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Epstein-Barr virus-mediated protection against etoposide-induced apoptosis in BJA-B B cell lymphoma cells: role of Bcl-2 and caspase proteins.
Arch Virol 2004; 149(2):289-302AV

Abstract

Epstein-Barr virus (EBV)-infected B cell lymphomas are resistant to apoptosis during cancer development and treatment with therapies. The molecular controls that determine why EBV infection causes apoptosis resistance need further definition. EBV-positive and EBV-negative BJA-B B cell lymphoma cell lines were used to compare the expression of selected apoptosis-regulating Bcl-2 and caspase proteins in EBV-related apoptosis resistance, after 8 hr or 18-24 hr etoposide treatment (80 microM). Apoptosis was quantified using morphology and verified with Hoechst 33258 nuclear stain and electron microscopy. Fluorescence activated cell sorting (FACS) was used to analyse effects on cell cycle of the EBV infection as well as etoposide treatment. Anti-apoptotic Bcl-2 and Bcl-XL, pro-apoptotic Bax, caspase-3 and caspase-9 expression and activation were analysed using Western immunoblots and densitometry. EBV-positive cultures had significantly lower levels of apoptosis in untreated and etoposide-treated cultures in comparison with EBV-negative cultures (p < 0.05). FACS analysis indicated a strong G2/M block in both cell sublines after etoposide treatment. Endogenous Bcl-2 was minimal in the EBV-negative cells in comparison with strong expression in EBV-positive cells. These levels did not alter with etoposide treatment. Bcl-XL was expressed endogenously in both cell lines and had reduced expression in EBV-negative cells after etoposide treatment. Bax showed no etoposide-induced alterations in expression. Pro-caspase-9 and -3 were seen in both EBV-positive and -negative cells. Etoposide induced cleavage of caspase-9 in both cell lines, with the EBV-positive cells having proportionally less cleavage product, in agreement with their lower levels of apoptosis. Caspase-3 cleavage occurred in the EBV-negative etoposide-treated cells but not in the EBV-positive cells. The results indicate that apoptosis resistance in EBV-infected B cell lymphomas is promoted by an inactive caspase-3 pathway and elevated expression of Bcl-2 that is not altered by etoposide drug treatment.

Authors+Show Affiliations

Dept of Molecular and Cellular Pathology, School of Medicine, University of Queensland, Brisbane, Australia.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

14745596

Citation

Blood, A, et al. "Epstein-Barr Virus-mediated Protection Against Etoposide-induced Apoptosis in BJA-B B Cell Lymphoma Cells: Role of Bcl-2 and Caspase Proteins." Archives of Virology, vol. 149, no. 2, 2004, pp. 289-302.
Blood A, Edwards CJ, Ishii HH, et al. Epstein-Barr virus-mediated protection against etoposide-induced apoptosis in BJA-B B cell lymphoma cells: role of Bcl-2 and caspase proteins. Arch Virol. 2004;149(2):289-302.
Blood, A., Edwards, C. J., Ishii, H. H., Pat, B. K., Bryson, G., Sculley, T. B., & Gobe, G. C. (2004). Epstein-Barr virus-mediated protection against etoposide-induced apoptosis in BJA-B B cell lymphoma cells: role of Bcl-2 and caspase proteins. Archives of Virology, 149(2), pp. 289-302.
Blood A, et al. Epstein-Barr Virus-mediated Protection Against Etoposide-induced Apoptosis in BJA-B B Cell Lymphoma Cells: Role of Bcl-2 and Caspase Proteins. Arch Virol. 2004;149(2):289-302. PubMed PMID: 14745596.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Epstein-Barr virus-mediated protection against etoposide-induced apoptosis in BJA-B B cell lymphoma cells: role of Bcl-2 and caspase proteins. AU - Blood,A, AU - Edwards,C J, AU - Ishii,H H, AU - Pat,B K, AU - Bryson,G, AU - Sculley,T B, AU - Gobe,G C, Y1 - 2003/11/04/ PY - 2003/05/29/received PY - 2003/08/13/accepted PY - 2004/1/28/pubmed PY - 2004/3/18/medline PY - 2004/1/28/entrez SP - 289 EP - 302 JF - Archives of virology JO - Arch. Virol. VL - 149 IS - 2 N2 - Epstein-Barr virus (EBV)-infected B cell lymphomas are resistant to apoptosis during cancer development and treatment with therapies. The molecular controls that determine why EBV infection causes apoptosis resistance need further definition. EBV-positive and EBV-negative BJA-B B cell lymphoma cell lines were used to compare the expression of selected apoptosis-regulating Bcl-2 and caspase proteins in EBV-related apoptosis resistance, after 8 hr or 18-24 hr etoposide treatment (80 microM). Apoptosis was quantified using morphology and verified with Hoechst 33258 nuclear stain and electron microscopy. Fluorescence activated cell sorting (FACS) was used to analyse effects on cell cycle of the EBV infection as well as etoposide treatment. Anti-apoptotic Bcl-2 and Bcl-XL, pro-apoptotic Bax, caspase-3 and caspase-9 expression and activation were analysed using Western immunoblots and densitometry. EBV-positive cultures had significantly lower levels of apoptosis in untreated and etoposide-treated cultures in comparison with EBV-negative cultures (p < 0.05). FACS analysis indicated a strong G2/M block in both cell sublines after etoposide treatment. Endogenous Bcl-2 was minimal in the EBV-negative cells in comparison with strong expression in EBV-positive cells. These levels did not alter with etoposide treatment. Bcl-XL was expressed endogenously in both cell lines and had reduced expression in EBV-negative cells after etoposide treatment. Bax showed no etoposide-induced alterations in expression. Pro-caspase-9 and -3 were seen in both EBV-positive and -negative cells. Etoposide induced cleavage of caspase-9 in both cell lines, with the EBV-positive cells having proportionally less cleavage product, in agreement with their lower levels of apoptosis. Caspase-3 cleavage occurred in the EBV-negative etoposide-treated cells but not in the EBV-positive cells. The results indicate that apoptosis resistance in EBV-infected B cell lymphomas is promoted by an inactive caspase-3 pathway and elevated expression of Bcl-2 that is not altered by etoposide drug treatment. SN - 0304-8608 UR - https://www.unboundmedicine.com/medline/citation/14745596/Epstein_Barr_virus_mediated_protection_against_etoposide_induced_apoptosis_in_BJA_B_B_cell_lymphoma_cells:_role_of_Bcl_2_and_caspase_proteins_ L2 - https://dx.doi.org/10.1007/s00705-003-0212-8 DB - PRIME DP - Unbound Medicine ER -