In the present study, poly(ethylene glycol)-b-poly(ε-caprolactone) micelles loaded with etoposide (ETO) were formulated and further conjugated with pentapeptide Glu-Ile-Leu-Asp-Val (EILDV) to target α4β1 integrin receptor overexpressed on metastatic tumor cell. Using a distinct ratio of carboxyl-terminated poly(ethylene glycol)-block-poly(ε-caprolactone) (HOOC–PEG-b-PCL) to methoxy-poly(ethylene glycol)-block-poly(ε-caprolactone (CH3O–PEG-b-PCL) polymers, we formulated a series of micellar formulations having different surface densities of EILDV and observed optimum cellular uptake of micelles with 10% EILDV surface density by B16F10 cells. The cytotoxicity of EILDV-conjugated micelles was observed close to 1.5-fold higher than plain ETO after 72 h of drug incubation, demonstrating controlled release of drug inside the cell after enhanced intracellular uptake with the ability to selectively target cancer cells. In addition, EILDV-conjugated micelles inhibited the migration of B16F10 cells effectively compared with plain ETO and non-conjugated micellar formulations when cells were treated with equivalent cytotoxic concentration of the drug, i.e., IC25. B16F10 cells treated with EILDV-conjugated micelles showed a significant reduction in the attachment of cells to the substrate-coated plate compared with non-conjugated micellar formulations, implying retention of the biological activity of EILDV after coupling to micelles. Furthermore, the in vivo experimental metastasis assay conducted on C57BL/6 mice demonstrated significant activity of EIDLV-conjugated micelles in the reduction of pulmonary metastatic nodule formation in both pretreatment and post-treatment methods. In conclusion, EIDLV-conjugated micelles showed higher efficacy in the treatment of metastasis and would be a promising approach in the treatment of metastasis.

中文翻译：

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EILDV偶联的，依托泊苷装载的可生物降解的聚合物胶束指向过度表达α4β1整联蛋白的肿瘤转移细胞。

在本研究中，配制负载了依托泊苷（ETO）的聚（乙二醇）-b-聚（ε-己内酯）胶束，并进一步与五肽Glu-Ile-Leu-Asp-Val（EILDV）偶联，以靶向α4β1整联蛋白受体在转移性肿瘤细胞上过表达。使用截然不同的羧基封端的聚（乙二醇）-嵌段-聚（ε-己内酯）（HOOC-PEG-b-PCL）与甲氧基-聚（乙二醇）-嵌段-聚（ε-己内酯（CH3O- PEG-b-PCL）聚合物，我们配制了一系列具有不同EILDV表面密度的胶束制剂，并观察到B16F10细胞可最佳吸收10％EILDV表面密度的胶束，并观察到EILDV缀合的胶束的细胞毒性接近1.5。药物温育72小时后，比普通ETO高出三倍，证明了在细胞内摄取增强后具有选择性靶向癌细胞的能力的药物在细胞内的受控释放。此外，当用等价的细胞毒性浓度的药物（即IC25）处理细胞时，与普通的ETO和非缀合的胶束制剂相比，缀合EILDV的胶束可有效抑制B16F10细胞的迁移。与未缀合的胶束制剂相比，用EILDV缀合的胶束处理的B16F10细胞显示细胞与底物涂层板的附着显着减少，这意味着在与胶束偶联后EILDV的生物学活性得以保留。此外，在C57BL / 6小鼠上进行的体内实验转移试验表明，在预处理和后处理方法中，EIDLV偶联的胶束在减少肺转移性结节形成方面均具有显着活性。总之，EIDLV缀合的胶束在转移治疗中显示出更高的疗效，将成为治疗转移的有前途的方法。