Autor(es):
Rossato, Luciana Grazziotin 
; Costa, Vera Marisa ; Vilas-Boas, Vânia ; Bastos, Maria de Lourdes ; Rolo, Anabela ; Palmeira, C. M. ; Remião, Fernando
Data: 2013
Identificador Persistente: http://hdl.handle.net/10316/25617
Origem: Estudo Geral - Universidade de Coimbra
Assunto(s): Mitoxantrone; Cardiotoxicity; Energetic failure; Oxidative stress; Energetic imbalance
Descrição
Mitoxantrone (MTX) is a chemotherapeutic
agent that emerged as an alternative to anthracycline therapy.
However, MTX also causes late cardiotoxicity, being
oxidative stress and mitochondrial-impaired function proposed
as possible mechanisms. This work aimed to investigate
the relevance of these mechanisms to the MTX
toxicity in H9c2 cells, using therapeutic concentrations. The
observed cytotoxicity of MTX was time and concentration
dependent in both lactate dehydrogenase leakage assay and
MTT reduction assay. Two therapeutic concentrations (100
nM and 1 lM) and three time points were selected (24, 48,
and 96 h) for further studies. Both MTX concentrations
caused a significant increase in caspase-3 activity, which
was not prevented by inhibiting MTX CYP450-metabolism.
Significant decreases were observed in the total and reduced
glutathione levels only in MTX 100 nM at 96 h; however,
neither alterations in oxidized glutathione nor increases in
the malondialdehyde levels were observed at any time or
concentrations tested. On the other hand, changes in the
intracellular ATP levels, mitochondrial membrane potential,
and intracellular calcium levels were observed in both
concentrations and all time tested. Noteworthy, decreased
levels of ATP-synthase expression and activity and
increases in the reactive species generation were observed
at 96 h in both working concentrations. However, the radical
scavenger N-acetylcysteine or the mitochondrial function
enhancer L-carnitine did not prevent MTX cytotoxicity.
Thus, this work evidenced the early MTX-induced energetic
crisis as a possible key factor in the cell injury. This work received financial support from
‘‘Fundação para a Ciência e Tecnologia (FCT),’’ Portugal (EXPL/
DTP-FTO/0290/2012) and by ‘‘Fundo Comunitário Europeu’’
(FEDER) under the frame of ‘‘Eixo I do Programa Operacional Fatores
de Competitividade (POFC) do QREN’’ (COMPETE: FCOMP-
01-0124-FEDER-027749). The work was also supported by FCT
within the framework of Strategic Projects for Scientific Research
Units of R&D (project PEst-C/EQB/LA0006/2011). LGR and VVB
thank FCT for their PhD Grant (SFRH/BD/63473/2009 and SFRH/
BD/82556/2011, respectively) and VMC thank FCT for her Post-doc
Grant (SFRH/BPD/63746/2009).
