Cadmium disrupts the DNA damage response by destabilizing RNF168

Area of Science:

• Environmental Toxicology
• Molecular Biology
• Cancer Research

Background:

• Cadmium (Cd) is a toxic environmental and occupational exposure agent.
• Cd exposure is linked to cellular proliferation and tumorigenesis through poorly understood mechanisms.
• The role of Cd in the DNA damage response (DDR) is largely unexplored.

Purpose of the Study:

• To investigate the impact of Cadmium on the DNA damage response.
• To elucidate the molecular mechanisms by which Cd may contribute to carcinogenesis.

Main Methods:

• Assessing DNA double-strand breaks (DSBs) and ubiquitination signals.
• Evaluating the recruitment of DNA repair proteins (53BP1, BRCA1) to DSBs.
• Investigating the effect of Cd on the E3 ubiquitin ligase RNF168 and the ubiquitin-proteasome pathway.

Main Results:

• Cd exposure induced extensive DNA double-strand breaks (DSBs).
• Cd prevented ubiquitination signaling at DSBs and compromised 53BP1 and BRCA1 recruitment.
• Cd directly bound to RNF168, promoting its degradation and inhibiting its activity, thus disrupting DSB signaling.

Conclusions:

• Cadmium disrupts the DNA damage response by targeting RNF168, leading to impaired DSB repair.
• This mechanism of RNF168 inhibition and subsequent disruption of DNA repair pathways represents a novel pathway for Cd-induced carcinogenesis.