Biology subjects

Ahn, B. Y.

Publications and source records attributed to Ahn, B. Y..

3 recordsLinked to original sources

bioRxiv2026

Eukaryotic Initiation Factor 5B (eIF5B)-Driven Translational Control Impacts Oral Squamous Cell Carcinoma Pathophysiology

The non-canonical translation of specific mRNAs has been implicated in oncogenesis and cancer progression. We previously identified eukaryotic Initiation Factor 5B (eIF5B) as a key factor in Internal Ribosome Entry Site (IRES)-mediated translation of a subset of mRNAs encoding anti-apoptotic proteins. Here, we demonstrate that EIF5B is predominantly expressed in cancer cells compared to other cell types in the Oral Squamous Cell Carcinoma (OSCC) microenvironment. Higher EIF5B mRNA and protein expression are associated with poor patient outcomes. We show that eIF5B depletion in OSCC cells blunted pro-growth, pro-inflammatory, and pro-angiogenic signaling pathways and significantly increased TNF-related apoptosis-inducing ligand (TRAIL)-induced cell death. This is achieved through decreased translation of mRNAs encoding critical factors associated with OSCC pathophysiology. Importantly, the level of interaction of eIF5B with tRNAiMet was significantly higher in OSCC cells compared to non-cancerous fibroblasts. This suggests that OSCC cells (but not non-cancerous fibroblasts) rely heavily on eIF5B for translation initiation. In an in vivo flank xenograft model using nude mice, eIF5B knockdown in UMSCC-29 cells led to a significant reduction in tumor volume compared to control tumors. Also, the immunohistochemical analysis of the xenografted tumor sections demonstrated decreased staining intensity of critical factors associated with OSCC pathophysiology in eIF5B-depleted tumors relative to controls. Collectively, our data demonstrate that OSCC cells are uniquely dependent on eIF5B-tRNA interactions to sustain translation of pro-survival mRNAs. Targeting eIF5B disrupts these oncogenic programs, sensitizing OSCC cells to apoptosis and suppressing pro-angiogenic and pro-growth signaling.

cancer biology↗

bioRxiv2025

Inhibitory Circuit Compensations in Female and Male Mice: Increased Synaptic Output Offsets Reduced Parvalbumin Interneuron Density

Parvalbumin inhibitory interneurons (PV-INs) are critical regulators of excitatory/inhibitory balance in the cortex, and their dysfunction has been observed in various neurological disorders. Despite increasing recognition of sex differences in brain function, little is known about how PV-INs differ between males and females under healthy conditions. Previous work has pointed to sex differences in PV-IN vulnerability in disease and injury models. Here, we investigated sex differences in PV-IN characteristics, connectivity, and function in the retrosplenial cortex (RSC) of healthy mice. We found that female mice have significantly fewer PV-INs in the RSC compared to males, yet exhibit comparable memory induced neuronal activation (fos expression). Despite their lower numbers, female PV-INs displayed greater synaptic connectivity, as evidenced by increased synaptotagmin-2 (Syt-2) puncta per PV-IN and higher axonal bouton density. Additionally, fewer female PV-INs were surrounded by perineuronal nets (PNNs), suggesting greater plasticity in female inhibitory networks. From ex vivo slice electrophysiology recordings we observed greater excitability in female PV-INs compared to male PV-INs and, a reduced incidence of IPSCs. These findings indicate that female mice may compensate for reduced PV-IN numbers through enhanced synaptic output, preserving inhibitory function in the RSC. Finally, using spatial transcriptomic profiling of PV-INs we observed a number of differentially expressed genes that are consistent with the observed structural and functional differences between female and male PV-INs. Understanding these sex-specific inhibitory mechanisms is crucial for developing more targeted interventions for conditions involving PV-IN impairment and for understanding sex specific vulnerabilities to certain conditions such as Alzheimers disease.

neuroscience↗

bioRxiv2023

Spatiotemporal modeling reveals high-resolution invasion states in glioblastoma

Diffuse invasion of glioblastoma cells through normal brain tissue is a key contributor to tumor aggressiveness, resistance to conventional therapies, and dismal prognosis in patients. A deeper understanding of how components of the tumor microenvironment (TME) contribute to overall tumor organization and to programs of invasion may reveal opportunities for improved therapeutic strategies. Towards this goal, we applied a novel computational workflow to a spatiotemporally profiled GBM xenograft cohort, leveraging the ability to distinguish human tumor from mouse TME to overcome previous limitations in analysis of diffuse invasion. Our analytic approach, based on unsupervised deconvolution, performs reference-free discovery of cell types and cell activities within the complete GBM ecosystem. We present a comprehensive catalogue of 15 tumor cell programs set within the spatiotemporal context of 90 mouse brain and TME cell types, cell activities, and anatomic structures. Distinct tumor programs related to invasion were aligned with routes of perivascular, white matter, and parenchymal invasion. Furthermore, sub-modules of genes serving as program network hubs were highly prognostic in GBM patients. The compendium of programs presented here provides a basis for rational targeting of tumor and/or TME components. We anticipate that our approach will facilitate an ecosystem-level understanding of immediate and long-term consequences of such perturbations, including identification of compensatory programs that will inform improved combinatorial therapies.

cancer biology↗