-
目前, 我国癌症的发病率和病死率仍在不断攀升, 放疗仍然在临床肿瘤治疗中占据着不可替代的重要地位[1]。然而, 常规的放疗对患者的辐射面积较大, 并且用于穿透人体组织所需的放射性剂量较高, 因此对人体的正常组织会造成很大的非特异性辐射损伤[2-4]。现阶段, 基于125I的放射性粒子植入治疗技术被广泛应用于乳腺癌、皮肤癌、前列腺癌和宫颈癌等癌症的治疗, 即通过影像引导将密封载体中的放射性核素粒子(简称为放射籽源)穿刺植入到肿瘤组织内, 利用其释放的低能量γ射线杀死肿瘤细胞, 从而达到治疗癌症的目的[5-6]。虽然此手段在临床肿瘤治疗中取得了良好的效果, 并且不良反应较小, 但是125I放射籽源为钛合金外壳, 植入后不能被人体吸收, 同时植入部位可有短时烧灼感, 不利于后续的再次植入治疗。因此, 本实验利用具有渗透性的、能够原位注射的温敏水凝胶(PECT-RGD凝胶, 其中, PECT为含环醚侧基聚己内酯-聚乙二醇三嵌段共聚物; RGD为含有精氨酸-甘氨酸-天冬氨酸的短肽)为基础, 通过物理作用将131I标记的透明质酸[131I-HA-API, 其中, HA为透明质酸, API为1-(3-氨丙基)咪唑]负载到PECT-RGD凝胶中, 形成的新型放疗制剂能够原位注射到肿瘤组织, 形成凝胶制剂后能够实现对肿瘤组织的持久的特异性放疗; 简便、快捷的注射及良好的成胶特性一方面解决了植入时所带来的不便, 另一方面能够使131I长时间稳定在凝胶内, 不会因凝胶快速降解导致131I扩散至非肿瘤组织, 进而避免其对正常组织带来不良作用。
新型渗透性水凝胶作为载体用于肿瘤的放射性核素植入治疗
New permeable hydrogel for tumor radiotherapy in situ
-
摘要:
目的设计并合成一类新型的渗透性水凝胶,通过物理作用负载放疗剂,用于肿瘤的植入治疗。 方法通过酯化反应合成聚合物PECT-RGD(其中,PECT为含环醚侧基聚己内酯-聚乙二醇三嵌段共聚物;RGD为含有精氨酸-甘氨酸-天冬氨酸的短肽),通过酰胺化反应和氯胺T法制备131I标记的透明质酸,核磁共振氢谱(1H-NMR)对其化学结构进行表征;沉淀离心纯化法对标记的透明质酸进行分离纯化;小瓶翻转法验证凝胶的形成;MTT法研究聚合物材料的细胞毒性;利用放射性小动物活体成像系统研究小鼠体内植入的凝胶的体内稳定性及降解情况;通过抑制肿瘤生长体积和肿瘤组织切片研究131I@PECT-RGD凝胶的体内抗肿瘤效率。 结果聚合物PECT-RGD没有细胞毒性;在正常生理体温(37℃)下能够形成稳定的凝胶,并且可以在体内发生自降解;与PBS组相比,注射131I@PECT-RGD凝胶组和131I@PECT凝胶组均呈现较高的抗肿瘤效率,与PBS组比较差异有统计学意义(F=71.968,P < 0.05);131I@PECT-RGD凝胶组与131I@PECT凝胶组比较,抗肿瘤效率之间的差异也具有统计学意义(t=7.276,P < 0.05);3组小鼠体重差异无统计学意义(F=3.878,P > 0.05);HE染色结果显示,注射PBS组的肿瘤组织仅出现小部分坏死,注射131I@PECT凝胶组的肿瘤组织大部分坏死,注射131I@PECT-RGD凝胶组的肿瘤组织基本坏死。 结论131I@PECT-RGD凝胶能够原位注射到肿瘤组织,具有良好的生物相容性、自降解性和抗肿瘤效果,是一种非常有应用前景的肿瘤局部放疗方法。 Abstract:ObjectiveTo design and synthesize a novel permeable hydrogel loaded with a radiation agent for the implantation radiotherapy of tumors. MethodsThe polymer PECT-RGD[PECT:poly(ε-caprolactone-co-1, 4, 8-trioxa[4.6]spiro-9-undecanone)-poly(ethylene glycol)-poly(ε-caprolactone-co-1, 4, 8-trioxa[4.6]spiro-9-undecanone); RGD:Arg-Gly-Asp] was synthesized by esterification reaction, and an 131I-labeled hyaluronic acid was prepared by amidation reaction and chloramine-T method. The chemical structure of them was characterized by 1H-NMR, and the 131I-labeled hyaluronic acid was isolated and purified by precipitation and centrifugation. Hydrogel formation was verified by vial flipping experiment, and the cytotoxicity of the polymer materials was evaluated by MTT assay. The in vivo stability and degradation of the injected hydrogel were studied using a radioactive small animal live imaging system. The in vivo antitumor effect of the 131I@PECT-RGD hydrogel was investigated by inhibiting tumor growth volume and tumor tissue section. ResultsThe polymer PECT-RGD was non-cytotoxic and could form a stable hydrogel under the normal physiological temperature(37℃). This hydrogel is capable of self-degradation in vivo. Compared with the PBS group, the 131I@PECT-RGD hydrogel and the 131I@PECT gel showed significantly higher anti-tumor efficiency (P < 0.05, F=71.968). A significant difference in anti-tumor efficiency was found between the 131I@PECT and 131I@PECT-RGD hydrogels (P < 0.05, t=7.276). No significant difference in body weight was found among the three groups (P > 0.05, F=3.878). HE staining showed that only a small part of the tumor tissue was necrotic in the PBS group, whereas a large part of the tumor tissue was necrotic in the 131I@PECT group; the tumor tissue of the 131I@PECT-RGD group was generally necrotic. ConclusionsThe 131I@PECT-RGD hydrogel could be injected into tumor tissue in situ and display great biocompatibility, self-degradation ability, and anti-tumor activity. Thus, this hydrogel has potential applications in local radiotherapy. -
Key words:
- Neoplasms /
- Hydrogel /
- Radioisotopes /
- Brachytherapy
-
-
[1] De MO, Vakaet LL, De GT, et al. Radiotherapy of prostate cancer with or without intensity modulated beams:a planning comparison[J]. Int J Radiat Oncol Biol Phys, 2000, 47(3):639-648. doi: 10.1016/S0360-3016(00)00419-3 [2] Moding EJ, Kastan MB, Kirsch DG. Strategies for optimizing the response of cancer and normal tissues to radiation[J]. Nat Rev Drug Discov, 2013, 12(7):526-542. DOI:10.1038/nrd4003. [3] Bentzen SM. Preventing or reducing late side effects of radiation therapy:radiobiology meets molecular pathology[J]. Nat Rev Cancer, 2006, 6(9):702-713. doi: 10.1038/nrc1950 [4] 李功祥, 李险峰.放化疗相关性肺损伤的研究进展[J].国际放射医学核医学杂志, 2010, 34(4):237-241. DOI:10.3760/cma.j.issn.
1673-4114. 2010. 04. 013. Li GX, Li XF. Proress research on of chemoradiotherapy-ralated lung injury[J]. Int J Radiat Med Nucl Med, 2010, 34(4):237-241. doi: 10.3760/cma.j.issn[5] 张淼. 新型碘125籽源核芯的设计与制备研究[D]. 合肥: 中国科学技术大学, 2016: 6-16.
Zhang M. Design and fabrication of new 125I brachytherapy source[D]. Hefei:University of Science and Technology of China, 2016:6-16.[6] 朱晓珉, 方文岩, 陈军, 等. CT导向下125I粒子植入治疗难治生肺癌的疗效观察[J].国际放射医学核医学杂志, 2011, 35(2):114-117. DOI:10.3760/cma.j.issn.
1673-4114. 2011. 02. 012. Zhu XM, Fang WY, Chen J, et al. CT guided interstitial 125I seed implantation treatment of refractory lung cancer[J]. Int J Radiat Med Nucl Med, 2011, 35(2):114-117. doi: 10.3760/cma.j.issn[7] Zhang Y, Yang C, Wang W, et al. Co-delivery of doxorubicin and curcumin by pH-sensitive prodrug nanoparticle for combination therapy of cancer[J/OL]. Sci Rep, 2016, 6:21225[2017-01-19]. https://www.ncbi.nlm.nih.gov/pubmed/26876480. DOI:10.1038/srep21225. [8] Wang W, Deng L, Liu S, et al. Adjustable degradation and drug release of a thermosensitive hydrogel based on a pendant cyclic ether modified poly(ε-caprolactone) and poly(ethylene glycol) co-polymer[J]. Acta Biomater, 2012, 8(11):3963-3973. DOI:10. 1016/j.actbio.2012.07.021. [9] Huang P, Zhang Y, Wang W, et al. Co-delivery of doxorubicin and 131I by thermosensitive micellar-hydrogel for enhanced in situ synergetic chemoradiotherapy[J]. J Control Release, 2015, 220(Pt A):456-464. DOI:10.1016/j.jconrel.2015.11.007. [10] Wang WW, Deng LD, Xu SX, et al. A reconstituted "two into one" thermosensitive hydrogel system assembled by drug-loaded amphiphilic copolymer nanoparticles for the local delivery of paclitaxel[J]. J Mater Chem B, 2013, 1(4):552-563. DOI:10.1039/c2tb00068g. [11] Dhar S, Gu FX, Langer R, et al. Targeted delivery of cisplatin to prostate cancer cells by aptamer functionalized Pt(Ⅳ) prodrug-PLGA-PEG nanoparticles[J]. Proc Natl Acad Sci U S A, 2008, 105(45):17356-17361. DOI:10.1073/pnas.0809154105. [12] Wu J, Zheng Z, Li G, et al. Control of silk microsphere formation using polyethylene glycol(PEG)[J/OL]. Acta Biomater, 2016, 39:156-168[2017-01-19]. http://www.sciencedirect.com/science/article/pii/S1742706116302379. DOI:10.1016/j.actbio.2016.05.019. [13] Gong C, Shi S, Dong P, et al. Synthesis and characterization of PEG-PCL-PEG thermosensitive hydrogel[J]. Int J Pharm, 2009, 365(1/2):89-99. DOI:10.1016/j.ijpharm.2008.08.027. [14] Liu J, Deng H, Liu Q, et al. Integrin-targeted pH-responsive micelles for enhanced efficiency of anticancer treatment in vitro and in vivo[J]. Nanoscale, 2015, 7(10):4451-4460. DOI:10.1039/c4nr07435a.