The Wilms tumor gene (WT1) is mutated or deleted in patients with heredofamilial syndromes associated with the development of Wilms tumors, but is infrequently mutated in sporadic Wilms tumors. By comparing the microarray profiles of syndromic versus sporadic Wilms tumors and WT1-inducible Saos-2 osteosarcoma cells, we identified interferon-inducible protein 16 (IFI16), a transcriptional modulator, as a differentially expressed gene and a candidate WT1 target gene. WT1 induction in Saos-2 osteosarcoma cells led to strong induction of IFI16 expression and its promoter activity was responsive to the WT1 protein. Immunohistochemical analysis showed that IFI16 and WT1 colocalized in WT1-replete Wilms tumors, but not in normal human midgestation fetal kidneys, suggesting that the ability of WT1 to regulate IFI16 in tumors represented an aberrant pathologic relationship. In addition, endogenous IFI16 and WT1 interacted in vivo in two Wilms tumor cell lines. Furthermore, IFI16 augmented the transcriptional activity of WT1 on both synthetic and physiological promoters. Strikingly, short hairpin RNA (shRNA)-mediated knockdown of either IFI16 or WT1 led to decreased growth of Wilms tumor cells. These data suggest that IFI16 and WT1, in certain cellular context including sporadic Wilms tumors, may support cell survival.

Purpose: To understand the changes in gene expression in polycythemia vera (PV) progenitor cells and their relationship to JAK2V617F.Experimental Design: Messenger RNA isolated from CD34 + cells from nine PV patients and normal controls was profiled using Affymetrix arrays. Gene expression change mediated by JAK2V617F was determined by profiling CD34 + cells transduced with the kinase and by analysis of leukemia cell lines harboring JAK2V617F, treated with an inhibitor.Results: A PV expression signature was enriched for genes involved in hematopoietic development, inflammatory responses, and cell proliferation. By quantitative reverse transcription-PCR, 23 genes were consistently deregulated in all patient samples. Several of these genes such as WT1 and KLF4 were regulated by JAK2, whereas others such as NFIB and EVI1 seemed to be deregulated in PV by a JAK2-independent mechanism. Using cell line models and comparing gene expression profiles of cell lines and PV CD34 + PV specimens, we have identified panels of 14 JAK2-dependent genes and 12 JAK2-independent genes. These two 14-and 12-gene sets could separate not only PV from normal CD34 + specimens, but also other MPN such as essential thrombocytosis and primary myelofibrosis from their normal counterparts.Conclusions: A subset of the aberrant gene expression in PV progenitor cells can be attributed to the action of the mutant kinase, but there remain a significant number of genes characteristic of the disease but deregulated by as yet unknown mechanisms. Genes deregulated in PV as a result of the action of JAK2V617F or independent of the kinase may represent other targets for therapy.

<p>Supplementary Table S4.</p>

<p>Supplementary Figure S2.</p>

<p>Supplementary Table S6.</p>

<p>Supplementary Legends.</p>

<p>Supplementary Figure S1.</p>

<p>Supplementary Table S5.</p>