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Continuous Fluorescence-Based Endonuclease-Coupled DNA Methylation Assay to Screen for DNA Methyltransferase Inhibitors
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DNA-Demethylating Agents Target Colorectal Cancer Cells by Inducing Viral Mimicry by Endogenous Transcripts

David Roulois1, Helen Loo Yau2, Rajat Singhania1

  • 1Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 2M9, Canada.

Cell
|August 29, 2015
PubMed

Insights

Low-dose 5-AZA-CdR targets colorectal cancer-initiating cells (CICs) by inducing viral mimicry. This activates the MDA5/MAVS/IRF7 pathway, offering a new therapeutic strategy for colorectal cancer.

Area of Science:

  • Oncology
  • Molecular Biology
  • Immunology

Background:

  • DNA-demethylating agents show anti-tumor effects through unclear mechanisms.
  • Colorectal cancer-initiating cells (CICs) are crucial for tumor growth and recurrence.

Purpose of the Study:

  • To elucidate the mechanism of action for low-dose 5-AZA-CdR in colorectal cancer.
  • To investigate the role of viral mimicry and RNA recognition pathways in 5-AZA-CdR efficacy.

Main Methods:

  • Experimental and bioinformatics analyses in colorectal cancer cells.
  • Investigated the effects of 5-AZA-CdR on CICs, dsRNA induction, and the MDA5/MAVS/IRF7 pathway.
  • Disruption of key pathway components (MDA5, MAVS, IRF7) and dsRNA transfection experiments.

Main Results:

  • Low-dose 5-AZA-CdR induces viral mimicry in colorectal CICs.
  • This involves dsRNA production from endogenous retroviral elements, activating the MDA5/MAVS/IRF7 pathway.
  • Disrupting this pathway abrogates 5-AZA-CdR's targeting of CICs and its long-term growth inhibition.

Conclusions:

  • The anti-tumor mechanism of DNA-demethylating agents involves inducing viral mimicry and activating the MDA5/MAVS/IRF7 pathway.
  • This pathway is critical for 5-AZA-CdR's efficacy against colorectal CICs.
  • The MDA5/MAVS/IRF7 pathway represents a potential therapeutic target for colorectal cancer treatment.

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