[Frontiers in Bioscience 17, 498-508, January 1, 2012]

Resveratrol and diallyl disulfide enhance curcumin-induced sarcoma cell apoptosis

Laura Masuelli1, Laura Marzocchella2, Chiara Focaccetti3, Ilaria Tresoldi2, Camilla Palumbo2, Valerio Izzi2, Monica Benvenuto2, Massimo Fantini2, Florigio Lista4, Umberto Tarantino5, Andrea Modesti2, Fabio Galvano6, 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 Biology, STA, Rome, Italy, 4Army Medical and Veterinary Research Center, Rome, Italy, 5Department of Surgery, University of Rome, Tor Vergata, Rome, Italy, 6Department 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) assay
3.4. Ultrastructural analysis
3.5. FACS analysis
3.6. In situ detection of apoptosis
3.7. Preparation of cell lysates and Western Blotting
3.8. Statistical analysis
4. Results
4.1. Inhibition of malignant rhabdoid (SJ-RH4, RD/18) and osteosarcoma (Saos-2) cell survival by DADS, RES and CUR alone or in combination
4.2. Morphological features of SJ-RH4 cells after treatment with DADS, RES and CUR alone or in combination
4.3. RES and DADS potentiate the apoptotic effect of CUR on SJ-RH4 and Saos-2 cell lines
4.4. Effect of DADS, RES and CUR alone or in combination on apoptosis and pro-survival signaling proteins
5. Discussion
6. Acknowledgements
7. References

1. ABSTRACT

Malignant tumors of mesenchimal origin such as rhabdomyosarcoma and osteosarcoma are highly aggressive pedriatic malignancies with a poor prognosis. Indeed, the initial response to chemotherapy is followed by chemoresistance. Diallyl disulfide (DADS), resveratrol (RES) and curcumin (CUR) are dietary chemopreventive phytochemicals which have been reported to have antineoplastic activity on rhabdomyosarcoma and osteosarcoma cells as single drugs. In this study we evaluated whether, as compared to the single compounds, the combination of DADS+RES, DADS+CUR and RES+CUR resulted in an enhancement of their antitumor potential on malignant rhabdoid (SJ-RH4, RD/18) or osteosarcoma (Saos-2) cell lines. Through FACS analysis and activated caspase-3 labeling we demonstrate that CUR induces apoptosis of rabdomyosarcoma and osteosarcoma cells and that this effect is potentiated when CUR is combined with RES or DADS. Further, we explored the effects of the compounds, alone or in combination, on signal transduction pathways involved in apoptosis and growth of cancer cells and show that in rhabdomyosarcoma cells the apoptotic effect of CUR, either alone or in combination, is independent of p53 activity. Our findings suggest that CUR and CUR-based combinations may have relevance for the treatment of p53-deficient cancers, which are often unaffected by conventional chemotherapies or radiotherapy.