Faculty of Pharmacy & Pharmaceutical Sciences, University of Alberta, Edmonton, T6G 2N8, Canada.
Mol Pharm. 2010 Apr 5;7(2):364-74. doi: 10.1021/mp900145g.
Constitutively activated signal transducer and activator of transcription-3 (STAT3) in tumor and dendritic cells (DCs) plays a critical role in tumor-induced immunosuppression. This is considered a major challenge in effective immunotherapy of cancer. Herein we describe the development of a polymeric nanocarrier for the delivery of JSI-124 (a small molecule inhibitor of STAT3) to tumor and immunosuppressed DCs using poly(d,l-lactic-co-glycolic acid) nanoparticles (PLGA NPs). For this purpose, JSI-124 was chemically conjugated to PLGA and the PLGA-JSI-124 conjugate was formulated into nanoparticles using the emulsification solvent evaporation method. The attachment of JSI-124 to PLGA was confirmed by a combination of thin layer chromatography and (1)H NMR. The level of JSI-124 in NPs, determined by liquid chromatography-mass spectrometry, was found to be 1.7 +/- 0.3 microg per mg of PLGA. The PLGA-JSI-124 NPs demonstrated a controlled drug release profile over a 1-month period and exhibited potent anticancer and STAT3 inhibitory activity comparable to the soluble JSI-124 after 24 h incubation with B16 melanoma cells, in vitro. Moreover, PLGA-JSI-124 NPs efficiently suppressed the level of p-STAT3 in p-STAT3(high) DCs, generated from mouse bone marrow cells in the presence of conditioned media of B16 cells (B16CM-DCs), and improved their function as assessed by mixed lymphocyte reaction (MLR). Specifically cotreatment of B16CM-DCs with PLGA-JSI-124 NPs and PLGA NPs containing the DC adjuvant CpG resulted in higher levels of T cell proliferation in the MLR assay compared with B16CM-DCs untreated or treated with either CpG NPs or JSI-124 NPs alone. Our results indicate that PLGA NPs containing conjugated JSI-124 can potentially provide a useful platform for sustained JSI-124 release in tumor and its targeted delivery to DCs leading to the modulation of anticancer response by JSI-124 in tumor cells and immunosuppressed DCs, in vitro.
肿瘤和树突状细胞（DC）中组成性激活的信号转导子和转录激活子 3（STAT3）在肿瘤诱导的免疫抑制中起着关键作用。这被认为是癌症有效免疫治疗的主要挑战。在此，我们描述了一种聚合物纳米载体的开发，用于使用聚（D，L-丙交酯-共-乙交酯）纳米粒（PLGA NPs）将 JSI-124（一种 STAT3 的小分子抑制剂）递送至肿瘤和免疫抑制的 DC。为此，通过化学方法将 JSI-124 连接到 PLGA 上，并通过乳化溶剂蒸发法将 PLGA-JSI-124 缀合物制成纳米粒。通过薄层层析和（1）H NMR 的组合证实了 JSI-124 与 PLGA 的连接。通过液相色谱-质谱法测定 NPs 中的 JSI-124 含量为 1.7 +/- 0.3 microg/每毫克 PLGA。PLGA-JSI-124 NPs 在 1 个月的时间内表现出可控的药物释放特性，并在与 B16 黑色素瘤细胞孵育 24 小时后表现出与可溶性 JSI-124 相当的抗肿瘤和 STAT3 抑制活性，体外。此外，PLGA-JSI-124 NPs 能够有效抑制由 B16 细胞条件培养基（B16CM-DCs）生成的 p-STAT3（高）DCs 中的 p-STAT3 水平，并通过混合淋巴细胞反应（MLR）评估改善其功能。具体而言，与 PLGA-JSI-124 NPs 和含有 DC 佐剂 CpG 的 PLGA NPs 共同处理 B16CM-DCs 导致 MLR 测定中 T 细胞增殖水平高于未经处理或单独用 CpG NPs 或 JSI-124 NPs 处理的 B16CM-DCs。我们的结果表明，含有缀合的 JSI-124 的 PLGA NPs 可能为肿瘤中持续释放 JSI-124 并将其靶向递送至 DC 提供有用的平台，从而导致 JSI-124 在肿瘤细胞和免疫抑制的 DC 中调节抗肿瘤反应，体外。
