Children's Cancer Institute, Lowy Cancer Centre, UNSW Sydney, Kensington, NSW, Australia; School of Women's and Children's Health, UNSW Sydney, Kensington, NSW, Australia.; University of New South Wales Centre for Childhood Cancer Research, UNSW Sydney, Kensington, NSW, Australia; Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Ain Shams University, Cairo, Egypt.
Institute of Biochemistry II, Jena University Hospital, Jena, Germany.
Int J Biol Macromol. 2021 Nov 1;190:214-223. doi: 10.1016/j.ijbiomac.2021.08.194. Epub 2021 Sep 2.
Antibody fragments are promising building blocks for developing targeted therapeutics, thus improving treatment efficacy while minimising off-target toxicity. Despite recent advances in targeted therapeutics, patients with Philadelphia-like acute lymphoblastic leukemia (Ph-like ALL), a high-risk malignancy, lack specific and effective targeted treatments. Cytokine receptor-like factor 2 (CRLF2) is overexpressed in 50% of Ph-like ALL cases, conferring the survival of leukemia blasts through activation of the JAK/STAT signalling pathway. Targeting such a vital cell-surface protein could result in potent anti-leukaemic efficacy and reduce the likelihood of relapse associated with antigen loss. Herein, we developed a novel single-chain variable fragment (scFv) against CRLF2 based on a monoclonal antibody raised against the recombinant extracellular domain of human TSLPRα chain. The scFv fragment demonstrated excellent binding affinity with CRLF2 protein in the nanomolar range. Cellular association studies in vitro using an inducible CRLF2 knockdown cell line and ex vivo using patient-derived xenografts revealed the selective association of the scFv with CRLF2. The fragment exhibited significant receptor antagonistic effects on STAT5 signalling, suggesting possible therapeutic implications in vivo. This study is the first to describe the potential use of a novel scFv for targeting Ph-like ALL.
抗体片段是开发靶向治疗药物的有前途的构建模块，因此可以提高治疗效果，同时最大限度地减少脱靶毒性。尽管靶向治疗最近取得了进展，但费城样急性淋巴细胞白血病（Ph-like ALL）患者缺乏特异性和有效的靶向治疗方法，这种疾病是一种高风险的恶性肿瘤。细胞因子受体样因子 2（CRLF2）在 50%的 Ph-like ALL 病例中过表达，通过激活 JAK/STAT 信号通路赋予白血病细胞存活能力。针对这种重要的细胞表面蛋白可能会产生强大的抗白血病疗效，并降低与抗原丢失相关的复发可能性。在此，我们基于针对人 TSLPRα 链重组细胞外结构域的单克隆抗体，开发了一种针对 CRLF2 的新型单链可变片段（scFv）。scFv 片段在纳摩尔范围内表现出与 CRLF2 蛋白的优异结合亲和力。体外使用可诱导的 CRLF2 敲低细胞系进行细胞结合研究和使用患者来源的异种移植物进行离体研究表明，scFv 与 CRLF2 选择性结合。该片段对 STAT5 信号表现出显著的受体拮抗作用，表明其在体内可能具有治疗意义。这项研究首次描述了一种新型 scFv 在靶向 Ph-like ALL 中的潜在用途。
