Cancer Biology

Nicotinamide adenine dinucleotide (NAD⁺) is a coenzyme for many NAD⁺-consuming proteins with diverse biological functions. Oscillations in NAD⁺ levels may influence several cellular signaling pathways. NAD⁺ synthesis via Preiss-Handler route (salvage reactions) has been extensively reported. However, the contribution of L-tryptophan/kynurenine catabolism in de novo NAD⁺ synthesis is poorly understood. Using L-[14C]-tryptophan tracing in four liver cancer cell lines and siRNA-mediated silencing of arylformamidase (AFMID), a key enzyme involved in L-tryptophan degradation, we demonstrate the contribution of L-tryptophan catabolism in de novo synthesis of NAD⁺ pools. NAD⁺ modulation is therefore important in maintaining cellular homeostasis and appropriate cellular functions according to nutrients availability.

Vaccine-based immunotherapy is being used to treat dogs with primary brain tumors. The vaccines are composed of a lysate of autologous tumor cells, which stimulate an immune response producing tumor specific antibodies that are capable of inducing antibody-dependent cell-mediated cytotoxicity to allogeneic, as well as autologous, tumor cells. This protocol will describe the tumor cell serum antibody-binding assay to measure the tumor-reactive IgG antibody response. Key features of this assay are that it is performed with sera collected from the canine patient prior to and following vaccination as the source of antibodies and canine brain tumor cells used as the target cells.