Metal Ions/Nucleotide Coordinated Nanoparticles Comprehensively Suppress Tumor By Synergizing Ferroptosis With Energy Metabolic Interference

BackgroundCancer,also known as malignant tumor,is a progressive malignant disease.It begins with abnormal growth of cancer cells,then erodes normal tissues and can metastasize to other parts of the body,even is able to seriously endanger human life and health.From the perspective of treatment,traditional cancer treatments include surgery,chemotherapy,radiotherapy and so on.Chemotherapy or radiotherapy often induce apoptosis of tumor cells,but long-term treatment has a trend towards multidrug resistance in patients and leads to treatment failure.Therefore,it is particularly important to explore new tumor treatment methods.Ferroptosis is a new type of programmed cell death different from apoptosis,which is expected to improve tumor drug resistance caused by chemotherapy or radiotherapy,and has gradually become a new treatment of cancer.Ferroptosis is marked by reactive oxygen species（ROS）induced lipid peroxidation,which programs cell death.However,it has been suggested that the vigorous energy metabolism in tumor cells can help cells resist oxidative damage,thus reducing the role of ferroptosis in tumor therapy.Therefore,whether inhibition of energy metabolism can enhance the anti-tumor effect of ferroptosis is a scientific problem worthy of further study and exploration.In recent years,the construction of novel nanozymes based on coordination bonds between metal ligands has attracted extensive attention in the field of nanomedicine.This build way from reference to natural enzymes of metal structure and the characteristics of catalytic,metal ion and ligand molecules through the weak interaction between each other assemble into highly ordered nanostructures,and then at the molecular level simulation of natural enzyme active site features such as shape,size and its microenvironment,are expected to get with the natural enzymes are very similar metal biomimetic nanometer enzymes.Therefore,the nanozyme constructed based on Fe2+ is worthy of further exploration for tumor therapy by inducing ferroptosis in tumor cells.Based on the above research background,this paper constructed two nanozymes based on metal coordination.Fe2+/Guanine nucleotide（GMP）/polydopamine（PDA）nanozyme（FeGPNPs）and Fe2+/glyceraldehyde-3-phosphate dehydrogenase（GAPDH）siRNA（GAPDH siRNA）/polydopamine（PDA）nanozyme（FesiRNAPNPs）,In order to study the therapeutic effect of ferroptosis and energy metabolism interference in tumor,we hope to provide new methods and ideas for the treatment of tumors through the development of the research work in this paper.Purpose（1）Based on the structural characteristics of natural metal enzymes,the self-assembled nanocrase was constructed by the interaction between nucleotide and metal ions,and the effects of nucleotide structure,system composition and environmental factors on the formation of nanocrase were revealed.（2）Based on the in-depth understanding of the catalytic properties of nanozymes,the application of ferroptosis induced by nanozymes in anti-tumor were explored,and the effect of ferroptosis synergistic with energy metabolism interference on tumor therapy was evaluated.MethodsChapter 1:Study on the anti-tumor activity of FeGPNPs and its mechanismIn this chapter,FeGPNPs is prepared by the coordination between Fe2+ and nucleotide.Firstly,the morphology and size of FeGPNPs were characterized by transmission electron microscope（TEM）,scanning electron microscope（SEM）and dynamic light scattering spectrometer（DLS）.The structure and composition of the materials were analyzed by X-ray photoelectron spectroscopy（XPS）and high resolution transmission electron microscopy（HR-TEM）.After the basic structure and properties of FeGPNPs were clarified,the catalytic activity of FeGPNPs was investigated,and the ability and mechanism of FeGPNPs-induced ferroptosis were studied by MTT,Western blotting and laser confocal scanning microscopy（CLSM）.Finally,a tumor-bearing mouse model was constructed to evaluate the antitumor effect of FeGPNPs.Chapter 2:Study on the anti-tumor activity of FesiRNAPNPs and its mechanismOn the premise that FeGPNPs can induce ferroptosis,in this chapter,nucleotide derivative GAPDH siRNA was used instead of GMP to prepare FesiRNAPNPs.Firstly,the morphology and catalytic activity of FesiRNAPNPs were investigated by transmission electron microscopy（TEM）and color reaction.Secondly,MTT,Western blotting and laser confocal scanning microscopy（CLSM）were used to explore the ability and mechanism of ferroptosis synergistic energy metabolism induced by FesiRNAPNPs.Finally,a tumor-bearing mouse model was constructed to evaluate the antitumor effect of FeGPNPs.ResultChapter 1:The FeGPNPs prepared in this chapter has an obvious core-shell structure with a particle size about 100 nm.Enzymatic analysis showed that FeGPNPs had pHdependent peroxidase activity.In addition,Fe2+ released by FeGPNPs in tumor cells can induce Fenton reaction,leading to lipid peroxidation in tumor cells and downregulation of intracellular glutathione peroxidase 4（GPX4）expression,thereby inducing ferroptosis.Animal experiments have also proved that FeGPNPs has significant anti-tumor effect and high biosafety.Chapter 2:FesiRNAPNPs prepared in this chapter has a core-shell structure similar to FeGPNPs.Enzymatic analysis showed that FesiRNAPNPs also had pH-dependent peroxidase activity.Cell experiments showed that FesiRNAPNPs induced ferroptosis by releasing Fe2+on the one hand.On the other hand,the release of GAPDH siRNA can inhibit glycolysis and interfere with tumor energy metabolism,thus enhancing the effect of ferroptosis.Animal experiments also confirmed that FesiRNAPNPs had better antitumor effect than FeGPNPs.