Functional characterization of an scFv-Fc antibody that immunotherapeutically targets the common cancer cell surface...

Area of Science:

• Oncology
• Immunology
• Biotechnology

Background:

• Chondroitin sulfate proteoglycan 4 (CSPG4) is highly expressed on cancer cells, including cancer-initiating cells, and is a promising target for antibody-based cancer immunotherapy.
• The clinical application of CSPG4-targeting antibodies has been limited by the absence of specific humanized or fully human monoclonal antibodies.

Purpose of the Study:

• To develop and characterize a fully human single-chain antibody fragment (scFv) with specificity for CSPG4.
• To evaluate the therapeutic potential of the engineered antibody, scFv-FcC21, in preclinical cancer models.

Main Methods:

• A human scFv phage display library was screened using CSPG4-expressing melanoma cells, with engineered CDR3 regions to optimize binding.
• The selected scFv was recombinantly fused to a human IgG1 Fc region to create the fully human antibody scFv-FcC21.
• Specificity, in vitro anti-tumor activity (growth, migration), and in vivo efficacy against human tumor xenografts were assessed.

Main Results:

• scFv-FcC21 demonstrated specificity for CSPG4 and recognized a broad range of tumors, including neuroectodermal tumors, carcinomas, mesotheliomas, sarcomas, and myeloid leukemias.
• The antibody inhibited tumor cell growth and migration in vitro.
• scFv-FcC21 suppressed the growth of human tumor xenografts in vivo, mediated by the inhibition of ERK and FAK signaling pathways.

Conclusions:

• The fully human CSPG4-specific antibody scFv-FcC21 is a potential therapeutic candidate for various cancers expressing CSPG4.
• scFv-FcC21 exhibits significant antitumor activity through the inhibition of key tumor cell signaling pathways.