Thalidomide can promote erythropoiesis by induction of STAT5 and repression of external pathway of apoptosis resulting in increased expression of GATA-1 transcription factor.
BACKGROUND
Thalidomide was shown to stimulate erythropoiesis and increase hemoglobin level in multiple myeloma patients, but way of such activity remains unclear. The aim of the study was to investigate the mechanisms of thalidomide stimulating effect on erythroid differentiation.


METHODS
Hematopoietic stem cells were isolated from bone marrow aspirates taken from myeloma patients and cultured with or without thalidomide. Then the generation of erythroid cells and the expression of STAT5, GATA-1, GATA-2, selected caspases and Bcl-2 family proteins in erythroid cells were assessed using flow cytometry and real-time PCR.


RESULTS
The generation of erythroblasts was higher in thalidomide than in control cultures (63.9% vs. 55.8%, p < 0.001). The expression of caspase 3 (cytometry 947.3 vs. 1021.0, p = 0.025; PCR 12.9 vs. 16.3, p = 0.025) and caspase 8 (cytometry 1050.8 vs. 1168.5, p = 0.033; PCR 16.2 vs. 17.8, p = 0.004) was significantly lower in thalidomide than in control cultures. The expression of STAT5 (cytometry 331.5 vs. 276.1, p = 0.015; PCR 24.3 vs. 21.1, p = 0.003) and GATA-1 (cytometry 259.7 vs. 232.0, p = 0.027; PCR 18.9 vs. 16.5, p = 0.003) was higher in thalidomide than in control cultures.


CONCLUSIONS
Our results suggest that thalidomide enhances expression of STAT5 in response of erythroid cells to erythropoietin and as a result of caspase 3 suppression. Moreover it may exert inhibitory effect on an external pathway of caspases activation with consequent decreased degradation of GATA-1 transcription factor by downstream caspases.
Department of Hematooncology and Bone Marrow Transplantation, Medical University of Lublin, Lublin, Poland. Electronic address: norbertgrzasko@gmail.com.
Norbert
N
Grzasko
Department of Hematooncology and Bone Marrow Transplantation, Medical University of Lublin, Lublin, Poland.
Sylwia
S
Chocholska
Department of Hematooncology and Bone Marrow Transplantation, Medical University of Lublin, Lublin, Poland.
Aneta
A
Goracy
Department of Hematooncology and Bone Marrow Transplantation, Medical University of Lublin, Lublin, Poland.
Marek
M
Hus
Department of Clinical Transplantology, Medical University of Lublin, Lublin, Poland.
Anna
A
Dmoszynska
D000368:Aged; D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D020169:Caspases / Q000096:biosynthesis; D002478:Cells, Cultured; D004790:Enzyme Induction / Q000187:drug effects; D041905:Erythroid Cells / Q000378:metabolism; D004920:Erythropoiesis / Q000187:drug effects*; D005260:Female; D050982:GATA1 Transcription Factor / Q000096:biosynthesis*; D050989:GATA2 Transcription Factor / Q000096:biosynthesis; D006412:Hematopoietic Stem Cells / Q000187:drug effects / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis; D050799:STAT5 Transcription Factor / Q000096:biosynthesis*; D013792:Thalidomide / Q000494:pharmacology*; D014157:Transcription Factors / Q000096:biosynthesis; D015854:Up-Regulation / Q000187:drug effects*
D051017:Apoptosis Regulatory Proteins; D050982:GATA1 Transcription Factor; C494688:GATA1 protein, human; D050989:GATA2 Transcription Factor; D019253:Proto-Oncogene Proteins c-bcl-2; D050799:STAT5 Transcription Factor; D014157:Transcription Factors; D013792:Thalidomide; D020169:Caspases
Apoptosis; Erythropoiesis; Multiple myeloma; Thalidomide