Contribution of epigenetic silencing of tumor necrosis factor-related apoptosis inducing ligand receptor 1 (DR4) to TRAIL resistance and ovarian cancer.
Dysregulation of apoptosis may support tumorigenesis by allowing cells to live beyond their normally intended life span. The various receptors for tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) are located on chromosome 8p21.2, a region frequently deleted in ovarian cancer. Lack of expression of TRAIL receptor 1 (death receptor 4, DR4) correlates with resistance to TRAIL-induced apoptosis in ovarian cancer cells. Reconstitution of DR4 in the TRAIL-resistant A2780 ovarian cancer cell line was investigated with the demethylating agent 5-aza-2'-deoxycytidine and transient gene transfer. Regulation of other genes in the TRAIL pathway by 5-aza-2'-deoxycytidine was assessed in DNA GeneChip experiments. Primary ovarian cancers were analyzed by methylation-specific PCR and immunohistochemical analysis of a tissue microarray. Regulation of DR4 expression by demethylation or transient transfection is of functional relevance for TRAIL resistance in an ovarian cancer cell line. Hypermethylation of the DR4 promoter could be found in 10 of 36 (27.7%) DNAs isolated from ovarian cancer tissue. In an independent set of 68 ovarian cancer cases, a complete loss or down-regulation of DR4 protein expression was observed 10.3% and 8.8% patients, respectively. A significant (P = 0.019) majority of these patients was below 50 years of age. Our findings show a functional relevance of the level of DR4 expression in ovarian cancer and suggest a substantial contribution of DR4 hypermethylation and consequent loss of DR4 expression to ovarian cancer pathogenesis, particularly in premenopausal patients.
Horak
Peter
P
Clinical Division of Oncology, Department of Medicine I, University Hospital, Währinger Gürtel 18-20, A-1090 Vienna, Austria.
Pils
Dietmar
D
Haller
Griet
G
Pribill
Ingrid
I
Roessler
Max
M
Tomek
Sandra
S
Horvat
Reinhard
R
Zeillinger
Robert
R
Zielinski
Christoph
C
Krainer
Michael
M
D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D051017:Apoptosis Regulatory Proteins; D001374:Azacitidine / Q000031:analogs & derivatives / Q000494:pharmacology; D045744:Cell Line, Tumor; D000077209:Decitabine; D019008:Drug Resistance, Neoplasm; D044127:Epigenesis, Genetic; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D020868:Gene Silencing; D006801:Humans; D007150:Immunohistochemistry; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D010051:Ovarian Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D018124:Receptors, Tumor Necrosis Factor / Q000378:metabolism*; D053221:TNF-Related Apoptosis-Inducing Ligand; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism*
D000964:Antimetabolites, Antineoplastic; D051017:Apoptosis Regulatory Proteins; D008562:Membrane Glycoproteins; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D018124:Receptors, Tumor Necrosis Factor; D053221:TNF-Related Apoptosis-Inducing Ligand; C105190:TNFRSF10A protein, human; C505653:TNFSF10 protein, human; D014409:Tumor Necrosis Factor-alpha; D000077209:Decitabine; D001374:Azacitidine