SUMMARY: UCLA researchers in the Department of Pediatrics have developed a means of utilizing the a biorthogonal sugar called cellobiose as a carbon source for T cells and other mammalian cells for widespread use including as an improved cell therapy platform. BACKGROUND: Cancerous tumors are well characterized to be highly metabolically active as they undergo rapid uncontrolled cell division. Glucose is the preferred carbon source for cellular metabolism during this process. This characteristic allows well-established diagnostic methods, including positron emission tomography (PET) scans, to identify tumors that sequester large amounts of radiolabeled glucose. Like healthy human tissue cells, tumor cells can naturally metabolize a small set of simple monosaccharide and disaccharide sugars, including glucose. Because of this overlap in bioavailable carbon sources, cancerous cells often starve nearby healthy tissue of nutrients to expand the tumor mass. This effect contributes to the harm tumors do to their surrounding environment and makes cell-based immunotherapy techniques challenging. In these cell-based therapies, where human lymphocytes are engineered to attack tumor cells, one strategy being investigated to offer cell therapies a competitive advantage over tumor cells is to engineer an orthogonal carbon source that can be metabolized by the engineered cytotoxic cells but is inert to cancer cells. In order to advance on this promising strategy, there is a need for the development of systems that can only feed cells used for cell therapy and is nonproductive for cancer cells. INNOVATION: UCLA researchers in the Department of Pediatrics have developed a means of utilizing the disaccharide sugar called cellobiose as a carbon source for T cells and other mammalian cells. Cellobiose is a disaccharide comprised of two glucose molecules connected by a bond that neither human, nor most bacterial, or fungal metabolic processes can naturally break, but is readily metabolized by an enzyme found in certain organisms that survive off plant matter. The research team engineered mammalian cells to express proteins that facilitate the import and metabolism of the sugar. This allows these cells to use native glycolysis to convert the glucose molecules from cellobiose into energy, whereas cells not engineered to have this function would be unable to produce the glucose derivative and starve. This system could therefore be applied to cell therapies in vivo: where therapeutic cells engineered to metabolize cellobiose could be introduced into patients along with cellobiose, thereby giving a metabolic advantage to the therapeutic cells over targeted malignant ones. Alternative applications include reducing the reliance on antibiotics and antifungal additives in cell culture, by culturing cells in the cellobiose media that cannot support undesired contaminants. Cellobiose, therefore, can be used as a biorthogonal carbon source during the growth of mammalian cells and use of cell therapies for widespread applications, including the treatment of tumors and infections, and other applications where low glucose diets are advantageous, including for treatment of seizures. POTENTIAL APPLICATIONS: • Cancer Immunotherapy • Pathogenic Infections • Other applications with low glucose intake diets. • Contaminant-free mammalian cell culture ADVANTAGES: • Cellobiose cannot natively be metabolized by tumor cells and normal human tissue cells. • Cellobiose is efficiently converted to glucose for metabolism in engineered cells. DEVELOPMENT-TO-DATE: UCLA researchers have demonstrated the effectiveness of cellobiose as an energy source for engineered T cells expressing the disaccharide importer and the glucosidase enzyme to metabolize cellobiose to glucose. The research group demonstrated that T cells expressing these effectively make use of cellobiose in glucose-starved environments.