Study On The Antibreast Cancer Activity And Mechanism Of Poria Cocos

Breast cancer is the most common cancer in women worldwide,which is the most significant threat to female health.Although chemotherapy is an efficent way to improve the survival rate of the patients,it may induce gastrointestinal reactions and severe damage to the liver and kidney to the patient.How to significanlty improve the survival of breast cancer patients while maximizing quality of life is an urgent problem to be solved at present during the breast cancer treatment.Poria cocos?P.cocos?is a natural plant used both as food and medicine for its high nourishing value.P.cocos has been reported to cure intestinal diarrhea and decrease the harmful on the spleen and stomach in human.It also has been reported that P.cocos could protect the liver from damage.Therefore,it may make us to speculate P.cocos could be used in the breast cancer treatment to reduce the toxicity and side effects on the liver and kidney for the patients.P.cocos,also as a kind of anti-cancer drug,has a long history in the treatment and recuperation of mammary gland hyperplasia and breast cancer in the field of Chinese traditional medicine,either as a single drug or in combination with other herbs.Although P.cocos has been reported to inhibit the proliferation and invasion of various cancer cells through disruppting the cell cycle or increasing the ration of Bax/Bcl-2 in cancer cells,the anti-breast cancer mechanism,the main active substances,the potential harmful side effects in vivo and its regulation of intestinal homeostasis have not yet been reported.In oder to clarify those questions,we start this research.Firstly,the effect of different extracts of P.cocos on the proliferation,cell cycle and apoptosis of breast cancer cells were evaluated in vitro.Then,the in vivo anti-breast cancer efficacy were further evaluated in BALB/c nude mice.Next,toxic side effects of ethanol extract of P.cocos?PC?in the mice and the intestinal barrier and intestinal flora in mice from each group were studied.Lastly,the key anti-cancer active components from P.cocos were separated,purified and obtained through the chromatographic column combined with preparative high performance liquid chromatography technology.The potental mechanism of the anticancer of P.cocos on breast cancer was also studied then.The main results of this study are as follows:1.Firstly,PC can significantly inhibit the proliferation of MDA-MB-231 and MCF-7 cells by inducing cell apoptosis and cell cycle arrested at G₀/G₁ phase in a time-and dose-dependent manner.The in vivo experiment revealed that PC could significantly inhibit the tumor development and decrease the final mean tumor weight of the mice.H&E staining and immunohistochemical staining of tumor tissue revealed that the structure and cell morphology of tumor tissues were significantly changed in PC-treated group as compared with the model group.Furthermore,results from TUNEL assay and immunohistochemistry analysis both demonstrated that PC could inhibit tumor development and promote the cell's apoptosis in the tumor tissue.2.Secondly,compared to the model group and the positive group treated with cisplatin,PC showed less side effects on the function of the vital organs and the muscle strength of the mice,indicating that PC could be more safe in the cancer treatment.PC prominently remitted the histologic damage in the tumor-bearing mice through enhancing the expression of TJ proteins and decreasing the levels of DAO,D-LA and endotoxin via upregulating the expression of phosphorylated ERK1/2 and p38 MAPK.Furthermore,PC increased the diversity of the intestinal microbiota and strikingly changed the structure and composition of the gut microbiota in the mice by increasing the beneficial bacteria Lactobacillus,Bifidobacterium,and decreasing the sulfate-reducing bacteria Desulfovibrio and inflammatory associated bacteria Mucispirillum,S24-7 and Staphylococcus.Moreover,PICRUSt analysis and the putrescine detection indicated that PC might be involved in the putrescine metabolism in the mice.3.Lastly,three compounds:3-O-acetyl-16-hydroxytrametenolic acid?D2-1?,dehydropachymic acid?D2-2?,and pachymic acid?D2-3?were finally obtained through chromatography.Pachymic acid?PA?,identified as the most active compound,which induced the significant cytotoxicity on breast cancer cells MDA-MB-231 as compared with other two compounds and was not active against the normal breast epithelium cells MCF-10A.Two key chemical bones existing in PA that is C₉-side-chain containing a 24-methylene group at C-17and unsaturated ethylenic bond at C-8,were speculated to help enhance the cell toxicity to breast cancer cells.The expression of cell cycle-associated cyclin D1,cyclin E,CDK2,and CDK4 were downregulated,while p53 and p21 expression were upregulated following the PA treatment.In addition,PA downregulated the apoptotic regulator Bcl-2,increased the expression of pro-apoptotic protein Bax,and promoted the release of cytochrome c and the activation of cleaved caspase-3,-9 and caspase-8 via mitochondria-mediated and death receptor-mediated signaling pathways.The main active substances and the anti-breast cancer mechanism were clarified in this paper.Addtionally,this study provided the first report to show that P.cocos could maintain the intestinal homeostasis of tumor-bearing mice by repairing intestinal barrier damage and improving the structure of intestinal microbiome.All those results indicated that Poria cocos may be a promise material that could be developed as an efficy agent for breast cancer treatment.These findings may provide the theoretical fundamental amd test basis for further exploitation of functional food from P.cocos or support the application of P.cocos in breast cancer treatment.