Department of Experimental and Clinical Medicine, Section of Internal Medicine, University of Florence, Firenze, Italy.
Department of Biomedical and Clinical Sciences, Section of General Pathology, University of Florence, Firenze, Italy.
Mol Cancer Ther. 2021 Aug;20(8):1338-1349. doi: 10.1158/1535-7163.MCT-20-1111. Epub 2021 May 27.
mAbs, either mono- or bispecific (bsAb), represent one of the most successful approaches to treat many types of malignancies. However, there are certain limitations to the use of full length mAbs for clinical applications, which can be overcome by engineered antibody fragments. The aim of this study was to develop a small bsAb, in the format of a single-chain diabody (scDb), to efficiently target two proteins, the hERG1 potassium channel and the β1 subunit of integrin receptors, which specifically form a macromolecular complex in cancer cells. We provide evidence that the scDb we produced binds to the hERG1/β1 complex in cancer cells and tissues, but does not bind to the hERG1 channel in nonpathologic tissues, in particular the heart. The scDb-hERG1-β1 (i) downregulates the formation of the hERG1/β1 complex, (ii) inhibits Akt phosphorylation and HIF-1α expression, and (iii) decreases cell survival, proliferation, and migration These effects only occur in cancer cells (either colon, pancreatic, or breast), but not in normal cells. , the scDb-hERG1-β1 shows a good pharmacokinetic profile, with a half-life of 13.5 hours and no general, cardiac, or renal toxicity when injected intravenously up to the dose of 8 mg/kg. The scDb-hERG1-β1 accumulates into subcutaneous xenografted tumors, arising from either colon or pancreatic human cancer cells, and induces a reduction of tumor growth and vascularization. Overall, the scDb-hERG1-β1 represents an innovative single-chain bispecific antibody for therapeutic applications in solid cancers that overexpress the hERG1/β1 integrin signaling complex.
单克隆抗体（mAbs），无论是单特异性（monoAb）还是双特异性（bsAb），都是治疗多种恶性肿瘤最成功的方法之一。然而，全长 mAbs 在临床应用中存在一定的局限性，可以通过工程化抗体片段来克服。本研究旨在开发一种小的 bsAb，即单链二价体（scDb），以有效靶向两种蛋白，即 hERG1 钾通道和整合素受体的 β1 亚基，这两种蛋白在癌细胞中特异性形成大分子复合物。我们提供的证据表明，我们产生的 scDb 与癌细胞和组织中的 hERG1/β1 复合物结合，但不与非病理组织中的 hERG1 通道结合，特别是心脏。scDb-hERG1-β1（i）下调 hERG1/β1 复合物的形成，（ii）抑制 Akt 磷酸化和 HIF-1α 表达，（iii）降低细胞存活、增殖和迁移。这些作用仅发生在癌细胞（结肠、胰腺或乳腺癌）中，而不在正常细胞中。此外，scDb-hERG1-β1 表现出良好的药代动力学特征，半衰期为 13.5 小时，静脉注射高达 8mg/kg 的剂量时无全身、心脏或肾脏毒性。scDb-hERG1-β1 积累到源自结肠或胰腺人癌细胞的皮下异种移植肿瘤中，并诱导肿瘤生长和血管生成减少。总体而言，scDb-hERG1-β1 代表了一种用于治疗过度表达 hERG1/β1 整合素信号复合物的实体癌的创新单链双特异性抗体。
