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A GPC3-targeting Bispecific Antibody, GPC3-S-Fab, with Potent Cytotoxicity

This protocol describes the construction and functional studies of a bispecific antibody (bsAb), GPC3-S-Fab. bsAbs can recognize two different epitopes ...

Sun Yat-sen University

Chitosan and capsaicin are compounds extracted from natural products and have been indicated to lower body weight and prevent fatty liver. However, their applications are limited by poor oral bioavailability, low compliance and some serious side effects. To solve these problems, we successfully prepared chitosan microspheres (CTMS) and chitosan-capsaicin microspheres (CCMS) in previous study. Therefore, in the present study, we evaluated the ability of CTMS and CCMS to eliminate lipid accumulation in hepatocytesand also characterized their pharmacokinetic parameters after administration. The results showed that the two microspheres could significantly reduce intracellular lipid accumulation and dose-dependently improve the triglyceride (TG) content in HepG2 cells. A pharmacokinetic study indicated that CTMS and CCMS were distributed in almost all of the measured tissues, especially liver and kidney, and that their absorption was better than those of chitosan and capsaicin. Simultaneously, the prolonged circulating half-lives, the lower clearance and higher plasma concentration of CTMS and CCMS showed that their bioavailability was effectively enhanced. All of the results indicated that the lipid accumulation inhibition of CTMS and CCMS was better than that of chitosan and capsaicin, and that these microspheres can be developed as preventive agents for fatty liver or obesity.

 inhibition of lipid accumulation induced by oleic acid and  pharmacokinetics of chitosan microspheres (CTMS) and chitosan-capsaicin microspheres (CCMS).

Among different cancer immunotherapy approaches, bispecific antibodies (BsAbs) are of great interest due to their ability to recruit immune cells to kill tumor cells directly. Various BsAbs against Her2 tumor cells have been proposed with potent cytotoxic activities. However, most of these formats require extensive processing to obtain heterodimeric bispecific antibodies. In this study, we describe a bispecific antibody, BiHC (bispecific Her2-CD3 antibody), constructed with a single-domain anti-Her2 and a single-chain Fv (variable fragment) of anti-CD3 in an IgG-like format. In contrast to most IgG-like BsAbs, the two arms in BiHC have different molecular weights, making it easier to separate hetero- or homodimers. BiHC can be expressed in Escherichia coli and purified via Protein A affinity chromatography. The purified BiHC can recruit T cells and induce specific cytotoxicity of Her2-expressing tumor cells in vitro. The BiHC can also efficiently inhibit the tumor growth in vivo. Thus, BiHC is a promising candidate for the treatment of Her2-positive cancers.

BiHC, a T-Cell-Engaging Bispecific Recombinant Antibody, Has Potent Cytotoxic Activity Against Her2 Tumor Cells.

Human epidermal growth factor receptor 2 (HER2) is frequently overexpressed and activated in metastatic breast cancers. Monoclonal antibodies targeting Her2, such as trastuzumab and pertuzumab, have become important targeted therapies for patients with HER2-positive breast cancer. Both trastuzumab and pertuzumab can reduce Her2 positive tumor burden by inhibiting Her2 signaling and inducing ADCC activities (antibody dependent cell-mediated cytotoxicity). In this study, we have generated a bispecific antibody, Her2(Per)-S-Fab, by linking the pertuzumab Fab to an anti-CD16 single domain antibody. The Her2(Per)-S-Fab can be expressed and purified efficiently from Escherichia coli. In vitro and in vivo experiments showed Her2(Per)-S-Fab had potent cytotoxicity against Her2-positive tumor cells. Thus, Her2(Per)-S-Fab may provide an alternative to treat Her2-positive cancer patients.

A Bispecific Antibody Based on Pertuzumab Fab Has Potent Antitumor Activity.

Obesity is a global disease that causes many metabolic disorders. However, effective agents for the prevention or treatment of obesity remain limited. This study investigated the anti-obesity effect and mechanism of chitosan oligosaccharide capsules (COSCs) on rats suffering from obesity induced by a high-fat diet (HFD). After the eight-week administration of COSCs on obese rats, the body weight gain, fat/body ratio, and related biochemical indices were measured. The hepatic expressions of the leptin signal pathway (JAK2-STAT3) and gene expressions of adipogenesis-related targets were also determined. Our data showed that COSCs can regulate body weight gain, lipids, serum alanine aminotransferase, and aspartate aminotransferase, as well as upregulate the hepatic leptin receptor-b (LepRb) and the phosphorylation of JAK2 and STAT3. Meanwhile, marked increased expressions of liver sterol regulatory element-binding protein-1c, fatty acid synthase, acetyl-CoA carboxylase, 3-hydroxy-3-methylglutaryl-CoA reductase, adiponectin, adipose peroxisome proliferator-activated receptor γ, CCAAT-enhancer binding protein α, adipose differentiation-related protein, and SREBP-1c were observed. The results suggested that COSCs activate the JAK2-STAT3 signaling pathway to alleviate leptin resistance and suppress adipogenesis to reduce lipid accumulation. Thus, they can potentially be used for obesity treatment.

Anti-Obesity Effect of Chitosan Oligosaccharide Capsules (COSCs) in Obese Rats by Ameliorating Leptin Resistance and Adipogenesis.

Bispecific antibodies that engage immune cells to kill cancer cells are actively pursued in cancer immunotherapy. Different types of bispecific antibodies, including single-chain fragments, Fab fragments, nanobodies, and immunoglobulin Gs (IgGs), have been studied. However, the low molecular weight of bispecific antibodies with single-chain or Fab fragments generally leads to their rapid clearance in vivo, which limits the therapeutic potential of these bispecific antibodies.

Haitao Pan

School of Pharmaceutical Sciences,
Center for Cellular & Structural Biology

Sun Yat-sen University

A GPC3-targeting Bispecific Antibody, GPC3-S-Fab, with Potent Cytotoxicity

Haitao Pan

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Sun Yat-sen University

A GPC3-targeting Bispecific Antibody, GPC3-S-Fab, with Potent Cytotoxicity

School of Pharmaceutical Sciences,
Center for Cellular & Structural Biology