Biomedical Applications And Oxidative Damage Effects Of Novel Fe-based Nano-frameworks

In recent years,anti-tumor strategies based on reactive oxygen species(ROS)-induced oxidative damage has attracted widespread attention.Taking advantage of the weak acidity and high oxidative properties of tumors,resea rchers have combined nanoscience to construct tumor microenvironment-specific nano-agents for inducing oxidative damage in tumor cells,thereby achieving efficient tumor therapy.With the advancement of genomics and proteomics research,nucleic acid and pr otein oxidative damage biomarkers have been discovered,and the detection methods of these biomarkers have been established,which provide theoretical evidence for effective cancer therapy based on oxidative damage.Therefore,through precise analysis of ROS-induced oxidative damage markers,we can gain a deeper understanding of their biological functions and dynamic connection with the body.This can provide practical theoretical basis for the occurrence or development mechanism of tumors and discovery of drug targets,and promote clinical research on tumor therapy.To further understand the reaction mechanism of ROS,and oxidative stress-induced biomarkes affect physiological activities from subcellular to living levels.In this thesis,we took a novel Fe-based nanoframeworks-induced cancer therapy as the starting point,study the biological effects caused by oxidative damage at the in vivo and cellular levels.Next,we detected and analyzed oxidative damage markers and their related proteins from genomics and proteomics.Then,we investigated the important roles of oxidative damage DNA modifications and their binding proteins in epigenetic regulation and cell fate determination.The details of the study are as follows:In Chapter 2,the complex synthesis and difficulties in functional regulation of multifunctional nanomedicines blocked the feasibility of nano-based therapies.Inspired by ingenious natural coordination events,we presented a straightforward methodology to program the function of metal-molecule frameworks.Without the need of complicated ligand design and synthesis,facile function manipulation of frameworks at the molecular level,can be achieved by only introducing a function-switching module capable of coordinating with metal cores in well-defined nonfunctional/single-function frameworks.Such strategy can not only shield adverse solvent or large steric effects during framework manufacture or modification,but also endow the framework with multiple functionalities,including potent phototherm al conversion and enhanced Fenton catalysis,which provides a new conceptual idea for the preparation of multifunctional nanomedicines.In Chapter 3,oxidative damage induced apoptosis has become a hot topic in cancer therapy.In this chapter,we applied t he constructed DA-Fe-NFs to oxidative damage-induced synergistic tumor therapy in vivo.By the characteristics of tumor microenvironment,the photothermal effect induced by DA-Fe-NFs can accelerate the catalytic rate of Fenton reaction,generate highly cyt otoxic·OH in tumor xenograft model,achieved complete tumor ablation after laser irradiation.In addition,multifunctional integration through the introduction of function-switching module enables DA-Fe-NFs achieved multimodal noninvasive tumor imaging.T he good anti-cancer effect was observed at the cellular,tissue and in vivo levels,providing crucial theoretical value and potential clinical significance for developing of tumor therapeutics based on oxidative damage.In Chapter 4,to investigate the biological effects of oxidative damage at the cellular genomic level,we developed a rapid,simple and cost-effective biosensing method for the detection of 8-oxoguanine(8-oxo G).The oxidant K₂Ir Br₆ interacts with8-oxo G to produce biotinylated 8-oxo G in DNA,allowing for detecting.Without the complex sample preparation and expensive instruments,high sensitivity can be achieved by using only commercial reagents.Further,the method was available to detect of DNA glycosylases activity in vitro and in vivo.It was also successfully applied to the study of the biological effects induced by DA-Fe-NFs at the genomic,level of 8-oxo G in DNA was identified.Establishment of this highly applicable biosensing assay provides an effective protocol for studying 8-oxo G-related biological functions and the biological mechanisms of nanomedicines based on oxidative damage.In Chapter 5,an in-depth understanding of biological impact of oxidative DNA damage and their binding proteins in the organism can provide an important t heoretical basis for cancer therapy.To this end,using 8-oxo G bait ds DNA with high affinity biotin-tag as a probe,we quantitatively identified potential 8-oxo G binding proteins from HEK 293T protein samples by SILAC in combination with DNA pull-down assay.The identified potential 8-oxo G binding protein YBX1 was validated in vitro,and its biological effects during oxidative stress were preliminarily investigated.We hypothesize that YBX1 may act as a key signaling protein in the mechanism of oxidative stress,regulating the dual regulation process of mt DNA copy number.The results at the proteomic level will,to some extent,contribute to a deeper understanding of the mechanisms of cancer development and the principles of oxidative damage-mediated therapy.