Pharmacological inhibition of lipid import and transport proteins in ovarian cancer
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA876913 | ENA |
REPOSITORIES: ENA
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Project description:Ovarian cancer (OC) is still the most fatal gynecological cancer due to late diagnosis when peritoneal metastasis has already occurred. OC progression requires lipid nutrients that are either synthesized endogenously in the cancer cells or imported from the surrounding host tissue. Accordingly, blockade of lipid synthesis has been shown to be a powerful strategy against OC. However, direct evidence of the role of lipid import and transport for OC growth is still largely missing. Therefore, we exposed OC cells to inhibitors of lipid uptake and transport proteins, which are typically overexpressed in OC. Our data reveal that pharmacological inhibition of these lipid handling proteins caused drug-specific, dose- and time-dependent decline of lipid-uptake, which was associated with cell growth reduction, cell cycle arrest and apoptosis indicating that OC cells are exquisitely sensitive to lipid deficiency. This dependency provides the rationale for the development of novel lipid-antimetabolic strategies against OC.
2022-12-05 | GSE212702 | GEO
Project description:Ovarian cancer (OC) is the most lethal gynecological malignancy with a 5-year survival rate of 49%. This is caused by late diagnosis when cells have already metastasized into the peritoneal cavity and to the omentum. OC progression is dependent on the availability of high-energy lipids/fatty acids (FA) provided by endogenous de novo biosynthesis and/or through import from the microenvironment. The blockade of these processes may thus represent powerful strategies against OC. While this has already been shown for inhibition of FA/lipid biosynthesis, evidence of the role of FA/lipid import/transport is still sparse. Therefore, we treated A2780 and SKOV3 OC cells with inhibitors of the lipid uptake proteins fatty acid translocase/cluster of differentiation 36 (FAT/CD36) and low-density lipoprotein (LDL) receptor (LDLR), as well as intracellular lipid transporters of the fatty acid-binding protein (FABP) family, fatty acid transport protein-2 (FATP2/SLC27A2), and ADP-ribosylation factor 6 (ARF6), which are overexpressed in OC. Proliferation was determined by formazan dye labeling/photometry and cell counting. Cell cycle analysis was performed by propidium iodide (PI) staining, and apoptosis was examined by annexin V/PI and active caspase 3 labeling and flow cytometry. RNA-seq data revealed altered stress and metabolism pathways. Overall, the small molecule inhibitors of lipid handling proteins BMS309403, HTS01037, NAV2729, SB-FI-26, and sulfosuccinimidyl oleate (SSO) caused a drug-specific, dose-/time-dependent inhibition of FA/LDL uptake, associated with reduced proliferation, cell cycle arrest, and apoptosis. Our findings indicate that OC cells are very sensitive to lipid deficiency. This dependency should be exploited for development of novel strategies against OC.
| S-EPMC9737127 | biostudies-literature
Project description:Hepatic nonvesicular cholesterol transport is critical for systemic lipid homeostasis
| PRJNA849943 | ENA
Project description:In cell models, changes in the “accessible” pool of plasma membrane (PM) cholesterol are linked with the regulation of ER sterol synthesis and metabolism by the Aster family of nonvesicular transporters. However, the relevance of such nonvesicular transport mechanisms for lipid homeostasis in vivo has not been defined. Here we reveal two physiological contexts that generate accessible PM cholesterol and engage the Aster pathway in liver: fasting and reverse cholesterol transport (RCT). During fasting, adipose tissue–derived fatty acids activate hepatocyte sphingomyelinase to liberate sequestered PM cholesterol. Aster-dependent cholesterol transport during fasting facilitates cholesteryl ester (CE) formation, cholesterol movement into bile, and VLDL production. During RCT, HDL delivers excess cholesterol to the hepatocyte PM through SR-BI. Loss of hepatic Asters impairs cholesterol movement into feces, raises plasma cholesterol levels, and causes cholesterol accumulation in peripheral tissues. These results reveal fundamental mechanisms by which Aster cholesterol flux contributes to hepatic and systemic lipid homeostasis.
2022-10-24 | GSE206278 | GEO
Project description:Mitochondrial biogenesis requires the import of >1,000 mitochondrial preproteins from the cytosol. Most studies on mitochondrial protein import are focused on the core import machinery. Whether and how the biophysical properties of substrate preproteins affect overall import efficiency is underexplored. Here, we show that protein traffic into mitochondria can be disrupted by amino acid substitutions in a single substrate preprotein. Pathogenic missense mutations in adenine nucleotide translocase 1 (Ant1), and its yeast homolog Aac2, cause the protein to accumulate along the protein import pathway, thereby obstructing general protein translocation into mitochondria. This impairs mitochondrial respiration, cytosolic proteostasis and cell viability independent of Ant1’s nucleotide transport activity. The mutations act synergistically, as double mutant Aac2/Ant1 cause severe clogging primarily at the Translocase of the Outer Membrane (TOM) complex. This confers extreme toxicity in yeast. In mice, expression of a super-clogger Ant1 variant led to neurodegeneration and an age-dependent dominant myopathy that phenocopy Ant1-induced human disease, suggesting clogging as a mechanism of disease. More broadly, this work implies the existence of uncharacterized amino acid requirements for mitochondrial carrier proteins to avoid clogging and subsequent disease.
2023-03-17 | GSE227295 | GEO
Project description:Nuclear pores are essential pathways for nuclear-cytoplasmic transport of molecules. Whether and how cells change nuclear pores to alter nuclear transport and cellular function is unknown. Here, we show that heart muscle cells (cardiomyocytes) undergo a 63% decrease in nuclear pore numbers during differentiation, which alters their response to extracellular signals. This maturation-associated decline in nuclear pore numbers per nucleus is associated with lower nuclear levels and import of Mitogen-activated Protein Kinase (MAPK) signaling proteins. Experimental reduction of nuclear pore numbers decreased nuclear import of MAPK signaling proteins. In a mouse model of high blood pressure, reduction of cardiomyocyte nuclear pore numbers reduced adverse heart remodeling and gene regulation, which reduced progression to lethal heart failure. The observed decrease in nuclear pore numbers in cardiomyocyte differentiation and resulting functional changes suggest a paradigm by which terminally differentiated cells could permanently alter their handling of information flux across the nuclear envelope and, with that, their behavior.
2022-09-26 | GSE186949 | GEO
Project description:Abnormal distribution of cellular cholesterol is associated with numerous diseases, including cardiovascular and neurodegenerative diseases. Regulated transport of cholesterol is critical for maintaining its proper distribution in the cell, yet the underlying mechanisms remain unclear. Here, we show that lipid transfer proteins, namely ORP9, OSBP, and GRAMD1s/Asters (GRAMD1a/GRAMD1b/GRAMD1c), control non-vesicular cholesterol transport at points of contact between the ER and the trans-Golgi network (TGN), thereby maintaining cellular cholesterol distribution. ORP9 localizes to the TGN via interaction between its tandem α-helices and ORP10/ORP11. ORP9 extracts PI4P from the TGN to prevent its overaccumulation and suppresses OSBP-mediated PI4P-driven cholesterol transport to the Golgi. By contrast, GRAMD1s transport excess cholesterol from the Golgi to the ER, thereby preventing its build-up. Cells lacking ORP9 exhibit accumulation of cholesterol at the Golgi, which is further enhanced by additional depletion of GRAMD1s with major accumulation in the plasma membrane. This is accompanied by chronic activation of the SREBP-2 signalling pathway. Our findings reveal the importance of regulated lipid transport at ER-Golgi contacts for maintaining cellular cholesterol distribution and homeostasis.
2023-09-24 | GSE240960 | GEO
Project description:The ARV1-encoded protein mediates sterol transport from the endoplasmic reticulum (ER) to the plasma membrane. Yeast ARV1 mutants accumulate multiple lipids in the ER and are sensitive to pharmacological modulators of both sterol and sphingolipid metabolism. Using fluorescent and electron microscopy, we demonstrate sterol accumulation, subcellular membrane expansion, elevated lipid droplet formation and vacuolar fragmentation in ARV1 mutants. Motif-based regression analysis of ARV1 deletion transcription profiles indicates activation of Hac1p, an integral component of the UPR. Accordingly, we show constitutive splicing of HAC1 transcripts, induction of a UPR reporter and elevated expression of UPR targets in ARV1 mutants. IRE1, encoding the unfolded protein sensor in the ER lumen, exhibits a lethal genetic interaction with ARV1, indicating a viability requirement for the UPR in cells lacking ARV1. Surprisingly, ARV1 mutants expressing a variant of Ire1p defective in sensing unfolded proteins are viable. Moreover these strains also exhibit constitutive HAC1 splicing that interacts with DTT-mediated perturbation of protein folding. These data suggest a component of UPR induction in arv1? strains is distinct from protein misfolding. Decreased ARV1 expression in murine macrophages also results in UPR induction, particularly up-regulation of activating transcription factor-4, C/EBP homologous protein (CHOP) and apoptosis. Cholesterol loading or inhibition of cholesterol esterification further elevated CHOP expression in ARV1 knockdown cells. Thus, loss or down-regulation of ARV1 disturbs membrane and lipid homeostasis resulting in a disruption of ER integrity, one consequence of which is induction of the UPR. Yeast strains were grown to mid-logarithmic stage (A600=0.5-0.6) for RNA extraction and hybridization on Ye6100 or S98 Affymetrix gene chips. The control array (sample name C) was carried out in duplicate. The ARV1 mutant array (sample name A) was carried out in triplicate. Both ARV1 mutants Ye6100 arrays were compared to the same control Ye6100 array. Strains represent different isolates of the same genotype, mating type and genetic background (w303). Sturley lab collection (SCY) strains include SCY328 and SCY2004 for controls and SCY820 and SCY840 for ARV1 mutants.
2011-02-17 | E-GEOD-26801 | biostudies-arrayexpress
Project description:Mitophagy is essential to maintain mitochondrial function and prevent diseases. It activates upon mitochondria depolarization, which causes PINK1 stabilization on the mitochondrial outer membrane. Strikingly, a number of conditions, including mitochondrial protein misfolding, can induce mitophagy without a loss in membrane potential. The underlying molecular details remain unclear. Here, we report that a loss of mitochondrial protein import, mediated by the pre-sequence translocase-associated motor complex PAM, is sufficient to induce mitophagy in polarized mitochondria. A genome-wide CRISPR/Cas9 screen for mitophagy inducers identifies components of the PAM complex. Protein import defects are able to induce mitophagy without a need for depolarization. Upon mitochondrial protein misfolding, PAM dissociates from the import machinery resulting in decreased protein import and mitophagy induction. Our findings extend the current mitophagy model to explain mitophagy induction upon conditions that do not affect membrane polarization, such as mitochondrial protein misfolding.
2022-08-04 | GSE207212 | GEO
Project description:During megakaryopoiesis and consecutive platelet production, megakaryocytes undergo robust cellular morphological changes which are associated with the reprogramming of signaling pathways. Moreover, it can be assumed that lipid membrane composition and signaling are strongly modified. However, the knowledge of lipid alteration during megakaryopoiesis and which pathways are involved is still lacking. Here, we use a lipid-centric multiomics approach to create a quantitative map of the megakaryocyte lipidome during maturation and proplatelet formation. Our data reveal that megakaryocyte differentiation is driven by an increased fatty acyl import and de novo lipid synthesis, resulting in the modulation towards an anionic membrane phenotype. This phenotype and the upregulation of diacylglycerols highly correlate with the activation of lipid-dependent kinases such as PKC and BTK. Using inhibitors of fatty acid import and phospholipid synthesis proved to block membrane remodeling and kinase activation and directly reduced proplatelet formation. Altogether, this study provides a framework for understanding how membrane lipid remodeling during megakaryocyte differentiation impacts kinase signaling and proplatelet formation while providing a knowledge base to exploit megakaryopoiesis.
2023-08-22 | PXD037622 | Pride