Biology subjects

Subramaniyan, B.

Publications and source records attributed to Subramaniyan, B..

3 recordsLinked to original sources

bioRxiv2025

Loss of the Y chromosome drives cancer metabolic reprogramming

Metabolic reprogramming promotes cancer aggressiveness and an immune-suppressive tumor microenvironment. Loss of the Y chromosome (LOY) drives both phenotypes in bladder cancer (BC). We investigated the hypothesis that LOY leads to metabolic reprogramming using untargeted metabolomic profiling of human BC cells and analysis of pan-cancer transcriptomic datasets. This revealed that aerobic glycolysis is activated in LOY BC cells. Since prior work showed that expression of collagen receptor DDR2 drives BC progression and DDR2 is a regulator of tumor metabolism, we investigated if DDR2 is implicated in metabolic reprogramming of LOY-tumors. Analysis of scRNAseq data from 251 patients with 12 tumor types found that LOY and DDR2 expression promote aerobic glycolysis, and this was confirmed by metabolomics. Deletion of DDR2 in LOY BC cells reduced glycolytic flux, inhibited cell proliferation, reduced EMT and stemness features, and promoted apoptosis. Our data provide a rationale for using LOY as a tumor selection biomarker for DDR2 targeted therapeutics. TeaserLoss of the Y chromosome augments glycolytic metabolism in bladder cancer cells, and this is in part dependent on the collagen receptor DDR2.

cancer biology↗

bioRxiv2025

Pyrimethamine inhibits mutant NRF2 as a molecular glue

Esophageal squamous cell carcinoma (ESCC) is a deadly disease and one of the most aggressive cancers of the gastrointestinal tract. As a master transcription factor regulating the stress response, nuclear factor erythroid 2-related factor 2 (NRF2) is often mutated, loses negative regulation by Kelch-like ECH-associated protein 1 (KEAP1), becomes hyperactive, and thus causes chemo-radioresistance and poor survival in human ESCC. Our previous research identified pyrimethamine (PYR) as an NRF2 inhibitor and demonstrated that inhibition of dihydrofolate reductase (DHFR) is the major mechanism of its action. Based on these findings, PYR has advanced into a Phase I window-of-opportunity clinical trial. In this study, using isogenic ESCC cell lines, we aimed to investigate the phenotypic consequences of NRF2 activation in ESCC cells and further elucidate the mechanism of action of PYR. While overexpression of wild-type NRF2 (NRF2WT) promoted squamous differentiation and suppressed proliferation, expression of mutant NRF2 (NRF2Mut) produced mixed effects on differentiation markers and promoted proliferation. NRF2 activation reduced sensitivity to chemotherapy and radiation, whereas PYR treatment restored chemosensitivity and radiosensitivity in NRF2Mut ESCC cells. Co-immunoprecipitation and proximity ligation assays revealed that PYR selectively enhanced the interaction between NRF2W24C and KEAP1, but not between NRF2WT and KEAP1. Isothermal titration calorimetry (ITC) confirmed the direct binding of PYR to KEAP1 and surface plasmon resonance (SPR) showed that PYR modestly facilitated the interaction between a DLGW24C peptide and the Kelch fragment. Molecular docking suggested that PYR bound to a pocket within the Kelch domain near Arg415. In summary, NRF2 activation promotes cell proliferation and therapy resistance in ESCC in a context-dependent manner. PYR functions as a modest molecular glue that selectively restores KEAP1 binding to NRF2W24C, providing a potential therapeutic strategy for NRF2Mut ESCC.

cancer biology↗

bioRxiv2021

The NOTCH3 Downstream Target HEYL Regulates Human Airway Epithelial Club Cell Differentiation

Basal cells (BC) are the resident stem/progenitor cells of the adult pseudostratified airway epithelium, whose differentiation program is orchestrated by the NOTCH signaling pathway. NOTCH3 receptor mediated signaling regulates BC to club cell differentiation; however, the downstream responses that regulate this process are largely unknown. In the present study we used an in vitro air-liquid interface model of the human pseudostratified airway epithelium to identify the NOTCH3-dependent downstream genes/pathways that regulate human BC to club cell differentiation. Activation of NOTCH3 signaling in BC via lentivirus-mediated over-expression of the active NOTCH3 intracellular domain (NICD3) promoted club cell differentiation. Bulk RNA-seq analysis of control vs NICD3-transduced cells, identified 692 NICD3 responsive genes enriched for pathways linked to airway epithelial biology and differentiation including Wnt/{beta}-catenin Signaling. Expression of the classical NOTCH target HEYL increased in response to NOTCH3 activation and positively correlated with expression of the club cell marker SCGB1A1. Further, using single-cell RNA-seq, we report that HEYL+ cells primarily clustered with SCGB1A1+ and NOTCH3+ cells. Moreover, HEYL protein co-localized with SCGB1A1 in ALI cultures in vitro and in the human and mouse airway epithelium in vivo. siRNA-mediated knockdown of HEYL in BC led to changes in epithelial structure including altered morphology and significant reductions in transepithelial electrical resistance and expression of tight junction related genes. Finally, HEYL knockdown significantly reduced the number of SCGB1A1+ club cells, along with a corresponding increase in KRT8+ BC-intermediate cells. Overall, our data identifies NOTCH3-HEYL signaling as a key regulator of BC to club cell differentiation.

cell biology↗