[Frontiers in Bioscience 16, 1060-1068, January 1, 2011]

Apigenin induces apoptosis and impairs head and neck carcinomas EGFR/ErbB2 signaling

Laura Masuelli1, Laura Marzocchella2, Alessandro Quaranta3, Camilla Palumbo2, Giorgio Pompa3, Valerio Izzi2, Antonella Canini4, Andrea Modesti2, Fabio Galvano5, Roberto Bei2

1Department of Experimental Medicine, University of Rome, Sapienza, Rome, Italy, 2Department of Experimental Medicine and Biochemical Sciences, University of Rome "Tor Vergata", Rome, Italy, 3Department of Dental Sciences University of Rome, Sapienza, Rome, Italy, 4Department of Biology, University of Rome, Tor Vergata, Rome, Italy, 5Department of Biological Chemistry, Medical Chemistry and Molecular Biology, University of Catania, Catania, Italy

TABLE OF CONTENTS

1. Abstract
2. Introduction
3. Materials and methods
3.1. Reagents
3.2. Cell lines and treatments
3.3. Sulforhodamine B (SRB) cell proliferation assay
3.4. FACS analysis
3.5. In situ detection of apoptosis
3.6. Preparation of cell lysates and Western Blotting
3.7. Statistical analysis
4. Results
5. Discussion
6. Acknowledgements
7. References

1. ABSTRACT

The development of head and neck squamous cell carcinomas (HNSCCs) is a multistep process progressing from precancerous lesions to highly malignant tumors. A critical role in HNSCCs development and progression is played by EGFR family members including EGFR and ErbB2. The aim of this study was to investigate the effect of apigenin, a low molecular weight flavonoid contained in fruits and vegetables, on growth and survival and on EGFR/ErbB2 signaling in cell lines derived from HNSCCs of the tongue (CAL-27, SCC-15) or pharynx (FaDu). Using sulforhodamine B assay, FACS analysis and activated caspase-3 detection by immunofluorescence, we here demonstrate that apigenin dose-dependently inhibits survival and induces apoptosis of HNSCC cells. Further, by performing western blotting with antibodies specific for phosphorylated EGFR, ErbB2, Erk1/2 and Akt we demonstrate that apigenin reduces ligand-induced phosphorylation of EGFR and ErbB2 and impairs their downstream signaling. On the whole, our results suggest that apigenin properties might be exploited for chemoprevention and/or therapy of head and neck carcinomas.