Sarangthem Vijaya, Cho Eun A, Bae Sang Mun, Singh Thoudam Debraj, Kim Sun-Ji, Kim Soyoun, Jeon Won Bae, Lee Byung-Heon, Park Rang-Woon
Department of Biochemistry and Cell Biology, Cell & Matrix Research Institute, Kyungpook National University, School of Medicine, Daegu, Republic of Korea.
PLoS One. 2013 Dec 10;8(12):e81891. doi: 10.1371/journal.pone.0081891. eCollection 2013.
Various human solid tumors highly express IL-4 receptors which amplify the expression of some of anti-apoptotic proteins, preventing drug-induced cancer cell death. Thus, IL-4 receptor targeted drug delivery can possibly increase the therapeutic efficacy in cancer treatment. Macromolecular carriers with multivalent targeting moieties offered great advantages in cancer therapy as they not only increase the plasma half-life of the drug but also allow delivery of therapeutic drugs to the cancer cells with higher specificity, minimizing the deleterious effects of the drug on normal cells. In this study we designed a library of elastin like polypeptide (ELP) polymers containing tumor targeting AP1 peptide using recursive directional ligation method. AP1 was previously discovered as an atherosclerotic plaque and breast tumor tissue homing peptide using phage display screening method, and it can selectively bind to the interleukin 4 receptor (IL-4R). The fluorescently labeled [AP1-V12]6, an ELP polymer containing six AP1 enhanced tumor-specific targeting ability and uptake efficiency in H226 and MDA-MB-231 cancer cell lines in vitro. Surface plasmon resonance analysis showed that multivalent presentation of the targeting ligand in the ELP polymer increased the binding affinity towards IL-4 receptor compared to free peptide. The binding of [AP1-V12]6 to cancer cells was remarkably reduced when IL-4 receptors were blocked by antibody against IL-4 receptor further confirmed its binding. Importantly, the Cy5.5-labeled [AP1-V12]6 demonstrated excellent homing and longer retention in tumor tissues in MDA-MB-231 xenograft mouse model. Immunohistological studies of tumor tissues further validated the targeting efficiency of [AP1-V12]6 to tumor tissue. These results indicate that designed [AP1-V12]6 can serve as a novel carrier for selective delivery of therapeutic drugs to tumors.
多种人类实体瘤高表达白细胞介素-4受体，该受体可增强某些抗凋亡蛋白的表达，从而阻止药物诱导的癌细胞死亡。因此，靶向白细胞介素-4受体的药物递送可能会提高癌症治疗的疗效。具有多价靶向部分的大分子载体在癌症治疗中具有很大优势，因为它们不仅能延长药物在血浆中的半衰期，还能使治疗药物更特异地递送至癌细胞，将药物对正常细胞的有害影响降至最低。在本研究中，我们使用递归定向连接法设计了一个包含肿瘤靶向AP1肽的类弹性蛋白多肽（ELP）聚合物文库。AP1先前通过噬菌体展示筛选法被发现为动脉粥样硬化斑块和乳腺肿瘤组织归巢肽，它能选择性结合白细胞介素4受体（IL-4R）。荧光标记的[AP1-V12]6，一种含有六个AP1的ELP聚合物，在体外对H226和MDA-MB-231癌细胞系具有增强的肿瘤特异性靶向能力和摄取效率。表面等离子体共振分析表明，与游离肽相比，ELP聚合物中靶向配体的多价呈现增加了对白细胞介素-4受体的结合亲和力。当用抗白细胞介素-4受体抗体阻断白细胞介素-4受体时，[AP1-V12]6与癌细胞的结合显著减少，进一步证实了其结合作用。重要的是，Cy5.5标记的[AP1-V12]6在MDA-MB-231异种移植小鼠模型的肿瘤组织中表现出优异的归巢能力和更长的滞留时间。肿瘤组织的免疫组织学研究进一步验证了[AP1-V12]6对肿瘤组织的靶向效率。这些结果表明，设计的[AP1-V12]6可作为一种新型载体，用于将治疗药物选择性递送至肿瘤。
