Hypocrellins and Hypericin induced apoptosis in human tumor cells: a possible role of hydrogen peroxide.

Seyed Mohamed Ali, Soo Khee Chee, Gan Yik Yuen, Malini Olivo

Research output: Contribution to journalArticle

28 Citations (Scopus)

Abstract

We examined whether generation of H2O2 is a critical event for the apoptotic pathway upstream of mitochondrial involvement and caspase-3 protease activation. Perylquinone photosensitizers such as Hypocrellin A (HA), Hypocrellin B (HB) and Hypericin (HY) induced activation of caspase-3 and apoptosis upon photoactivation. Generation of H2O2 was commonly detected after photoactivation within an hour, and scavenging of H2O2 caused cells to fail to undergo apoptosis. Flow cytometry demonstrated that H2O2 production preceded loss of mitochondrial membrane potential (DeltaPsim) in photoactivated cells treated with HA, HB and HY. Then caspase-3 activity was activated, followed by DNA fragmentation. These findings suggest that HA, HB and HY upon photoactivation induce H2O2 generation, which causes (DeltaPsim) and subsequently caspase-3 activation, resulting in apoptosis. These findings suggest that generation of H2O2 by photoactivation of HA, HB and HY causes activation of caspase-3. Therefore, H2O2 may function as a common mediator for apoptosis induced by HA, HB and HY. The present study also demonstrated that upon photoactivation HA, HB and HY induced a decrease in intracellular acidification, glutathione (GSH) depletion and an array of mitochondrial damage together with apoptotic morphological changes in the irradiated cells.

Original languageEnglish
Pages (from-to)461-472
Number of pages12
JournalInternational Journal of Molecular Medicine
Volume9
Issue number5
Publication statusPublished - May 2002
Externally publishedYes

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Hydrogen Peroxide
Caspase 3
Apoptosis
Neoplasms
Photosensitizing Agents
Mitochondrial Membrane Potential
DNA Fragmentation
Glutathione
hypocrellin A
hypericin
hypocrellin B
Flow Cytometry
Peptide Hydrolases

ASJC Scopus subject areas

  • Genetics

Cite this

Hypocrellins and Hypericin induced apoptosis in human tumor cells : a possible role of hydrogen peroxide. / Ali, Seyed Mohamed; Chee, Soo Khee; Yuen, Gan Yik; Olivo, Malini.

In: International Journal of Molecular Medicine, Vol. 9, No. 5, 05.2002, p. 461-472.

Research output: Contribution to journalArticle

Ali, Seyed Mohamed ; Chee, Soo Khee ; Yuen, Gan Yik ; Olivo, Malini. / Hypocrellins and Hypericin induced apoptosis in human tumor cells : a possible role of hydrogen peroxide. In: International Journal of Molecular Medicine. 2002 ; Vol. 9, No. 5. pp. 461-472.
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