Glypican-2 (GPC2) (GPC2)

Glypican-2 (GPC2), also known as cerebroglycan, is a cell surface heparan sulfate proteoglycan (HSPG) anchored to the plasma membrane via a glycosylphosphatidylinositol (GPI) anchor. It is primarily expressed during the development of the central nervous system, where it regulates neuronal cell adhesion, neurite outgrowth, and axon guidance. While its expression is highly restricted in normal adult tissues, GPC2 is significantly overexpressed in several aggressive pediatric and adult malignancies, including high-risk neuroblastoma, retinoblastoma, and small-cell lung cancer. In these cancers, GPC2 acts as an oncoprotein by facilitating the activation of key signaling pathways such as Wnt/beta-catenin and PI3K/AKT, often driven by MYCN amplification. Due to its tumor-specific expression profile, the GPC2 extracellular domain is an attractive target for immunotherapies, including chimeric antigen receptor (CAR) T cells, antibody-drug conjugates (ADCs), and immunotoxins. Clinical trials are currently investigating GPC2-targeted CAR T cells for the treatment of relapsed or refractory neuroblastoma. Potential safety concerns associated with GPC2-targeted therapies include cytokine release syndrome and neurotoxicity, as well as the risk of on-target off-tumor effects if low-level expression is present in normal tissues.

Other names

CerebroglycanGPC2

GPC2-targeted therapies utilize the protein's extracellular domain to induce tumor cell death through multiple pathways. Chimeric antigen receptor (CAR) T cells provide direct T-cell mediated cytotoxicity upon binding to GPC2 on the tumor cell surface. Antibody-drug conjugates (ADCs) like D3-GPC2-PBD are internalized after binding, delivering cytotoxic payloads that cause DNA damage and apoptosis. Additionally, GPC2-specific antibodies and immunotoxins can inhibit oncogenic signaling by disrupting the interaction between GPC2 and ligands such as Wnt3a or Midkine, thereby suppressing the Wnt/beta-catenin and PI3K/AKT pathways.