Limits...
Inhibition of euchromatic histone methyltransferase 1 and 2 sensitizes chronic myeloid leukemia cells to interferon treatment.

Loh SW, Ng WL, Yeo KS, Lim YY, Ea CK - PLoS ONE (2014)

Bottom Line: Chromatin immunoprecipitation assay shows that BIX01294 treatment enhances type I interferon response by reducing H3K9me2 at the promoters of interferon-stimulated genes.Moreover, our data suggest that the expression level of EHMT1 and EHMT2 inversely correlates with the type I interferon responsiveness in CML cell lines.Our study sheds light on the role of EHMT1 and EHMT2 as potential targets in improving the efficacy of standard treatments of CML.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia.

ABSTRACT

Background: H3K9 methylation is one of the essential histone post-translational modifications for heterochromatin formation and transcriptional repression. Recently, several studies have demonstrated that H3K9 methylation negatively regulates the type I interferon response.

Results: We report the application of EHMT1 and EHMT2 specific chemical inhibitors to sensitize CML cell lines to interferon and imatinib treatments. Inhibition of EHMT1 and EHMT2 with BIX01294 enhances the cytotoxicity of IFN╬▒2a in four CML cell lines, K562, KCL22, BV173 and KT1 cells. Chromatin immunoprecipitation assay shows that BIX01294 treatment enhances type I interferon response by reducing H3K9me2 at the promoters of interferon-stimulated genes. Additionally, BIX01294 treatment augments IFN╬▒2a- and imatinib-mediated apoptosis in CML cell lines. Moreover, our data suggest that the expression level of EHMT1 and EHMT2 inversely correlates with the type I interferon responsiveness in CML cell lines.

Conclusions: Our study sheds light on the role of EHMT1 and EHMT2 as potential targets in improving the efficacy of standard treatments of CML.

Show MeSH

Related in: MedlinePlus

BIX01294 inhibits the proliferation of CML cells.K562 (A), KCL22 (B), BV173 (C) and KT1 (D) cells were cultured with various concentrations of BIX01294 and IFN╬▒2a as indicated. After four days, cell proliferation was measured with a MTT assay. Results represent the mean ┬▒ SD in quadruplicate experiments.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4117596&req=5

pone-0103915-g002: BIX01294 inhibits the proliferation of CML cells.K562 (A), KCL22 (B), BV173 (C) and KT1 (D) cells were cultured with various concentrations of BIX01294 and IFN╬▒2a as indicated. After four days, cell proliferation was measured with a MTT assay. Results represent the mean ┬▒ SD in quadruplicate experiments.

Mentions: IFN╬▒2a is approved by the US FDA as an anticancer drug against CML [11]. K562 cells have been shown to be resistant to interferon treatment in vitro (IC50>105 IU/ml) [12], [13]. To test whether inhibition of EHMT1 and EHMT2 renders K562 cells sensitive to interferon treatment, we measured the proliferation of K562 cells treated with or without IFN╬▒2a in the presence or absence of BIX01294, using a MTT assay. Consistent with previous reports [12], [13], we found that K562 cells were resistant to IFN╬▒2a treatment because treatment with 105 IU/ml of IFN╬▒2a only reduced cell proliferation by 10% (Figure 2A). Interestingly, in the presence of BIX01294, IFN╬▒2a strongly inhibited the proliferation of K562 cells. For example, in the presence of 3 ┬ÁM of BIX01294, 1000 IU/ml of IFN╬▒2a achieved 40% inhibition of cell proliferation and 105 IU/ml of IFN╬▒2a inhibited cell proliferation by 60% (Figure 2A). Moreover, treating K562 cells with 3 ┬ÁM BIX01294 alone had no effect on their proliferation but a higher dose was toxic (data not shown). Our findings demonstrate that inhibition of EHMT1 and EHMT2 sensitizes K562 cells at least by a 100-fold to interferon treatment.


Inhibition of euchromatic histone methyltransferase 1 and 2 sensitizes chronic myeloid leukemia cells to interferon treatment.

Loh SW, Ng WL, Yeo KS, Lim YY, Ea CK - PLoS ONE (2014)

BIX01294 inhibits the proliferation of CML cells.K562 (A), KCL22 (B), BV173 (C) and KT1 (D) cells were cultured with various concentrations of BIX01294 and IFN╬▒2a as indicated. After four days, cell proliferation was measured with a MTT assay. Results represent the mean ┬▒ SD in quadruplicate experiments.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4117596&req=5

pone-0103915-g002: BIX01294 inhibits the proliferation of CML cells.K562 (A), KCL22 (B), BV173 (C) and KT1 (D) cells were cultured with various concentrations of BIX01294 and IFN╬▒2a as indicated. After four days, cell proliferation was measured with a MTT assay. Results represent the mean ┬▒ SD in quadruplicate experiments.
Mentions: IFN╬▒2a is approved by the US FDA as an anticancer drug against CML [11]. K562 cells have been shown to be resistant to interferon treatment in vitro (IC50>105 IU/ml) [12], [13]. To test whether inhibition of EHMT1 and EHMT2 renders K562 cells sensitive to interferon treatment, we measured the proliferation of K562 cells treated with or without IFN╬▒2a in the presence or absence of BIX01294, using a MTT assay. Consistent with previous reports [12], [13], we found that K562 cells were resistant to IFN╬▒2a treatment because treatment with 105 IU/ml of IFN╬▒2a only reduced cell proliferation by 10% (Figure 2A). Interestingly, in the presence of BIX01294, IFN╬▒2a strongly inhibited the proliferation of K562 cells. For example, in the presence of 3 ┬ÁM of BIX01294, 1000 IU/ml of IFN╬▒2a achieved 40% inhibition of cell proliferation and 105 IU/ml of IFN╬▒2a inhibited cell proliferation by 60% (Figure 2A). Moreover, treating K562 cells with 3 ┬ÁM BIX01294 alone had no effect on their proliferation but a higher dose was toxic (data not shown). Our findings demonstrate that inhibition of EHMT1 and EHMT2 sensitizes K562 cells at least by a 100-fold to interferon treatment.

Bottom Line: Chromatin immunoprecipitation assay shows that BIX01294 treatment enhances type I interferon response by reducing H3K9me2 at the promoters of interferon-stimulated genes.Moreover, our data suggest that the expression level of EHMT1 and EHMT2 inversely correlates with the type I interferon responsiveness in CML cell lines.Our study sheds light on the role of EHMT1 and EHMT2 as potential targets in improving the efficacy of standard treatments of CML.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia.

ABSTRACT

Background: H3K9 methylation is one of the essential histone post-translational modifications for heterochromatin formation and transcriptional repression. Recently, several studies have demonstrated that H3K9 methylation negatively regulates the type I interferon response.

Results: We report the application of EHMT1 and EHMT2 specific chemical inhibitors to sensitize CML cell lines to interferon and imatinib treatments. Inhibition of EHMT1 and EHMT2 with BIX01294 enhances the cytotoxicity of IFN╬▒2a in four CML cell lines, K562, KCL22, BV173 and KT1 cells. Chromatin immunoprecipitation assay shows that BIX01294 treatment enhances type I interferon response by reducing H3K9me2 at the promoters of interferon-stimulated genes. Additionally, BIX01294 treatment augments IFN╬▒2a- and imatinib-mediated apoptosis in CML cell lines. Moreover, our data suggest that the expression level of EHMT1 and EHMT2 inversely correlates with the type I interferon responsiveness in CML cell lines.

Conclusions: Our study sheds light on the role of EHMT1 and EHMT2 as potential targets in improving the efficacy of standard treatments of CML.

Show MeSH
Related in: MedlinePlus