InVivoMAb anti-human/mouse GRP78
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$159.00 - $4,155.00
Product DetailsThe C38 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 C38 antibody binds to the C‐terminal domain of GRP78 and has been shown to have anti-tumoral potential in various in vitro and in vivo tumor models.
|Isotype||Mouse IgG2b, κ|
|Recommended Isotype Control(s)||InVivoMAb mouse IgG2b isotype control, unknown specificity|
|Recommended Dilution Buffer||InVivoPure pH 7.0 Dilution Buffer|
|Immunogen||Full-length recombinant murine GRP78 protein|
in vivo GRP78 blockade
in vitro GRP78 blockade
PBS, pH 7.0
Contains no stabilizers or preservatives
Determined by LAL gel clotting assay
Determined by SDS-PAGE
|Sterility||0.2 µm filtration|
|Production||Purified from tissue culture supernatant in an animal free facility|
|Molecular Weight||150 kDa|
|Storage||The antibody solution should be stored at the stock concentration at 4°C. Do not freeze.|
Recommended Isotype Control(s)
Recommended Dilution Buffer
in vitro GRP78 blockade
Trink J, Ahmed U, O', Neil K, Li R, Gao B, Krepinsky JC. (2023). "Cell surface GRP78 regulates TGFβ1-mediated profibrotic responses via TSP1 in diabetic kidney disease" Front Pharmacol 14:1098321. PubMed
Diabetic kidney disease (DKD) is the leading cause of kidney failure in North America, characterized by glomerular accumulation of extracellular matrix (ECM) proteins. High glucose (HG) induction of glomerular mesangial cell (MC) profibrotic responses plays a central role in its pathogenesis. We previously showed that the endoplasmic reticulum resident GRP78 translocates to the cell surface in response to HG, where it mediates Akt activation and downstream profibrotic responses in MC. Transforming growth factor β1 (TGFβ1) is recognized as a central mediator of HG-induced profibrotic responses, but whether its activation is regulated by cell surface GRP78 (csGRP78) is unknown. TGFβ1 is stored in the ECM in a latent form, requiring release for biological activity. The matrix glycoprotein thrombospondin 1 (TSP1), known to be increased in DKD and by HG in MC, is an important factor in TGFβ1 activation. Here we determined whether csGRP78 regulates TSP1 expression and thereby TGFβ1 activation by HG. Methods: Primary mouse MC were used. TSP1 and TGFβ1 were assessed using standard molecular biology techniques. Inhibitors of csGRP78 were: 1) vaspin, 2) the C-terminal targeting antibody C38, 3) siRNA downregulation of its transport co-chaperone MTJ-1 to prevent GRP78 translocation to the cell surface, and 4) prevention of csGRP78 activation by its ligand, active α2-macroglobulin (α2M*), with the neutralizing antibody Fα2M or an inhibitory peptide. Results: TSP1 transcript and promoter activity were increased by HG, as were cellular and ECM TSP1, and these required PI3K/Akt activity. Inhibition of csGRP78 prevented HG-induced TSP1 upregulation and deposition into the ECM. The HG-induced increase in active TGFβ1 in the medium was also inhibited, which was associated with reduced intracellular Smad3 activation and signaling. Overexpression of csGRP78 increased TSP-1, and this was further augmented in HG. Discussion: These data support an important role for csGRP78 in regulating HG-induced TSP1 transcriptional induction via PI3K/Akt signaling. Functionally, this enables TGFβ1 activation in response to HG, with consequent increase in ECM proteins. Means of inhibiting csGRP78 signaling represent a novel approach to preventing fibrosis in DKD.
in vitro GRP78 blockade, Western Blot, Flow Cytometry
Gopal U, Mowery Y, Young K, Pizzo SV. (2019). "Targeting cell surface GRP78 enhances pancreatic cancer radiosensitivity through YAP/TAZ protein signaling" J Biol Chem 294(38):13939-13952. PubMed
Ionizing radiation (IR) can promote migration and invasion of cancer cells, but the basis for this phenomenon has not been fully elucidated. IR increases expression of glucose-regulated protein 78kDa (GRP78) on the surface of cancer cells (CS-GRP78), and this up-regulation is associated with more aggressive behavior, radioresistance, and recurrence of cancer. Here, using various biochemical and immunological methods, including flow cytometry, cell proliferation and migration assays, Rho activation and quantitative RT-PCR assays, we investigated the mechanism by which CS-GRP78 contributes to radioresistance in pancreatic ductal adenocarcinoma (PDAC) cells. We found that activated α2-Macroglobulin (α2M*) a ligand of the CS-GRP78 receptor, induces formation of the AKT kinase (AKT)/DLC1 Rho-GTPase-activating protein (DLC1) complex and thereby increases Rho activation. Further, CS-GRP78 activated the transcriptional coactivators Yes-associated protein (YAP) and tafazzin (TAZ) in a Rho-dependent manner, promoting motility and invasiveness of PDAC cells. We observed that radiation-induced CS-GRP78 stimulates the nuclear accumulation of YAP/TAZ and increases YAP/TAZ target gene expressions. Remarkably, targeting CS-GRP78 with C38 monoclonal antibody (Mab) enhanced radiosensitivity and increased the efficacy of radiation therapy by curtailing PDAC cell motility and invasion. These findings reveal that CS-GRP78 acts upstream of YAP/TAZ signaling and promote migration and radiation-resistance in PDAC cells. We therefore conclude that, C38 Mab is a promising candidate for use in combination with radiation therapy to manage PDAC.
in vitro GRP78 blockade
Gopal U, Pizzo SV. (2017). "Cell surface GRP78 promotes tumor cell histone acetylation through metabolic reprogramming: a mechanism which modulates the Warburg effect" Oncotarget 8(64):107947-107963. PubMed
Acetyl coenzyme A (acetyl-CoA) is essential for histone acetylation, to promote cell proliferation by regulating gene expression. However, the underlying mechanism(s) governing acetylation remains poorly understood. Activated α2-Macroglobulin (α2M*) signals through tumor Cell Surface GRP78 (CS-GRP78) to regulate tumor cell proliferation through multiple signaling pathway. Here, we demonstrate that the α2M*/CS-GRP78 axis regulates acetyl-CoA synthesis and thus functions as an epigenetic modulator by enhancing histone acetylation in cancer cells. α2M*/CS-GRP78 signaling induces and activates glucose-dependent ATP-citrate lyase (ACLY) and promotes acetate-dependent Acetyl-CoA Synthetase (ACSS1) expression by regulating AKT pathways to acetylate histones and other proteins. Further, we show that acetate itself regulates ACLY and ACSS1 expression through a feedback loop in an AKT-dependent manner. These studies demonstrate that α2M*/CS-GRP78 signaling is a central mechanism for integrating glucose and acetate-dependent signaling to induce histone acetylation. More importantly, targeting the α2M*/CS-GRP78 axis with C38 Monoclonal antibody (Mab) abrogates acetate-induced acetylation of histones and proteins essential for proliferation and survival under hypoxic stress. Furthermore, C38 Mab significantly reduced glucose uptake and lactate consumption which definitively suggests the role of aerobic glycolysis. Collectively, besides its ability to induce fatty acid synthesis, our study reveals a new mechanism of epigenetic regulation by the α2M*/CS-GRP78 axis to increase histone acetylation and promote cell survival under unfavorable condition. Therefore CS-GRP78 might be effectively employed to target the metabolic vulnerability of a wide spectrum of tumors and C38 Mab represents such a potential therapeutic agent.
in vivo GRP78 blockade
Mo L, Bachelder RE, Kennedy M, Chen PH, Chi JT, Berchuck A, Cianciolo G, Pizzo SV. (2015). "Syngeneic Murine Ovarian Cancer Model Reveals That Ascites Enriches for Ovarian Cancer Stem-Like Cells Expressing Membrane GRP78" Mol Cancer Ther 14(3):747-56. PubMed
Patients with ovarian cancer are generally diagnosed at FIGO (International Federation of Gynecology and Obstetrics) stage III/IV, when ascites is common. The volume of ascites correlates positively with the extent of metastasis and negatively with prognosis. Membrane GRP78, a stress-inducible endoplasmic reticulum chaperone that is also expressed on the plasma membrane ((mem)GRP78) of aggressive cancer cells, plays a crucial role in the embryonic stem cell maintenance. We studied the effects of ascites on ovarian cancer stem-like cells using a syngeneic mouse model. Our study demonstrates that ascites-derived tumor cells from mice injected intraperitoneally with murine ovarian cancer cells (ID8) express increased (mem)GRP78 levels compared with ID8 cells from normal culture. We hypothesized that these ascites-associated (mem)GRP78(+) cells are cancer stem-like cells (CSC). Supporting this hypothesis, we show that (mem)GRP78(+) cells isolated from murine ascites exhibit increased sphere forming and tumor initiating abilities compared with (mem)GRP78(-) cells. When the tumor microenvironment is recapitulated by adding ascites fluid to cell culture, ID8 cells express more (mem)GRP78 and increased self-renewing ability compared with those cultured in medium alone. Moreover, compared with their counterparts cultured in normal medium, ID8 cells cultured in ascites, or isolated from ascites, show increased stem cell marker expression. Antibodies directed against the carboxy-terminal domain of GRP78: (i) reduce self-renewing ability of murine and human ovarian cancer cells preincubated with ascites and (ii) suppress a GSK3α-AKT/SNAI1 signaling axis in these cells. Based on these data, we suggest that (mem)GRP78 is a logical therapeutic target for late-stage ovarian cancer.
in vitro GRP78 blockade, Flow Cytometry
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. PubMed
The 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.