Limits...
Transcriptional regulation of the p73 gene by Nrf-2 and promoter CpG methylation in human breast cancer.

Lai J, Nie W, Zhang W, Wang Y, Xie R, Wang Y, Gu J, Xu J, Song W, Yang F, Huang G, Cao P, Guan X - Oncotarget (2014)

Bottom Line: However, we found Nrf-2 induced ΔNp73 expression was abolished with 5-aza-dC treatment, thus lead to a down-regulated ΔNp73 and an up-regulated TAp73 expression in breast cancer cells lines.A significant inverse correlation was found between TAp73 and ΔNp73 expression in the above tissue-array (P = 0.047) and validated in another set consisting of 128 breast cancer tumor tissue (P = 0.034).Taken together, our findings suggest that Nrf-2 and promoter methylation cooperatively govern the transcriptional regulation of p73, and unbalanced expression of TAp73 and ΔNp73 expression plays a critical role in breast cancer development.

View Article: PubMed Central - PubMed

Affiliation: Department of Medical Oncology, Jinling Hospital, School of Medicine, Southern Medical University, Guangzhou, China; These authors contributed equally to this work.

ABSTRACT
To understand the transcriptional regulation of p73 by promoter methylation and Nrf-2 in breast carcinogenesis, ChIP assay indicated that Nrf-2 can bind to both promoters and can activate the transcription of TAp73 and ΔNp73 in MCF-7 cell line, knockdown of Nrf-2 gene resulted in an abrogation of TAp73 and ΔNp73 expression in the cells transfected with sh-Nrf-2 as well as Nrf-2 knock out mouse model. However, we found Nrf-2 induced ΔNp73 expression was abolished with 5-aza-dC treatment, thus lead to a down-regulated ΔNp73 and an up-regulated TAp73 expression in breast cancer cells lines. Consistent with this model, we detected decreased TAp73 and increased ΔNp73 expression in breast cancer tissue, along with increased TAp73 but decreased ΔNp73 expression in corresponding surrounding noncancerous tissues (NCTs) in a breast cancer tissue assay. A significant inverse correlation was found between TAp73 and ΔNp73 expression in the above tissue-array (P = 0.047) and validated in another set consisting of 128 breast cancer tumor tissue (P = 0.034). Taken together, our findings suggest that Nrf-2 and promoter methylation cooperatively govern the transcriptional regulation of p73, and unbalanced expression of TAp73 and ΔNp73 expression plays a critical role in breast cancer development.

Show MeSH

Related in: MedlinePlus

5-aza-dC induces cell proliferation inhibition along with cycle arrest and apoptosis(A) Cell viability were measured with MTT after MCF-7, SK-BR-3 and MDA-MB-231 were treated with 5-aza-dC at various concentrations for 48h. Results are presented as the mean ± SD of triplicate observations, P<0.05 controlled with untreated group in the three cell lines. (B) Cell cycle distribution was determined by flow cytometry analysis using PI staining after treatment with 5-aza-dC for 48h at the indicated concentrations. (C) Cell apoptosis was detected by flow cytometry analysis after the cells were treated by the same treatment as B. Results are presented as the mean ± SD of triplicate observations. *P < 0.05 or **P < 0.001.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4196172&req=5

Figure 1: 5-aza-dC induces cell proliferation inhibition along with cycle arrest and apoptosis(A) Cell viability were measured with MTT after MCF-7, SK-BR-3 and MDA-MB-231 were treated with 5-aza-dC at various concentrations for 48h. Results are presented as the mean ± SD of triplicate observations, P<0.05 controlled with untreated group in the three cell lines. (B) Cell cycle distribution was determined by flow cytometry analysis using PI staining after treatment with 5-aza-dC for 48h at the indicated concentrations. (C) Cell apoptosis was detected by flow cytometry analysis after the cells were treated by the same treatment as B. Results are presented as the mean ± SD of triplicate observations. *P < 0.05 or **P < 0.001.

Mentions: To investigate the effect of 5-aza-dC in breast cancer, we analyzed the induction of cell proliferation inhibition in three breast cancer cell lines including MCF-7, SK-BR-3 and MDA-MB-231 treated with increasing concentrations of 5-aza-dC (0–160μmol/L) for 48 h. As shown in Figure 1A, dose-dependent inhibitions of cell proliferation were observed in the three breast cancer cell lines, and the cell viability was decreased by about 50% when the MCF-7 cells was treated with the 5-aza-dC at 20μmol/L for 48 h (P< 0.05). Hence, we selected the MCF-7 cells treated with 0-20μmol/L 5-aza-dC for 48 h for the further studies.


Transcriptional regulation of the p73 gene by Nrf-2 and promoter CpG methylation in human breast cancer.

Lai J, Nie W, Zhang W, Wang Y, Xie R, Wang Y, Gu J, Xu J, Song W, Yang F, Huang G, Cao P, Guan X - Oncotarget (2014)

5-aza-dC induces cell proliferation inhibition along with cycle arrest and apoptosis(A) Cell viability were measured with MTT after MCF-7, SK-BR-3 and MDA-MB-231 were treated with 5-aza-dC at various concentrations for 48h. Results are presented as the mean ± SD of triplicate observations, P<0.05 controlled with untreated group in the three cell lines. (B) Cell cycle distribution was determined by flow cytometry analysis using PI staining after treatment with 5-aza-dC for 48h at the indicated concentrations. (C) Cell apoptosis was detected by flow cytometry analysis after the cells were treated by the same treatment as B. Results are presented as the mean ± SD of triplicate observations. *P < 0.05 or **P < 0.001.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4196172&req=5

Figure 1: 5-aza-dC induces cell proliferation inhibition along with cycle arrest and apoptosis(A) Cell viability were measured with MTT after MCF-7, SK-BR-3 and MDA-MB-231 were treated with 5-aza-dC at various concentrations for 48h. Results are presented as the mean ± SD of triplicate observations, P<0.05 controlled with untreated group in the three cell lines. (B) Cell cycle distribution was determined by flow cytometry analysis using PI staining after treatment with 5-aza-dC for 48h at the indicated concentrations. (C) Cell apoptosis was detected by flow cytometry analysis after the cells were treated by the same treatment as B. Results are presented as the mean ± SD of triplicate observations. *P < 0.05 or **P < 0.001.
Mentions: To investigate the effect of 5-aza-dC in breast cancer, we analyzed the induction of cell proliferation inhibition in three breast cancer cell lines including MCF-7, SK-BR-3 and MDA-MB-231 treated with increasing concentrations of 5-aza-dC (0–160μmol/L) for 48 h. As shown in Figure 1A, dose-dependent inhibitions of cell proliferation were observed in the three breast cancer cell lines, and the cell viability was decreased by about 50% when the MCF-7 cells was treated with the 5-aza-dC at 20μmol/L for 48 h (P< 0.05). Hence, we selected the MCF-7 cells treated with 0-20μmol/L 5-aza-dC for 48 h for the further studies.

Bottom Line: However, we found Nrf-2 induced ΔNp73 expression was abolished with 5-aza-dC treatment, thus lead to a down-regulated ΔNp73 and an up-regulated TAp73 expression in breast cancer cells lines.A significant inverse correlation was found between TAp73 and ΔNp73 expression in the above tissue-array (P = 0.047) and validated in another set consisting of 128 breast cancer tumor tissue (P = 0.034).Taken together, our findings suggest that Nrf-2 and promoter methylation cooperatively govern the transcriptional regulation of p73, and unbalanced expression of TAp73 and ΔNp73 expression plays a critical role in breast cancer development.

View Article: PubMed Central - PubMed

Affiliation: Department of Medical Oncology, Jinling Hospital, School of Medicine, Southern Medical University, Guangzhou, China; These authors contributed equally to this work.

ABSTRACT
To understand the transcriptional regulation of p73 by promoter methylation and Nrf-2 in breast carcinogenesis, ChIP assay indicated that Nrf-2 can bind to both promoters and can activate the transcription of TAp73 and ΔNp73 in MCF-7 cell line, knockdown of Nrf-2 gene resulted in an abrogation of TAp73 and ΔNp73 expression in the cells transfected with sh-Nrf-2 as well as Nrf-2 knock out mouse model. However, we found Nrf-2 induced ΔNp73 expression was abolished with 5-aza-dC treatment, thus lead to a down-regulated ΔNp73 and an up-regulated TAp73 expression in breast cancer cells lines. Consistent with this model, we detected decreased TAp73 and increased ΔNp73 expression in breast cancer tissue, along with increased TAp73 but decreased ΔNp73 expression in corresponding surrounding noncancerous tissues (NCTs) in a breast cancer tissue assay. A significant inverse correlation was found between TAp73 and ΔNp73 expression in the above tissue-array (P = 0.047) and validated in another set consisting of 128 breast cancer tumor tissue (P = 0.034). Taken together, our findings suggest that Nrf-2 and promoter methylation cooperatively govern the transcriptional regulation of p73, and unbalanced expression of TAp73 and ΔNp73 expression plays a critical role in breast cancer development.

Show MeSH
Related in: MedlinePlus