Formaldehyde-induced genome instability is suppressed by an XPF-dependent pathway

Area of Science:

• Genetics
• Molecular Biology
• Toxicology

Background:

• Formaldehyde is a widely used chemical linked to cancer.
• Formaldehyde induces DNA-protein crosslinks (DPCs), triggering DNA repair pathways like nucleotide excision repair (NER).
• The precise cellular and genetic changes leading to formaldehyde's genotoxic effects remain unclear.

Purpose of the Study:

• To investigate genes modulating formaldehyde's cytotoxic effects.
• To determine the role of NER pathway components, specifically XPF, in cellular responses to formaldehyde.
• To elucidate the mechanisms underlying formaldehyde-induced DNA damage and genomic instability.

Main Methods:

• Tested five NER-deficient Chinese Hamster Ovary (CHO) cell lines for sensitivity to formaldehyde.
• Performed cell cycle analysis on formaldehyde-treated XPF-deficient cells.
• Quantified DNA double-strand breaks (DSBs), chromosomal aberrations, and radial formation.

Main Results:

• XPF- and ERCC1-deficient cells exhibited heightened sensitivity to formaldehyde compared to wild-type cells.
• Formaldehyde-treated XPF-deficient cells displayed immediate G2/M arrest, altered ploidy, and apoptosis.
• Elevated DSBs, chromosomal breaks, and radial formation were observed in XPF-deficient cells; DSBs were replication-dependent but XPF-independent, with delayed repair in XPF-deficient cells.

Conclusions:

• An XPF-dependent pathway is crucial for mitigating sensitivity to formaldehyde-induced DNA damage.
• XPF deficiency leads to increased genomic instability and reduced cell viability following formaldehyde exposure.
• Formaldehyde exposure induces centrosome, microtubule, and nuclear abnormalities even in repair-proficient cells.