Cyclins: roles in mitogenic signaling and oncogenic transformation

Area of Science:

• Cell Biology
• Molecular Oncology
• Biochemistry

Background:

• Cyclins are essential regulatory subunits of kinases controlling cell cycle progression.
• Extracellular signaling pathways frequently target cyclins, leading to deregulation during oncogenesis.
• Cyclin D1 is particularly implicated in cancer, with its abundance modulated by various signaling molecules.

Purpose of the Study:

• To review the roles of cyclins, focusing on cyclin D1, as targets of extracellular signaling.
• To elucidate how receptor tyrosine kinases and adhesion molecules influence cyclin D1 levels.
• To highlight the importance of cyclin D1 in oncogenesis and its dependence on signaling pathways.

Main Methods:

• Review of existing literature on cyclin regulation and oncogenesis.
• Analysis of signaling pathways affecting cyclin D1 at transcriptional, translational, and protein stability levels.
• Examination of the interplay between oncogenes (e.g., Ras, Neu/ErbB2) and cyclin D1.

Main Results:

• Extracellular signals modulate cyclin D1 abundance through multiple regulatory mechanisms.
• Cyclin E-Cdk2 activity is often regulated independently of cyclin E abundance.
• Oncogenic pathways like Ras and Neu/ErbB2 rely on cyclin D1 for their function.

Conclusions:

• Cyclin D1 plays a critical role in mediating the effects of growth factor and adhesion signaling in both normal and cancerous cells.
• Understanding cyclin regulation by extracellular signals is vital for cancer biology research.
• Targeting cyclin D1 pathways may offer therapeutic strategies for neoplastic diseases.