Epigenetic dysregulation from chromosomal transit in micronuclei

Area of Science:

• Cell Biology
• Genetics
• Cancer Research

Background:

• Chromosomal instability (CIN) and epigenetic alterations are hallmarks of advanced and metastatic cancers.
• The mechanistic link between CIN and epigenetic changes remains largely unknown.

Purpose of the Study:

• To investigate the mechanistic link between chromosomal instability and epigenetic alterations in cancer.
• To determine if micronuclei formation disrupts histone post-translational modifications (PTMs) and chromatin accessibility.

Main Methods:

• Utilized orthogonal approaches to analyze histone PTMs and chromatin accessibility in cells with induced CIN and micronuclei.
• Examined the impact of micronuclear envelope rupture on histone PTMs.
• Assessed the heritability of epigenetic abnormalities after micronuclei reincorporation.

Main Results:

• Micronuclei formation and rupture profoundly disrupt normal histone PTMs, a conserved phenomenon across species and cell types.
• Micronuclei exhibit significant differences in chromatin accessibility with a positional bias.
• CIN induces widespread epigenetic dysregulation, and chromosomes within micronuclei experience heritable accessibility defects.

Conclusions:

• CIN promotes epigenetic reprogramming and cellular heterogeneity in cancer through disruption of histone PTMs and chromatin accessibility.
• Micronuclei formation is a key driver of epigenetic dysregulation in cancer.
• Understanding this link offers new avenues for cancer therapy targeting epigenetic vulnerabilities.