Goniothalamin-induced oxidative stress, DNA damage and apoptosis via caspase-2 independent and Bcl-2 independent pathways in Jurkat T-cells

S. H. Inayat-Hussain, Chan Kok Meng, Nor Fadilah Rajab, L. B. Din, S. C. Chow, A. Kizilors, F. Farzaneh, G. T. Williams

Research output: Contribution to journalArticle

44 Citations (Scopus)

Abstract

Goniothalamin (GTN) isolated from Goniothalamus sp. has been demonstrated to induce apoptosis in a variety of cancer cell lines including Jurkat T leukemia cells. However, the mechanism of GTN-induced apoptosis upstream of mitochondria is still poorly defined. In this study, GTN caused a decrease in GSH with an elevation of reactive oxygen species as early as 30 min and DNA damage as assessed by Comet assay. Analysis using topoisomerase II processing of supercoiled pBR 322 DNA showed that GTN caused DNA damage via a topoisomerase II-independent pathway suggesting that cellular oxidative stress may contribute to genotoxicity. A 12-fold increase of caspase-2 activity was observed in GTN-treated Jurkat cells after 4 h treatment and this was confirmed using Western blotting. Although the caspase-2 inhibitor Z-VDVAD-FMK inhibited the proteolytic activity of caspase-2, apoptosis ensued confirming that caspase-2 activity was not crucial for GTN-induced apoptosis. However, GTN-induced apoptosis was completely abrogated by N-acetylcysteine further confirming the role of oxidative stress. Since cytochrome c release was observed as early as 1 h without any appreciable change in Bcl-2 protein expression, we further investigated whether overexpression of Bcl-2 confers resistance in GTN-induced cytotoxicity. Using a panel of Jurkat Bcl-2 transfectants, GTN cytotoxicity was not abrogated in these cells. In conclusion, GTN induces DNA damage and oxidative stress resulting in apoptosis which is independent of both caspase-2 and Bcl-2.

Original languageEnglish
Pages (from-to)108-114
Number of pages7
JournalToxicology Letters
Volume193
Issue number1
DOIs
Publication statusPublished - 1 Mar 2010

Fingerprint

Caspase 2
Oxidative stress
Jurkat Cells
T-cells
DNA Damage
Oxidative Stress
Apoptosis
T-Lymphocytes
DNA
Type II DNA Topoisomerase
Cytotoxicity
Goniothalamus
goniothalamin
T-Cell Leukemia
Mitochondria
Caspase Inhibitors
Comet Assay
Acetylcysteine
Cytochromes c
Assays

Keywords

  • Bcl-2
  • Caspase-2
  • DNA damage
  • Goniothalamin
  • Oxidative stress

ASJC Scopus subject areas

  • Toxicology

Cite this

Goniothalamin-induced oxidative stress, DNA damage and apoptosis via caspase-2 independent and Bcl-2 independent pathways in Jurkat T-cells. / Inayat-Hussain, S. H.; Kok Meng, Chan; Rajab, Nor Fadilah; Din, L. B.; Chow, S. C.; Kizilors, A.; Farzaneh, F.; Williams, G. T.

In: Toxicology Letters, Vol. 193, No. 1, 01.03.2010, p. 108-114.

Research output: Contribution to journalArticle

Inayat-Hussain, S. H. ; Kok Meng, Chan ; Rajab, Nor Fadilah ; Din, L. B. ; Chow, S. C. ; Kizilors, A. ; Farzaneh, F. ; Williams, G. T. / Goniothalamin-induced oxidative stress, DNA damage and apoptosis via caspase-2 independent and Bcl-2 independent pathways in Jurkat T-cells. In: Toxicology Letters. 2010 ; Vol. 193, No. 1. pp. 108-114.
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