Our students are required to complete a thesis as a culmination of their studies in the College of Biomedical Sciences. The thesis can be either a traditional laboratory-based project or a Capstone project. The substantial research project that is submitted shows the development of the student’s scientific approach to problem solving and critical thinking.
MS Program Thesis Schedules & Abstracts
Tuesday, November 14, 2017
Location: Jefferson Alumni Hall Rm. M61
9:30 AM: Andrea Flynn-MSPR
INHIBITION OF PROTEIN SYNTHESIS WITH POLYAMINE DEPLETION IN HIGH-RISK NEUROBLASTOMA
A Flynn, M Hogarty; Children’s Hospital of Philadelphia and University of Pennsylvania School of Medicine, Philadelphia, PA
We aimed to characterize the prevalence of ODC1 amplification and to determine the mechanism(s) by which polyamine depletion leads to decreased protein synthesis in neuroblastoma. MYC genes are oncogenic drivers in neuroblastoma, a lethal pediatric tumor, and they coordinately deregulate programs that result in biomass creation. Polyamine synthesis is one such program that supports protein synthesis. Ornithine decarboxylase (encoded by ODC1) is the rate-limiting enzyme in polyamine synthesis, a direct MYC target, and a bonafide oncogene. Difluoromethylornithine (DFMO) is a clinically available irreversible inhibitor of the Odc, and DFMO inhibits tumor progression in murine models of neuroblastoma. We hypothesized that DFMO inhibits protein translation as a principal mechanism of anti-tumor activity. Polyamines support protein translation in part via effects on eIF5A and the eIF4F complex, yet their relative contributions remain poorly defined. We studied 23 neuroblastoma cell lines and 916 primary tumors via SNP-array and/or qPCR analysis. ODC1 amplification was found exclusively in MYCN-amplified tumors, though amplification peaks were distinct. ODC1 amplification was identified in 33 of 256 (13%) MYCN-amplified primary tumors and 3 of 13 (23%) MYCN-amplified cell lines. Using the puromycin-incorporation assay we showed a decrease in global protein synthesis, more notably in MYCN- and MYCN/ODC1-amplified cells, with DFMO. Inhibition of both eIF5A activation and colony formation were seen at DFMO exposures achievable in humans based on previous adult pharmacokinetic data. No significant changes in phosphorylation of 4EBP1 (a member of the eIF4F complex) were seen with DFMO, but were seen with mTORC inhibition as previously shown. This work suggests changes in polyamine-dependent activation of eIF5A may be a significant mechanism by which DFMO inhibits protein synthesis and MYCN amplification may be a biomarker of response.
10:00 AM: Nicholas Mazzanti-MSBS
FACTORS LIMITING THE SENSITIVITY AND EFFICIENCY OF ENGINEERED CAR T & CAR NK CELLS
N. Mazzanti1, Y. Sykulev1,2,3
Departments of 1Microbiology and Immunology and 2Medical Oncology, 3The Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA
The use of cytolytic effector cells endowed with chimeric antigen receptors (CAR) to combat various cancer malignancies has recently gained significant attention. Although engineered CAR-bearing effector cells have offered encouraging results, many aspects of CAR technology require further scrutiny. Here we equip cord blood derived T cells and NK92 cells with a CAR specific for high molecular weight melanoma associated antigen (HMW-MAA) to investigate factors that influence CAR signaling. Furthermore, we differentiate CAR and TCR signaling capacity to highlight challenges that remain for optimization and utilization of CAR constructs. When compared in parallel, both cord blood derived T cells and NK92 cells revealed some advantages and disadvantages as the CAR-bearing effector cells. Our data suggest that CAR signaling capacity is heavily influenced by the number of available target antigens present on tumor cells. We also found that CAR T cells activated through the TCR exercise superior effector responses compared to that of CAR-mediated activation. Likewise, the level of CAR expression on the surface of effector cells may also influence the efficiency of the effector cell response. These data suggest that CAR engagement results in less efficient signaling that hinders the triggering of sufficient effector responses. The mechanisms of CAR activation and signaling remain unclear and thus require further exploration to fully understand and enhance the technology. Efforts to evaluate differences in proximal signaling mediated by CAR and TCR are currently under way.
10:30 AM: Lila Mukhtarzada-MSMI
PROTEOME ANALYSIS OF CHEMOKINES IN BLISTER FLUIDS OF EPIDERMOLYSIS BULLOSA PATIENTS: IMPLICATION FOR STEM CELL THERAPY.
L. Mukhtarzada2, O. Igoucheva1,2,3
1 National Institute of Arthritis and Musculoskeletal and Skin Diseases of the Nation Institutes of Health.
2 Department of Dermatology and Cutaneous Biology, Thomas Jefferson University, Philadelphia PA
3 Debra Foundation, Chile and Mexico
Hereditary epidermolysis bullosa (EB) is associated with skin blistering and the development of chronic non-healing wounds. Although clinical studies have shown that cell-based therapies improve wound healing, recruitment of therapeutic cells to blistering skin and to more advanced skin lesions remains a challenge. Here, we analyzed cytokines and chemokines in blister fluids (BF) of patients affected by dystrophic, junctional and simplex EB. Our analysis revealed high levels of CXCR1, CXCR2, CCR2 and CCR4 ligands, particularly dominant in dystrophic and junctional EB. In vitro migration assays demonstrated preferential recruitment of CCR4+ lymphocytes and CXCR1+, CXCR2+ and CCR2+ myeloid cells toward EB-derived BF. Immuno-phenotyping of skin-infiltrating leukocytes confirmed substantial infiltration of the EB-affected skin with resting (CD45RA+) and activated (CD45RO+) T cells and CXCR2+ CD11b+ cells, many of which were identified as CD16b+ neutrophils. Our studies also showed that abundance of CXCR2 ligand in BF creates a favorable milieu for the recruitment of the CXCR2+ stem cells.
Wednesday, November 15, 2017
Location: Jefferson Alumni Hall, Room M61
3:00 PM: Jacquelyn Olavarria-MSCB
PROTEOMIC SCREENS OF CHEMOTACTIC MOLECULES IN CONGENITAL MUSCULAR DYSTROPHY-AFFECTED MUSCLES: POTENTIAL FOR ADULT STEM CELLS THERAPY
J Olavarria1, O Igoucheva2
¹,²Department of Dermatology and Cutaneous Biology, Thomas Jefferson University, Philadelphia, PA.
Congenital muscular dystrophies (CMD) are a clinically and genetically heterogeneous group of neuromuscular disorders characterized by muscle weakness within the first 2 years of life. The two most prevalent forms of CMD, i.e. collagen VI deficient CMD (COL6 CMD) and laminin α2 deficient CMD (LAMA2, MCD1A), are both caused by complete or partial deficiency in extracellular matrix (ECM) molecules. Patients with severe CMD manifestations can never walk independently and present with progressive respiratory function impairment, leading to early death. Currently, there is no effective treatment for this group of disabling and life-threatening disorders. Previous studies showed that cultured adult stem cells derived from adipose tissue synthesize and secrete all three collagen VI subunits and the laminin α2 chain. A significant obstacle in designing stem cell-based therapy for CMD and other muscular dystrophies is the necessity to reach the entire body musculature, and recent experimentation in this area shows poor cell recruitment to the muscle tissue. The key mechanism that regulates cell recruitment to distal anatomical sites and migration of cells inside affected tissue is chemotaxis, which depends on the signaling molecules termed chemokines. Here, we tested the novel hypothesis that unique chemotactic axes can be identified, based upon experimental observations of increased levels of chemokines in CMD-affected muscles, which can be useful in further research to enhance homing of stem cells from systemic compartment to CMD-affected muscles. Our observations of proteomic screens evaluating relevant skeletal muscle biopsies provided potential markers of disease activity and offered chemotactic axes to enhance directional migration of systemically transplanted cells into CMD-affected muscles.
3:30 PM: Ali Jubran-MSCB
The role of Integrin a5b1 receptor in Pharyngeal Arch Artery development. Ali Jubran, S Astrof1
1Center for Translational Medicine, TJU - 1020 Locust street, Philadelphia, PA 19107, USA
The development of the aortic arch arteries (AAAs) proceeds through a highly organized series of events during embryogenesis. It begins with the formation of the symmetrical pharyngeal arch arteries (PAAs) 3, 4, and 6, and culminates in their remodeling into the asymmetrical AAAs. Our lab discovered that the PAA endothelium is derived from the second heart field (SHF) mesoderm. The fate of SHF cells, their differentiation into endothelial cells, exit from the SHF, migration into the pharyngeal arches, and the assembly of endothelial cells into the PAAs is regulated by signaling from distinct tissues composing the pharyngeal arches: the endoderm, mesoderm, surface ectoderm, and the neural crest. Extracellular matrix (ECM) proteins and their integrin receptors are important regulators of intercellular and inter-tissue signaling. Our lab has demonstrated that the integrin a5b1 and its ECM ligand, fibronectin, play essential roles in AAA development. Conditional knockout of the Fn1 or integrin a5 genes in the Isl1 lineage, encompassing the SHF, pharyngeal arch endoderm, mesoderm, and the surface ectoderm, resulted in late embryonic/neonatal lethality due to AAA defects. Analyses of mutant embryos showed that the ablation of either Fn1 or integrin a5 in the Isl1 lineage resulted in defective formation of the 4th PAA. Our mutants display two interesting phenotypes: an endothelial cell deficiency in the 4th pharyngeal arch and defective assembly of endothelial cells into the 4th PAA. Our data suggest that the defective formation of the 4th PAA in our mutants is due to the altered balance between cell-cell and cell-ECM adhesion, resulting in defective migration of SHF-derived endothelial cells into the 4th pharyngeal arch.
Thursday, November 16, 2017
Location: Jefferson Alumni Hall, Room M61
1:00 PM: Jaclyn Hoover-MSPR
PHARMACOKINETIC AND BIODISTRIBUTION OF A NOVEL IgG-IgA Fc FUSION ANTIBODY VARIANT.
JM Hoover, SH Tam.
Janssen BioTherapeutics, Janssen R&D, LLC., Spring House, PA
As an alternative to conventional antibody therapeutics with an IgG Fc region, IgG -IgA Fc fusion molecules have been developed to elicit the effects of the IgA Fc region. Although IgA can engage distinct immune cells than IgG molecules, there are no FDA approved IgA therapeutics. To extend the therapeutic potential of IgG Fc molecules, IgG-IgA tandem Fc molecules were made. The pharmacokinetic (PK) and biodistribution profile were compared to corresponding IgA or IgG Fc molecules. Molecules were prepared to have the same anti-TNF Fab regions with different Fc regions comprising IgG, IgA, or tandem combinations of IgG-IgA (GGA) or IgA-IgG (GAG) and were tested in Tg32 hu FcRn transgenic (tg) mice and two strains of CD89 tg mice (Ly6 and UMC) along with their wild-type (WT) versions. Animals were injected intravenously with 125I labeled antibodies at 2 mg/kg, followed by serial bleeds from each animal for PK, and removal of organs at terminal time points for biodistribution. In Tg32 hu FcRn mice, the GAG construct had the longest PK with mean half-life for GAG (113 h) > GGA (58 h)> IgG (44 h) > IgA (20 h). Biodistribution results were consistent with these observations with greater tissue accumulation for GAG than the other molecules. Except for the longer half-life for IgG and GAG molecules in the Ly6 mice versus the UMC mice, all molecules had comparable PK and drug exposure (AUC) in the CD89 tg mice. In conclusion, the Fc fusion molecules, most notably with the GAG molecule, have a more desirable PK and greater retention in tissues than the IgA molecules whiling having better or similar profiles to the IgG molecules. Since both Ly6 and UMC mice have antibody PK and biodistribution profiles that are comparable to the WT mice, they can be potential rodent models for the IgA-IgG Fc molecules. These results support the potential of using IgA-IgG Fc fusion antibody design for future immunotherapeutics.
1:30 PM: Carol Lam-MSPR
ASSESSMENT OF RISK AND TRUST BASED DECISIONS IN PATIENTS ENTERING THE ONCOLOGY CLINICAL TRIAL RECRUITMENT PROCESS
C. Lam1 K. Connor1, J. Bruce Smith, MD1
1 Jefferson College of Biomedical Sciences
Cancer is listed as the second highest cause of death in the United States. These statistics present a crucial need for new cancer treatments. Clinical trials offer experimental treatments or a combination with standard treatments not yet approved by the FDA. Patients must provide their informed consent to enter these trials, but it has been suggested that patients may not fully understand the goals of the trial and give informed consent based on varying influences3. These influences may include physician recommendations or personal/familial sway. Such influences may have adverse consequences for the patient, for instance, the patient may be influenced to such a degree that they may disregard the risks of the trial. The goal of this study was to explore influencing factors on a patient in the informed consent process. We conducted a survey pilot study at one center targeting patients in the screening phase of an oncology clinical trial. Seven subjects participated in a 13-question survey. The survey asked the patients to rate their stance on trust-based questions. The data supports the suggestion that subjects who enrolled in oncology trials and their family/friends trust the institution and the research team. However, the data showed varying answers regarding future financial stability and the possible adverse effects of the trial. The subjects also displayed some altruism. However, this is a small pilot study; no formal conclusion can be made, but there is room for future research regarding these influences and the possible risks imposed.