The Effect Of HDAC Inhibitor On Breast Cancer And ERα Expression

Background:Survey data shows that 1.2 million women suffered from breast cancer every year globally,and 0.5 million were dead of this disease.In Europe and North America countries,the morbidity of breast cancer is on the top of women malignant tumors.With the improvement of living standard and changes in lifestyle in our country,the breast cancer morbidity is now increasing obviously.In 2000 China cancer prevention and treatment office reported a survey,1988 to 1992,which showed the breast cancer morbidity in city was higher than rural and increased in Shanghai year by year,that proved breast cancer is the most common disease in women tumors.Therefore,the prophylaxis,early diagnosis,treatment and prognosis review of breast cancer played a great role in nowadays.Through number of prospective clinical study in breast cancer disease,the therapy mode was verified to general combined therapy.Researches suggest estrogen is the important mitosis stimulator in breast cancer,its mitotic promoting action is mediated by estrogen receptor(ER),as a typical ER,ERαpositive is the evidence to endocrine therapy.The effect of endocrine therapy on ER(+)patients was much better than the ER(-)patients.However,there were 1/3 patients tested ER(-)when diagnosed breast cancer,and another part of ER(+)patients converted ER(-)in the process of therapy.This kind of people were incompetent with endocrine therapy and also had poor prognosis.Recent researches indicated that DNMT1 and HDAC were the key regulator to induce ER gene silencing.Their function is mainly about DNA methylation and histone deacetylation.HDAC binding to abnormal promoter can suppress genetic transcription of some functional genes, that might be a mechanism of malignant tumor.HDAC inhibitor aimed directly at HDAC to cure cancer.Objective:1.To investigate the effects of ERαgene in breast cancer and fibroma by evaluating the expression level and expression rate of ERα-mRNA in this two kinds of tissues.Analyze the relationship between ERαexpression rate and other factors to identify the influence factors.2.To investigate the effects of MS-275,a sort of histone deacetylation inhibitor,acting on breast cancer cells MDA-MB-231 and MCF-7 by making ERαexpression level increase or re-express.3.To investigate the effects of MS-275 on proliferation and apoptosis of breast cancer cells.Methods:1.The ERα-mRNA level of breast cancer and breast fibroma was measured by RT-PCR.2.Breast cancer cells were treated with MS-275 at 1.0μmol/L for 48hrs,ERαmRNA level was measured by RT-PCR in breast cancer cells before or after the treatment.3.Treat breast cancer cells with MS-275 at different concentration(0.25μmol/L,0.5μmol/L,1.0μmol/L,2.5μmol/L),at the same time set the control group to compare.Draw the cells growing inhibiting curves by MTT test after the medicine intervention.Then observe the biological behavior of breast cancer cells using Flow Cytometry method.Results:1.The mRNA level of ERαin breast cancer was higher than in breast fibroma,but the expression rate in this two kinds of tissues had no significant differences.And in breast cancer,the ERa had no business with age and menstruation,it definitely related to clinical stage and lymph nodes metastasis or else.2.MDA-MB-231,ER-negative breast cancer cell,re-express ERαmRNA after treated with 1.0μmol/L MS-275 for 48hrs.MCF-7, ER-positive breast cancer cells,got an increased expression after the same treatment.And they all had significant differences.3.MS-275 as a histone de-acetylation inhibitor could inhibit the growth of breast cancer cells significantly and its inhibiting effect contributed to the concentration and function time proved by MTT test. Tested by Flow Cytometry method,MS-275 can suspended the breast cancer cells generation at G1/S and G2/M period.This HDAC inhibitor also induce breast cancer cells apoptosis viewed by electron microscope.Conclusions1.HADC inhibitor can induce ER-negative breast cancer cells re-express ERα.2.MS-275,as a histone de-acetylation inhibitor,mostly depended on cell apoptosis and cell cycle block to perform its anti-tumor effect.