Topoisomerase 2 (Top2) poisons are widely used in cancer therapy but are associated with toxicity and secondary malignancies. Top2 adduct removal requires endonuclease activity prior to repair of the resulting DNA double-strand break (DSB). We show that the non-homologous end joining (NHEJ) enzyme Artemis is a key player in the process and a major target for treatment of human B-cell acute lymphoblastic leukemia (ALL). An Artemis knockout is sensitive to etoposide treatment at nanomolar levels and has significantly more unrepaired DNA DSBs. Inhibition of the Artemis activator, DNA-dependent Protein Kinase Catalytic Subunit (DNA-PKcs), acts synergistically with Top2 poisons to further sensitize ALL cells. Genetic loss of Artemis ablates this synergy underscoring its critical role in this drug interaction. Furthermore, Artemis loss results in a significant accumulation of covalent Top2A DNA adducts following etoposide treatment and a significant increase in unrepaired DNA DSBs. As clinical data demonstrate that high Artemis expression correlates with poor survival in several cancers, our work may unlock new avenues for the treatment of aggressive cancers.
Melissa L. Folkerts, C. Hom, Angie Nguyen et al.· Communications Biology· 0 citations
Polyendocrine metabolic ovarian syndrome (PMOS), formerly known as polycystic ovary syndrome (PCOS), is the most common endocrine disorder in women and is closely associated with complex diseases such as cardiovascular disease and type 2 diabetes. However, the mechanistic links between PMOS and its comorbidities remain poorly understood. Here, we present an integrative systems genetics platform that leverages genetic diversity in both mice and humans to dissect the drivers of PMOS and its associated complications. This framework uncovers conserved genetic and environmental factors underlying PMOS, identifies susceptible cell types and organs, and elucidates mechanisms linking PMOS to subsequent pathologies. For instance, we show that increased ovarian area contributes to both PMOS susceptibility and ovarian cancer progression, while specific ovary-heart signaling circuits modulate cardiac function with aging. We further identify ovarian SF3B1-mediated alternative splicing as a key mechanistic link between PMOS and metabolic traits. Pharmacologic inhibition of SF3B1 in mice reduced circulating testosterone, insulin and glucose levels, as well as fat mass expansion. Transcriptomics analysis of ovaries from mice and experiments using human cell lines localized these effects to exon skipping events in granulosa cells. Together, this study offers a mechanistic framework for modeling the diversity of PMOS pathologies and uncovers SF3B1-mediated splicing as a link between ovary function and systemic metabolism.
Christy M. Nguyen, L. Velez, Youngseo Cheon et al.· Journal of Clinical Investig...· 0 citations