Neutralizing oxidative damage at telomeres prevents T cell dysfunction and improves adoptive cell therapies against cancer - PROJECT SUMMARY/ABSTRACT The remarkable success of immunotherapies has transformed the field of cancer therapeutics. Despite the clinical efficacy observed, most cancer patients will not experience a durable response from these therapies. Several intratumoral mechanisms have been described as key drivers for therapeutic resistance. In the case of adoptive cell therapies (ACTs), therapeutic failure is associated with insufficient persistence within the patient, inability to infiltrate tumors sites, and cell intrinsic loss of functionality. Our lab and others have highlighted how the metabolic landscape of the tumor microenvironment can impact the anti-tumor immune response and how metabolic reprogramming provides an opportunity to improve immune function. One of the most prevalent metabolic barriers in the TME is the accumulation of Reactive Oxidative Species (ROS). ROS accumulation in the tumor microenvironment (TME) has detrimental effects on T cell function and anti-tumor response, although the precise targets of ROS are unclear. Increasing evidence shows that mitochondrial ROS can profoundly affect telomere status and integrity in cells. However, little is known about how oxidative stress impacts telomere function in immune cells. Our preliminary data demonstrates an accumulation of telomeric DNA damage in tumor infiltrating lymphocytes from mouse and human melanoma samples shown by the presence of DNA damage response elements 53BP1 and ƔH2AX at telomeres. Our data show that telomeric ROS causes the accumulation of DNA damage at telomeres, as well as the development of telomere fragility. These cells ultimately become dysfunctional showing a diminished capability for cytokine production. We tethered the antioxidant protein GPX1 to TRF1 to generate a telomere-guided ROS scavenger. Localizing the ROS scavenger GPX1 directly to telomeres reduced telomere fragility and improved the function of therapeutic T cells in a mouse melanoma model. In this proposal we will determine how mitigating oxidative stress at telomeres can improve T cell function in an adoptive cell therapy model and translate these findings into a human CAR T cell model. Aim1: With the use of mouse models, we will determine mechanistically the role of oxidative damage at telomeres on T cell function and how protecting telomeres with the ROS scavenger GPX1 can improve T cell anti-tumor activity during ACTs. Aim2: Determine the presence of telomere damage in human CAR-T cells after tumor infiltration and restore T cells function by mitigating ROS-induced damage at telomers. Given the challenges observed with current immunotherapies, particularly ACTs against solid tumors, it is imperative to understand how metabolic pressures such as ROS accumulation impact anti-tumor T cell function. Our goal is to reveal mechanisms by which telomere damage affects the activity, differentiation, and efficacy of T cells in the TME, potentially shedding light on strategies to metabolically improve cellular therapies for all cancer patients.
