Division of Pharmacoengineering and Molecular Pharmaceutics and Center for Nanotechnology in Drug Delivery, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
School of Pharmaceutical Sciences, Zhengzhou University, 100 Kexue Avenue, Zhengzhou 450001, China.
Theranostics. 2018 Jun 13;8(14):3781-3796. doi: 10.7150/thno.24821. eCollection 2018.
Tumor-associated fibroblasts (TAFs) play a critical role in the suppressive immune tumor microenvironment (TME), compromising the efficacy of immunotherapy. To overcome this therapeutic hurdle, we developed a nanoemulsion (NE) formulation to deliver fraxinellone (Frax), an anti-fibrotic medicine, to TAFs, as an approach to reverse immunosuppressive TME of desmoplastic melanoma. Frax NE was prepared by an ultrasonic emulsification method. The tumor inhibition effect was evaluated by immunofluorescence staining, masson trichrome staining and western blot analysis. Immune cell populations in tumor and LNs were detected by flow cytometry. This Frax NE, with a particle size of around 145 nm, can efficiently accumulate in the tumor site after systemic administration and was taken up by TAFs and tumor cells. A significant decrease in TAFs and stroma deposition was observed after intravenous administration of Frax NE, and Frax NE treatment also remolded the tumor immune microenvironment, as was reflected by an increase of natural-killer cells, cytotoxic T cells (CTLs) as well as a decrease of regulatory B cells, and myeloid-derived suppressor cells in the TME. In addition, after treatment by Frax NEs, T helper 1 (Th1) cytokines of interferon gamma (IFN-γ), which effectively elicit anti-tumor immunity, were enhanced. Transforming growth factor-β (TGF-β), chemokine (C-C motif) ligand 2 (CCL2) and interleukin 6 (IL6), which inhibit the development of anti-tumor immunity, were reduced. Although Frax NE demonstrated an inhibitory effect on tumor growth, this mono-therapy could only achieve partial antitumor efficacy, and the tumor growth effect was not maintained long-term after dosing stopped. Therefore, a tumor-specific peptide vaccine was combined with Frax NEs. The combination led to enhanced tumor-specific T-cell infiltration, activated death receptors on the tumor cell surface, and induced increased apoptotic tumor cell death. Collectively, Frax NE combined with tumor-specific peptide vaccine might be an effective and safe strategy to remodel fibrotic TME, thereby enhancing immune response activation, resulting in a prolonged efficiency for advanced desmoplastic melanoma.
肿瘤相关成纤维细胞（TAFs）在抑制性肿瘤微环境（TME）中发挥着关键作用，从而降低了免疫疗法的疗效。为了克服这一治疗障碍，我们开发了一种纳米乳液（NE）制剂，将 fraxinellone（Frax）——一种抗纤维化药物，递送到 TAFs 中，以逆转促纤维化黑色素瘤的免疫抑制性 TME。 Frax NE 通过超声乳化法制备。通过免疫荧光染色、马松三色染色和 Western blot 分析评估肿瘤抑制作用。通过流式细胞术检测肿瘤和 LNs 中的免疫细胞群。 这种粒径约为 145nm 的 Frax NE，在全身给药后能够有效地在肿瘤部位积聚，并被 TAFs 和肿瘤细胞摄取。静脉注射 Frax NE 后，观察到 TAFs 和基质沉积明显减少，Frax NE 治疗还重塑了肿瘤免疫微环境，表现为 NK 细胞、细胞毒性 T 细胞（CTL）增加，调节性 B 细胞和髓源抑制细胞减少。此外，Frax NEs 处理后，有效引发抗肿瘤免疫的 Th1 细胞因子干扰素 γ（IFN-γ）增强。抑制抗肿瘤免疫发展的转化生长因子-β（TGF-β）、趋化因子（C-C 基序）配体 2（CCL2）和白细胞介素 6（IL6）减少。尽管 Frax NE 对肿瘤生长表现出抑制作用，但这种单一疗法只能实现部分抗肿瘤疗效，停药后肿瘤生长效果不能长期维持。因此，将肿瘤特异性肽疫苗与 Frax NEs 联合使用。这种联合导致肿瘤特异性 T 细胞浸润增强，激活肿瘤细胞表面的死亡受体，并诱导增加的凋亡肿瘤细胞死亡。 总之，Frax NE 联合肿瘤特异性肽疫苗可能是重塑纤维化 TME 的有效且安全的策略，从而增强免疫反应激活，使晚期促纤维化黑色素瘤的疗效延长。
