Limits...
Metastasis-associated protein 1 is an upstream regulator of DNMT3a and stimulator of insulin-growth factor binding protein-3 in breast cancer

View Article: PubMed Central - PubMed

ABSTRACT

Despite a recognized role of DNA methyltransferase 3a (DNMT3a) in human cancer, the nature of its upstream regulator(s) and relationship with the master chromatin remodeling factor MTA1, continues to be poorly understood. Here, we found an inverse relationship between the levels of MTA1 and DNMT3a in human cancer and that high levels of MTA1 in combination of low DNMT3a status correlates well with poor survival of breast cancer patients. We discovered that MTA1 represses DNMT3a expression via HDAC1/YY1 transcription factor complex. Because IGFBP3 is an established target of DNMT3a, we investigated the effect of MTA1 upon IGFBP3 expression, and found a coactivator role of MTA1/c-Jun/Pol II coactivator complex upon the IGFBP3 transcription. In addition, MTA1 overexpression correlates well with low levels of DNMT3a which, in turn also correlates with a high IGFBP3 status in breast cancer patients and predicts a poor clinical outcome for breast cancer patients. These findings suggest that MTA1 could regulate the expression of IGFBP3 in both DNMT3a-dependent and -independent manner. Together findings presented here recognize an inherent role of MTA1 as a modifier of DNMT3a and IGFBP3 expression, and consequently, the role of MTA1-DNMT3a-IGFBP3 axis in breast cancer progression.

No MeSH data available.


MTA1 represses DNMT3a transcription.(A) DNMT3a promoter activity in MCF-7/pcDNA3.1 and in MCF-7/T7-MTA1 cells. (B) DNMT3a promoter activity in MCF-7 and in MTA1-silenced MCF-7 cells. MCF-7 cells were transfected with pGL3-DNMT3a along with siMTA1 and DNMT3a-promo-Luc activity was measured. (C) DNMT3a promoter activity in MTA1+/+ and MTA1−/− MEFs. (D,E) Recruitment of MTA1 or HDACs or YYI or MTA1/HDAC1 or MTA1/YY1 complexes onto the DNMT3a promoter in MCF-7 cells as analyzed by ChIP or sequential ChIP (F). The effect of YY1 on DNMT3a-promoter activity was measured in MCF-7 cells. Results were presented in terms of relative luciferase activity and the values represent the mean of ± s.d. from three independent transfection experiments.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC5385551&req=5

f4: MTA1 represses DNMT3a transcription.(A) DNMT3a promoter activity in MCF-7/pcDNA3.1 and in MCF-7/T7-MTA1 cells. (B) DNMT3a promoter activity in MCF-7 and in MTA1-silenced MCF-7 cells. MCF-7 cells were transfected with pGL3-DNMT3a along with siMTA1 and DNMT3a-promo-Luc activity was measured. (C) DNMT3a promoter activity in MTA1+/+ and MTA1−/− MEFs. (D,E) Recruitment of MTA1 or HDACs or YYI or MTA1/HDAC1 or MTA1/YY1 complexes onto the DNMT3a promoter in MCF-7 cells as analyzed by ChIP or sequential ChIP (F). The effect of YY1 on DNMT3a-promoter activity was measured in MCF-7 cells. Results were presented in terms of relative luciferase activity and the values represent the mean of ± s.d. from three independent transfection experiments.

Mentions: To study the mechanism of MTA1 modulation of DNMT3a expression, we next measured the transcription of DNMT3a using a DNMT3a-prom-luc reporter system19 in MCF-7 cells under conditions of with or without MTA1 overexpression. We noticed a substantial repression of DNMT3a-prom-luc activity by MTA1 overexpression as compared to the control MCF-7 cells (Fig. 4A). Similarly, we observed an increase in DNMT3a-prom-luc activity when MTA1 is silenced in MCF-7 cells (Fig. 4B). Consistent with these results, the basal DNMT3a-prom-luc activity increases by about 4-fold in MTA1-KO MEF as compared to the wild-type MEF (Fig. 4C).


Metastasis-associated protein 1 is an upstream regulator of DNMT3a and stimulator of insulin-growth factor binding protein-3 in breast cancer
MTA1 represses DNMT3a transcription.(A) DNMT3a promoter activity in MCF-7/pcDNA3.1 and in MCF-7/T7-MTA1 cells. (B) DNMT3a promoter activity in MCF-7 and in MTA1-silenced MCF-7 cells. MCF-7 cells were transfected with pGL3-DNMT3a along with siMTA1 and DNMT3a-promo-Luc activity was measured. (C) DNMT3a promoter activity in MTA1+/+ and MTA1−/− MEFs. (D,E) Recruitment of MTA1 or HDACs or YYI or MTA1/HDAC1 or MTA1/YY1 complexes onto the DNMT3a promoter in MCF-7 cells as analyzed by ChIP or sequential ChIP (F). The effect of YY1 on DNMT3a-promoter activity was measured in MCF-7 cells. Results were presented in terms of relative luciferase activity and the values represent the mean of ± s.d. from three independent transfection experiments.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5385551&req=5

f4: MTA1 represses DNMT3a transcription.(A) DNMT3a promoter activity in MCF-7/pcDNA3.1 and in MCF-7/T7-MTA1 cells. (B) DNMT3a promoter activity in MCF-7 and in MTA1-silenced MCF-7 cells. MCF-7 cells were transfected with pGL3-DNMT3a along with siMTA1 and DNMT3a-promo-Luc activity was measured. (C) DNMT3a promoter activity in MTA1+/+ and MTA1−/− MEFs. (D,E) Recruitment of MTA1 or HDACs or YYI or MTA1/HDAC1 or MTA1/YY1 complexes onto the DNMT3a promoter in MCF-7 cells as analyzed by ChIP or sequential ChIP (F). The effect of YY1 on DNMT3a-promoter activity was measured in MCF-7 cells. Results were presented in terms of relative luciferase activity and the values represent the mean of ± s.d. from three independent transfection experiments.
Mentions: To study the mechanism of MTA1 modulation of DNMT3a expression, we next measured the transcription of DNMT3a using a DNMT3a-prom-luc reporter system19 in MCF-7 cells under conditions of with or without MTA1 overexpression. We noticed a substantial repression of DNMT3a-prom-luc activity by MTA1 overexpression as compared to the control MCF-7 cells (Fig. 4A). Similarly, we observed an increase in DNMT3a-prom-luc activity when MTA1 is silenced in MCF-7 cells (Fig. 4B). Consistent with these results, the basal DNMT3a-prom-luc activity increases by about 4-fold in MTA1-KO MEF as compared to the wild-type MEF (Fig. 4C).

View Article: PubMed Central - PubMed

ABSTRACT

Despite a recognized role of DNA methyltransferase 3a (DNMT3a) in human cancer, the nature of its upstream regulator(s) and relationship with the master chromatin remodeling factor MTA1, continues to be poorly understood. Here, we found an inverse relationship between the levels of MTA1 and DNMT3a in human cancer and that high levels of MTA1 in combination of low DNMT3a status correlates well with poor survival of breast cancer patients. We discovered that MTA1 represses DNMT3a expression via HDAC1/YY1 transcription factor complex. Because IGFBP3 is an established target of DNMT3a, we investigated the effect of MTA1 upon IGFBP3 expression, and found a coactivator role of MTA1/c-Jun/Pol II coactivator complex upon the IGFBP3 transcription. In addition, MTA1 overexpression correlates well with low levels of DNMT3a which, in turn also correlates with a high IGFBP3 status in breast cancer patients and predicts a poor clinical outcome for breast cancer patients. These findings suggest that MTA1 could regulate the expression of IGFBP3 in both DNMT3a-dependent and -independent manner. Together findings presented here recognize an inherent role of MTA1 as a modifier of DNMT3a and IGFBP3 expression, and consequently, the role of MTA1-DNMT3a-IGFBP3 axis in breast cancer progression.

No MeSH data available.