Evidence for improved DNA repair in the long-lived bowhead whale

Area of Science:

• Genomics
• Mammalian Biology
• Cancer Research

Background:

• Bowhead whales exhibit exceptional longevity (over 200 years) and large body size, yet have a low incidence of cancer, a phenomenon known as Peto's paradox.
• Understanding the mechanisms behind this cancer resistance is crucial for insights into aging and oncology.

Purpose of the Study:

• To investigate the cellular mechanisms underlying the bowhead whale's remarkable cancer resistance.
• To identify key genetic or molecular factors contributing to genome stability and longevity in this species.

Main Methods:

• Comparative analysis of oncogenic hits required for malignant transformation in bowhead whale versus human fibroblasts.
• Assessment of DNA double-strand break repair capacity, fidelity, and mutation rates in bowhead whale cells.
• Investigation of the role of cold-inducible RNA-binding protein (CIRBP) in DNA repair and cellular function, including in vitro assays and Drosophila models.

Main Results:

• Bowhead whale fibroblasts required fewer oncogenic hits for transformation than human fibroblasts.
• Bowhead whale cells demonstrated enhanced DNA double-strand break repair (non-homologous end joining and homologous recombination) and lower mutation rates.
• Bowhead whale CIRBP significantly improved DNA repair in human cells, reduced DNA damage markers, and extended lifespan and radiation resistance in Drosophila.

Conclusions:

• The bowhead whale's cancer resistance is attributed to highly efficient DNA repair mechanisms, rather than solely relying on additional tumor suppressor genes.
• The protein CIRBP plays a critical role in maintaining genome integrity through enhanced DNA repair, contributing to the species' longevity and low cancer incidence.
• This strategy of faithful DNA repair, rather than cell elimination, offers a novel perspective on aging and cancer prevention.