Layer-by-Layer nanotheranostics loading docetaxel and enzalutamide with improved targeting, imaging and therapeutic effects for prostate cancer

Prostate cancer (PCa) is the most common malignant tumor in men and, after lung cancer, the second leading cause of cancer death. Currently, androgen deprivation therapy (ADT) has become the standard of care for men with locally advanced or metastatic prostate cancer. However, after undergoing ADT for 18 to 24 months, most patients develop castration-resistant prostate cancer (CRPC). Depending on the stage of CRPC, the recommended first-line treatment regimens include chemotherapy with docetaxel (DTX) and novel hormonal agents, such as enzalutamide (ENZ). Combination therapy with DTX and ENZ for CRPC is expected to be successful in the future. To achieve this goal, it is critical to design a drug delivery system with distinct pharmacokinetic actions for both drugs. Owing to advances in materials science, nanoparticle (NP) technology is a proved strategy for developing an efficient a cancer treatment regimen In this thesis, PSMA-targeted, DTX and ENZ co-loaded nanotheranostics for both PCa imaging and therapy were designed and conceptually validated. Particularly, the system’s ability to perform bioimaging is related to the use of quantum dots (QDs). The primary issue with the application of QDs in biological applications is their toxicity. In this study, carbon QDs (CQDs) derived from natural sources (chitin) were used to ensure their cytocompatibility. High-resolution transmission electron microscopy (HRTEM), UV-Vis, and fluorescence analyses have been performed to examine the physicochemical and morphological characteristics of the CQDs. The results showed a size of the CQDs between 2 and 10 nm, a positive charge, and an emission peak at 400 nm. Then, the cytotoxicity of CQDs on neo-dermal fibroblasts was evaluated by using Presto Blue and Live/Dead assays. The results showed high cellular viability-up up to a concentration of CQDs 500 μg/mL. Following that, the nanotheranostic systems were designed and manufactured with a nanocore composed of calcium phosphate (CaP) containing DTX and stabilized by PAH deposition via a pumping method. Using the layer-by-layer assembly technique, successive layers of two oppositely charged natural polysaccharides were deposited on the core of the system via electrostatic interactions. In this study, chitosan (CHI) and furcellaran (FUR) were used as natural polysaccharides for the deposition of four layers. Three systems have been developed to assess the individual and synergistic effects of DTX and ENZ. Moreover, prostate-specific membrane antigen (PSMA) is overexpressed on the surfaces of PCa cells. Thus, a small-molecule PSMA ligand (PSMA-617) was grafted on the outermost layer of nanotheranostics to enhance cancer cell-specific targeting, uptake, and retention. The final system was characterized through chemical-physical and morphological studies. The efficacy and cytotoxicity of the proposed treatment were evaluated. Cellular tests were conducted on two different types of prostate cancer cells, LNCap and VCap. The results showed that the concentrations of DTX and ENZ currently used in various formulations were too low to have a significant cytotoxic effect on cells. Increasing the concentration of both drugs was required. Furthermore, the presence of polysaccharides in the system resulted in high biocompatibility for both cell lines, but with a greater effect in the case of LNCaps. Finally, 3D models of VCap tumor cells were created to assess the proposed system’s efficacy in the most biomimetic and reliable manner possible.