Targeting malignant B cells with an immunotoxin against ROR1.
Targeting malignant B cells with an immunotoxin against ROR1.
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作者：
Baskar S;Wiestner A;Wilson WH;Pastan I;Rader C
受体酪氨酸激酶样孤儿受体 1 (ROR1) 在慢性淋巴细胞白血病 (CLL) 和套细胞淋巴瘤 (MCL) 中的选择性细胞表面表达，使 ROR1 成为治疗性单克隆抗体 (mAb) 的新型且有前景的靶标。通过杂交瘤技术产生的四种小鼠单克隆抗体表现出与人 ROR1 的特异性结合。表位作图研究表明，两种 mAb（2A2 和 2D11）识别 ROR1 胞外区域的 N 端表位，另外两种（1A1 和 1A7）识别 C 端表位。重组制备了由截短的假单胞菌外毒素 A (PE38) 和 2A2-IgG 的 VH 和 VL 片段组成的 ROR1-免疫毒素 (BT-1)。 2A2-IgG 和 BT-1 均表现出与原代 CLL 和 MCL 细胞以及 MCL 细胞系的剂量依赖性和选择性结合。动力学分析显示与 hROR1 的亲和力/亲和力为 0.12 nM (2A2-IgG) 至 65 nM (BT-1)，分别描述了二价和单价相互作用。与细胞表面 ROR1 结合后，2A2-IgG 和 BT-1 被原代 CLL 细胞和 MCL 细胞系部分内化，并且 BT-1 在体外诱导表达 ROR1 的 MCL 细胞系深度凋亡（EC50 = 16 pM–16 nM），但不影响 ROR1 阴性细胞系。我们的数据表明，ROR1 免疫毒素（例如 BT-1）可以作为表达 ROR1 的 B 细胞恶性肿瘤和其他癌症的靶向治疗剂。
The selective cell surface expression of receptor tyrosine kinase-like orphan receptor 1 (ROR1) in chronic lymphocytic leukemia (CLL) and mantle cell lymphoma (MCL) has made ROR1 a novel and promising target for therapeutic monoclonal antibodies (mAbs). Four mouse mAbs generated by hybridoma technology exhibited specific binding to human ROR1. Epitope mapping studies showed that two mAbs (2A2 and 2D11) recognized N-terminal epitopes in the extracellular region of ROR1 and the other two (1A1 and 1A7) recognized C-terminal epitopes. A ROR1- immunotoxin (BT-1) consisting of truncated Pseudomonas exotoxin A (PE38) and the VH and VL fragments of 2A2-IgG was made recombinantly. Both 2A2-IgG and BT-1 showed dose-dependent and selective binding to primary CLL and MCL cells and MCL cell lines. Kinetic analyses revealed 0.12-nM (2A2-IgG) to 65-nM (BT-1) avidity/affinity to hROR1, depicting bivalent and monovalent interactions, respectively. After binding to cell surface ROR1, 2A2-IgG and BT-1 were partially internalized by primary CLL cells and MCL cell lines, and BT-1 induced profound apoptosis of ROR1-expressing MCL cell lines in vitro (EC50 = 16 pM–16 nM), but did not affect ROR1-negative cell lines. Our data suggest that ROR1-immunotoxins such as BT-1 could serve as targeted therapeutic agents for ROR1-expressing B cell malignancies and other cancers.
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影响因子：
20.3
作者：
Hudecek, Michael;Schmitt, Thomas M.;Riddell, Stanley R.
通讯作者：
Riddell, Stanley R.
影响因子：
20.3
作者：
Bagnara, Davide;Kaufman, Matthew S.;Chiorazzi, Nicholas
通讯作者：
Chiorazzi, Nicholas
影响因子：
20.3
作者：
Dai, CH;Krantz, SB
通讯作者：
Krantz, SB
影响因子：
6.5
作者：
Choudhury, Aniruddha;Derkow, Katja;Mellstedt, Hakan
通讯作者：
Mellstedt, Hakan
DOI：
10.1073/pnas.0712148105
发表时间：
2008-02-26
影响因子：
11.1
作者：
Fukuda, Tetsuya;Chen, Liguang;Kipps, Thomas J.
通讯作者：
Kipps, Thomas J.