Department of Anesthesia, University of California at San Francisco, San Francisco, California 94110, USA.
Mol Cancer Ther. 2010 Jul;9(7):2131-41. doi: 10.1158/1535-7163.MCT-09-1059. Epub 2010 Jun 29.
Glioblastoma multiforme (GBM) is the most common and aggressive form of primary brain tumor for which there is no curative treatment to date. Resistance to conventional therapies and tumor recurrence pose major challenges to treatment and management of this disease, and therefore new therapeutic strategies need to be developed. Previous studies by other investigators have shown that a subpopulation of GBM cells can grow as neurosphere-like cells when cultured in restrictive medium and exhibits enhanced tumor-initiating ability and resistance to therapy. We report here the identification of internalizing human single-chain antibodies (scFv) targeting GBM tumor sphere cells. We selected a large naive phage antibody display library on the glycosylation-dependent CD133 epitope-positive subpopulation of GBM cells grown as tumor spheres and identified internalizing scFvs that target tumor sphere cells broadly, as well as scFvs that target the CD133-positive subpopulation. These scFvs were found to be efficiently internalized by GBM tumor sphere cells. One scFv GC4 inhibited self-renewal of GBM tumor sphere cells in vitro. We have further developed a full-length human IgG1 based on this scFv, and found that it potently inhibits proliferation of GBM tumor sphere cells and GBM cells grown in regular nonselective medium. Taken together, these results show that internalizing human scFvs targeting brain tumor sphere cells can be readily identified from a phage antibody display library, which could be useful for further development of novel therapies that target subpopulations of GBM cells to combat recurrence and resistance to treatment.
多形性胶质母细胞瘤（GBM）是最常见和侵袭性最强的原发性脑肿瘤，目前尚无治愈方法。对常规治疗的耐药性和肿瘤复发对这种疾病的治疗和管理构成了重大挑战，因此需要开发新的治疗策略。其他研究人员的先前研究表明，当在限制培养基中培养时，GBM 细胞的亚群可以作为神经球样细胞生长，并表现出增强的肿瘤起始能力和对治疗的耐药性。我们在这里报告了鉴定针对 GBM 肿瘤球体细胞的内化人单链抗体（scFv）。我们选择了一个大型的天然噬菌体抗体展示文库，该文库针对作为肿瘤球体生长的 GBM 细胞的糖基化依赖性 CD133 表位阳性亚群，鉴定了能够广泛靶向肿瘤球体细胞的内化 scFv，以及靶向 CD133 阳性亚群的 scFv。这些 scFv 被发现能够有效地被 GBM 肿瘤球体细胞内化。一种 scFv GC4 抑制了 GBM 肿瘤球体细胞的体外自我更新。我们进一步基于该 scFv 开发了全长人 IgG1，并发现它能够有效抑制 GBM 肿瘤球体细胞和在常规非选择性培养基中生长的 GBM 细胞的增殖。总之，这些结果表明，从噬菌体抗体展示文库中可以很容易地鉴定出针对脑肿瘤球体细胞的内化人 scFv，这可能有助于进一步开发针对 GBM 细胞亚群的新型治疗方法，以对抗复发和治疗耐药性。
