Study On Inhibitory Effect And Mechanism Of Nano-?-tricalcium Phosphate On Hepatocarcinoma Cells

China ranks first in the world for new cases of cancer which is still an imminent problem that has not been satisfactorily solved.Researches have indicated that hydroxyapatite nanoparticle?HA?has a certain anti-cancer activity and can inhibit many kinds of cancer cells.Moreover,the degradation of nano-?-tricalcium phosphate?nano-?-TCP?is better than that of HA,but it's still not clear that nano-?-TCP will be used in cancer treatment.Here,targeting the difficult problems of treatment in malignant tumors and based on the inhibitory effect of HA nanoparticle on various cancer cells,the inhibitory effect and mechanism of nano-?-TCP on hepatocarcinoma cells?HepG2?were investigated in vitro and in vivo,providing valuable reference data to guide the design of nano-?-TCP-based anticancer drug carrier and therapeutic systems in the future.Nano-?-TCP was synthesized using ethanol-water system and characterized by X-ray diffraction?XRD?,Fourier transform infrared spectroscopy?FTIR?,Malvern laser particle sizer and Field-emission transmission electron microscopy?TEM?.In addition,MTT assay was used to investigate the cytocompatibility of nano-?-TCP with different concentrations in vitro.The results showed that?-TCP nanoparticles were successfully prepared and the average particle size was 72.7 nm.Cell viability of L929 cell is dependent on the concentration and time.There is a downward trend in cytocompatibility when nano-?-TCP has the higher concentration and the longer incubation time.The effects of nano-?-TCP on cell viability,cell uptake,mitochondrial potential,intracellular oxidative stress?ROS?,cell cycle and apoptosis were also investigated with HepG2 cells as the model cell line and human hepatocyte cells?L-02?as the control.The results showed that nano-?-TCP inhibited cell viability of both cell types and inhibition on HepG2 cells seemed more obvious,the effect was dependent on incubation time and the concentration of nano-?-TCP.The anticancer mechanism is following:?1?Nano-?-TCP was internalized into tumor cells by nonspecific endocytosis and rapidly degraded,resulting in a significant increase of intracellular Ca²⁺and PO₄^3-ions;?2?Nano-?-TCP also promoted the production of ROS and decreased mitochondrial potential,activated extrinsic and intrinsic apoptosis signaling pathways,leading to cancer cell apoptosis;?3?Nano-?-TCP blocked liver cancer cell cycle in G0/G1 phase and reduced the expression of related cyclins,such as CyclinD1,CDK2,CyclinE and?-catenin.Nude mice?BALB/c nu/nu?were used as animal models,the side effects of nano-?-TCP on nude mice were investigated.Then intratumoral injection of nano-?-TCP was performed on the xenograft liver cancer model to explore the inhibitory effect and mechanism of nano-?-TCP on liver tumors.The results showed that nano-?-TCP at 40 mg/kg had no obvious side effects on nude mice,but a certain inhibition on liver tumor in vivo.Nano-?-TCP promoted the expression of caspase-3,caspase-8 and caspase-9,thereby promoting subsequent apoptotic signaling and cell apoptosis.This mechanism is consistent with that nano-?-TCP could promote apoptosis in hepatocellular carcinoma cells in vitro.