Biology subjects

Balamurugan, K.

Publications and source records attributed to Balamurugan, K..

6 recordsLinked to original sources

bioRxiv2026

Metabolic maintenance of breast cancer cells and metastases throughE-cadherin/YAP-dependent pyruvate carboxylase expression

Epithelial-mesenchymal transition (EMT) and glycolytic metabolism are well-characterized drivers of cancer progression and metastasis. However, most primary breast tumors and metastases express E-cadherin and the epithelial phenotype is associated with mitochondrial oxidative metabolism, yet the causality and relevance of these relationships and their underlying mechanisms remain poorly understood. Using a 3D culture model with mechano-stimulation, we found that E-cadherin promotes mitochondrial oxidative phosphorylation (OXPHOS) while reducing oxidative stress. Through pharmacological and genetic manipulations of inflammatory breast cancer (IBC) and/or triple negative breast cancer (TNBC) cell lines, we identified pyruvate carboxylase (PC) as an E-cadherin effector. Critically, restoring PC in E-cadherin-silenced cells rescued mitochondrial oxygen consumption and protection from oxidative stress. Co-expression of E-cadherin and PC was confirmed in breast cancer tissues and experimental lung metastases. Mechanistically, E-cadherin induced PC expression and OXPHOS via AKT-mediated activation of YAP/ /TEAD transcription factors, which are better known as supporting EMT. Clinically relevant AKT and TEAD inhibitors reduced both PC expression and oxidative respiration. Importantly, PC inhibition as monotherapy attenuated established experimental lung metastases and primary tumor burden in mice. Taken together, these findings reveal that E-cadherin-mediated cell-cell adhesions directly support mitochondrial metabolism through AKT-YAP/TEAD-PC signaling, identifying a therapeutic vulnerability in metastatic epithelial TNBC.

cancer biology↗

bioRxiv2025

Assessment of Imaging Mass Cytometry (IMC) as a Tool to Characterize Circulating Tumor Cells (CTCs) in Preclinical Mouse Models

Circulating tumor cells (CTCs), particularly multicellular clusters, are associated with poor prognosis and may provide insight into mechanisms of metastasis and therapy resistance. Unbiased approaches for functionally characterizing CTCs in liquid biopsies are therefore urgently needed. Here, we evaluate multiplex imaging mass cytometry (IMC) for CTC analysis in mice bearing human xenograft tumors. In a single-step workflow, IMC uses metal-conjugated antibodies to simultaneously detect numerous proteins and post-translational modifications in minimally processed, small-volume blood samples collected from the tail vein or heart. Using breast cancer cell lines and a patient-derived xenograft (PDX), we assessed a panel of antibodies, including human-specific markers such as Lamin B1 (LMNB1), to enable cross-species interpretation. Combined with manual review, HALO AI-based cell segmentation was used to identify CTCs and quantify marker expression. This approach enables studies of how genetic and pharmacologic interventions alter the properties of single CTCs and CTC clusters in tumor-bearing mice.

cancer biology↗

bioRxiv2025

A simple liquid 3D cell culture paradigm models oxidative mitochondrial metabolism of epithelial breast cancer cells with relevance for lung metastases.

Three-dimensional (3D) cell culture systems have emerged as powerful tools for modeling tumor biology in ex vivo settings. However, the diverse array of available 3D culture methods presents challenges in selecting the most appropriate model for specific research questions. This study provides a comparative analysis of breast cancer cells (SUM149, IBC-3, and MDA-MB-468) in the mammosphere culture (SphC) model or an "emboli" culture (EmC) model, which enrich for cancer stem cells and epithelial features, respectively. The EmC model, designed originally for inflammatory breast cancer, is characterized by media viscosity and mechanical rocking of the culture vessel. Notably, cells in EmC showed a distinct and durable reduction in cell proliferation ex vivo while demonstrating increased capacity to establish experimental lung metastases in vivo. Ultrastructural quantitative analysis of electron microscopy images suggested that cells in EmC acquire nuclear and mitochondrial features that resemble those of tumor tissue. Proteomics, single-cell transcriptomics, and metabolic flux analyses showed that cells in EmC and SphC favor mitochondrial oxidative metabolism (OXPHOS) and glycolysis, respectively. EmC rendered cells hypersensitive to OXPHOS inhibition, but more resistant to oxidative stress. Several genes associated with lung metastasis, including ID1, were specifically enriched in EmC. Given the emerging role of OXPHOS in cancer cell survival during dissemination and as established metastases, we propose that the EmC paradigm is a suitable ex vivo model to study signaling pathways relevant for tumor tissue and to assess drug sensitivities and resistance mechanisms of metastatic breast cancer cells ex vivo. SIGNIFICANCEThis study provides an in-depth characterization of a resource-efficient yet powerful 3D culture paradigm to improve the physiological relevance of ex vivo approaches. Applicable to epithelial cancers, this model offers a platform to accelerate the discovery of physiologically relevant signaling pathways and specific cancer cell vulnerabilities.

cancer biology↗

bioRxiv2023

SARS-CoV-2 Nsp13 is a viral RHIM protein promoting cell death linked to Z-RNA sensing and ZBP1-RIPK3 signaling

RHIM is a protein motif in cell death proteins that assembles higher-order signaling complexes and triggers regulated cell death, which in itself limits virus spread and additionally triggers inflammation for mounting immune responses. A few DNA viruses employ viral RHIMs mimicking host RHIMs. However, these viral RHIMs counteract host cell death by interacting with host RHIM proteins and blocking complex formation to alleviate antiviral defenses. Whether RNA viruses operate such viral RHIMs remains unknown. RHIM-protein signaling promotes lung damage and cytokine storm in respiratory RNA virus infections, arguing the presence of viral RHIMs. Here, we report the novel viral RHIMs in Nsp13 and Nsp14 of SARS-CoV-2 and other bat RNA viruses, providing the basis for bats as the hosts for their evolution. Nsp13 promoted cell death in bat and human cells, however, viral RHIM of Nsp13 is more critical for human cell death than bat cells, suggesting species-specific regulation. The conformation of RNA-binding channel in Nsp13 is critical for cell death in bat and human cells. Nsp13 showed RHIM-dependent interactions with ZBP1 and RIPK3 and promoted the formation of large insoluble complexes of ZBP1 and RIPK3. Also, Nsp13 promoted ZBP1-RIPK3 signaling-mediated cell death dependent on intracellular RNA ligands. Intriguingly, the SARS-CoV-2 genome consists of bona fide Z-RNA-forming segments. These SARS-CoV-2 Z-RNA segments promoted Nsp13-dependent cell death, further revealing Nsp13s association with Z-RNA sensing and ZBP1-RIPK3 signaling. Our findings reveal the functional viral RHIMs of bat-originated RNA viruses regulating host cell death associated with Z-RNA sensing and ZBP1-RIPK3 signaling activation. These observations allow the understanding of mechanisms of cellular damage and cytokine storm in SARS-CoV-2 and other bat-originated RNA virus infections. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=144 SRC="FIGDIR/small/554434v2_ufig1.gif" ALT="Figure 1"> View larger version (52K): org.highwire.dtl.DTLVardef@f71c5aorg.highwire.dtl.DTLVardef@1666aa5org.highwire.dtl.DTLVardef@e37d82org.highwire.dtl.DTLVardef@145020f_HPS_FORMAT_FIGEXP M_FIG C_FIG One-sentence summaryBat-associated RNA viruses employ viral RHIMs and regulate host cell death.

immunology↗

bioRxiv2022

Stabilization of E-cadherin adhesions by COX-2/GSK3β signaling is a targetable pathway in metastatic breast cancer

Metastatic progression and treatment-resistance of breast cancer has been associated with epithelial-mesenchymal-transition including downregulation of E-cadherin (CDH1) expression, which can be initiated by inflammatory mediators such as COX-2. Recently, E-cadherin-mediated, cluster-based metastasis and treatment resistance has become more appreciated, though the mechanisms that maintain E-cadherin expression in this context are unknown. Through studies of inflammatory breast cancer and an in vitro tumor cell emboli culture paradigm, we identified a role for COX-2, a target gene of C/EBP{delta}, or its metabolite PGE2 in promoting protein stability of E-cadherin, {beta}-catenin and p120 catenin through inhibition of GSK3{beta}, without affecting CDH1 mRNA. The COX-2 inhibitor celecoxib downregulated E-cadherin complex proteins and caused cell death. Co-expression of E-cadherin and COX-2 was seen in breast cancer patients with poor outcome and, along with inhibitory GSK3{beta} phosphorylation, in patient-derived xenografts of triple negative breast cancer. Celecoxib alone decreased E-cadherin protein expression within xenograft tumors, reduced circulating tumor cells and clusters, and in combination with paclitaxel attenuated or regressed lung metastases. This study uncovered a mechanism by which metastatic breast cancer cells can maintain E-cadherin-mediated cell-cell adhesions and cell survival, suggesting that patients with COX-2+/E-cadherin+ breast cancer may benefit from targeting of the PGE2 signaling pathway.

cancer biology↗

bioRxiv2019

Proteomic analysis of Caenorhabditis elegans against S. Typhi toxic proteins

Background & AimsBacterial effector molecules are the crucial infectious agents and are sufficient to cause pathogenesis. In the present study, pathogenesis of S. Typhi toxic proteins on the model host Caenorhabditis elegans was investigated by exploring the host regulatory proteins during infection through quantitative proteomics approach. MethodsIn this regard, the host proteome was analysed using two-dimensional gel electrophoresis (2D-GE) and differentially regulated proteins were identified using MALDI TOF/TOF/MS analysis. Out of the 150 regulated proteins identified, 95 proteins were appeared to be downregulated while 55 were upregulated. Interaction network for regulated proteins was predicted using STRING tool. ResultsMost of the downregulated proteins were found to be involved in muscle contraction, locomotion, energy hydrolysis, lipid synthesis, serine/threonine kinase activity, oxidoreductase activity and protein unfolding and upregulated proteins were found to be involved in oxidative stress pathways. Hence, cellular stress generated by S. Typhi proteome on the model host was determined using lipid peroxidation, oxidant and antioxidant assays. In addition to that the candidate proteins resulted from the host proteome analysis were validated by Western blotting and roles of several crucial molecular players were analyzed in vivo using wild type and mutant C. elegans. ConclusionsTo the best of our knowledge, this is the first study to report the protein regulation in host C. elegans during S. Typhi toxic proteins exposure which highlights the significance of p38 MAPK and JNK immune pathways. These results may provide new clues for future therapeutic approaches for curing bacterial toxin protein-mediated infections in a host system. SummaryWe have precipitated the toxin proteins of S.Typhi. To gain insight into the worms response to ingestion of toxin, a proteomic analysis was performed to monitor the changes in protein regulation. 150 differential regulated proteins were identified, amongst 95 and 55 proteins were found to be downregulated and upregulated, respectively. This is the first study that reported the global proteome changes in C. elegans against toxin. Our findings suggested involvement of several regulatory proteins that appear to play a role in various molecular functions in combating toxin-mediated microbial pathogenicity and/or host C. elegans immunity modulation. A proteomics approach using C. elegans can facilitate the understanding of how toxin can lead to intoxication, which pave a way for delineating how higher eukaryotes could evolve defenses to protect against bacterial toxin. Toxin infection nematode showed increased accumulation of proteins that respond to oxidative -stress, lipid metabolism, embryonic development, immune and inflammatory processes.

pathology↗