Biology subjects

Evidente, A.

Publications and source records attributed to Evidente, A..

5 recordsLinked to original sources

bioRxiv2025

Modulation of translational elongation by montanine alkaloids preferentially inhibits RNA viruses

Montanine, an Amaryllidaceae alkaloid, has demonstrated superior antiviral activity against dengue virus (DENV), SARS-CoV-2, vesicular stomatitis Indiana virus (VSV-G), and vesicular stomatitis virus pseudotyped with Ebola virus glycoprotein (VSV-ZGP), outperforming other antiviral alkaloids tested, including lycorine, narciclasine, tetracetylnarciclasine, and pancracine. We further showed that montanine inhibits translation in mammalian cells, as evidenced by a puromycin incorporation assay. Cryo-EM analysis revealed that montanine binds to the peptidyl transferase center of the human ribosome. A chemical genomics survey indicated that the knockdown of the GCN1 complex, which senses ribosome collisions and triggers the translation quality control process, increased the cytotoxicity of montanine while reducing viral infectivity. Together, these results suggest that the antiviral activity of montanine is closely linked to its impact on translational elongation and GCN1-related stress responses, underscoring the potential of translation control as a targeted mode for RNA virus therapeutics. Significance StatementMontanine, an alkaloid from the Amaryllidaceae family known for its diverse bioactivities, was identified as a potent antiviral compound from a library of natural plant- and fungus-derived substances. Through a combination of biochemical assays and cryo-EM analysis, we discovered that montanine binds to the peptidyl transfer center of the human ribosome, effectively inhibiting protein synthesis. Based on these findings and a chemical genomics approach, we hypothesize that the translational control of montanine triggers a cellular response that impedes viral replication. We propose that molecules capable of modulating translation efficacy could serve as unique lead compounds in the development of broad-spectrum antiviral agents.

biochemistry↗

bioRxiv2025

Ophiobolin A selectively alters mitochondria, metabolism and redox biology in breast cancer and mammary epithelial cells which have undergone epithelial to mesenchymal transition

Breast cancer progression is facilitated by the epithelial to mesenchymal transition (EMT), generating cancer cells with enhanced metastatic capacity and resistance to chemotherapeutics. EMT is known to impart changes in metabolic pathways and mitochondrial function. Here, we show a natural product possesses EMT-specific cytotoxic activity via alterations in metabolic and mitochondrial functions. The fungus-derived sesterterpenoid, ophiobolin A (OpA), possesses nanomolar cytotoxic activity and a high therapeutic index, although its target and mechanism of action remain unknown. Here, we utilized a model of mammary epithelial cells and breast cancer cell lines with and without EMT features to characterize the mechanism of selectivity towards EMT(+) cells by OpA and to identify novel targets for the treatment of EMT-enriched breast cancer. Proteins interacting with OpA in EMT(+) cells were identified through proteomic studies. We utilized trans-mitochondrial cybrids to determine that mitochondria mediate sensitivity to OpA. Furthermore, we report effects on glycolysis, oxidative metabolism, and disruption of metabolite abundance in the TCA cycle. Alterations to mitochondrial iron concentrations and glutathione production, mediated partly by OpA engagement with the metabolic proteins CISD3 and SLC25A40, were also detected in EMT(+) cells. Antioxidant mechanisms are activated by OpA in EMT(+) cells via the NRF2-ARE pathway, verified by decreased cytotoxicity in EMT(+) cells pretreated with the NRF2 activator CDDO. Collectively, we conclude that OpA selectivity toward EMT is mediated by the mitochondria, and at sub-cytotoxic levels, generates a metabolic shift leading to cell death countered by antioxidant mechanisms.

cancer biology↗

bioRxiv2025

PANoptosis, a combination of inflammatory cell death mechanisms, induced 1 by Ophiobolin A in breast cancer cell lines

An unmet challenge in managing breast cancer is treatment failure due to resistance to apoptosis-inducing chemotherapies. Thus, it is important to identify novel non-apoptotic therapeutic agents. Several non-apoptotic programmed cell death pathways utilize specific cellular signaling events to trigger lytic and pro-inflammatory cell death. PANoptosis, which encompasses pyroptosis, apoptosis and necroptosis, is of paramount importance in the regulation of cell death and immune responses. Our study illustrates that ophiobolin A (OpA) is an anti-cancer agent that triggers lytic cell death in breast cancer cells, including triple-negative breast cancer (TNBC), via a mechanism dependent on RIPK1. This study reveals that OpA induces typical pyroptosis-like characteristics, including cellular swelling, plasma membrane rupture, GSDMD cleavage and release of cytokines in breast cancer cells. The involvement of caspase 3, RIPK1, and GSDMD suggests that PANoptosis is activated upon OpA treatment in breast cancer. The induction of pro-inflammatory cell death suggests potential applications for OpA in cancer treatment.

cancer biology↗

bioRxiv2020

Epithelial-mesenchymal transition sensitizes breast cancer cells to cell death via the fungus-derived sesterterpenoid ophiobolin A

The epithelial-mesenchymal transition (EMT) imparts properties of cancer stem-like cells, including resistance to frequently used chemotherapy, necessitating the identification of molecules that induce cell death specifically in stem-like cells with EMT properties. Herein, we demonstrate that breast cancer cells enriched for EMT features are more sensitive to cytotoxicity induced by ophiobolin A (OpA), a sesterterpenoid natural product. Using a model of experimentally induced EMT in human mammary epithelial (HMLE) cells, we show that EMT is both necessary and sufficient for OpA sensitivity. Moreover, prolonged, sub-cytotoxic exposure to OpA is sufficient to reduce migration, sphere formation, and resistance to doxorubicin. OpA is well-tolerated in mice and treatment with OpA alone reduces tumor burden. These data identify a driver of EMT-driven cytotoxicity with significant potential for use either in combination with standard chemotherapy or for tumors enriched for EMT features.

cancer biology↗

bioRxiv2019

The fungal sesquiterpenoid pyrenophoric acid B uses the plant ABA biosynthetic pathway to inhibit seed germination.

HighlightThe fungus Pyrenophora semeniperda produces pyrenophoric acid B, a small molecule that exploits the plant ABA biosynthetic pathway to reduce seed germination, increasing its reproductive success.\n\nAbstractPyrenophoric acid (P-Acid), P-Acid B and P-Acid C are three phytotoxic sesquiterpenoids produced by the ascomycete seed pathogen Pyrenophora semeniperda, a fungus proposed as a mycoherbicide for biocontrol of cheatgrass, an extremely invasive weed. When tested in cheatgrass bioassays these metabolites were able to delay seed germination, with P-Acid B being the most active compound. Here, we have investigated the cross-kingdom activity of P-Acid B and its mode of action and found that it activates the ABA signaling pathway in order to inhibit seedling establishment. P-Acid B inhibits seedling establishment in wild-type Arabidopsis thaliana while several mutants affected in the early perception as well as in downstream ABA signaling components were insensitive to the fungal compound. However, in spite of structural similarities between ABA and P-Acid B, the latter is not able to activate the PYR/PYL family of ABA receptors. Instead, we have found that P-Acid B uses the ABA biosynthesis pathway at the level of alcohol dehydrogenase ABA2 to reduce seedling establishment. We propose that the fungus Pyrenophora semeniperda manipulates plant ABA biosynthesis as a strategy to reduce seed germination, increasing its ability to cause seed mortality and thereby increase its fitness through higher reproductive success.

plant biology↗