Vivo Biosciences (United States)

Glioblastoma (GBM) preclinical model systems for high throughput testing are limited by unnatural culture conditions (e.g. grown in serum) and expense (such as Patient-Derived Xenografts or PDX). While PDX can be grown in culture as neurospheres, these culture conditions do not provide key tumor microenvironment components seen in vivo. As such, there is a need for better model systems to test chemotherapy, small molecule inhibitors (SMI), and radiation. Utilizing a human-derived stromal matrix (HuBiogel, Vivo Biosciences, Birmingham, AL), we can grow GBM PDX as microtumors allowing for therapeutic testing (including combinations) in 96 and 384-well formats. Moreover, molecular “omic” testing can be performed to build companion biomarkers. GBM PDX were serially propagated in athymic nude mice through the UAB Brain Tumor Animal Models Core. PDX tumors were harvested and isolated as single cell suspensions for subsequent embedding into HuBiogel to form 3D microtumors at defined cell concentrations. These microtumors were maintained for up to 28 days, with phenotypic assays and molecular testing performed at 7-14 days. Therapies, including temozolomide, cediranib, WP1066, selumetinib, crizotinib, and radiation were tested alone or in combination. Immunohistochemistry (IHC), CellTiter-Glo, Calcein AM staining, and kinomic profiling in the UAB Kinome Core (kinomecore.com) using the PamStation®12 (PamGene, The Netherlands) were performed. We selected 7 GBM tumors from a well-characterized panel of 27 human GBM-PDX that represent the molecular subtype spectrum of disease seen in The Cancer Genome Atlas and reproduce histopathological hallmarks of GBM when grown orthotopically in mice. IHC examination of GBM PDX microtumors revealed multicellular organization replicating the in vivo tumor microenvironment. Molecular testing showed kinomic diversity in microtumors as well as differential sensitivity to chemotherapy, SMI combinations, and radiation (in combination with SMI). GBM PDX microtumors are well suited to high throughput therapeutic testing.

Blends of poliglecaprone (PGC) and polycaprolactone (PCL) of varying compositions were electrospun into tubular conduits and their mechanical, morphological, thermal and in vitro degradation properties were evaluated under simulated physiological conditions. Generally, mechanical strength, modulus and hydrophilic nature were enhanced by the addition of PGC to PCL. An in vitro degradation study in phosphate-buffered saline (pH 7.3) was carried out for up to 1 month to understand the hydrolytic degradation effect on the mechanical properties in both the longitudinal and circumferential directions. Pure PCL and 4:1 PCL/PGC blend scaffolds exhibited considerable elastic stiffening after a 1 month in vitro degradation. Fourier transform infrared spectroscopic and DSC techniques were used to understand the degradation behavior and the changes in structure and crystallinity of the polymeric blends. A 3:1 PCL/PGC blend was concluded to be a judicious blend composition for tubular grafts based on overall results on the mechanical properties and performance after a 1 month in vitro degradation study.