石墨烯基纳米药物经导管动脉化疗栓塞治疗原发性肝癌

Transcatheter arterial chemoembolization (TACE) is the first choice of treatment for unresectable hepatocellular carcinoma (HCC). Due to the inherent chemoresistance of liver cancer cells, short retention period of chemotherapeutic agents inside the tumor cells, and poor stability of lipiodol/chemotherapeutic agents emulsion, et.al, incomplete necrosis of cancer cells after TACE treatment ultimately leads to the failure of therapy. With ultra-high surface area, graphene based nanomaterials such as graphene oxide (GO) received widespread attention as vehicle for drug delivery. In our preliminary test we found that GO presented excellent dispersibility in iodized oil, which stably and uniformly dispersed water-soluble chemotherapeutic agent in Lipiodol as a vehicle. In the cell experiments, we found that graphene oxide remarkably enhanced the cytotoxicity effect of chemotherapy agents on tumor cells. Yet, it has been reported and our previous studies [Carbon，2014] and preliminary experiment revealed that GO exerted significant cytotoxicity, limiting its application via conventional route of administration. Based on the preliminary study, by employing in vitro and in vivo models, this project will take the full advantages of GO's capability of vector and cytotoxicity with the method of interventional radiology to further investigate the therapeutic efficacy of doxorubicin-loaded graphene oxide TACE in the treatment of HCC as compared to lipiodol and drug eluting beads, providing new directions to improve the therapeutic effect of TACE.

经导管动脉化疗栓塞术（TACE）是无法切除的肝癌的首选疗法。由于肝癌细胞固有耐药、化疗药在肿瘤细胞内存留时间短、碘油/化疗药乳化剂的不稳定性等原因，TACE术后肝癌细胞坏死不完全，导致治疗失败。具有超高比表面积的石墨烯基纳米材料如氧化石墨烯（graphene oxide，GO）作为药物载体受到广泛的关注。我们在前期试验中发现，GO在碘油中具有极佳的分散性，作为载体能稳定地将水溶性化疗药物均匀分散于碘油中。在细胞实验中，我们发现GO可显著增强化疗药对肿瘤细胞的杀伤作用。然而，文献报道以及我们的前期研究【Carbon，2014】和预实验均发现，GO有明显的细胞毒性，限制了其经常规给药途径的应用。本项目将在前期研究基础上，采用体内外模型，以碘化油和药物洗脱微球为对照，通过介入的方法充分利用GO的载体性和细胞毒性，深入研究GO负载阿霉素在TACE治疗肝癌中的效果，为提高TACE的疗效提供新的思路。

在本项目中，课题组以改良Hummers法制备氧化石墨烯（GO），并以多种方法对GO进行表面修饰，获得了一系列具有不同性质的石墨烯基纳米药物，包括：亲水性的阿霉素负载的叶酸靶向的磷酰胆碱修饰氧化石墨烯（DOX@GO-PCn-FA）、疏水性的阿霉素负载的直链烷基修饰氧化石墨烯（DOX@GO-C18）以及疏水性的丙烯酸-2-羟基乙酯修饰的氧化石墨烯（GO-HEAx）。其中，GO-PCn-FA是一种叶酸靶向的pH响应药物载体，载药量为21％，而GO-C18能在碘油中长期稳定分散。. 随后，课题组建立了兔VX2肝癌动物模型，并以DOX@GO-PCn-FA和DOX@GO-C18在此模型上行化疗栓塞治疗肝癌。术后以动态增强CT扫描、病理学检查以及血清学检查以研究疗效和安全性。结果显示，TACE治疗后肿瘤血供明显减少，生长受明显抑制。病理学检查可见纳米药物主要沉积于肿瘤内，肿瘤坏死明显，主要正常组织未见纳米药物沉积。血清学检查显示术后出现一过性肝酶学异常，在2周内可恢复至正常水平。此外，课题组将GO-HEAx应用于混合树脂的紫外光固化中，结果显示GO-HEAx能显著增强混合树脂的物理性能，拓展了疏水氧化石墨烯的应用范围。课题组进一步研究了石墨烯基纳米药物对免疫细胞，包括巨噬细胞、T细胞和B细胞的影响，未见石墨烯基纳米药物对巨噬细胞的吞噬功能、T细胞和B细胞的活化和功能无不良影响。. 综上所述，本项目深入研究了石墨烯基纳米药物的多种制备方法以及应用于TACE治疗肝癌中的效果和安全性，为提高TACE的疗效提供新的思路。