Study On The Inhibitory Effects Of Ginkgo Biloba Polysaccharides On Mouse Breast Cancer 4T1 Cells And The Expression Of GLUT1

Background: Breast cancer is the common high incidence and high mortality malignancy in women.At present,the treatment of breast cancer are mainly surgical resection,radiotherapy and chemotherapy.However,due to the strong side effects of chemotherapy and radiotherapy,and the poor prognosis of cancer patients,clinical treatment of breast cancer is not satisfactory.Therefore,the search for and development of anti-tumor drugs with high safety and low side effects have become the key to cancer treatment.Ginkgo biloba polysaccharides are active substance extracted from Ginkgo biloba leaves,fruits and outer seed coats.They have been confirmed that play the key role in regulating immunity,inhibiting tumor proliferation,anti-allergy,hypolipidemic,adjuvant radiotherapy and chemotherapy.A large number of studies have shown that inhibition of tumor cell proliferation,invasion and metastasis are the key to clinical cancer treatment.With the continuous deepening of the research on the molecular mechanism of tumor cell energy metabolism,it is a new idea to target the treatment of breast cancer through the development of small-molecule breast cancer inhibitors to block the glycolysis pathway of tumor cells.2-deoxy-D-glucose(2-DG)is a synthetic hexokinase inhibitor that can competitively inhibit glucose uptake in cancer cells and block glycolysis pathways.Clinical studies have shown that although 2-DG has a good effect of inhibiting the proliferation of cancer cells,it is difficult to apply to clinical treatment due to its strong toxicity,so the current research focuses on 2-DG and adriamycin,paclitaxel,etc.Other anti-cancer drugs have been used in combination and have achieved certain results.Objective: To investigate the effects of Ginkgo biloba polysaccharides and 2-DG either alone or in combination on the proliferation and apoptosis of mouse breast cancer 4T1 cells and the related mechanisms.Methods: 4T1 cells in logarithmic growth phase are treated with different concentrations of Ginkgo biloba polysaccharides and combine use of 2-DG.MTT assay and trypan blue staining are used to detect cell proliferation,inhibitory and cytotoxic effects;DAPI nuclear staining assay are used to detected 4T1 cell apoptosis;RT-PCR are used to detected 4T1 cell glucose transporter family effects of m RNA expression;Western blot are used to examine glucose transporter-1effect of protein expression.Results: The results of MTT assay show that Ginkgo biloba leave,exocarp polysaccharides and 2-DG inhibit the proliferation of 4T1 cells in a dose-dependent manner,and the halfinhibitory concentrations are 196.423 mg·L-1,484.231 mg·L-1and 389.265 mg·L-1,respectively.The maximum inhibitory rate are(69.24±2.14)%,(59.08±3.56)% and(72.36±3.23)%,compare with the control group respectively(P<0.01).400 mg·L-12-DG combine use of 800 mg·L-1 Ginkgo biloba seed polysaccharide,200 mg·L-1 Ginkgo biloba leaf polysaccharide and 500 mg·L-1 Ginkgo biloba exocarp polysaccharide,the inhibition rates of cell proliferation are(43.26±1.22)%,(59.32±1.51)% and(56.62±2.36)%,compare with the control group respectively(P<0.01).The results of trypan blue exclusion assay show that with the increase of the dose of Ginkgo biloba polysaccharides and 2-DG,the cell viability significant decrease and toxicity are significantly enhanced.When the Ginkgo biloba leaf,exocarp polysaccharides and 2-DG dose reached 800 mg·L-1,the cell viability are(12.29± 0.34)%,(14.58±0.59)%,and(39.85±2.36)%,compare with the control group respectively(P<0.01).400mg·L-12-DG combine use of 800mg·L-1 Ginkgo biloba seed polysaccharide,200mg·L-1 leaf polysaccharide and 500mg·L-1 exocarp polysaccharide and the cell survival rates are(81.24±2.21)%,(73.56±2.26)% and(78.52±3.21)%,compare with the control group respectively(P>0.05),suggesting that 2-DG combine with Ginkgo biloba polysaccharides do not enhance cytotoxicity;DAPI nuclear results staining show that use of Ginkgo biloba polysaccharides alone and in combination with 2-DG significantly induced apoptosis in 4T1 cells.RT-PCR results show that Ginkgo biloba polysaccharides and combine use of 2-DG can significantly reduce the expression of glucose transporter-1 m RNA.Western blot results show that Ginkgo biloba polysaccharides and combine use of 2-DG can significantly reduce the expression of glucose transporter 1 protein.Conclusion: Ginkgo biloba polysaccharides combined use of 2-DG can both inhibit 4T1 cell proliferation and induce cell apoptosis,and by regulating Glucose transporter-1 expression interfere with cell energy metabolism,which infers that the cell proliferation inhibitaion effects as well the apoptosis induction effects might be due to the regulation of Glucose transporter family expression.