Non-functional P2X purinoceptor 7 (nfP2X7) (nfP2X7)

The non-functional P2X7 receptor (nfP2X7) is a distinct conformational variant of the P2X purinoceptor 7, an ATP-gated cation channel. While the wild-type P2X7 receptor can form a large transmembrane pore that triggers apoptosis, the nfP2X7 variant found on cancer cells is unable to form this pore, allowing the cells to survive and proliferate in the high-ATP environment of the tumor microenvironment (Gilbert et al., 2019, Scientific Reports). This functional defect is associated with a structural change that exposes the E200 epitope, a sequence of amino acids (residues 200–216) that is hidden in the functional receptor (Barden et al., 2003, Journal of Biological Chemistry). The nfP2X7 receptor is expressed across a wide range of malignancies, including basal cell carcinoma, prostate cancer, and breast cancer, but is absent or in a closed conformation on healthy cells (Biosceptre, 2024). This makes the E200 epitope an ideal target for highly specific cancer therapies, such as the monoclonal antibody BIL010t, which binds to the epitope to induce cell death (NCI Drug Dictionary). By targeting a cancer-specific conformation rather than the protein itself, these therapies aim to achieve high efficacy with minimal off-target toxicity.

Other names

nfP2X7Non-functional P2X7 receptorP2X7 receptor E200 epitopeP2RX7 (non-functional)Non-pore functional P2X7 receptor

Antibodies or CAR-T cells specifically bind to the exposed E200 epitope on the non-functional P2X7 receptor, which is uniquely present on cancer cells. This binding inhibits the receptor's anti-apoptotic activity and induces cell death through apoptosis or immune-mediated mechanisms like antibody-dependent cellular cytotoxicity (ADCC), while sparing healthy cells that express the functional, closed-conformation receptor.