Mechanisms of Endogenous DNA Damage Promotion

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Mechanisms of Endogenous DNA Damage Promotion Identification of the oncogenic mechanisms underlying cancer-promoting mutations remains a critical bottleneck in translation of discovered cancer-gene identities into effective anti-cancer strategies. Furthermore, strong correlations of Alzheimer’s disease (AD) with cancers indicate that these mechanisms also underlie AD. Their identification may allow fundamentally new AD pre-disease biomarkers, diagnostic, preventative and possibly therapeutic strategies. The goal of this multi-PI project is to leverage the team’s discovery in Escherichia coli, and its immediate translation to human homologs, of large, diverse, conserved networks of proteins that promote endogenous DNA damage and genome instability when overproduced—the DNA “Damage-up” Proteins (DDPs). DDP identities and mechanisms discovered indicate that many known and unknown overproduced oncoproteins are likely to constitute oncogenic and AD-associated mechanisms in which pathologies arise from destabilization of genomes rather than via the proteins’ other specific cell-biological functions. A network of E. coli DDPs promote endogenous DNA damage and mutation when overproduced, modeling many overproduction oncoproteins. The human homologs are highly enriched among known cancer driving genes, and their RNAs in cancers predict heavy tumor mutation loads and poor patient outcomes. 46% of human homologs sampled promote DNA damage and mutagenesis when overproduced in human cells, demonstrating the power of the E. coli platform for predicting human functions. Unlike genome instability and cancer caused by DNA-repair gene loss-of-function mutations, DDPs promote genome instability as gain-of-function alterations (overproduction), and so potentially can be drugged. DDPs defy previous cancer-gene/protein functional classes because they destabilize genomes but are not DNA-repair genes that suppress mutation rate, but instead are instigators of endogenous DNA damage and genome instability via mechanisms previously poorly defined. This project is aimed at revealing fundamental conserved mechanisms and consequences of endogenous DNA-damage promotion by DDPs using the E. coli model to guide cancer-protein function discovery in human cells. Because the DDPs and their activites are a new and innovative conceptual paradigm, we expect results of this project to re-direct many ongoing efforts in cancer prevention, diagnosis, and treatment. Because vast numbers and kinds of proteins are implicated, and cancer is strongly correlated with AD, increased endogenous DNA damage may be a widespread biomarker for cancer and AD susceptibility.