| Breast cancer is a common malignant tumor in women around the world,of which the incidence and mortality are increasing year by year recently.It is of significance to prevent and treat breast cancer for reducing its incidence,increasing the survival rate of breast cancer patients and improving their living quality.At present,it is believed that the occurrence and development of breast cancer are related to many factors,among which nutrition is a definite factor,since certain nutrients can inhibit breast cancer.Taurine(Tau)is a sulfur-containing non-protein amino acid,which is conditionally essential.It has multiple physiological functions in the body on nerve,cardiovascular system,immunity,endocrinology & metabolism,and motor system.The recent studies show that taurine can inhibit breast cancer to a certain extent,but relevant mechanism is still unclear,which may relate to anti-oxidation,immunity enhancement and inducing apoptosis of tumor cells.The present study is about analyzing relevant mechanism of taurine intervening breast cancer from different perspectives with multiple methods,which is divided into four parts:(1)Intervention effect of taurine on the occurrence of breast cancer of rats.Water added with 3% taurine was given to rats with breast cancer,and indicators are observed such as the growth of tumor,the effect of high-fat diet on breast cancer rat models,as well as the changes of seventeen kinds of amino acid in the whole blood of breast cancer rats and taurine-treated breast cancer rats.(2)Metabolomics analysis of taurine-treated breast cancer rats.The metabolomics mechanism was analyzed for breast cancer rats and taurine-treated breast cancer rat from the perspective of metabolic changes,and differential metabolites and related metabolic pathways were determined.(3)Gene analysis of taurine-treated breast cancer rats.Real-time fluorescent quantitative PCR technique was utilized to study related genes,from which the mechanism of taurine intervening breast cancer was analyzed.(4)Detection and analysis of intestinal microflora of taurine-treated breast cancer rats.DNA was extracted from the colonic contents of rats for high-throughput 16 Sr DNA sequencing to study the changes in the intestinal microflora of both breast cancer rats and aurine-treated breast cancer rats.?.Objectives1.To observe the intervention effect of taurine on DMBA-induced breast cancer rat models.2.To analyze metabolomics changes in plasma of taurine-treated breast cancer rats.3.To analyze related genetic changes of taurine-treated breast cancer rats.4.To study the change rule for intestinal microflora of breast cancer rats and taurine-treated breast cancer rats.The study and analysis above of relevant mechanism of taurine intervening breast cancer will provide theoretical basis for the study on taurine treatment of breast cancer.?.Materials and methods1.Divide 80 SD female rats randomly into six groups: Group 1 of 10 rats(normal control group),Group 2 of 10 rats(gavage with peanut oil),Group 3 of15 rats(DMBA-induced group),Group 4 of 15 rats(group induced by DMBA +high-fat diet),Group 5 of 15 rats(DMBA-induced group with taurine intervention),and Group 6 of 15 rats(DMBA-induced + high-fat diet with taurine intervention).The high-fat diet was to add 5% lard into the feed,and the taurine intervention was to add 3% taurine(food grade)into the drinking water for the rats.Observe the weight change and tumor growth of rats.Terminate the experiment after 16 weeks,and kill all rats to strip the tumor tissues and take blood sample.To reduce confounding factors,take Group 1,3 and 5 for studying and analyzing the taurine intervention mechanism,Group 4 and 6 for subsequent experiment and analysis,and Group 2 as control group of DMBA solvent.The experiment results indicated that the peanut oil had no effect on the models,thus the samples would not be analyzed temporarily.Take the whole blood of normal control group 1(n=10),DMBA-induced group 3(n=10)and DMBA-induced group 5 with taurine intervention(n=10),and use an automatic amino acid analyzer for analyzing the seventeen kinds of amino acid.2.Take the plasma of normal control group 1(n=10),DMBA-induced group 3(n=10)and DMBA-induced group 5 with taurine intervention(n=8),make metabolomics analysis by means of GC-MS method,separate and identify differential metabolites by means of OPLS-DA and T-test,and analyze related metabolic pathways of differential metabolites by utilizing KEEG database.3.Respectively take the breast tissue or tumor tissue of the rats from normal control group 1(n=6),DMBA-induced group 3(n=6)and DMBA-induced group 5 with taurine intervention(n=6),and extract the RNA to reversely transcript into c DNA.Detect relevant breast cancer genes of 7 rats by real-time fluorescent quantitative PCR technique: Akt1,Igf1,Igf1 r,Pten,Myc,Hif-1a,HK-2.4.Respectively take the colonic contents of the rats from normal control group 1(n=8),DMBA-induced group 3(n=6)and DMBA-induced group 5 with taurine intervention(n=5),extract the DNA and explore the changes in intestinal microflora of breast cancer rats and taurine-treated breast cancer rats by high-throughput 16 Sr DNA sequencing.?.Results1.Through comparison of tumor incidences among the groups,the highest incidence in Group 6 was 100%,80% in Group 3 and 4,and the incidence in Group 5 is the lowest.By comparing the incubation,it was found the shortest in Group 4 and the longest in Group 5.By comparing the total tumor-bearing number and tumor size of each group,the rats of Group 6 bear the most tumors,while Group 5 bears the least tumors.Calculating the sums of long diameters and long & short diameters of each rat for reflecting the tumor size,the rats of Group 4 had the largest tumor,while Group 5 had the smallest tumor.Comparing DMBA-induced group 3 and normal control group 1,the methionine,isoleucine,tyrosine,and phenylalanine among the amino acids in the whole blood were increasing,and the difference was statistically significant;the aspartic acid,serine,glutamic acid,glycine,lanine,cystine,valine,lysine,histidine,and arginine were increasing,and the difference was not statistically significant;the threonine and proline were decreasing,and the difference was not statistically significant.Comparing the DMBA-induced group 5 with taurine intervention and the DMBA-induced group 3,the methionine,isoleucine and tyrosine among the amino acids in the whole blood were decreasing,and the difference was statistically significant;while the rest amino acids were decreasing,and the difference was not statistically significant.2.Through analysis and identification,there were 5 kinds of differential metabolite in group 3 of DMBA-induced rats by comparing to group 1,which was mainly related to amino acid metabolism and glucose metabolism.By comparing group 5 of taurine-treated DMBA-induced rats and normal control group 1,23 kinds of metabolite had changed,involving the metabolic pathways of energy,glucose,amino acid and nucleic acid.3.By comparing group 3 of DMBA-induced rats and normal control group 1,the expression of Igf1 r and Pten gene in breast cancer group decreased,while the expression of Igf1 gene increased,the difference hereof was statistically significant;the expression of Akt1 & HK2 gene,Myc gene and HIF-1a gene decreased,and the difference was not statistically significant.By comparing group 5 of taurine-treated DMBA-induced rats and group 3 of DMBA-induced rats,the expression of Peten gene and Igf1 r gene increased,while that of Igf1 gene decreased,the difference hereof was statistically significant;the expression of Akt1,Myc,Hk2 and HIF-1a gene decreased,and the difference was not statistically significant.4.Rats have similar intestinal microflora with normal human.Rat intestinal microflora is mainly Firmicutes,followed by Bacteroides,and then by Proteobacteria,Actinobacteria and Mollicutes.We found in the experiment that the intestinal microflora of Group 3 of DMBA-induced rats changed,and six kinds of bacteria in Firmicutes were different from those of normal rats.Comparing Group 5 of taurine-treated DMBA-induced rats with Group 3 of DMBA-induced rats,12 kinds of bacteria from Firmicutes,Proteobacteria and Actinobacteria changed.?.Conclusion1.Taurine inhibits DMBA-induced breast cancer of rats significantly.High-fat diet promotes the molding of DMBA-induced breast cancer model.Amino acid in the body of breast cancer rats and taurine-treated breast cancer rats change.2.The metabolism in the body of taurine-treated breast cancer rats has changed,and metabolomics provides a clue for further illustrating the mechanism of taurine intervention for breast cancer.3.The taurine intervention for breast cancer of rats is embodied in increasing the expression of PTEN and Igf1 r gene,and decreasing the expression of Igf1 gene.The pathogenesis of breast cancer in rats may be associated with the decreased expression of PTEN gene and Igf1 r gene and the increased expression of Igf1 gene.4.Intestinal microflora of breast cancer rats has changed.One mechanism of taurine intervention for breast cancer of rats may be change in the composition of their intestinal microflora. |
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