Baicalein induces a dual growth arrest by modulating multiple cell cycle regulatory molecules

Area of Science:

• Cardiovascular Biology
• Molecular Pharmacology
• Plant-derived Compounds

Background:

• Baicalein is a flavonoid found in Scutellaria baicalensis Georgi.
• Previous studies indicate baicalein inhibits cell proliferation in various cell types.
• The specific effects on heart endothelial cells require further investigation.

Purpose of the Study:

• To investigate the impact of baicalein on primary cultured rat heart endothelial cell growth.
• To elucidate the underlying molecular mechanisms of baicalein-induced growth modulation.

Main Methods:

• Primary cultured rat heart endothelial cells were treated with 100-microM baicalein.
• Cell proliferation was assessed over a 5-day incubation period.
• Expression levels and kinase activities of cell cycle regulatory proteins (cyclins, CDKs, p53, p21, p15) were evaluated.

Main Results:

• Baicalein treatment led to nearly complete inhibition of endothelial cell proliferation after 5 days.
• Baicalein induced G1 and G2 cell cycle arrest.
• Key proteins involved in cell cycle progression, including cyclin D2, cyclin A, Cdk1, and Cdk2, were down-regulated, while p15(Ink4B), p21(CIP1/Waf1), p53, and cyclin E were up-regulated.

Conclusions:

• Baicalein effectively inhibits rat heart endothelial cell proliferation.
• The mechanism involves G1 and G2 cell cycle arrest.
• Modulation of cyclin/Cdk complexes and key regulatory proteins (p53, p21, p15) underlies baicalein's anti-proliferative effects in these cells.