Biology subjects

Killarney, S. T.

Publications and source records attributed to Killarney, S. T..

3 recordsLinked to original sources

bioRxiv2026

Chromosomal instability and chromosome 17p loss drive convergentNDE1 synthetic lethality in metastatic cancer cells

Recent studies have identified recurrent features of metastatic cancer cells such as their increased chromosomal instability (CIN) and frequent loss of the short arm of chromosome 17 (Chr17p). However, it remains unclear whether these features induce synthetic lethal vulnerabilities that can be used to specifically target metastatic disease. Using whole-genome CRISPR/Cas9 loss-of-function screens performed in matched primary and CIN-high brain-metastatic tumor models, we discovered that brain-metastatic cells exhibit increased sensitivity to the loss of diverse regulators of chromosome segregation. Knockout of one such regulator, NDE1, selectively inhibited the growth of brain-metastatic models in vitro and in vivo, an effect driven by the loss of STAG2 and consequent induction of CIN. Surprisingly, dependence on NDE1 was also highly correlated with loss of Chr17p across hundreds of cancer cell lines in DepMap, the result of losing the NDE1 paralog NDEL1, which resides at this locus. CIN and Chr17p loss are thus independently sufficient to drive NDE1 dependence in brain-metastatic cells, and the presence of both features increases NDE1 dependence additively. These findings demonstrate that metastasis evolution endows cancer cells with specific vulnerabilities, including one that is driven by two recurrently altered molecular features of metastatic disease.

cancer biology↗

bioRxiv2025

Pathway Coessentiality Mapping Reveals Complex II is Required for de novo Purine Biosynthesis in Acute Myeloid Leukemia

Understanding how cellular pathways interact is crucial for treating complex diseases like cancer, yet our ability to map these connections systematically remains limited. Individual gene-gene interaction studies have provided insights1,2, but they miss the emergent properties of pathways working together. To address this challenge, we developed a multi-gene approach to pathway mapping and applied it to CRISPR data from the Cancer Dependency Map3. Our analysis of the electron transport chain revealed certain blood cancers, including acute myeloid leukemia (AML), depend on an unexpected link between Complex II and purine metabolism. Through stable isotope metabolomic tracing, we found that Complex II directly supports de novo purine biosynthesis and exogenous purines rescue AML from Complex II inhibition. The mechanism involves a metabolic circuit where glutamine provides nitrogen to build the purine ring, producing glutamate that Complex II must oxidize to sustain purine synthesis. This connection translated to a metabolic vulnerability whereby increasing intracellular glutamate levels suppresses purine production and sensitizes AML to Complex II inhibition. In mouse models, targeting Complex II triggered rapid disease regression and extended survival in aggressive AML. The clinical relevance of this pathway emerged in human studies, where higher Complex II gene expression correlates with both resistance to mitochondria-targeted therapies and worse survival outcomes specifically in AML patients. These findings establish Complex II as a central regulator of de novo purine biosynthesis and identify it as a promising therapeutic target in AML.

cancer biology↗

bioRxiv2023

MCB-613 exploits a collateral sensitivity in drug-resistant EGFR-mutant non-small cell lung cancer through covalent inhibition of KEAP1

Targeted therapies have revolutionized cancer chemotherapy. Unfortunately, most patients develop multifocal resistance to these drugs within a matter of months. Here, we used a high-throughput phenotypic small molecule screen to identify MCB-613 as a compound that selectively targets EGFR-mutant, EGFR inhibitor-resistant non-small cell lung cancer (NSCLC) cells harboring diverse resistance mechanisms. Subsequent proteomic and functional genomic screens involving MCB-613 identified its target in this context to be KEAP1, revealing that this gene is selectively essential in the setting of EGFR inhibitor resistance. In-depth molecular characterization demonstrated that (1) MCB-613 binds KEAP1 covalently; (2) a single molecule of MCB-613 is capable of bridging two KEAP1 monomers together; and, (3) this modification interferes with the degradation of canonical KEAP1 substrates such as NRF2. Surprisingly, NRF2 knockout sensitizes cells to MCB-613, suggesting that the drug functions through modulation of an alternative KEAP1 substrate. Together, these findings advance MCB-613 as a new tool for exploiting the selective essentiality of KEAP1 in drug-resistant, EGFR-mutant NSCLC cells.

cancer biology↗