Background: Honokiol (HK) is a natural bioactive compound with proven antineoplastic properties against melanoma. However, it shows very low bioavailability when administered orally. Alternatively, topical administration may offer a promising route. The objective of the current study was to fabricate HK transfersomes (HKTs) for topical treatment of melanoma. As an ultradeformable carrier system, transfersomes can overcome the physiological barriers to topical treatment of melanoma: the stratum corneum and the anomalous tumor microenvironment. Moreover, the immunomodulatory and stemness-regulation roles of HKTs were the main interest of this study.
Methods: TFs were prepared using the modified scalable heating method. A three-factor, three-level Box–Behnken design was utilized for the optimization of the process and formulation variables. Intracellular uptake and cytotoxicity of HKTs were evaluated in nonactivated and stromal cell–activated B16F10 melanoma cells to investigate the influence of the complex tumor microenvironment on the efficacy of HK. Finally, ELISA and Western blot were performed to evaluate the expression levels of TGF-β and clusters of differentiation (CD47 and CD133, respectively).
Results: The optimized formula exhibited a mean size of 190 nm, highly negative surface charge, high entrapment efficiency, and sustained release profile. HKTs showed potential to alleviate the immunosuppressive characteristics of B16F10 melanoma in vitro via downregulation of TGF-β signaling. In addition, HKTs reduced expression of the “do not eat me” signal — CD47. Moreover, HKTs possessed additional interesting potential to reduce the expression of the stem-like cell marker CD133. These outcomes were boosted upon combination with metformin, an antihyperglycemic drug recently reported to possess different functions in cancer, while combination with collagenase, an extracellular matrix–depleting enzyme, produced detrimental effects.
Conclusion: HKTs represent a promising scalable formulation for treatment of the aggressive B16F10 melanoma, which is jam-packed with immunosuppressive and stem-like cell markers.



中文翻译：

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绿色合成和厚朴酚转移体可缓解侵袭性 B16F10 黑色素瘤的免疫抑制和干细胞样特征

背景：和厚朴酚 (HK) 是一种天然生物活性化合物，已被证实具有抗黑色素瘤的特性。然而，口服给药时其生物利用度非常低。或者，局部给药可能提供一种有前途的途径。当前研究的目的是制造用于局部治疗黑色素瘤的 HK 传递体 (HKT)。作为一种超变形载体系统，传递体可以克服黑色素瘤局部治疗的生理障碍：角质层和异常的肿瘤微环境。此外，HKT 的免疫调节和干性调节作用是本研究的主要兴趣。
方法：使用改进的可扩展加热方法制备 TF。采用三因素、三水平 Box-Behnken 设计来优化工艺和配方变量。在非激活和基质细胞激活的 B16F10 黑色素瘤细胞中评估 HKT 的细胞内摄取和细胞毒性，以研究复杂的肿瘤微环境对 HK 功效的影响。最后，进行 ELISA 和 Western blot 评估 TGF-β 和分化簇（分别为 CD47 和 CD133）的表达水平。
结果：优化后的配方平均粒径为190 nm，具有高负表面电荷、高包封率和缓释特性。HKT 在体外表现出通过下调 TGF-β 信号传导缓解 B16F10 黑色素瘤免疫抑制特征的潜力。此外，HKT 还减少了“别吃我”信号 CD47 的表达。此外，HKT 还具有降低干细胞样细胞标记物 CD133 表达的额外有趣潜力。与二甲双胍联合使用可以增强这些结果，二甲双胍是一种抗高血糖药物，最近报道在癌症中具有不同的功能，而与胶原酶（一种细胞外基质消耗酶）联合使用会产生有害影响。
结论： HKT 代表了一种有前途的可扩展制剂，用于治疗侵袭性 B16F10 黑色素瘤，这种黑色素瘤充满了免疫抑制和干细胞样细胞标记。