Effects of Polymer 3D Architecture, Size, and Chemistry on Biological Transport and Drug Delivery In Vitro and in Orthotopic Triple Negative Breast Cancer Models.

The size, shape, and underlying chemistries of drug delivery particles are key parameters which govern their ultimate performance in vivo. Responsive particles are desirable for triggered drug delivery, achievable through architecture change and biodegradation to control in vivo fate. Here, polymeric materials are synthesized with linear, hyperbranched, star, and micellar-like architectures based on 2-hydroxypropyl methacrylamide (HPMA), and the effects of 3D architecture and redox-responsive biodegradation on biological transport are investigated. Variations in "stealth" behavior between the materials are quantified in vitro and in vivo, whereby reduction-responsive hyperbranched polymers most successfully avoid accumulation within the liver, and none of the materials target the spleen or lungs. Functionalization of selected architectures with doxorubicin (DOX) demonstrates enhanced efficacy over the free drug in 2D and 3D in vitro models, and enhanced efficacy in vivo in a highly aggressive orthotopic breast cancer model when dosed over schedules accounting for the biodistribution of the carriers. These data show it is possible to direct materials of the same chemistries into different cellular and physiological regions via modulation of their 3D architectures, and thus the work overall provides valuable new insight into how nanoparticle architecture and programmed degradation can be tailored to elicit specific biological responses for drug delivery.

Metabolism-based isolation of invasive glioblastoma cells with specific gene signatures and tumorigenic potential.

BACKGROUND: Glioblastoma (GBM) is a highly aggressive brain tumor with rapid subclonal diversification, harboring molecular abnormalities that vary temporospatially, a contributor to therapy resistance. Fluorescence-guided neurosurgical resection utilizes the administration of 5-aminolevulinic acid (5-ALA) generating individually fluorescent tumor cells within a background population of non-neoplastic cells in the invasive tumor region. The aim of the study was to specifically isolate and interrogate the invasive GBM cell population using a novel 5-ALA-based method. METHODS: We have isolated the critical invasive GBM cell population by developing 5-ALA-based metabolic fluorescence-activated cell sorting. This allows purification and study of invasive cells from GBM without an overwhelming background "normal brain" signal to confound data. The population was studied using RNAseq, real-time PCR, and immunohistochemistry, with gene targets functionally interrogated on proliferation and migration assays using siRNA knockdown and known drug inhibitors. RESULTS: RNAseq analysis identifies specific genes such as SERPINE1 which is highly expressed in invasive GBM cells but at low levels in the surrounding normal brain parenchyma. siRNA knockdown and pharmacological inhibition with specific inhibitors of SERPINE1 reduced the capacity of GBM cells to invade in an in vitro assay. Rodent xenografts of 5-ALA-positive cells were established and serially transplanted, confirming tumorigenicity of the fluorescent patient-derived cells but not the 5-ALA-negative cells. CONCLUSIONS: Identification of unique molecular features in the invasive GBM population offers hope for developing more efficacious targeted therapies compared to targeting the tumor core and for isolating tumor subpopulations based upon intrinsic metabolic properties.

Adjuvant chemotherapy for brain tumors delivered via a novel intra-cavity moldable polymer matrix.

INTRODUCTION: Polymer-based delivery systems offer innovative intra-cavity administration of drugs, with the potential to better target micro-deposits of cancer cells in brain parenchyma beyond the resected cavity. Here we evaluate clinical utility, toxicity and sustained drug release capability of a novel formulation of poly(lactic-co-glycolic acid) (PLGA)/poly(ethylene glycol) (PEG) microparticles. METHODS: PLGA/PEG microparticle-based matrices were molded around an ex vivo brain pseudo-resection cavity and analyzed using magnetic resonance imaging and computerized tomography. In vitro toxicity of the polymer was assessed using tumor and endothelial cells and drug release from trichostatin A-, etoposide- and methotrexate-loaded matrices was determined. To verify activity of released agents, tumor cells were seeded onto drug-loaded matrices and viability assessed. RESULTS: PLGA/PEG matrices can be molded around a pseudo-resection cavity wall with no polymer-related artifact on clinical scans. The polymer withstands fractionated radiotherapy, with no disruption of microparticle structure. No toxicity was evident when tumor or endothelial cells were grown on control matrices in vitro. Trichostatin A, etoposide and methotrexate were released from the matrices over a 3-4 week period in vitro and etoposide released over 3 days in vivo, with released agents retaining cytotoxic capabilities. PLGA/PEG microparticle-based matrices molded around a resection cavity wall are distinguishable in clinical scanning modalities. Matrices are non-toxic in vitro suggesting good biocompatibility in vivo. Active trichostatin A, etoposide and methotrexate can be incorporated and released gradually from matrices, with radiotherapy unlikely to interfere with release. CONCLUSION: The PLGA/PEG delivery system offers an innovative intra-cavity approach to administer chemotherapeutics for improved local control of malignant brain tumors.

Apoferritin-encapsulated PbS quantum dots significantly inhibit growth of colorectal carcinoma cells.

Colorectal carcinoma (CRC) is the 3rd most common cancer worldwide, thus development of novel therapeutic strategies is imperative. Herein potent, selective dose-dependent antitumor activity of horse spleen apoferritin encapsulated PbS quantum dots (AFt-PbS) against two human-derived colorectal carcinoma cell lines is reported (GI50∼ 70 µg mL-1). Following in vitro exposure to AFt-PbS, CRC cells fail to recover proliferative capacity, and undergo apoptosis triggered by the generation of reactive oxygen species (ROS). In stark contrast, the AFt-PbS nanocomposites do not affect the growth and cell cycle of non-tumor human microvessel endothelial HMEC-1 cells (GI50 > 500 µg mL-1). In vivo, AFt-PbS QDs are well tolerated by mice. Neither adverse health nor behavioral indicators were observed throughout the 15 day study. The photoluminescence of AFt-PbS combined with selective antitumor activity offer potential development of AFt-PbS for simultaneous non-invasive imaging and treatment of malignant tissue.

An LC-MS-MS method for quantitative determination of maraviroc (UK-427,857) in human plasma, urine and cerebrospinal fluid.

Maraviroc is a first-in-class CCR5 antagonist that shows potent anti-HIV-1 activity in vitro and in vivo and is well tolerated in both healthy volunteers and HIV-1-infected patients. The method for determination of maraviroc (UK-427,857) and its major metabolite (UK-408,027) in human plasma consists of a protein-precipitation procedure and analysis by liquid chromatography/tandem mass spectrometry using positive ion TurboIonSpray® ionization and multiple reaction monitoring. The assay has been validated over a concentration range of 0.500-500 ng/mL for both analytes. The determinations of maraviroc in human cerebrospinal fluid (0.500-500 ng/mL) and in urine (5.00-5000 ng/mL) have also been validated but do not include measurement of the metabolite. The validations included extraction recovery, intra-assay and inter-assay precision and accuracy, stability of stock and spiking solutions, freeze-thaw stability, matrix stability, processed-extract stability, and evaluation of potential interferences from selected medications in plasma or urine.