PCL-based nanoparticles for doxorubicin-ezetimibe co-delivery: A combination therapy for prostate cancer using a drug repurposing strategy

Introduction: Drug repurposing is an effective strategy for identifying the use of approved drugs for new therapeutic purposes. This strategy has received particular attention in the development of cancer chemotherapy. Considering that a growing body of evidence suggesting the cholesterol-lowering drug ezetimibe (EZ) may prevent the progression of prostate cancer, we investigated the effect of EZ alone and in combination with doxorubicin (DOX) on prostate cancer treatment. Methods: In this study, DOX and EZ were encapsulated within a PCL-based biodegradable nanoparticle. The physicochemical properties of drug containing nanoparticle based on PCL-PEG-PCL triblock copolymer (PCEC) have been exactly determined. The encapsulation efficiency and release behavior of DOX and EZ were also studied at two different pHs and temperatures. Results: The average size of nanoparticles (NPs) observed by field emission scanning electron microscopy (FE-SEM) was around 82±23.80 nm, 59.7±18.7 nm, and 67.6±23.8 nm for EZ@PCEC, DOX@PCEC, and DOX+EZ@PCEC NPs, respectively, which had a spherical morphology. In addition, DLS measurement showed a monomodal size distribution of around 319.9, 166.8, and 203 nm hydrodynamic diameters and negative zeta potential (-30.3, -6.14, and -43.8) mV for EZ@PCEC, DOX@PCEC, and DOX+EZ@PCEC NPs, respectively. The drugs were released from the NPs sustainably in a pH and temperature-dependent manner. Based on the MTT assay results, PCEC copolymer exhibited negligible cytotoxicity on the PC3 cell line. Therefore, PCEC was a biocompatible and suitable nano-vehicle for this study. The cytotoxicity of the DOX-EZ-loaded NPs on the PC3 cell line was higher than that of NPs loaded with single drugs. All the data confirmed the synergistic effect of EZ in combination with DOX as an anticancer drug. Furthermore, fluorescent microscopy and DAPI staining were performed to show the cellular uptake, and morphological changes-induced apoptosis of treated cells. Conclusion: Overall, the data from the experiments represented the successful preparation of the nanocarriers with high encapsulation efficacy. The designed nanocarriers could serve as an ideal candidate for combination therapy of cancer. The results corroborated each other and presented successful EZ and DOX formulations containing PCEC NPs and their efficiency in treating prostate cancer.