Biology subjects

Fujihara, K.

Publications and source records attributed to Fujihara, K..

3 recordsLinked to original sources

bioRxiv2025

Targeting DNA Polymerase Epsilon Leads to Tumor Clearance and Activation of an NF-κB mediated inflammatory response in Triple Negative Breast Cancer

Breast cancer remains the second leading cause of cancer-related mortality among women, with triple-negative breast cancer (TNBC) exhibiting a particularly poor five-year prognosis1. Here, we demonstrate that among genetic and pharmacological perturbations targeting DNA replication, suppression of DNA polymerase epsilon (POLE) in TNBC, induces a potent, TNBC-specific gene expression signature enriched in inflammatory cytokines that are transcriptional targets of NF-{kappa}B. TNBC cells exhibit markedly higher levels of DNA damage and canonical NF-{kappa}B activation compared to luminal breast cancer cells. Notably, NF-{kappa}B activation in this context depends on the canonical component RELA, but not the non-canonical component RELB. Mechanistically, ATM, STING, and RIG-I each contribute to NF-{kappa}B activation following POLE suppression. In vivo, POLE suppression in a murine TNBC model leads to cancer cell-intrinsic elimination of tumor burden and increased immune cell infiltration. Together, these findings support a model in which replication stress from POLE inhibition triggers robust NF-{kappa}B-mediated inflammation and immune microenvironment remodeling in TNBC and can independently trigger tumor eradication. These results suggest a potential therapeutic avenue for targeting POLE in TNBC.

cancer biology↗

bioRxiv2021

High-content profiling reveals a unified model of copper ionophore dependent cell death in oesophageal adenocarcinoma

Background and AimsOesophageal adenocarcinoma (OAC) is of increasing global concern due to increasing incidence, a lack of effective treatments, and poor prognosis. Therapeutic target discovery and clinical trials have been hindered by the heterogeneity of the disease, lack of driver mutations, and the dominance of large-scale genomic rearrangements. In this work we have characterised three potent and selective hit compounds identified in an innovative high-content phenotypic screening assay. The three hits include two approved drugs; elesclomol and disulfiram, and another small molecule compound, ammonium pyrrolidinedithiocarbamate. We uncover their mechanism of action, discover a targetable vulnerability, and gain insight into drug sensitivity for biomarker-based clinical trials in OAC. MethodsElesclomol, disulfiram, and ammonium pyrrolidinedithiocarbamate were systematically characterised across panels of oesophageal cell lines and patient-derived organoids. Drug treated oesophageal cell lines were morphologically profiled using a high-content, imaging platform. Compounds were assessed for efficacy across patient-derived organoids. Metabolomics and transcriptomics were assessed for the identification of oesophageal-cancer specific drug mechanisms and patient stratification hypotheses. ResultsHigh-content profiling revealed that all three compounds were highly selective for OAC over tissue-matched controls. Comparison of gene expression and morphological signatures unveiled a unified mechanism of action involving the accumulation of copper selectively in cancer cells, leading to dysregulation of proteostasis and cancer cell death. Basal omic analyses revealed proteasome and metabolic markers of drug sensitivity, forming the basis for biomarker-based clinical trials in OAC. ConclusionsIntegrated analysis of high-content imaging, transcriptomic and metabolomic data has revealed a new therapeutic mechanism for the treatment of OAC and represents an alternative target-agnostic drug discovery strategy.

cancer biology↗

bioRxiv2020

The TIM22 complex regulates mitochondrial one-carbon metabolism by mediating the import of Sideroflexins

The Acylglycerol Kinase (AGK) is a mitochondrial lipid kinase that contributes to protein biogenesis as a subunit of the TIM22 complex at the inner mitochondrial membrane. Mutations in AGK cause Sengers syndrome, an autosomal recessive condition characterized by congenital cataracts, hypertrophic cardiomyopathy, skeletal myopathy and lactic acidosis. We undertook proteomic profiling of Sengers patient fibroblasts and an AGKKO cell line to map the proteomic changes that ensue upon AGK dysfunction. This uncovered extensive remodelling of mitochondrial one-carbon metabolism enzymes and showed that inner membrane serine transporters, Sideroflexins (SFXNs), are novel substrates of the TIM22 complex. Deletion of SFXN1 recapitulates the remodelling of one-carbon metabolism observed in Sengers patient cells. Proliferation of cells lacking AGK is perturbed in the absence of exogenous serine and rescuable through addition of formate, highlighting the dysregulation of one carbon metabolism as a key molecular feature in the biology of Sengers syndrome.

cell biology↗