BACKGROUND: We previously described a t(2;11)(p21;q23) chromosomal translocation found in patients with myelodysplasia or acute myeloid leukemia that leads to over-expression of the microRNA miR-125b, and we showed that transplantation of mice with murine stem/progenitor cells overexpressing miR-125b is able to induce leukemia. In this study, we investigated the mechanism of myeloid transformation by miR-125b. DESIGN AND METHODS: To investigate the consequences of miR-125b over-expression on myeloid differentiation, apoptosis and proliferation, we used the NB4 and HL60 human promyelocytic cell lines and the 32Dclone3 murine promyelocytic cell line. To test whether miR-125b is able to transform myeloid cells, we used the non-tumorigenic and interleukin-3-dependent 32Dclone3 cell line over-expressing miR-125b, in xenograft experiments in nude mice and in conditions of interleukin-3 deprivation. To identify new miR-125b targets, we compared, by RNA-sequencing, the transcriptome of cell lines that do or do not over-express miR-125b. RESULTS: We showed that miR-125b over-expression blocks apoptosis and myeloid differentiation and enhances proliferation in both species. More importantly, we demonstrated that miR-125b is able to transform the 32Dclone3 cell line by conferring growth independence from interleukin-3; xenograft experiments showed that these cells form tumors in nude mice. Using RNA-sequencing and quantitative real-time polymerase chain reaction experiments, we identified multiple miR-125b targets. We demonstrated that ABTB1, an anti-proliferative factor, is a new direct target of miR-125b and we confirmed that CBFB, a transcription factor involved in hematopoiesis, is also targeted by miR-125b. MiR-125b controls apoptosis by down-regulating genes involved in the p53 pathway including BAK1 and TP53INP1. CONCLUSIONS: This study demonstrates that in a myeloid context, miR-125b is an oncomiR able to transform cell lines. miR-125b blocks myeloid differentiation in part by targeting CBFB, blocks apoptosis through down-regulation of multiple genes involved in the p53 pathway, and confers a proliferative advantage to human and mouse myeloid cell lines in part by targeting ABTB1.
BACKGROUND: We previously described a t(2;11)(p21;q23) chromosomal translocation found in patients with myelodysplasia or acute myeloid leukemia that leads to over-expression of the microRNA miR-125b, and we showed that transplantation of mice with murine stem/progenitor cells overexpressing miR-125b is able to induce leukemia. In this study, we investigated the mechanism of myeloid transformation by miR-125b. DESIGN AND METHODS: To investigate the consequences of miR-125b over-expression on myeloid differentiation, apoptosis and proliferation, we used the NB4 and HL60 human promyelocytic cell lines and the 32Dclone3 murine promyelocytic cell line. To test whether miR-125b is able to transform myeloid cells, we used the non-tumorigenic and interleukin-3-dependent 32Dclone3 cell line over-expressing miR-125b, in xenograft experiments in nude mice and in conditions of interleukin-3 deprivation. To identify new miR-125b targets, we compared, by RNA-sequencing, the transcriptome of cell lines that do or do not over-express miR-125b. RESULTS: We showed that miR-125b over-expression blocks apoptosis and myeloid differentiation and enhances proliferation in both species. More importantly, we demonstrated that miR-125b is able to transform the 32Dclone3 cell line by conferring growth independence from interleukin-3; xenograft experiments showed that these cells form tumors in nude mice. Using RNA-sequencing and quantitative real-time polymerase chain reaction experiments, we identified multiple miR-125b targets. We demonstrated that ABTB1, an anti-proliferative factor, is a new direct target of miR-125b and we confirmed that CBFB, a transcription factor involved in hematopoiesis, is also targeted by miR-125b. MiR-125b controls apoptosis by down-regulating genes involved in the p53 pathway including BAK1 and TP53INP1. CONCLUSIONS: This study demonstrates that in a myeloid context, miR-125b is an oncomiR able to transform cell lines. miR-125b blocks myeloid differentiation in part by targeting CBFB, blocks apoptosis through down-regulation of multiple genes involved in the p53 pathway, and confers a proliferative advantage to human and mouse myeloid cell lines in part by targeting ABTB1.
Authors: Shangqin Guo; Jun Lu; Rita Schlanger; Hao Zhang; Judy Y Wang; Michelle C Fox; Louise E Purton; Heather H Fleming; Bradley Cobb; Matthias Merkenschlager; Todd R Golub; David T Scadden Journal: Proc Natl Acad Sci U S A Date: 2010-07-08 Impact factor: 11.205
Authors: Y Enomoto; J Kitaura; K Hatakeyama; J Watanuki; T Akasaka; N Kato; M Shimanuki; K Nishimura; M Takahashi; M Taniwaki; C Haferlach; R Siebert; M J S Dyer; N Asou; H Aburatani; H Nakakuma; T Kitamura; T Sonoki Journal: Leukemia Date: 2011-07-08 Impact factor: 11.528
Authors: R Visone; P Pallante; A Vecchione; R Cirombella; M Ferracin; A Ferraro; S Volinia; S Coluzzi; V Leone; E Borbone; C-G Liu; F Petrocca; G Troncone; G A Calin; A Scarpa; C Colato; G Tallini; M Santoro; C M Croce; A Fusco Journal: Oncogene Date: 2007-06-11 Impact factor: 9.867
Authors: M Valtieri; D J Tweardy; D Caracciolo; K Johnson; F Mavilio; S Altmann; D Santoli; G Rovera Journal: J Immunol Date: 1987-06-01 Impact factor: 5.422
Authors: N Gefen; V Binder; M Zaliova; Y Linka; M Morrow; A Novosel; L Edry; L Hertzberg; N Shomron; O Williams; J Trka; A Borkhardt; S Izraeli Journal: Leukemia Date: 2009-11-05 Impact factor: 11.528
Authors: Burcu Gurer Giray; Gurol Emekdas; Seda Tezcan; Mahmut Ulger; Mehmet Sami Serin; Orhan Sezgin; Engin Altintas; Eyup Naci Tiftik Journal: Mol Biol Rep Date: 2014-03-05 Impact factor: 2.316
Authors: U Knackmuss; S E Lindner; T Aneichyk; B Kotkamp; Z Knust; A Villunger; S Herzog Journal: Cell Death Differ Date: 2015-07-03 Impact factor: 15.828