The nucleotidohydrolases DCTPP1 and dUTPase are involved in the cellular response to decitabine.
Decitabine (5-aza-2'-deoxycytidine, aza-dCyd) is an anti-cancer drug used clinically for the treatment of myelodysplastic syndromes and acute myeloid leukaemia that can act as a DNA-demethylating or genotoxic agent in a dose-dependent manner. On the other hand, DCTPP1 (dCTP pyrophosphatase 1) and dUTPase are two 'house-cleaning' nucleotidohydrolases involved in the elimination of non-canonical nucleotides. In the present study, we show that exposure of HeLa cells to decitabine up-regulates the expression of several pyrimidine metabolic enzymes including DCTPP1, dUTPase, dCMP deaminase and thymidylate synthase, thus suggesting their contribution to the cellular response to this anti-cancer nucleoside. We present several lines of evidence supporting that, in addition to the formation of aza-dCTP (5-aza-2'-deoxycytidine-5'-triphosphate), an alternative cytotoxic mechanism for decitabine may involve the formation of aza-dUMP, a potential thymidylate synthase inhibitor. Indeed, dUTPase or DCTPP1 down-regulation enhanced the cytotoxic effect of decitabine producing an accumulation of nucleoside triphosphates containing uracil as well as uracil misincorporation and double-strand breaks in genomic DNA. Moreover, DCTPP1 hydrolyses the triphosphate form of decitabine with similar kinetic efficiency to its natural substrate dCTP and prevents decitabine-induced global DNA demethylation. The data suggest that the nucleotidohydrolases DCTPP1 and dUTPase are factors involved in the mode of action of decitabine with potential value as enzymatic targets to improve decitabine-based chemotherapy.
Departmento de Bioquímica y Farmacología Molecular, Instituto de Parasitología y Biomedicina Lopez-Neyra, Consejo Superior de Investigaciones Científicas (CSIC), Armilla (Granada), 18016, Spain.
Cristina E
CE
Requena
Departmento de Bioquímica y Farmacología Molecular, Instituto de Parasitología y Biomedicina Lopez-Neyra, Consejo Superior de Investigaciones Científicas (CSIC), Armilla (Granada), 18016, Spain.
Guiomar
G
Pérez-Moreno
Institute of Enzymology, Research Center for Natural Sciences, Hungarian Academy of Science, H-1117 Budapest, Hungary.
András
A
Horváth
Institute of Enzymology, Research Center for Natural Sciences, Hungarian Academy of Science, H-1117 Budapest, Hungary Department of Applied Biotechnology and Food Sciences, University of Technology and Economics, H-1111 Budapest, Hungary.
Beáta G
BG
Vértessy
Departmento de Bioquímica y Farmacología Molecular, Instituto de Parasitología y Biomedicina Lopez-Neyra, Consejo Superior de Investigaciones Científicas (CSIC), Armilla (Granada), 18016, Spain.
Luis M
LM
Ruiz-Pérez
Departmento de Bioquímica y Farmacología Molecular, Instituto de Parasitología y Biomedicina Lopez-Neyra, Consejo Superior de Investigaciones Científicas (CSIC), Armilla (Granada), 18016, Spain dgonzalez@ipb.csic.es avidal@ipb.csic.es.
Dolores
D
González-Pacanowska
Departmento de Bioquímica y Farmacología Molecular, Instituto de Parasitología y Biomedicina Lopez-Neyra, Consejo Superior de Investigaciones Científicas (CSIC), Armilla (Granada), 18016, Spain dgonzalez@ipb.csic.es avidal@ipb.csic.es.
Antonio E
AE
Vidal
D000970:Antineoplastic Agents / Q000494:pharmacology*; D001374:Azacitidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D002460:Cell Line; D002853:Chromatography, Liquid; D000077209:Decitabine; D006367:HeLa Cells; D006801:Humans; D011755:Pyrophosphatases / Q000378:metabolism*; D053719:Tandem Mass Spectrometry
D000970:Antineoplastic Agents; D000077209:Decitabine; D011755:Pyrophosphatases; C020007:dCTP pyrophosphatase; C020020:dUTP pyrophosphatase; D001374:Azacitidine
DCTPP1; XTP3-TPA; dUTPase; decitabine; nucleotide pool