Development of Abiraterone Acetate Nanocrystal Tablets to Enhance Oral Bioavailability: Formulation Optimization, Characterization, In Vitro Dissolution and Pharmacokinetic Evaluation.

Abiraterone acetate is a prodrug of abiraterone used in combination with prednisone as a standard therapeutic strategy for hormone-resistant prostate cancer (mCRPC). Due to the poor solubility and permeability, the release and absorption of abiraterone acetate are low and reduce its bioavailability. In this project, abiraterone acetate tablets prepared using nanocrystal technology were developed to overcome the drawbacks of normal tablets by enhancing in vitro dissolution rate and oral bioavailability. The abiraterone acetate nanocrystal suspensions were prepared by top-down wet milling method using a planetary ball mill with the mixture of Poloxamer 407 and Poloxamer 188 as the optimized stabilizer at a ratio of 7:1. The optimized nanocrystals were freeze-dried and characterized using DLS, TEM, DSC, and XRD. The abiraterone acetate nanocrystal tablets significantly improve the in vitro dissolution rate of abiraterone acetate compared to raw materials. Although exhibiting a similar dissolution rate compared to the Zytiga® tablets, the nanocrystal tablets significantly improve the oral bioavailability with Cmax and AUC0-t being 3.51-fold and 2.80-fold higher, respectively, in the pharmacokinetic study. The present data indicate that nanocrystal is a promising strategy for improving the dissolution and bioavailability of abiraterone acetate.

A Regulatory Loop Involving Notch and Wnt Signaling Maintains Leukemia Stem Cells in T-Cell Acute Lymphoblastic Leukemia.

Leukemia-initiating cells play critical role in relapse, resistance to therapies and metastases but the mechanism remains largely elusive. We report that ß-catenin is over-expressed in almost all T-ALL patients and flow sorted ß-cateninhigh fractions are highly resistant to therapy, leading to liver metastases in nude mice as well as dysregulated lncRNAs. Pharmacological inhibition through XAV-939 as well as si-RNA mediated inhibition of ß-catenin is initially effective in re-sensitization to therapy, however, prolonged inhibition shifts dependency from ß-catenin to Notch signaling, with particularly high levels of receptors Notch 1 and Notch 2. The results are verifiable in a cohort of T-ALL patients comprising of responders vs. those who have progressed, with ß-catenin, Notch 1 and Notch 2 elevated in progressed patients. Further, in patients-derived cells, silencing of Notch 1 or Notch 2 does not counter resistance to ß-catenin inhibition, rather pharmacological pan-Notch inhibition is needed to overcome resistance and its effect on in vitro tumor sphere formations as well as in vivo liver metastases. Thus, wnt and Notch signaling are part of a regulatory loop mutually compensating for each other in T-ALL, while ensuring the maintenance of stem cell phenotype.

Highly loaded deoxypodophyllotoxin nano-formulation delivered by methoxy polyethylene glycol-block-poly (D,L-lactide) micelles for efficient cancer therapy.

Cancer is a kind of malignant diseases that threatens human health and the research application of anti-tumor drug therapeutics is growingly always been focused on. Many new compounds with great anticancer activity were synthesized but cannot be hard to be developed into clinical use due to its poor water solubility. Deoxypodophyllotoxin (DPT) is just an example. We develop lyophilized Deoxypodophyllotoxin (DPT) loaded polymeric micelles using methoxy polyethylene glycol-block-Poly (D, L-lactide) (mPEG-PLA). DPT-PM freeze-dried powder was successfully prepared using optimized formulation. mPEG-PLA was added to hydration media before hydrating as cryoprotectants. The freeze-dried powder exhibited white pie-solid without collapsing, and the particle size of DPT-PM reconstituted with water was about 20-35 nm. The entrapment efficiency of the reconstituted solution was 98%, which shows no differences with the micelles before lyophilization. In-vitro cytotoxicity and cellular uptake studies showed that DPT-PM has a higher degree of cytotoxicity comparing with DPT and mPEG-PLA micelles and uptake of mPEG-PLA was concentration and time-dependent. In vivo characterization of DPT-PM was done for pharmacokinetics behaviors, antitumor activity and safety. The obtained results showed significant improvement in plasma clearance bioavailability (p <0.05) and prolonged blood circulation time comparing with DPT-HP-ß-CD. Moreover, mPEG-PLA micelles had a better degree of anti-tumor efficacy, this was due to better accumulation of mPEG-PLA in tumor cell via enhanced permeability and retention (EPR) effect. Therefore, DPT-PM has great clinical value, and can be expected to be a novel antitumor preparation.

Preparation, characterization, and pharmacodynamics of insulin-loaded fumaryl diketopiperazine microparticle dry powder inhalation.

Purpose: With the increase of population aging and the proportion of overweight and obese, a growing number of people are suffering from diabetes. Insulin (INS) as the most widely used hypoglycemic agent was always chosen as the most effective treatment method of diabetes. In this study, fumaryl diketopiperazine (FDKP) was used as a carrier for the pulmonary delivery of insulin. Patients and methods: The INS-loaded FDKP microspheres (INS@FDKP-MPs) were prepared by spray drying and physicochemical properties (drug loading, particle size, flowability, moisture content, morphology, and crystalline state) were further investigated. Pharmacodynamics was investigated on diabetic model rats administrated by intratracheal insufflation. Results: The INS-loaded FDKP microspheres show satisfied flowability and in vitro deposition with FPF 50.2% and MMAD 3.45 ± 0.13 µm, and the blood glucose level was significantly decreased. Moreover, no inflammatory reaction was observed during the safety study. Conclusion: To sum up, the aim was to develop a non-injection system for insulin, INS@FDKP-MPs powder inhalation with high dose, low toxicity, and good lung deposition inhalation could rapidly decrease the blood glucose level without immune stimulation, which shows remarkably potential on diabetes treatment by pulmonary delivery route.

CircRNA circ_0000190 inhibits the progression of multiple myeloma through modulating miR-767-5p/MAPK4 pathway.

BACKGROUND: Multiple myeloma (MM) accounts for 10% of all hematological malignancies. Dysregulation of microRNAs (miRNAs) or long non-coding RNAs (lncRNAs) has important impacts on progression of MM. Circular RNAs (circRNAs) are correlated with malignancy in the modulation of tumor progression. This study aims to investigate the effect of circ_0000190 on regulating the progression of MM. METHOD: Microscopic examination via single molecule fluorescent in situ hybridization indicates the location of circ_0000190. qRT-PCR and Western blot were used to evaluate the expression of RNAs and proteins. Potential target of circ_0000190 was searched as miRNA, and examined by luciferase reporter assay. A computational screen was also conducted to search the potential target of miRNA. In vitro cell viability, proliferation, apoptosis assays and flow cytometric were performed to assess the effects of circ_0000190 and its target on MM. Mice model of human MM was established with subcutaneous xenograft tumor, qRT-PCR and western blot were performed to detect the underlying mechanisms of circ_0000190 on MM. RESULTS: Circ_0000190 was located in the cytoplasm, and down-regulated in both bone marrow tissue and peripheral blood, while the target of circ_0000190, miR-767-5p, was up-regulated, suggesting a negative correlation between them. The binding ability between circ_0000190 and miR-767-5p was confirmed by luciferase reporter assay. Moreover, circ_0000190 inhibited cell viability, proliferation and induced apoptosis of MM thus inhibiting cell progression, which is partially through the negative regulation of miR-767-5p. Mitogen-activated protein kinase 4 (MAPK4) is a direct target of miR-767-5p. In addition, over-expression of miR-767-5p promoted cell progression by directly targeting and regulating MAPK4. The MM model mice with administration of circ_0000190 suppressed tumor growth and progression. CONCLUSION: Our results revealed that the ability of circ_0000190 to protect against MM was inherited through repression of miR-767-5p, and miR-767-5p might be a tumor drive through targeting MAPK4. Therefore, a novel role of circ_0000190 on regulating the progression of MM was found, and the clinical application of circRNAs might represent a strategy in MM.

Acid-sensitive hybrid polymeric micelles containing a reversibly activatable cell-penetrating peptide for tumor-specific cytoplasm targeting.

Cell-penetrating peptides (CPPs) have become a novel drug delivery system due to their distinct advantages, including high cell transmembrane potency and ability to carry cargo molecules inside cells. However, owing to their cationic charge and non-specificity characteristics, the clinical application of CPPs is limited. In the current study, we engineered a reversibly activatable cell-penetrating peptide (RACPP), containing oligoarginine fused to a pH-sensitive masking sequence via a polyglycine linker ((HE)10G5R6 or HE-CPP) with ultra-pH-sensitivity. The HE-CPP sequence was coupled to the surface of polyethyleneglycol-polylactic acid (PEG-PLA) polymer micelles (PMs-HE-CPP) to realize improve specificity and targeted delivery of encapsulated paclitaxel (PTX). PTX/PMs-HE-CPP showed the satisfactory encapsulated efficiency, loading capacity, size distribution as well as reversible charge-conversion in response to the surrounding pH. The zeta potential of PMs-HE-CPP was negative at pH 7.5, moderately positive at pH 6.5, and even more positive at a lower pH. Coumarin 6-loaded PMs-HE-CPP (C6/PMs-HE-CPP) showed enhanced tumor cellular uptake at a mildly acidic tumor microenvironment (pH 6.5) via energy-dependent and clathrin-mediated endocytosis. Furthermore, PTX/PMs-HE-CPP had significantly higher cytotoxicity toward mice breast cancer (4T1) cells at pH 6.5 versus at pH 7.4. In vivo imaging studies in 4T1-BALB/c tumor xenograft models confirmed the tumor-targeting characteristic of PMs-HE-CPP. PTX/PMs-HE-CPP also exhibited improved anti-tumor efficacy against unmodified polymer micelles and Taxol® in this tumor model. Accordingly, not only do RACPPs show the great potential to endow CPPs with specificity and reversible net-charge converting characteristic, they are also able to improve the targeting effect of nanoparticles.

Size-based anti-tumoral effect of paclitaxel loaded albumin microparticle dry powders for inhalation to treat metastatic lung cancer in a mouse model.

In this study, we prepared paclitaxel (PTX) loaded bovine serum albumin (BSA) microparticles (MPs) of different sizes (0.5, 1.0, and 3.0 µm) and converted them into dry powders (DPs) of a uniform size (∼5.0 µm) through spray-drying techniques. The aim of preparing different sized PTX-MPs is to investigate the size-based in vivo biodistribution and retention of PTX in the lungs after intratracheal administration. Following the in vitro characterizations, the anti-tumor efficacy of the DPs containing differently sized PTX-BSA-MPs administered through intratracheal insufflation was compared with intravenously administered PTX solution (Taxol). While the fastest drug release was found for the 0.5 µm group, the 1.0 and 3.0 µm groups showed the highest anti-tumor efficiency in vivo. Taken together, our results demonstrate that the initial particle size of the incorporated particles, i.e., MPs, is crucial for the anti-tumor efficacy of DPs administered by inhalation, and the initial particle size should be regarded as one of the key factors in the development and quality control of such preparations.

Carboxymethyl chitosan-folic acid-conjugated Fe3O4@SiO2 as a safe and targeting antitumor nanovehicle in vitro.

A synthetic method to prepare a core-shell-structured Fe3O4@SiO2 as a safe nanovehicle for tumor cell targeting has been developed. Superparamagnetic iron oxide is encapsulated inside nonporous silica as the core to provide magnetic targeting. Carboxymethyl chitosan-folic acid (OCMCS-FA) synthesized through coupling folic acid (FA) with OCMCS is then covalently linked to the silica shell and renders new and improved functions because of the original biocompatible properties of OCMCS and the targeting efficacy of FA. Cellular uptake of the nanovehicle was assayed by confocal laser scanning microscope using rhodamine B (RB) as a fluorescent marker in HeLa cells. The results show that the surface modification of the core-shell silica nanovehicle with OCMCS-FA enhances the internalization of nanovehicle to HeLa cells which over-express the folate receptor. The cell viability assay demonstrated that Fe3O4@SiO2-OCMCS-FA nanovehicle has low toxicity and can be used as an eligible candidate for drug delivery system. These unique advantages make the prepared core-shell nanovehicle promising for cancer-specific targeting and therapy.