Cytoprotective effect of 2-carbomethoxy-2,3-epoxy-3-prenyl-1,4-naphthoquinone (CMEP-NQ) is mediated by the inhibition of BAK-dependent mitochondrial apoptosis pathway

PLoS One. 2018 Oct 1;13(10):e0204585. doi: 10.1371/journal.pone.0204585. eCollection 2018.

Abstract

The inhibitory mechanism of 2-carbomethoxy-2,3-epoxy-3-prenyl-1,4-naphthoquinone (CMEP-NQ) against apoptosis induced by the microtubule-damaging agents (MDAs), nocodazole (NOC) and 2-methoxyestradiol (2-MeO-E2), or a DNA-damaging agent (DDA), camptothecin (CPT) were investigated in human Jurkat T cell clones (J/Neo and J/BCL-XL cells). Treatment of J/Neo cells with NOC, 2-MeO-E2, or CPT caused cytotoxicity and apoptotic DNA fragmentation but these events were significantly attenuated in the presence of CMEP-NQ. Although not only MDA (NOC or 2-MeO-E2)-induced mitotic arrest, CDK1 activation, and BCL-2, BCL-XL and BIM phosphorylation, but also DDA (CPT)-induced S-phase arrest and ATM-CHK1/CHK2-p53 pathway activation were not or were barely affected in the presence of CMEP-NQ, the levels of anti-apoptotic BAG3 and MCL-1, which were markedly downregulated after MDA- or DDA-treatment, were rather elevated by CMEP-NQ. Under the same conditions, MDA- or DDA-induced mitochondrial apoptotic events including BAK activation, mitochondrial membrane potential (Δψm) loss, caspase-9 activation, and PARP cleavage were significantly inhibited by CMEP-NQ. While MDA- or DDA-induced sub-G1 peak and Δψm loss were abrogated in J/BCL-XL cells, MDA-induced mitotic arrest and DDA-induced S-arrest were more apparent in J/BCL-XL cells than in J/Neo cells. Simultaneously, the induced cell cycle arrest in J/BCL-XL cells was not significantly disturbed by CMEP-NQ. MDA- or DDA-treatment caused intracellular reactive oxygen species (ROS) production; however, MDA- or DDA-induced ROS production was almost completely abrogated in J/BCL-XL cells. MDA- or DDA-induced ROS production in J/Neo cells was significantly suppressed by CMEP-NQ, but the suppressive effect was hardly observed in J/BCL-XL cells. Together, these results show that CMEP-NQ efficiently protects Jurkat T cells from apoptotic cell death via the elevation of BAG3 and MCL-1 levels, which results in the inhibition of intrinsic BAK-dependent mitochondrial apoptosis pathway, as does the overexpression of BCL-XL.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 2-Methoxyestradiol / pharmacology
  • Apoptosis / drug effects*
  • Cell Cycle Checkpoints / drug effects
  • Cytoprotection / drug effects*
  • DNA Fragmentation / drug effects
  • Gene Expression Regulation / drug effects
  • Humans
  • Jurkat Cells
  • Membrane Potential, Mitochondrial / drug effects
  • Mitochondria / drug effects*
  • Mitochondria / pathology
  • Naphthoquinones / pharmacology*
  • Nocodazole / pharmacology
  • Reactive Oxygen Species / metabolism
  • bcl-2 Homologous Antagonist-Killer Protein / metabolism*
  • bcl-X Protein / metabolism

Substances

  • 2-carbomethoxy-2,3-epoxy-3-prenyl-1,4-naphthoquinone
  • Naphthoquinones
  • Reactive Oxygen Species
  • bcl-2 Homologous Antagonist-Killer Protein
  • bcl-X Protein
  • 2-Methoxyestradiol
  • Nocodazole

Grants and funding

This study was supported by a grant from the National Research Foundation of Korea funded by the Korean government (NRF-2016R1A2B4016101). The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.