title: Methylation of death-associated protein kinase is associated with cetuximab and erlotinib resistance.
abstract: Anti-EGFR therapy is among the most promising molecular targeted therapies against cancer developed in the past decade. However, drug resistance eventually arises in most, if not all, treated patients. Emerging evidence has linked epigenetic changes, such as DNA methylation at CpG islands, to the development of resistance to multiple anticancer drugs. In addition, genes that are differentially methylated have increasingly been appreciated as a source of clinically relevant biomarker candidates. To identify genes that are specifically methylated during the evolution of resistance to anti-EGFR therapeutic agents, we performed a methylation-specific array containing a panel of 56 genes that are commonly known to be regulated through promoter methylation in two parental non-small cell lung cancer (NSCLC) and head and neck squamous cell carcinoma (HNSCC) cell lines and their resistant derivatives to either erlotinib or cetuximab. We found that death-associated protein kinase (DAPK) was hypermethylated in drug-resistant derivatives generated from both parental cell lines. Restoration of DAPK into the resistant NSCLC cells by stable transfection re-sensitized the cells to both erlotinib and cetuximab. Conversely, siRNA-mediated knockdown of DAPK induced resistance in the parental sensitive cells. These results demonstrate that DAPK plays important roles in both cetuximab and erlotinib resistance, and that gene silencing through promoter methylation is one of the key mechanisms of developed resistance to anti-EGFR therapeutic agents. In conclusion, DAPK could be a novel target to overcome resistance to anti-EGFR agents to improve the therapeutic benefit, and further evaluation of DAPK methylation as a potential biomarker of drug response is needed.
authors.affiliation: Department of Otolaryngology and Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Takenori
authors.initials: T
authors.lastname: Ogawa
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Liggett
authors.forename: Anatoliy A
authors.initials: AA
authors.lastname: Melnikov
authors.forename: Constance L
authors.initials: CL
authors.lastname: Monitto
authors.forename: Daniela
authors.initials: D
authors.lastname: Kusuke
authors.forename: Kiyoto
authors.initials: K
authors.lastname: Shiga
authors.forename: Toshimitsu
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Akira
authors.initials: A
authors.lastname: Horii
authors.forename: Aditi
authors.initials: A
authors.lastname: Chatterjee
authors.forename: Victor V
authors.initials: VV
authors.lastname: Levenson
authors.forename: Wayne M
authors.initials: WM
authors.lastname: Koch
authors.forename: David
authors.initials: D
authors.lastname: Sidransky
authors.forename: Xiaofei
authors.initials: X
authors.lastname: Chang
mesh_terms: D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000494:pharmacology*; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents / Q000737:chemistry / Q000494:pharmacology; D051017:Apoptosis Regulatory Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D002289:Carcinoma, Non-Small-Cell Lung / Q000201:enzymology / Q000473:pathology; D002294:Carcinoma, Squamous Cell / Q000201:enzymology / Q000473:pathology; D045744:Cell Line, Tumor; D000068818:Cetuximab; D019175:DNA Methylation / Q000187:drug effects*; D064550:Death-Associated Protein Kinases; D019008:Drug Resistance, Neoplasm; D000069347:Erlotinib Hydrochloride; D006258:Head and Neck Neoplasms / Q000201:enzymology / Q000473:pathology; D006801:Humans; D008175:Lung Neoplasms / Q000201:enzymology / Q000473:pathology; D011401:Promoter Regions, Genetic; D011799:Quinazolines / Q000737:chemistry / Q000494:pharmacology*; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; D051017:Apoptosis Regulatory Proteins; D011799:Quinazolines; D034741:RNA, Small Interfering; D000069347:Erlotinib Hydrochloride; D064550:Death-Associated Protein Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D000068818:Cetuximab