| Osteosarcoma is one of the most common tumors in children and adolescents.It is extremely malignant and often leads to amputation and paralysis,which lead to a great harm to society and family.Since the introduction of chemotherapy into adjuvant surgery in the 1970s,the survival rate of patients has increased from less than 20%to about 60-70%.However,in the past 40 years the survival rate has not been significantly improved,and the treatment of osteosarcoma has entered a bottleneck period.With the progress and development of nanotechnology,much more anti-tumor technology based on nanomaterials have been developed rapidly.In these methods,based on the unique tumor microenvironment with high content of hydrogen peroxide and weak acidity,chemodynamic therapy(CDT)as a novel tumor treatment strategy can catalyzes excess hydrogen peroxide(H2O2)to generate highly toxic hydroxyl radical(·OH)through Fenton reaction.However,traditional iron-based Fenton catalyst has a low reaction rate in the weakly acidic environment of tumors.Hollow copper ferrite nanoparticles(HCF NPs)with dual catalytic system developed by our laboratory showed good Fenton catalytic activity in the weakly acidic environment.However,it is farm enough to rely only a single method for tumor treatment.Multimodal combination therapy can provide the possibility for efficient treatment of tumor.Photothermal therapy(PTT),chemotherapy and gene therapy are all effective strategies for tumor therapy.In this study,we constructed HCFP@PDA composite nanomaterials to load DOX and siHSFl for synergistic CDT/PTT/chemotherapy/gene therapy to achieve mild and effective treatment of osteosarcoma.In addition,since the chemotherapy drugs used in tumor treatment will lead to the low immunity,once infection occurs,the process of tumor treatment will be affected and even death,this paper also studied the anti-infection effect of HCFP NPs under the action of CDT/PTT.The main contents and conclusion of this study are as follows:(1)HCFP@DOX NPs for synergistic CDT/PTT/chemotherapy osteosarcoma:Polydopamine(PDA)was coated on the surface of HCF NPs by self-polymerization of dopamine hydrochloride in a weakly alkaline solution(Tris-HCl,pH8.0).The results of transmission electron microscopy,infrared spectroscopy,zeta potential and hydrodynamic diameter showed that PDA was successfully coated on the surface of HCF NPs.The results of reactive oxygen species(ROS)probe(DCFH-DA)detection and glutathione kit showed that HCFP NPs not only promoted the production of a large number of ROS in tumor cells and had a certain temperature dependence,but also reduced the level of intracellular glutathione.HCFP NPs can promote cell apoptosis and reduce the growth rate under NIR irradiation.These results indicated that CDT/PTT based on HCFP NPs has a certain therapeutic effect on osteosarcoma.In addition,the hollow mesopore structure of HCFP NPs and the electrostatic interaction and π-π stacking interaction between PDA and DOX made the DOX load onto HCFP NPs efficiently,and their release behavior showed pH-and photothermal-response.Both in vitro cell and in vivo animal experiments confirmed that HCFP@DOX NPs showed excellent anti-osteosarcoma effect,achieving the synergistic CDT/PTT/chemotherapy for osteosarcoma.(2)Study on the anti-osteosarcoma effect of siHSF1 combined with hyperthermia and its mechanism:In view of the heat resistance problem of mild hyperthermia,small interfering RNA was innovatively used to inhibit the expression of upstream transcriptional regulatory factor HSF1 in heat shock response,so as to simultaneously inhibit the expression of multiple heat shock proteins.Subsequently,it was found that siHSF1 combined with hyperthermia could improve the mortality rate of osteosarcoma cells and inhibit cell migration.Moreover,the inhibitory mechanism was studied by immunofluorescence staining and cell cycle assay.And the results showed that siRNA inhibition of HSF1 could not only inhibit the expression of HSF1,but also inhibit the nuclear translocation of HSF1.The cells were blocked in G0/G1 phase by siHSF1 combined with hyperthermia.(3)HCFP-NH2@DOX-siRNA NPs and its synergistic CDT/PTT/chemotherapy/gene therapy for osteosarcoma:To solve the thermal resistance problem in PTT mild hyperthermia,HCFP NPs was firstly aminated with APTES to obtain a large number of positively charged amino groups on their surface.The loading of siRNA on the HCFP-NH2 was realized through electrostatic action and π-π stacking interaction.Fluorescence microscopy and flow cytometry assay showed that HCFP-NH2 could successfully delivery DOX and siRNA into osteosarcoma cells at the same time and effectively reduce the expression of HSF1.Finally,in vitro cell and in vivo animal experiments,it was found that HCFP-NH2@DOX-siRNA has good antitumor effect under mild temperature.(4)Study on the antibacterial effect and its mechanism of HCFP NPs:Aiming at the thorny problem of infection during tumor treatment,the anti-bacterial effect and its mechanism of HCFP NPs under the CDT and PTT were studied.The results of bacterial colony and live/dead staining showed HCFP NPs had good antibacterial performance against planktonic bacteria and even bacteria on the surface of the implant.The possible bacterial mechanism was may be as below:HCFP NPs adsorbed on the bacterial membrane,and then HCFP NPs converted near infrared light into heat under NIR irradiation,so that the temperature of the bacterial membrane increased,the bacterial membrane permeability increased,resulting in the outflow of bacterial DNA.In addition,Fenton reaction can occur based on HCFP NPs,and the increase of PTT temperature can further increase the Fenton reaction rate,produce a large number of hydroxyl radicals,and then cause the death of bacteria.In summary,in this study,aiming at the clinical scientific issues of osteosarcoma treatment,the novel Fenton agent CuFe2O4 and its composite material were used as a vector to load chemotherapy drug and siRNA to achieve multimode therapy,providing a new strategy for the treatment of osteosarcoma. |
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