Biology subjects

Bhandari, N.

Publications and source records attributed to Bhandari, N..

6 recordsLinked to original sources

bioRxiv2025

Targeting Neutrophil Extracellular Traps to inhibit Colon Cancer Tumor Necrosis and Metastasis

Necrosis, conventionally thought of as a passive consequence of aggressive tumor growth, is associated with poor prognosis in colorectal cancer (CRC). We recently discovered that necrosis can be caused by neutrophils and neutrophil extracellular traps (NETs) aggregates driving vascular occlusion within the tumor vasculature in models of breast cancer. Here, we evaluated the role of NETs in inducing necrosis and metastasis in CRC. We found that the numbers of neutrophils primed to form NETs were elevated in the circulation of patients with CRC as compared to controls. CD177Low neutrophils were also elevated, and they showed reduced extravasation capacity with intact ability to form NETs. The extent of necrosis correlated with metastasis (stage IV disease), independent of tumor size, in our human cohort. In both human and murine CRC tumors, necrotic regions were characterized by neutrophil infiltration and NET accumulation, and NET aggregates were observed in the vasculature next to the necrotic regions. Single cell RNA sequencing and spatial transcriptomic analysis of human CRC and liver metastases revealed that necrotic tumors activate pathways associated with increased metastatic potential, including epithelial-to-mesenchymal-transition. Using a mouse model of DNA mismatch repair proficient CRC, we found neutrophil infiltration and NETs increased with tumor progression. Genetic or pharmacological inhibition of NET formation decreased necrosis and metastasis, and importantly enhanced chemotherapy efficacy. Altogether, our findings show that NET formation in human CRC is a key feature of tumor necrosis, that it is associated with metastasis, and further suggest that preventing NET formation may offer clinical benefits to CRC patients.

cancer biology↗

bioRxiv2025

TGFb Regulated Small GTPase RHOV interact with PEAK1 and drive MYC Expression to Promote Cellular Proliferation, Migration and Etoposide resistance

1.Non-small cell lung cancer (NSCLC) remains a leading cause of cancer-related mortality, driven by tumor heterogeneity, metastasis, and therapeutic resistance. While Rho GTPases are well-established regulators of oncogenic processes, the role of the atypical GTPases in NSCLC remains unexplored. Here, we identified RHOV as one of the commonly upregulated Rho GTPases in NSCLC. Analysis of four independent patient cohorts revealed that elevated RHOV expression serves as a robust and independent prognosticator of NSCLC patients specifically early-stage disease. Functionally, RHOV knockdown significantly inhibited cell proliferation, whereas its overexpression enhanced proliferation. Similarly, RHOV depletion suppressed cell migration by disrupting cytoskeletal dynamics, while its overexpression promoted migratory capacity. Mechanistically, we demonstrated that RHOV is a direct transcriptional target of the TGF{beta}-SMAD3 signaling pathway. RNA-seq analysis identified MYC as a critical downstream mediator of RHOV; RHOV knockdown reduced MYC expression, impairing mitochondrial oxidative phosphorylation and inducing ROS-mediated DNA damage--a phenotype rescued by MYC overexpression. Furthermore, RHOV inhibition sensitized NSCLC cells to etoposide but not doxorubicin. immunoprecipitation coupled with LC-MS revealed PEAK1 as a key interactor of RHOV. The RHOV-PEAK1 complex proved essential for NSCLC proliferation, as PEAK1 silencing abolished RHOV- driven MYC upregulation and tumor growth. This axis sustains MYC levels and activates PI3K/MAPK signaling. Intriguingly, PEAK1 depletion elevated TGF-{beta} levels, which suppressed RHOV expression, establishing a negative feedback loop wherein PEAK1 maintains RHOV by inhibiting TGF-{beta} signaling. Collectively, our findings establish RHOV as a prognostic biomarker and a driver of NSCLC progression via the RHOV-PEAK1-MYC axis, highlighting its potential as a therapeutic target. HighlightsO_LIRHOV upregulation predicts poor NSCLC survival, particularly in early-stage disease. C_LIO_LIThe RHOV-PEAK1 interaction is crucial for NSCLC growth and cell migration. C_LIO_LIRHOV inhibition sensitizes NSCLC cells to Etoposide treatment. C_LIO_LIRHOV expression is sustained via a PEAK1-TGF{beta} negative feedback loop. C_LI

cancer biology↗

bioRxiv2025

NF-κB signaling directs a program of transient amplifications at innate immune response genes

The cellular response to pathogens involves an intricate response directed by key innate immune signaling pathways which is characterized by cell-to-cell heterogeneity. How this heterogeneity is established and regulated remains unclear. We describe a program of transient site-specific gains (TSSG) producing extrachromosomal DNA (ecDNA) of immune-related genes in response to innate immune signaling. Activation of NF-{kappa}B drives TSSG of the interferon receptor gene cluster through inducible recruitment of the transcription factor RelA and the pre-replication complex member MCM2 to an epigenetically regulated TSSG control element. Targeted recruitment of RelA or p300 are sufficient to induce TSSG formation. RelA and MCM2 specify a program of TSSG for at least six and as many as 179 regions enriched in innate immune response genes. Identification of this program reveals regulated production of ecDNA as a mechanism of heterogeneity in the host response.

molecular biology↗

bioRxiv2025

MRPL47 Deficiency Drives Mitochondrial Dysfunction via ROS/p38-MAPK/CDKN1A Signaling in Non-Small Cell Lung Cancer

Mitoribosomes play a pivotal role in cellular energy metabolism by synthesizing proteins involved in oxidative phosphorylation (OXPHOS) system. Dysregulation of mitoribosomes has been linked to Cancer, yet there have been no studies demonstrating the genetics and epigenetic landscape of mitoribosomal proteins (MRPs). In this study, we conducted a comprehensive analysis of expression, copy number variations, mutations, data from TCGA NSCLC patients to elucidate the genetic mechanism regulating MRPs in NSCLC. Consequently, we identified MRPL47, a significantly amplified and overexpressed mitoribosomal gene. We also found significant correlation of MRPL47 expression and copy number with patients survival. Functionally, we showed that inhibition of MRPL47 was associated with reduced cell proliferation and migration. Furthermore, silencing MRPL47 impaired the enzymatic activity of electron chain complex I & III leading to a defective OXPHOS system and elevated mitochondrial ROS level. Further, we showed ROS-mediated increase in CDKN1A through the p38 MAPK pathway. The increased CDKN1A level induced G1 cell cycle arrest by inhibiting E2F activity. RNA sequencing analysis further confirmed that MRPL47 hinders cell growth by inhibiting E2F pathway. Additionally, we found that MRPL47 selectively regulates mitochondrial translation of specific OXPHOS proteins rather than influencing all mitochondrial proteins. Altogether, these findings suggest that MARPL47, is amplified and overexpressed in NSCLC and plays a critical role in tumor progression by regulating ROS signaling pathways.

cancer biology↗

bioRxiv2024

GJB3, a gap junction gene, supports cell growth by mediating cystine uptake and regulating cellular stress pathways in SLC7A11 low adenocarcinomas

Gap junctions are specialized intercellular connections that directly connect the cytoplasm of two cells via protein structure called connexins. Despite extensive research on many cell surface proteins, Gap junction proteins are understudied in cancer. In this study, we used TCGA data to identify genetic and epigenetic changes associated with Gap junction proteins. The analysis identified GJB3 as a key gene with differential methylation and expression patterns, with notable overexpression in COAD and LUAD, correlating significantly with patient survival outcomes. GJB3 knockdown studies revealed reduced cell proliferation and migration. Transcriptomic analysis revealed that GJB3 knockdown induced a cellular stress response, characterized by activation of starvation and autophagy pathways. Western blot analysis confirmed these findings, showing increased phosphorylation of eIF2 and activation of the GCN2-eIF2-ATF4 signaling axis subsequent autophagy induction. We also found that sustained autophagy induced apoptosis mediated cell death. Metabolic profiling revealed a significant decrease in cystine levels in GJB3-deficient cells. We demonstrated that GJB3 plays a crucial role in cystine uptake, especially in cells with low SLC7A11 expression. Furthermore, we showed that GJB3 can be targeted using specific antibodies, establishing it as a potential therapeutic strategy for GJB3-dependent cancers. These findings highlight the significance of GJB3 in cancer progression and its potential as a therapeutic target, offering new insights into its epigenetic regulation and functional role in cellular stress and survival mechanisms.

cancer biology↗

bioRxiv2023

Disulfiram reduces atherosclerosis and enhances efferocytosis, autophagy, and atheroprotective gut microbiota in hyperlipidemic mice.

Pyroptosis executor Gasdermin (GsdmD) promotes atherosclerosis in mice and humans. Disulfiram (DSF) was recently shown to potently inhibit GsdmD, but the in-vivo efficacy and mechanism of DSFs anti-atherosclerotic activity is yet to be explored. We used human/mouse macrophages and a hyperlipidemic mouse model of atherosclerosis to determine DSF anti-atherosclerotic efficacy and mechanism. DSF-fed hyperlipidemic apoE-/- mice showed significantly reduced IL-1{beta} release upon in-vivo Nlrp3 inflammasome assembly and showed smaller atherosclerotic lesions ([~]27% and 29% reduction in males and females, respectively). The necrotic core area was also smaller ([~]50% and 46% reduction in DSF-fed males and females, respectively). DSF induced autophagy in macrophages, hepatocytes/liver, and in atherosclerotic plaques. DSF modulated other atheroprotective pathways such as efferocytosis, phagocytosis, and gut microbiota. DSF-treated macrophages showed enhanced phagocytosis/efferocytosis, with a mechanism being a marked increase in cell-surface expression of efferocytic receptor MerTK. Atomic-force microscopy analysis revealed altered biophysical membrane properties of DSF treated macrophages, showing increased ordered-state of the plasma membrane and increased adhesion strength. Furthermore, the 16sRNA sequencing of DSF-fed hyperlipidemic mice showed highly significant enrichment in atheroprotective gut microbiota Akkermansia and a reduction in atherogenic Romboutsia species. Taken together, our data shows that DSF can simultaneously modulate multiple atheroprotective pathways, and thus may serve as novel adjuvant therapeutic to treat atherosclerosis.

cell biology↗