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Histone demethylase RBP2 decreases miR-21 in blast crisis of chronic myeloid leukemia.

Zhou M, Zeng J, Wang X, Wang X, Huang T, Fu Y, Sun T, Jia J, Chen C - Oncotarget (2015)

Bottom Line: In this study, we found that the histone H3 lysine 4 (H3K4) demethylase RBP2 (also called JARID1A and KDM5A) is underexpressed in CML-BP.This in turn activated PDCD4.In conclusion, RBP2 epigenetically downregulated miR-21 in blast transformation of CML.

View Article: PubMed Central - PubMed

Affiliation: Department of Hematology, Qilu Hospital of Shandong University, Jinan, Shandong, P. R. China.

ABSTRACT
Chronic myeloid leukemia in the blastic phase (CML-BP) responds poorly to clinical treatments and is usually fatal. In this study, we found that the histone H3 lysine 4 (H3K4) demethylase RBP2 (also called JARID1A and KDM5A) is underexpressed in CML-BP. The RBP2 histone demethylase stimulates leukemia cell differentiation and inhibits cell proliferation. We identified miR-21 was directly downregulated by RBP2 and found that miR-21 downregulated PDCD4 expression in leukemia cells. By binding to miR-21 promoter and by demethylating of trimethylated H3K4 at the miR-21 locus, RBP2 downregulated miR-21 expression. This in turn activated PDCD4. In conclusion, RBP2 epigenetically downregulated miR-21 in blast transformation of CML.

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PDCD4 is directly downregulated by miR-21qRT-PCR analysis of the level of (A) mature miR-21 and (B) PDCD4 after transfection with miR-21 mimics or inhibitor. Data are mean ± SEM of 3 independent experiments. (C) Western blot analysis of PDCD4 protein level with miR-21 mimics or inhibitor treatment. β-actin was a loading control. qRT-PCR analysis of the mRNA level of (D) RBP2 and (E) PDCD4 with RBP2 expression plasmid transfection without or with miR-21 mimics. Data are mean ± SEM of 3 independent experiments. (F) Western blot analysis of RBP2 and PDCD4 protein level with RBP2 expression plasmid transfection without or with miR-21 mimics. β-actin was a loading control. The results are from 3 independent experiments. *P< 0.05, **P< 0.01, ***P < 0.001.
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Figure 5: PDCD4 is directly downregulated by miR-21qRT-PCR analysis of the level of (A) mature miR-21 and (B) PDCD4 after transfection with miR-21 mimics or inhibitor. Data are mean ± SEM of 3 independent experiments. (C) Western blot analysis of PDCD4 protein level with miR-21 mimics or inhibitor treatment. β-actin was a loading control. qRT-PCR analysis of the mRNA level of (D) RBP2 and (E) PDCD4 with RBP2 expression plasmid transfection without or with miR-21 mimics. Data are mean ± SEM of 3 independent experiments. (F) Western blot analysis of RBP2 and PDCD4 protein level with RBP2 expression plasmid transfection without or with miR-21 mimics. β-actin was a loading control. The results are from 3 independent experiments. *P< 0.05, **P< 0.01, ***P < 0.001.

Mentions: Given that ectopic expression of RBP2 triggered inhibition of miR-21 expression in K562 and HL60 cells, we hypothesized a link between reduced miR-21 expression and defective clonogenesis of RBP2-expressed cells. We explored the effect of miR-21 on cell differentiation and proliferation. When K562 and HL60 cells were induced to undergo granulocytic differentiation by DMSO or ATRA (Supplemental Figure 1), the level of miR-21 was decreased (Figure 4A, B), which suggests that miR-21 blocks cell differentiation. In addition, miR-21 inhibitor significantly decreased the level of miR-21 in K562 and HL60 cells (Figure 5A), accompanied by reduced rate of cell proliferation (Figure 4C, D) and impaired colony-formation ability (Figure 4E, F), so miR-21 stimulates cell proliferation.


Histone demethylase RBP2 decreases miR-21 in blast crisis of chronic myeloid leukemia.

Zhou M, Zeng J, Wang X, Wang X, Huang T, Fu Y, Sun T, Jia J, Chen C - Oncotarget (2015)

PDCD4 is directly downregulated by miR-21qRT-PCR analysis of the level of (A) mature miR-21 and (B) PDCD4 after transfection with miR-21 mimics or inhibitor. Data are mean ± SEM of 3 independent experiments. (C) Western blot analysis of PDCD4 protein level with miR-21 mimics or inhibitor treatment. β-actin was a loading control. qRT-PCR analysis of the mRNA level of (D) RBP2 and (E) PDCD4 with RBP2 expression plasmid transfection without or with miR-21 mimics. Data are mean ± SEM of 3 independent experiments. (F) Western blot analysis of RBP2 and PDCD4 protein level with RBP2 expression plasmid transfection without or with miR-21 mimics. β-actin was a loading control. The results are from 3 independent experiments. *P< 0.05, **P< 0.01, ***P < 0.001.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4359230&req=5

Figure 5: PDCD4 is directly downregulated by miR-21qRT-PCR analysis of the level of (A) mature miR-21 and (B) PDCD4 after transfection with miR-21 mimics or inhibitor. Data are mean ± SEM of 3 independent experiments. (C) Western blot analysis of PDCD4 protein level with miR-21 mimics or inhibitor treatment. β-actin was a loading control. qRT-PCR analysis of the mRNA level of (D) RBP2 and (E) PDCD4 with RBP2 expression plasmid transfection without or with miR-21 mimics. Data are mean ± SEM of 3 independent experiments. (F) Western blot analysis of RBP2 and PDCD4 protein level with RBP2 expression plasmid transfection without or with miR-21 mimics. β-actin was a loading control. The results are from 3 independent experiments. *P< 0.05, **P< 0.01, ***P < 0.001.
Mentions: Given that ectopic expression of RBP2 triggered inhibition of miR-21 expression in K562 and HL60 cells, we hypothesized a link between reduced miR-21 expression and defective clonogenesis of RBP2-expressed cells. We explored the effect of miR-21 on cell differentiation and proliferation. When K562 and HL60 cells were induced to undergo granulocytic differentiation by DMSO or ATRA (Supplemental Figure 1), the level of miR-21 was decreased (Figure 4A, B), which suggests that miR-21 blocks cell differentiation. In addition, miR-21 inhibitor significantly decreased the level of miR-21 in K562 and HL60 cells (Figure 5A), accompanied by reduced rate of cell proliferation (Figure 4C, D) and impaired colony-formation ability (Figure 4E, F), so miR-21 stimulates cell proliferation.

Bottom Line: In this study, we found that the histone H3 lysine 4 (H3K4) demethylase RBP2 (also called JARID1A and KDM5A) is underexpressed in CML-BP.This in turn activated PDCD4.In conclusion, RBP2 epigenetically downregulated miR-21 in blast transformation of CML.

View Article: PubMed Central - PubMed

Affiliation: Department of Hematology, Qilu Hospital of Shandong University, Jinan, Shandong, P. R. China.

ABSTRACT
Chronic myeloid leukemia in the blastic phase (CML-BP) responds poorly to clinical treatments and is usually fatal. In this study, we found that the histone H3 lysine 4 (H3K4) demethylase RBP2 (also called JARID1A and KDM5A) is underexpressed in CML-BP. The RBP2 histone demethylase stimulates leukemia cell differentiation and inhibits cell proliferation. We identified miR-21 was directly downregulated by RBP2 and found that miR-21 downregulated PDCD4 expression in leukemia cells. By binding to miR-21 promoter and by demethylating of trimethylated H3K4 at the miR-21 locus, RBP2 downregulated miR-21 expression. This in turn activated PDCD4. In conclusion, RBP2 epigenetically downregulated miR-21 in blast transformation of CML.

Show MeSH
Related in: MedlinePlus