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Myeloid cell differentiation arrest by miR-125b-1 in myelodysplastic syndrome and acute myeloid leukemia with the t(2;11)(p21;q23) translocation.

Bousquet M, Quelen C, Rosati R, Mansat-De Mas V, La Starza R, Bastard C, Lippert E, Talmant P, Lafage-Pochitaloff M, Leroux D, Gervais C, Viguié F, Lai JL, Terre C, Beverlo B, Sambani C, Hagemeijer A, Marynen P, Delsol G, Dastugue N, Mecucci C, Brousset P - J. Exp. Med. (2008)

Bottom Line: In addition to this, we have shown that this translocation is associated with a strong up-regulation of miR-125b (from 6- to 90-fold).In vitro experiments revealed that miR-125b was able to interfere with primary human CD34(+) cell differentiation, and also inhibited terminal (monocytic and granulocytic) differentiation in HL60 and NB4 leukemic cell lines.Therefore, miR-125b up-regulation may represent a new mechanism of myeloid cell transformation, and myeloid neoplasms carrying the t(2;11) translocation define a new clinicopathological entity.

View Article: PubMed Central - PubMed

Affiliation: Institut National de Santé et de Recherche Médicale, U563, Centre de Physiopathologie de Toulouse-Purpan, 31300 Toulouse, France.

ABSTRACT
Most chromosomal translocations in myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML) involve oncogenes that are either up-regulated or form part of new chimeric genes. The t(2;11)(p21;q23) translocation has been cloned in 19 cases of MDS and AML. In addition to this, we have shown that this translocation is associated with a strong up-regulation of miR-125b (from 6- to 90-fold). In vitro experiments revealed that miR-125b was able to interfere with primary human CD34(+) cell differentiation, and also inhibited terminal (monocytic and granulocytic) differentiation in HL60 and NB4 leukemic cell lines. Therefore, miR-125b up-regulation may represent a new mechanism of myeloid cell transformation, and myeloid neoplasms carrying the t(2;11) translocation define a new clinicopathological entity.

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Transient transfection with miR-125b blocks the differentiation of NB4 cells induced by RA. (A–D) Changes in morphology of May-Grunwald-Giemsa–stained cells (day 5): (A) NB4 cells electroporated with water (without RA), (B) NB4 cells electroporated with water (with RA), (C) NB4 cells electroporated with the microRNA negative control (with RA), and (D) NB4 cells electroporated with miR-125b (with RA). A representative experiment is shown. Bars, 5 μm. (E–H) Corresponding FACS experiments. A representative experiment is shown. (I) NBT staining. The data correspond to the mean from three independent experiments (P < 0.05).
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fig4: Transient transfection with miR-125b blocks the differentiation of NB4 cells induced by RA. (A–D) Changes in morphology of May-Grunwald-Giemsa–stained cells (day 5): (A) NB4 cells electroporated with water (without RA), (B) NB4 cells electroporated with water (with RA), (C) NB4 cells electroporated with the microRNA negative control (with RA), and (D) NB4 cells electroporated with miR-125b (with RA). A representative experiment is shown. Bars, 5 μm. (E–H) Corresponding FACS experiments. A representative experiment is shown. (I) NBT staining. The data correspond to the mean from three independent experiments (P < 0.05).

Mentions: The mechanisms accounting for miR-125b-1 up-regulation through the t(2;11)(p21;q23) translocation remain to be elucidated. However, such a high level of expression implies that miR-125b-1 could play a pivotal role in the pathogenesis of subsets of MDS and AML. Of note, in addition to the t(2;11) translocation, 10 cases also had a deletion of the 5q31 region. However, because there were some cases (n = 5) with isolated t(2;11), we suspected that this translocation was sufficient to interfere with the differentiation of myeloid cells. To address this question, we tested whether, in transfection experiments, miR-125b was able to block the differentiation of HL60 and NB4 leukemic cells upon chemical treatment. The experimental conditions allowed us to get a predominant maturation of HL60 into monocytic cells (after DMSO treatment), whereas NB4 cells treated with retinoic acid (RA) underwent characteristic granulocytic differentiation. We observed that in HL60 and NB4 cell lines, miR-125b was neither spontaneously up-regulated nor modulated during differentiation (unpublished data). After transient transfections, miR-125b significantly prevented the differentiation toward both lineages (Figs. 3 and 4). Regarding monocytic differentiation, the arrest of maturation was shown by both morphology (Fig. 3, A–D) and reduced expression of CD14 in HL60 cells (Fig. 3, E–H). These results were corroborated by those of the nonspecific esterase (NSE) staining (Fig. 3 I). Of note, it seemed that the blockage occurred between the expression of CD11b and CD14, i.e., in late stages of monocytic differentiation. As far as the granulocytic differentiation was concerned, the acquisition of CD11b was clearly affected by miR-125b transfection in NB4 cells upon RA treatment (Fig. 4, E–H). The maturation blockage was confirmed by morphological analysis (Fig. 4, A–D) and nitroblue tetrazolium (NBT) staining (Fig. 4 I).


Myeloid cell differentiation arrest by miR-125b-1 in myelodysplastic syndrome and acute myeloid leukemia with the t(2;11)(p21;q23) translocation.

Bousquet M, Quelen C, Rosati R, Mansat-De Mas V, La Starza R, Bastard C, Lippert E, Talmant P, Lafage-Pochitaloff M, Leroux D, Gervais C, Viguié F, Lai JL, Terre C, Beverlo B, Sambani C, Hagemeijer A, Marynen P, Delsol G, Dastugue N, Mecucci C, Brousset P - J. Exp. Med. (2008)

Transient transfection with miR-125b blocks the differentiation of NB4 cells induced by RA. (A–D) Changes in morphology of May-Grunwald-Giemsa–stained cells (day 5): (A) NB4 cells electroporated with water (without RA), (B) NB4 cells electroporated with water (with RA), (C) NB4 cells electroporated with the microRNA negative control (with RA), and (D) NB4 cells electroporated with miR-125b (with RA). A representative experiment is shown. Bars, 5 μm. (E–H) Corresponding FACS experiments. A representative experiment is shown. (I) NBT staining. The data correspond to the mean from three independent experiments (P < 0.05).
© Copyright Policy
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2571925&req=5

fig4: Transient transfection with miR-125b blocks the differentiation of NB4 cells induced by RA. (A–D) Changes in morphology of May-Grunwald-Giemsa–stained cells (day 5): (A) NB4 cells electroporated with water (without RA), (B) NB4 cells electroporated with water (with RA), (C) NB4 cells electroporated with the microRNA negative control (with RA), and (D) NB4 cells electroporated with miR-125b (with RA). A representative experiment is shown. Bars, 5 μm. (E–H) Corresponding FACS experiments. A representative experiment is shown. (I) NBT staining. The data correspond to the mean from three independent experiments (P < 0.05).
Mentions: The mechanisms accounting for miR-125b-1 up-regulation through the t(2;11)(p21;q23) translocation remain to be elucidated. However, such a high level of expression implies that miR-125b-1 could play a pivotal role in the pathogenesis of subsets of MDS and AML. Of note, in addition to the t(2;11) translocation, 10 cases also had a deletion of the 5q31 region. However, because there were some cases (n = 5) with isolated t(2;11), we suspected that this translocation was sufficient to interfere with the differentiation of myeloid cells. To address this question, we tested whether, in transfection experiments, miR-125b was able to block the differentiation of HL60 and NB4 leukemic cells upon chemical treatment. The experimental conditions allowed us to get a predominant maturation of HL60 into monocytic cells (after DMSO treatment), whereas NB4 cells treated with retinoic acid (RA) underwent characteristic granulocytic differentiation. We observed that in HL60 and NB4 cell lines, miR-125b was neither spontaneously up-regulated nor modulated during differentiation (unpublished data). After transient transfections, miR-125b significantly prevented the differentiation toward both lineages (Figs. 3 and 4). Regarding monocytic differentiation, the arrest of maturation was shown by both morphology (Fig. 3, A–D) and reduced expression of CD14 in HL60 cells (Fig. 3, E–H). These results were corroborated by those of the nonspecific esterase (NSE) staining (Fig. 3 I). Of note, it seemed that the blockage occurred between the expression of CD11b and CD14, i.e., in late stages of monocytic differentiation. As far as the granulocytic differentiation was concerned, the acquisition of CD11b was clearly affected by miR-125b transfection in NB4 cells upon RA treatment (Fig. 4, E–H). The maturation blockage was confirmed by morphological analysis (Fig. 4, A–D) and nitroblue tetrazolium (NBT) staining (Fig. 4 I).

Bottom Line: In addition to this, we have shown that this translocation is associated with a strong up-regulation of miR-125b (from 6- to 90-fold).In vitro experiments revealed that miR-125b was able to interfere with primary human CD34(+) cell differentiation, and also inhibited terminal (monocytic and granulocytic) differentiation in HL60 and NB4 leukemic cell lines.Therefore, miR-125b up-regulation may represent a new mechanism of myeloid cell transformation, and myeloid neoplasms carrying the t(2;11) translocation define a new clinicopathological entity.

View Article: PubMed Central - PubMed

Affiliation: Institut National de Santé et de Recherche Médicale, U563, Centre de Physiopathologie de Toulouse-Purpan, 31300 Toulouse, France.

ABSTRACT
Most chromosomal translocations in myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML) involve oncogenes that are either up-regulated or form part of new chimeric genes. The t(2;11)(p21;q23) translocation has been cloned in 19 cases of MDS and AML. In addition to this, we have shown that this translocation is associated with a strong up-regulation of miR-125b (from 6- to 90-fold). In vitro experiments revealed that miR-125b was able to interfere with primary human CD34(+) cell differentiation, and also inhibited terminal (monocytic and granulocytic) differentiation in HL60 and NB4 leukemic cell lines. Therefore, miR-125b up-regulation may represent a new mechanism of myeloid cell transformation, and myeloid neoplasms carrying the t(2;11) translocation define a new clinicopathological entity.

Show MeSH
Related in: MedlinePlus