title: Epigenetic control of group V phospholipase A2 expression in human malignant cells.
abstract: Secreted phospholipases A2 (sPLA2) are suggested to play an important role in inflammation and tumorigenesis. Different mechanisms of epigenetic regulation are involved in the control of group IIA, III and X sPLA2s expression in cancer cells, but group V sPLA2 (GV-PLA2) in this respect has not been studied. Here, we demonstrate the role of epigenetic mechanisms in regulation of GV-PLA2 expression in different cell lines originating from leukaemia and solid cancers. In blood leukocytes from leukaemic patients, levels of GV-PLA2 transcripts were significantly lower in comparison to those from healthy individuals. Similarly, in DU-145 and PC-3 prostate and CAL-51 and MCF-7 mammary cancer cell lines, levels of GV-PLA2 transcripts were significantly lower in relation to those found in normal epithelial cells of prostate or mammary. By sequencing and methylation-specific high-resolution melting (MS-HRM) analyses of bisulphite-modified DNA, distinct CpG sites in the GV-PLA2 promoter region were identified that were differentially methylated in cancer cells in comparison to normal epithelial and endothelial cells. Spearman rank order analysis revealed a significant negative correlation between the methylation degree and the cellular expression of GV-PLA2 (r = -0.697; p = 0.01). The effects of demethylating agent (5-aza-2'-deoxycytidine) and histone deacetylase inhibitor (trichostatin A) on GV-PLA2 transcription in the analysed cells confirmed the importance of DNA methylation and histone modification in the regulation of the GV-PLA2 gene expression in leukaemic, prostate and mammary cancer cell lines. The exposure of tumour cells to human recombinant GV-PLA2 resulted in a reduced colony forming activity of MCF-7, HepG2 and PC-3 cells, but not of DU-145 cells suggesting a cell-type-dependent effect of GV-PLA2 on cell growth. In conclusion, our results suggest that epigenetic mechanisms such as DNA methylation and histone modification play an important role in downregulation of GV-PLA2 expression in cancer cells.
authors.affiliation: Institute of Clinical Chemistry and Laboratory Medicine, Carl Gustav Carus University Hospital, Technical University of Dresden, Fetscherstr. 74, D-01307, Dresden, Germany. Mario.Menschikowski@uniklinikum-dresden.de.
authors.forename: Mario
authors.initials: M
authors.lastname: Menschikowski
authors.affiliation: Institute of Clinical Chemistry and Laboratory Medicine, Carl Gustav Carus University Hospital, Technical University of Dresden, Fetscherstr. 74, D-01307, Dresden, Germany.
authors.forename: Albert
authors.initials: A
authors.lastname: Hagelgans
authors.affiliation: Institute of Clinical Chemistry and Laboratory Medicine, Carl Gustav Carus University Hospital, Technical University of Dresden, Fetscherstr. 74, D-01307, Dresden, Germany.
authors.forename: Brit
authors.initials: B
authors.lastname: Nacke
authors.affiliation: Institute of Clinical Chemistry and Laboratory Medicine, Carl Gustav Carus University Hospital, Technical University of Dresden, Fetscherstr. 74, D-01307, Dresden, Germany.
authors.forename: Carsten
authors.initials: C
authors.lastname: Jandeck
authors.affiliation: Veterans Affairs Greater Los Angeles Healthcare System and University of California at Los Angeles, Los Angeles, CA, USA.
authors.forename: Olga A
authors.initials: OA
authors.lastname: Mareninova
authors.affiliation: Titus Family Department of Clinical Pharmacy, USC School of Pharmacy, Los Angeles, CA, USA.
authors.forename: Liana
authors.initials: L
authors.lastname: Asatryan
authors.affiliation: Institute of Clinical Chemistry and Laboratory Medicine, Carl Gustav Carus University Hospital, Technical University of Dresden, Fetscherstr. 74, D-01307, Dresden, Germany.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Siegert
mesh_terms: D016022:Case-Control Studies; D049109:Cell Proliferation; D002478:Cells, Cultured; D019175:DNA Methylation; D044127:Epigenesis, Genetic; D015972:Gene Expression Regulation, Neoplastic; D054505:Group V Phospholipases A2 / Q000235:genetics*; D006801:Humans; D009369:Neoplasms / Q000235:genetics* / Q000473:pathology*; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013447:Sulfites / Q000737:chemistry
chemical_list: D012333:RNA, Messenger; D013447:Sulfites; D054505:Group V Phospholipases A2; C516299:PLA2G5 protein, human; C042345:hydrogen sulfite
keywords: DNA methylation; Group V sPLA2; Leukaemia; Solid cancer cells