Nano Drug Delivery System Based On Metformin Synergistic Treatment Of Tumor

In recent years,malignant tumor diseases are seriously threatening human life.During the treatment of tumors,the hypoxic microenvironment impedes the efficiencies of photodynamic therapy?PDT?and chemotherapy.Therefore,it is necessary to regulate the tumor hypoxic microenvironment and develop efficient tumor treatment.Currently,researchers have focused on providing oxygen?O₂?to tumor sites to control hypoxia in tumor sites.However,it is known that the extent of hypoxic regions depends on blood O₂ content and the tumor's O₂ consumption.Herein,an imaging-mediated drug delivery system?DOX/Met/BSA-HA-CDs?for tumor therapy was developed,which has the following advantages:?1?Metformin?Met?reduced tumor O₂ consumption effectively,controlled tumor oxygenation;There is a difference in the release rate between doxorubicin?DOX?and Met:Met was released rapidly to reduce the tumor O₂ consumption,while DOX was released in a sustained manner,which were advantageous for improving hypoxic tumor to achieve better therapeutic effects;?2?Higher efficacy of the PDT and lower resistance for anticancer drug by reducing O₂ consumption,which successfully facilitate the outcomes of synergistic antitumor;?3?The red fluorescent carbon dots?CDs?were used not only for PDT,but also for tissue imaging in vivo.The relevant researches of this study were as follows:1.The preparation and characterization of DOX/Met/BSA-HA-CDs nanoparticles.In this study,firstly,the formamide and citric acid were used to synthesize CDs.The as-produced CDs can be used for bio-imaging in vivo and photodynamic therapy.Secondly,CDs and hyaluronic acid?HA?were used to synthesize HA-CDs conjugates by amide bond,and then the HA-CDs conjugates were linked to the surface of bovine serum albumin?BSA?to form BSA-HA-CDs,endowing nanoparticles with the function of targeting drug delivery.Finally,the drugs of DOX and Met were simultaneously encapsulated in BSA-HA-CDs nanoparticles to get DOX/Met/BSA-HA-CDs nanoparticles.The results of encapsulation efficiency,Ultraviolet-visible?Uv-vis?spectrum and Fourier transform infrared spectroscopy?FT-IR?showed that DOX/Met/BSA-HA-CDs nanoparticles were successfully synthesized.The fluorescence emission spectrum of CDs showed that the emission wavelength of CDs displayed excitation wavelength-dependent fluorescence emission characteristic,which has good fluorescence properties and can be used for fluorescence imaging in vivo.The reactive oxygen species?ROS?production of CDs and DOX/Met/BSA-HA-CDs was investigated by DPBF,indicating that CDs can produce obvious ROS under laser irradiation,and the ROS production will not be influenced when DOX/Met/BSA-HA-CDs nanoparticles were formed.The in vitro drugs release of the nanoparticles showed that the nanoparticles can promote the release of DOX under acidic conditions,and there was a difference in the release rate between DOX and Met.The release rate of Met was faster than DOX,which was beneficial to play a better tumor treatment effect.2.The antitumor efficiency of DOX/Met/BSA-HA-CDs in vitro.In this study,the human anti-doxorubicin breast cancer?MCF-7/ADR?cells and the human breast cancer?MCF-7?cells were used as cell models to investigate the cell survival rate of DOX/Met/BSA-HA-CDs,ROS detection and Western blot experiments.The cell viability experiment results indicated that in the presence of Met,the DOX/Met/BSA-HA-CDs combined with PDT and chemotherapy under laser irradiation could significantly increase the inhibition rate of cancer cells.The ROS kit was used to detect the production of ROS in the cells,and the results showed that the ROS yield of the DOX/Met/BSA-HA-CDs group was higher.The Western blot analysis showed that DOX/Met/BSA-HA-CDs could inhibit the expression of HIF-1?and P-gp protein,which confirmed that nanoparticles can down-regulate hypoxia-related proteins and overcome multi-drug resistance of DOX.The above experiment results showed that DOX/Met/BSA-HA-CDs could control tumor hypoxia,enhance the therapeutic effect of PDT and chemotherapy,and has significant anti-tumor effect in vitro.3.In vivo imaging and pharmacodynamics studies of DOX/Met/BSA-HA-CDs.In this experiment,female Kunming mice were used as experimental animals,and the S180 ascites tumor cell lines were used to establish an animal model.The in vivo pharmacodynamics and fluorescence imaging of the DOX/Met/BSA-HA-CDs nanoparticles were investigated.Ex vivo immunofluorescence staining showed that the signal of HIF-1?in the DOX/Met/BSA-HA-CDs group was significantly decreased,indicating that the nanoparticles can effectively control tumor hypoxia.The in vivo pharmacodynamics was evaluated by the change in mouse tumor volume.The DOX/Met/BSA-HA-CDs with laser irradiation group had more obvious therapeutic effect than the photodynamic therapy group or the chemotherapy group alone,indicating that the synergistic therapeutic effect of hypoxia-related therapies was realized in the presence of Met.The results of mouse body weight and HE staining pathological sections showed that DOX was more toxic to the mouse body,however,the nanoparticles had good biocompatibility and no obvious side effects on the mouse body.In addition,the DOX/Met/BSA-HA-CDs nanoparticles utilized CDs for fluorescence imaging to monitor the distribution of nanoparticles in vivo.