Optimization and Development of Selective Histone Deacetylase Inhibitor (MPT0B291)-Loaded Albumin Nanoparticles for Anticancer Therapy

Preparation of bovine serum albumin nanospheres via desolvation: a study of synthesis, characterization, and aging

Serum albumin has myriad uses in biotechnology, but its value as a nanocarrier or nanoplatform for therapeutics is becoming increasingly important, notably with albumin-bound chemotherapeutics. Another emerging field is the fabrication of biopolymeric nanoparticles using albumin as a building block to achieve highly-tunable nonimmunogenic capsules or scaffolds that may be cheaply and reliably produced. The aim of this study was to characterize and optimize the desolvation process used for fabrication of albumin nanoparticles under ambient conditions, studying both glutaraldehyde (GT) and glucose (GLU) as crosslinking agents and the effect of various synthesis conditions including pH, electrolyte concentration, and rate of desolvation on particle size and stability. Particle size, polydispersity index, and zeta potential were investigated, morphology was examined using scanning electron microscopy (SEM), and long-term stability and degradation modes were studied using dynamic light scattering (DLS) and transmission electron microscopy (TEM). It was determined that the optimized synthesis procedure for synthesis of Bovine Serum Albumin (BSA) nanoparticles at the investigated scale under ambient conditions was addition of ethanol at a rate of 0.625 mL min-1via infusion against the vial wall and a pH of 9 with the addition of no other electrolytes. Optimized BSA nanoparticles were synthesized at a size of 86 ± 3.7 nm (σ = 1.85) using glutaraldehyde as a crosslinker and a size of 92 ± 1.9 nm (σ = 0.95) using glucose as a crosslinker with polydispersity indices of 0.08 and 0.05, respectively. Nanoparticles synthesized via the optimized procedure, using both crosslinkers, were found to maintain colloidal stability significantly longer than cases previously reported in the literature, with insignificant changes in hydrodynamic size many months after synthesis.

Unveiling the Potential of Nanosuspension Formulation Strategy for Improved Oral Bioavailability of Gefitinib

Gefitinib (GB), an oral tyrosine kinase inhibitor suffers major setbacks in clinical application due to limited aqueous solubility leading to poor oral bioavailability. Nanosuspension serves as a promising formulation strategy to overcome the above-mentioned drawbacks. Hence, the present study involves the development of gefitinib nanosuspension (GB-NS) using High-pressure homogenization (HPH) to increase its aqueous solubility and maximize oral bioavailability. GB-NS was optimized by utilizing the quality-by-design strategy to optimize independent variables such as homogenization pressure, drug-to-stabilizer ratio, and number of cycles. Lecithin was found to stabilize the nanosuspension with optimal particle size, PDI, and zeta potential of 157 ± 18.77 nm, 0.296 ± 0.040, and -33.25 respectively. Intriguingly, a drug-to-stabilizer ratio significantly influenced (p < 0.005) particle size and PDI, establishing its crucial role in optimization. The morphological characterization by SEM of GB-NS revealed a rod-shaped structure. Thereafter, the thermal and powder X-ray analysis depicted the crystalline nature of gefitinib in GB-NS. Additionally, GB-NS exhibited enhanced saturation solubility (~ 2.4- and ~ 3.4-fold) and dissolution rate (~ 2.5- and ~ 3.5-fold) compared to pure GB in 0.1 N HCl and PBS 6.8 respectively. GB-NS remained stable under both storage conditions ( 25°C and 4°C). Finally, the pharmacokinetic study depicted a considerable increase in Cmax (~ 2.84-fold) and AUC(0-t) (~ 3.87-fold) of GB-NS when compared to free GB. Therefore, developed formulations showed a competent solution for enhancing the oral bioavailability of poor water-soluble drugs.

Differential cellular responses to FDA-approved nanomedicines: an exploration of albumin-based nanocarriers and liposomes in protein corona formation

Albumin nanoparticles (NPs) and PEGylated liposomes have garnered tremendous interest as therapeutic drug carriers due to their unique physicochemical properties. These unique properties also have significant effects on the composition and structure of the protein corona formed around these NPs in a biological environment. Herein, protein corona formation on albumin NPs and liposomes was simultaneously evaluated through in vitro and simulation studies. The sizes of both types of NPs increased with more negatively charged interfaces upon being introduced into fetal bovine serum. Gel electrophoresis and label-free quantitative proteomics were performed to identify proteins recruited to the hard corona, and fewer proteins were found in albumin NPs than in liposomes, which is in accordance with isothermal titration calorimetry. The cellular uptake efficiency of the two NPs significantly differed in different serum concentrations, which was further scrutinized by loading an anticancer compound into albumin NPs. The presence of the hard protein corona increased the cellular uptake of albumin NPs in comparison with liposomes. In our simulation study, a specific receptor present in the membrane was greatly attracted to the albumin-apolipoprotein E complex. Overall, this study not only evaluated protein corona formation on albumin NPs, but also made promising advancements toward albumin- and liposome-based therapeutic systems.

JNTX-101, a novel albumin-encapsulated gemcitabine prodrug, is efficacious and operates via caveolin-1-mediated endocytosis

Albumin is an attractive candidate carrier for the development of novel therapeutic drugs. Gemcitabine has been FDA approved for the treatment of solid tumors; however, new drugs that optimize gemcitabine delivery are not available for clinical use. The aim of this study was to test the efficacy of a novel albumin-encapsulated gemcitabine prodrug, JNTX-101, and investigate whether Cav-1 expression predicts the therapeutic efficacy of JNTX-101. We first determined the treatment efficacy of JNTX-101 in a panel of pancreatic/lung cancer cell lines and found that increases in Cav-1 expression resulted in higher uptake of albumin, while Cav-1 depletion attenuated the sensitivity of cells to JNTX-101. In addition, decreased Cav-1 expression markedly reduced JNTX-101-induced apoptotic cell death in a panel of cells, particularly in low-serum conditions. Furthermore, we tested the therapeutic efficacy of JNTX-101 in xenograft models and the role of Cav-1 in JNTX-101 sensitivity using a Tet-on-inducible tumor model in vivo. Our data suggest that JNTX-101 effectively inhibits cell viability and tumor growth, and that Cav-1 expression dictates optimal sensitivity to JNTX-101. These data indicate that Cav-1 correlates with JNTX-101 sensitivity, especially under nutrient-deprived conditions, and supports a role for Cav-1 as a predictive biomarker for albumin-encapsulated therapeutics such as JNTX-101.

Polymers Enhancing Bioavailability in Drug Delivery

A drug's bioavailability, i.e., the extent to and rate at which it enters the systemic circulation, thus accessing the site of action, is largely determined by the properties of the drug [...].

A Novel Thermal-driven Self-assembly Method to Prepare Albumin Nanoparticles: Formation Kinetics, Degradation Behavior and Formation Mechanism

Nanoparticles based on bovine serum albumin (BSA), which shares 76% homology with human serum albumin (HSA), have emerged as a promising candidate for the efficient delivery of anticancer drugs. Thermal-driven self-assembly is a novel organic solvent-free approach to produce albumin nanoparticles. In our previous study, some features of this nanoparticle such as drug loading efficiency, drug encapsulation efficiency and drug release kinetics have been evaluated. However, the formation mechanism that determines the above nanoparticle properties remains unclear. Here, we investigated the formation kinetics and mechanism using spectroscopic methods including fluorescence spectroscopy, circular dichroism (CD) and differential scanning calorimetry (DSC). We also applied chemical analysis methods that measured the content changes of albumin active groups and vanillin. To verify the covalent networks in the nanoparticles, trypsin and glutathione (GSH) were used separately to cleave the peptide bonds and disulfide bridges, and dynamic light scattering (DLS) and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) were used to analyze the degraded samples. BSA nanoparticles started to form at 10 min and were completely formed at 120 min. With the digestion of trypsin, more than 50% of the nanoparticles were degraded within 60 min. CD spectra showed that α-helical structure of BSA decreased from 42.3% to 39.8% and 37.7% after heating for 10 and 60 min, respectively. In the DSC thermogram, the melting peak of BSA nanoparticles was 229.14℃, which is about 12℃ higher than the physical mixture of BSA and vanillin, indicating that chemical reactions occurred during the nanoparticle formation and formed a new more stable substance. Moreover, the results of active group assay, GSH degradation and SDS-PAGE experiments also proved that disulfide bonds and peptide bonds were formed between BSA molecules, whereas Schiff bases were formed between BSA and vanillin molecules. Formation kinetics and degradation behavior are important properties to characterize albumin nanoparticles and should be paid attention to. Not only that, this study also provides an effective way to study the formation mechanism of protein-based nanodrug delivery systems.

Current Strategies in Breast Cancer Therapy: Role of Epigenetics and Nanomedicine

Breast cancer (BC), the most common cancer in women, is incurable due to metastatic spread to distant organs. The existence of epigenetic dysregulation has been shown to contribute to the progression and even metastasize through the transition from epithelial to mesenchymal. Behind failure strategies of conventional treatments, fruitful outcomes of epigenetic drugs have provided the hope of solid tumor management where the reversal of acquired resistance of the cancer cells is possible by epigenome regulation. Several agents have been identified to target epigenetic regulators in the cancer cells exhibiting remarkable potential against solid tumors, including BC. However, unnecessary systemic exposure, solubility issues, and unsuitability for diseased conditions using conventional delivery systems limit their use as cancer therapeutics. The progression of nanotechnology in pharmaceutical delivery has revolutionized cancer therapy, where specific, targeted and efficient delivery of epigenetic agents for alteration of cancerous conditions are ensured. In this review, a focus is made on epigenetic alteration in BC condition with the deliverable potential of the nanocarriers toward the breast tumor microenvironment for proper management. The significance of targeting and controlled release of therapeutics in the improved targeting of cancer cells is highlighted.

The role of histone deacetylase 3 in breast cancer

It has been recently revealed that Histone Deacetylase (HDAC) 3, a unique member of the HDACs family, can trigger and progress cancers by alternation in genes expression and proteins activity. Epigenetic modifications by HDACs have been studied well in various cancer cells. Recent studies have focused on the HDAC enzymes as a possible target in cancer therapy. There are significant documents on upregulation of HDAC3 in breast cancer (BC) cells which suggest an oncogenic role for this enzyme. Interestingly, some studies showed that HDAC3 inhibition could be considered as a promising target in breast cancer therapy, and thus far, several inhibitors from different nature have been introduced. In this review, we discussed the function and highlight the existing inhibitors of HDAC3 in BC pathogenesis and therapy.