Biology subjects

Manna, S. K.

Publications and source records attributed to Manna, S. K..

7 recordsLinked to original sources

bioRxiv2026

Profilin1 regulates triple negative breast cancer cells migration through stabilization of Angiomotin and thereby YAP nuclear translocation

The Hippo pathway effector YAP1 is a potent oncogenic driver in triple-negative breast cancer (TNBC) and its activity is restrained by the scaffold protein Angiomotin-p130 (AMOT). AMOT is itself short-lived, being targeted for proteasomal degradation by NEDD4-family E3 ubiquitin ligases that dock at its L/P-PxY motifs. Here we identify Profilin1 (PFN1), an actin-binding protein with established actin-independent tumour-suppressive signalling functions in TNBC as a direct binding partner and stabilizer of AMOT. PFN1 and AMOT are co-immunoprecipitated, they share 70 common interactors and NEDD4 is one of them. Protein-protein docking shows the interaction of PFN1 on the first PPxY motif of AMOT, through its actin-binding domain. We further show that PFN1s binding leaves the AMOT LPTY motif and both coiled-coil domains entirely unoccupied. Site-directed mutagenesis of AMOT PPxY motifs shows that PFN1 binding is unaffected by substitution of the PPxY tyrosines Y242 and Y287, either alone or in combination, indicating that PFN1 engages through its actin-binding domain. Functionally, PFN1 stabilizes AMOT as shown by cycloheximide-chase assay in TNBC. PFN1 induction increases cytoplasmic retention of YAP1, reduces TEAD occupancy at the CTGF promoter and thereby suppresses TNBC cell migration. Thus, this study suggests that PFN1 deregulates tumour cells migration by interacting with AMOT through its actin-binding domain, stabilizing AMOT and thereby arresting YAP in the cytoplasm, which might be an important therapeutic target to regulate TNBC.

cancer biology↗

bioRxiv2025

Defects in lamin A-Prohibitin crosstalk leads to ROS elevation and OxPhos imbalance in laminocardiomyopathy

Lamins are critical for maintaining nuclear homeostasis, chromosome positioning, and cellular mechanotransduction, which involves the transfer of mechanical signals from the cellular microenvironment to the nucleus. Recent studies have also highlighted the involvement of lamin A in mitochondrial homeostasis and the regulation of reactive oxygen species production. Missense mutations in lamin A are linked to a spectrum of diseases known as laminopathies, which include conditions such as dilated cardiomyopathy (DCM), muscular dystrophy, and progeria. One such mutation, K97E, is associated with DCM, causing severe cardiac complications that can lead to myocardial infarction in extreme cases. Our study reveals a detailed pathogenic cascade in K97E-transfected cells involving disrupted interaction with Prohibitin-2, a key mitochondrial protein. Mitochondria exhibit increased fission, reduced fusion, and fragmentation, due to OPA1 downregulation and DRP1 recruitment driven by actin cytoskeletal remodelling. Impaired Rho-ERK- FAK signalling reduces F-actin assembly, elevating G-actin, which further promotes mitochondrial fission. This feedback loop leads to mitochondrial depolarisation, ATP deficiency, and global metabolic catastrophe, in particular cholesterol metabolism, accompanied by elevated ROS. In cardiomyocytes, such dysfunction may underlie contractile deficits and arrhythmias. Our findings establish PHB2 as a critical node linking nuclear integrity, cytoskeletal architecture, and mitochondrial homeostasis, offering new insights into DCM pathogenesis and therapeutic targets. Our findings elucidate the pivotal role of lamin A in cellular energetics and mechanotransduction, offering novel insights into DCM pathophysiology, which in turn opens avenues for developing targeted therapeutic strategies. TeaserLamin A K97E mutation alters cellular metabolome through disturbed mitochondrial and actin homeostasis in a feedback loop with PHB2 at its hub and causes gross pathogenesis of DCM. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=120 SRC="FIGDIR/small/665267v1_ufig1.gif" ALT="Figure 1"> View larger version (50K): org.highwire.dtl.DTLVardef@176d89aorg.highwire.dtl.DTLVardef@1868703org.highwire.dtl.DTLVardef@109dff8org.highwire.dtl.DTLVardef@14f469a_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOFigure 5C_FLOATNO Gross mitochondrial defects arising from PHB2 and actin perturbations leading to severe metabolic and bioenergetic effects during K97E mutation of lamin A C_FIG

cell biology↗

bioRxiv2024

Distance between miRNA responsive elements selectively enhances target specificity with reduced cellular toxicity by miRNA-mediated synergism

Despite the emergence of miRNAs as promising therapeutic tools in cancer management, most clinical trials have not been successful due to their cytotoxic effects. Here, we have investigated the factors regulating the effect of miRNA-mimic pairs in enhancing target gene specificity while reducing cellular toxicity. Synergistic reductions by the miRNA-mimic pairs were observed for the 3-UTRs of common target genes with miRNA-responsive elements (MREs) preferentially located at a distance of 200-800bp. Deletion of either of the miRNA seed sequences resulted in a loss of synergism. Furthermore, we performed small RNA-sequencing to identify significantly downregulated miRNAs in Oral cancer. Consequently, we transfected let-7c-5p and miR-125b-5p miRNA mimics either alone or in combination at half-dose concentrations and determined the expression levels of their common and unique target genes in oral cancer cells. Significant reductions in target gene expression were observed for genes containing MREs for both miRNA mimics within the preferential distance. Proteomic data revealed that the let-7c-5p and miR-125b-5p miRNA-mimic pairs synergistically reduced the expression of their common target genes, hexokinase 2 (HK2) and branched-chain amino acid transaminase 1 (BCAT1), in cancer cells. However, unique target genes did not exhibit any significant alterations in their protein levels. The effect of HK2 and BCAT1 downregulation was also reflected in the metabolomic profiling of cancer cells, specifically affecting glycolysis and the BCAA degradation pathways. As a result of the metabolic impairment caused by the synergistic effect of miRNA mimic pairs, oral cancer cells showed a significant reduction in proliferation, migration, and spheroid formation compared to cells treated with either single miRNA. The synergistic effect of these miRNA mimics was lost in normal keratinocytes, possibly due to low expression levels of the target oncogenes, suggesting a cancer cell-specific effect of this mechanism.

cancer biology↗

bioRxiv2023

Identification of glucose-independent metabolic pathways associated with anti-proliferative effect of metformin, their coordinate derangement with cMyc downregulation and reversibility in liver cancer cells.

Several studies indicated anti-cancer effects of metformin in liver cancer. This was attributed to the activation of LKB-AMPK axis, which is associated with anti-hyperglycaemic effect and cytotoxicity. However, despite lack of evidence on cytotoxic effect of physiological metformin concentrations and ability of cancer cells to survive under glucose-deprivation, no study has examined the glucose-independent effect of non-cytotoxic metformin or metabolic reprogramming associated with it. In addition, no study has ever been conducted on reversibility of anti-cancer effects of metformin. Here, the dose-dependent effects of metformin on HepG2 cells were examined in presence and absence of glucose. The longitudinal evolution of metabolome was analyzed along with gene and protein expression as well as their correlations with and reversibility of cellular phenotype and metabolic signatures. Metformin concentrations up to 2.5mM were found to be non-cytotoxic but anti-proliferative irrespective of presence of glucose. Apart from mitochondrial impairment, derangement of fatty acid desaturation, one-carbon, glutathione and polyamine metabolism were associated with non-cytotoxic metformin treatment irrespective of glucose supplementation. Depletion of pantothenic acid, downregulation of essential amino acid uptake, metabolism and purine salvage were identified as novel glucose-independent effects of metformin. These were significantly correlated with cMyc expression and reduction in proliferation. Rescue experiments established reversibility upon metformin withdrawal and tight association between proliferation, metabotype and cMyc expression. Taken together, derangement of novel glucose-independent metabolic pathways and concomitant cMyc downregulation co-ordinately contribute to anti-proliferative effect of metformin even at non-cytotoxic concentrations, which is reversible and may influence its therapeutic utility.

cancer biology↗

bioRxiv2020

Characterizations of SARS-CoV-2 mutational profile, spike protein stability and viral transmission

The recent pandemic of SARS-CoV-2 infection has affected more than 3.0 million people worldwide with more than 200 thousand reported deaths. The SARS-CoV-2 genome has a capability of gaining rapid mutations as the virus spreads. Whole genome sequencing data offers a wide range of opportunities to study the mutation dynamics. The advantage of increasing amount of whole genome sequence data of SARS-CoV-2 intrigued us to explore the mutation profile across the genome, to check the genome diversity and to investigate the implications of those mutations in protein stability and viral transmission. Four proteins, surface glycoprotein, nucleocapsid, ORF1ab and ORF8 showed frequent mutations, while envelop, membrane, ORF6 and ORF7a proteins showed conservation in terms of amino acid substitutions. Some of the mutations across different proteins showed co-occurrence, suggesting their functional cooperation in stability, transmission and adaptability. Combined analysis with the frequently mutated residues identified 20 viral variants, among which 12 specific combinations comprised more than 97% of the isolates considered for the analysis. Analysis of protein structure stability of surface glycoprotein mutants indicated viability of specific variants and are more prone to be temporally and spatially distributed across the globe. Similar empirical analysis of other proteins indicated existence of important functional implications of several variants. Analysis of co-occurred mutants indicated their structural and/or functional interaction among different SARS-COV-2 proteins. Identification of frequently mutated variants among COVID-19 patients might be useful for better clinical management, contact tracing and containment of the disease.

genomics↗

bioRxiv2020

Loss of mitochondrial localization of human FANCG causes defective FANCJ helicase

Fanconi anemia (FA) is a unique DNA damage repair pathway. Almost twenty-two genes have been identified which are associated with the FA pathway. Defect in any of those genes causes genomic instability, and the patients bear the mutation become susceptible to cancer. In our earlier work, we have identified that Fanconi anemia protein G (FANCG) protects the mitochondria from oxidative stress. In this report, we have identified eight patients having mutation (C.65G>C; p.Arg22Pro) in the N-terminal of FANCG. The mutant protein hFANCGR22P is able to repair the DNA and able to retain the monoubiquitination of FANCD2 in FANCGR22P/FGR22P cell. However, it lost mitochondrial localization and failed to protect mitochondria from oxidative stress. Mitochondrial instability in the FANCGR22P cell causes the transcriptional down-regulation of mitochondrial iron-sulphur cluster biogenesis protein Frataxin (FXN) and resulting iron deficiency of FA protein FANCJ, an iron-sulphur containing helicase involved in DNA repair.

cancer biology↗

bioRxiv2018

Aperture Phase Modulation with Adaptive Optics: A Novel Approach for Speckle Reduction and Structure Extraction in Optical Coherence Tomography

AbstractSpeckle is an inevitable consequence of the use of coherent light in optical coherence tomography (OCT), and often acts as noise that obscures micro-structures of biological tissue. We here present a novel method of suppressing speckle noise intrinsically compatible with adaptive optics (AO) in OCT system: by modulating the phase inside the imaging system pupil aperture with a segmented deformable mirror, thus producing minor perturbations in the point spread function (PSF) to create un-correlated speckle pattern between B-scans, and further averaging to wash out the speckle but maintain the structures. It is a well-controlled and universal method which can efficiently determine the optimal range of phase modulation that minimizing speckle noise while maximizing image resolution and signal strength for different systems and/or samples. As an active method, its effectiveness and efficiency were demonstrated by both ex-vivo non-biological and in-vivo biological applications.

bioengineering↗