Investigation of the leukaemic activity of MLL-fusions
in human haematopoietic cells.
Doctoral thesis, UCL (University College London).
The mixed lineage leukaemia (MLL) gene is frequently the target of chromosomal translocation in infant leukaemia. Translocation results in an in-frame chimeric fusion gene which is implicated in both ALL and AML, with particularly poor prognoses. It is widely accepted that MLL has a crucial role in regulating haematopoiesis. Our lab has previously developed a murine model for conditional expression of MLL-fusions to establish a list of transcriptional target genes using Affymetrix GeneChip analysis. In order to study the role of MLL-fusion target genes in human leukaemia cells, we generated four independent immortalised myeloid cell lines from human cord blood, using the MLL-AF9 fusion, by means of lentiviral transduction. The transduced cells proliferated exponentially in liquid culture and were found to cause leukaemia upon xenotransplantation into immunodeficient mice. One of the target genes up-regulated by the MLL-fusions, RUVBL2, encodes an ATPase belonging to AAA+ family that has multiple roles in telomerase and chromatin-remodelling complexes. In this study, we demonstrate that RUVBL2 is also up-regulated by MLL-AF9 in human immortalised myeloid cells. shRNA knock down of RUVBL2 expression in these cells, and in the human leukaemia cell line THP-1, results in decreased cell proliferation and clonogenic potential, accompanied by an increase in apoptosis and differentiation, as judged by CD15 expression. Furthermore, inhibition of RUVBL2 expression in THP-1 cells leads to a reduction in hTERT mRNA expression and telomerase activity. Together, these data demonstrate the requirement of RUVBL2 to mediate MLL-fusion induced telomerase activity in human cells, and suggest the possibility of targeting RUVBL2 as a potential therapeutic strategy for MLL-fusion associated leukaemia.
|Title:||Investigation of the leukaemic activity of MLL-fusions in human haematopoietic cells|
|Open access status:||An open access version is available from UCL Discovery|
|Additional information:||Third party copyright material has been removed from the e-thesis.|
|UCL classification:||UCL > School of Life and Medical Sciences > Faculty of Population Health Sciences > Institute of Child Health > Department of Cancer > ICH - Molecular Haematology and Cancer Biology|
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