About InVivoMAb anti-human/mouse GRP78 The N88 monoclonal antibody reacts with human and mouse Glucose Regulated Protein 78 (GRP78) also known as BiP or HSPA5. GRP78 is a stress inducible, pro-survival, endoplasmic reticulum chaperone in the HSP70 family. Cell Surface GRP78 acts as a multifunctional receptor that affects both cell proliferation and viability. GRP78 is involved in many cellular processes, including translocating newly synthesized polypeptides across the ER membrane, facilitating the folding and assembly of proteins, targeting misfolded proteins for ER-associated degradation (ERAD), regulating calcium homeostasis, and serving as an ER stress sensor. Expression of cell surface GRP78 is associated with increased malignancy and resistance to chemotherapy and radiotherapy in various cancers, particularly prostate cancer. The N88 antibody binds to the N‐terminal domain of GRP78 and has been shown to accelerate tumor growth in a B16F1 melanoma tumor model. InVivoMAb anti-human/mouse GRP78 Specifications IsotypeMouse IgG1, κ Recommended Isotype Control(s)InVivoMAb mouse IgG1 isotype control, unknown specificity Recommended Dilution BufferInVivoPure pH 7.0 Dilution Buffer ImmunogenFull-length recombinant GRP78 protein Reported Applicationsin vivo administration Functional assays FormulationPBS, pH 7.0 Contains no stabilizers or preservatives Endotoxin<2EU/mg (<0.002EU/μg) Determined by LAL gel clotting assay Purity>95% Determined by SDS-PAGE Sterility0.2 μm filtered ProductionPurified from cell culture supernatant in an animal-free facility PurificationProtein G Molecular Weight150 kDa StorageThe antibody solution should be stored at the stock concentration at 4°C. Do not freeze. Application ReferencesInVivoMAb anti-human/mouse GRP78 (CLONE: N88)de Ridder GG, Ray R, Pizzo SV (2012). "A murine monoclonal antibody directed against the carboxyl-terminal domain of GRP78 suppresses melanoma growth in mice" Melanoma Res 22(3):225-35. PubMedThe HSP70 family member GRP78 is a selective tumor marker upregulated on the surface of many tumor cell types, including melanoma, where it acts as a growth factor receptor-like protein. Receptor-recognized forms of the proteinase inhibitor α2-macroglobulin (α2M*) are the best-characterized ligands for GRP78, but in melanoma and other cancer patients, autoantibodies arise against the NH2-terminal domain of GRP78 that react with tumor cell-surface GRP78. This causes the activation of signaling cascades that are proproliferative and antiapoptotic. Antibodies directed against the COOH-terminal domain of GRP78, however, upregulate p53-mediated proapoptotic signaling, leading to cell death. Here, we describe the binding characteristics, cell signaling properties, and downstream cellular effects of three novel murine monoclonal antibodies. The NH2-terminal domain-reactive antibody, N88, mimics α2M* as a ligand and drives PI 3-kinase-dependent activation of Akt and the subsequent stimulation of cellular proliferation in vitro. The COOH-terminal domain-reactive antibody, C38, acts as an antagonist of both α2M* and N88, whereas another, C107, directly induces apoptosis in vitro. In a murine B16F1 melanoma flank tumor model, we demonstrate the acceleration of tumor growth by treatment with N88, whereas C107 significantly slowed tumor growth whether administered before (P<0.005) or after (P<0.05) tumor implantation.
