Activation of nuclear factor-kappa B signalling promotes cellular senescence

Area of Science:

• Cellular and Molecular Biology
• Oncology
• Genetics

Background:

• Cellular senescence is a critical tumor-suppressive mechanism involving irreversible cell cycle arrest.
• The specific signaling pathways driving senescence and their clinical relevance remain largely undefined.
• Senescence can be triggered by telomere shortening, oncogene activation, and oxidative stress.

Purpose of the Study:

• To identify differentially expressed genes during senescence.
• To elucidate the underlying signaling pathways involved in senescence.
• To investigate the relationship between senescence, cancer gene signatures, and NF-κB signaling.

Main Methods:

• Genome-wide expression profiling of human fibroblasts undergoing senescence.
• Genetic complementation to identify senescence-specific gene expression changes.
• Analysis of gene expression overlap with cancer meta-signatures and NF-κB targets.

Main Results:

• Identified 816 upregulated and 961 downregulated genes during senescence, with expression reversal upon bypassing senescence.
• Nearly 50% of genes upregulated in cancer were downregulated in senescent cells.
• 65 upregulated and 26 downregulated genes were identified as NF-κB targets, suggesting NF-κB pathway activation during senescence.

Conclusions:

• Activation of the p16-pRB and p53-p21 tumor suppressor pathways induces significant changes in gene expression during senescence.
• Senescence is strongly associated with NF-κB pathway activation, which plays a causal role in promoting cell cycle arrest.
• Understanding senescence-associated gene expression and NF-κB signaling offers insights into cellular aging and malignant transformation.