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Gulyás G, Radvánszki G, Matuska R, Balla A, Hunyady L, Balla T, Várnai P. Plasma membrane phosphatidylinositol 4-phosphate and 4,5-bisphosphate determine the distribution and function of K-Ras4B but not H-Ras proteins. J Biol Chem 2017; 292:18862-18877. [PMID: 28939768 DOI: 10.1074/jbc.m117.806679] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 09/11/2017] [Indexed: 11/06/2022] Open
Abstract
Plasma membrane (PM) localization of Ras proteins is crucial for transmitting signals upon mitogen stimulation. Post-translational lipid modification of Ras proteins plays an important role in their recruitment to the PM. Electrostatic interactions between negatively charged PM phospholipids and basic amino acids found in K-Ras4B (K-Ras) but not in H-Ras are important for permanent K-Ras localization to the PM. Here, we investigated how acute depletion of negatively charged PM polyphosphoinositides (PPIns) from the PM alters the intracellular distribution and activity of K- and H-Ras proteins. PPIns depletion from the PM was achieved either by agonist-induced activation of phospholipase C β or with a rapamycin-inducible system in which various phosphatidylinositol phosphatases were recruited to the PM. Redistribution of the two Ras proteins was monitored with confocal microscopy or with a recently developed bioluminescence resonance energy transfer-based approach involving fusion of the Ras C-terminal targeting sequences or the entire Ras proteins to Venus fluorescent protein. We found that PM PPIns depletion caused rapid translocation of K-Ras but not H-Ras from the PM to the Golgi. PM depletion of either phosphatidylinositol 4-phosphate (PtdIns4P) or PtdIns(4,5)P2 but not PtdIns(3,4,5)P3 was sufficient to evoke K-Ras translocation. This effect was diminished by deltarasin, an inhibitor of the Ras-phosphodiesterase interaction, or by simultaneous depletion of the Golgi PtdIns4P. The PPIns depletion decreased incorporation of [3H]leucine in K-Ras-expressing cells, suggesting that Golgi-localized K-Ras is not as signaling-competent as its PM-bound form. We conclude that PPIns in the PM are important regulators of K-Ras-mediated signals.
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Affiliation(s)
- Gergő Gulyás
- From the Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest 1094, Hungary
| | - Glória Radvánszki
- From the Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest 1094, Hungary
| | - Rita Matuska
- From the Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest 1094, Hungary
| | - András Balla
- From the Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest 1094, Hungary.,MTA-SE Laboratory of Molecular Physiology, Hungarian Academy of Sciences and Semmelweis University, Budapest 1094, Hungary, and
| | - László Hunyady
- From the Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest 1094, Hungary.,MTA-SE Laboratory of Molecular Physiology, Hungarian Academy of Sciences and Semmelweis University, Budapest 1094, Hungary, and
| | - Tamas Balla
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, Maryland 20892
| | - Péter Várnai
- From the Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest 1094, Hungary,
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Mustachio LM, Lu Y, Tafe LJ, Memoli V, Rodriguez-Canales J, Mino B, Villalobos PA, Wistuba I, Katayama H, Hanash SM, Roszik J, Kawakami M, Cho KJ, Hancock JF, Chinyengetere F, Hu S, Liu X, Freemantle SJ, Dmitrovsky E. Deubiquitinase USP18 Loss Mislocalizes and Destabilizes KRAS in Lung Cancer. Mol Cancer Res 2017; 15:905-914. [PMID: 28242811 PMCID: PMC5635999 DOI: 10.1158/1541-7786.mcr-16-0369] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 11/22/2016] [Accepted: 02/21/2017] [Indexed: 11/16/2022]
Abstract
KRAS is frequently mutated in lung cancers and is associated with aggressive biology and chemotherapy resistance. Therefore, innovative approaches are needed to treat these lung cancers. Prior work implicated the IFN-stimulated gene 15 (ISG15) deubiquitinase (DUB) USP18 as having antineoplastic activity by regulating lung cancer growth and oncoprotein stability. This study demonstrates that USP18 affects the stability of the KRAS oncoprotein. Interestingly, loss of USP18 reduced KRAS expression, and engineered gain of USP18 expression increased KRAS protein levels in lung cancer cells. Using the protein synthesis inhibitor cycloheximide, USP18 knockdown significantly reduced the half-life of KRAS, but gain of USP18 expression significantly increased its stability. Intriguingly, loss of USP18 altered KRAS subcellular localization by mislocalizing KRAS from the plasma membrane. To explore the biologic consequences, immunohistochemical (IHC) expression profiles of USP18 were compared in lung cancers of KrasLA2/+ versus cyclin E engineered mouse models. USP18 expression was higher in Kras-driven murine lung cancers, indicating a link between KRAS and USP18 expression in vivo To solidify this association, loss of Usp18 in KrasLA2/+ /Usp18-/- mice was found to significantly reduce lung cancers as compared with parental KrasLA2/+ mice. Finally, translational relevance was confirmed in a human lung cancer panel by showing that USP18 IHC expression was significantly higher in KRAS-mutant versus wild-type lung adenocarcinomas.Implications: Taken together, this study highlights a new way to combat the oncogenic consequences of activated KRAS in lung cancer by inhibiting the DUB USP18. Mol Cancer Res; 15(7); 905-14. ©2017 AACR.
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Affiliation(s)
- Lisa Maria Mustachio
- Department of Pharmacology and Toxicology, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
| | - Yun Lu
- Department of Pharmacology and Toxicology, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
| | - Laura J Tafe
- Department of Pathology, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
| | - Vincent Memoli
- Department of Pathology, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
- Norris Cotton Cancer Center, Geisel School of Medicine, Hanover, New Hampshire and Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
| | - Jaime Rodriguez-Canales
- Department of Translational Molecular Pathology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Barbara Mino
- Department of Translational Molecular Pathology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Pamela Andrea Villalobos
- Department of Translational Molecular Pathology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Ignacio Wistuba
- Department of Translational Molecular Pathology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Hiroyuki Katayama
- Department of Clinical Cancer Prevention, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Samir M Hanash
- Department of Clinical Cancer Prevention, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Jason Roszik
- Department of Melanoma Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
- Department of Genomic Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Masanori Kawakami
- Department of Thoracic Head and Neck Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Kwang-Jin Cho
- Department of Integrative Biology and Pharmacology, The University of Texas McGovern Medical School, Houston, Texas
| | - John F Hancock
- Department of Integrative Biology and Pharmacology, The University of Texas McGovern Medical School, Houston, Texas
| | - Fadzai Chinyengetere
- Department of Pharmacology and Toxicology, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
| | - Shanhu Hu
- Department of Pharmacology and Toxicology, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
| | - Xi Liu
- Department of Thoracic Head and Neck Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Sarah J Freemantle
- Department of Pharmacology and Toxicology, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
| | - Ethan Dmitrovsky
- Department of Pharmacology and Toxicology, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire.
- Norris Cotton Cancer Center, Geisel School of Medicine, Hanover, New Hampshire and Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
- Department of Thoracic Head and Neck Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas
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Hou S, Madoux F, Scampavia L, Janovick JA, Conn PM, Spicer TP. Drug Library Screening for the Identification of Ionophores That Correct the Mistrafficking Disorder Associated with Oxalosis Kidney Disease. SLAS DISCOVERY 2017; 22:887-896. [PMID: 28346094 DOI: 10.1177/2472555217689992] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Primary hyperoxaluria is the underlying cause of oxalosis and is a life-threatening autosomal recessive disease, for which treatment may require dialysis or dual liver-kidney transplantation. The most common primary hyperoxaluria type 1 (PH1) is caused by genetic mutations of a liver-specific enzyme alanine:glyoxylate aminotransferase (AGT), which results in the misrouting of AGT from the peroxisomes to the mitochondria. Pharmacoperones are small molecules with the ability to modify misfolded proteins and route them correctly within the cells, which may present an effective strategy to treat AGT misrouting in PH1 disorders. We miniaturized a cell-based high-content assay into 1536-well plate format and screened ~4200 pharmacologically relevant compounds including Food and Drug Administration, European Union, and Japanese-approved drugs. This assay employs CHO cells stably expressing AGT-170, a mutant that predominantly resides in the mitochondria, where we monitor for its relocation to the peroxisomes through automated image acquisition and analysis. The miniaturized 1536-well assay yielded a Z' averaging 0.70 ± 0.07. Three drugs were identified as potential pharmacoperones from this pilot screen, demonstrating the applicability of this assay for large-scale high-throughput screening.
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Affiliation(s)
- Shurong Hou
- 1 Department of Molecular Therapeutics, Scripps Research Institute Molecular Screening Center, Scripps Research Institute, Jupiter, FL, USA
| | - Franck Madoux
- 1 Department of Molecular Therapeutics, Scripps Research Institute Molecular Screening Center, Scripps Research Institute, Jupiter, FL, USA.,3 Amgen Inc., Thousand Oaks, CA
| | - Louis Scampavia
- 1 Department of Molecular Therapeutics, Scripps Research Institute Molecular Screening Center, Scripps Research Institute, Jupiter, FL, USA
| | - Jo Ann Janovick
- 2 Departments of Internal Medicine and Cell Biology/Biochemistry, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - P Michael Conn
- 2 Departments of Internal Medicine and Cell Biology/Biochemistry, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Timothy P Spicer
- 1 Department of Molecular Therapeutics, Scripps Research Institute Molecular Screening Center, Scripps Research Institute, Jupiter, FL, USA
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55
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Ras Proteolipid Nanoassemblies on the Plasma Membrane Sort Lipids With High Selectivity. ACTA ACUST UNITED AC 2017. [DOI: 10.1016/bs.abl.2017.01.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
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56
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Lipid-Sorting Specificity Encoded in K-Ras Membrane Anchor Regulates Signal Output. Cell 2016; 168:239-251.e16. [PMID: 28041850 DOI: 10.1016/j.cell.2016.11.059] [Citation(s) in RCA: 204] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 09/12/2016] [Accepted: 11/29/2016] [Indexed: 11/22/2022]
Abstract
K-Ras is targeted to the plasma membrane by a C-terminal membrane anchor that comprises a farnesyl-cysteine-methyl-ester and a polybasic domain. We used quantitative spatial imaging and atomistic molecular dynamics simulations to examine molecular details of K-Ras plasma membrane binding. We found that the K-Ras anchor binds selected plasma membrane anionic lipids with defined head groups and lipid side chains. The precise amino acid sequence and prenyl group define a combinatorial code for lipid binding that extends beyond simple electrostatics; within this code lysine and arginine residues are non-equivalent and prenyl chain length modifies nascent polybasic domain lipid preferences. The code is realized by distinct dynamic tertiary structures of the anchor on the plasma membrane that govern amino acid side-chain-lipid interactions. An important consequence of this specificity is the ability of such anchors when aggregated to sort subsets of phospholipids into nanoclusters with defined lipid compositions that determine K-Ras signaling output.
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AMPK and Endothelial Nitric Oxide Synthase Signaling Regulates K-Ras Plasma Membrane Interactions via Cyclic GMP-Dependent Protein Kinase 2. Mol Cell Biol 2016; 36:3086-3099. [PMID: 27697864 DOI: 10.1128/mcb.00365-16] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 09/26/2016] [Indexed: 12/22/2022] Open
Abstract
K-Ras must localize to the plasma membrane and be arrayed in nanoclusters for biological activity. We show here that K-Ras is a substrate for cyclic GMP-dependent protein kinases (PKGs). In intact cells, activated PKG2 selectively colocalizes with K-Ras on the plasma membrane and phosphorylates K-Ras at Ser181 in the C-terminal polybasic domain. K-Ras phosphorylation by PKG2 is triggered by activation of AMP-activated protein kinase (AMPK) and requires endothelial nitric oxide synthase and soluble guanylyl cyclase. Phosphorylated K-Ras reorganizes into distinct nanoclusters that retune the signal output. Phosphorylation acutely enhances K-Ras plasma membrane affinity, but phosphorylated K-Ras is progressively lost from the plasma membrane via endocytic recycling. Concordantly, chronic pharmacological activation of AMPK → PKG2 signaling with mitochondrial inhibitors, nitric oxide, or sildenafil inhibits proliferation of K-Ras-positive non-small cell lung cancer cells. The study shows that K-Ras is a target of a metabolic stress-signaling pathway that can be leveraged to inhibit oncogenic K-Ras function.
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58
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Fendiline inhibits proliferation and invasion of pancreatic cancer cells by interfering with ADAM10 activation and β-catenin signaling. Oncotarget 2016; 6:35931-48. [PMID: 26440150 PMCID: PMC4742152 DOI: 10.18632/oncotarget.5933] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 09/14/2015] [Indexed: 12/20/2022] Open
Abstract
ADAM10 (A Disintegrin and Metalloprotease Domain 10) affects the pathophysiology of various cancers, and we had shown that inhibition of ADAM10 sensitizes pancreatic cancer cells to gemcitabine. ADAM10 is activated in response to calcium influx, and here we examined if calcium channel blockers (CCB) would impede ADAM10 activation and affect biology of pancreatic cancer cells. We find that the CCB, fendiline, significantly reduces proliferation, migration, invasion, and anchorage independent growth of pancreatic cancer cells. This was associated with ADAM10 inhibition and its localization at the actin-rich membrane protrusions. Further, fendiline-treated cells formed cadherin-catenin positive tight adherens junctions and elicited defective protein trafficking and recycling. Furthermore, the expression of β-catenin target genes, cyclinD1, c-Myc and CD44, were significantly decreased, suggesting that fendiline might prevent cell proliferation and migration by inhibiting ADAM10 function, cadherin proteolysis and stabilization of cadherin-catenin interaction at the plasma membrane. This will subsequently diminish β-catenin intracellular signaling and repress TCF/LEF target gene expression. Supporting this notion, RNAi-directed downregulation of ADAM10 in cancer cells decreased the expression of cyclinD1, c-Myc and CD44. Furthermore, analysis of human pancreatic tumor tissue microarrays and lysates showed elevated levels of ADAM10, suggesting that aberrant activation of ADAM10 plays a fundamental role in growth and metastasis of PDACs and inhibiting this pathway might be a viable strategy to combat PDACs.
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59
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Salim AA, Tan L, Huang XC, Cho KJ, Lacey E, Hancock JF, Capon RJ. Oligomycins as inhibitors of K-Ras plasma membrane localisation. Org Biomol Chem 2016; 14:711-715. [PMID: 26565618 DOI: 10.1039/c5ob02020d] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Frequently present in pancreatic, colorectal and non-small cell lung carcinomas, oncogenic mutant K-Ras must be localised to the plasma membrane (PM) to be functional. Inhibitors of K-Ras PM localisation are therefore putative cancer chemotherapeutics. By screening a microbial extract library in a high content cell-based assay we detected the rare oligomycin class of Streptomyces polyketides as inhibitors of K-Ras PM localisation. Cultivation and fractionation of three unique oligomycin producing Streptomyces strains yielded oligomycins A-E (1-5) and 21-hydroxy-oligomycin A (6), together with the new 21-hydroxy-oligomycin C (7) and 40-hydroxy-oligomycin B (8). Structures for 1-8 were assigned by detailed spectroscopic analysis. Cancer cell viability screening confirmed 1-8 were cytotoxic to human colorectal carcinoma cells (IC50 > 3 μM), and were inhibitors of the ABC transporter efflux pump P-glycoprotein (P-gp), with 5 being comparable in potency to the positive control verapamil. Significantly, oligomycins 1-8 proved to be exceptionally potent inhibitors of K-Ras PM localisation (Emax 0.67-0.75 with an IC50 ~ 1.5-14 nM).
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Affiliation(s)
- A A Salim
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD 4072, Australia.
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60
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Samantaray S, Correia JN, Garelnabi M, Voelz K, May RC, Hall RA. Novel cell-based in vitro screen to identify small-molecule inhibitors against intracellular replication of Cryptococcus neoformans in macrophages. Int J Antimicrob Agents 2016; 48:69-77. [PMID: 27289450 PMCID: PMC4942879 DOI: 10.1016/j.ijantimicag.2016.04.018] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 04/07/2016] [Accepted: 04/16/2016] [Indexed: 01/08/2023]
Abstract
The fungal pathogen Cryptococcus neoformans poses a major threat to immunocompromised patients and is a leading killer of human immunodeficiency virus (HIV)-infected patients worldwide. Cryptococci are known to manipulate host macrophages and can either remain latent or proliferate intracellularly within the host phagocyte, a favourable niche that also renders them relatively insensitive to antifungal agents. Here we report an attempt to address this limitation by using a fluorescence-based drug screening method to identify potential inhibitors of intracellular proliferation of C. neoformans. The Prestwick Chemical Library(®) of FDA-approved small molecules was screened for compounds that limit the intracellular replication of a fluorescently-tagged C. neoformans reference strain (H99-GFP) in macrophages. Preliminary screening revealed 19 of 1200 compounds that could significantly reduce intracellular growth of the pathogen. Secondary screening and host cell cytotoxicity assays highlighted fendiline hydrochloride as a potential drug candidate for the development of future anticryptococcal therapies. Live cell imaging demonstrated that this Ca(2+) channel blocker strongly enhanced phagosome maturation in macrophages leading to improved fungal killing and reduced intracellular replication. Whilst the relatively high dose of fendiline hydrochloride required renders it unfit for clinical deployment against cryptococcosis, this study highlights a novel approach for identifying new lead compounds and unravels a pharmacologically promising scaffold towards the development of novel antifungal therapies for this neglected disease.
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Affiliation(s)
- Sweta Samantaray
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, UK
| | - Joao N Correia
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, UK
| | - Mariam Garelnabi
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, UK
| | - Kerstin Voelz
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, UK
| | - Robin C May
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, UK.
| | - Rebecca A Hall
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, UK.
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Zhao C, Xiao H, Wu X, Li C, Liang G, Yang S, Lin J. Rational combination of MEK inhibitor and the STAT3 pathway modulator for the therapy in K-Ras mutated pancreatic and colon cancer cells. Oncotarget 2016; 6:14472-87. [PMID: 25961376 PMCID: PMC4546480 DOI: 10.18632/oncotarget.3991] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 04/08/2015] [Indexed: 12/15/2022] Open
Abstract
K-Ras mutations are frequently detected in pancreatic and colon cancers, which are associated with the resistance to MEK inhibitors targeting the Ras pathway. Identifying the underlying mechanisms for the acquired resistance is essential for the future clinical development of MEK inhibitors. Here, we identified that Signal Transducer and Activator of Transcription 3 (STAT3) was significantly activated following the MEK inhibition using AZD6244, PD98059 and Trametinib in K-Ras mutant pancreatic and colon cancer cells. The STAT3 activation may be important for the MEK inhibitor resistance in these K-Ras mutant cancer cells. We have shown that dual inhibition of STAT3 and MEK using the STAT3 inhibitor LY5 and MEK inhibitor Trametinib exerts significant anti-tumor cell efficacy in K-Ras mutant pancreatic and colon cancer cells in vitro. In addition, Trametinib showed increased suppression on tumor growth in vivo in STAT3 knockdown pancreatic cancer cells compared with tumor growth of control cells without STAT3 knockdown. Taken together, our results suggest the induced STAT3 activation as a possible mechanism for the resistance to MEK inhibitor and demonstrate the potentials of a combination therapy using MEK and STAT3 inhibitors in pancreatic and colon cancers harboring K-Ras mutant proteins.
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Affiliation(s)
- Chengguang Zhao
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu, People's Republic of China.,Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Children's Hospital, Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, OH, USA.,Chemical Biology Research Center, School of Pharmaceutical Sciences, Wenzhou Medical University, University Town, Wenzhou, Zhejiang, People's Republic of China
| | - Hui Xiao
- Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Children's Hospital, Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Xiaojuan Wu
- Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Children's Hospital, Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Chenglong Li
- Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, OH, USA
| | - Guang Liang
- Chemical Biology Research Center, School of Pharmaceutical Sciences, Wenzhou Medical University, University Town, Wenzhou, Zhejiang, People's Republic of China
| | - Shulin Yang
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu, People's Republic of China
| | - Jiayuh Lin
- Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Children's Hospital, Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, OH, USA
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Cox AD, Der CJ, Philips MR. Targeting RAS Membrane Association: Back to the Future for Anti-RAS Drug Discovery? Clin Cancer Res 2016; 21:1819-27. [PMID: 25878363 DOI: 10.1158/1078-0432.ccr-14-3214] [Citation(s) in RCA: 280] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
RAS proteins require membrane association for their biologic activity, making this association a logical target for anti-RAS therapeutics. Lipid modification of RAS proteins by a farnesyl isoprenoid is an obligate step in that association, and is an enzymatic process. Accordingly, farnesyltransferase inhibitors (FTI) were developed as potential anti-RAS drugs. The lack of efficacy of FTIs as anticancer drugs was widely seen as indicating that blocking RAS membrane association was a flawed approach to cancer treatment. However, a deeper understanding of RAS modification and trafficking has revealed that this was an erroneous conclusion. In the presence of FTIs, KRAS and NRAS, which are the RAS isoforms most frequently mutated in cancer, become substrates for alternative modification, can still associate with membranes, and can still function. Thus, FTIs failed not because blocking RAS membrane association is an ineffective approach, but because FTIs failed to accomplish that task. Recent findings regarding RAS isoform trafficking and the regulation of RAS subcellular localization have rekindled interest in efforts to target these processes. In particular, improved understanding of the palmitoylation/depalmitoylation cycle that regulates RAS interaction with the plasma membrane, endomembranes, and cytosol, and of the potential importance of RAS chaperones, have led to new approaches. Efforts to validate and target other enzymatically regulated posttranslational modifications are also ongoing. In this review, we revisit lessons learned, describe the current state of the art, and highlight challenging but promising directions to achieve the goal of disrupting RAS membrane association and subcellular localization for anti-RAS drug development. Clin Cancer Res; 21(8); 1819-27. ©2015 AACR. See all articles in this CCR Focus section, "Targeting RAS-Driven Cancers."
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Affiliation(s)
- Adrienne D Cox
- University of North Carolina at Chapel Hill, Lineberger Comprehensive Cancer Center, Chapel Hill, North Carolina.
| | - Channing J Der
- University of North Carolina at Chapel Hill, Lineberger Comprehensive Cancer Center, Chapel Hill, North Carolina.
| | - Mark R Philips
- Perlmutter Cancer Institute, New York University School of Medicine, New York, New York.
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63
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Cho KJ, van der Hoeven D, Zhou Y, Maekawa M, Ma X, Chen W, Fairn GD, Hancock JF. Inhibition of Acid Sphingomyelinase Depletes Cellular Phosphatidylserine and Mislocalizes K-Ras from the Plasma Membrane. Mol Cell Biol 2016; 36:363-74. [PMID: 26572827 PMCID: PMC4719297 DOI: 10.1128/mcb.00719-15] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 08/07/2015] [Accepted: 10/28/2015] [Indexed: 11/20/2022] Open
Abstract
K-Ras must localize to the plasma membrane for biological activity; thus, preventing plasma membrane interaction blocks K-Ras signal output. Here we show that inhibition of acid sphingomyelinase (ASM) mislocalizes both the K-Ras isoforms K-Ras4A and K-Ras4B from the plasma membrane to the endomembrane and inhibits their nanoclustering. We found that fendiline, a potent ASM inhibitor, reduces the phosphatidylserine (PtdSer) and cholesterol content of the inner plasma membrane. These lipid changes are causative because supplementation of fendiline-treated cells with exogenous PtdSer rapidly restores K-Ras4A and K-Ras4B plasma membrane binding, nanoclustering, and signal output. Conversely, supplementation with exogenous cholesterol restores K-Ras4A but not K-Ras4B nanoclustering. These experiments reveal different operational pools of PtdSer on the plasma membrane. Inhibition of ASM elevates cellular sphingomyelin and reduces cellular ceramide levels. Concordantly, delivery of recombinant ASM or exogenous ceramide to fendiline-treated cells rapidly relocalizes K-Ras4B and PtdSer to the plasma membrane. K-Ras4B mislocalization is also recapitulated in ASM-deficient Neimann-Pick type A and B fibroblasts. This study identifies sphingomyelin metabolism as an indirect regulator of K-Ras4A and K-Ras4B signaling through the control of PtdSer plasma membrane content. It also demonstrates the critical and selective importance of PtdSer to K-Ras4A and K-Ras4B plasma membrane binding and nanoscale spatial organization.
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Affiliation(s)
- Kwang-Jin Cho
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Medical School, Houston, Texas, USA
| | - Dharini van der Hoeven
- Department of Diagnostic and Biomedical Sciences, University of Texas Health Science Center at Houston, School of Dentistry, Houston, Texas, USA
| | - Yong Zhou
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Medical School, Houston, Texas, USA
| | - Masashi Maekawa
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, Ontario, Canada Departments of Surgery and Biochemistry, University of Toronto, Toronto, Ontario, Canada Department of Biochemistry and Molecular Genetics, Ehime University Graduate School of Medicine, Toon, Ehime, Japan
| | - Xiaoping Ma
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Medical School, Houston, Texas, USA
| | - Wei Chen
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Medical School, Houston, Texas, USA
| | - Gregory D Fairn
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, Ontario, Canada Departments of Surgery and Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - John F Hancock
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Medical School, Houston, Texas, USA
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McCarthy M, Prakash P, Gorfe AA. Computational allosteric ligand binding site identification on Ras proteins. Acta Biochim Biophys Sin (Shanghai) 2016; 48:3-10. [PMID: 26487442 DOI: 10.1093/abbs/gmv100] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 08/16/2015] [Indexed: 12/19/2022] Open
Abstract
A number of computational techniques have been proposed to expedite the process of allosteric ligand binding site identification in inherently flexible and hence challenging drug targets. Some of these techniques have been instrumental in the discovery of allosteric ligand binding sites on Ras proteins, a group of elusive anticancer drug targets. This review provides an overview of these techniques and their application to Ras proteins. A summary of molecular docking and binding site identification is provided first, followed by a more detailed discussion of two specific techniques for binding site identification in ensembles of Ras conformations generated by molecular simulations.
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Affiliation(s)
- Michael McCarthy
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Priyanka Prakash
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Alemayehu A Gorfe
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
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Fang B. RAS signaling and anti-RAS therapy: lessons learned from genetically engineered mouse models, human cancer cells, and patient-related studies. Acta Biochim Biophys Sin (Shanghai) 2016; 48:27-38. [PMID: 26350096 DOI: 10.1093/abbs/gmv090] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 07/09/2015] [Indexed: 12/13/2022] Open
Abstract
Activating mutations of oncogenic RAS genes are frequently detected in human cancers. The studies in genetically engineered mouse models (GEMMs) reveal that Kras-activating mutations predispose mice to early onset tumors in the lung, pancreas, and gastrointestinal tract. Nevertheless, most of these tumors do not have metastatic phenotypes. Metastasis occurs when tumors acquire additional genetic changes in other cancer driver genes. Studies on clinical specimens also demonstrated that KRAS mutations are present in premalignant tissues and that most of KRAS mutant human cancers have co-mutations in other cancer driver genes, including TP53, STK11, CDKN2A, and KMT2C in lung cancer; APC, TP53, and PIK3CA in colon cancer; and TP53, CDKN2A, SMAD4, and MED12 in pancreatic cancer. Extensive efforts have been devoted to develop therapeutic agents that target enzymes involved in RAS posttranslational modifications, that inhibit downstream effectors of RAS signaling pathways, and that kill RAS mutant cancer cells through synthetic lethality. Recent clinical studies have revealed that sorafenib, a pan-RAF and VEGFR inhibitor, has impressive benefits for KRAS mutant lung cancer patients. Combination therapy of MEK inhibitors with either docetaxel, AKT inhibitors, or PI3K inhibitors also led to improved clinical responses in some KRAS mutant cancer patients. This review discusses knowledge gained from GEMMs, human cancer cells, and patient-related studies on RAS-mediated tumorigenesis and anti-RAS therapy. Emerging evidence demonstrates that RAS mutant cancers are heterogeneous because of the presence of different mutant alleles and/or co-mutations in other cancer driver genes. Effective subclassifications of RAS mutant cancers may be necessary to improve patients' outcomes through personalized precision medicine.
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Affiliation(s)
- Bingliang Fang
- Department of Thoracic and Cardiovascular Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
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66
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Hernandez-Valladares M, Prior IA. Comparative proteomic analysis of compartmentalised Ras signalling. Sci Rep 2015; 5:17307. [PMID: 26620772 PMCID: PMC4664896 DOI: 10.1038/srep17307] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 10/28/2015] [Indexed: 12/27/2022] Open
Abstract
Ras proteins are membrane bound signalling hubs that operate from both the cell surface and endomembrane compartments. However, the extent to which intracellular pools of Ras can contribute to cell signalling is debated. To address this, we have performed a global screen of compartmentalised Ras signalling. We find that whilst ER/Golgi- and endosomal-Ras only generate weak outputs, Ras localised to the mitochondria or Golgi significantly and distinctly influence both the abundance and phosphorylation of a wide range of proteins analysed. Our data reveal that ~80% of phosphosites exhibiting large (≥1.5-fold) changes compared to control can be modulated by organellar Ras signalling. The majority of compartmentalised Ras-specific responses are predicted to influence gene expression, RNA splicing and cell proliferation. Our analysis reinforces the concept that compartmentalisation influences Ras signalling and provides detailed insight into the widespread modulation of responses downstream of endomembranous Ras signalling.
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Affiliation(s)
- Maria Hernandez-Valladares
- Physiological Laboratory, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool L69 3BX, United Kingdom
| | - Ian A Prior
- Physiological Laboratory, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool L69 3BX, United Kingdom
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67
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Wehrens M, ten Wolde PR, Mugler A. Positive feedback can lead to dynamic nanometer-scale clustering on cell membranes. J Chem Phys 2015; 141:205102. [PMID: 25429963 DOI: 10.1063/1.4901888] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Clustering of molecules on biological membranes is a widely observed phenomenon. A key example is the clustering of the oncoprotein Ras, which is known to be important for signal transduction in mammalian cells. Yet, the mechanism by which Ras clusters form and are maintained remains unclear. Recently, it has been discovered that activated Ras promotes further Ras activation. Here we show using particle-based simulation that this positive feedback is sufficient to produce persistent clusters of active Ras molecules at the nanometer scale via a dynamic nucleation mechanism. Furthermore, we find that our cluster statistics are consistent with experimental observations of the Ras system. Interestingly, we show that our model does not support a Turing regime of macroscopic reaction-diffusion patterning, and therefore that the clustering we observe is a purely stochastic effect, arising from the coupling of positive feedback with the discrete nature of individual molecules. These results underscore the importance of stochastic and dynamic properties of reaction diffusion systems for biological behavior.
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Affiliation(s)
- Martijn Wehrens
- FOM Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
| | | | - Andrew Mugler
- FOM Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
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68
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Zeniou M, Fève M, Mameri S, Dong J, Salomé C, Chen W, El-Habr EA, Bousson F, Sy M, Obszynski J, Boh A, Villa P, Assad Kahn S, Didier B, Bagnard D, Junier MP, Chneiweiss H, Haiech J, Hibert M, Kilhoffer MC. Chemical Library Screening and Structure-Function Relationship Studies Identify Bisacodyl as a Potent and Selective Cytotoxic Agent Towards Quiescent Human Glioblastoma Tumor Stem-Like Cells. PLoS One 2015; 10:e0134793. [PMID: 26270679 PMCID: PMC4536076 DOI: 10.1371/journal.pone.0134793] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 07/14/2015] [Indexed: 01/11/2023] Open
Abstract
Cancer stem-like cells reside in hypoxic and slightly acidic tumor niches. Such microenvironments favor more aggressive undifferentiated phenotypes and a slow growing "quiescent state" which preserves them from chemotherapeutic agents that essentially target proliferating cells. Our objective was to identify compounds active on glioblastoma stem-like cells, including under conditions that mimick those found in vivo within this most severe and incurable form of brain malignancy. We screened the Prestwick Library to identify cytotoxic compounds towards glioblastoma stem-like cells, either in a proliferating state or in more slow-growing "quiescent" phenotype resulting from non-renewal of the culture medium in vitro. Compound effects were assessed by ATP-level determination using a cell-based assay. Twenty active molecules belonging to different pharmacological classes have thus been identified. Among those, the stimulant laxative drug bisacodyl was the sole to inhibit in a potent and specific manner the survival of quiescent glioblastoma stem-like cells. Subsequent structure-function relationship studies led to identification of 4,4'-dihydroxydiphenyl-2-pyridyl-methane (DDPM), the deacetylated form of bisacodyl, as the pharmacophore. To our knowledge, bisacodyl is currently the only known compound targeting glioblastoma cancer stem-like cells in their quiescent, more resistant state. Due to its known non-toxicity in humans, bisacodyl appears as a new potential anti-tumor agent that may, in association with classical chemotherapeutic compounds, participate in tumor eradication.
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Affiliation(s)
- Maria Zeniou
- Laboratoire d’Innovation Thérapeutique, Université de Strasbourg / CNRS UMR7200, Laboratoire d’Excellence Medalis, Faculté de Pharmacie, 74 route du Rhin, 67401 Illkirch, France
- * E-mail:
| | - Marie Fève
- Laboratoire d’Innovation Thérapeutique, Université de Strasbourg / CNRS UMR7200, Laboratoire d’Excellence Medalis, Faculté de Pharmacie, 74 route du Rhin, 67401 Illkirch, France
| | - Samir Mameri
- Laboratoire d’Innovation Thérapeutique, Université de Strasbourg / CNRS UMR7200, Laboratoire d’Excellence Medalis, Faculté de Pharmacie, 74 route du Rhin, 67401 Illkirch, France
| | - Jihu Dong
- Laboratoire d’Innovation Thérapeutique, Université de Strasbourg / CNRS UMR7200, Laboratoire d’Excellence Medalis, Faculté de Pharmacie, 74 route du Rhin, 67401 Illkirch, France
| | - Christophe Salomé
- Laboratoire d’Innovation Thérapeutique, Université de Strasbourg / CNRS UMR7200, Laboratoire d’Excellence Medalis, Faculté de Pharmacie, 74 route du Rhin, 67401 Illkirch, France
| | - Wanyin Chen
- Laboratoire d’Innovation Thérapeutique, Université de Strasbourg / CNRS UMR7200, Laboratoire d’Excellence Medalis, Faculté de Pharmacie, 74 route du Rhin, 67401 Illkirch, France
| | - Elias A. El-Habr
- Neuroscience Paris Seine-IBPS, CNRS UMR 8246/ Inserm U1130/ UPMC UMCR18, 7 quai Saint Bernard, 75005 Paris, France
| | - Fanny Bousson
- Laboratoire d’Innovation Thérapeutique, Université de Strasbourg / CNRS UMR7200, Laboratoire d’Excellence Medalis, Faculté de Pharmacie, 74 route du Rhin, 67401 Illkirch, France
| | - Mohamadou Sy
- Laboratoire d’Innovation Thérapeutique, Université de Strasbourg / CNRS UMR7200, Laboratoire d’Excellence Medalis, Faculté de Pharmacie, 74 route du Rhin, 67401 Illkirch, France
| | - Julie Obszynski
- Laboratoire d’Innovation Thérapeutique, Université de Strasbourg / CNRS UMR7200, Laboratoire d’Excellence Medalis, Faculté de Pharmacie, 74 route du Rhin, 67401 Illkirch, France
| | - Alexandre Boh
- Laboratoire d’Innovation Thérapeutique, Université de Strasbourg / CNRS UMR7200, Laboratoire d’Excellence Medalis, Faculté de Pharmacie, 74 route du Rhin, 67401 Illkirch, France
| | - Pascal Villa
- Plateforme de Chimie Biologie Intégrative (PCBIS), Université de Strasbourg / CNRS UMS 3286, Laboratoire d’Excellence Medalis, ESBS Pôle API-Bld Sébastien Brant, 67401 Illkirch, France
| | - Suzana Assad Kahn
- Neuroscience Paris Seine-IBPS, CNRS UMR 8246/ Inserm U1130/ UPMC UMCR18, 7 quai Saint Bernard, 75005 Paris, France
| | - Bruno Didier
- Laboratoire d’Innovation Thérapeutique, Université de Strasbourg / CNRS UMR7200, Laboratoire d’Excellence Medalis, Faculté de Pharmacie, 74 route du Rhin, 67401 Illkirch, France
- Plateforme de Chimie Biologie Intégrative (PCBIS), Université de Strasbourg / CNRS UMS 3286, Laboratoire d’Excellence Medalis, ESBS Pôle API-Bld Sébastien Brant, 67401 Illkirch, France
| | - Dominique Bagnard
- U682, Inserm, Université de Strasbourg, 3, Avenue Molière, 67200 Strasbourg, France
| | - Marie-Pierre Junier
- Neuroscience Paris Seine-IBPS, CNRS UMR 8246/ Inserm U1130/ UPMC UMCR18, 7 quai Saint Bernard, 75005 Paris, France
| | - Hervé Chneiweiss
- Neuroscience Paris Seine-IBPS, CNRS UMR 8246/ Inserm U1130/ UPMC UMCR18, 7 quai Saint Bernard, 75005 Paris, France
| | - Jacques Haiech
- Laboratoire d’Innovation Thérapeutique, Université de Strasbourg / CNRS UMR7200, Laboratoire d’Excellence Medalis, Faculté de Pharmacie, 74 route du Rhin, 67401 Illkirch, France
| | - Marcel Hibert
- Laboratoire d’Innovation Thérapeutique, Université de Strasbourg / CNRS UMR7200, Laboratoire d’Excellence Medalis, Faculté de Pharmacie, 74 route du Rhin, 67401 Illkirch, France
| | - Marie-Claude Kilhoffer
- Laboratoire d’Innovation Thérapeutique, Université de Strasbourg / CNRS UMR7200, Laboratoire d’Excellence Medalis, Faculté de Pharmacie, 74 route du Rhin, 67401 Illkirch, France
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69
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The Role of nAChR and Calcium Signaling in Pancreatic Cancer Initiation and Progression. Cancers (Basel) 2015; 7:1447-71. [PMID: 26264026 PMCID: PMC4586778 DOI: 10.3390/cancers7030845] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 07/14/2015] [Accepted: 07/15/2015] [Indexed: 02/07/2023] Open
Abstract
Pancreatic cancer shows a strong correlation with smoking and the current therapeutic strategies have been relatively ineffective in improving the survival of patients. Efforts have been made over the past many years to understand the molecular events that drive the initiation and progression of pancreatic cancer, especially in the context of smoking. It has become clear that components of tobacco smoke not only initiate these cancers, especially pancreatic ductal adenocarcinomas (PDACs) through their mutagenic properties, but can also promote the growth and metastasis of these tumors by stimulating cell proliferation, angiogenesis, invasion and epithelial-mesenchymal transition. Studies in cell culture systems, animal models and human samples have shown that nicotinic acetylcholine receptor (nAChR) activation enhances these tumor-promoting events by channeling signaling through multiple pathways. In this context, signaling through calcium channels appear to facilitate pancreatic cancer growth by itself or downstream of nAChRs. This review article highlights the role of nAChR downstream signaling events and calcium signaling in the growth, metastasis as well as drug resistance of pancreatic cancer.
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70
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Chien W, Sun QY, Lee KL, Ding LW, Wuensche P, Torres-Fernandez LA, Tan SZ, Tokatly I, Zaiden N, Poellinger L, Mori S, Yang H, Tyner JW, Koeffler HP. Activation of protein phosphatase 2A tumor suppressor as potential treatment of pancreatic cancer. Mol Oncol 2015; 9:889-905. [PMID: 25637283 PMCID: PMC4387089 DOI: 10.1016/j.molonc.2015.01.002] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Revised: 01/07/2015] [Accepted: 01/07/2015] [Indexed: 12/28/2022] Open
Abstract
We utilized three tiers of screening to identify novel therapeutic agents for pancreatic cancers. First, we analyzed 14 pancreatic cancer cell lines against a panel of 66 small-molecule kinase inhibitors and dasatinib was the most potent. Second, we performed RNA expression analysis on 3 dasatinib-resistant and 3 dasatinib-sensitive pancreatic cancer cell lines to profile their gene expression. Third, gene profiling data was integrated with the Connectivity Map database to search for potential drugs. Thioridazine was one of the top ranking small molecules with highly negative enrichment. Thioridazine and its family members of phenothiazine including penfluridol caused pancreatic cancer cell death and affected protein expression levels of molecules involved in cell cycle regulation, apoptosis, and multiple kinase activities. This family of drugs causes activation of protein phosphatase 2 (PP2A). The drug FTY-720 (activator of PP2A) induced apoptosis of pancreatic cancer cells. Silencing catalytic unit of PP2A rendered pancreatic cancer cells resistant to penfluridol. Our observations suggest potential therapeutic use of penfluridol or similar agent associated with activation of PP2A in pancreatic cancers.
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Affiliation(s)
- Wenwen Chien
- Cancer Science Institute of Singapore, National University of Singapore, Singapore.
| | - Qiao-Yang Sun
- Cancer Science Institute of Singapore, National University of Singapore, Singapore
| | - Kian Leong Lee
- Cancer Science Institute of Singapore, National University of Singapore, Singapore
| | - Ling-Wen Ding
- Cancer Science Institute of Singapore, National University of Singapore, Singapore
| | - Peer Wuensche
- Cancer Science Institute of Singapore, National University of Singapore, Singapore
| | | | - Siew Zhuan Tan
- Cancer Science Institute of Singapore, National University of Singapore, Singapore
| | - Itay Tokatly
- Cancer Research Center, Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Tel Hashomer 52621, Israel
| | - Norazean Zaiden
- Cancer Science Institute of Singapore, National University of Singapore, Singapore
| | - Lorenz Poellinger
- Cancer Science Institute of Singapore, National University of Singapore, Singapore
| | - Seiichi Mori
- Cancer Science Institute of Singapore, National University of Singapore, Singapore
| | - Henry Yang
- Cancer Science Institute of Singapore, National University of Singapore, Singapore
| | - Jeffrey W Tyner
- Department of Cell & Developmental Biology, Oregon Health & Science University, Portland, OR 97239, USA
| | - H Phillip Koeffler
- Cancer Science Institute of Singapore, National University of Singapore, Singapore; Cedars-Sinai Medical Center, UCLA School of Medicine, Los Angeles, CA, USA; National University Cancer Institute, Singapore
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71
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Guinney J, Dienstmann R, Ferté C, Friend S, McCormick F. Social interactomes for enabling research communities. Cancer Discov 2014; 4:1265-8. [PMID: 25367949 DOI: 10.1158/2159-8290.cd-14-0774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
SUMMARY Data-driven analyses of scientific abstracts with web apps such as "abstract interactomes" provide a new visualization tool for the biomedical research community to interactively navigate a rich assembly of investigators and identify common research topics. Alternative conference formats such as "social interactomes," with structured, albeit informal, discussions among attendees, are able to engage fellows and top investigators, facilitate the exchange of ideas, and encourage data sharing and future collaborations.
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Affiliation(s)
- Justin Guinney
- Sage Bionetworks, Fred Hutchinson Cancer Research Center, Seattle, Washington.
| | - Rodrigo Dienstmann
- Sage Bionetworks, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Charles Ferté
- Department of Medical Oncology, Institut Gustave Roussy, Villejuif, France. Department of Biostatistics and Epidemiology, Institut Gustave Roussy, Villejuif, France. Department of Innovative Therapeutics and Early Drug Development, Institut Gustave Roussy, Villejuif, France. INSERM U981, University Paris Sud, Institut Gustave Roussy, Villejuif, France
| | - Stephen Friend
- Sage Bionetworks, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Frank McCormick
- Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland. Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, California. Department of Cell and Molecular Pharmacology, University of California, San Francisco, California.
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72
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Zhou Y, Hancock JF. Ras nanoclusters: Versatile lipid-based signaling platforms. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1853:841-9. [PMID: 25234412 DOI: 10.1016/j.bbamcr.2014.09.008] [Citation(s) in RCA: 175] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 09/05/2014] [Accepted: 09/08/2014] [Indexed: 12/31/2022]
Abstract
Ras proteins assemble into transient nanoclusters on the plasma membrane. Nanoclusters are the sites of Ras effector recruitment and activation and are therefore essential for signal transmission. The dynamics of nanocluster formation and disassembly result in interesting emergent properties including high-fidelity signal transmission. More recently the lipid structure of Ras nanoclusters has been reported and shown to contribute to isoform-specific Ras signaling. In addition specific lipids play critical roles in mediating the formation, stability and dynamics of Ras nanoclusters. In consequence the spatiotemporal organization of these lipids has emerged as important and novel regulators of Ras function. This article is part of a Special Issue entitled: Nanoscale membrane organisation and signalling.
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Affiliation(s)
- Yong Zhou
- Department of Integrative Biology and Pharmacology, University of Texas Medical School, Houston, TX 77030, USA.
| | - John F Hancock
- Department of Integrative Biology and Pharmacology, University of Texas Medical School, Houston, TX 77030, USA.
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van Hattum H, Waldmann H. Chemical Biology Tools for Regulating RAS Signaling Complexity in Space and Time. ACTA ACUST UNITED AC 2014; 21:1185-95. [DOI: 10.1016/j.chembiol.2014.08.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Revised: 07/14/2014] [Accepted: 08/01/2014] [Indexed: 12/31/2022]
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A high-throughput assay for small molecule destabilizers of the KRAS oncoprotein. PLoS One 2014; 9:e103836. [PMID: 25093678 PMCID: PMC4122376 DOI: 10.1371/journal.pone.0103836] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Accepted: 07/02/2014] [Indexed: 12/30/2022] Open
Abstract
Mutations in the Ras family of small GTPases, particularly KRAS, occur at high frequencies in cancer and represent a major unmet therapeutic need due to the lack of effective targeted therapies. Past efforts directed at inhibiting the activity of the Ras oncoprotein have proved difficult. We propose an alternative approach to target Ras by eliminating Ras protein from cells with pharmacological means. In this study, we developed a cell-based, high-content screening platform to identify small molecules that could promote the degradation of the KRAS oncoprotein. We generated an EGFP-KRASG12V fluorescence reporter system and implemented it for automated screening in 1536-well plates using high-throughput cellular imaging. We screened a library of clinically relevant compounds at wide dose range and identified Ponatinib and AMG-47a as two candidate compounds that selectively reduced the levels of EGFP-KRASG12V protein but did not affect EGFP protein in cells. This proof-of-principle study demonstrates that it is feasible to use a high-throughput screen to identify compounds that promote the degradation of the Ras oncoprotein as a new approach to target Ras.
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75
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Zimmermann G, Schultz-Fademrecht C, Küchler P, Murarka S, Ismail S, Triola G, Nussbaumer P, Wittinghofer A, Waldmann H. Structure guided design and kinetic analysis of highly potent benzimidazole inhibitors targeting the PDEδ prenyl binding site. J Med Chem 2014; 57:5435-48. [PMID: 24884780 DOI: 10.1021/jm500632s] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
K-Ras is one of the most frequently mutated signal transducing human oncogenes. Ras signaling activity requires correct cellular localization of the GTPase. The spatial organization of K-Ras is controlled by the prenyl binding protein PDEδ, which enhances Ras diffusion in the cytosol. Inhibition of the Ras-PDEδ interaction by small molecules impairs Ras localization and signaling. Here we describe in detail the identification and structure guided development of Ras-PDEδ inhibitors targeting the farnesyl binding pocket of PDEδ with nanomolar affinity. We report kinetic data that characterize the binding of the most potent small molecule ligands to PDEδ and prove their binding to endogenous PDEδ in cell lysates. The PDEδ inhibitors provide promising starting points for the establishment of new drug discovery programs aimed at cancers harboring oncogenic K-Ras.
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Affiliation(s)
- Gunther Zimmermann
- Max Planck Institute of Molecular Physiology , Otto-Hahn-Strasse 11, 44227 Dortmund, Germany
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76
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Ariotti N, Fernández-Rojo MA, Zhou Y, Hill MM, Rodkey TL, Inder KL, Tanner LB, Wenk MR, Hancock JF, Parton RG. Caveolae regulate the nanoscale organization of the plasma membrane to remotely control Ras signaling. ACTA ACUST UNITED AC 2014; 204:777-92. [PMID: 24567358 PMCID: PMC3941050 DOI: 10.1083/jcb.201307055] [Citation(s) in RCA: 103] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Caveolae transduce mechanical stress into plasma membrane lipid alterations that disrupt Ras organization in an isoform-specific manner and modulate downstream signal transduction. The molecular mechanisms whereby caveolae exert control over cellular signaling have to date remained elusive. We have therefore explored the role caveolae play in modulating Ras signaling. Lipidomic and gene array analyses revealed that caveolin-1 (CAV1) deficiency results in altered cellular lipid composition, and plasma membrane (PM) phosphatidylserine distribution. These changes correlated with increased K-Ras expression and extensive isoform-specific perturbation of Ras spatial organization: in CAV1-deficient cells K-RasG12V nanoclustering and MAPK activation were enhanced, whereas GTP-dependent lateral segregation of H-Ras was abolished resulting in compromised signal output from H-RasG12V nanoclusters. These changes in Ras nanoclustering were phenocopied by the down-regulation of Cavin1, another crucial caveolar structural component, and by acute loss of caveolae in response to increased osmotic pressure. Thus, we postulate that caveolae remotely regulate Ras nanoclustering and signal transduction by controlling PM organization. Similarly, caveolae transduce mechanical stress into PM lipid alterations that, in turn, modulate Ras PM organization.
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Affiliation(s)
- Nicholas Ariotti
- The University of Queensland, Institute for Molecular Bioscience, Queensland 4072, Australia
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77
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Ye N, Zhou J. KRAS - An Evolving Cancer Target. AUSTIN JOURNAL OF CANCER AND CLINICAL RESEARCH 2014; 1:1004. [PMID: 27642639 PMCID: PMC5026231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Affiliation(s)
| | - Jia Zhou
- Corresponding author: Jia Zhou, Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX 77555, USA.
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78
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Signal integration by lipid-mediated spatial cross talk between Ras nanoclusters. Mol Cell Biol 2013; 34:862-76. [PMID: 24366544 DOI: 10.1128/mcb.01227-13] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Lipid-anchored Ras GTPases form transient, spatially segregated nanoclusters on the plasma membrane that are essential for high-fidelity signal transmission. The lipid composition of Ras nanoclusters, however, has not previously been investigated. High-resolution spatial mapping shows that different Ras nanoclusters have distinct lipid compositions, indicating that Ras proteins engage in isoform-selective lipid sorting and accounting for different signal outputs from different Ras isoforms. Phosphatidylserine is a common constituent of all Ras nanoclusters but is only an obligate structural component of K-Ras nanoclusters. Segregation of K-Ras and H-Ras into spatially and compositionally distinct lipid assemblies is exquisitely sensitive to plasma membrane phosphatidylserine levels. Phosphatidylserine spatial organization is also modified by Ras nanocluster formation. In consequence, Ras nanoclusters engage in remote lipid-mediated communication, whereby activated H-Ras disrupts the assembly and operation of spatially segregated K-Ras nanoclusters. Computational modeling and experimentation reveal that complex effects of caveolin and cortical actin on Ras nanoclustering are similarly mediated through regulation of phosphatidylserine spatiotemporal dynamics. We conclude that phosphatidylserine maintains the lateral segregation of diverse lipid-based assemblies on the plasma membrane and that lateral connectivity between spatially remote lipid assemblies offers important previously unexplored opportunities for signal integration and signal processing.
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Iglesias DA, Yates MS, van der Hoeven D, Rodkey TL, Zhang Q, Co NN, Burzawa J, Chigurupati S, Celestino J, Bowser J, Broaddus R, Hancock JF, Schmandt R, Lu KH. Another surprise from Metformin: novel mechanism of action via K-Ras influences endometrial cancer response to therapy. Mol Cancer Ther 2013; 12:2847-56. [PMID: 24077915 DOI: 10.1158/1535-7163.mct-13-0439] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Metformin is an oral biguanide commonly used for the treatment of type II diabetes and has recently been demonstrated to possess antiproliferative properties that can be exploited for the prevention and treatment of a variety of cancers. The mechanisms underlying this effect have not been fully elucidated. Using both in vitro and in vivo models, we examined the effects of metformin on endometrial tumors with defined aberrations in the PI3K/PTEN/mTOR and MAPK signaling pathways to understand metformin mechanism of action and identify clinically useful predictors of response to this agent. In vitro assays of proliferation, cytotoxicity, and apoptosis were used to quantify the effects of metformin on endometrial cancer cell lines with mutations in the PI3K/PTEN/mTOR and MAPK signaling pathways. The in vivo effects of oral metformin on tumor progression were further examined using xenograft mouse models of endometrial cancer. K-Ras localization was analyzed by confocal microscopy using GFP-labeled oncogenic K-Ras and by immunoblot following subcellular fractionation. Metformin inhibited cell proliferation, induced apoptosis, and decreased tumor growth in preclinical endometrial cancer models, with the greatest response observed in cells harboring activating mutations in K-Ras. Furthermore, metformin displaces constitutively active K-Ras from the cell membrane, causing uncoupling of the MAPK signaling pathway. These studies provide a rationale for clinical trials using metformin in combination with PI3K-targeted agents for tumors harboring activating K-Ras mutations, and reveal a novel mechanism of action for metformin.
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Affiliation(s)
- David A Iglesias
- Corresponding Author: Karen H. Lu, Department of Gynecologic Oncology and Reproductive Medicine, 1155 Hermann Pressler Dr., Unit 1362, Houston, TX 77030.
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80
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Abstract
Oncogenic mutant K-Ras is highly prevalent in multiple human tumors. Despite significant efforts to directly target Ras activity, no K-Ras-specific inhibitors have been developed and taken into the clinic. Since Ras proteins must be anchored to the inner leaflet of the plasma membrane (PM) for full biological activity, we devised a high-content screen to identify molecules with ability to displace K-Ras from the PM. Here we summarize the biochemistry and biology of three classes of compound identified by this screening method that inhibit K-Ras PM targeting: staurosporine and analogs, fendiline, and metformin. All three classes of compound significantly abrogate cell proliferation and Ras signaling in K-Ras-transformed cancer cells. Taken together, these studies provide an important proof of concept that blocking PM localization of K-Ras is a tractable therapeutic target.
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Affiliation(s)
- Kwang-Jin Cho
- Department of Integrative Biology and Pharmacology, The University of Texas Medical School at Houston, Houston, Texas, USA
| | - Dharini van der Hoeven
- Department of Diagnostic and Biomedical Sciences, The University of Texas School of Dentistry at Houston, Houston, Texas, USA
| | - John F Hancock
- Department of Integrative Biology and Pharmacology, The University of Texas Medical School at Houston, Houston, Texas, USA.
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81
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Prakash P, Gorfe AA. Lessons from computer simulations of Ras proteins in solution and in membrane. Biochim Biophys Acta Gen Subj 2013; 1830:5211-8. [PMID: 23906604 DOI: 10.1016/j.bbagen.2013.07.024] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 07/23/2013] [Accepted: 07/24/2013] [Indexed: 12/22/2022]
Abstract
BACKGROUND A great deal has been learned over the last several decades about the function of Ras proteins in solution and membrane environments. While much of this knowledge has been derived from a plethora of experimental techniques, computer simulations have also played a substantial role. SCOPE OF REVIEW Our goal here is to summarize the contribution of molecular simulations to our current understanding of normal and aberrant Ras function. We focus on lessons from molecular dynamics simulations in aqueous and membrane environments. MAJOR CONCLUSIONS The central message is that a close interaction between theory and simulation on the one hand and cell-biological, spectroscopic and other experimental approaches on the other has played, and will likely continue to play, a vital role in Ras research. GENERAL SIGNIFICANCE Atomistic insights emerging from detailed simulations of Ras in solution and in bilayers may be the key to unlock the secret that to date prevented development of selective anti-Ras inhibitors for cancer therapy.
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Affiliation(s)
- Priyanka Prakash
- University of Texas Health Science Center at Houston, Department of Integrative Biology and Pharmacology, 6431 Fannin St., Houston, TX 77030, USA
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82
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Wang Y, Kaiser CE, Frett B, Li HY. Targeting mutant KRAS for anticancer therapeutics: a review of novel small molecule modulators. J Med Chem 2013; 56:5219-30. [PMID: 23566315 PMCID: PMC4666308 DOI: 10.1021/jm3017706] [Citation(s) in RCA: 93] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The RAS proteins play a role in cell differentiation, proliferation, and survival. Aberrant RAS signaling has been found to play a role in 30% of all cancers. KRAS, a key member of the RAS protein family, is an attractive cancer target, as frequent point mutations in the KRAS gene render the protein constitutively active. A number of attempts have been made to target aberrant KRAS signaling by identifying small molecule compounds that (1) are synthetic lethal to mutant KRAS, (2) block KRAS/GEF interactions, (3) inhibit downstream KRAS effectors, or (4) inhibit the post-translational processing of RAS proteins. In addition, inhibition of novel targets outside the main KRAS signaling pathway, specifically the cell cycle related kinase PLK1, has been shown have an effect in cells that harbor mutant KRAS. Herein we review the use of various high-throughput screening assays utilized to identify new small-molecule compounds capable of targeting mutant KRAS-driven cancers.
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Affiliation(s)
- Yuanxiang Wang
- Department of Pharmacoloy and Toxicology, College of Pharmacy, The University of Arizona, Tucson, Arizona 85721, United States
- BIO5 Oro Valley, The University of Arizona, 1580 Hanley Boulevard, Oro Valley, Arizona 85737, United States
| | - Christine E. Kaiser
- Department of Pharmacoloy and Toxicology, College of Pharmacy, The University of Arizona, Tucson, Arizona 85721, United States
| | - Brendan Frett
- Department of Pharmacoloy and Toxicology, College of Pharmacy, The University of Arizona, Tucson, Arizona 85721, United States
- BIO5 Oro Valley, The University of Arizona, 1580 Hanley Boulevard, Oro Valley, Arizona 85737, United States
| | - Hong-yu Li
- Department of Pharmacoloy and Toxicology, College of Pharmacy, The University of Arizona, Tucson, Arizona 85721, United States
- BIO5 Oro Valley, The University of Arizona, 1580 Hanley Boulevard, Oro Valley, Arizona 85737, United States
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83
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Andrographolide derivatives inhibit guanine nucleotide exchange and abrogate oncogenic Ras function. Proc Natl Acad Sci U S A 2013; 110:10201-6. [PMID: 23737504 DOI: 10.1073/pnas.1300016110] [Citation(s) in RCA: 117] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Aberrant signaling by oncogenic mutant rat sarcoma (Ras) proteins occurs in ∼15% of all human tumors, yet direct inhibition of Ras by small molecules has remained elusive. Recently, several small-molecule ligands have been discovered that directly bind Ras and inhibit its function by interfering with exchange factor binding. However, it is unclear whether, or how, these ligands could lead to drugs that act against constitutively active oncogenic mutant Ras. Using a dynamics-based pocket identification scheme, ensemble docking, and innovative cell-based assays, here we show that andrographolide (AGP)--a bicyclic diterpenoid lactone isolated from Andrographis paniculata--and its benzylidene derivatives bind to transient pockets on Kirsten-Ras (K-Ras) and inhibit GDP-GTP exchange. As expected for inhibitors of exchange factor binding, AGP derivatives reduced GTP loading of wild-type K-Ras in response to acute EGF stimulation with a concomitant reduction in MAPK activation. Remarkably, however, prolonged treatment with AGP derivatives also reduced GTP loading of, and signal transmission by, oncogenic mutant K-RasG12V. In sum, the combined analysis of our computational and cell biology results show that AGP derivatives directly bind Ras, block GDP-GTP exchange, and inhibit both wild-type and oncogenic K-Ras signaling. Importantly, our findings not only show that nucleotide exchange factors are required for oncogenic Ras signaling but also demonstrate that inhibiting nucleotide exchange is a valid approach to abrogating the function of oncogenic mutant Ras.
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84
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吕 亚. Identification of Lung Cancer Related Function Modules Based on Co-Expression Network. Biophysics (Nagoya-shi) 2013. [DOI: 10.12677/biphy.2013.11003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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85
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Sugar-Based Inhibitors of Ras Activation. ACTA ACUST UNITED AC 2013. [DOI: 10.1016/b978-0-12-416749-0.00005-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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