Biochem. J. (2006) 395
(311–318) (Printed in Great Britain)
Lack of ceramide generation and altered sphingolipid composition are associated with drug resistance in human ovarian carcinoma cells
Alessandro PRINETTI*1, Danilo MILLIMAGGI†1, Sandra D'ASCENZO†, Matilda CLARKSON†, Arianna BETTIGA*, Vanna CHIGORNO*, Sandro SONNINO*, Antonio PAVAN† and Vincenza DOLO†2
*Centre of Excellence for Neurodegenerative Disease, Department of Medical Chemistry, Biochemistry and Biotechnology, University of Milan, 20090 Segrate, Italy, and †Department of Experimental Medicine, University of L'Aquila, 67100 L'Aquila, Italy
PTX (Paclitaxel®) is an antimitotic agent used in the treatment of a number of major solid tumours, particularly in breast and ovarian cancer. This study was undertaken to gain insight into the molecular alterations producing PTX resistance in ovarian cancer. PTX treatment is able to induce apoptosis in the human ovarian carcinoma cell line, CABA I. PTX-induced apoptosis in CABA I cells was accompanied by an increase in the cellular Cer (ceramide) levels and a decrease in the sphingomyelin levels, due to the activation of sphingomyelinases. The inhibition of acid sphingomyelinase decreased PTX-induced apoptosis. Under the same experimental conditions, PTX had no effect on Cer and sphingomyelin levels in the stable PTX-resistant ovarian carcinoma cell line, CABA-PTX.
The acquisition of the PTX-resistant phenotype is accompanied by unique alterations in the complex sphingolipid pattern found on lipid extraction. In the drug-resistant cell line, the levels of sphingomyelin and neutral glycosphingolipids were unchanged compared with the drug-sensitive cell line. The ganglioside pattern in CABA I cells is more complex compared with that of CABA-PTX cells. Specifically, we found that the total ganglioside content in CABA-PTX cells was approximately half of that in CABA I cells, and GM3 ganglioside content was remarkably higher in the drug-resistant cell line.
Taken together our findings indicate that: i) Cer generated by acid sphingomyelinase is involved in PTX-induced apoptosis in ovarian carcinoma cells, and PTX-resistant cells are characterized by their lack of increased Cer upon drug treatment, ii) PTX resistance might be correlated with an alteration in metabolic Cer patterns specifically affecting cellular ganglioside composition.
Key words: ceramide, drug resistance, ganglioside, ovarian cancer, PTX (Paclitaxel®), sphingolipids.
Abbreviations used: Cer, ceramide; C6-Cer, N-hexanoyl-sphingosine; C16-Cer, N-palmitoyl-sphingosine; FB1, fumonisin B1; FCS, foetal calf serum; GCS, GlcCer-synthase; GD3S, GD3-synthase; GM3S, GM3-synthase; IMP, imipramine hydrochloride; ManA, manumycin A; MDR, multidrug resistance; MRP, MDR-associated protein; P-gp, P-glycoprotein; PTX, Paclitaxel®; SM, sphingomyelin; SMase, sphingomyelinase; XTT/PMS, tetrazolium/phenazine methosulphate.
1These authors contributed equally to this work.
2To whom correspondence should be addressed (email Dolo@univaq.it).
Ganglioside and glycosphingolipid nomenclature is in accordance with Svennerholm [37] and the IUPAC-IUBMB recommendations [38,39].
Received 21 July 2005/2 December 2005; accepted 16 December 2005
Published as BJ Immediate Publication 16 December 2005, doi:10.1042/BJ20051184
The Biochemical Society, London ©2006
Editorial Advisory Panel
RSS feeds
Table of contents by email
My BJ toolbox
