Biology subjects

Lal, B.

Publications and source records attributed to Lal, B..

5 recordsLinked to original sources

bioRxiv2026

Toward pharmacologic therapy for glioblastoma: Characterization of the very long-chain acyl-CoA synthetase 3 (ACSVL3) inhibitor Grassofermata

Malignant brain tumors are among the most aggressive and difficult to treat human cancers. Glioblastomas (World Health Organization grade IV gliomas) are particularly lethal and refractory to treatment. Few drugs exist that are even somewhat effective. Our investigation of the physiologic role of fatty acid (FA) activating enzymes (acyl-CoA synthetase; ACS) identified an ACS that was widely expressed in gliomas but not in normal glial cells. Depletion of this enzyme, ACSVL3 (very long-chain ACS3), by knockdown or knockout decreased the malignant behavior of several glioma cell models including U87MG and Mayo-22 cells both in culture and when grown as xenografts. Hypothesizing that ACSVL3 is a potential therapeutic target in glioma, we conducted a search for inhibitors of this enzyme and found that CB5 (grassofermata) was a promising candidate. Treating U87MG glioma cells with CB5 slowed growth in monolayer culture; the growth rate was similar to that seen in cells in which ACSVL3 was either knocked down or knocked out. CB5 inhibited growth in a dose-dependent manner over a narrow range, and concentrations above 10 {micro}M were toxic. Treatment at the lower dose of 3 {micro}M inhibited growth of U87MG cells but was reversible, suggesting that this dose was not toxic. CB5-treated U87MG cells exhibited an altered morphology with a larger size and longer projections. In contrast, normal human fibroblasts treated with 10 {micro}M CB5, a concentration that was toxic to U87MG cells, showed no effect on either growth rate or morphology. Treating U87MG cells with 3 {micro}M CB5 induced differentiation as shown by increased expression of the astrocyte-specific marker glial fibrillary acidic protein (GFAP). In contrast, GFAP levels remained low in ACSVL3 knockdown cells. CB5-treated U87MG cells were less invasive, and thus less malignant, than either untreated cells or ACSVL3 knockout cells when assessed by a scratch wound healing assay. Acute treatment of U87MG cells with 3 {micro}M CB5 decreased the ability of these cells to degrade FA of differing chain lengths from 16-24 carbons by {beta}-oxidation, suggesting that decreased ACS enzyme activity contributes at least in part to the drugs mechanism of action. NOD/SCID mice receiving up to 32 mg/kg/day CB5 by intraperitoneal injection showed no obvious side effects, suggesting that the drug was well-tolerated. Xenografts induced by subcutaneous injection of U87MG cells in the flanks of NOD/SCID mice were allowed to grow for 8 days after which half of the mice were treated with 2 mg/kg/day CB5. After 7 days of treatment, xenograft growth slowed in the treated mice and by 12 days tumor size had begun to decrease, suggesting therapeutic efficacy. When a similar study was done using xenografts induced by subcutaneous injection of Mayo-22 cells, which are maintained as subcutaneous tumors in mice rather than in cell culture, the effect of CB5 on tumor growth or weight at sacrifice was not statistically significant. The results of these studies suggest that CB5 may have therapeutic value in malignant glioma. Additional studies using other glioma models and other drugs chemically related to CB5 seem warranted.

cancer biology↗

bioRxiv2026

Deep-learning-enabled morphodynamic analysis of drug responses in a biomimetic fibrin-based 3D glioblastoma invasion model

Glioblastoma (GBM) lethality arises from aggressive invasion and diffuse infiltration of brain tissue. Conventional GBM preclinical models often fail to predict clinical therapeutic efficacy because they do not recapitulate the pathological extracellular matrix (ECM) cues that drive tumor invasion. Here, we present an ECM mimetic 3D platform using a fibrin scaffold to recapitulate the hemorrhagic, pro-thrombotic tumor microenvironment characteristic of high-grade gliomas. This fibrin scaffold induces a pro-invasive phenotype in GBM spheroids by upregulating proliferation/cell cycle- (MYC, FOXOM1, CCND1) and invasion-associated-(CTSS, FOXM1, CCND1) genes. Traditional cell morphology quantification methods (e.g., circularity) distil complex shapes into singular metrics and cannot capture the nuances of invasion. To address this limitation, we have applied a deep-learning segmentation pipeline (MARS-Net) and high-content morphodynamic descriptors. By using the Preserving Heterogeneity (PHet) algorithm, the 3D platform accurately classifies invasiveness levels and captures the invasion-inhibitory effects of potential repurposable drug candidates. We demonstrate that our model can predict a spheroids long-term invasive fate with high accuracy using only partial image sets from early time-points, rather than the complete time-course images. Our work presents an in vivo-like, scalable 3D platform integrated with a quantitative high-throughput pipeline to elucidate GBM invasion mechanisms and to evaluate anti-invasive compounds.

bioengineering↗

bioRxiv2023

SARS-CoV-2 antibodies cross-react and enhance dengue infection

The presence of non-neutralizing antibodies of any dengue serotype, increase the severity of subsequent infection by other dengue serotypes. During SARS-CoV-2 pandemic, the number of symptomatic dengue cases increased in India. We describe that antibodies isolated from convalescent plasma from COVID-19 patients enhances DENV2 infection in vitro. CR3022, one antibody against SARS-CoV-2 spike protein, also showed elevated DENV2 infection in vitro. In silico protein-protein interactions between the spike antibodies and the DENV2 E-protein revealed significant interactions. Likewise, few monoclonal/polyclonal antibodies against SARS-CoV-2 showed increased dengue infection in vitro. Importantly, the AG129 mice infected with SARS-CoV-2 three-weeks prior to DENV2 infection, showed elevated dengue pathogenesis. Thus, highlighting the possibilities of elevated infection and symptomatic dengue disease in COVID-19 survivors.

immunology↗

bioRxiv2021

The Endosomal pH Regulator NHE9 is a Driver of Stemness in Glioblastoma

A small population of self-renewing stem cells initiate tumors and maintain therapeutic resistance in glioblastoma. Given the limited treatment options and dismal prognosis for this disease there is urgent need to identify drivers of stem cells that could be druggable targets. Previous work showed that the endosomal pH regulator NHE9 is upregulated in glioblastoma and correlates with worse survival prognosis. Here, we probed for aberrant signaling pathways in patient-derived glioblastoma cells and found that NHE9 increases cell surface expression and phosphorylation of multiple receptor tyrosine kinases by promoting their escape from lysosomal degradation. Downstream of NHE9-mediated receptor activation, oncogenic signaling pathways converged on the JAK2-STAT3 transduction axis to induce pluripotency genes Oct4 and Nanog and suppress markers of glial differentiation. We used both genetic and chemical approaches to query the role of endosomal pH in glioblastoma phenotypes. Loss-of-function mutations in NHE9 that failed to alkalinize endosomal lumen did not increase self-renewal capacity of gliomaspheres in vitro. However, monensin, a chemical mimetic of Na+/H+ exchanger activity, and the H+ pump inhibitor bafilomycin bypassed NHE9 to directly alkalinize the endosomal lumen resulting in stabilization of receptor tyrosine kinases and induction of Oct4 and Nanog. Using orthotopic models of primary glioblastoma cells we found that NHE9 increased tumor initiation in vivo. We propose that NHE9 initiates inside-out signaling from the endosomal lumen, distinct from the established effects of cytoplasmic and extracellular pH on tumorigenesis. Endosomal pH may be an attractive therapeutic target that diminishes stemness in glioblastoma, agnostic of specific receptor subtype. SignificanceA well-known hallmark of cancer is excessive acidification of tumor microenvironment, caused by upregulation of Na+/H+ exchanger activity on the cancer cell membrane. However, the role of organellar pH in tumor biology has not been established. This study identifies a mechanistic link between upregulation of the endosomal Na+/H+ exchanger NHE9 and stemness properties in glioblastoma, the most malignant and common brain tumor in adults. By increasing pH of the recycling endosome, NHE9 exerts a broad effect on post-translational stability and activation of multiple receptor tyrosine kinases, leading to increased stem cell-like properties of self-renewal and tumor initiation in glioblastoma models. Our findings suggest that targeting NHE9 or endosomal pH could be an effective strategy for receptor agnostic glioblastoma treatment.

cancer biology↗

bioRxiv2021

Genome sequencing and molecular characterisation of XDR Acinetobacter baumannii reveal complexities in resistance: Novel combination of Sulbactam-Durlobactam holds promise for therapeutic intervention

Acinetobacter baumannii is an emerging nosocomial strain expressing extensive drug resistance (XDR). Whole-genome sequencing and molecular characterisation analysis revealed the presence of carbapenemase in 92.86% of studied Indian isolates having blaOXA-51, blaOXA-23, blaOXA-58, and blaNDM genes, with a few evidences of dual carbapenemase genes. As per the MLST scheme, IC2Oxf/CC2Pas was the predominant clone, with 57.14% isolates belonging to this lineage. The presence of {beta}-lactamases has rendered sulbactam (SUL) resistance (MIC: 16-256{micro}g/ml) in all the studied isolates. The efficacy of novel durlobactam (DUR) in inhibiting {beta}-lactamases and PBP2 was assessed through in-silico inter-molecular interaction analysis. Several non-synonymous single nucleotide polymorphisms (nsSNPs) were identified in PBP2 (G264S, I108V, S259T) and PBP3 (A515V, T526S) sequences. Minimal variations were recorded in the protein-backbone dynamics in active-site motifs of wild-type (WT) and mutants (MT), which correlated with the negligible binding energy fluctuations for PBP3-SUL (-5.85{+/-}0.04Kcal/mol) and PBP2-DUR (-5.16{+/-}0.66Kcal/mol) complexes. Furthermore, stronger binding affinities and low inhibition constants were noted in DUR complexed with OXA23 (-7.36Kcal/mol; 4.01{micro}M), OXA58 (-6.44Kcal/mol; 19.07{micro}M) and NDM (-6.82Kcal/mol; 10.01{micro}M) when compared with conventional drugs avibactam and aztreonam. Stable interaction profiles of DUR, can possibly restore SUL activity against both PBP3WT and PBP3MTs. The study establishes the efficacy of novel SUL-DUR combination as a successful treatment strategy to combat emerging XDR strains.

microbiology↗