title: Citrate enhances in vitro metastatic behaviours of PC-3M human prostate cancer cells: status of endogenous citrate and dependence on aconitase and fatty acid synthase.
abstract: Prostate is a unique organ that produces and releases large amounts of citrate. This is reduced significantly in cancer and it is possible that citrate is (re)taken up and used as a metabolite to enhance cellular activity. The main purpose of this study was to determine how cytosolic citrate might affect in vitro metastatic cell behaviours (lateral motility, endocytosis and adhesion). Normal (PNT2-C2) and metastatic (PC-3M) human prostate cancer cells were used in a comparative approach. As regards intermediary metabolic enzymes, aconitase and fatty acid synthase, already implicated in prostate cancer, were evaluated. The level of intracellular citrate was significantly higher in PNT2-C2 cells under both control conditions and following preincubation in extracellular citrate. Supply of exogenous citrate enhanced endocytosis, lateral motility, decreased cell adhesion of PC-3M cells but failed to produce any effect on normal cells. Real-time PCR measurements showed that the mRNA levels of mitochondrial and cytosolic aconitases and fatty acid synthase were significantly higher in PC-3M cells. Correspondingly, aconitase activity was also higher in PC-3M cells. Using cerulenin (an inhibitor of fatty acid synthase), oxalomalate and fluorocitrate (inhibiting aconitases), we investigated the dependence of citrate-induced down-regulation of cellular adhesion on aconitase and fatty acid synthase activities. It was concluded: (1) that strongly metastatic PC-3M cells stored less/utilised more cytosolic citrate than the normal PNT2-C2 cells and (2) that cancer cells could metabolise cytoplasmic citrate via aconitase and fatty acid synthase to enhance their metastatic behaviour.
authors.affiliation: Divison of Cell & Molecular Biology, Neuroscience Solutions to Cancer Research Group, Sir Alexander Fleming Building, Imperial College London, South Kensington Campus, London SW7 2AZ, UK. m.mycielska@imperial.ac.uk
authors.forename: Maria E
authors.initials: ME
authors.lastname: Mycielska
authors.forename: Timothy P
authors.initials: TP
authors.lastname: Broke-Smith
authors.forename: Christopher P
authors.initials: CP
authors.lastname: Palmer
authors.forename: Rachel
authors.initials: R
authors.lastname: Beckerman
authors.forename: Theodoros
authors.initials: T
authors.lastname: Nastos
authors.forename: Kamil
authors.initials: K
authors.lastname: Erguler
authors.forename: Mustafa B A
authors.initials: MB
authors.lastname: Djamgoz
mesh_terms: D000154:Aconitate Hydratase / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport; D002448:Cell Adhesion / Q000187:drug effects; D045744:Cell Line, Tumor; D019343:Citric Acid / Q000378:metabolism* / Q000494:pharmacology; D003600:Cytosol / Q000378:metabolism; D064429:Fatty Acid Synthases / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008297:Male; D009362:Neoplasm Metastasis; D011471:Prostatic Neoplasms / Q000201:enzymology* / Q000378:metabolism / Q000473:pathology*; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; D019343:Citric Acid; D064429:Fatty Acid Synthases; D000154:Aconitate Hydratase