Transcriptional and post-transcriptional regulation of IL-1 beta, IL-6 and TNF-alpha genes in chronic lymphocytic leukaemia.
The present study was designed to define the mechanisms of interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6) and tumour necrosis factor (TNF-alpha) gene regulation in chronic lymphocytic leukaemia of B cell origin (B-CLL). By nuclear run-on analysis, all B-CLL cases displayed high levels of nuclear transcription of the IL-6 and TNF-alpha genes, whereas IL-1 beta gene transcription was only barely detectable. Upon in vitro culture for 1 h, B-CLL cells from different patients were substantially heterogeneous in terms of expression of steady state mRNA levels of IL-1 beta, IL-6 and TNF-alpha even though the pattern of nuclear transcription of these cytokines was only marginally affected by in vitro culture. mRNA stability was then examined and cytokine gene transcripts showed a half life of more than 2 h in cultured B-CLL cells and treatment with cycloheximide (CHX) did not affect cytokine transcript levels in B-CLL cells. These results indicate that: steady state levels of each mRNA do not reflect the rate of nuclear transcription of these cytokines in fresh or cultured B-CLL cells, that purification and in vitro culture of leukaemic cells may amplify cytokine gene expression in B-CLL, and that cytokine gene transcripts are relatively stable in B-CLL.
Rambaldi
A
A
Divisione di Ematologia Ospedali Riuniti, Bergamo, Italy.
Bettoni
S
S
Rossi
V
V
Tini
M L
ML
Giudici
G
G
Rizzo
V
V
Bassan
R
R
Mantovani
A
A
Barbui
T
T
Biondi
A
A
D015152:Blotting, Northern; D002478:Cells, Cultured; D015973:Gene Expression Regulation, Leukemic; D006801:Humans; D007375:Interleukin-1 / Q000235:genetics*; D015850:Interleukin-6 / Q000235:genetics*; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000235:genetics*; D012323:RNA Processing, Post-Transcriptional; D012333:RNA, Messenger / Q000378:metabolism; D014158:Transcription, Genetic; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics*
D007375:Interleukin-1; D015850:Interleukin-6; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha