Endogenously produced ganglioside GM3 endows etoposide and doxorubicin resistance by up-regulating Bcl-2 expression in 3LL Lewis lung carcinoma cells.
The ganglioside patterns have been shown to dramatically change during cell proliferation and differentiation and in certain cell-cycle phases, brain development, and cancer malignancy. To investigate the significance of the ganglioside GM3 in cancer malignancy, we established GM3-reconstituted cells by transfecting the cDNA of GM3 synthase into a GM3-deficient subclone of the 3LL Lewis lung carcinoma cell line (Uemura, S. (2003) Glycobiology, 13, 207-216). The GM3-reconstituted cells were resistant to apoptosis induced by etoposide and doxorubicin. There were no changes in the expression levels of topoisomerase IIalpha or P-glycoprotein, or in the uptake of doxorubicin between the GM3-reconstituted cells and the mock-transfected cells. To understand the mechanism of the etoposide-resistant phenotype acquired in the GM3-reconstituted cells, we investigated their apoptotic signaling. Although no difference was observed in the phosphorylation of p53 at serine-15-residue site by etoposide between the GM3-reconstituted cells and mock-transfected cells, the activation of both caspase-3 and caspase-9 was specifically inhibited in the former. We found that the anti-apoptotic protein B-cell leukemia/lymphoma 2 (Bcl-2) was increased in the GM3-reconstituted cells. Moreover, wild-type 3LL Lewis lung carcinoma cells, which have an abundance of GM3, exhibited no DNA fragmentation following etoposide treatment and expressed higher levels of the Bcl-2 protein compared with the J5 subclone. Thus, these results support the conclusion that endogenously produced GM3 is involved in malignant phenotypes, including anticancer drug resistance through up-regulating the Bcl-2 protein in this lung cancer cell line.
Department of Biomembrane and Biofunctional Chemistry, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan.
Mariko
M
Noguchi
Kazuya
K
Kabayama
Satoshi
S
Uemura
Byoung-won
BW
Kang
Masaki
M
Saito
Yasuyuki
Y
Igarashi
Jin-ichi
J
Inokuchi
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis; D018827:Carcinoma, Lewis Lung / Q000378:metabolism*; D053148:Caspase 3; D053453:Caspase 9; D061945:Caspase Inhibitors; D002518:Ceramides / Q000378:metabolism; D004317:Doxorubicin / Q000494:pharmacology*; D019008:Drug Resistance, Neoplasm; D005047:Etoposide / Q000494:pharmacology*; D005679:G(M3) Ganglioside / Q000378:metabolism*; D051379:Mice; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D018124:Receptors, Tumor Necrosis Factor / Q000502:physiology; D015854:Up-Regulation
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000970:Antineoplastic Agents; D061945:Caspase Inhibitors; D002518:Ceramides; D005679:G(M3) Ganglioside; D019253:Proto-Oncogene Proteins c-bcl-2; D018124:Receptors, Tumor Necrosis Factor; D005047:Etoposide; D004317:Doxorubicin; C505409:Casp3 protein, mouse; C506434:Casp9 protein, mouse; D053148:Caspase 3; D053453:Caspase 9