Signal transduction pathways in Burkitt's lymphoma cell lines BL41 and DG75 with different sensitivity to doxorubicin.
OBJECTIVE
To understand the biochemical basis of cell sensitivity to cytotoxic effect of doxorubicine (DOX), we investigated signaling cascades mediated by c-Jun N-terminal protein kinases (JNK1/2), p38 mitogen-activated protein kinases (MAPK), extracellular signal-regulated protein kinase (ERK1/2) and protein kinase B/Akt in both DOX-sensitive BL41 and the DOX-resistant DG75 Burkitt's lymphoma (BL) cell lines.


METHODS
To test the effect of DOX on different signaling cascades, BL41 and DG75 cells were treated with DOX for varying lengths of time. Cytotoxic effect of DOX was analyzed by Hoechst 33342 staining. Total amount of JNK1/2, ERK1/2, p38 MARK, Akt proteins, and also phosphorylated/activated forms of these enzymes were detected using Western blot analysis with specific antibodies. Immunophenotypic analysis of BL41 and DG75 cells was performed by indirect immunofluorescence staining.


RESULTS
Our findings demonstrated that DOX treatment of the BL41 cells led to sustained activation of JNK1/2 and p38 MAPK. This activation/phosphorylation did not result from increased expression of either JNK1/2 or p38 MAPK since protein levels of JNK1/2 and p38 MAPK in DOX-treated and untreated cells were unaltered. Apoptotic signaling cascade induced by DOX in BL41 cell was accompanied by Akt dephosphorylation. The effect of DOX in drug-resistant cell line DG75 convoyed by dephosphorylation of JNK1/2, p38 MAPK and activation of Akt. Fate of BL cells did not depend from ERK activity.


CONCLUSIONS
The outcome of cellular response to DOX in BL cell lines is determined by interference of at least three signaling pathways: JNK1/2, p38 MAPK and PKB/Akt. The balance between Akt/PKB and MAPK pathways is important in determining whether BL cells survive or undergo apoptosis in response to DOX treatment.
Shlapatska
Larysa M
LM
R.E. Kavetsky Institute of Experimental Pathology, Oncology and Radiobiology NAS of Ukraine, Kyiv, Ukraine. larisash@onconet.kiev.ua.
Berdova
Ganna G
GG
Kovalevska
Larysa M
LM
Kulyk
Galyna I
GI
Klein
George
G
Sidorenko
Svitlana P
SP
Chekhun
Vasyl F
VF
D000903:Antibiotics, Antineoplastic / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D002051:Burkitt Lymphoma / Q000378:metabolism / Q000473:pathology*; D045744:Cell Line, Tumor / Q000737:chemistry / Q000187:drug effects; D004317:Doxorubicin / Q000494:pharmacology*; D019008:Drug Resistance, Neoplasm; D006801:Humans; D016130:Immunophenotyping; D020935:MAP Kinase Signaling System; D019950:Mitogen-Activated Protein Kinase 1 / Q000032:analysis; D048052:Mitogen-Activated Protein Kinase 3 / Q000032:analysis; D048055:Mitogen-Activated Protein Kinase 8 / Q000032:analysis; D048056:Mitogen-Activated Protein Kinase 9 / Q000032:analysis; D009363:Neoplasm Proteins / Q000032:analysis; D010766:Phosphorylation / Q000187:drug effects; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000032:analysis / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000032:analysis / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D015398:Signal Transduction / Q000187:drug effects; D048051:p38 Mitogen-Activated Protein Kinases / Q000032:analysis
D000903:Antibiotics, Antineoplastic; D009363:Neoplasm Proteins; D011518:Proto-Oncogene Proteins; D004317:Doxorubicin; D048056:Mitogen-Activated Protein Kinase 9; C494918:AKT1 protein, human; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D048055:Mitogen-Activated Protein Kinase 8; D048051:p38 Mitogen-Activated Protein Kinases