Molecular Links between the Circadian Clock and the Cell Cycle

Area of Science:

• Molecular Biology
• Chronobiology
• Cancer Research

Background:

• The circadian clock regulates cell division in healthy organisms.
• Bidirectional coupling exists between the circadian clock and cell cycle in mouse fibroblasts.
• Cancer cells exhibit deregulated proliferation and altered circadian gene expression.

Purpose of the Study:

• To review the molecular organization of the circadian clock and cell cycle.
• To examine the reciprocal interaction between these systems in normal and cancer cells.
• To highlight the importance of understanding this interplay for cancer chronotherapy.

Main Methods:

• Literature review of molecular mechanisms.
• Analysis of existing single-cell studies on circadian clock and cell cycle coupling.
• Synthesis of information on normal versus cancer cell interactions.

Main Results:

• The circadian clock and cell cycle are robustly phase-coupled in healthy cells, leading to timed mitosis and DNA replication.
• Cancer cells often display dysregulated cell proliferation and disrupted circadian gene expression.
• The interplay between these oscillators in cancer cells remains largely unknown.

Conclusions:

• Understanding the coupling of the circadian clock and cell cycle in cancer is crucial.
• This knowledge is instrumental for optimizing cancer chronotherapy by exploiting mitotic asynchrony.
• Predicting optimal treatment timing requires insight into host-versus-malignant cell mitotic schedules.