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Long Term Exposure to Polyphenols of Artichoke (Cynara scolymus L.) Exerts Induction of Senescence Driven Growth Arrest in the MDA-MB231 Human Breast Cancer Cell Line.

Mileo AM, Di Venere D, Abbruzzese C, Miccadei S - Oxid Med Cell Longev (2015)

Bottom Line: Furthermore, AEs exposure induces a significant increase of senescence-associated β-galactosidase (SA-β-gal) staining and upregulation of tumour suppressor genes, p16(INK4a) and p21(Cip1/Waf1) in MDA-MB231 cells.Inhibition of ROS generation by N-acetylcysteine (NAC) attenuates the antiproliferative effect.Our results suggest that artichoke polyphenols could be a promising dietary tool either in cancer chemoprevention or/and in cancer treatment as a nonconventional, adjuvant therapy.

View Article: PubMed Central - PubMed

Affiliation: Regina Elena National Cancer Institute, Via Elio Chianesi 53, 00144 Rome, Italy.

ABSTRACT
Polyphenolic extracts from the edible part of artichoke (Cynara scolymus L.) have been shown to be potential chemopreventive and anticancer dietary compounds. High doses of polyphenolic extracts (AEs) induce apoptosis and decrease the invasive potential of the human breast cancer cell line, MDA-MB231. However, the molecular mechanism underlying AEs antiproliferative effects is not completely understood. We demonstrate that chronic and low doses of AEs treatment at sublethal concentrations suppress human breast cancer cell growth via a caspases-independent mechanism. Furthermore, AEs exposure induces a significant increase of senescence-associated β-galactosidase (SA-β-gal) staining and upregulation of tumour suppressor genes, p16(INK4a) and p21(Cip1/Waf1) in MDA-MB231 cells. AEs treatment leads to epigenetic alterations in cancer cells, modulating DNA hypomethylation and lysine acetylation levels in total proteins. Cell growth arrest correlates with increased reactive oxygen species (ROS) production in AEs treated breast cancer cells. Inhibition of ROS generation by N-acetylcysteine (NAC) attenuates the antiproliferative effect. These findings demonstrate that chronic AEs treatment inhibits breast cancer cell growth via the induction of premature senescence through epigenetic and ROS-mediated mechanisms. Our results suggest that artichoke polyphenols could be a promising dietary tool either in cancer chemoprevention or/and in cancer treatment as a nonconventional, adjuvant therapy.

No MeSH data available.


Related in: MedlinePlus

Effect of AEs on global DNA methylation levels in MDA-MB231 cells. Low doses of AEs (2.5–30 μM) for 10 days treatment decreased levels of 5-mC, 5-methylcytosine, in a dose-dependent manner. 5-mC specific antibody was used for (a) and (b) cytostaining and (c) for dot blot analysis on genomic DNA. (a) The image shown is representative of at least three independent experiments. Scale bar: 100 μm. (b) The 5-methylcytosine positive cells versus total cells were counted by using an inverted microscope (20x) and the results are reported as mean ± SD. (c) The intensity of individual DNA dots shown was quantified by densitometry.
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fig4: Effect of AEs on global DNA methylation levels in MDA-MB231 cells. Low doses of AEs (2.5–30 μM) for 10 days treatment decreased levels of 5-mC, 5-methylcytosine, in a dose-dependent manner. 5-mC specific antibody was used for (a) and (b) cytostaining and (c) for dot blot analysis on genomic DNA. (a) The image shown is representative of at least three independent experiments. Scale bar: 100 μm. (b) The 5-methylcytosine positive cells versus total cells were counted by using an inverted microscope (20x) and the results are reported as mean ± SD. (c) The intensity of individual DNA dots shown was quantified by densitometry.

Mentions: DNA hypermethylation is a major epigenetic modification that leads to silencing of tumour suppressor genes which may contribute to cancer development and progression [46]. Recent investigations suggest that some dietary phytochemicals may prevent cancer by modulating epigenetic processes [35, 47]. To examine whether chronic treatment has epigenetic effects on the DNA methylation level, cells were exposed to increasing concentrations of AEs, as shown in Figure 4. After 10 days, cells were harvested for immunocytostaining of DNA methylation using an antibody specific to 5-methylcytosine (5-mC). Treatment of AEs resulted in a reduced number of 5-mC-positive cells in a dose-dependent manner compared to untreated cells (Figures 4(a) and 4(b)).


Long Term Exposure to Polyphenols of Artichoke (Cynara scolymus L.) Exerts Induction of Senescence Driven Growth Arrest in the MDA-MB231 Human Breast Cancer Cell Line.

Mileo AM, Di Venere D, Abbruzzese C, Miccadei S - Oxid Med Cell Longev (2015)

Effect of AEs on global DNA methylation levels in MDA-MB231 cells. Low doses of AEs (2.5–30 μM) for 10 days treatment decreased levels of 5-mC, 5-methylcytosine, in a dose-dependent manner. 5-mC specific antibody was used for (a) and (b) cytostaining and (c) for dot blot analysis on genomic DNA. (a) The image shown is representative of at least three independent experiments. Scale bar: 100 μm. (b) The 5-methylcytosine positive cells versus total cells were counted by using an inverted microscope (20x) and the results are reported as mean ± SD. (c) The intensity of individual DNA dots shown was quantified by densitometry.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4477242&req=5

fig4: Effect of AEs on global DNA methylation levels in MDA-MB231 cells. Low doses of AEs (2.5–30 μM) for 10 days treatment decreased levels of 5-mC, 5-methylcytosine, in a dose-dependent manner. 5-mC specific antibody was used for (a) and (b) cytostaining and (c) for dot blot analysis on genomic DNA. (a) The image shown is representative of at least three independent experiments. Scale bar: 100 μm. (b) The 5-methylcytosine positive cells versus total cells were counted by using an inverted microscope (20x) and the results are reported as mean ± SD. (c) The intensity of individual DNA dots shown was quantified by densitometry.
Mentions: DNA hypermethylation is a major epigenetic modification that leads to silencing of tumour suppressor genes which may contribute to cancer development and progression [46]. Recent investigations suggest that some dietary phytochemicals may prevent cancer by modulating epigenetic processes [35, 47]. To examine whether chronic treatment has epigenetic effects on the DNA methylation level, cells were exposed to increasing concentrations of AEs, as shown in Figure 4. After 10 days, cells were harvested for immunocytostaining of DNA methylation using an antibody specific to 5-methylcytosine (5-mC). Treatment of AEs resulted in a reduced number of 5-mC-positive cells in a dose-dependent manner compared to untreated cells (Figures 4(a) and 4(b)).

Bottom Line: Furthermore, AEs exposure induces a significant increase of senescence-associated β-galactosidase (SA-β-gal) staining and upregulation of tumour suppressor genes, p16(INK4a) and p21(Cip1/Waf1) in MDA-MB231 cells.Inhibition of ROS generation by N-acetylcysteine (NAC) attenuates the antiproliferative effect.Our results suggest that artichoke polyphenols could be a promising dietary tool either in cancer chemoprevention or/and in cancer treatment as a nonconventional, adjuvant therapy.

View Article: PubMed Central - PubMed

Affiliation: Regina Elena National Cancer Institute, Via Elio Chianesi 53, 00144 Rome, Italy.

ABSTRACT
Polyphenolic extracts from the edible part of artichoke (Cynara scolymus L.) have been shown to be potential chemopreventive and anticancer dietary compounds. High doses of polyphenolic extracts (AEs) induce apoptosis and decrease the invasive potential of the human breast cancer cell line, MDA-MB231. However, the molecular mechanism underlying AEs antiproliferative effects is not completely understood. We demonstrate that chronic and low doses of AEs treatment at sublethal concentrations suppress human breast cancer cell growth via a caspases-independent mechanism. Furthermore, AEs exposure induces a significant increase of senescence-associated β-galactosidase (SA-β-gal) staining and upregulation of tumour suppressor genes, p16(INK4a) and p21(Cip1/Waf1) in MDA-MB231 cells. AEs treatment leads to epigenetic alterations in cancer cells, modulating DNA hypomethylation and lysine acetylation levels in total proteins. Cell growth arrest correlates with increased reactive oxygen species (ROS) production in AEs treated breast cancer cells. Inhibition of ROS generation by N-acetylcysteine (NAC) attenuates the antiproliferative effect. These findings demonstrate that chronic AEs treatment inhibits breast cancer cell growth via the induction of premature senescence through epigenetic and ROS-mediated mechanisms. Our results suggest that artichoke polyphenols could be a promising dietary tool either in cancer chemoprevention or/and in cancer treatment as a nonconventional, adjuvant therapy.

No MeSH data available.


Related in: MedlinePlus