Propolin H from Taiwanese propolis induces G1 arrest in human lung carcinoma cells.

Abstract

Propolis, a natural product collected by honeybee, has been reported to exert a wide spectrum of biological functions. In this study, we have isolated a novel component, namely, propolin H, and investigated its effects in human carcinoma cells. Propolin H inhibited the proliferation of human lung carcinoma cell lines in MTT assay, and a significant G1 arrest was observed to occur in a dose-dependent manner at 24 h of exposure in H460 cells. After treatment with propolin H in H460 cells, the content of the CDK inhibitor p21Waf1/Cip1 protein increased in correlation with the elevation in p53 levels. Western blot analysis of G1 regulatory proteins further revealed a decrease in cyclin-dependent kinase 2 (CDK2) and CDK4 and an increase in cyclin E. The CDKs kinase activities assay showed that propolin H has inhibited CDK2 and CDK4 kinase activities. Accordingly, coimmunoprecipitations revealed an increased association of both CDK2 and CDK4 immunoreactive protein with the p21Waf1/Cip1 protein complex under propolin H-treated conditions. Additionally, we found that propolin H enhanced the expression of p21Waf1/Cip1 in p53-mutant and p53-null lung carcinoma cell lines, following the induction of G1 arrest. Together, these findings suggest that the induction of p21Waf1/Cip1 expression occurred through p53-dependent and -independent pathways in propolin H-treated cells. Propolin H exerts its significantly growth inhibitory effects and may have therapeutic applications.

• Authors: Meng-Shih Weng, Chiung-Ho Liao, Chia-Nan Chen, Chia-Li Wu, Jen-Kun Lin
• Journal: Journal of agricultural and food chemistry (J Agric Food Chem) Vol. 55 Issue 13 Pg. 5289-98 (Jun 27 2007) ISSN: 0021-8561 [Print] United States
• PMID: 17530771 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Flavanones
• Monoterpenes
• propolin H
• Propolis
• Cyclin-Dependent Kinases

Topics

• Cell Division (drug effects)
• Cell Line, Tumor
• Cyclin-Dependent Kinases (antagonists & inhibitors)
• Flavanones (isolation & purification, pharmacology)
• G1 Phase (drug effects)
• Humans
• Lung Neoplasms (pathology)
• Monoterpenes (isolation & purification, pharmacology)
• Propolis (chemistry)
• Taiwan