In-vivo studies of targeted and localized cancer drug release from microporous poly-di-methyl-siloxane (PDMS) devices for the treatment of triple negative breast cancer.

Triple-negative breast cancer (TNBC) treatment is challenging and frequently characterized by an aggressive phenotype and low prognosis in comparison to other subtypes. This paper presents fabricated implantable drug-loaded microporous poly-di-methyl-siloxane (PDMS) devices for the delivery of targeted therapeutic agents [Luteinizing Hormone-Releasing Hormone conjugated paclitaxel (PTX-LHRH) and Luteinizing Hormone-Releasing Hormone conjugated prodigiosin (PG-LHRH)] for the treatment and possible prevention of triple-negative cancer recurrence. In vitro assessment using the Alamar blue assay demonstrated a significant reduction (p < 0.05) in percentage of cell growth in a time-dependent manner in the groups treated with PG, PG-LHRH, PTX, and PTX-LHRH. Subcutaneous triple-negative xenograft breast tumors were then induced in athymic female nude mice that were four weeks old. Two weeks later, the tumors were surgically but partially removed, and the device implanted. Mice were observed for tumor regrowth and organ toxicity. The animal study revealed that there was no tumor regrowth, six weeks post-treatment, when the LHRH targeted drugs (LHRH-PTX and LHRH-PGS) were used for the treatment. The possible cytotoxic effects of the released drugs on the liver, kidney, and lung are assessed using quantitative biochemical assay from blood samples of the treatment groups. Ex vivo histopathological results from organ tissues showed that the targeted cancer drugs released from the implantable drug-loaded device did not induce any adverse effect on the liver, kidneys, or lungs, based on the results of qualitative toxicity studies. The implications of the results are discussed for the targeted and localized treatment of triple negative breast cancer.

Drug-encapsulated blend of PLGA-PEG microspheres: in vitro and in vivo study of the effects of localized/targeted drug delivery on the treatment of triple-negative breast cancer.

Triple-negative breast cancer (TNBC) is more aggressive and difficult to treat using conventional bulk chemotherapy that is often associated with increased toxicity and side effects. In this study, we encapsulated targeted drugs [A bacteria-synthesized anticancer drug (prodigiosin) and paclitaxel] using single solvent evaporation technique with a blend of FDA-approved poly lactic-co-glycolic acid-polyethylene glycol (PLGA_PEG) polymer microspheres. These drugs were functionalized with Luteinizing Hormone-Releasing hormone (LHRH) ligands whose receptors are shown to overexpressed on surfaces of TNBC. The physicochemical, structural, morphological and thermal properties of the drug-loaded microspheres were then characterized using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Dynamic Light Scattering (DLS), Nuclear Magnetic Resonance Spectroscopy (NMR), Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). Results obtained from in vitro kinetics drug release at human body temperature (37 °C) and hyperthermic temperatures (41 and 44 °C) reveal a non-Fickian sustained drug release that is well-characterized by Korsmeyer-Peppas model with thermodynamically non-spontaneous release of drug. Clearly, the in vitro and in vivo drug release from conjugated drug-loaded microspheres (PLGA-PEG_PGS-LHRH, PLGA-PEG_PTX-LHRH) is shown to result in greater reductions of cell/tissue viability in the treatment of TNBC. The in vivo animal studies also showed that all the drug-loaded PLGA-PEG microspheres for the localized and targeted treatment of TNBC did not caused any noticeable toxicity and thus significantly extended the survival of the treated mice post tumor resection. The implications of this work are discussed for developing targeted drug systems to treat and prevent local recurred triple negative breast tumors after surgical resection.

Degradable porous drug-loaded polymer scaffolds for localized cancer drug delivery and breast cell/tissue growth.

This paper presents the results of a combined experimental and analytical study of blended FDA-approved polymers [polylactic-co-glycolic acid (PLGA), polyethylene glycol (PEG) and polycaprolactone (PCL)] with the potential for sustained localized cancer drug release. Porous drug-loaded 3D degradable PLGA-PEG and PLGA-PCL scaffolds were fabricated using a multistage process that involved solvent casting and particulate leaching with lyophilization. The physicochemical properties including the mechanical, thermal and biostructural properties of the drug-loaded microporous scaffolds were characterized. The release of the encapsulated prodigiosin (PG) or paclitaxel (PTX) drug (from the drug-loaded polymer scaffolds) was also studied experimentally at human body temperature (37 °C) and hyperthermic temperatures (41 and 44 °C). These characteristic controlled and localized in vitro drug release from the properties of the microporous scaffold were analyzed using kinetics and thermodynamic models. Subsequently, normal breast cells (MCF-10A) were cultured for a 28-day period on the resulting 3D porous scaffolds in an effort to study the possible regrowth of normal breast tissue, following drug release. The effects of localized cancer drug release on breast cancer cells and normal breast cell proliferation are demonstrated for scenarios that are relevant to palliative breast tumor surgery for 16 weeks under in vivo conditions. Results from the in vitro drug release show a sustained anomalous (non-Fickian) drug release that best fits the Korsmeyer-Peppas (KP) kinetic model with a non-spontaneous thermodynamic process that leads to a massive decrease in breast cancer cell (MDA-MB-231) viability. Our findings from the animal suggest that localized drug release from drug-based 3D resorbable porous scaffolds can be used to eliminate/treat local recurred triple negative breast tumors and promote normal breast tissue regeneration after surgical resection.

LHRH-Conjugated Drugs as Targeted Therapeutic Agents for the Specific Targeting and Localized Treatment of Triple Negative Breast Cancer.

Bulk chemotherapy and drug release strategies for cancer treatment have been associated with lack of specificity and high drug concentrations that often result in toxic side effects. This work presents the results of an experimental study of cancer drugs (prodigiosin or paclitaxel) conjugated to Luteinizing Hormone-Releasing Hormone (LHRH) for the specific targeting and treatment of triple negative breast cancer (TNBC). Injections of LHRH-conjugated drugs (LHRH-prodigiosin or LHRH-paclitaxel) into groups of 4-week-old athymic female nude mice (induced with subcutaneous triple negative xenograft breast tumors) were found to specifically target, eliminate or shrink tumors at early, mid and late stages without any apparent cytotoxicity, as revealed by in vivo toxicity and ex vivo histopathological tests. Our results show that overexpressed LHRH receptors serve as binding sites on the breast cancer cells/tumor and the LHRH-conjugated drugs inhibited the growth of breast cells/tumor in in vitro and in vivo experiments. The inhibitions are attributed to the respective adhesive interactions between LHRH molecular recognition units on the prodigiosin (PGS) and paclitaxel (PTX) drugs and overexpressed LHRH receptors on the breast cancer cells and tumors. The implications of the results are discussed for the development of ligand-conjugated drugs for the specific targeting and treatment of TNBC.

Anomalous Release Kinetics of Prodigiosin from Poly-N-Isopropyl-Acrylamid based Hydrogels for The Treatment of Triple Negative Breast Cancer.

This paper presents the anomalous release kinetics of a cancer drug (prodigiosin) frompoly-n-isopropyl-acrylamide (P(NIPA))-based gels. The release exponents, n, which correspond to the drug release mechanisms, were found to be between 0.41 and 1.40. This is within a range that include Fickian case I (n = 0.45) and non-Fickian diffusion (case II) (n > 0.45) for cylindrical drug-loaded structures. The results, however, suggest that the release exponents, n, correspond mostly to anomalous case II and super case II transport mechanics with sigmoidal characteristics. The drug release kinetics of the P(NIPA)-based hydrogels are well described by bi-dose functions. The observed drug release behavour is related to the porosity of the hydrogels, which can be controlled by cross-linking and copolymerization with acrylamide, which also improves the hydrophilicity of the gels. The paper also presents the effects of cancer drug release on cell survival (%), as well as the cell metabolic activities of treated cells and non-treated cells. The implications of the results are discussed for the development of implantable thermosensitive gels for the controlled release of drugs for localized cancer treatment.

Multilayer cellular stacks of gelatin-hydroxyapatite fiber scaffolds for bone tissue engineering.

Multilayer cellular stacks of crosslinked, electrospun 25 wt % hydroxyapatite (HA)-gelatin and pure gelatin fiber scaffolds, seeded with human fetal osteoblasts (hFOBs), were studied for up to 18 days in static and dynamic cell culture. Two types of stack models were investigated: a four-layer stack with cells seeded at the bottom surface of the first/top layer and the top surface of the fourth/bottom layer, so that the two middle layers were not seeded with cells with the aim to act as continuing conduits of culture medium and nutrients supply to the adjacent cell-populated zones; a three-layer stack with cells seeded at the bottom surface of each layer. hFOBs exhibited lower migration rate through the stack thickness for the 25 wt % HA-gelatin scaffolds as compared to the pure gelatin scaffolds, due to the small pores of the former. Hence, the regularly seeded three-layer stack maintained cell-free porous zones in all layers through which the culture medium could continuously perfuse, while good fusion was achieved at the interface of all layers via the cross-migrating cells with a preference to downwards vertical migration attributed to gravity. Dynamic cell culture conditions enhanced overall cell growth by about 6% for the regularly seeded three-layer stack. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 779-789, 2017.

Electrospinning of nanocomposite fibrillar tubular and flat scaffolds with controlled fiber orientation.

Electrospinning was used in innovative electrospinning rigs to obtain tubular and flat fibrous structures with controlled fiber orientation with the aim to be used as scaffolds for biomedical applications, more specifically in the tissue engineering of vascular and orthopedic grafts. Gelatine and hydroxyapatite (HA)-gelatine solutions of various compositions were tried and electrospinning of continuous fibers was maintained for gelatine and up to 0.30 g/g HA-gelatine solutions in 2,2,2-trifluoroethanol (TFE). Small diameter tubular scaffolds were electrospun with axial fiber orientation and flat scaffolds were cut from fiber mats electrospun around a wired drum substrate. The fibrous mats were crosslinked using a glutaraldehyde solution and subjected to image analysis of SEM micrographs, water swelling tests, and mechanical testing. Fiber diameter in the electrospun scaffolds could be varied depending on the feed solution concentration and composition whereas fiber orientation was affected by the processing conditions. After crosslinking, the 0.30 g/g HA-gelatine scaffolds absorbed the minimum amount of water after 48 h soaking and they had the highest Young's modulus, 60 MPa, and highest strength, 3.9 MPa.