Anti-MSI2 (aa 1-100) polyclonal antibody

Background: Musashi2(Msi2)-Numb pathway de-regulation is a molecular mechanism underlying the transition of chronic phase Ph + CML to deadly blast crisis, particularly in cases with a NUP98/HOXA9 fusion from a t(7;11) (p15;p15). This study provides new insights on the mechanisms cooperating in driving MSI2 over-expression and progression of Ph-positive CML. Results: Herein we describe a t(7;11)(p15;p15) originating a NUP98 fusion with HOXA13, at 7p15, in a 39 year-old man in blast crisis of Ph-positive CML. Both MSI2 and HOXA9 were evaluated by quantitative RT-PCR in our patient and in a series of haematological malignancies. Up-regulation of both genes emerged only in the presence of NUP98/HOXA13 gene fusion. However, over-expression of MSI2, but not HOXA9, was found in 2 cases of Ph + blast crisis with additional chromosome aberrations other than t(7;11). To determine the mechanisms underlying MSI2 over-expression in our patient we performed Chromatin Immunoprecipitation and found that NUP98/HOXA13 fusion protein deregulates MSI2 gene by binding its promoter. Conclusions: To the best of our knowledge, this is the first molecular characterization of NUP98/HOXA13 fusion in blast crisis of Ph + CML. Our findings suggest cooperative mechanisms of MSI2 over-expression driven by HOXA proteins and strongly supports MSI2 as a prognostic marker and a candidate in target treatment of CML.

The lymphoid enhancer factor 1/T cell factor (LEF/TCF) family of transcription factors are downstream effectors of the WNT signaling pathway, which drives colon tumorigenesis. LEF/TCFs have a DNA sequence-specific high-mobility group (HMG) box that binds Wnt response elements (WREs). The "E tail" isoforms of TCFs are alternatively spliced to include a second DNA binding domain called the C-clamp. We show that induction of a dominant negative C-clamp version of TCF1 (dnTCF1E) induces p21 expression and a stall in the growth of DLD1 colon cancer cells. Induction of a C-clamp mutant did not efficiently induce p21, nor did it stall cell growth. Microarray analysis revealed that induction of p21 by wild-type dnTCF1E (dnTCF1E(WT)) correlated with a decrease in expression of multiple p21 suppressors that act at multiple levels from transcription (SP5, YAP1, and RUNX1), RNA stability (MSI2), and protein stability (CUL4A). We show that the C-clamp is a sequence-specific DNA binding domain that can make contacts with 5'-RCCG-3' elements upstream or downstream of WREs. The C-clamp-RCCG interaction was critical for TCF1E-mediated transcriptional control of p21-connected target gene promoters. Our results indicate that a rapid-response WNT/p21 circuit is driven by C-clamp target gene selection.