GIRLRG peptide

GIRLRG peptide is a synthetic hexapeptide (Gly-Ile-Arg-Leu-Arg-Gly) discovered via in vivo phage-display biopanning that specifically targets the 78 kDa glucose-regulated protein (GRP78), an endoplasmic reticulum stress chaperone overexpressed on the cell surface of various irradiated cancer cells and tumor-associated microvascular endothelial cells. GIRLRG binds to the ATPase domain of GRP78. It has been developed as a targeting ligand for cancer-specific drug delivery and noninvasive tumor imaging. When conjugated to polyethylene glycol (PEG) and radiolabeled with Indium-111 (111In-PEG-GIRLRG), it serves as a diagnostic imaging agent for single-photon emission computed tomography (SPECT) to detect tumors such as glioma, lung, pancreatic, esophageal, and cervical cancers. It has also been utilized to retarget adenoviruses for radiation-guided gene delivery and to target paclitaxel-encapsulated nanoparticles to tumors.

Other names

111In-PEG-GIRLRGGIRLRGGly-Ile-Arg-Leu-Arg-GlyPEG-GIRLRG