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Modulation of Cytotoxicity by Transcription-Coupled Nucleotide Excision Repair Is Independent of the Requirement for

Claudia Otto1, Graciela Spivak2, Claudia M N Aloisi1

  • 1Department of Health Sciences and Technology, ETH Zurich , 8092 Zurich, Switzerland.

Chemical Research in Toxicology
|January 12, 2017
PubMed

Insights

Transcription-coupled DNA repair reduces cancer cell sensitivity to DNA alkylating agents like acylfulvene, regardless of bioactivation. This DNA repair pathway significantly impacts drug efficacy.

Area of Science:

  • Molecular Biology
  • Cancer Research
  • Pharmacology

Background:

  • Cellular susceptibility to DNA alkylating chemotherapeutic drugs is influenced by bioactivation and DNA repair.
  • The specific roles of these processes in the biological outcomes of metabolically activated DNA alkylating agents are not fully understood.

Purpose of the Study:

  • To evaluate the impact of cellular bioactivation capacity and DNA repair on the cytotoxicity of the DNA alkylating agent acylfulvene (AF).
  • To compare the cytotoxicity and RNA synthesis inhibition by AF and its analogue iso-M0 in cell lines with deficiencies in specific DNA repair pathways.

Main Methods:

  • Utilized a panel of fibroblast cell lines with deficiencies in transcription-coupled nucleotide excision repair (TC-NER) or global genome nucleotide excision repair (GG-NER).
  • Assessed cytotoxicity and RNA synthesis inhibition following treatment with AF and iso-M0.
  • Related experimental data to the inherent bioactivation capacity of each cell type using mRNA levels.
  • Employed siRNA to specifically inactivate TC-NER.

Main Results:

  • Specific inactivation of TC-NER by siRNA significantly increased AF activity in a cancer cell line.
  • Cellular sensitivity to AF was reduced by transcription-coupled DNA repair.
  • This effect was observed independently of the requirement for bioactivation.

Conclusions:

  • Transcription-coupled DNA repair plays a crucial role in determining cellular sensitivity to acylfulvene.
  • Targeting or understanding TC-NER could be a strategy to enhance the efficacy of DNA alkylating agents in cancer therapy.
  • The findings highlight the importance of DNA repair mechanisms in drug response.

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