Dual-Targeting Polymeric Nanocarriers To Deliver ROS-Responsive Prodrugs And Combat Multidrug Resistance

In the clinical treatment of tumor,most patients will show drug resistance,which will reduce the effect of chemotherapy,and small molecule chemotherapy drugs will bring corresponding side effects,which greatly limits the effect of tumor treatment.Nanomedicine have been widely used in tumor treatment.One of the great advantages of Nanomedicine is to effectively load hydrophobic drugs,release the drugs in tumor location triggered by tumor microenvironment.And modify the surface of nanoparticles with targeting moiety,which can improve the efficiency of nanoparticles in treatment.The targeting moieties are modified to the surface of the particles,which can enhance the drug uptake of tumor cells and deliver the drug to the corresponding organelles in the tumor cells.It can effectively improve the accumulation of drugs in tumor cells and play a therapeutic effect,thus eliminating the resistance of tumor cells to reverse the multidrug resistance.In this report,we proposed a dual target drug delivery system(DT-NP)for cancer cells and mitochondria.The azide terminal amphiphilic polymer was synthesized by RAFT polymerization with chain transfer reagent with azide group,in which hydrophobic block can release cinnamaldehyde in tumor microenvironment.The group which can target tumor cells and mitochondria were modified at the terminal of polymer.Prodrug BDOX was encapsulated into the nanoparticles by self-assembly.The release of cinnamaldehyde by DT-NP in the acid condition of the endosomes,which can effectively induce the production of ROS in cancer cells,especially in mitochondria.After nanoparticles entering mitochondria by targeting moiety,high-level ROS in mitochondria can activate BDOX in situ,release DOX which can be interaction with mitochondrial DNA and induces apoptosis.The main work of this paper is as follows:1.Preparation of responsive target polymers.Firstly,pH-responsive monomer was synthesized,and pH-responsive cinnamaldehyde precursor was prepared by aldol condensation reaction.Then,the reactive precursor was connected to double bond by acylation reaction,and the monomer CAMA was used for later polymerization.Then,the RAFT chain transfer reagent with an azide terminal was prepared.The azide propanol was obtained by the reaction of sodium azide and bromopropanol.The RAFT chain transfer reagent with an azide terminal was obtained by esterification between carboxyl RAFT chain transfer reagent and azithropropanol.Then,amphiphilic polymer was prepared,and the hydrophilic monomer OEGMA with good biocompatibility was selected for polymerization to obtain homopolymer N3-OEGMA.Then the homopolymer was polymerized as macromolecular chain transfer reagent and hydrophobic cinnamaldehyde monomer to obtain the amphiphilic block polymer N3-OEGMA-b-PCAMA.Then,the targeting moieties,FA and TPP,were connected to the terminal of the polymer by clicking chemistry to obtain the target polymers FA-OEGMA-b-PCAMA and TPP-OEGMA-b-PCAMA.2.The preparation of targeted particles and the ability to encapsulate prodrug.First,small molecular precursor was prepared.The antitumor drug DOX and benzoborate were used to get BDOX,which can response to ROS.Then,the precursor and target polymers were prepared by the method of nano precipitation.The particle size and dispersion were measured by dynamic light scattering(DLS),morphology was measured by TEM.The encapsulation efficiency of the prodrug was determined by fluorescence.In vitro the release of nanoparticles was measured under different stimulation,and the release ability of Cinnamaldehyde and DOX was tested.3.The tumor therapeutic ability and intracellular characterization of targeting particles.The therapeutic effect and mechanism of dual targeting particles on drug-resistant cells were studied.Firstly,in cytotoxicity test,MTT experiment was used to evaluate the therapeutic effect of particles.The nanoparticles with different concentrations of dual targeting,single targeting and no targeting group were incubated with MCF-7 and mcf-7/ADR.The results show that the particles can kill the cells effectively with the dual target effect.Even in the drug-resistant cells,the dual-targeting particles drug carrier still show better antitumor effect than free DOX.After the drug-resistant cells were incubated with dual-targeting and no-targeting particles,the target groups in the dual-targeting particles could be efficiently delivered to the cells and the prodrug BDOX was activated in the targeted organelle.The concentration of active oxygen and glutathione in the cells were tested.The dual-targeting particles can effectively improve the concentration of ROS in tumor cells,and effectively reduce the glutathione content in tumor,improve the oxidative stress in the cells and promote the death of tumor cells.