Glypican‐1‐Targeted Antibody–Drug Conjugate Exhibits Antitumor Effects Against Oral Squamous Cell Carcinoma

BACKGROUND: Oral squamous cell carcinoma (OSCC) is a major health concern with limited therapeutic options. Glypican-1 (GPC1), a heparan sulphate proteoglycan, has been implicated in several malignancies; however, its therapeutic role in OSCC remains elusive. This study investigated the potential of a novel glypican-1 antibody-drug conjugate (GPC1-ADC) conjugated with monomethyl auristatin E as a therapeutic strategy for OSCC. METHODS: GPC1 expression in OSCC tissues was examined by immunohistochemistry using tissue microarrays and by western blotting in OSCC cell lines. The cytotoxicity of GPC1-ADC was assessed using in vitro viability assays, and its effects on the cell cycle and apoptosis were analyzed using flow cytometry and caspase-3/7 activity assays. In vivo antitumor efficacy was evaluated using OSCC cell line-derived and patient-derived xenograft (PDX) mouse models. RESULTS: = 0.053-0.117 nM), induced G2/M-phase arrest, and activated caspase-3/7, indicating apoptosis. In vivo, high-dose GPC1-ADC markedly inhibited tumor growth in both xenograft and PDX models compared with control treatments, without causing weight loss. CONCLUSION: GPC1-ADC demonstrated potent and specific antitumor activity against GPC1-expressing OSCC in vitro and in vivo. These findings suggest that GPC1-ADC is a promising therapeutic candidate for OSCC and may provide a basis for new treatment strategies; however, further preclinical and clinical evaluation is warranted.