Construction And Evaluation Of Upconversion Photothermal/photodynamic Therapy System And Copper Sulfide Chemodynamic Therapy System

Background and ObjectivePhotodynamic therapy(PDT)and chemodynamic therapy(CDT)are the treatments that generate reactive oxygen species(ROS)to kill tumors.PDT possesses some advantages including of high selectivity,less invasion and strong adaptability.However,PDT is greatly limited in the clinical application,resulting from poor light penetration,potent phototoxicity and high expression of hypoxia inducible factor-1α(HIF-1α)in tumor cells.CDT mainly relies on the Fenton reaction or Fenton-like reaction of transition metals and H2O2 which highly expressed in tumors to generate hydroxyl radicals(·OH)to damage tumor cells.Meanwhile,chemodynamic therapy is not restricted by the hypoxic environment of tumor,and the·OH generated from CDT can induce ferroptosis in tumor cells,which is a promising therapy for tumor treatment.In order to improve the therapeutic effect of PDT in tumor treatment,this research selects upconversion nanoparticles(UCNPs)and curcumin(Cur)as photodynamic carrier and photosensitizer to construct upconversion photodynamic system.To overcome the limitation of monotherapy of PDT,gold nanorods(Au NRs)and targeted ligands phenylboronic esters(PBE)were introduced into PDT system to obtain a targeted photothermal/photodynamic system.The tumor suppression effect of targeted photothermal/photodynamic system was investigated.In addition,we also synthesize copper sulfide nanoparticles(CuS NPs),preliminarily evaluating their chemodynamic properties and the ability to induce ferroptosis in tumor cells.Methods(1)Preparation and evaluation of PDT system:UCNPs were prepared through solvent thermal method and coated with mesoporous silica(mSiO2)to obtain UCNPs/mSiO2.UCNPs/mSiO2/Cur were prepared after the Cur loaded into UCNPs/mSiO2.The structure of the system was characterized and its antitumor efficacy and safety were evaluated in vitro.(2)Preparation and evaluation of PDT/PTT system:Au NRs were prepared by the seed growth method.Then,MUA-Cur was synthesized through esterification of 11-Mercaptoundecanoic Acid(MUA)with Cur.MUA-Cur and HS-PEG-COOH were simultaneously modified onto the surface of Au NRs to acquire Au NRs/Cur.Then,UCNPs were modified with Polyallylamine(PAAm)to obtain amino-functionalized NH2-UCNPs,and the NH2-UCNPs were coupled with Au NRs/Cur via amide bonds to construct Au NRs/Cur/UCNPs.To fabricate a targeted system,the PBE was chemical coupled with Au NRs/Cur/UCNPs.The final product(Au NRs/Cur/UCNPs/PBE)was gained as a targeted photothermal/photodynamic system.We also characterize the function of the system and evaluate its antitumor efficacy and safety in vitro.(3)Preparation and evaluation of CuS NPs:CuS NPs were prepared by hydrothermal method and its chemodynamic properties were investigated.Subsequently,we evaluated the cytotoxicity of CuS NPs both in normal cells and tumor cells.Furthermore,the ferroptosis induced by CuS NPs was verified,and the regulation of related signaling pathway of Nuclear factor erythroid-2-related actor 2/Heme oxygenase 1(Nrf2/HO-1)were also examined.Results(1)Au NRs and UCNPs prepared by seed growth method and solvothermal method possess uniform particle size and good dispersibility.Under near-infrared laser irradiation,Au NRs produce photothermal effects,while UCNPs have high efficiency of optical conversion which can convert near-infrared light into blue light.(2)UCNPs/mSiO2 prepared by template method have suitable mesoporous size and uniform morphology.In vitro ROS measurement found that UCNPs/mSiO2/Cur produced ROS under laser irradiation.Cytotoxicity assay results showed that UCNPs/mSiO2/Cur system exert photodynamic effect on tumor cells and produce cytotoxicity under the laser irradition.(3)The transmission electron microscope results of the Au NRs/Cur/UCNPs system showed that UCNPs successfully coupled to the surface of Au NRs/Cur.The significant change of the particle size and zeta potential of Au NRs/Cur/UCNPs/PBE caused by PBE coupling.UV-Vis spectroscopy also indicated that the Au NRs/Cur/UCNPs/PBE system was successfully constructed.MTT assay exhibited that Au NRs/Cur/UCNPs/PBE had outstanding cytotoxicity to A375 and B16 cells under near-infrared laser irradiation.The results of intracellular ROS detection showed that the amount of ROS produced by the Au NRs/Cur/UCNPs/PBE group was significantly higher than other groups.Flow cytometry analysis displayed that Au NRs/Cur/UCNPs/PBE mainly induced apoptosis in A375 and B16 cells.(4)CuS NPs which prepared by hydrothermal method produced uniform particle size and excellent dispersibility.In vitro ROS measurement found that CuS NPs generate singlet oxygen and hydroxyl radicals in the presence of H2O2.Cytotoxicity result demonstrated that CuS NPs exert potent inhibitory effect in tumor cells than normal cells.Furthermore,inhibitor of ferroptosis improved the cell viability of CuS NPs,these results indicated that CuS NPs induced ferroptosis in tumor cells.According to BODIPY581/591-C11 results,CuS NPs were consistent with erastin,which could induce the accumulation of lipid peroxides in cells.The results of qPCR and Western blot indicated that CuS NPs upregulated the expression of Nrf2 and HO-1 in tumor cells.ConclusionThis research provided the preparation of upconversion photodynamic system and proved is photodynamic effect.However,the tumor inhibition of the PDT alone is not ideal.To improve the anti-cancer effect,we prepared the targeted PTT/PDT system and it significantly enhanced the therapeutic effect,indicating that the combination therapy is more beneficial to the antitumor treatment.In addition,we found that CuS NPs had potent chemodynamic properties and triggered ferroptosis in tumor cells through the Nrf2/HO-1 signaling pathway.