Evaluating The Inhibition Of Disulfide Bond Paclitaxel Polymeric Micelle To Breast Tumor In Vitro And Vivo

Paclitaxel is widely used in first-line treatment of breast cancer,non-small cell lung cancer and other solid tumors.But paclitaxel has low solubility in water.So anhydrous ethanol and Cremophor EL must be used as the solvent.But it easily leads to severe allergic reactions and limits its clinical use.In order to overcome the poor water solubility and achieve tumor targeting release,many new formulations of paclitaxel came into being.Among them,reduction-responsive nano-paclitaxel polymers utilize the redox difference between tumor cells and normal cells or extra-and intra-cellular differences,it can theoretically achieve efficient tumor cell-triggered drug release and reduce drug leakage in blood circulation or normal cells,and reduce side effects.Objective: In this study,We selected a reduction-responsive paclitaxel polymers nano-preparation [P(PEGMEA)-co-P(PDPHEMA)-g-PTX] as research object.Its effect on breast cancer cell lines and animal models was evaluated by in vitro and in vivo experiments.We hope to provide the experimental basis for the clinical application of the new paclitaxel.Methods:(1)The disulfide bond paclitaxel was diluted with physiological saline into different concentration gradients and MCF-7 cells were treated with them.The cytotoxic effect on MCF-7 breast cancer cell was evaluated by MTT,after 24 h.The concentration inhibition rate curve was plotted and IC50 was set.The breast cancer cells(MCF-7,MDA-MB-231),human normal mammary epithelial cells(MCF-10A),human macrophage cells(U937)were separately set to control group,positive control group,drug administration group.The control group: copolymer,positive control group: paclitaxel,administration group: P(PEGMEA)-co-P(PDPHEMA)-g-PTX.Cell apoptosis were detected by MTT,after 24 h.Another culture a group of MDA-MB-231 cells with paclitaxel micelle,after 48 h,to detect cell apoptosis by flow cytometry.(2)MCF-7 breast cancer nude mice model was prepared.Select 18 tumor-bearing nude mice and randomly divided them into three groups(control group: copolymer,16mg/kg;positive control group: PTX,5mg/kg.administration group: disulfide bond paclitaxel formulation,16mg/kg).We measured the tumor size every 3days,we weighed the tumor at last and elevated tumor inhibition rate.We also took the blood conut and made the HE staining of Nude mice' heart,liver,spleen,lung,kidney and tumor.Three groups of nude mice were cultured in the same way,but the dosage was(polymer,5mg/kg;PTX,5mg/kg,disulfide bond paclitaxel formulation,5mg/kg).(3)The results were analyzed using statistical software SPSS 18.0,each set of data was given as mean± SD.Comparison between groups used ANOVA variance analysis and comparison between the two groups used t-test.The level of statistical significance was set as p< 0.05.Results:(1)In vitro experiment,MTT results showed,With increasing concentration of paclitaxel micelle,The inhibition of MCF-7 cell gradually strengthened,there was a very significant dose-effect relationship,the IC50 was 6.13?g/ml.The drug was administered at a concentration of 10?g/ml,Compared with the copolymer,cell inhibition rate of MCF-7 cells,MDA-MB-231 cells and normal human breast cells MCF-10 A was 52.4%,56.0%,22.4%(p<0.05).The viability of U937 cells can be promoted(24.3%).Compared with paclitaxel group(10?g/ml),there was no significant difference in the inhibitory rate of different cells.Disulfide bond paclitaxel and paclitaxel had the effect of inducing MDA-MB-231 cell apoptosis.(2)In vivo,Nude mice in copolymer group and disulfide paclitaxel group had a better state.The mental state of nude mice in paclitaxel group began to sluggish and their activities decreased after 2 weeks administration and two mice were dead.(1)In the same apparent drug concentration,tumor growth was inhibited in PTX group and disulfide paclitaxel group.The tumor size was 3590±877,4125± 792mm3,respectively.(2)In the same actual drug content,the tumor size of PTX group was 1936±399mm3 and disulfide paclitaxel group was 1637±371 mm3.PTX group and disulfide paclitaxel group had the same weight: 2.00±0.18 g.Inhibition rates of tumor both are 33.7%.Disulfide bonds paclitaxel had no significant effect on myelosuppression.HE staining showed: Necrotic area could be seen in tumor tissue.Heart,lung and kidney had no significant change.Liver and spleen could find a small amount of inflammatory cell infiltration.There was no significant difference in pathology between the disulfide bond paclitaxel group and the paclitaxel group on tumor tissue.Conclusion: The disulfide bond paclitaxel was water-soluble,it didn't need anhydrous ethanol or Cremophor EL as a solvent and eliminated allergic reactions.Disulfide bonds paclitaxel has a very significant inhibitory effect on breast cancer cell(MCF-7),the inhibitory effect was dose dependent.Disulfide bonds paclitaxel and PTX significantly inhibited the proliferation of breast cancer cells.Disulfide bonds paclitaxel and PTX could effectively improve the immunoenhancing effect of macrophage(U937)and induce apoptosis of MDA-MB-231 cells.In vivo,when the same antitumor effect was achieved with paclitaxel,the disulfide bonds paclitaxel had lower paclitaxel content.After reaching the optimum effective concentration,if we continued increasing the concentration of disulfide bonds paclitaxel,it cannot significantly improve the effect of anti-tumor.Its inhibitory effect was mainly focused on tumor tissue,with a smaller side impact.