Project 3: Targeting Tumor Metabolism in Lymphoma

ABSTRACT: Project 3. A key feature of lymphomas is the glucose hypermetabolism visualized on FDG-PET imaging. In Project 3 (P3), we are investigating two novel drivers of glucose uptake and utilization. Our preliminary data have revealed that abnormal glucose uptake is a striking feature of B cells deficient in the signaling adaptor protein, TNFR-associated factor 3 (TRAF3). Indeed, ~30% of DLBCL samples have histologic evidence of TRAF3 deficiency. We also found that the multi-functional glycogen synthase kinase (GSK3) is increased in lymphoma cells. B cell TRAF3 in the nucleus promotes the degradation of the cAMP response element-binding protein (CREB) transcriptional complex, and the CREB pro-survival targets Mcl-1, Pim2, and c-Myc are elevated in TRAF3-deficient B cells. In addition, the CREB and NF-?B2 targets Glut1 and hexokinase 2 (HXK2) are also elevated in TRAF3-deficient B cells (as is glucose metabolism) and these cells have increased GSK3 expression. Interfering with GSK3 either by GSK3?/? knockouts that we developed or by inhibiting the GSK3 with a novel inhibitor 9ING-41 (Actuate Therapeutics) inhibits cell proliferation and induces apoptosis while sparing normal lymphocytes. Thus, there is an important link between the TRAF3 and GSK3 pathways that can potentially be exploited for therapeutic benefit. The overall hypothesis of P3 is that targeting the hyperactive metabolic pathways induced by dysregulation of key signaling pathways in lymphoma cells (TRAF3 deficiency; GSK3 hyperactivity) will provide a new approach to treatment that will enhance established therapies. We have organized this work into 3 Specific Aims. Aim 1. Determine how TRAF3 deficiency regulates survival and glucose metabolism in pre-malignant and malignant B cells. Aim 2: Determine the mechanism of action of GSK3 inhibitors in lymphoma cells to develop rational combinations for clinical trials. Aim 3: Conduct clinical trials of novel inhibitors of tumor metabolism in patients with relapsed lymphoma. P3 is addressing a significant unmet need in lymphoma biology and therapeutics ? understanding and targeting the pathways and mechanisms of the increased glucose metabolism that characterizes almost all aggressive lymphomas at diagnosis and those tumors that fail initial therapy and become refractory. We are approaching this problem in lymphoma biology and treatment with a team experienced in the study of lymphoma biology, signal transduction pathway analysis and clinical trials experience with signal transduction pathway inhibitors. Within the 5 years of this Project we aim to translate new biomarkers and therapies to our patients with glucose-avid lymphomas and spur new research into this important area.