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Biomedical subjects

Kris C Wood

Publications and source records attributed to Kris C Wood.

5 recordsLinked to original sources

FANCM is required for the PAX3::FOXO1-driven oncogenic program in rhabdomyosarcoma.

Many cancers are driven by mutationally altered transcription factors (TFs) that rewire cells to an oncogenic state. Cells must activate specific mechanisms to tolerate the burden of oncogenic TF activity. To define such mechanisms, we focused on a canonical oncogenic fusion protein-driven cancer, alveolar rhabdomyosarcoma (ARMS), where the PAX3::FOXO1 fusion protein hyperactivates and mislocalizes PAX3 and FOXO1 TF functions. Employing sequential functional genomic CRISPR-Cas9 screens, we identified FANCM, a DNA translocase in the Fanconi anemia pathway, as a selective dependency in PAX3::FOXO1+ ARMS. FANCM loss reduces fusion protein levels, induces myogenic differentiation, and disrupts the PAX3::FOXO1 transcriptional program, thereby halting oncogenic proliferation. Mechanistically, FANCM depletion exacerbates replication stress (RS) and DNA damage signaling, with chromatin-associated RS enriched at PAX3::FOXO1 target gene loci, resulting in selective downregulation of the oncogenic program. CRISPR exon-tiling screens prioritized FANCM's helicase and DNA-binding domains as essential for this dependency, linking FANCM-mediated replication fork binding to sustained oncogenesis.

ARMS↗

BRCA1-A and LIG4 complexes mediate ecDNA biogenesis and cancer drug resistance.

Extrachromosomal circular DNA (ecDNA) is frequently generated within the nucleus, contributing to genome dynamics and heterogeneity, thereby promoting cancer cell evolution and adaptation. However, the mechanisms underlying ecDNA biogenesis remain poorly understood. Here, using genome-wide CRISPR screening in human cells, we identified the BRCA1-A and the LIG4 complexes as key drivers of ecDNA production. Following DNA segmentation, the upstream BRCA1-A complex protects DNA ends from excessive resection, promoting end-joining for circularization. Conversely, the MRN complex, which mediates end resection and thus antagonizes the BRCA1-A complex, suppresses ecDNA formation. Downstream, LIG4 conservatively mediates ecDNA production by joining the free ends of the DNA fragments. Furthermore, ecDNA from patient tumors harbors junction sites with a LIG4 signature. Notably, disruption of either LIG4 or the BRCA1-A complex in cancer cells impairs ecDNA-mediated adaptation, hindering the development of resistance to both chemotherapy and targeted therapies. Together, our study reveals the roles of the LIG4 and BRCA1-A complexes in ecDNA biogenesis, and uncovers therapeutic targets to block ecDNA-mediated adaptation for cancer treatment.

Humans↗

Controlling interlayer diffusion to achieve sustained, multiagent delivery from layer-by-layer thin films.

We present the fabrication of conformal, hydrolytically degradable thin films capable of administering sustained, multiagent release profiles. Films are constructed one molecular layer at a time by using the layer-by-layer, directed-deposition technique; the subsequent hydrolytic surface erosion of these systems results in the release of incorporated materials in a sequence that reflects their relative positions in the film. The position of each species is determined by its ability to diffuse throughout the film architecture, and, as such, the major focus of this work is to define strategies that physically block interlayer diffusion during assembly to create multicomponent, stratified films. By using a series of radiolabeled polyelectrolytes as experimental probes, we show that covalently crosslinked barriers can effectively block interlayer diffusion, leading to compartmentalized structures, although even very large numbers of ionically crosslinked (degradable or nondegradable) barrier layers cannot block interlayer diffusion. By using these principles, we designed degradable films capable of extended release as well as both parallel and serial multiagent release. The ability to fabricate multicomponent thin films with nanoscale resolution may lead to a host of new materials and applications.

Journal Article↗

Tunable drug release from hydrolytically degradable layer-by-layer thin films.

The development of new thin film fabrication techniques that allow for precise control of degradation and drug release properties could represent an important advance in the fields of drug delivery and biomedicine. Polyelectrolyte layer-by-layer (LBL) thin films can be assembled with nanometer scale control over spatial architecture and morphology, yet very little work has focused on the deconstruction of these ordered thin films for controlled release applications. In this study, hydrolytically degradable LBL thin films are constructed by alternately depositing a degradable poly(beta-amino ester) (polymer 1) and a series of model therapeutic polysaccharides (heparin, low molecular weight heparin, and chondroitin sulfate). These films exhibit pH-dependent, pseudo-first-order degradation and release behavior. The highly versatile and tunable properties of these materials make them exciting candidates for the controlled release of a wide spectrum of therapeutics.

Journal Article↗