Biology subjects

Pavlovic, T.

Publications and source records attributed to Pavlovic, T..

7 recordsLinked to original sources

bioRxiv2026

PFOS Disrupts Membrane Signaling and Epithelial Integrityin Fallopian Tube Cells

Perfluorooctane sulfonic acid (PFOS), a per- and polyfluoroalkyl substance (PFAS), is a widespread persistent environmental pollutant that has been implicated in various human health conditions, including infertility and cancer. Here, we investigate the effects of acute exposure to PFOS on human fallopian tube epithelial (FNE) cells that are essential for fertility and increasingly recognized as the origin site for high-grade serous ovarian cancer. We show that acute PFOS exposure changes morphology, arrests proliferation, impairs adhesion, and compromises epithelial integrity of FNE cells. Using transcriptomic profiling of FNE cells exposed to PFOS, we found increased expression of genes associated with stress-response signal transduction, including KRAS, and decreased expression of genes related to cholesterol transport and lipid homeostasis. We show that inhibition of MEK/ERK or cholesterol supplementation rescued changes in cell morphology. Further, we performed membrane fluidity measurements of cells exposed to PFOS and found elevated membrane disorder and fluidity. Our results are consistent with a model in which PFOS perturbs plasma membrane, activates stress-response signaling pathways, and impairs epithelial cell function. These studies establish a framework for understanding the effects of PFAS on cell physiology.

cell biology↗

bioRxiv2025

Protein characterization of the soybean malic enzyme family to select metabolic targets for seed oil improvement

Seeds are of great economic interest due to their organic composition. The metabolic pathways leading to the deposition of seed storage compounds, such as oil and proteins, are complex in terms of the number of enzymes involved, the regulatory context, and the variability among species. Previous studies indicated that mitochondrial NAD-dependent and plastidial NADP-dependent malic enzymes (MEs; EC 1.1.1.39 and 1.1.1.40, respectively) participate in providing reducing power and citrate or acetyl-CoA, respectively, to fatty acid biosynthesis in soybean (Glycine max L. Merr.) embryos. In this work, we analyzed the biochemical properties of enzymes belonging to the soybean ME family; which were obtained by recombinant expression and subsequent affinity purification. Our results show that NADP-ME1.1 has high affinity for the substrates malate and NADP and is specifically activated by glutamine, the main nitrogenous compound imported from maternal tissues to support the filling process. In addition, NAD-MEs exhibit differential kinetic parameters and regulation by key metabolites, making the isoforms better suited to fulfill non-redundant functions under certain physiological conditions. Activation by intermediates of glycolysis, the citric acid cycle, and lipogenesis indicated coordination between these pathways and malate metabolism. In turn, NAD-ME activity in soybean mitochondria would be regulated by the alternative association between linage 1 and 2 subunits. These findings provide new insights into intermediary metabolism in oilseeds and nominate specific soybean ME isoforms as biotechnological tools to be used in breeding programs.

biochemistry↗

bioRxiv2025

Suppression of Ovarian Cancer Cell Proliferation is Associated with Upregulation of Cell-Matrix Adhesion Programs and Integrin-β4-Induced Cell Protection from Cisplatin.

The role of extracellular matrix adhesion components in modulation of the treatment sensitivity of ovarian cancer (OC) cells is not well understood. Analysis of ovarian cancer TCGA gene expression data sets revealed an inverse correlation between genes involved in cell-cycle progression and extracellular matrix interactions including laminin-binding receptor integrin {beta}4, a major component of extracellular matrix adhesion. Gene ontology analysis also showed that in patient populations with low integrin {beta}4 expression, cell cycle-related programs were activated, while in populations with high expression of integrin {beta}4, the activation of these cell cycle programs was lower. Suppression of proliferation with CDK4/6 inhibitor Palbociclib stimulated integrin {beta}4 expression and induced protection against cisplatin in cells naturally expressing low levels of integrin {beta}4. Additionally, ovarian cancer patient-derived organoids showed reduced cisplatin sensitivity when pretreated with Palbociclib. Our data also showed that integrin {beta}4 overexpression decreased ovarian cancer cell proliferation and at the same time, attenuated cisplatin response. Our investigations reveal that expression of integrin {beta}4 inversely correlates with cell cycle progression programs, whether observed in expression data of OC patient samples or in various OC cell lines. Consistently with these results, the overexpression of ITGB4 gene in ovarian cancer cell lines correlated with reduced cell proliferation rates and diminished sensitivity to cisplatin, supporting the idea that integrin {beta}4 and likely its matrix ligands play critical roles in the regulation of cellular growth and chemoresistance of ovarian cancer cells.

cancer biology↗

bioRxiv2023

The Dietary Supplement Taurine Suppresses Ovarian Cancer Growth

Taurine, a non-proteogenic amino acid, and commonly used nutritional supplement can protect various tissues from degeneration associated with the action of the DNA-damaging chemotherapeutic agent cisplatin. Whether and how taurine protects human ovarian cancer (OC) cells from DNA damage caused by cisplatin is not well understood. We have found that OC ascites-derived cells contained significantly more intracellular taurine than cell cultures modeling OC. In culture, elevation of intracellular taurine concentration to OC ascites-cells-associated levels suppressed proliferation of various OC cell lines and patient-derived organoids, reduced glycolysis, and induced cell protection from cisplatin. Taurine cell protection was associated with decreased DNA damage in response to cisplatin. A combination of RNA sequencing, reverse phase protein arrays, live-cell microscopy, flow cytometry, and biochemical validation experiments provided evidence for taurine-mediated induction of mutant- or wild-type p53 binding to DNA, and activation of p53 effectors involved in negative regulation of the cell cycle (p21), and glycolysis (TIGAR). Paradoxically, taurines suppression of cell proliferation was associated with activation of pro-mitogenic signal transduction including ERK, mTOR, and increased mRNA expression of major DNA damage sensing molecules such as DNAPK, ATM and ATR. While inhibition of ERK or p53 did not interfere with taurines ability to protect cells from cisplatin, suppression of mTOR with Torin2, a clinically relevant inhibitor that also targets DNAPK and ATM/ATR, broke taurines cell protection. Our studies implicate that elevation of intracellular taurine could suppress cell growth, metabolism, and activate cell protective mechanisms involving mTOR and DNA damage sensing signal transduction.

cancer biology↗

bioRxiv2022

Compressive forces stabilise microtubules in living cells

Cell mechano-sensation and adaptation are supported by the actin network. The microtubule network is not considered to be directly sensitive to mechanical forces acting on a cell. However, recent studies on isolated microtubules in vitro have shown that bending forces have an impact on their structure, composition and lifespan, suggesting that, in a cellular context, microtubules may react to mechanical forces. We tested this hypothesis in living cells by subjecting them to cycles of compressive forces and found that microtubules became distorted, less dynamic and more stable. This mechano-stabilisation depends on CLASP2, which relocates from the end to the deformed shaft of microtubules. These results demonstrate that microtubules in living cells have mechano-responsive properties that allow them to resist and even counteract the forces to which they are subjected.

cell biology↗

bioRxiv2022

Extracellular Matrix Levels Modulate Outgrowths Dynamics in Ovarian Cancer.

Ovarian carcinoma (OC) forms outgrowths that extend from the outer surface of an afflicted organ into the peritoneum. OC outgrowth formation is poorly understood because there is limited availability of OC cell culture models to examine the behavior of cell assemblies that form outgrowths. Prompted by immunochemical evaluation of extracellular matrix (ECM) components, laminin {gamma}1 and collagens, in human tissues representing untreated and chemotherapy-recovered OC, we developed laminin- and collagen-rich ECM-reconstituted cell culture models amenable to studies of cell clusters that can form outgrowths. We demonstrate that ECM promotes outgrowth formation in fallopian tube non-ciliated epithelial cells (FNE) expressing mutant p53-R175H and various OC cell lines. Outgrowths were initiated by cells that had undergone outward translocation and, upon mechanical detachment, could intercalate into mesothelial cell monolayers. Electron microscopy, optical coherence tomography (OCT), and small amplitude oscillatory shear experiments revealed that high ECM concentration increased ECM fibrous network thickness and led to high shear elasticity in the ECM environment. These physical characteristics were associated with the suppression of outgrowths. A culture environment with low ECM concentration mimicked viscoelasticity of malignant peritoneal fluids (ascites) and supported cell proliferation, cell translocation, and outgrowth formation. These results highlight the importance of ECM microenvironments in modulating OC growth and could provide an additional explanation of why primary and recurrent ovarian tumors form outgrowths that protrude into the peritoneal cavity.

cancer biology↗

bioRxiv2018

NADP-dependent malic enzyme 1 participates in the abscisic acid response in Arabidopsis thaliana

Arabidopsis thaliana possesses three cytosolic (NADP-ME1-3) and one plastidic (NADP-ME4) NADP-dependent malic enzymes. NADP-ME2 and-ME4 show constitutive expression, in contrast to NADP-ME1 and-ME3, which are restricted to particular tissues. Here, we show that NADP-ME1 transcript and protein were almost undetectable during normal vegetative growth, but gradually increased and reached levels higher than those of the other isoforms in the latest stages of seed development. Accordingly, in knockout nadp-me1 mature seeds the total NADP-ME activity was significantly lower than in wild type mature seeds. The phenotypic analysis of nadp-me1 plants indicated alterations of seed viability and germination. Besides, the treatment with abscisic acid (ABA), NaCl and mannitol specifically induced the accumulation of NADP-ME1 in seedlings. In line with this, nadp-me1 plants show a weaker response of primary and lateral root length and stomatal opening to the presence of ABA.\n\nThe results suggest that NADP-ME1 plays a specialized role, linked to ABA signalling during the seed development as well as in the response to saline and osmotic stress.

plant biology↗