Llama-derived Single Variable Domains (Nanobodies) Directed against Chemokine Receptor CXCR7 Reduce Head and Neck Cancer Cell Growth in Vivo
Llama-derived Single Variable Domains (Nanobodies) Directed against Chemokine Receptor CXCR7 Reduce Head and Neck Cancer Cell Growth in Vivo
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DOI：
10.1074/jbc.m113.498436
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发表时间：
2013-10-11
影响因子：
4.8
通讯作者：
Smit, Martine J.
中科院分区：
文献类型：
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作者：
Maussang, David;Mujic-Delic, Azra;Smit, Martine J.
趋化因子受体CXCR 7属于膜结合G蛋白偶联受体超家族，在几种肿瘤类型中表达。用小分子或小干扰（si）RNA抑制CXCR 7已经在几种肿瘤模型中显示出有希望的治疗益处。随着抑制膜结合受体的生物制剂的兴趣和有效性的增加，我们利用“纳米抗体平台”靶向CXCR 7。以前，我们表明，纳米抗体，即来自天然存在的重链骆驼抗体的免疫球蛋白单可变结构域，代表了新的生物工具，以有效地解决困难的药物靶标，如G蛋白偶联受体。在这项研究中，我们开发并表征了针对CXCR 7的高度选择性和有效的纳米抗体。有趣的是，CXCR 7靶向纳米抗体显示出与先前报道的CXCR 7靶向剂相反的拮抗性质。几种高亲和力CXCR 7特异性纳米抗体在体外有效抑制CXCL 12诱导的β-抑制蛋白2募集。对各种肿瘤活检进行了分析，首次显示CXCR 7在头颈部癌中高表达。在裸鼠中使用患者来源的表达CXCR 7的头颈癌异种移植物模型，通过靶向CXCR 7的纳米抗体疗法抑制肿瘤生长。从机制上讲，靶向CXCR 7的纳米抗体不抑制细胞周期进展，而是在体外减少头颈癌细胞的血管生成趋化因子CXCL 1的分泌，因此在此充当反向激动剂，并随后在体内发生血管生成。因此，通过这类新型CXCR 7抑制剂，我们进一步证实了靶向CXCR 7在头颈癌中的治疗相关性。
The chemokine receptor CXCR7, belonging to the membrane-bound G protein-coupled receptor superfamily, is expressed in several tumor types. Inhibition of CXCR7 with either small molecules or small interference (si) RNA has shown promising therapeutic benefits in several tumor models. With the increased interest and effectiveness of biologicals inhibiting membrane-bound receptors we made use of the "Nanobody platform" to target CXCR7. Previously we showed that Nanobodies, i.e. immunoglobulin single variable domains derived from naturally occurring heavy chain-only camelids antibodies, represent new biological tools to efficiently tackle difficult drug targets such as G protein-coupled receptors. In this study we developed and characterized highly selective and potent Nanobodies against CXCR7. Interestingly, the CXCR7-targeting Nanobodies displayed antagonistic properties in contrast with previously reported CXCR7-targeting agents. Several high affinity CXCR7-specific Nanobodies potently inhibited CXCL12-induced beta-arrestin2 recruitment in vitro. A wide variety of tumor biopsies was profiled, showing for the first time high expression of CXCR7 in head and neck cancer. Using a patient-derived CXCR7-expressing head and neck cancer xenograft model in nude mice, tumor growth was inhibited by CXCR7-targeting Nanobody therapy. Mechanistically, CXCR7-targeting Nanobodies did not inhibit cell cycle progression but instead reduced secretion of the angiogenic chemokine CXCL1 from head and neck cancer cells in vitro, thus acting here as inverse agonists, and subsequent angiogenesis in vivo. Hence, with this novel class of CXCR7 inhibitors, we further substantiate the therapeutic relevance of targeting CXCR7 in head and neck cancer.