Targeting Cholesterol Metabolism Research Articles

Cholesterol Metabolism: A Potential Therapeutic Target in Glioblastoma.

Glioblastoma is a highly lethal adult brain tumor with no effective treatments. In this review, we discuss the potential to target cholesterol metabolism as a new strategy for treating glioblastomas. Twenty percent of cholesterol in the body is in the brain, yet the brain is unique among organs in that it has no access to dietary cholesterol and must synthesize it de novo. This suggests that therapies targeting cholesterol synthesis in brain tumors might render their effects without compromising cell viability in other organs. We will describe cholesterol synthesis and homeostatic feedback pathways in normal brain and brain tumors, as well as various strategies for targeting these pathways for therapeutic intervention.

Targeting cholesterol metabolism in neuroblastoma by acting on HDACs

Event Abstract Back to Event Targeting cholesterol metabolism in neuroblastoma by acting on HDACs Maria João Nunes1, 2, Daniela Costa1, Rita Mendes De Almeida1, Margarida Castro-Caldas1, 3, Maria João Gama1, 2 and Elsa Rodrigues1, 2* 1 Research Institute for Medicines (iMed.ULisboa), Portugal 2 Department of Biochemistry and Human Biology, Faculty of Pharmacy, University of Lisbon, Portugal 3 Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Portugal A wide range of brain disorders are associated with imbalances in protein acetylation levels and treatment with various histone deacetylase (HDAC) inhibitors (HDACi) has been shown to correct these deficiencies, emerging as a promising new strategy for therapeutic intervention in neurodegenerative diseases. We have demonstrated that in neuroblastoma cells HDACi dramatically increase mRNA levels of genes involved in cholesterol efflux and elimination, while decreasing the expression of genes involved in synthesis and uptake, leading to a decrease in intracellular cholesterol content. These results suggested that this class of compounds could potentially be used to modulate brain cholesterol metabolism in pathological conditions. We used primary cultures of mice neurons and astrocytes treated with the pan-HDACi trichostatin A, and with class-specific HDAC inhibitors, namely, the class I inhibitor Mocetinostat (MGCD0103) and the class II (IIa) inhibitor MC1568, to evaluate the mRNA levels of a panel of genes involved in cholesterol synthesis, up-take, transport and elimination. Although we could only partially recapitulate the results obtained in the neuroblastoma cells, we could identify class I HDACs as major modulators of neuronal cholesterol homeostasis. In addition, when comparing the expression profiles of neurons and astrocytes, we identified Mvk, Cyp46a1 and Apoe as genes that are affected by both TSA and MGCD0103 in both cells. In order to further dissect the role of class I HDACs we specifically silenced class I HDACs by transfecting TALEN specific plasmids in SH-SY5Y neuroblastoma cells. Our results point to a role of class I HDACs as therapeutic targets both in neuroblastoma and neurodegenerative disorders with disturbances in cholesterol homeostasis. Acknowledgements This work was supported by FEDER and national funds from Fundação para a Ciência e Tecnologia (FCT) (UID/DTP/04138/2013 and fellowship SFRH/BPD/95855/2013 to MJN). Keywords: cholesterol metabolism, HDACs, HDAC inhibitors, neurodegeneration, Neuroblastoma Conference: XVI Meeting of the Portuguese Society for Neuroscience (SPN2019), Lisboa, Portugal, 30 May - 1 Jun, 2019. Presentation Type: Poster presentation Topic: Cellular and Molecular Neurosciences Citation: Nunes M, Costa D, Mendes De Almeida R, Castro-Caldas M, Gama M and Rodrigues E (2019). Targeting cholesterol metabolism in neuroblastoma by acting on HDACs. Front. Cell. Neurosci. Conference Abstract: XVI Meeting of the Portuguese Society for Neuroscience (SPN2019). doi: 10.3389/conf.fncel.2019.01.00012 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 16 Apr 2019; Published Online: 27 Sep 2019. * Correspondence: Prof. Elsa Rodrigues, Research Institute for Medicines (iMed.ULisboa), Lisboa, Portugal, elsa.rodrigues@ff.ulisboa.pt Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Maria João Nunes Daniela Costa Rita Mendes De Almeida Margarida Castro-Caldas Maria João Gama Elsa Rodrigues Google Maria João Nunes Daniela Costa Rita Mendes De Almeida Margarida Castro-Caldas Maria João Gama Elsa Rodrigues Google Scholar Maria João Nunes Daniela Costa Rita Mendes De Almeida Margarida Castro-Caldas Maria João Gama Elsa Rodrigues PubMed Maria João Nunes Daniela Costa Rita Mendes De Almeida Margarida Castro-Caldas Maria João Gama Elsa Rodrigues Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Targeting lipid metabolism to overcome EMT-associated drug resistance via integrin β3/FAK pathway and tumor-associated macrophage repolarization using legumain-activatable delivery.

Epithelial-mesenchymal transition (EMT) is closely associated with the development of drug resistance. Lipid metabolism plays an important role in EMT. This work was to study the cholesterol-lowering drug simvastatin for reversing EMT-associated resistance to chemotherapy via lipid metabolism.Methods: The combination of simvastatin and paclitaxel was used to overcome the EMT-associated drug resistance. For dual-action on both cancer cells and tumor-associated macrophages (TAM), the tumor microenvironment-activatable multifunctional liposomes were developed for drug codelivery. The liposomes were modified with a hairpin-structured, activatable cell-penetrating peptide that is specifically responsive to the tumor-associated protease legumain.Results: It was revealed simvastatin can disrupt lipid rafts (cholesterol-rich domains) and suppress integrin-β3 and focal adhesion formation, thus inhibiting FAK signaling pathway and re-sensitizing the drug-resistant cancer cells to paclitaxel. Furthermore, simvastatin was able to re-polarize tumor-associated macrophages (TAM), promoting M2-to-M1 phenotype switch via cholesterol-associated LXR/ABCA1 regulation. The repolarization increased TNF-α, but attenuated TGF-β, which, in turn, remodeled the tumor microenvironment and suppressed EMT. The liposomal formulation achieved enhanced treatment efficacy.Conclusion: This study provides a promising simvastatin-based nanomedicine strategy targeting cholesterol metabolism to reverse EMT and repolarize TAM to treat drug-resistant cancer. The elucidation of the molecular pathways (cholesterol/lipid raft/integrin β3/FAK and cholesterol-associated LXR/ABCA1 regulation) for anti-EMT and the new application of simvastatin should be of clinical significance.

Abstract 2397: Intracellular cholesterol regulates the DNA damage response in inflammatory breast cancer

Abstract Purpose: Inflammatory breast cancer (IBC) is a highly aggressive form of breast cancer, and patients with IBC remain at high risk of locoregional recurrence after radiotherapy. We previously demonstrated that depleting intracellular cholesterol induces radiosensitivity in IBC cells in vitro, and that IBC patients with high levels of high-density lipoprotein (HDL) and those taking a statin, which inhibits de novo cholesterol biosynthesis, have improved locoregional control after radiotherapy. These results suggest that targeting cholesterol metabolism may improve the radiotherapeutic management of IBC. Here, we aimed to understand the molecular mechanism(s) linking cholesterol metabolism and radiation-induced DNA damage and DNA repair and to evaluate statin pharmacotherapy as a DNA repair inhibitor and radiotherapeutic adjunct in an in vivo pre-clinical model of IBC. Methods: KPL4, SUM149, SUM190, and IBC3 IBC cell lines were used to examine the effect(s) of simvastatin and human serum lipoproteins on radiation-induced DNA damage induction, DNA damage signaling, DNA damage-associated G1, intra-S, and G2/M cell cycle checkpoint activation, and DNA double strand break (DSB) repair by homologous recombination (HR) and non-homologous end joining (NHEJ). Results: We have generated multiple IBC cells lines with an integrated Traffic Light Reporter (TLR) that is capable of measuring HR and NHEJ, and demonstrate that depletion of intracellular cholesterol abrogates HR-mediated repair of DNA DSBs. We also show that intracellular cholesterol has pleiotropic effects on cell cycle distribution and DNA damage-associated cell cycle checkpoints. We also report a novel polycistronic dual bioluminescence reporter system that can robustly visualize and quantitate DNA DSB induction and repair in vitro and in vivo. Conclusions: Cholesterol is an important determinant of intrinsic radiosensitivity in IBC, and appears to regulate repair of radiation-induced DNA DSBs. Targeting cholesterol metabolism is a potential strategy to overcome IBC radioresistance and improve the prognosis for this aggressive disease. Citation Format: Shane R. Stecklein, Adam R. Wolfe, Bisrat G. Debeb, Richard A. Larson, Wendy A. Woodward. Intracellular cholesterol regulates the DNA damage response in inflammatory breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2397.

Rational Targeting of Cellular Cholesterol in Diffuse Large B-Cell Lymphoma (DLBCL) Enabled by Functional Lipoprotein Nanoparticles: A Therapeutic Strategy Dependent on Cell of Origin.

Cancer cells have altered metabolism and, in some cases, an increased demand for cholesterol. It is important to identify novel, rational treatments based on biology, and cellular cholesterol metabolism as a potential target for cancer is an innovative approach. Toward this end, we focused on diffuse large B-cell lymphoma (DLBCL) as a model because there is differential cholesterol biosynthesis driven by B-cell receptor (BCR) signaling in germinal center (GC) versus activated B-cell (ABC) DLBCL. To specifically target cellular cholesterol homeostasis, we employed high-density lipoprotein-like nanoparticles (HDL NP) that can generally reduce cellular cholesterol by targeting and blocking cholesterol uptake through the high-affinity HDL receptor, scavenger receptor type B-1 (SCARB1). As we previously reported, GC DLBCL are exquisitely sensitive to HDL NP as monotherapy, while ABC DLBCL are less sensitive. Herein, we report that enhanced BCR signaling and resultant de novo cholesterol synthesis in ABC DLBCL drastically reduces the ability of HDL NPs to reduce cellular cholesterol and induce cell death. Therefore, we combined HDL NP with the BCR signaling inhibitor ibrutinib and the SYK inhibitor R406. By targeting both cellular cholesterol uptake and BCR-associated de novo cholesterol synthesis, we achieved cellular cholesterol reduction and induced apoptosis in otherwise resistant ABC DLBCL cell lines. These results in lymphoma demonstrate that reduction of cellular cholesterol is a powerful mechanism to induce apoptosis. Cells rich in cholesterol require HDL NP therapy to reduce uptake and molecularly targeted agents that inhibit upstream pathways that stimulate de novo cholesterol synthesis, thus, providing a new paradigm for rationally targeting cholesterol metabolism as therapy for cancer.

Synthetic high-density lipoproteins as targeted monotherapy for chronic lymphocytic leukemia.

Chronic lymphocytic leukemia (CLL) remains incurable despite the introduction of new drugs. Therapies targeting receptors and pathways active specifically in malignant B cells might provide better treatment options. For instance, in B cell lymphoma, our group has previously shown that scavenger receptor type B-1 (SR-B1), the high-affinity receptor for cholesterol-rich high-density lipoproteins (HDL), is a therapeutic target. As evidence suggests that targeting cholesterol metabolism in CLL cells may have therapeutic benefit, we examined SR-B1 expression in primary CLL cells from patients. Unlike normal B cells that do not express SR-B1, CLL cells express the receptor. As a result, we evaluated cholesterol-poor synthetic HDL nanoparticles (HDL NP), known for targeting SR-B1, as a therapy for CLL. HDL NPs potently and selectively induce apoptotic cell death in primary CLL cells. HDL NPs had no effect on normal peripheral blood mononuclear cells from healthy individuals or patients with CLL. These data implicate SR-B1 as a target in CLL and HDL NPs as targeted monotherapy for CLL.

Targeting cholesterol transport in circulating melanoma cells toinhibit metastasis.

Despite recent breakthroughs in targeted- and immune-based therapies, rapid development of drug resistance remains a hurdle for the long-term treatment of patients with melanoma. Targeting metastatically spreading circulating tumor cells (CTCs) may provide an additional approach to manage melanoma. This study investigates whether targeting cholesterol transport in melanoma CTCs can retard metastasis development. Nanolipolee-007, the liposomal form of leelamine, reduced melanoma metastasis in both a novel in vitro flow system mimicking the circulating system and in experimental as well as spontaneous animal metastasis models, irrespective of the BRAF mutational status of the CTCs. Leelamine led to cholesterol trapping in lysosomes, which subsequently shut down receptor-mediated endocytosis, endosome trafficking, and inhibited the major oncogenic signaling cascades important for survival such as the AKT pathway. As pAKT is important in CTC survival, inhibition by targeting cholesterol metabolism led to apoptosis, suggesting this approach might be particularly effective for those CTCs having high levels of pAKT to aid survival in the circulation system.

V-ATPase inhibition increases cancer cell stiffness and blocks membrane related Ras signaling - a new option for HCC therapy.

Hepatocellular carcinoma (HCC) is the fifth most frequent cancer worldwide and the third leading cause of cancer-related death. However, therapy options are limited leaving an urgent need to develop new strategies. Currently, targeting cancer cell lipid and cholesterol metabolism is gaining interest especially regarding HCC. High cholesterol levels support proliferation, membrane-related mitogenic signaling and increase cell softness, leading to tumor progression, malignancy and invasive potential. However, effective ways to target cholesterol metabolism for cancer therapy are still missing. The V-ATPase inhibitor archazolid was recently shown to interfere with cholesterol metabolism. In our study, we report a novel therapeutic potential of V-ATPase inhibition in HCC by altering the mechanical phenotype of cancer cells leading to reduced proliferative signaling. Archazolid causes cellular depletion of free cholesterol leading to an increase in cell stiffness and membrane polarity of cancer cells, while hepatocytes remain unaffected. The altered membrane composition decreases membrane fluidity and leads to an inhibition of membrane-related Ras signaling resulting decreased proliferation in vitro and in vivo. V-ATPase inhibition represents a novel link between cell biophysical properties and proliferative signaling selectively in malignant HCC cells, providing the basis for an attractive and innovative strategy against HCC.

Intestinal FXR agonism promotes adipose tissue browning and reduces obesity and insulin resistance.

The systemic expression of the bile acid (BA) sensor farnesoid X receptor (FXR) has led to promising new therapies targeting cholesterol metabolism, triglyceride production, hepatic steatosis and biliary cholestasis. In contrast to systemic therapy, bile acid release during a meal selectively activates intestinal FXR. By mimicking this tissue-selective effect, the gut-restricted FXR agonist fexaramine (Fex) robustly induces enteric fibroblast growth factor 15 (FGF15), leading to alterations in BA composition, but does so without activating FXR target genes in the liver. However, unlike systemic agonism, we find that Fex reduces diet-induced weight gain, body-wide inflammation and hepatic glucose production, while enhancing thermogenesis and browning of white adipose tissue (WAT). These pronounced metabolic improvements suggest tissue-restricted FXR activation as a new approach in the treatment of obesity and metabolic syndrome.

Alzheimer's disease (AD) as a disorder of the plasma membrane

GENERAL COMMENTARY article Front. Physiol., 15 February 2013Sec. Membrane Physiology and Membrane Biophysics https://doi.org/10.3389/fphys.2013.00024

Ginger phytochemicals mitigate the obesogenic effects of a high-fat diet in mice: a proteomic and biomarker network analysis.

Natural dietary anti-obesogenic phytochemicals may help combat the rising global incidence of obesity. We aimed to identify key hepatic pathways targeted by anti-obsogenic ginger phytochemicals fed to mice. Weaning mice were fed a high-fat diet containing 6-gingerol (HFG), zerumbone (HFZ), a characterized rhizome extract of the ginger-related plant Alpinia officinarum Hance (high fat goryankang, HFGK) or no phytochemicals (high-fat control, HFC) for 6 wks and were compared with mice on a low-fat control diet (LFC). Increased adiposity in the HFC group, compared with the LFC group, was significantly (p<0.05) reduced in the HFG and HFGK groups without food intake being affected. Correlation network analysis, including a novel residuals analysis, was utilized to investigate relationships between liver proteomic data, lipid and cholesterol biomarkers and physiological indicators of adiposity. 6-Gingerol significantly increased plasma cholesterol but hepatic farnesyl diphosphate synthetase, which is involved in cholesterol biosynthesis was decreased, possibly by negative feedback. Acetyl-coenzyme A acyltransferase 1 and enoyl CoA hydratase, which participate in the β-oxidation of fatty acids were significantly (p<0.05) increased by consumption of phytochemical-supplemented diets. Dietary ginger phytochemicals target cholesterol metabolism and fatty acid oxidation in mice, with anti-obesogenic but also hypercholesterolemic consequences.