The Role Of EZH2 For The Proliferation Of ER Positive Breast Cancer Cells And The Intervention Effect Of Resveratrol

The proliferation of ER positive breast cancer depends on estrogen and estrogen receptor?ER?,estrogen activates ER and its target genes by binding to ER to stimulate the growth of tumor.EZH2 is highly expressed in a variety of tumors,including breast cancer,and plays an important role in the occurrence and development of breast cancer.EZH2 is the core subunit of the enzyme activity of polycomb repressive complex 2?PRC2?,which can catalyze the methylation of histone H3K27 to play the function of gene silencing.In addition,EZH2 can also play a direct role indepedent on H3K27me3.Studies have shown that in ER positive breast cancer cells,EZH2 can connect ER and Wnt signals and jointly promote the prolifertion of cells.However,the regulation of EZH2 on ER signal is not clear.Resveratrol is widely found in various natural foods,such as grapes,peanuts,strawberries and soybeans.A large number of in vivo and in vitro studies had shown that resveratrol had a remarkable anti-tumor effect on ER positive breast cancer.Study reported that many plant chemicals can play a variety of anti-cancer function by inhibiting the expressionon of EZH2,high expression of EZH2 could inhibit the ER signal in the triple negative breast cancer or drug-resistance breast cancer,but in the ER positive breast cancer,the role of EZH2 to ER signal was not clear.Therefore,understanding the regulation of EZH2 on ER signal and its role in resveratrol against ER positive breast cancer can provide further ideas and strategies for the treatment of ER positive breast cancer.Objective:This study adopts the ER positive breast cancer cells MCF-7and T47D as the research object to study the role of EZH2 in breast cancer proliferation and the intervention effect of resveratrol,to provide new evidence for EZH2 as therapeutic targets of ER positive breast cancer cells and provides a new theory for resveratrol as a drug applied to clinical to treat ER positive breast cancer.Methods:CCK-8 experiment and cell plate cloning were used to detect cell proliferation.The mRNA level of the target ge ne was detected by real-time quantitative PCR.The protein level of the target gene was detected by the protein immunoblotting assay.The cell transient transfection experiment was used to knock down EZH2.Results:?1?The role of EZH2 in the proliferation of ER positive breast cancer cells:CCK-8 assay results showed that the E₂ can promote the proliferation of ER positive reast cancer cells MCF-7 and T47D cells,and this effect could be blocked by ER antagonists ICI,showing the proliferation of ER positive breast cancer cells was dependent on ER.Under the stimulation of E2?0-10 nM?,the level mRN A and protein expression of the of EZH2 in the cells increased,and knockout EZH2 caused the proliferation of cells to slow down,which could reverse the promoting effect E₂ on cell proliferation.In addition,inhibition of EZH2 expression can inhibit the expression of ER protein and mRN A of target genes pS2.The ER antagonist ICI could also block promotion of E₂ on EZH2 mRNA and protein.E₂ could activate the phosphorylation of ERK1/2 in cells,and the ERK1/2 signal inhibitor U0126 can block the promoting effect of E₂ on cell proliferation,and can also reverse induction of EZH2 expression of E_2.?2?The role of EZH2 in the inhibition effect of REV in the proliferation of ER positive breast cancer cells:Using resveratrol?0-80?M?to treat ER positive breast cancer cells,CCK 8 experime nts showed cell proliferation was inhibited,the results of the Real Time Quantitative PCR and western blotting assay showed that resveratrol could reduce cells the mRNA and protein level of EZH2,using siRNA knockout EZH2 or EZH2 inhibitor DZNep could weaken the resveratrol inhibition effect of cell proliferation.The results of western blotting assay showed that resveratrol could reduce the expression of p-ERK1/2.The ERK1/2 signal inhibitor U0126 could weaken the resveratrol inhibition of cell proliferation,at the same time also can weaken the resveratrol inhibition of EZH2.In addition,resveratrol also reduced the phosphorylation of STAT3 and phosphorylation of AKT in cells,but the STAT3 signal inhibitor stattic and the PI3K/AKT signal inhibitor LY294002 did not affect the expression of EZH2 in cel s.Conclusion:In ER positive breast cancer cells,the E₂ could activate ERK1/2 signal to enhance the expression of EZH2 to activate ER signal,thus promoting cell proliferation,and resveratrol could inhibit cell proliferation by inhibiting ERK1/2signal and the expression of EZH2.