Solute carrier family 28 member 1 (hCNT1) (hCNT1)

Human concentrative nucleoside transporter 1 (hCNT1), encoded by the SLC28A1 gene, is a high-affinity, sodium-dependent symporter specialized in the concentrative uptake of pyrimidine nucleosides such as cytidine, thymidine, and uridine. It is primarily localized to the apical membranes of polarized epithelial cells in the kidney, liver, and small intestine, where it facilitates the salvage of nucleosides and the disposition of various drugs. In clinical oncology, hCNT1 is a critical determinant of drug efficacy because it is a primary route for the intracellular entry of several nucleoside-derived chemotherapeutic agents, including gemcitabine and cytarabine. Many malignant tumors, particularly pancreatic, breast, and gynecological cancers, frequently exhibit downregulation or total loss of hCNT1, which directly correlates with increased chemoresistance and a poorer prognosis. Beyond its role as a transporter, hCNT1 is thought to possess "transceptor" properties, potentially acting as a tumor suppressor by influencing cell cycle progression and inducing non-apoptotic cell death independently of its translocation activity.

Other names

SLC28A1CNT1Sodium/nucleoside cotransporter 1Na(+)/nucleoside cotransporter 1Sodium-coupled nucleoside transporter 1

Sodium-dependent symporter (1:1 stoichiometry) mediating the concentrative, inward transport of pyrimidine nucleosides and their analogs across the plasma membrane.