Katia Cortese1, Antonio Daga2, Massimiliano Monticone2, Sara Tavella3, Alessia Stefanelli2, Cinzia Aiello2, Angela Bisio4, Grazia Bellese1, Patrizio Castagnola5. 1. DIMES, Dipartimento di Medicina Sperimentale, Anatomia Umana, Università di Genova, Via de Toni 14, 16132 Genova, Italy. 2. IRCCS AOU - San Martino - IST, Largo Rosanna Benzi, 10, 16132 Genova, Italy. 3. DIMES, Dipartimento di Medicina Sperimentale, Anatomia Umana, Università di Genova, Via de Toni 14, 16132 Genova, Italy; IRCCS AOU - San Martino - IST, Largo Rosanna Benzi, 10, 16132 Genova, Italy. 4. Dip. Farmacia, Università di Genova, Via Brigata Salerno 13, 16147 Genova, Italy. 5. IRCCS AOU - San Martino - IST, Largo Rosanna Benzi, 10, 16132 Genova, Italy. Electronic address: patrizio.castagnola@hsanmartino.it.
Abstract
BACKGROUND: Carnosic acid (CA) is a diterpenoid found in Rosmarinus officinalis L. and Salvia officinalis L. as well as in many other Lamiaceae. This compound is reported to have antioxidant and antimicrobial properties. In addition, a number of reports showed that CA has a cytotoxic activity toward several cancer cell lines. PURPOSE: The aim of this study was to establish whether CA has any specific antiproliferative effect toward human glioblastoma (GBM) cells and to analyze the molecular mechanisms involved. METHODS: We evaluated cell survival by MTT assay, apoptosis and DNA content by flow cytometry, protein expression and phosphorylation by immunoblot analyses. RESULTS: Our results showed that CA inhibited cell survival on both normal astrocytes and GBM cells. In GBM cells, in particular, CA caused an early G2 block, a reduction in the percentage of cells expressing Ki67, an enhanced expression of p21(WAF) and induced apoptosis. Furthermore, we showed that CA promoted proteasomal degradation of several substrate proteins, including Cyclin B1, retinoblastoma (RB), SOX2, and glial fibrillary acid protein (GFAP), whereas MYC levels were not modified. In addition, CA dramatically reduced the activity of CDKs. CONCLUSION: In conclusion, our findings strongly suggest that CA promotes a profound deregulation of cell cycle control and reduces the survival of GBM cells via proteasome-mediated degradation of Cyclin B1, RB and SOX2.
BACKGROUND:Carnosic acid (CA) is a diterpenoid found in Rosmarinus officinalis L. and Salvia officinalis L. as well as in many other Lamiaceae. This compound is reported to have antioxidant and antimicrobial properties. In addition, a number of reports showed that CA has a cytotoxic activity toward several cancer cell lines. PURPOSE: The aim of this study was to establish whether CA has any specific antiproliferative effect toward humanglioblastoma (GBM) cells and to analyze the molecular mechanisms involved. METHODS: We evaluated cell survival by MTT assay, apoptosis and DNA content by flow cytometry, protein expression and phosphorylation by immunoblot analyses. RESULTS: Our results showed that CA inhibited cell survival on both normal astrocytes and GBM cells. In GBM cells, in particular, CA caused an early G2 block, a reduction in the percentage of cells expressing Ki67, an enhanced expression of p21(WAF) and induced apoptosis. Furthermore, we showed that CA promoted proteasomal degradation of several substrate proteins, including Cyclin B1, retinoblastoma (RB), SOX2, and glial fibrillary acid protein (GFAP), whereas MYC levels were not modified. In addition, CA dramatically reduced the activity of CDKs. CONCLUSION: In conclusion, our findings strongly suggest that CA promotes a profound deregulation of cell cycle control and reduces the survival of GBM cells via proteasome-mediated degradation of Cyclin B1, RB and SOX2.