Dataset Information

GRP78-targeting subtilase cytotoxin sensitizes cancer cells to photodynamic therapy.

ABSTRACT: Glucose-regulated protein 78 (GRP78) is an endoplasmic reticulum (ER)-resident chaperone and a major regulator of the unfolded protein response (UPR). Accumulating evidence indicate that GRP78 is overexpressed in many cancer cell lines, and contributes to the invasion and metastasis in many human tumors. Besides, GRP78 upregulation is detected in response to different ER stress-inducing anticancer therapies, including photodynamic therapy (PDT). This study demonstrates that GRP78 mRNA and protein levels are elevated in response to PDT in various cancer cell lines. Stable overexpression of GRP78 confers resistance to PDT substantiating its cytoprotective role. Moreover, GRP78-targeting subtilase cytotoxin catalytic subunit fused with epidermal growth factor (EGF-SubA) sensitizes various cancer cells to Photofrin-mediated PDT. The combination treatment is cytotoxic to apoptosis-competent SW-900 lung cancer cells, as well as to Bax-deficient and apoptosis-resistant DU-145 prostate cancer cells. In these cells, PDT and EGF-SubA cytotoxin induce protein kinase R-like ER kinase and inositol-requiring enzyme 1 branches of UPR and also increase the level of C/EBP (CCAAT/enhancer-binding protein) homologous protein, an ER stress-associated apoptosis-promoting transcription factor. Although some apoptotic events such as disruption of mitochondrial membrane and caspase activation are detected after PDT, there is no phosphatidylserine plasma membrane externalization or DNA fragmentation, suggesting that in DU-145 cells the late apoptotic events are missing. Moreover, in SW-900 cells, EGF-SubA cytotoxin potentiates PDT-mediated cell death but attenuates PDT-induced apoptosis. In addition, the cell death cannot be reversed by caspase inhibitor z-VAD, confirming that apoptosis is not a major cell death mode triggered by the combination therapy. Moreover, no typical features of necrotic or autophagic cell death are recognized. Instead, an extensive cellular vacuolation of ER origin is observed. Altogether, these findings indicate that PDT and GRP78-targeting cytotoxin treatment can efficiently kill cancer cells independent on their apoptotic competence and triggers an atypical, non-apoptotic cell death.

SUBMITTER: Firczuk M

PROVIDER: S-EPMC3730435 | biostudies-literature | 2013 Jul

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

GRP78-targeting subtilase cytotoxin sensitizes cancer cells to photodynamic therapy.

Firczuk M M Gabrysiak M M Barankiewicz J J Domagala A A Nowis D D Kujawa M M Jankowska-Steifer E E Wachowska M M Glodkowska-Mrowka E E Korsak B B Winiarska M M Golab J J

Cell death & disease 20130725

Glucose-regulated protein 78 (GRP78) is an endoplasmic reticulum (ER)-resident chaperone and a major regulator of the unfolded protein response (UPR). Accumulating evidence indicate that GRP78 is overexpressed in many cancer cell lines, and contributes to the invasion and metastasis in many human tumors. Besides, GRP78 upregulation is detected in response to different ER stress-inducing anticancer therapies, including photodynamic therapy (PDT). This study demonstrates that GRP78 mRNA and protei ...[more]

PMID: 23887632

Similar Datasets

Project description:PurposeLocal tumor progression is a cause of significant morbidity and mortality in patients with pancreatic ductal adenocarcinoma (PDAC) with surgically unresectable disease. Novel and effective approaches to accomplish durable local control are urgently needed. We tested whether CPI-613 (devimistat), a first-in-class investigational small molecule inhibitor of mitochondrial metabolism, was capable of altering cancer cell energy metabolism and sensitizing PDAC cells to radiation therapy (RT).Methods and materialsThe effect of a combined treatment of RT with CPI-613 on the viability of, clonogenic potential of, and cell death induction in PDAC cells (MiaPaCa-2 and Panc-1) was determined using a trypan blue dye exclusion assay, a colony formation assay, and a 7-amino-actinomycin D assay, respectively. The synergistic effects of CPI-613-RT and chemotherapeutic agents (gemcitabine or 5-fluorouracil) were measured in MiaPaCa-2 cells using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and spheroid formation assay. Changes in energy metabolism were determined by profiling metabolites treated with either RT, CPI-613, or both using liquid chromatography-mass spectrometry.ResultsThis study demonstrates that a combination of single-fraction RT (2 and 10 Gy) with CPI-613 significantly inhibits PDAC cell growth compared with RT alone. Molecular analysis revealed inhibition of α-ketoglutarate dehydrogenase at the protein level. In addition, we demonstrate enhanced cell death of PDAC cells when treated with RT-CPI-613 combination. Targeted metabolomic analysis on PDAC cells post-CPI-613-RT treatment revealed alterations in key mitochondrial metabolites, with broader target engagement by the combination treatment, indicating the sensitization of CPI-613-treated PDAC cells to RT. Furthermore, a combination treatment of CPI-613 with either gemcitabine or 5-fluorouracil in the presence of 2 Gy RT synergistically inhibits PDAC cell proliferation.ConclusionsOur results support a novel combination of CPI-613-RT that warrants further preclinical and early-phase clinical investigations. A phase 1 trial designed to identify the maximum tolerated dose of CPI-613 in combination with chemo-RT in patients with PDAC was recently initiated (NCT05325281).

Dataset Information

GRP78-targeting subtilase cytotoxin sensitizes cancer cells to photodynamic therapy.

Publications

GRP78-targeting subtilase cytotoxin sensitizes cancer cells to photodynamic therapy.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets