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Bar E, Fischer I, Rokach M, Elad-Sfadia G, Shirenova S, Ophir O, Trangle SS, Okun E, Barak B. Neuronal deletion of Gtf2i results in developmental microglial alterations in a mouse model related to Williams syndrome. Glia 2024; 72:1117-1135. [PMID: 38450767 DOI: 10.1002/glia.24519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 02/08/2024] [Accepted: 02/13/2024] [Indexed: 03/08/2024]
Abstract
Williams syndrome (WS) is a genetic neurodevelopmental disorder caused by a heterozygous microdeletion, characterized by hypersociability and unique neurocognitive abnormalities. Of the deleted genes, GTF2I has been linked to hypersociability in WS. We have recently shown that Gtf2i deletion from forebrain excitatory neurons, referred to as Gtf2i conditional knockout (cKO) mice leads to multi-faceted myelination deficits associated with the social behaviors affected in WS. These deficits were potentially mediated also by microglia, as they present a close relationship with oligodendrocytes. To study the impact of altered myelination, we characterized these mice in terms of microglia over the course of development. In postnatal day 30 (P30) Gtf2i cKO mice, cortical microglia displayed a more ramified state, as compared with wild type (controls). However, postnatal day 4 (P4) microglia exhibited high proliferation rates and an elevated activation state, demonstrating altered properties related to activation and inflammation in Gtf2i cKO mice compared with control. Intriguingly, P4 Gtf2i cKO-derived microglial cells exhibited significantly elevated myelin phagocytosis in vitro compared to control mice. Lastly, systemic injection of clemastine to P4 Gtf2i cKO and control mice until P30, led to a significant interaction between genotypes and treatments on the expression levels of the phagocytic marker CD68, and a significant reduction of the macrophage/microglial marker Iba1 transcript levels in the cortex of the Gtf2i cKO treated mice. Our data thus implicate microglia as important players in WS, and that early postnatal manipulation of microglia might be beneficial in treating inflammatory and myelin-related pathologies.
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Affiliation(s)
- Ela Bar
- The School of Psychological Sciences, Faculty of Social Sciences, Tel Aviv University, Tel Aviv, Israel
- The School of Neurobiology, Biochemistry & Biophysics, Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Inbar Fischer
- The Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - May Rokach
- The Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Galit Elad-Sfadia
- The School of Psychological Sciences, Faculty of Social Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Sophie Shirenova
- The Leslie and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat Gan, Israel
- The Paul Feder Laboratory on Alzheimer's Disease Research, Bar-Ilan University, Ramat Gan, Israel
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, Israel
| | - Omer Ophir
- The Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Sari Schokoroy Trangle
- The School of Psychological Sciences, Faculty of Social Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Eitan Okun
- The Leslie and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat Gan, Israel
- The Paul Feder Laboratory on Alzheimer's Disease Research, Bar-Ilan University, Ramat Gan, Israel
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, Israel
| | - Boaz Barak
- The School of Psychological Sciences, Faculty of Social Sciences, Tel Aviv University, Tel Aviv, Israel
- The Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
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Zayoud M, Vax E, Elad-Sfadia G, Barshack I, Pinkas-Kramarski R, Goldstein I. Inhibition of Ras GTPases prevents Collagen-Induced Arthritis by Reducing the Generation of Pathogenic CD4 + T Cells and the Hyposialylation of Autoantibodies. ACR Open Rheumatol 2020; 2:512-524. [PMID: 32869536 PMCID: PMC7504479 DOI: 10.1002/acr2.11169] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 07/06/2020] [Indexed: 12/30/2022] Open
Abstract
OBJECTIVE RasGTPases are master regulators of multiple intracellular signaling cascades. Perturbation of this pathway has been implicated in the pathogenesis of rheumatoid arthritis (RA). In this study we aimed to define the therapeutic potential of a novel RasGTPases inhibitor, farnesylthiosalicylate (FTS), in the preclinical mouse model of collagen-induced arthritis (CIA) and better delineate its immunomodulatory effects both ex vivo and in the mouse. METHODS We analyzed in vitro the immunomodulatory effects of FTS on various CD4+ T-cell functions such as activation, proliferation, T-helper polarization, and production of proinflammatory cytokines. Using the CIA model, we further determined the efficacy of FTS to inhibit clinical, histopathologic, and diverse immunological outcomes of arthritis. RESULTS FTS treatment of CD4+ T cells in vitro effectively targeted distinct kinases (extracellular signal-regulated kinase 1/2, p38, protein kinase B/AKT, and mammalian target of rapamycin), the production of interleukin (IL)-17A, IL-22, and granulocyte-macrophage colony-stimulating factor, and Th17 polarization. FTS therapy in the mouse CIA model significantly reduced clinical disease severity and joint inflammation/damage by histology. Importantly, FTS suppressed the in vivo induction of splenic IL-17+ IL-22+ Th17 cells and the secretion of proinflammatory cytokines. The production of pathogenic autoantibodies and their abnormal hyposialylation was significantly attenuated by FTS therapy. Importantly, in vivo generation of collagen type-II specific effector CD4+ T cells was likewise repressed by FTS therapy. CONCLUSION The RasGTPases inhibitor FTS attenuates the production of proinflammatory cytokines by in vitro-activated T cells and is a potent immunomodulatory compound in the CIA model, primarily targeting the generation of autoreactive Th17 cells and the production of autoantibodies and their subsequent pathogenic hyposialylation.
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Affiliation(s)
- Morad Zayoud
- Tel-Aviv University, Tel-Aviv, Israel.,Rambam Health Care Campus, Haifa, Israel
| | - Einav Vax
- Tel-Aviv University, Tel-Aviv, Israel.,Chaim Sheba Academic Medical Center, Ramat Gan, Israel
| | | | - Iris Barshack
- Tel-Aviv University, Tel-Aviv, Israel.,Chaim Sheba Academic Medical Center, Ramat Gan, Israel
| | | | - Itamar Goldstein
- Tel-Aviv University, Tel-Aviv, Israel.,Chaim Sheba Academic Medical Center, Ramat Gan, Israel
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Zayoud M, Marcu-Malina V, Vax E, Jacob-Hirsch J, Elad-Sfadia G, Barshack I, Kloog Y, Goldstein I. Ras Signaling Inhibitors Attenuate Disease in Adjuvant-Induced Arthritis via Targeting Pathogenic Antigen-Specific Th17-Type Cells. Front Immunol 2017; 8:799. [PMID: 28736556 PMCID: PMC5500629 DOI: 10.3389/fimmu.2017.00799] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 06/23/2017] [Indexed: 11/29/2022] Open
Abstract
The Ras family of GTPases plays an important role in signaling nodes downstream to T cell receptor and CD28 activation, potentially lowering the threshold for T-cell receptor activation by autoantigens. Somatic mutation in NRAS or KRAS may cause a rare autoimmune disorder coupled with abnormal expansion of lymphocytes. T cells from rheumatoid arthritis (RA) patients show excessive activation of Ras/MEK/ERK pathway. The small molecule farnesylthiosalicylic acid (FTS) interferes with the interaction between Ras GTPases and their prenyl-binding chaperones to inhibit proper plasma membrane localization. In the present study, we tested the therapeutic and immunomodulatory effects of FTS and its derivative 5-fluoro-FTS (F-FTS) in the rat adjuvant-induced arthritis model (AIA). We show that AIA severity was significantly reduced by oral FTS and F-FTS treatment compared to vehicle control treatment. FTS was as effective as the mainstay anti-rheumatic drug methotrexate, and combining the two drugs significantly increased efficacy compared to each drug alone. We also discovered that FTS therapy inhibited both the CFA-driven in vivo induction of Th17 and IL-17/IFN-γ producing “double positive” as well as the upregulation of serum levels of the Th17-associated cytokines IL-17A and IL-22. By gene microarray analysis of effector CD4+ T cells from CFA-immunized rats, re-stimulated in vitro with the mycobacterium tuberculosis heat-shock protein 65 (Bhsp65), we determined that FTS abrogated the Bhsp65-induced transcription of a large list of genes (e.g., Il17a/f, Il22, Ifng, Csf2, Lta, and Il1a). The functional enrichment bioinformatics analysis showed significant overlap with predefined gene sets related to inflammation, immune system processes and autoimmunity. In conclusion, FTS and F-FTS display broad immunomodulatory effects in AIA with inhibition of the Th17-type response to a dominant arthritogenic antigen. Hence, targeting Ras signal-transduction cascade is a potential novel therapeutic approach for RA.
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Affiliation(s)
- Morad Zayoud
- Sheba Cancer Research Center, Chaim Sheba Academic Medical Center, Ramat Gan, Israel.,Rheumatology Unit, Chaim Sheba Academic Medical Center, Ramat Gan, Israel.,Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Victoria Marcu-Malina
- Sheba Cancer Research Center, Chaim Sheba Academic Medical Center, Ramat Gan, Israel.,Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Einav Vax
- Sheba Cancer Research Center, Chaim Sheba Academic Medical Center, Ramat Gan, Israel.,Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Jasmine Jacob-Hirsch
- Sheba Cancer Research Center, Chaim Sheba Academic Medical Center, Ramat Gan, Israel
| | - Galit Elad-Sfadia
- Department of Neurobiology, The George S. Wise Faculty of Life Sciences & Sagol School of Neuroscience, Tel-Aviv University, Tel-Aviv, Israel
| | - Iris Barshack
- Institute of Pathology, Chaim Sheba Academic Medical Center, Ramat Gan, Israel
| | - Yoel Kloog
- Department of Neurobiology, The George S. Wise Faculty of Life Sciences & Sagol School of Neuroscience, Tel-Aviv University, Tel-Aviv, Israel
| | - Itamar Goldstein
- Sheba Cancer Research Center, Chaim Sheba Academic Medical Center, Ramat Gan, Israel.,Rheumatology Unit, Chaim Sheba Academic Medical Center, Ramat Gan, Israel.,Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
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Schmukler E, Wolfson E, Haklai R, Elad-Sfadia G, Kloog Y, Pinkas-Kramarski R. Chloroquine synergizes with FTS to enhance cell growth inhibition and cell death. Oncotarget 2014; 5:173-84. [PMID: 24368422 PMCID: PMC3960199 DOI: 10.18632/oncotarget.1500] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
The Ras family of small GTPases transmits extracellular signals that regulate cell growth, differentiation, motility and death. Ras signaling is constitutively active in a large number of human cancers. Ras can also regulate autophagy by affecting several signaling pathways including the mTOR pathway. Autophagy is a process that regulates the balance between protein synthesis and protein degradation. It is important for normal growth control, but may be defective in diseases. Previously, we have shown that Ras inhibition by FTS induces autophagy, which partially protects cancer cells and may limit the use of FTS as an anti-cancer drug. Since FTS is a non toxic drug we hypothesized that FTS and chloroquine (an autophagy inhibitor) will synergize in cell growth inhibition and cell death. Thus, in the present study, we explored the mechanism of each individual drug and their combined action. Our results demonstrate that in HCT-116 and in Panc-1 cells, FTS induces autophagy, which can be inhibited by chloroquine. Furthermore, the combined treatment synergistically decreased the number of viable cells. Interestingly, the combined treatment enhanced apoptotic cell death as indicated by increased sub-G1 cell population, increased Hoechst staining, activation of caspase 3, decrease in survivin expression and release of cytochrome c. Thus, chloroquine treatment may promote FTS-mediated inhibition of tumor cell growth and may stimulate apoptotic cell death.
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Affiliation(s)
- Eran Schmukler
- Department of Neurobiology. Tel-Aviv University, Ramat-Aviv, Israel
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Kloog Y, Haklai R, Elad-Sfadia G. Abstract B40: Blocking Ras chaperons for cancer therapy. Mol Cancer Res 2014. [DOI: 10.1158/1557-3125.rasonc14-b40] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
We have previously developed a new concept and a new class of Ras inhibitors that affect specifically the active forms of Ras. This concept is based on the knowledge that the farnesyl moiety common to all Ras proteins might not only serve as a lipophilic lipid anchor but also confer functional specificity on Ras. This raised the possibility that the farnesyl group may act as part of a recognition unit for specific anchorage lipids or protein(s) that interact with Ras in the cell membrane. Such binding partners of Ras have been identified where it was shown that galectin-1 and galectin-3 discovered first as lectin binding proteins, act respectively as specific binding partners of farnesylated active H-Ras and K-Ras. Recently Nucleoline was identified as a specific chaperon of active N-Ras. The galectins possess a putative hydrophobic binding pocket-the putative farnesyl binding site. Galectin-1 was shown to drive H-Ras.GTP nanocluster formation and to be an integral component of the H-Ras-GTP nanocluster, a site at which Raf is activated. Similarly, galectin-3 drives K-Ras.GTP nanoclustring and robust K-Ras signaling. Ras signaling to ERK is strongly diminished in Galectin -3 knockout MEFS and in thyroid cancer cells that lack Galectin - 3. Together these findings mark the farnesyl-binding pockets as outstanding targets for Ras directed therapy, assuming that compounds that would block such sites will act as Ras inhibitors. The Ras inhibitor, S-trans-trans farnesylthiosalicylic acid (Salirasib, FTS) was indeed designed to mimic the farnesyl moiety in the carboxy terminal of Ras and was found to induce accelerated dislodgement of Ras from the cell membrane and subsequently degradation of the protein. FTS was also found to be highly efficient in inhibiting growth of many types of cancer cell lines that exhibit high Ras.GTP levels both, in vitro and in vivo. More recent phase 2 clinical trials showed that oral Salirasib treatment of pancreatic and of non-small-lung cancer patients increased significantly survival of the patients with no toxic effects. We propose to use Salirasib for the treatment of pancreatic and of non-small-lung carcinoma.
Note: This abstract was not presented at the conference.
Citation Format: Yoel Kloog, Roni Haklai, Galit Elad-Sfadia. Blocking Ras chaperons for cancer therapy. [abstract]. In: Proceedings of the AACR Special Conference on RAS Oncogenes: From Biology to Therapy; Feb 24-27, 2014; Lake Buena Vista, FL. Philadelphia (PA): AACR; Mol Cancer Res 2014;12(12 Suppl):Abstract nr B40. doi: 10.1158/1557-3125.RASONC14-B40
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Hameiri-Grossman M, Porat-Klein A, Cohen IJ, Ash S, Kloog Y, Haklai R, Elad-Sfadia G, Weizman A, Yaniv I, Avigad S. Abstract A76: Ras pathway and HIF-1α contribute to the aggressiveness of Ewing sarcoma. Cancer Res 2014. [DOI: 10.1158/1538-7445.pedcan-a76] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Aim: Ewing sarcoma (ES) is the second most common and aggressive primary malignant bone tumor in children and adolescents. The hallmarks of the tumor are specific translocations; the most frequent involves the EWS gene on chromosome 22 and the FLI-1 gene on chromosome 11. Our aim was to identify microRNAs (miRs) and genes involved in the aggressiveness of ES. Out of the miRs located on these chromosomes, 3 belong to the let-7 family.
Methods: We evaluated the expression levels of hsa-let-7a and hsa-let-7b by RQ-PCR in 57 primary ES tumors. We measured the protein levels of p-ERK, HIF-1a and EWS-FLI-1 following transfection with let-7a, let-7b or HIF-1a . The effect of a Ras inhibitor was evaluated in vitro and in vivo.
Results: In the group of patients with localized disease, a significant correlation with outcome was observed. Progression free survival (PFS) at ten years for patients with high hsa-let-7b expression was 62% versus 29% for those with low hsa-let-7b expression level (p=0.029). Multivariate Cox regression analysis identified expression of let-7b as an independent prognostic factor in ES, with a 4.4 fold increased risk of relapse (p=0.021).
hsa-let-7 is known to be a negative regulator of the RAS oncogene. Positive p-ERK immuno-staining was detected in 31 out of the 45 (69%) tumors analyzed, and a significant inverse correlation was identified between hsa-let-7a and p-ERK (p=0.037).
One of the target genes of RAS is Hypoxia inducible factor 1 (HIF-1). We detected a high level of HIF-1α protein in ES cell lines, under normoxic conditions, which did not change following induced hypoxia. This implies for a mechanism that mimics hypoxia and probably contributes to the high frequency of metastasis and thereby aggressiveness of this tumor.
Following transfection with hsa-let-7a and hsa-let-7b mimics (overexpression) the levels of RAS, p-ERK, HIF-1α and EWS-FLI-1 proteins were significantly reduced (60%, p=0.0019, 52%, p=0.003, 45%, p=0.0028 and 38%, p=0.006, respectively).
Silencing of HIF-1α resulted in a decrease of 61% of EWS-FLI-1, suggesting that HIF-1α regulates EWS-FLI-1, and we were able to show that HIF-1α directly binds EWS promoter. This was accompanied by a reduction of 32% (p=0.009) in cell proliferation rate and by a significant decrease of 36% (p=0.0013) in cell migration ability. Using a RAS inhibitor, Salirasib, we observed a significant decrease of HIF-1α and EWS-FLI-1 protein levels in both in-vitro and in-vivo settings. In addition, a significant inhibition of tumor growth was demonstrated in the treated animals.
Conclusions: These results imply that Ras and HIF-1α might contribute to the high frequency of metastasis and thereby aggressiveness of ES tumors. The reduction in tumor burden in a mouse model of ES following Salirasib treatment, demonstrates the therapeutic potential of this RAS inhibitor in ES.
Citation Format: Michal Hameiri-Grossman, Adi Porat-Klein, Ian J. Cohen, Shifra Ash, Yoel Kloog, Ronit Haklai, Galit Elad-Sfadia, Avraham Weizman, Isaac Yaniv, Smadar Avigad. Ras pathway and HIF-1α contribute to the aggressiveness of Ewing sarcoma. [abstract]. In: Proceedings of the AACR Special Conference on Pediatric Cancer at the Crossroads: Translating Discovery into Improved Outcomes; Nov 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;74(20 Suppl):Abstract nr A76.
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Affiliation(s)
| | | | - Ian J. Cohen
- 2Schneider Children's Medical Center of Israel, Petah Tikva, Israel,
| | - Shifra Ash
- 2Schneider Children's Medical Center of Israel, Petah Tikva, Israel,
| | | | | | | | | | - Isaac Yaniv
- 2Schneider Children's Medical Center of Israel, Petah Tikva, Israel,
| | - Smadar Avigad
- 2Schneider Children's Medical Center of Israel, Petah Tikva, Israel,
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Neeman R, Abramovitch S, Sharvit E, Elad-Sfadia G, Haklai R, Kloog Y, Reif S. Vitamin D and S-farnesylthiosalicylic acid have a synergistic effect on hepatic stellate cells proliferation. Dig Dis Sci 2014; 59:2462-9. [PMID: 24942325 DOI: 10.1007/s10620-014-3207-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 05/05/2014] [Indexed: 01/07/2023]
Abstract
BACKGROUND Hepatic stellate cells (HSCs) have a key role in the formation of hepatic fibrosis. The active form of vitamin D, 1,25(OH)2D3, has been found to have antiproliferative and antifibrotic effects in various tissues including liver. Farnesylthiosalicylic acid (FTS), a novel Ras antagonist, was also found to inhibit hepatic fibrosis. AIMS The purpose of this study was to examine the antiproliferative and antifibrotic effects of the combined treatment of 1,25(OH)2D3 and FTS on primary cultured HSCs. METHODS Primary HSCs, isolated from rat's livers, were treated with 1,25(OH)2D3, FTS or a combination of both. Proliferation was assessed by bromodeoxyuridine. Expression of p-ERK, ERK, Ras-GTP, total-Ras, CyclinD1 and fibrotic markers was measured by western blotting analysis and real-time PCR. Cytotoxicity was assessed by lactate dehydrogenase method. RESULTS The combined treatment inhibited HSCs proliferation by threefold. The effect was synergistic and non-cytotoxic. In concordance, the combined treatment suppressed CyclinD1 expression by ~2-fold, whereas 1,25(OH)2D3 or FTS alone showed a significantly lower inhibitory effect. The effect of the combined treatment on CyclinD1 expression was mediated via Ras-GTP and p-ERK signal transduction pathway. The effect on fibrotic markers showed that 1,25(OH)2D3 decreased collagen Iα1 expression by ~40%, FTS by ~50% and the combined treatment by ~60%. 1,25(OH)2D3 inhibited tissue inhibitor of metalloproteinases-1 (TIMP-1) expression by 20%. FTS alone or 1,25(OH)2D3 + FTS inhibited TIMP-1 expression by 60%. FTS inhibited transforming growth factor-β (TGF-β) expression by 25%, while 1,25(OH)2D3 had no effect. CONCLUSION Although the combination of 1,25(OH)2D3 and FTS did not demonstrate an additive antifibrotic effect, it showed a synergistic antiproliferative effect on primary HSCs. Therefore, the combined treatment may have a potential therapeutic value in the initiation of fibrotic process.
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Affiliation(s)
- Rina Neeman
- Sackler Faculty of Medicine, Tel Aviv University, Tel-Aviv, Israel,
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Abstract
The Ras inhibitor S-trans,trans-farnesylthiosalicylic acid (FTS, Salirasib®) interferes with Ras membrane interactions that are crucial for Ras-dependent signaling and cellular transformation. FTS had been successfully evaluated in clinical trials of cancer patients. Interestingly, its effect is mediated by targeting Ras chaperones that serve as key coordinators for Ras proper folding and delivery, thus offering a novel target for cancer therapy. The development of new FTS analogs has revealed that the specific modifications to the FTS carboxyl group by esterification and amidation yielded compounds with improved growth inhibitory activity. When FTS was combined with additional therapeutic agents its activity toward Ras was significantly augmented. FTS should be tested not only in cancer but also for genetic diseases associated with abnormal Ras signaling, as well as for various inflammatory and autoimmune disturbances, where Ras plays a major role. We conclude that FTS has a great potential both as a safe anticancer drug and as a promising immune modulator agent.
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Affiliation(s)
- Yoel Kloog
- Department of Neurobiology, Faculty of Life Sciences, Tel-Aviv University, Ramat-Aviv, Israel.
| | - Galit Elad-Sfadia
- Department of Neurobiology, Faculty of Life Sciences, Tel-Aviv University, Ramat-Aviv, Israel
| | - Roni Haklai
- Department of Neurobiology, Faculty of Life Sciences, Tel-Aviv University, Ramat-Aviv, Israel
| | - Adam Mor
- Department of Medicine, New York University School of Medicine, New York, New York, USA; Department of Pathology, New York University School of Medicine, New York, New York, USA
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Mashiach-Farkash E, Rak R, Elad-Sfadia G, Haklai R, Carmeli S, Kloog Y, Wolfson HJ. Computer-based identification of a novel LIMK1/2 inhibitor that synergizes with salirasib to destabilize the actin cytoskeleton. Oncotarget 2013; 3:629-39. [PMID: 22776759 PMCID: PMC3442289 DOI: 10.18632/oncotarget.525] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Neurofibromin regulates cell motility via three distinct GTPase pathways acting through two different domains, the Ras GTPase-activating protein-related domain (GRD) and the pre-GRD domain. First, the GRD domain inhibits Ras-dependent changes in cell motility through the mitogen activated protein cascade. Second, it also regulates Rho-dependent (Ras-independent) changes by activating LIM kinase 2 (LIMK2), an enzyme that phosphorylates and inactivates cofilin (an actin-depolymerizing factor). Third, the pre-GRD domain acts through the Rac1 GTPase, that activate the P21 activated kinase 1 (PAK1)-LIMK1-cofilin pathway. We employed molecular modeling to identify a novel inhibitor of LIMK1/2. The active sites of an ephrin-A receptor (EphA3) and LIMK2 showed marked similarity (60%). On testing a known inhibitor of EphA3, we found that it fits to the LIMK1/2-ATP binding site and to the latter's substrate-binding pockets. We identified a similar compound, T56-LIMKi, and found that it inhibits LIMK1/2 kinase activities. It blocked the phosphorylation of cofilin which led to actin severance and inhibition of tumor cell migration, tumor cell growth, and anchorage-independent colony formation in soft agar. Because modulation of LIMK by neurofibromin is not affected by the Ras inhibitor Salirasib, we examined the combined effect of Salirasib and T56-LIMKi each of which can affect cell motility by a distinct pathway. We found that their combined action on cell proliferation and stress-fiber formation in neurofibromin-deficient cells was synergistic. We suggest that this drug combination may be developed for treatment of neurofibromatosis and cancer.
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Affiliation(s)
- Efrat Mashiach-Farkash
- The Blavatnik School of Computer Science, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel-Aviv University, Tel Aviv, Israel
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Nevo Y, Aga-Mizrachi S, Elmakayes E, Yanay N, Ettinger K, Elbaz M, Brunschwig Z, Dadush O, Elad-Sfadia G, Haklai R, Kloog Y, Chapman J, Reif S. The Ras antagonist, farnesylthiosalicylic acid (FTS), decreases fibrosis and improves muscle strength in dy/dy mouse model of muscular dystrophy. PLoS One 2011; 6:e18049. [PMID: 21445359 PMCID: PMC3062565 DOI: 10.1371/journal.pone.0018049] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Accepted: 02/23/2011] [Indexed: 12/01/2022] Open
Abstract
The Ras superfamily of guanosine-triphosphate (GTP)-binding proteins regulates a diverse spectrum of intracellular processes involved in inflammation and fibrosis. Farnesythiosalicylic acid (FTS) is a unique and potent Ras inhibitor which decreased inflammation and fibrosis in experimentally induced liver cirrhosis and ameliorated inflammatory processes in systemic lupus erythematosus, neuritis and nephritis animal models. FTS effect on Ras expression and activity, muscle strength and fibrosis was evaluated in the dy2J/dy2J mouse model of merosin deficient congenital muscular dystrophy. The dy2J/dy2J mice had significantly increased RAS expression and activity compared with the wild type mice. FTS treatment significantly decreased RAS expression and activity. In addition, phosphorylation of ERK, a Ras downstream protein, was significantly decreased following FTS treatment in the dy2J/dy2J mice. Clinically, FTS treated mice showed significant improvement in hind limb muscle strength measured by electronic grip strength meter. Significant reduction of fibrosis was demonstrated in the treated group by quantitative Sirius Red staining and lower muscle collagen content. FTS effect was associated with significantly inhibition of both MMP-2 and MMP-9 activities. We conclude that active RAS inhibition by FTS was associated with attenuated fibrosis and improved muscle strength in the dy2J/dy2J mouse model of congenital muscular dystrophy.
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Affiliation(s)
- Yoram Nevo
- Pediatric Neuromuscular Laboratory and the Neuropediatric Unit, Hadassah Hebrew University Hospital, Jerusalem, Israel.
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Farin K, Schokoroy S, Haklai R, Cohen-Or I, Elad-Sfadia G, Reyes-Reyes ME, Bates PJ, Cox AD, Kloog Y, Pinkas-Kramarski R. Oncogenic synergism between ErbB1, nucleolin, and mutant Ras. Cancer Res 2011; 71:2140-51. [PMID: 21257709 DOI: 10.1158/0008-5472.can-10-2887] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Alterations in the ErbB family of growth factor receptors, their signaling components, and mutational activation of Ras proteins are major contributors to malignant transformation. Recently, mutant Ras was shown to be capable of activating ErbB receptors in a ligand-independent manner. Furthermore, it was observed that nucleolin, a transcriptional regulator and ribosome biogenesis factor, can bind both K-Ras and the cytoplasmic tail of ErbB receptors to enhance ErbB receptor activation. However, the functional significance of these interactions to cancer pathogenesis has not been probed. Here, we show that endogenous nucleolin interacts simultaneously in vivo with endogenous Ras and ErbB1 (EGFR) in cancer cells. The C-terminal 212 amino acids of nucleolin were determined to be sufficient to interact with ErbB1 and all Ras protein isoforms (H-, N-, and K-Ras). Nucleolin partially colocalizes with Ras at the plasma membrane. Moreover, activated but not wild-type Ras facilitates nucleolin interaction with ErbB1 and stabilizes ErbB1 receptor levels. Most importantly, these three oncogenes synergistically facilitate anchorage-independent cell growth in vitro and tumor growth in vivo. Our findings suggest strategies to target nucleolin as a general approach to inhibiting ErbB- and Ras-driven cancers.
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Affiliation(s)
- Keren Farin
- Department of Neurobiology, Tel-Aviv University, Ramat-Aviv, Israel
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12
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Rotshenker S, Reichert F, Gitik M, Haklai R, Elad-Sfadia G, Kloog Y. Galectin-3/MAC-2, Ras and PI3K activate complement receptor-3 and scavenger receptor-AI/II mediated myelin phagocytosis in microglia. Glia 2009; 56:1607-13. [PMID: 18615637 DOI: 10.1002/glia.20713] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The removal of degenerated myelin is essential for repair in Wallerian degeneration that follows traumatic injury to axons and in autoimmune demyelinating diseases (e.g., multiple sclerosis). Microglia can remove degenerated myelin through phosphatidylinositol-3-kinase (PI3K)-dependent phagocytosis mediated by complement receptor-3 (CR3/MAC-1) and scavenger receptor-AI/II (SRAI/II). Paradoxically, these receptors are expressed in microglia after injury but myelin is not phagocytosed. Additionally, Galectin-3/MAC-2 is expressed in microglia that phagocytose but not in microglia that do not phagocytose, suggesting that Galectin-3/MAC-2 is instrumental in activating phagocytosis. S-trans, trans-farnesylthiosalicylic (FTS), which inhibits Galectin-3/MAC-2 dependent activation of PI3K through Ras, inhibited phagocytosis. K-Ras-GTP levels and PI3K activity increased during normal phagocytosis and decreased during FTS-inhibited phagocytosis. Galectin-3/MAC-2, which binds and stabilizes active Ras, coimmunoprecipitated with Ras and levels of the coimmunoprecipitate increased during normal phagocytosis. A role for Galectin-3/MAC-2 dependent activation of PI3K through Ras, mostly K-Ras, is thus suggested. An explanation may thus be offered for deficient phagocytosis by microglia that express CR3/MAC-1 and SRAI/II without Galectin-3/MAC-2 and efficient phagocytosis when CR3/MAC-1 and SRAI/II are co-expressed with Galectin-3/MAC-2.
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Affiliation(s)
- Shlomo Rotshenker
- Department of Anatomy and Cell Biology, Hebrew University Faculty of Medicine, and the Eric Roland Center for Neurodegenerative Diseases, Jerusalem, Israel.
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13
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Zundelevich A, Elad-Sfadia G, Haklai R, Kloog Y. Suppression of lung cancer tumor growth in a nude mouse model by the Ras inhibitor salirasib (farnesylthiosalicylic acid). Mol Cancer Ther 2007; 6:1765-73. [PMID: 17541036 DOI: 10.1158/1535-7163.mct-06-0706] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Aberrant Ras pathway functions contribute to the malignant phenotype of lung cancers. Inhibitors of Ras might therefore be considered as potential drugs for lung cancer therapy. Here, we show that the Ras inhibitor farnesylthiosalicylic acid (salirasib) inhibits proliferation of human lung cancer cells harboring a mutated K-ras gene (A549, H23, or HTB54) or overexpressing a growth factor receptor (H1299 or HTB58) and enhances the cytotoxic effect of the chemotherapeutic drug gemcitabine. Salirasib inhibited active K-Ras in A549 cells, reversed their transformed morphology, and inhibited their anchorage-independent growth in vitro. Tumor growth in A549 and HTB58 cell nude mouse models was inhibited by i.p. administration of salirasib. P.o. formulated salirasib also inhibited A549 cell tumor growth. Our results suggest that p.o. salirasib may be considered as a potential treatment for lung cancer therapy.
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Affiliation(s)
- Adi Zundelevich
- Department of Neurobiochemistry, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
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14
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Haklai R, Elad-Sfadia G, Egozi Y, Kloog Y. Orally administered FTS (salirasib) inhibits human pancreatic tumor growth in nude mice. Cancer Chemother Pharmacol 2007; 61:89-96. [PMID: 17909812 DOI: 10.1007/s00280-007-0451-6] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2006] [Accepted: 02/27/2007] [Indexed: 10/23/2022]
Abstract
BACKGROUND S-trans,trans-farnesylthiosalicylic acid (salirasib, FTS) is a synthetic small molecule that acts as a potent Ras inhibitor. Salirasib inhibits specifically both oncogenically activated Ras and growth factor receptor-mediated Ras activation, resulting in the inhibition of Ras-dependent tumor growth. The objectives of this study were to develop a sensitive LC-MS/MS assay for determination of FTS in plasma, to assess the bioavailabilty of FTS after oral administration to mice, and then to examine the efficacy of orally administered FTS for inhibition of tumor growth in a nude mouse model. METHODS FTS was isolated from mouse plasma by liquid chromatography on a Columbus 5-mum particle size, 50 x 2 mm id column with a methanol/5 mM ammonium acetate (80/20) mobile phase (isocratic elution) at a flow rate of 0.3 ml/min. MS/MS was performed on a PE Sciex API 365 with Turbo Ion Spray as interface and negative ion ionization; parent ion (m/z): 357.2; daughter ion (m/z) 153.2; retention time 2.3 min. For plasma analysis, the amount of analyte in each sample was calculated by comparing response of the analyte in that sample to a nine-point standard curve linear over the range 3-1000 ng/ml. Pharmacokinetic studies were performed in mice following intraperitoneal dosing (20 mk/kg in PBS) or oral dosing (40 mg/kg in either 0.5% aqueous CMC or corn oil). Panc-1 tumor growth in nude mice was determined following daily oral dosing with FTS in 0.5% CMC (40, 60, or 80 mg/kg), or in combination with weekly gemcitabine (30 mg/kg). RESULTS Salirasib was readily detected in mouse plasma by LC-MS/MS at a detection limit of 3 ng/ml. For each route of administration, t (max) was 1 h and t (1/2) ranged from 1.86 to 2.66 h. Compared to IP administration, the oral bioavailabilty of FTS was 69.5% for oral CMC and 55% for oral corn oil suspensions, while clearance and volume of distribution were higher in both oral preparations. The orally administered salirasib inhibited panc-1 tumor growth in a dose dependent manner (67% reduction in tumor weight at the highest dose, P < 0.002 vs. control, n = 10 mice per group) and at a 40 mg/kg daily dose was synergistic with gemcitabine (83% increase in survival rate, n = 8 mice per group). CONCLUSIONS Salirasib exhibits good bioavailabilty after oral administration, as determined by a highly sensitive method for quantification in plasma. The orally available Ras inhibitor salirasib inhibited growth in nude mice, and may thus be considered for clinical trials.
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Affiliation(s)
- Roni Haklai
- Department of Neurobiochemistry, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 69978, Israel
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15
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Beiner ME, Niv H, Haklai R, Elad-Sfadia G, Kloog Y, Ben-Baruch G. Ras antagonist inhibits growth and chemosensitizes human epithelial ovarian cancer cells. Int J Gynecol Cancer 2006; 16 Suppl 1:200-6. [PMID: 16515591 DOI: 10.1111/j.1525-1438.2006.00508.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The objective of this article was to determine whether human ovarian carcinoma cells (OVCAR-3) express significant amounts of Ras oncogene and active Ras-guanosine triphosphate (GTP) and, if so, whether the Ras inhibitor farnesyl thiosalicylic acid (FTS) inhibits their growth and chemosensitizes them to cisplatin. We assayed Ras and Ras-GTP in OVCAR-3 cells before and after FTS treatment. The effect of FTS on OVCAR-3 cell growth was assessed in terms of cell number. Because the OVCAR-3 cell line was derived from a patient who was refractory to cisplatin, we examined whether FTS enables cisplatin to induce death of these cells. Significant amounts of Ras and active Ras-GTP were expressed by OVCAR-3 cells and were reduced by 40% by FTS. FTS inhibited OVCAR-3 cell growth in a dose-dependent manner. When combined with cisplatin, FTS reduced the number of OVCAR-3 cells by 80%, demonstrating synergism between FTS and cisplatin. FTS, at a concentration range that allows downregulation of Ras and Ras-GTP in OVCAR-3 cells, also chemosensitizes these cells and inhibits their growth. These results suggest that ovarian carcinomas might respond well to Ras inhibition, both alone and when combined with cisplatin. The combined treatment would allow the use of smaller doses of chemotherapy, resulting in decreased cytotoxicity.
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Affiliation(s)
- M E Beiner
- Department of Gynecologic Oncology, Sheba Medical Center, Tel-Hashomer, Israel.
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16
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Ashery U, Yizhar O, Rotblat B, Elad-Sfadia G, Barkan B, Haklai R, Kloog Y. Spatiotemporal organization of Ras signaling: rasosomes and the galectin switch. Cell Mol Neurobiol 2006; 26:471-95. [PMID: 16691442 DOI: 10.1007/s10571-006-9059-3] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2006] [Accepted: 03/14/2006] [Indexed: 12/31/2022]
Abstract
1. Ras signaling and oncogenesis depend on the dynamic interplay of Ras with distinctive plasma membrane (PM) microdomains and various intracellular compartments. Such interaction is dictated by individual elements in the carboxy-terminal domain of the Ras proteins, including a farnesyl isoprenoid group, sequences in the hypervariable region (hvr)-linker, and palmitoyl groups in H/N-Ras isoforms. 2. The farnesyl group acts as a specific recognition unit that interacts with prenyl-binding pockets in galectin-1 (Gal-1), galectin-3 (Gal-3), and cGMP phosphodiesterase delta. This interaction appears to contribute to the prolongation of Ras signals in the PM, the determination of Ras effector usage, and perhaps also the transport of cytoplasmic Ras. Gal-1 promotes H-Ras signaling to Raf at the expense of phosphoinositide 3-kinase (PI3-K) and Ral guanine nucleotide exchange factor (RalGEF), while galectin-3 promotes K-Ras signaling to both Raf and PI3-K. 3. The hvr-linker and the palmitates of H-Ras and N-Ras determine the micro- and macro-localizations of these proteins in the PM and in the Golgi, as well as in 'rasosomes', randomly moving nanoparticles that carry palmitoylated Ras proteins and their signal through the cytoplasm.4. The dynamic compartmentalization of Ras proteins contributes to the spatial organization of Ras signaling, promotes redistribution of Ras, and provides an additional level of selectivity to the signal output of this regulatory GTPase.
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Affiliation(s)
- Uri Ashery
- Department of Neurobiochemistry, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
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17
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Beiner ME, Niv H, Haklai R, Elad-Sfadia G, Kloog Y, Ben-Baruch G. Ras antagonist inhibits growth and chemosensitizes human epithelial ovarian cancer cells. Int J Gynecol Cancer 2006. [DOI: 10.1136/ijgc-00009577-200602001-00032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
The objective of this article was to determine whether human ovarian carcinoma cells (OVCAR-3) express significant amounts of Ras oncogene and active Ras–guanosine triphosphate (GTP) and, if so, whether the Ras inhibitor farnesyl thiosalicylic acid (FTS) inhibits their growth and chemosensitizes them to cisplatin. We assayed Ras and Ras-GTP in OVCAR-3 cells before and after FTS treatment. The effect of FTS on OVCAR-3 cell growth was assessed in terms of cell number. Because the OVCAR-3 cell line was derived from a patient who was refractory to cisplatin, we examined whether FTS enables cisplatin to induce death of these cells. Significant amounts of Ras and active Ras-GTP were expressed by OVCAR-3 cells and were reduced by 40% by FTS. FTS inhibited OVCAR-3 cell growth in a dose-dependent manner. When combined with cisplatin, FTS reduced the number of OVCAR-3 cells by 80%, demonstrating synergism between FTS and cisplatin. FTS, at a concentration range that allows downregulation of Ras and Ras-GTP in OVCAR-3 cells, also chemosensitizes these cells and inhibits their growth. These results suggest that ovarian carcinomas might respond well to Ras inhibition, both alone and when combined with cisplatin. The combined treatment would allow the use of smaller doses of chemotherapy, resulting in decreased cytotoxicity.
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18
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Elad-Sfadia G, Haklai R, Balan E, Kloog Y. Galectin-3 augments K-Ras activation and triggers a Ras signal that attenuates ERK but not phosphoinositide 3-kinase activity. J Biol Chem 2004; 279:34922-30. [PMID: 15205467 DOI: 10.1074/jbc.m312697200] [Citation(s) in RCA: 223] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Depending on the cellular context, Ras can activate characteristic effectors by mechanisms still poorly understood. Promotion by galectin-1 of Ras activation of Raf-1 but not of phosphoinositide 3-kinase (PI3-K) is one such mechanism. In this report, we describe a mechanism controlling selectivity of K-Ras4B (K-Ras), the most important Ras oncoprotein. We show that galectin-3 acts as a selective binding partner of activated K-Ras. Galectin-3 co-immunoprecipitated significantly better with K-Ras-GTP than with K-Ras-GDP, H-Ras, or N-Ras and colocalized with green fluorescent protein-K-Ras(G12V), not with green fluorescent protein-H-Ras(G12V), in the cell membrane. Co-transfectants of K-Ras/galectin-3, but not of H-Ras/galectin-3, exhibited enhanced and prolonged epidermal growth factor-stimulated increases in Ras-GTP, Raf-1 activity, and PI3-K activity. Extracellular signal-regulated kinase (ERK) activity, however, was attenuated in K-Ras/galectin-3 and in K-Ras(G12V)/galectin-3 co-transfectants. Galectin-3 antisense RNA inhibited the epidermal growth factor-stimulated increase in K-Ras-GTP but enhanced ERK activation and augmented K-Ras(G12V) transformation activity. Thus, unlike galectin-1, which prolongs Ras activation of ERK and inhibits PI3-K, K-Ras-GTP/galectin-3 interactions promote, in addition to PI3-K and Raf-1 activation, a third inhibitory signal that attenuates active ERK. These experiments established a novel and specific mechanism controlling the duration and selectivity of signals of active K-Ras, which is extremely important in many human tumors.
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Affiliation(s)
- Galit Elad-Sfadia
- Department of Neurobiochemistry, The George S. Wise Faculty of Life Sciences, Tel-Aviv University, 69978 Tel-Aviv, Israel
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19
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George J, Sack J, Barshack I, Keren P, Goldberg I, Haklai R, Elad-Sfadia G, Kloog Y, Keren G. Inhibition of Intimal Thickening in the Rat Carotid Artery Injury Model by a Nontoxic Ras Inhibitor. Arterioscler Thromb Vasc Biol 2004; 24:363-8. [PMID: 14670932 DOI: 10.1161/01.atv.0000112021.98971.f0] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Neointimal formation with and without previous vascular injury is common after balloon dilation and in transplant arteriosclerosis. It involves proliferation and migration of medial smooth muscle cells and inflammation, processes that are regulated by Ras proteins and their down-stream effectors. Farnesylthiosalicylate (FTS) is a Ras inhibitor that interferes with Ras membrane anchorage and affects Ras proteins in their active state. In the present study, we tested the hypothesis that systemic administration of FTS will suppress intimal thickening in the rat carotid injury model. METHODS AND RESULTS The effects of FTS on rat vascular smooth muscle cells (VSMC) and splenocytes proliferation were evaluated in vitro. The in vivo effects of FTS on the neointima of balloon-injured male Wistar rats, treated daily for 2 weeks with FTS (5 mg/kg weight, intraperitoneally) were evaluated by determination of Ras, Ras-GTP, and active ERK levels (3 days after injury), and by quantitative determination of the extent of intimal thickening and immunohistochemistry for Ras, iNOS, NFkB, and Ki-67 (2 weeks after injury). FTS inhibited VSMC and splenocyte proliferation as well as interferon-gamma secretion by splenocytes in a dose-dependent manner. Compared with controls, FTS treatment resulted in a strong decrease in Ras-GTP and active ERK, and it significantly reduced intimal thickening after the injury. Ras expression appeared predominantly at areas of neointima regardless of the treatment group. NFkB and iNOS-positive cell numbers were reduced in sections of FTS treated rats. CONCLUSIONS FTS appears to act as a potent inhibitor of intimal thickening in a model of experimental arterial injury.
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MESH Headings
- Animals
- Carotid Artery Injuries/metabolism
- Carotid Artery Injuries/pathology
- Carotid Artery, Common/drug effects
- Carotid Artery, Common/pathology
- Cell Division/drug effects
- Cell Division/physiology
- Cells, Cultured
- Disease Models, Animal
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/pathology
- Enzyme Activation/drug effects
- Farnesol/analogs & derivatives
- Farnesol/pharmacology
- GTP-Binding Proteins/metabolism
- Immunohistochemistry
- Interferon-gamma/metabolism
- Male
- Mitogen-Activated Protein Kinases/antagonists & inhibitors
- Mitogen-Activated Protein Kinases/metabolism
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/pathology
- Rats
- Rats, Wistar
- Salicylates/pharmacology
- Spleen/cytology
- Tunica Intima/drug effects
- Tunica Intima/growth & development
- Tunica Intima/pathology
- ras Proteins/antagonists & inhibitors
- ras Proteins/metabolism
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Affiliation(s)
- Jacob George
- Department of Cardiology and the Cardiovascular Research Laboratory,Tel Aviv Sourasky Medical Center, Tel Aviv University, Sackler School of Medicine, Israel.
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20
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Shohami E, Yatsiv I, Alexandrovich A, Haklai R, Elad-Sfadia G, Grossman R, Biegon A, Kloog Y. The Ras inhibitor S-trans, trans-farnesylthiosalicylic acid exerts long-lasting neuroprotection in a mouse closed head injury model. J Cereb Blood Flow Metab 2003; 23:728-38. [PMID: 12796721 DOI: 10.1097/01.wcb.0000067704.86573.83] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Traumatic brain injury activates N-methyl-d-aspartate receptors (NMDAR) inducing activation of the Ras protein (a key regulator of cell growth, survival, and death) and its effectors. Thus, trauma-induced increase in active Ras-GTP might contribute to traumatic brain injury pathology. Based on this hypothesis, a new concept of neuroprotection is proposed, examined here by investigating the effect of the Ras inhibitor S-trans, trans-farnesylthiosalicylic acid (FTS) in a mouse model of closed head injury (CHI). Mice subjected to CHI were treated systemically 1 h later with FTS (5 mg/kg) or vehicle. After 1 h, Ras-GTP in the contused hemisphere showed a significant (3.8-fold) increase, which was strongly inhibited by FTS (82% inhibition) or by the NMDA-receptor antagonist MK-801 (53%). Both drugs also decreased active (phosphorylated) extracellular signal-regulated kinase. FTS prevented the CHI-induced reduction in NMDAR binding in cortical, striatal, and hippocampal regions, measured by [3H]-MK-801 autoradiography, and decreased lesion size by 50%. It also reduced CHI-induced neurologic deficits, indicated by the highly significant (P < 0.0001) 60% increase in extent of recovery. Thus, FTS provided long-term neuroprotection after CHI, rescuing NMDAR binding in the contused hemisphere and profoundly reducing neurologic deficits. These findings suggest that nontoxic Ras inhibitors such as FTS may qualify as neuroprotective drugs.
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Affiliation(s)
- Esther Shohami
- Department of Pharmacology, School of Pharmacy, Hadassah Medical Center, The Hebrew University, Jerusalem, Israel.
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21
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Elad-Sfadia G, Haklai R, Ballan E, Gabius HJ, Kloog Y. Galectin-1 augments Ras activation and diverts Ras signals to Raf-1 at the expense of phosphoinositide 3-kinase. J Biol Chem 2002; 277:37169-75. [PMID: 12149263 DOI: 10.1074/jbc.m205698200] [Citation(s) in RCA: 176] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Ras proteins activate diverse effector molecules. Depending on the cellular context, Ras activation may have different biological consequences: induction of cell proliferation, senescence, survival, or death. Augmentation and selective activation of particular effector molecules may underlie various Ras actions. In fact, Ras effector-loop mutants interacting with distinctive effectors provide evidence for such selectivity. Interactions of active Ras with escort proteins, such as galectin-1, could also direct Ras selectivity. Here we show that in comparison with Ras transfectants, H-Ras/galectin-1 or K-Ras4B/galectin-1 co-transfectants exhibit enhanced and prolonged epidermal growth factor (EGF)-stimulated increases in Ras-GTP, Raf-1 activity, and active extracellular signal-regulated kinase. Galectin-1 antisense RNA inhibited these EGF responses. Conversely, Ras and galectin-1 co-transfection inhibited the EGF-stimulated increase in phosphoinositide 3-kinase (PI3K) activity. Galectin-1 transfection also inhibited Ras(G12V)-induced PI3K but not Raf-1 activity. Galectin-1 co-immunoprecipitated with Ras(G12V) or with Ras(G12V/T35S) that activate Raf-1 but not with Ras(G12V/Y40C) that activates PI3K. Thus, galectin-1 binds active Ras and diverts its signal to Raf-1 at the expense of PI3K. This demonstrates a novel mechanism controlling the duration and selectivity of the Ras signal. Ras gains selectivity when it is associated with galectin-1, mimicking the selectivity of Ras(T35S), which activates Raf-1 but not PI3K.
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Affiliation(s)
- Galit Elad-Sfadia
- Department of Neurobiochemistry, The George S. Wise Faculty of Life Sciences, Tel-Aviv University, 69978 Tel-Aviv, Israel
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22
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Paz A, Haklai R, Elad-Sfadia G, Ballan E, Kloog Y. Galectin-1 binds oncogenic H-Ras to mediate Ras membrane anchorage and cell transformation. Oncogene 2001; 20:7486-93. [PMID: 11709720 DOI: 10.1038/sj.onc.1204950] [Citation(s) in RCA: 295] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2001] [Revised: 08/28/2001] [Accepted: 09/04/2001] [Indexed: 11/09/2022]
Abstract
Ras genes, frequently mutated in human tumors, promote malignant transformation. Ras transformation requires membrane anchorage, which is promoted by Ras farnesylcysteine carboxymethylester and by a second signal. Previously we showed that the farnesylcysteine mimetic, farnesylthiosalicylic acid (FTS) disrupts Ras membrane anchorage. To understand how this disruption contributes to inhibition of cell transformation we searched for new Ras-interacting proteins and identified galectin-1, a lectin implicated in human tumors, as a selective binding partner of oncogenic H-Ras(12V). The observed size of H-Ras(12V)-galectin-1 complex, which is equal to the sum of the molecular weights of Ras and galectin-1 indicates a direct binding interaction between the two proteins. FTS disrupted H-Ras(12V)-galectin-1 interactions. Overexpression of galectin-1 increased membrane-associated Ras, Ras-GTP, and active ERK resulting in cell transformation, which was blocked by dominant negative Ras. Galectin-1 antisense RNA inhibited transformation by H-Ras(12V) and abolished membrane anchorage of green fluorescent protein (GFP)-H-Ras(12V) but not of GFP-H-Ras wild-type (wt), GFP-K-Ras(12V), or GFP-N-Ras(13V). H-Ras(12V)-galectin-1 interactions establish an essential link between two proteins associated with cell transformation and human malignancies that can be exploited to selectively target oncogenic Ras proteins.
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Affiliation(s)
- A Paz
- Department of Neurobiochemistry, The George S. Wise Faculty of Life Sciences, Tel-Aviv University, 69978 Tel-Aviv, Israel
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