Mitochondrial Targeting Pt(Ⅳ) Complexs Based On Exosomal Inhibition And Glutathione Depletion For Overcoming Drug Resistance

Platinum-based drugs are the most widely used in clinical therapy and play an important role in cancer chemotherapy.However,their clinical success is limited due to severe side effects and resistance to the treatment.Therefore,the development of Platinum-based drugs with less toxic side effects and the ability to reverse drug resistance has become one of the hot spots in the research field.Pt(Ⅳ)prodrugs are Six-coordinate octahedral complexs,the axial ligands can be further modified by different molecules(such as enhanced lipid solubility,targeted and synergistic sensitization).The prodrugs are less lethal to tumor cells and only after being activated by the reductant substance can obtain cytotoxicity.Thus,compared with Pt(Ⅱ)complexes,Pt(Ⅳ)prodrugs provide a good way to reduce side effects.DNA damage repair,the secretion of exosomes,and the detoxification of thiol molecules(such as glutathione and metallothionein)have been recognized as the important mechanism for the development of resistance to platinum drugs.Platinum(Ⅳ)prodrugs still can’t overcome the multidrug resistance(MDR).Therefore,the search for therapeutic targets other than nuclear DNA,inhibiting the secretion of exosomes,and reducing the level of thiol moleculesare expected to overcome the resistance of traditional Platinum-based drugs.Among the endogenous thiol molecules,glutathione can undergo Michael addition with electrophilic conjugate system and participate in the redox process.On this basis,In order to solve the problems of resistance to platinum drugs caused by secretion of exosomes,detoxification of mercaptans and self-repair of nDNA,Cisplatin,pyridine(PY),sulfafurazole(SFX),4-dimethylaminopyridine(DMAP)and maleic anhydride as raw materials,using organic reactions such as substitution reaction and oxidation reaction to synthesize a mitochondrial targeting Pt(Ⅳ)complex(Pt PY-SFX)based on exosome inhibition and mitochondrial targeted Pt(Ⅳ)complexes(PtPY-COOH and PtDMAP-COOH)based on glutathione depletion;the structure of complexs were characterized by NMR and HRMS;the stability in serum or different pH conditions and the lipid-water partition coefficient were analyzed by Ultraviolet-Visible Spectrophotometry;the drug release mechanism was determined by HRMS;Using cisplatin-resistant A549 R and MDA-MB-231 cells as models,the cell viability was determined by MTT assay;the effects of complexes on mitochondrial membrane potential were investigated by fluorescence microscope;ATP and GSH levels in tumor cells were investigated by spectrophotometry;the effect of PtPY-SFX on cell migration was explored by cell scratch test.The results show that complexs have good stability in serum and different pH conditions;the lipid-water partition coefficient is between-1～2,the cytotoxicity of complexsare time-dependent;complexs can affect the mitochondrial membrane potential and reduce the intracellular ATP and GSH content;PtPY-SFX can effectively inhibit the migration of MDA-MB-231 cells.Complexs provide a new idea for the treatment of drug-resistant tumors.