RESUMO
Polycomb proteins form multiprotein complexes that repress target genes by chromatin remodeling. In this work, we report that the SUZ12 polycomb gene is over-expressed in bone marrow samples of patients at the blastic phase of chronic myeloid leukemia. We also found a direct interaction between polycomb group genes and the WNT signaling pathway in chronic myeloid leukemia transformation. Electrophoretic mobility shift assay (EMSA), Chromatin immunoprecipitation assay (ChIP), and mass spectrometry assays identified noncanonical WNT pathway members, such as WNT5A and WNT11, bound to the SUZ12 promoter. Immunohistochemistry and immunofluorescence with WNT5A and WNT11 antibodies confirmed nuclear localization. Knockdown of WNTs 1, 5A, and 11 with RNAi approaches showed that WNT members are capable of activating SUZ12 transcription with varying promoter affinities. Finally, we suggest that SUZ12 is blocking cellular differentiation, as SUZ12 knockdown release differentiation programs in chronic myeloid blastic phase (CML-BP) transformed cell line.
Assuntos
Proteínas de Transporte/genética , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Proteínas Nucleares/genética , Proteínas Wnt/fisiologia , Adulto , Células da Medula Óssea/patologia , Diferenciação Celular , Primers do DNA , Progressão da Doença , Feminino , Citometria de Fluxo , Humanos , Células K562 , Leucemia Mielogênica Crônica BCR-ABL Positiva/patologia , Masculino , Pessoa de Meia-Idade , Proteínas de Neoplasias , Complexo Repressor Polycomb 2 , Valores de Referência , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Transcrição , Regulação para Cima , beta Catenina/fisiologiaRESUMO
A 54-year-old woman was diagnosed with infiltrative ductal breast carcinoma. Two years after treatment, the patient developed an acute myeloid leukemia (AML) which harbored del(11q23) in 8% of the blast cells. The patient was submitted for allogeneic stem cell transplantation (aSCT) from her HLA-compatible sister. Ten months after transplantation, she relapsed with an AML with basophilic maturation characterized by CD45(low) CD33(high), CD117âº, CD13(-/+), HLA Dr(high), CD123(high), and CD203c⺠blast cells lacking expression of CD7, CD10, CD34, CD15, CD14, CD56, CD36, CD64, and cytoplasmic tryptase. Karyotype analysis showed the emergence of a new clone with t(2;14) and FISH analysis indicated the presence of MLL gene rearrangement consistent with del(11q23). Interestingly, AML blast cell DNA tested with microsatellite markers showed the same pattern as the donor's, suggesting that this AML emerged from donor cells. Additionally, polymorphisms of the XPA, XPD, XRCC1, XRCC3 and RAD51 DNA repair genes revealed three unfavorable alleles with low DNA repair capacity.In summary, we report the first case of AML involving XPD and XRCC3 polymorphisms from donor origin following allogeneic stem cell transplantation and highlight the potential need for careful analysis of DNA repair gene polymorphisms in selecting candidate donors prior to allogeneic stem cell transplantation.