CL264

CL264 is a a potent and highly specific toll-like receptor 7 (TLR7) ligand. Immune cells utilize toll-like receptors (TLRs) to sense pathogen associated molecular patterns (PAMPs), which represents the starting point of the innate immune response s^[1].

Using concentrations from 0.5 to 10?μg/mL, stimulation with CL264 resulted in a dose-dependent secretion of TNF-α?after 6 hours. CAL-1 cells were stimulated with CL264 (5?μg/mL) for up to 12 hours. ?CAL-1 cells were seeded into 96-well plates. After overnight resting, cells were stimulated with CL264 or 9.2s RNA or the combination of both. After incubation as indicated, cell supernatant was analyzed for TNF-α, IL-6, and IFN-β?by ELISA. CL264 led to a robust, time-dependent release of TNF-α?reaching absolute levels of 1347?pg/mL TNF-α?into the supernatant^[1].Peripheral blood mononuclear cells (PBMCs) stimulated with CL264, IL-6, IL-8 and IL-12 were significantly stimulated^[2].

The TLR7 agonist CL264 ,40 μg/injectionat day 0, 3 and 6 after tumor grafting, stimulated tumor growth, and this pro-tumorigenic effect was completely lost in the absence of MDSCs, both in WT mice and in TLR7 KO mice. The tumor growth exacerbating effect of TLR7 stimulation is mediated by the increased number of MDSCs within the tumor microenvironment.The secretion of CCL2 and GM-CSF by tumor cells was confirmed in vitro, which was found increased in supernatants of CL264-stimulated cells,these results suggest that CL264 may stimulate the recruitment of MDSCs via the induction of CCL2 and GM-CSF.^[3].

References:
[1].Hilbert T, Steinhagen F, et al. Synergistic Stimulation with Different TLR7 Ligands Modulates Gene Expression Patterns in the Human Plasmacytoid Dendritic Cell Line CAL-1. Mediators Inflamm. 2015;2015:948540.
[2].Dajon M, Iribarren K, et al. Toll like receptor 7 expressed by malignant cells promotes tumor progression and metastasis through the recruitment of myeloid derived suppressor cells. Oncoimmunology. 2018 Oct 11;8(1):e1505174.

CL264 是一种有效且高度特异性的 Toll 样受体 7 (TLR7) 配体。免疫细胞利用 Toll 样受体 (TLR) 感知病原体相关分子模式 (PAMP)，这是先天免疫反应的起点 s^[1]。

使用 0.5 至 10μg/mL 的浓度，用 CL264 刺激会在 6 小时后导致 TNF-α 的剂量依赖性分泌。用 CL264 (5μg/mL) 刺激 CAL-1 细胞长达 12 小时。将 CAL-1 细胞接种到 96 孔板中。过夜休息后，用 CL264 或 9.2s RNA 或两者的组合刺激细胞。如所示孵育后，通过 ELISA 分析细胞上清液中的 TNF-α、IL-6 和 IFN-β。 CL264 导致上清液中 TNF-α 的稳健、时间依赖性释放达到 1347pg/mL TNF-α 的绝对水平^[1]。用 CL264 刺激的外周血单核细胞 (PBMC)， IL-6、IL-8和IL-12均得到显着刺激^[2]。

TLR7 激动剂 CL264，40 μg/ 次注射，在肿瘤移植后的第 0、3 和 6 天，刺激肿瘤生长，并且在没有 MDSCs 的情况下，这种促肿瘤发生作用在 WT 小鼠和 TLR7 KO 小鼠中完全消失. TLR7 刺激的肿瘤生长加剧作用是由肿瘤微环境中 MDSC 数量的增加介导的。体外证实了肿瘤细胞分泌 CCL2 和 GM-CSF，这在 CL264 刺激细胞的上清液中发现增加，这些结果表明，CL264 可能通过诱导 CCL2 和 GM-CSF 刺激 MDSCs 的募集。^[3]。