Copper-based Nanomaterials For Prostate Cancer Therapy

Research background:Prostate cancer is the most frequently malignancy of the male genitourinary system,and its morbidity and mortality ranks second and fifth,respectively,in all masculine malignancies worldwide according to GLOBOCAN statistics of the World Health Organization（WHO）in 2020.At present,the main treatment options of prostate cancer include surgery,endocrine therapy,radiotherapy,and chemotherapy,but they all have certain limitations,including severe hemorrhage,dysuria,erectile dysfunction,high price,and so on.Therefore,it is imperative to explore a new,safe,and effective treatment method for Prostate cancer.As an indispensable trace element in the human body,copper（Cu）is widely involved in various biological processes closely related to growth and metabolism of the body,such as cell metabolism,proliferation,and angiogenesis.In addition,copper-based nanomaterials play a very important role in the field of nanomedicine,especially in tumor diagnosis and treatment,due to their good biocompatibility,unique physicochemical properties,and tunable nanostructures.They are mainly divided into the following aspects:（1）Copper-based nanomaterials,as excellent Fenton-like reagents,can convert hydrogen peroxide（H₂O₂）into reactive oxygen species（ROS）in the tumor microenvironment（TME）,which can be used for chemodynamic therapy（CDT）of tumors;（2）Copper-based nanomaterials can be used as photosensitizers to produce ROS under specific wavelength light excitation,which can be used for photodynamic therapy（PDT）of tumors;（3）Copper-based nanomaterials with strong optical absorption in the near-infrared（NIR）region can serve as attractive photothermal agents for photothermal therapy（PTT）of tumors;（4）Copper-based nanomaterials have great potential as contrast agents in tumor imaging such as photoacoustic imaging（PAI）,computed tomography（CT）,and magnetic resonance imaging（MRI）.Therefore,copper-based nanomaterials can provide a nanoplatform with multiple diagnostic and therapeutic modalities to realize the synergistic treatment of tumors.Due to the good prospect of copper-based nanomaterials in tumor treatment,this thesis investigated its application in the treatment of prostate cancer.Research objectives:This thesis aimed to construct two multifunctional copper-based nanoplatforms Cu-MNCS-AIPH@PAA and CuSA-DOX@COD.The specific research objectives were as follows:1.Characterizing the morphology and properties of two nanoplatforms and investigating their therapeutic effects and mechanisms on prostate cancer at the cellular and animal levels.2.Preliminary study on the application of nanozyme platform in immunotherapy for prostate cancer.Research methods:1.The metal-organic framework Cu-ZIF-8 was first synthesized as the template,and then copper doped mesoporous carbon nanosphere（Cu-MNCS）was successfully obtained by programmed high-temperature pyrolysis under argon atmosphere.2,2’-azobis[2-（2-imidazolin-2-yl）propane]-dihydrochloride（AIPH）was loaded into Cu-MNCS and polyacrylic acid（PAA）was used to functionalize the surface of nanoparticles.Finally,the Cu-MNCS-AIPH@PAA nanoplatform was prepared.A variety of detection methods were used to characterize the physicochemical properties of Cu-MNCS-AIPH@PAA nanoplatform such as morphology,size,structure,and elemental composition.The photothermal effect,hydroxyl radicals（·OH）and the alkyl radicals production ability were further investigated.The therapeutic effect of Cu-MNCS-AIPH@PAA nanoplatform on prostate cancer through the cooperative effect of PTT,CDT,and alkyl radicals generation was studied at the cellular and animal levels.The long-term toxicity of nanoplatform in vivo was also studied.2.The metal-organic framework Cu-ZIF-8 was first synthesized as the template,and then a single-atom copper embedded nitrogen-doped mesoporous carbon nanozyme（CuSA）was successfully obtained by programmed high-temperature pyrolysis under nitrogen atmosphere.Chemotherapy drug doxorubicin（DOX）and cholesterol oxidase（COD）were loaded into CuSA nanozyme.Finally,the CuSA-DOX@COD nanozyme platform was prepared.A variety of detection methods were used to characterize the physicochemical properties of CuSA-DOX@COD nanozyme platform such as morphology,size,structure,and elemental composition.The multi-enzyme simulated activities and cholesterol depletion were further investigated.The immunotherapeutic effect of CuSA-DOX@COD nanozyme platform for prostate cancer was studied at the cellular and animal levels.Research results:1.We had successfully prepared Cu-MNCS nanosphere with a diameter of approximately 170 nm.Cu-MNCS nanoparticles had a large specific surface area and typical mesoporous structure.A variety of detection methods were used to confirm the successful preparation of Cu-MNCS-AIPH@PAA nanoplatform.The drug loading capacity of AIPH was 7.73%.Cu-MNCS@PAA nanoparticles with excellent photothermal conversion efficiency（42.4%）and photothermal stability could serve as good photothermal agent for PTT.Through the combination of photothermal effect,Fenton-like reaction,and alkyl radicals generation,Cu-MNCS-AIPH@PAA nanoplatform could effectively kill prostate cancer cells,inhibit tumor growth,and have no significant toxicity.2.We had successfully prepared CuSA nanocubes with a side length of approximately 150 nm.A variety of characterization results proved that Cu presented in single atoms form,and Cu coordinated with the nitrogen atom in the support（Cu-N₄）.A variety of detection methods were used to confirm the successful preparation of CuSA-DOX@COD nanozyme platform.The drug loading capacity of AIPH and COD were 5.55%and 10.66%,respectively.CuSA nanozyme exhibited good catalase-like（CAT-like）and peroxidase-like（POD-like）activities,which could catalyze the conversion of H₂O₂ to oxygen（O₂）and·OH,respectively.Meanwhile,CuSA nanozyme exhibited good glutathione oxidase-like（GSHOx-like）activity to deplete reduced glutathione（GSH）and enhance ROS production.The loaded COD could oxidize cholesterol to generate H₂O₂ and the loaded DOX could further kill tumor cells through chemotherapy.The CuSA-DOX@COD nanozyme platform could induce immunogenic cell death（ICD）of prostate cancer cells,which could release damage associated molecular patterns（DAMPs）to promote dendritic cell（DC）maturation and furthermore activate the body’s anti-tumor immune response.CuSA-DOX@COD nanozyme platform could not only effectively inhibit the growth of primary tumors through synergistic therapy,but also activate anti-tumor immune responses to significantly inhibit the growth of distal tumors.Conclusion:1.We constructed a multifunctional nanoplatform based on PAA modified Cu doped mesoporous carbon nanosphere to load AIPH（Cu-MNCS-AIPH@PAA）for highly efficient stimuli-responsive prostate cancer therapy with low adverse effect.Due to the strong absorption in the NIR region,Cu-MNCS-AIPH@PAA nanoplatform exhibited high photothermal conversion efficiency,which could not only act as a good photothermal agent for PTT,but also trigger AIPH to produce the alkyl radicals.In response to the specificity of TME,including low content of endogenous H₂O₂ and mild acid,Cu-MNCS-AIPH@PAA nanoplatform could generate·OH through Fenton-like reaction for CDT,and its efficacy was further improved by photothermal effect.The good anticancer effect of Cu-MNCS-AIPH@PAA nanoplatform was demonstrated in vitro and in vivo by synergistic effect of CDT,PTT,and alkyl radicals.Therefore,Cu-MNCS-AIPH@PAA was a promising nanoplatform for prostate cancer therapy with the good biocompatibility and excellent anticancer efficiency.2.We constructed a copper-based single-atom nanozyme platform loading with DOX and COD（CuSA-DOX@COD）.CuSA nanozyme exhibited excellent POD-like activity,CAT-like activity,and GSHOx-like activity,which could catalyze the production of·OH and O₂ by tumor cellular H₂O₂,deplete GSH,and further disrupt the antioxidative defense system（ADS）.The O₂ generated during the catalytic reaction could not only relieve the hypoxia in TME,but also provide an oxygen source for the cholesterol oxidation.Moreover,the loaded COD could not only reduce the cholesterol content of tumor cells to increase the cell membrane permeability and inhibit tumor cell proliferation and invasion,but also oxidize cholesterol to increase the level of H₂O₂in tumor cells to enhance catalytic efficiency.In addition,the loaded DOX could further kill tumor cells through chemotherapy.Both in vitro and in vivo studies showed that CuSA-DOX@COD nanozyme platform could induce the ICD of prostate cancer cells to remold the immunosuppressive TME through by the synergistic effect of ROS storm,chemotherapy and cholesterol depletion,activating the systemic anti-tumor immunity to treat prostate cancer.Consequently,CuSA-DOX@COD nanozyme platform provided a novel strategy for immunotherapy of prostate cancer.