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Treatment of Human HeLa Cells with Black Raspberry Extracts Enhances the Removal of DNA Lesions by the Nucleotide

Ana H Sales1, Marina Kolbanovskiy1, Nicholas E Geacintov1

  • 1Department of Chemistry, New York University, New York, NY 10003, USA.

Antioxidants (Basel, Switzerland)
|November 11, 2022
PubMed

Insights

Black raspberries (BRB) enhance DNA repair capacity, specifically nucleotide excision repair (NER), in human cells. This suggests BRB

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Cancer Research

Background:

  • Dietary intake of freeze-dried black raspberries (BRB) has been shown to inhibit DNA damage and carcinogenesis in animal models.
  • The precise mechanisms by which BRB exerts its protective effects are not fully understood.
  • DNA repair capacity is crucial for maintaining genomic stability and preventing cancer development.

Purpose of the Study:

  • To investigate whether black raspberry extracts (BRBE) enhance DNA repair capacity in vitro.
  • To determine the effect of BRBE on specific DNA repair pathways, including nucleotide excision repair (NER) and base excision repair (BER).
  • To assess the impact of BRBE on the expression of key DNA repair proteins.

Main Methods:

  • Human HeLa cell extracts were used as an in vitro system to assess DNA repair activity.
  • Nucleotide excision repair (NER) of a benzo[a]pyrene-derived deoxyguanosine adduct (BP-dG) and an oxidative lesion (guanidinohydantoin, Gh) was measured.
  • Base excision repair (BER) activity for Gh was also assessed.
  • Western Blot analysis was performed to quantify the expression levels of NER factors XPA, XPB, and XPD.

Main Results:

  • BRBE pre-treatment significantly enhanced NER of BP-dG by approximately 24%.
  • BRBE also enhanced NER of the oxidative lesion Gh by approximately 24%, while BER activity was only modestly enhanced (~6%).
  • Western Blot analysis revealed increased expression of NER factors XPA (~73%) and XPB (~55%), with a smaller increase in XPD (<14%).

Conclusions:

  • Black raspberry extracts significantly enhance the nucleotide excision repair (NER) of both bulky and non-bulky DNA lesions.
  • The observed enhancement in NER activity correlates with increased expression of critical NER factors, specifically XPA and XPB.
  • These findings suggest that enhanced DNA repair capacity, particularly NER, is a key mechanism underlying the chemopreventive effects of black raspberries.
Keywords:
black raspberry extractsbulky benzo[a]pyrene DNA adductsexpression of nucleotide excision repair proteinsoxidative DNA damage and repairwestern blots

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