FDB1_GM-CSF_Receptor_Mutant_Factorial_Time_Course_Study

To understand better the mechanisms controlling the balance between proliferation and self-renewal or growth suppression and differentiation during myelopoiesis we have utilized a cell line model that is responsive to myelopoietic cytokines and suited to large-scale gene-profiling. In addition to characterising differential growth or differentiation responses induced by Interleukin-3 (IL-3) and Granulocyte Macrophage Colony Stimulating Factor (GM-CSF) respectively, we increased the power of this study by monitoring global gene expression changes in response to signalling from two activated mutant GM-CSF receptors which display differential signalling and leukaemogenic activity. A factorial time-course design generated a substantial and powerful dataset and linear modelling identified the expression changes associated with continued proliferation, differentiation or leukaemic signalling. We focussed on the changing transcription factor profile and defined a set of novel genes with potential to regulate myeloid growth and differentiation. We identified gene expression patterns associated specifically with the leukemic GM-CSF receptor mutant and have shown that these overlap with events associated with the FLT3 internal tandem duplications (ITD) frequently observed in AML. Such commonalities may be a key to leukaemic receptor signalling and could provide new targets for myeloid leukaemia therapies. Keywords: time course, factorial design, cell line comparison, cytokine receptor, linear modelling Factorial design. First Factor was cell type with levels FDB1+Il-3 (Parental), FDB1+GM-CSF, FDB1 expressing V449E receptor mutant, FDB1 expressing FI-Delta receptor mutant. Second factor is time with levels 0, 6, 12, 24, 48 and 72 hours. Time course performed for FDB1+GM-CSF, V449E and FI-Delta cell lines with 0h reference. Matched time comparisons performed between V449E and FDB1+Il3 (0h only), V449E and FI-Delta, FI-Delta and FDB1+GM-CSF. Note 0hours represents time of removal of IL-3 (so that FDB1 cells in IL-3 (Parental), 0h is equilvalently FDB1+GM-CSF at 0h).