title: Promoter methylation status of VEGF receptor genes: a possible epigenetic biomarker to anticipate the efficacy of intracellular-acting VEGF-targeted drugs in cancer cells.
abstract: We evaluated whether the inhibitory effects of vascular endothelial growth factor (VEGF)-targeted drugs on the proliferation of cancer cells differed according to VEGF receptor (VEGFR) genes, Flt1 and KDR, promoter methylation status. Five hyper-VEGFR-methylation and six no-VEGFR-methylation cancer cells were used for the present study, together with human umbilical endothelial cells (HUVECs) as a control. No-VEGFR-methylation cancer cells showed higher expression of Flt1 and KDR than hyper-VEGFR-methylation cancer cells. Hyper-VEGFR-methylation cancer cells only showed increased expression and protein levels of Flt1 and KDR after treatment with the demethylase 5-aza-2'-deoxycytidine. Two drugs (a VEGF-specific-antibody, bevacizumab, and a KDR-specific-antibody) targeting extracellular VEGF-VEGFR signaling and two VEGF-specific-tyrosine kinase inhibitors (PTK/ZK and sunitinib) targeting intracellular VEGFR signaling were used in the cell proliferation assay. HUVECs showed dose- and time-dependent proliferation decrease with all tested drugs over a 72 h incubation period. No- or hyper-VEGFR-methylation cancer cells showed no significant proliferation differences after treatment with VEGF-specific-antibody or VEGFR2-specific-antibody. After PTK/ZK or sunitinib treatment, no-VEGFR-methylation cancer cells showed dose- or time-dependent decreases in proliferation. Hyper-VEGFR-methylation cancer cells also showed proliferation inhibition by VEGF-specific-tyrosine kinase inhibitors after demethylation of Flt1 and KDR. Proliferation inhibition synergistically increased after combination of demethylation with PTK/ZK in hyper-VEGF-methylation cancer cells. We observed that intracellular targeting of VEGF-VEGFR signaling could be more effective than extracellular targeting of the pathway in the suppression of proliferation of some cancer cells. In particular, the efficacy of intracellular targeting of VEGF-specific-tyrosine kinase inhibitors might be influenced by the epigenetic alteration of VEGFRs.
authors.affiliation: Department of Neurology, Hospital and School of Medicine, Chungnam National University, Daejon, South Korea.
authors.forename: Jeeyeon
authors.initials: J
authors.lastname: Kim
authors.forename: Junha
authors.initials: J
authors.lastname: Hwang
authors.forename: Hyeseon
authors.initials: H
authors.lastname: Jeong
authors.forename: Hee-Jung
authors.initials: HJ
authors.lastname: Song
authors.forename: Jieun
authors.initials: J
authors.lastname: Shin
authors.forename: Gangmin
authors.initials: G
authors.lastname: Hur
authors.forename: Young Woo
authors.initials: YW
authors.lastname: Park
authors.forename: Suk Hoon
authors.initials: SH
authors.lastname: Lee
authors.forename: Jei
authors.initials: J
authors.lastname: Kim
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology / Q000627:therapeutic use; D014408:Biomarkers, Tumor / Q000235:genetics*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D018899:CpG Islands / Q000235:genetics; D019175:DNA Methylation / Q000187:drug effects / Q000235:genetics*; D044127:Epigenesis, Genetic / Q000187:drug effects; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D061307:Human Umbilical Vein Endothelial Cells / Q000378:metabolism; D006801:Humans; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism; D058990:Molecular Targeted Therapy; D009369:Neoplasms / Q000188:drug therapy* / Q000201:enzymology / Q000235:genetics / Q000473:pathology; D010766:Phosphorylation / Q000187:drug effects; D011401:Promoter Regions, Genetic / Q000235:genetics*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology / Q000627:therapeutic use; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D040262:Receptors, Vascular Endothelial Growth Factor / Q000235:genetics*; D016896:Treatment Outcome; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors* / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D047428:Protein Kinase Inhibitors; D042461:Vascular Endothelial Growth Factor A; D040262:Receptors, Vascular Endothelial Growth Factor; D051057:Proto-Oncogene Proteins c-akt; D048049:Extracellular Signal-Regulated MAP Kinases