ERp29 regulates response to doxorubicin by a PERK-mediated mechanism

• Published in: Biochimica et biophysica acta Vol. 1813; no. 6; pp. 1165 - 1171
• Main Authors: Farmaki, E., Mkrtchian, S., Papazian, I., Papavassiliou, A.G., Kiaris, H.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.06.2011
• Subjects: Adriamycin; Animals; Antibiotics, Antineoplastic - pharmacology; Blotting, Western; Cell Line, Tumor; Cell Survival - drug effects; Cells, Cultured; Chemotherapy; Doxorubicin - pharmacology; Drug Resistance - genetics; eIF-2 Kinase - genetics; eIF-2 Kinase - metabolism; Embryo, Mammalian - cytology; ER stress; ERp29; Female; Fibroblasts - cytology; Fibroblasts - drug effects; Fibroblasts - metabolism; Heat-Shock Proteins - genetics; Heat-Shock Proteins - metabolism; Humans; Immunoprecipitation; Male; Medicin och hälsovetenskap; Mice; Mice, Knockout; PERK; Protein Binding; Reverse Transcriptase Polymerase Chain Reaction; RNA Interference; Tumor Suppressor Protein p53 - genetics; Tumor Suppressor Protein p53 - metabolism; UPR; ER stress; ERp29; Chemotherapy; PERK; Adriamycin; UPR
• ISSN: 0167-4889; 0006-3002; 1879-2596
• DOI: 10.1016/j.bbamcr.2011.03.003

ERp29 is an endoplasmic reticulum (ER) luminal protein with a putative secretion factor/escort chaperone function. Accumulated evidence has implicated ERp29 in the thyroglobulin secretion, polyoma virus transport and recently in carcinogenesis. ERp29 levels were elevated in the tumors of various origins and under the conditions of genotoxic stress, such as ionizing radiation. Here we report the induction of ERp29 during the treatment of cells with doxorubicin, a commonly used antineoplastic agent. Experiments in the p53 −/− cells and p53 knockout mouse revealed that doxorubicin effect on ERp29 is p53 dependent. The increase of ERp29 level appears to activate a negative feedback loop where the elevated amounts of ERp29 augment cell viability as shown by a clonogenic cell survival assay. To elucidate the mechanisms behind the doxorubicin effects we have studied the impact of ERp29 on the interaction with the ER stress-activated eukaryotic translation initiation factor 2-alpha kinase 3 (PERK) that was shown to facilitate tumor cells' resistance to drug toxicity. Co-immunoprecipitation demonstrated physical interaction of ERp29 with PERK and moreover, overexpression of ERp29 enhanced endogenous levels of PERK. Our results identify ERp29 as a novel regulator of PERK and provide evidence for the role of ER resident factors in the regulation of chemotherapeutic efficacy. These findings show that PERK may represent a nodal point between ER stress and chemotherapeutic response. ► Doxorubicin induces the levels of ERp29. ► ERp29 interacts physically with PERK. ► PERK levels are modulated by ERp29 expression. ► ERp29 modulates sensitivity to doxorubicin by a PERK-dependent manner.