The Study Of Tea Flower-Derived Nanovesicles In The Treatment Of Breast Cancer

According to the latest epidemiological statistics,the incidence of breast cancer among female cancer population is the highest and rising year by year,which has seriously threatened women’s health.At present,chemotherapy is the main means of clinical treatment for breast cancer,but the commonly used chemotherapeutic drugs(such as paclitaxel)can not completely remove breast cancer cells,accompanied by serious toxicity and side effects.In recent years,with the development of nanotechnology in the field of biomedicine,many nanodrugs have been used in the clinical treatment of breast cancer.Liposomes,as a carrier with the advantages of low toxicity,high efficiency and good biological safety,have become one of the earliest nano-drug carriers used in clinical practice.However,liposomes are still faced with the problems of limited synthesis scale,unavoidable use of toxic solvents,and difficult to mass production.In recent years,it has been found that plants contain many natural lipid nanovesicles,which not only have good biological safety,but also contain small natural organic molecules which can effectively treat inflammation,cancer and other diseases.Because of its wide source,low cost and remarkable curative effect,the nanovesicles have very good clinical application value.In view of this,many lipid nanovesicles(TFNPs)were extracted from tea flowers by various centrifugation methods.The detection showed that TFNPs contained abundant catechins and flavonoids.A series of in vivo and in vitro experiments showed that TFNPs had good anti-tumor activity.The main research contents and conclusions of this paper are divided into the following four parts:The first part is the morphological characterization of TFNPs.The particle size and surface potential of TFNPs were analyzed by dynamic light scattering technique.The morphology of TFNPs was observed by transmission electron microscopy.Conclusions: TFNPs were spherical in shape,with a diameter of 131.6 nm and a surface potential of-7.94 mV,and had good stability in gastrointestinal and humoral simulated fluids.The second part is in vitro pharmacodynamics evaluation of TFNPs.MTT assay was used to detect the inhibitory effect of TFNPs on the proliferation of various cancer cells(MCF-7,4T1,A549 and Hela).Annexin V-FITC/PI staining was used to detect the apoptotic ability of TFNPs.The cell cycle status of tumor cells was detected by PI staining.The ability of inhibit the infiltration and migration of tumor cells was tested by cell scratch and transwell assay.Flow cytometry and confocal microscopy were used to quantitatively and qualitatively analyze the changes of reactive oxygen species and nitrogen clusters in tumor cells after TFNPs treatment.Finally,TFNPs were labeled with DiO probe to detect the ability of TFNPs to be swallowed by tumor cells.Conclusions: TFNPs showed the greatest inhibitory effect on the proliferation of MCF-7 cells.IC50 value was 0.1 ug/mL at 72 h.TFNPs could significantly induce breast cancer cells apoptosis,decrease mitochondrial membrane potential,increase cleaved-Caspase 3 expression and decrease Bcl-2 expression.TFNPs can block MCF-7 cells in G2/M phase and 4T1 cells in S phase,thus inhibiting cell proliferation.TFNPs significantly inhibited the infiltration and migration of MCF-7 and 4T1.In addition,TFNPs can effectively promote the expression of reactive oxygen species and nitrogen clusters in both cells.Cell phagocytosis experiments showed that TFNPs were significantly engulfed by cells and widely distributed in the cytoplasm.The third part is pharmacodynamic evaluation of TFNPs in vivo.MCF-7 cells and 4T1 cells were used to construct subcutaneous breast cancer model and lung metastasis model respectively.Subcutaneous injection and oral administration were used to give TFNPs.In the experiment of subcutaneous breast cancer,the ability of TFNPs to inhibit the proliferation of subcutaneous breast cancer was comprehensively analyzed by analyzing the weight of mice,the tumors volume,the tumors weight and tissue staining.In the experiment of lung metastasis of breast cancer,the ability of TFNPs to inhibit lung metastasis of breast cancer was comprehensively analyzed by analyzing the weight of mice,the number of lung metastases and tissue staining.Conclusions: In the subcutaneous breast cancer experiment,intravenous injection and oral administration of high dose of TFNPs could effectively inhibit the growth of tumors,the inhibition rates were 75.8% and 65.1% respectively,showing good therapeutic effect.In the lung metastasis experiment of breast cancer,the same intravenous injection and oral high dose of TFNPs can effectively inhibit the metastasis of breast cancer cells in lung tissue,thus effectively prolong the survival time of mice with breast cancer,and there is no significant statistical difference between the two groups.The fourth part is in vivo and in vitro safety evaluation of TFNPs.Firstly,in vitro hemolysis experiment proved that TFNPs did not cause serious hemolysis.Then TFNPs were given to healthy mice by intravenous injection and oral administration for several times.The in vivo safety of TFNPs was evaluated comprehensively in terms of immune factors,complements,hepatorenal toxicity and tissue staining.Conclusions: Intravenous injection of TFNPs could cause abnormal increase in the expression of complement C3 and alanine aminotransferase in plasma.Through the analysis of organs sections,it was speculated that intravenous injection of TFNPs would cause serious toxic and side effects on liver.The indexes of mice in the oral TFNPs group were normal,and there was no significant difference between the oral TFNPs group and the normal group.In conclusion,this project not only opens up a new way for the practical application of Camellia sinensis,but also opens up a new research idea for the clinical treatment of breast cancer.In a word,the development of this project has great practical value and clinical transformation significance.