Co-delivery Of A Tumor Microenvironment-responsive Disulfiram Prodrug And CuO₂ Nanoparticles For Preliminary Antitumor Study

Disulfiram(DSF)is a clinically commonly used drug for alcohol withdrawal and has been used for more than 70 years.Previous studies have found that DSF has a significant inhibitory effect on tumor growth in tumor therapy,especially under the mediation of copper.DSF is a divalent metal ion chelator,which is degraded into diethyldithiocarbamate(DDC)after metabolism in vivo.After binding to copper ions,chelation occurs to trigger the production of reactive oxygen species(ROS).However,the poor stability of DSF in vivo leads to some side effects or limited therapeutic effect,which impedes its further application in tumor therapy.Herein,we utilized a simple strategy to synthesize ROS-responsively released DSF prodrug,which could be released responsively in the acidic tumor microenvironment through co-delivery of CuO2 nanoparticles.Poly amino acids were used as a platform to combine with the DSF prodrug through B-N interaction,and then encapsulated CuO2 nanoparticles,Cu@P-B nanoparticles were obtained.In the acidic tumor microenvironment,CuO2 nanoparticles loaded on the Cu@P-B nanoparticles were released and decomposed to produce Cu2+,causing cellular oxidative stress.At the same time,the increased ROS would accelerate the release and activation of the DSF prodrag,and further chelated the released Cu2+ to generate the noxious copper diethyldithiocarbamate complex,thereby effectively causing apoptosis.The product was characterized by nuclear magnetic resonance,gel permeation chromatography,transmission electron microscopy,and dynamic light scattering,proving successful preparation of the desired product.Element content was determined by inductively coupled plasma atomic emission spectrometry,and then drug concentration and encapsulation efficiency were calculated.The biological activity of the prepared nanoparticles was verified by cell experiments and animal experiments.Experimental results showed that the obtained product was consistent with the target product through nuclear magnetic resonance technology and gel permeation chromatography test.The results of transmission electron microscope pictures showed that the prepared nanoparticles P-B and Cu@P-B were spherical and uniform in size.The dynamic light scattering test results showed that the size of P-B was about 55 nm,and that of Cu@P-B was about 100 nm.Cytotoxicity tests revealed that Cu@P-B could effectively kill cancer cells with only a small amount of Cu2+(0.18 μg/mL),and significantly inhibited the viability of tumor cells.It was also showed that Cu@P-B increased ROS level in the tumor sites.The results of mitochondrial membrane potential detection demonstrated a significant reduction in membrane potential,indicating that Cu@P-B could induce apoptosis of tumor cells.The results of woundhealing test and invasion test showed that Cu@P-B nanoparticles significantly inhibited the migration and invasion of tumor cells.The hemolysis test result and the result of animal tissue sections also indicated that Cu@P-B has well biological safety.The above results demonstrated that Cu@P-B had a significant inhibitory effect on tumor growth with limited toxic side effects,showing a new perspective in DSF prodrug design and tumor treatment.