Construction Of HPMA Polymer Modified Gold Nanorod Drug Delivery Systems To Treat Prostate Cancer By Combined Treatment

ObjectiveProstate cancer,as one of the world's recognized major diseases,has seriously threatened the health of men.The traditional chemotherapy,surgical resection and other means can not achieve the ideal therapeutic effect.This subject intends to use gold nanorods as nanomaterials for adjuvant photothermal therapy,doxorubicin as model drug,p H sensitive hydrazone bond as spacer,HPMA polymer as drug carrier,to construct a GNRs drug-loaded system modified by HPMA polymer PDS-p HPMA-DOX@GNRs,to study the combined treatment of prostate cancer PC-3 cells with hyperthermia-chemotherapy,hoping to achieve better anti-tumor effect.Methods(1)A GNRs solution was prepared by“seed growth method”.The UV-Vis spectrophotometer was used to investigate the spectral absorption characteristics of the GNRs,the morphology of the GNRs was observed by transmission electron microscope,the particle size and potential were detected by the nanometer particle size analyzer,and the photothermal conversion ability GNRs the near infrared laser was investigated.(2)A series of polymeric monomer were synthesized,Identification of monomer structure using ¹H NMR.p HPMA-DOX and PDS-p HPMA-DOX were synthesized,Cy5.5 as a tractrace molecule,p HPMA-Cy5.5 and PDS-p HPMA-Cy5.5were synthesized.Determination of molecular weight and molecular weight distribution of HPMA polymers were detested by FPLC,The content of DOX in HPMA polymers was detected by UV-Vis spectrophotometer,and the content of Cy5.5 in HPMA polymer was detected by fluorescence spectrophotometer.(3)PDS-p HPMA-DOX@GNRs was synthesized.its physicochemical properties was characterized,Its release of DOX in different p H environments was investigated by HPLC.(4)The cytotoxicity of the combined treatment group to PC-3 cells was detected by MTT method,and the localization of the combined treatment group in PC-3 cells was observed by laser confocal electron microscope.(5)Established PC-3 bilateral tumor-bearing nude mouse model,used Cy5.5 as a fluorescent agent,investigated the tissue dynamic distribution of the NIR irradiation download drug system in nude mice,and established a PC-3 unilateral tumor-bearing nude mouse model.Results(1)Lateral and longitudinal characteristic absorption peaks of GNRs were located in 511 nm and 800 nm,The form of GNRs were regular bar structure in TEM,at the same time,it has a excellent photothermal conversion ability and good stability.(2)¹H NMR results showed that the polymeric monomers were successfully synthesized.The molecular weight of p HPMA-DOX,PDS-p HPMA-DOX,p HPMA-Cy5.5 and PDS-p HPMA-Cy5.5 were 18.459 k Da,27.745k Da,19.5k Da and21.804k Da,the PDI were 1.27,1.26,1.07 and 1.36 respectively,This indicates that the HPMA polymers have better homogeneity,the drug loading of p HPMA-DOX and PDS-p HPMA-DOX were 122.05±2.56 mg/g polymer and 117.32±3.90 mg/g polymer respectively,The content of Cy5.5 in p HPMA-Cy5.5 and PDS-p HPMA-Cy5.5 were0.26 mmol/g polymer and 0.18mmol/g polymer.(3)PDS-p HPMA-DOX@GNRs has good photothermal conversion.The results of in vitro release showed that the cumulative release of PDS-p HPMA-DOX@GNRs Laser group and PDS-p HPMA-DOX@GNRs group were 67.18%and 57.25%respectively,indicating that under the p H 5.0 weak acidic environment,the NIR irradiation would accelerate the fracture of the p H sensitive hydrazone bond and promote the release of small molecular drugs.(4)MTT results showed that the IC₅₀value of the combined treatment group was 4.24 times lower than that of the PDS-p HPMA-DOX@GNRs,indicating that the cytotoxicity of the drug loading system was significantly enhanced after the combined treatment.CLSM results showed that the combined treatment group accelerated the rate of small molecular drugs entering the nucleus.(5)The results of tissue distribution in vivo have showed that Combined treatment group has significant fluorescence response at the tumor site after 144 h,Fluorescent signal of PDS-p HPMA-Cy5.5@GNRs irradiated tumor is stronger than that of other organs,The results showed that combined therapy could increase the accumulation of drug loading system at tumor site and prolong the retention time at tumor site.In vivo antitumor activity studies have shown that,The inhibition rates of DOX group,p HPMA-DOX group,PDS-p HPMA-DOX@GNRs group and combined treatment group are 29.23%,47.67%,61.12%and 94.93%,Anti-tumor efficiency of the combined treatment group showed significant difference compared with other drug groups(p<0.05).Conclusion:This study takes GNRs as the core of hyperthermia and HPMA polymer as the modified chain to construct a GNRs drug delivery system modified by HPMA polymer PDS-p HPMA-DOX@GNRs,PC-3 as the cell model of prostate cancer and the male nude mouse as an animal model,to treat prostate cancer by combined treatment.According to the results,combined therapy accelerated the release of small molecular model drug DOX,improved the cytotoxicity of drug loading system,increased the nuclear entry rate of small molecular drugs,and increased the accumulation and retention time of drug loading system in tumor site.It has shown remarkable antitumor activity.