Pharmaceutical Biology (Jan 2017)

4-Nerolidylcatechol: apoptosis by mitochondrial mechanisms with reduction in cyclin D1 at G0/G1 stage of the chronic myelogenous K562 cell line

  • Polyana Lopes Benfica,
  • Renato Ivan de Ávila,
  • Bruna dos Santos Rodrigues,
  • Alane Pereira Cortez,
  • Aline Carvalho Batista,
  • Marilisa Pedroso Nogueira Gaeti,
  • Eliana Martins Lima,
  • Kênnia Rocha Rezende,
  • Marize Campos Valadares

DOI
https://doi.org/10.1080/13880209.2017.1311351
Journal volume & issue
Vol. 55, no. 1
pp. 1899 – 1908

Abstract

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Context: 4-Nerolidylcatechol (4-NRC) has showed antitumor potential through apoptosis. However, its apoptotic mechanisms are still unclear, especially in leukemic cells. Objectives: To evaluate the cytotoxic potential of 4-NRC and its cell death pathways in p53-null K562 leukemic cells. Materials and methods: Cytotoxicity of 4-NRC (4.17–534.5 μM) over 24 h of exposure was evaluated by MTT assay. 4-NRC-induced apoptosis in K562 cells was investigated by phosphatidylserine (PS) externalization, cell cycle, sub-G1, mitochondrial evaluation, cytochrome c, cyclin D1 and intracellular reactive oxygen species (ROS) levels, and caspase activity analysis. Results: IC50 values obtained were 11.40, 27.31, 15.93 and 15.70 μM for lymphocytes, K562, HL-60 and Jurkat cells, respectively. In K562 cells, 4-NRC (27 μM) promoted apoptosis as verified by cellular morphological changes, a significant increase in PS externalization and sub-G1 cells. Moreover, it significantly arrested the cells at the G0/G1 phase due to a reduction in cyclin D1 expression. These effects of 4-NRC also significantly promoted a reduction in mitochondrial activity and membrane depolarization, accumulation of cytosolic cytochrome c and ROS overproduction. Additionally, it triggered an increase in caspases -3/7, -8 and -9 activities. When the cells were pretreated with N-acetyl-l-cysteine ROS scavenger, 4-NRC-induced apoptosis was partially blocked, which suggests that it exerts cytotoxicity though not exclusively through ROS-mediated mechanisms. Discussion and conclusion: 4-NRC has antileukemic properties, inducing apoptosis mediated by mitochondrial-dependent mechanisms with cyclin D1 inhibition. Given that emerging treatment concepts include novel combinations of well-known agents, 4-NRC could offer a promising alternative for chemotherapeutic combinations to maximize tumour suppression.

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