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Redox modulation of oxidatively-induced DNA damage.pdf (6.51 MB)

Redox modulation of oxidatively-induced DNA damage by ascorbate enhances both in vitro and ex-vivo DNA damage formation and cell death in melanoma cells.

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posted on 2024-02-09, 11:54 authored by Hishyar A Najeeb, Timi Sanusi, Gerald Saldanha, Karen Brown, Marcus S Cooke, George Dd Jones

Elevated genomic instability in cancer cells suggests a possible model-scenario for their selective killing via the therapeutic delivery of well-defined levels of further DNA damage. To examine this scenario, this study investigated the potential for redox modulation of oxidatively-induced DNA damage by ascorbate in malignant melanoma (MM) cancer cells, to selectively enhance both DNA damage and MM cell killing. DNA damage was assessed by Comet and ɣH2AX assays, intracellular oxidising species by dichlorofluorescein fluorescence, a key antioxidant enzymatic defence by assessment of catalase activity and cell survival was determined by clonogenic assay. Comet revealed that MM cells had higher endogenous DNA damage levels than normal keratinocytes (HaCaT cells); this correlated MM cells having higher intracellular oxidising species and lower catalase activity, and ranked with MM cell melanin pigmentation. Comet also showed MM cells more sensitive towards the DNA damaging effects of exogenous H2O2, and that ascorbate further enhanced this H2O2-induced damage in MM cells; again, with MM cell sensitivity to induced damage ranking with degree of cell pigmentation. Furthermore, cell survival data indicated that ascorbate enhanced H2O2-induced clonogenic cell death selectively in MM cells whilst protecting HaCaT cells. Finally, we show that ascorbate serves to enhance the oxidising effects of the MM therapeutic drug Elesclomol in both established MM cells in vitro and primary cell cultures ex vivo. Together, these results suggest that ascorbate selectively enhances DNA damage and cell-killing in MM cells. This raises the option of incorporating ascorbate into clinical oxidative therapies to treat MM.

Funding

National Institute for Health and Care Research and Cancer Research UK through Experimental Cancer Medicine Centre (ECMC) awards [C10604/A25151]

Kurdistan Regional Government, Iraq for funding the PhD studentship awarded to HAN and the University of Leicester's Medical School LINK initiative in supporting TS's involvement in this study

History

Author affiliation

Leicester cancer research centre, University of Leicester

Version

  • VoR (Version of Record)

Published in

Free radical biology & medicine

Volume

213

Pagination

309 - 321

Publisher

Elsevier

issn

0891-5849

eissn

1873-4596

Copyright date

2024

Available date

2024-02-09

Spatial coverage

United States

Language

eng

Deposited by

Mrs Louise Thompson

Deposit date

2024-02-06

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