Effect Of Cur@Hb Nanoparticles On The Radiosensitivity Of Hypoxic Hepatocellular Carcinoma Cells And Its Mechanism

Objective:To investigate the effect and mechanism of Cur@Hb(Curcumin@Hemoglobin)nanoparticles on the cell phenotype,such as proliferation,cell cycle,apoptosis,migration,and angiogenesis,and radiosensitivity of hypoxic hepatocellular carcinoma cells.Methods:Cur@Hb nanoparticles were designed and synthesized,and characterized by transmission electron microscopy(TEM),dynamic light scattering(DLS),ultraviolet spectrometer,and infrared spectrometer.DPBF was used to detect the generation of ROS and confocal microscopy was used to characterize the distribution of Cur@Hb in cells.CCK-8 assay was used to detect cytotoxicity and cell proliferation.The cell cycle,apoptosis,and ROS content were detected by flow cytometry.Wound healing assay was used to detect cell migration.The vasculogenic mimicry experiment was used to detect the formation of tube-like structures of SMMC7721 cells in vitro,and Western blot was used to detect the changes in the expression of EMT-related proteins.In normoxic and hypoxic conditions,radiosensitivity of hepatocellular carcinoma cells were measured by cloning formation assay.yH2AX immunofluorescence staining and comet assay were used to detect DNA damage repair ability.Macrophage polarization was detected by flow cytometry.Tumor-inhibiting effect of Cur@Hb nanoparticles on hepatocellular carcinoma was detected in nude mouse xenograft mode.Results:Incubation of 250 ?g/mL Cur@Hb in normoxia or hypoxia(1%O2)for 24 h can significantly inhibit the proliferation and migration of SMMC7721 cells,and promote apoptosis.Cur@Hb combined with 4 Gy X-ray irradiation caused G2/M phase arrest of SMMC7721 cells.In addition,Cur@Hb nanoparticles can significantly inhibit the generation of vascular tube-like structures and the expression of EMT-related protein VE-cadherin,twist1 and MMP2.Under normoxic culture,Cur@Hb nanoparticles can promote the polarization of macrophages from M2 to M1,and effectively increase ROS production.Cur@Hb nanoparticles significantly enhanced the radiosensitivity of normoxic and hypoxic SMMC7721,with radiosensitization ratios of approximately 1.237 and 1.510,respectively.Cur@Hb nanoparticles significantly increased the x-ray-induced ?H2AX foci and percent of DNA tail of normoxic or hypoxic SMMC7721 cells.Cur@Hb nanoparticles can increase the concentration of oxygenated hemoglobin in nude mice xenografts and significantly enhance the effect of radiotherapy.Conclusion:Cur@Hb nanoparticles can significantly improve the radiosensitivity of hypoxic hepatocellular carcinoma SMMC7721 cells and enhance the radiotherapy effect on human hepatoma xenografts in nude mice.The mechanism of its radiosensitizing effect may be related to its inhibition of hepatoma cell proliferation,DNA damage repair and angiogenesis,and promotion of cell apoptosis.Cur@Hb nanoparticles have important potential as radiosensitizers for hypoxic tumors,and deserve further study.