Abstracts the body are composed of multiple layers of cells, forming three-dimensional (3D) structures. In addition, breast cancer cells secrete signals to neighboring cells that stimulates migration to other regions of the body, so utilizing a 2D surface limits the actual amount of signaling that takes place. Therefore, we aim to study breast cancer cells on a 3D surface because they will ideally behave more closely to how they would in the body. Our 3D system for modeling breast cancer metastasis to bone will be composed of chitosan-based hydrogel scaffolds that will be modified to mimic two different tissue types (soft breast tissue and hard bone tissue). Preliminary studies to evaluate breast cancer cell viability on plain chitosan scaffolds were performed using three breast cancer cell lines of varying subtype, including MCF-7, MDA-MB-231, and HCC1806 cells. Results from the preliminary studies indicated that the chitosan-based scaffolds were able to support breast cancer cell growth. Current and future work will include development of protocols for fabricating and characterizing the composite bone scaffold consisting of varying concentrations of chitosan and calcium phosphate to help answer the question of how the degree of stiffness of bone affects tumor cell behavior.
member minerals with little weathering are biotite and muscovite, while the other end member is thoroughly weathered kaolinite soils. Bedrock at the Calhoun Experimental Forest is Neoproterozoic gneiss, which shows a progression of micas, interlayered vermiculite, vermiculite, smectite, interlayered kaolin-smectite, and kaolin with increasing depth. In shallow depths of older profiles, kaolin-smectite interlayering should be apparent due to the long time for weathering and erosion. Smectite should be seen at greater depths of younger profiles using the same reasoning. From 240 XRD patterns of varying depths and methods, smectite interlayering begins at 40 centimeters at the hardwood site and at 100 centimeters at the pine site. This data is consistent with the predictions of where smectite interlayering should be found. Identifying Novel CAAX Motifs Using YDJ1 as a Reporter Michael Christian Morgan, CURO Summer Fellow Dr. Walter K Schmidt, Biochemistry and Molecular Biology, Franklin College of Arts and Sciences CAAX proteins are commonly involved in carcinogenesis and many are targets of therapeutic strategies. Mutations in Ras GTPase proteins- a subset of CAAX proteins- cause roughly a third of all human cancers and 95% of all pancreatic cancer. To better understand the signal transduction pathways that involve CAAX proteins, the Schmidt lab investigates the posttranslational modifications (PTMs) that regulate the activities of CAAX proteins. CAAX proteins receive three distinct modifications at their Cterminus: isoprenylation, proteolysis and carboxylmethylation. Using the yeast model, the Schmidt lab has recently discovered a novel branch to the standard PTM pathway herein referred to as the shunt pathway. In this pathway, CAAX proteins complete isoprenylation but are not subsequently modified. Ydj1 is a heat-shock protein that uses the shunt pathway. This project takes advantage of Ydj1p to identify CAAX motifs that promote isoprenylation. A plasmid library encoding Ydj1 CAAX mutants was created by standard molecular biology techniques (e.g. PCR), transformed into yeast, and screened for motifs that promote isoprenylation using a Ydj1-
Clay Mineral Concentration with Depth and Land Use History in the Critical Zone in Calhoun, South Carolina Tony Moraes, CURO Research Assistant Dr. Paul A Schroeder, Geology, Franklin College of Arts and Sciences History of land use at the Critical Zone Observatory (CZO) in Calhoun, South Carolina has been well documented and studied. Land use, climate, biotic factors and topography all contribute to rates of chemical denudation (mass loss) and chemical weathering (mineral transformations). This comparative study contrasts clay mineral assemblages in a hardwood plot, which has not had recent anthropogenic influence, and an adjacent reforested pine plot that has been historically farmed. Methods used to characterize the soil cores taken from the respective plots include X-ray diffraction of oriented clay fraction with treatments of K-, Mg-, and Na- saturation in the air-dried, ethylene glycol (EG), and heated (100O, 330O, and 550OC) states. Based on weathering intensities, early end 165