通过转胞吞作用穿透肿瘤组织并被肿瘤细胞内化后进入细胞核。DIR825@histone具有较好的光热和药物控释性能。DIR825@histone的化疗细胞毒性明显高于非核靶向DIR825@HSA。由于具有核靶向特性，DIR825@histone显示出更强的光热治疗效果，包括直接破坏细胞核，显著下调P-gp和HSP-90。上述结果表明，靶向耐药肿瘤细胞核的光热治疗可大大提升耐药逆转效率。另外，我们的研究表明，介入激光可以更好地协助DIR825@histone抑制耐药肿瘤。DIR825@histone和介入性激光联合使用可导致耐药肿瘤中P-gp、VEGF、MMP2和MMP9显著下调，说明DIR820@histone介导的核靶向热化疗不仅能有效杀伤耐药细胞，还能显著下调与肿瘤进展相关的基因。因此，DIR820@histone及其介导的核靶向热化疗在耐药肿瘤治疗方面潜力巨大。