The Application And Action Mechanism Of Functionalized SeNPs Combined With Metformin As Anti-tumor Therapy Agents

Due to the extremely complicated mechanism of tumor development,the current traditional treatment strategies are still difficult to effectively suppress the malignant progression of tumors.As the main means of cancer treatment,the serious toxic to normal cells and multi-drug resistance of chemotherapeutic drugs limit their widely application in clinic.At the same time,the low sensitivity of tumor cells to immune cells such as natural killer cells?NK?makes it difficult for current tumor immunotherapy strategies to effectively exert anti-tumor effects.Metformin,as a clinical drug for type II diabetes mellitus?T2DM?,possesses the hypoglycemic effect,and can also reduce the incidence of tumors in patients and inhibit the growth of tumor cells.In recent years,a large number of clinical data indicate that combined therapy may be the key strategy to solve the poor efficacy of single strategy on tumor.With the rapid development of nanotechnology,nanomaterials show good application prospects in the field of tumor diagnosis and treatment by the virtue of their unique physical and chemical properties.Selenium?Se?,as an essential trace element of the human body,can play a key role in maintaining the normal life activities of the body by regulating the expression of related selenoproteins.More importantly,Se nanoparticle?Se NPs?exerts many biological activities,such as anti-cancer,anti-virus,anti-bacterial and anti-oxidation,etc.,and can treat diabetes by regulating the level of oxidative stress in cells.Therefore,this paper will make full use of the unique biological function of Se NPs,systematically study its biological safety by regulating its surface chemical properties.At the same time,we systematically evaluate synergistic antitumor effect and potential action mechanism of Se NPs combined with metformin.Furthermore,we roughly studied synergistically kill the tumor,and the preliminary research the action mechanism of Se NPs and metformin combination with NK cell immunotherapy.The detail results are as follows:1)The stability and body toxicity of nanomaterials play an important role for their further biological applications.The sole Se NPs are poorly stable and easy to reunite.Polymers can stabilize Se NPs through electrostatic binding and chemical adsorption.Therefore,we utilize different polymers to modify the surface of Se NPs to obtain functionalized Se NPs with different charges,effectively enhanced the stability and biological activity.The characterization by means of particle size,Zeta potential,UV,TEM and HR-TEM verified that the functionalized Se NPs have good stability in different media.The systematic toxicity evaluation of PTR-Se NPs was carried out.In acute oral toxicity,the LD₅₀ of PTR-Se NPs in female mice are 17.1 g/kg BW,in male mice are 20.0 g/kg BW,in rats are greater than 10 g/kg BW.In subchronic oral toxicity,the NOAEL level of PTR-Se NPs is 0.055 g/kg BW.The results confirmed that PTR-Se NPs is non-toxicity nanomaterials at less than the dose range of 0.055g/kg BW.2)Diabetic patients have their own characteristics such as oxidative stress and chronic inflammation,which constantly stimulate the body and increase the incidence of tumors.Therefore,the functionalized Se NPs combined with metformin for tumor treatment were studied by different drug treatment methods in this chapter.It was found that TW80-Se NPs combined with metformin had a synergistic anti-tumor effect on MCF-7 cells under different dosage treatment.And we further investigate the anti-tumor mechanism through flow cytometry,cell cloning experiment,ROS change level,mitochondrial membrane potential change and western blot protein analysis.TW80-Se NPs combined with metformin mainly affects the level of intracellular ROS,increase the expression level of DNA damage-related proteins such as p-ATM/p-ATR,p-Histone,p-p38 protein,promotes the expression of p21,and further inhibits CDK/cyclin related protein and up-regulates expression of p15.The combined treatment also may affect the p-AMPK signaling pathway and the mitochondrial membrane potential to induce cell cycle arrest to affect cell growth and proliferation,achieve a synergistic therapeutic effect.3)Due to the presence of hyperglycemia and hyperinsulinemia in diabetic patients,the synthesis and metabolism of liver glycogen is affected and long-term chronic inflammation and other adverse stimuli lead to a decline in immune system function,further aggravating the occurrence of liver tumors.Therefore,we use the unique biological functions of Se NPs and metformin to achieve a synergisticly sensitizing effect on NK cells,especially those derived from cancer patients.We systematically inpuire the anti-tumor effect of functionalized Se NPs and metformin combined with NK-92 cells in Hep G-2 cells after different dosage treatment.It was found that functionalized Se NPs can enhance the immunotherapy effect of NK-92 cells.After the functionalized Se NPs combined with metformin pre-treatment with Hep G-2 cells,the therapeutic effect after adding NK-92 cells is more significant.Among them,TW80-Se NPs combined with metformin exhited the best enhancement effect on NK-92 cells.The interaction of them is explored by detecting the experission level of the surface receptors of tumor cells and NK-92 cell and monitoring the level of ROS inside tumor cells after combined treatment.The possible mode of interaction is that TW80-Se NPs combined with metformin increase the level of ROS in Hep G-2 cells,upregulate the expression levels of ULBP-3/4 and MICA/B on tumor cell surface,and the expression levels of Fas L on NK-92 cell surface to enhance the combination of NK-92 cells and tumor cells,thereby enhancing the effect of immunotherapy.This study will provide important information for us to more scientifically and accurately understand the biological effects of Se NPs and its future application in the field of biomedicine,as well as an important reference for the development of safer and more effective new strategies for combined cancer treatment.