IJUP08 - Universidade do Porto

Effects of etoposide, doxorubicin and cytarabine in Burkitt
Lymphoma cell lines
R. Lima 1,2 , H. Seca 1 , M. I. Castro 1,2 , S. Brás 1 , P.Soares 1,3 , M.S. Nascimento 2,4 , M. H.
Vasconcelos 1,2
1 Cancer Biology Group, IPATIMUP- Institute of Molecular Pathology and Immunology of the
University of Porto, University of Porto, Portugal.
2 Department of Microbiology, Faculty of Pharmacy, University of Porto, Portugal.
3 Faculty of Medicine, University of Porto, Portugal.
4 Research Center of Organic Chemistry, Phytochemistry and Pharmacology of the University of
Porto (CEQOFFUP), University of Porto, Portugal.
Epstein-Barr Virus (EBV) infects more than 90% of the world population and it persists as
a lifelong infection mainly without symptoms. EBV is usually kept in latent form, possibly
leading to cellular transformation. In fact, EBV infection has already been associated with
the development of some neoplasias, namely Burkitt Lymphoma (BL). Traditionally,
treatment of this type of cancer is achieved using cytotoxic drugs.
The aim of this work was to verify the effect of some cytotoxic drugs such as etoposide,
doxorubicin and cytarabine in BL (EBV positive and EBV negative) cells in culture.
To address this question two isogenic BL cell lines were used: the AKATA EBV negative
cell line and its parental AKATA EBV positive cell line [1,2]. Both cell lines were treated
over 48h with etoposide, doxorubicin and cytarabine. Cellular viability was analysed with
the Trypan Blue exclusion assay. Apoptosis levels were assessed with the TUNEL assay
and the expression of apoptotic proteins was verified by Western Blot.
The EBV positive cells were more sensitive to etoposide and doxorubicin than the EBV
negative cells, but their response to cytarabine was similar. Basal programmed cell death
levels were higher in the EBV positive than in the EBV negative cells. In agreement with
this, EBV positive cells had higher levels of cleaved PARP than the EBV negative cells.
Both cell lines had an increase in programmed cell death following treatments with all
drugs. In the EBV positive cells, Bcl-2 expression was lower than in the EBV negative
cells and decreased with all treatments.
We concluded that EBV positive cells had higher basal programmed cell death levels than
the EBV negative cells and that they were more sensitive to doxorubicin and etoposide.
However, they presented similar response to cytarabine. We are currently investigating if
EBV is responsible for the differences observed in the response of the two cell lines.
References:
[1] Takada and Ono (1989), J Virol 63,445-449.
[2] Shimizu et al. (1994), J Virol 68,6069-6073.
Acknowledgments:
The authors would like to thank Professor Kenzo Takada for the AKATA cell lines (EBV negative
and EBV positive). They would also like to acknowledge Liliana Santos for technical assistance
and the Universidade do Porto and Caixa Geral de Depósitos for financial support. R. Lima is
recipient of a PhD grant (SFRH/BD/21759/2005) from FCT.
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