载 RIPL 肽的纳米结构脂质载体增强了对组织蛋白酶表达癌细胞的细胞内药物递送。

BACKGROUND: To facilitate selective and enhanced drug delivery to hepsin (Hpn)-expressing cancer cells, RIPL peptide (IPLVVPLRRRRRRRRC, 16-mer)-conjugated nanostructured lipid carriers (RIPL-NLCs) were developed. METHODS: NLCs were prepared using a solvent emulsification-evaporation method and the RIPL peptide was conjugated to the maleimide-derivatized NLCs via the thiol-maleimide reaction. Employing a fluorescent probe (DiI), in vitro target-selective intracellular uptake behaviors were observed using fluorescence microscopy and flow cytometry. Separately, docetaxel (DTX) was encapsulated by pre-loading technique, then cytotoxicity and drug release were evaluated. In vivo antitumor efficacy was investigated in BALB/c nude mice with SKOV3 cell tumors after intratumoral injections of different DTX formulations at a dose equivalent to 10 mg/kg DTX. RESULTS: RIPL-NLCs showed positively charged nanodispersion, whereas NLCs were negatively charged. DTX was successfully encapsulated with an encapsulation efficiency and drug loading capacity of 95-98% and 44-46 µg/mg, respectively. DTX release was diffusion-controlled, revealing the best fit to the Higuchi equation. Cellular uptake of DiI-loaded RIPL-NLCs was 8.3- and 6.2-fold higher than that of DiI-loaded NLCs, in Hpn(+) SKOV3 and LNCaP cells, respectively. The translocation of RIPL-NLCs into SKOV3 cells was time-dependent with internalization within 1 h and distribution throughout the cytoplasm after 2 h. DTX-loaded RIPL-NLCs (DTX-RIPL-NLCs) revealed dose-dependent in vitro cytotoxicity, while drug-free formulations were non-cytotoxic. In SKOV3-bearing xenograft mouse model, DTX-RIPL-NLCs significantly inhibited tumor growth: the inhibition ratios of the DTX solution-treated and DTX-RIPL-NLC-treated groups were 61.4% and 91.2%, respectively, compared to those of the saline-treated group (control). CONCLUSION: RIPL-NLCs are good candidates for Hpn-selective drug targeting with a high loading capacity of hydrophobic drug molecules.

背景：为了实现对 Hpn 表达的癌细胞的选择性和增强的药物传递，开发了 RIPL 肽（IPLVVPLRRRRRRRRC，16 肽）-缀合的纳米结构脂质载体（RIPL-NLC）。

方法：采用溶剂乳化-蒸发法制备 NLC，并通过巯基-马来酰亚胺反应将 RIPL 肽偶联到马来酰亚胺衍生的 NLC 上。使用荧光探针（DiI），通过荧光显微镜和流式细胞术观察体外靶向选择性细胞内摄取行为。另外，通过预加载技术包封多西紫杉醇（DTX），然后评估细胞毒性和药物释放。在荷 SKOV3 细胞肿瘤的 BALB/c 裸鼠中，通过肿瘤内注射不同剂量相当于 10mg/kg DTX 的 DTX 制剂，研究体内抗肿瘤疗效。

结果：RIPL-NLC 呈正电荷纳米分散体，而 NLC 呈负电荷。成功包封了 DTX，包封效率和载药量分别为 95-98%和 44-46μg/mg。DTX 释放为扩散控制，最符合 Higuchi 方程。DiI 负载的 RIPL-NLC 的细胞摄取量分别比 DiI 负载的 NLC 在 Hpn(+) SKOV3 和 LNCaP 细胞中高 8.3 倍和 6.2 倍。RIPL-NLC 进入 SKOV3 细胞的转位是时间依赖性的，在 1 小时内内化，在 2 小时后分布在细胞质中。载 DTX 的 RIPL-NLC（DTX-RIPL-NLC）在体外具有剂量依赖性的细胞毒性，而无药物制剂则无细胞毒性。在荷 SKOV3 移植瘤小鼠模型中，DTX-RIPL-NLC 显著抑制肿瘤生长：与生理盐水处理组（对照组）相比，DTX 溶液处理组和 DTX-RIPL-NLC 处理组的抑制率分别为 61.4%和 91.2%。

结论：RIPL-NLC 是 Hpn 选择性药物靶向的良好候选物，具有高负载疏水性药物分子的能力。