The Research Of Different Treatment Sequence In Radiotherapy And Endocrine Therapy In Breast Cancer

Objective:Adjuvant radiotherapy and endocrine therapy have significant role in breast cancer.The concurrent or sequential of the endocrine therapy with radiotherapy has become an essential method.However,the possible outcomes that may be caused by this concurrent orsequential use are still not completely known.Therefore,this research intends to discuss the difference effect and mechanism of different sequence of endocrine therapy and radiotherapy in breast cancer by Meta analysis and vitro experiments.Methods:1.Clinical studies of radiotherapy concurrent and sequential with endocrine therapy in breast cancer were retrieved from 2000 to 2014.The endpoints were radiation-induced toxicityin(cluding upper than grade 2skin-related toxicity,radiation pneumonia and pulmonary fibrosis)and survival rate(including local recurrence,distant metastasis,5-year OS,10-year OS).2.The subject of vitro experiment was ER positive breast cancer cell MCF-7.Experimental groups:control group(C),Fulvestrant group(F),Radiation group(R),add fulvestrant before irradiation group(F + R),add fulvestrant after irradiation group(R + F).By cloning formation,Transwell,flow cytometry and western blot in each group to detecte proliferation,invasion ability,apoptosis,cell cycle and the expression of proteins.Then LY294002 was performed to block PI3K/Akt pathway,repeated the above experiment to find out the role of PI3K/Akt in radiotherapy and endocrine in breast cancer.Results:1.No statistical difference was found in radiation-induced toxicity and survival data between radiation concurrent and sequential with endocrine therapy groups.Stratification analysis was proceeded,grouped by tamoxifen and Al in different treatment timing,however,no statistical difference was found both in radiation-induced toxicity and survival rate.2.1 1)Cloning formation experiment:It showed that the survivalscores of fulvestrant combined irradiation groups were lower than that of radiation group of in(0,2,4,6,8 Gy)each dose;as the dose increased,the survival of the curve of fulvestrant concurrent radiotherapy group was significantly lower than sequential group.2)Transwell:The number of cell through the matrix in group of F.R.F + R and R+ F was significantly increased compared with C group,and the number of cell through the matrix in F + R compared with R + Fgroup was statistically significant,P=0.029,the cell amount of R + F group was higher than the F + R group,the residual breast cancer cell invasion ability in fulvestrant synchronous radiation therapy was weak than sequential group.3)Apoptosis:The apoptosis rate of group F.R.F + R and R + F was significantly increased compared with C group,the highest one was R+F;while compared with each two groups,C vs R+F.R vs R+F.F+R vs R+Fwere statistically significant,P<0.05.4)Cell cycle:It was appeared G1,G2/M arrest and decrease in S in group F,R,F+R,R+F when compared with group C,all of the four groups in Gl,G2/M and S were statistically significant,P<0.05;F+R vs R+F,P>0.05.5)Western blot:The expression of protein Akt,p-Akt473,p-Akt307 was significant decreased in group F+R and R+F compared with group C,the expression of Akt and p-Akt307 in group R were higher than group C,this may caused by radiation induced Akt excitation;the expression of ER-a were all reduced in groups which had fulvestrant,especially in group F+R,which was lowest one;the expression of PCNA were decreased in group F+R and R+F;the expression of MMP-2 were increased in group F,R,F+R and R+F when compared with group C.2.2 1)After PI3K/Akt pathway blocking,Cloning formation experiment:the survival rate in group F+R and R+F were higher than group R in all does;when compared with PI3K/Akt pathway unblocking,the survival rate in group R was highest,group R(PI3K/Akt pathway blocking)was lowest,others in mediate.2)Transwell:The number of cell through the matrix in group F?R?F + R and R +F was significantly decreased compared with C group,and the number of cell through the matrix in F + R compared with R + Fgroup was statistically no difference;when compared with PI3K/Akt pathway unblocking,the number of cell through the matrix in all the group in PI3K/Akt pathway blocking were lower than unblocking groups.3)Apoptosis:The apoptosis rates in all groups were no statistically difference;they were decreased compared with PI3K/Akt unblocking groups.4)Cell cycle:It was appeared G1,G2/M arrest in group F,R,F+R,R+F when compared with group C,all of the four groups in G1,G2/M and S were statistically significant compared with group C;there were no statistically difference compared with the groups in PI3K/Akt pathway unblocking in cell cycle arrest,F + R vs R + F,P>0.05.5)Western blot:The expression of ER-? were all reduced in groups which had fulvestrant,especially in group F+R and R+F,the expression of PCNA in group R+F was lowest,the expression of MMP-2 were no difference in all groups;when compared with PI3K/Akt unblocking groups,the expression of ER-? were lower than relevant groups which had fulvestrant,the expression of PCNA and MMP-2 were lower than relevant unblocking groups.Conclusion:1.Radiotherapy concurrent with endocrine therapy didn't increase or decrease neither the incidence of radiation-induced toxicity nor the survival rate compared with that of sequential group;Endocrine therapy drugs didn't influence outcomes in different treatment timing.2.Fulvestrant has radiotherapy sensitization effect,as radiation dose increasing,fulvestrant synchronous radiation can significantly improve the radiosensitivity than sequential;the residual breast cancer cell invasion ability of fulvestrant synchronous radiation was weak than sequential group.Therefore,we conclude that the effect of fulvestrant concurrent radiation may be superior to sequential.3.The radiotherapy sensitization effect of fulvestrant was correlated to the status of PI3K/Akt pathway,PI3K/Akt pathway blocking can increase radiotherapy sensitization of MCF-7 cell effectively.PI3K/Akt pathway blocking can inhibit the invasion ability of MCF-7cell and the residual cell of fulvestrant and irradiation.4.The combination of PI3K/Akt,radiotherapy and endocrine therapy will tremendously increase the treatment efficacy of radiotherapy and endocrine therapy,and the ability of proliferation and invasion were effectively inhibited.