Lack of ceramide generation and altered sphingolipid composition are associated with drug resistance in human ovarian carcinoma cells.
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.
Prinetti
Alessandro
A
Centre of Excellence for Neurodegenerative Disease, Department of Medical Chemistry, Biochemistry and Biotechnology, University of Milan, 20090 Segrate, Italy.
Millimaggi
Danilo
D
D'Ascenzo
Sandra
S
Clarkson
Matilda
M
Bettiga
Arianna
A
Chigorno
Vanna
V
Sonnino
Sandro
S
Pavan
Antonio
A
Dolo
Vincenza
V
D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D002417:Cattle; D045744:Cell Line, Tumor; D002518:Ceramides / Q000096:biosynthesis*; D019008:Drug Resistance, Neoplasm; D005260:Female; D005732:Gangliosides / Q000378:metabolism; D006801:Humans; D010051:Ovarian Neoplasms / Q000378:metabolism* / Q000473:pathology*; D017239:Paclitaxel / Q000494:pharmacology; D051381:Rats; D013107:Sphingolipids / Q000737:chemistry* / Q000378:metabolism*; D013108:Sphingomyelin Phosphodiesterase / Q000037:antagonists & inhibitors; D014316:Tritium
D000972:Antineoplastic Agents, Phytogenic; D002518:Ceramides; D005732:Gangliosides; D013107:Sphingolipids; D014316:Tritium; D013108:Sphingomyelin Phosphodiesterase; D017239:Paclitaxel