Objective To modify YC-1,an inhibitor of hypoxia-inducible factor-1α(HIF-1α)into nanoparticles and explore its effect on reversing chemoresistance of colorectal cancer cells.Methods Nano-inhibitor mPEG350-YC-1(MYC-1)was prepared by the carboxyl condensation reaction of the active functional group hydroxyl(-OH)in the YC-1 molecule with methoxy polyethylene glycol carboxylic acid,and was verified by 1H nuclear magnetic resonance(1H-NMR).Its morphology was analyzed by transmission electron microscope(TEM),and its particle size distribution was analyzed by dynamic light scattering(DLS).By interacting FITC-labeled MYC-1(FYC-1)with HCT15 cells,the uptake ability of FYC-1 by the cells was observed using laser confocal microscopy.The cytotoxicity of MYC-1 was measured with CCK-8 assay.The sensitization effect of MYC-1 on the chemotherapy drug 5-Fu was detected through toxicity tests of resistant HCT15 cells(resistant HCT15,R-HCT15)and live/dead cell staining.The mechanism of MYC-1 reversing drug resistance was determined with immunofluorescence staining of HIF-1α and western blotting.Finally,a subcutaneous transplanted tumor model of R-HCT15 cells was constructed.The tumor bearing mice were randomly divided into PBS,5-Fu,MYC-1,and MYF groups,with 3 mice in each group.The tumor volume and weight were observed after treatment in each group to evaluate the ability of MYC-1 to reverse 5-Fu resistance in colorectal cancer.Results The nano-inhibitor MYC-1 was successfully prepared.TEM and DLS showed that MYC-1 could self-assemble into nanoparticles with a diameter of approximately 19.96±2.97 nm in aqueous solution.FYC-1 was also successfully prepared.When FYC-1 was interacted with HCT15 cells,FYC-1 could be better taken up by the cells,indicating that the amphiphilic MYC-1 could be better endocytosed into the cells to exert its function.When MYC-1 and 5-Fu acted in combination in colon cancer R-HCT15 cells,the resistance index(RI)was decreased from 7.99 to 1.55,and the relative reversal rate(RRR)of RI was 80.6%.Live(green)/dead(red)cell staining revealed that MYC-1 increased the toxicity of 5-Fu to R-HCT15 cells.Immunofluorescence staining(P<0.01)and Western blotting indicated that MYC-1 effectively inhibited the intracellular expression of HIF-1α.The combined action of MYC-1 and 5-Fu on mice with R-HCT15 subcutaneous transplanted tumors had the best therapeutic effect when compared with PBS(P<0.001),5-Fu(P<0.01),and MYC-1(P<0.01).Immunofluorescence staining of HIF-1α in tumor tissues displayed that the expression of HIF-1α was decreased in the MYC-1 and MYF groups.HE staining showed that there was no obvious damage to the important organs in each treatment group.Conclusion Nano-inhibitor MYC-1 can reverse the drug resistance of colorectal cancer to 5-Fu chemotherapy by reducing the expression of HIF-1α protein in colorectal cancer cells,thereby effectively improving the therapeutic effect of 5-Fu.

Objective To prepare FLIVIGSII peptide(FI peptide)and investigate its physicochemical properties and hemostatic effect in vivo and in vitro.Methods The self-assembling peptide-based hydrogels were prepared by the FI peptide mixed with water.After gross observation for the hydrogel state of the FI peptide,scanning electron microscopy(SEM)and transmission electron microscopy(TEM)were used for its microstructure,and dynamic light scattering(DLS)was performed for its size.The hemostatic effect of FI peptide after being mixed with blood samples treated with 3.8％sodium citrate was observed,and the microstructure of the blood clot was observed with SEM.CCK-8 assay and hemolysis assay were performed to verify its biocompatibility.After a rat model of hepatic parenchymal perforation and hemorrhage was established,15 female SD rats(6～8 weeks old,weighing 150 g)were randomly divided into control group,FI peptide group and fibrin sealant group.The hemostatic effect of FI peptide and prognosis was observed and analyzed after treatment in each group,and the hemostatic mechanism was also investigated.Results FI peptides were successfully prepared,and it could rapidly self-assemble into a nanofiber network hydrogel in water,and further cause formation of blood clots.SEM showed that FI peptides self-assembled to form fibrous hydrogels after mixing with water.TEM results verified that the FI peptide formed into nanofibers in a diameter of 13.70±2.31 nm after gelatinization in water,and DLS results verified that the FI peptide formed polydisperse and multi-size nanofibers in water(in a range of 148.2～208.0 nm or 575.0～807.0 nm).The fibrous hydrogel formed by the FI peptide mixed with the blood could envelop the red blood cells,thus form a physical hemostatic barrier to achieve blood clotting in seconds.FI peptide hydrogel had no cytotoxicity to normal hepatocytes(L-O2 cells)and did not cause hemolysis of red blood cells.In in vivo experiment,FI peptide quickly formed nanofiber hydrogel when in contact with blood,thus formed physical hemostasis barrier to achieve hemostasis within a few seconds(hemostasis time＜5 s).Conclusion The FI peptide exhibits a rapid and efficient hemostatic effect,indicating a promising clinical application in the hemostasia of hepatic parenchymal traumatic hemorrhage.