| Summary: | Part 1: The most frequently mutated gene in human cancer is the tumor suppressor gene p53, which is routinely found to have missense mutations at recurrent hotspot residues. Investigations of mutant p53 hotspot variants have suggested novel gain-of-function (GOF) traits, which can be driven through mutant-specific protein-protein interactions. In order to investigate possible drivers of GOF phenotypes, we used the protein proximity labeling assay BioID to interrogate differences between wild-type and point mutant p53 interactomes. We demonstrate that p53 retains function after addition of the biotin ligase miniTurbo and that known p53 binders can be identified. We further characterize the interactomes of 4 p53 hotspot mutants (R172H, R245Q, R245W & 270H) and reveal numerous examples of mutant- specific binding partners, including potential pan-mutant interactors. We also validated the increased interaction between p53 R172H and the chaperonin CCT8. Further investigation to validate mutant-specific and pan-mutant binding partners found in this study could unlock a plethora of potential new treatments for cancers harboring p53 point mutants.
Part 2: While there has long been speculation that the immune system can recognize and kill tumor cells, recent developments in immunotherapy have truly transformed cancer treatments. Although some patients who receive immunotherapy have durable responses, and even cures, a significant subset of patients do not respond, illustrating the need for improved immunotherapies and a better understanding of what drives the differences seen in patients. In this work, we describe the development of a novel method for investigating natural killer (NK) cell responses in autochthonous models of lung cancer, using lentiviral vectors that initiate tumors and express the NK cell ligand, m157. Using this model, we demonstrate that NK cells become rapidly dysfunctional during tumor progression, but can be stimulated to regain function. We additionally reveal that activation of NK cells in the tumor microenvironment results in increased recruitment and infiltration of adaptive immune cells. This work suggests that modulating NK cell responses may improve the efficacy of T cell immunotherapies.
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