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Abstract
Hutchinson-Gilford progeria syndrome (HGPS) is a sporadic, autosomal dominant disorder characterized by premature and accelerated aging symptoms leading to death at the mean age of 14.6 years usually due to cardiovascular complications. HGPS is caused by a de novo point mutation in the LMNA gene encoding the intermediate filament proteins lamins A and C which are structural components of the nuclear lamina. This mutation leads to the production of a truncated toxic form of lamin A, issued from aberrant splicing and called progerin. Progerin accumulates in HGPS cells' nuclei and is a hallmark of the disease. Small amounts of progerin are also produced during normal aging. HGPS cells and animal preclinical models have provided insights into the molecular and cellular pathways that underlie the disease and have also highlighted possible mechanisms involved in normal aging. This review reports recent medical advances and treatment approaches for patients affected with HGPS.
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Affiliation(s)
- Karim Harhouri
- a Aix Marseille Univ, INSERM, MMG - U1251 , Marseille , France
| | - Diane Frankel
- a Aix Marseille Univ, INSERM, MMG - U1251 , Marseille , France.,b APHM, Hôpital la Timone, Service de Biologie Cellulaire , Marseille , France
| | | | - Patrice Roll
- a Aix Marseille Univ, INSERM, MMG - U1251 , Marseille , France.,b APHM, Hôpital la Timone, Service de Biologie Cellulaire , Marseille , France
| | - Annachiara De Sandre-Giovannoli
- a Aix Marseille Univ, INSERM, MMG - U1251 , Marseille , France.,c APHM, Hôpital la Timone , Département de Génétique Médicale , Marseille , France
| | - Nicolas Lévy
- a Aix Marseille Univ, INSERM, MMG - U1251 , Marseille , France.,c APHM, Hôpital la Timone , Département de Génétique Médicale , Marseille , France
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Abstract
Ras oncoproteins play pivotal roles in both the development and maintenance of many tumor types. Unfortunately, these proteins are difficult to directly target using traditional pharmacological strategies, in part due to their lack of obvious binding pockets or allosteric sites. This obstacle has driven a considerable amount of research into pursuing alternative ways to effectively inhibit Ras, examples of which include inducing mislocalization to prevent Ras maturation and inactivating downstream proteins in Ras-driven signaling pathways. Ras proteins are archetypes of a superfamily of small GTPases that play specific roles in the regulation of many cellular processes, including vesicle trafficking, nuclear transport, cytoskeletal rearrangement, and cell cycle progression. Several other superfamily members have also been linked to the control of normal and cancer cell growth and survival. For example, Rap1 has high sequence similarity to Ras, has overlapping binding partners, and has been demonstrated to both oppose and mimic Ras-driven cancer phenotypes. Rap1 plays an important role in cell adhesion and integrin function in a variety of cell types. Mechanistically, Ras and Rap1 cooperate to initiate and sustain ERK signaling, which is activated in many malignancies and is the target of successful therapeutics. Here we review the role activated Rap1 in ERK signaling and other downstream pathways to promote invasion and cell migration and metastasis in various cancer types.
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Affiliation(s)
- Seema Shah
- Program in Cancer Biology, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Ethan J Brock
- Program in Cancer Biology, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Kyungmin Ji
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Raymond R Mattingly
- Program in Cancer Biology, Wayne State University School of Medicine, Detroit, MI 48201, USA; Department of Pharmacology, Wayne State University School of Medicine, Detroit, MI 48201, USA.
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Wu D, Yates PA, Zhang H, Cao K. Comparing lamin proteins post-translational relative stability using a 2A peptide-based system reveals elevated resistance of progerin to cellular degradation. Nucleus 2017; 7:585-596. [PMID: 27929926 PMCID: PMC5214577 DOI: 10.1080/19491034.2016.1260803] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [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] [Indexed: 11/22/2022] Open
Abstract
Nuclear lamins are the major components of the nuclear lamina at the periphery of the nucleus, supporting the nuclear envelope and participating in many nuclear processes, including DNA replication, transcription and chromatin organization. A group of diseases, the laminopathies, is associated with mutations in lamin genes. One of the most striking cases is Hutchinson-Gilford progeria syndrome (HGPS) which is the consequence of a lamin A dominant negative mutant named progerin. Due to the abnormal presence of a permanent C-terminal farnesyl tail, progerin gradually accumulates on the nuclear membrane, perturbing a diversity of signalings and transcriptional events. The accumulation of progerin has led to the speculation that progerin possesses higher stability than the wild type lamin A protein. However, the low solubility of lamin proteins renders traditional immunoprecipitation-dependent methods such as pulse-chase analysis ineffective for comparing the relative stabilities of mutant and wild type lamins. Here, we employ a novel platform for inferring differences in lamin stability, which is based on normalization to a co-translated reporter protein following porcine teschovirus-1 2A peptide-mediated co-translational cleavage. The results obtained using this method support the notion that progerin is more stable than lamin A. Moreover, treatment of FTI reduces progerin relative stability to the level of wild type lamin A.
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Affiliation(s)
- Di Wu
- a Department of Cell Biology and Molecular Genetics , University of Maryland College Park , MD , USA
| | - Phillip A Yates
- b The Department of Biochemistry and Molecular Biology , Oregon Health & Science University , Portland , OR , USA
| | - Haoyue Zhang
- a Department of Cell Biology and Molecular Genetics , University of Maryland College Park , MD , USA
| | - Kan Cao
- a Department of Cell Biology and Molecular Genetics , University of Maryland College Park , MD , USA
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Ojanperä I, Kriikku P, Vuori E. Fatal toxicity index of medicinal drugs based on a comprehensive toxicology database. Int J Legal Med 2016; 130:1209-16. [PMID: 26987318 DOI: 10.1007/s00414-016-1358-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Accepted: 03/07/2016] [Indexed: 10/22/2022]
Abstract
The fatal toxicity index (FTI) is the absolute number of fatal poisonings caused by a particular drug divided by its consumption figure. Consequently, it is a useful measure in evaluating toxicity of the drug and its relevance in fatal poisonings. In this study, we assessed the FTI of medicinal drugs in 3 years (2005, 2009, and 2013) in Finland. As the measure of drug consumption, we used the number of defined daily doses (DDD) per population in each year. There were 70 medicinal drugs in Finland for which the mean FTI expressed as the number of deaths per million DDD over the three study years was higher or equal to 0.1. The Anatomical Therapeutic Chemical (ATC) classification system was used for the classification of the active ingredients of medicinal drugs according to the organ or system which they act on. Of these 70 drugs, 55 drugs (78.6 %) acted on the nervous system (denoted by ATC code N), 11 (15.7 %) on the cardiovascular system (C), three (4.3 %) on the alimentary tract and metabolism (A), and one (1.4 %) on the musculoskeletal system (M). The nervous system drugs consisted of 20 psycholeptics, (ATC code N05), 20 psychoanaleptics (N06), eight analgesics (N02), six antiepileptics (N03), and one other nervous system drug (N07). The highest individual FTIs were associated with the opioids methadone, dextropropoxyphene, oxycodone, tramadol, and morphine; the antipsychotics levomepromazine and chlorprothixene; and the antidepressants doxepin, amitriptyline, trimipramine, and bupropion. Buprenorphine was not included in the study, because most of the fatal buprenorphine poisonings were due to smuggled tablets. A clearly increasing trend in FTI was observed with pregabalin and possibly with bupropion, both drugs emerging as abused substances.
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Affiliation(s)
- Ilkka Ojanperä
- Department of Forensic Medicine, University of Helsinki, PO Box 40, Kytösuontie 11, FI-00014, Helsinki, Finland
| | - Pirkko Kriikku
- Department of Forensic Medicine, University of Helsinki, PO Box 40, Kytösuontie 11, FI-00014, Helsinki, Finland.
| | - Erkki Vuori
- Department of Forensic Medicine, University of Helsinki, PO Box 40, Kytösuontie 11, FI-00014, Helsinki, Finland
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Noda A, Mishima S, Hirai Y, Hamasaki K, Landes RD, Mitani H, Haga K, Kiyono T, Nakamura N, Kodama Y. Progerin, the protein responsible for the Hutchinson-Gilford progeria syndrome, increases the unrepaired DNA damages following exposure to ionizing radiation. Genes Environ 2015; 37:13. [PMID: 27350809 PMCID: PMC4917958 DOI: 10.1186/s41021-015-0018-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [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: 04/06/2015] [Accepted: 07/10/2015] [Indexed: 12/21/2022] Open
Abstract
Introduction Progerin, the protein responsible for the Hutchinson-Gilford Progeria Syndrome (HGPS), is a partially deleted form of nuclear lamin A, and its expression has been suggested as a cause for dysfunctional nuclear membrane and premature senescence. To examine the role of nuclear envelop architecture in regulating cellular aging and DNA repair, we used ionizing radiation to increase the number of DNA double strand breaks (DSBs) in normal and HGPS cells, and analyzed possible relationship between unrepaired DSBs and cellular aging. Results We found that HGPS cells are normal in repairing a major fraction of radiation-induced double strand breaks (M-DSBs)but abnormal to show increased amount of residual unrepaired DSBs (R-DSBs). Such unrepaired DSBs were 2.6 times (CI 95 %: 2.2–3.2) higher than that in normal cells one week after the irradiation, and 1.6 times (CI 95 %: 1.3–1.9) higher even one month after the irradiation. These damages tend to increase as the nuclear envelope become abnormal, a characteristic of both HGPS and normal human cells which undergo replicative senescence. The artificial, enforced over-expression of progerin further impaired the repair of M-DSBs, implying lamin A-associated nuclear membrane has an important role for DNA DSB repair. Introduction of telomerase gene function in HGPS cells reversed such aging phenotypes along with upregulation of lamin B1 and downregulation of progerin, which is a hallmark of young cells. Conclusion We suggest that lamin A- or progerin-associated nuclear envelope is involved in cellular aging associated with DNA damage repair. Electronic supplementary material The online version of this article (doi:10.1186/s41021-015-0018-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Asao Noda
- Department of Genetics, Radiation Effects Research Foundation, 5-2 Hijiyama-Park, Minami-Ku, Hiroshima 732-0815 Japan
| | - Shuji Mishima
- Department of Genetics, Radiation Effects Research Foundation, 5-2 Hijiyama-Park, Minami-Ku, Hiroshima 732-0815 Japan
| | - Yuko Hirai
- Department of Genetics, Radiation Effects Research Foundation, 5-2 Hijiyama-Park, Minami-Ku, Hiroshima 732-0815 Japan
| | - Kanya Hamasaki
- Department of Genetics, Radiation Effects Research Foundation, 5-2 Hijiyama-Park, Minami-Ku, Hiroshima 732-0815 Japan
| | - Reid D Landes
- Department of Statistics, Radiation Effects Research Foundation, 5-2 Hijiyama-Park, Minami-Ku, Hiroshima 732-0815 Japan
| | - Hiroshi Mitani
- Department of Integrated Biosciences, Graduate School of Sciences, The University of Tokyo, Kashiwa-no-ha 5-1-5, Kashiwa, Chiba 277-8572 Japan
| | - Kei Haga
- Division of Virology, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045 Japan
| | - Tohru Kiyono
- Division of Carcinogenesis and Cancer Prevention, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045 Japan
| | - Nori Nakamura
- Department of Genetics, Radiation Effects Research Foundation, 5-2 Hijiyama-Park, Minami-Ku, Hiroshima 732-0815 Japan
| | - Yoshiaki Kodama
- Department of Genetics, Radiation Effects Research Foundation, 5-2 Hijiyama-Park, Minami-Ku, Hiroshima 732-0815 Japan
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Buss SJ, Krautz B, Hofmann N, Sander Y, Rust L, Giusca S, Galuschky C, Seitz S, Giannitsis E, Pleger S, Raake P, Most P, Katus HA, Korosoglou G. Prediction of functional recovery by cardiac magnetic resonance feature tracking imaging in first time ST-elevation myocardial infarction. Comparison to infarct size and transmurality by late gadolinium enhancement. Int J Cardiol 2015; 183:162-70. [PMID: 25675901 DOI: 10.1016/j.ijcard.2015.01.022] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Revised: 12/23/2014] [Accepted: 01/04/2015] [Indexed: 12/18/2022]
Abstract
PURPOSE To investigate whether myocardial deformation imaging, assessed by feature tracking cardiac magnetic resonance (FTI-CMR), would allow objective quantification of myocardial strain and estimation of functional recovery in patients with first time ST-elevation myocardial infarction (STEMI). METHODS Cardiac magnetic resonance (CMR) imaging was performed in 74 consecutive patients 2-4 days after successfully reperfused STEMI, using a 1.5T CMR scanner (Philips Achieva). Peak systolic circumferential and longitudinal strains were measured using the FTI applied to SSFP cine sequences and were compared to infarct size, determined by late gadolinium enhancement (LGE). Follow-up CMR at 6 months was performed in order to assess residual ejection fraction, which deemed as the reference standard for the estimation of functional recovery. RESULTS During the follow-up period 53 of 74 (72%) patients exhibited preserved residual ejection fraction ≥50%. A cut-off value of -19.3% for global circumferential strain identified patients with preserved ejection fraction ≥50% at follow-up with sensitivity of 76% and specificity of 85% (AUC=0.86, 95% CI=0.75-0.93, p<0.001), which was superior to that provided by longitudinal strain (ΔAUC=0.13, SE=0.05, z-statistic=2.5, p=0.01), and non-inferior to that provided by LGE (ΔAUC=0.07, p=NS). Multivariate analysis showed that global circumferential strain and LGE exhibited independent value for the prediction of preserved LV-function, surpassing that provided by age, diabetes and baseline ejection fraction (HR=1.4, 95% CI=1.0-1.9 and HR=1.4, 95% CI=1.1-1.7, respectively, p<0.05 for both). CONCLUSIONS Estimation of circumferential strain by FTI provides objective assessment of infarct size without the need for contrast agent administration and estimation of functional recovery with non-inferior accuracy compared to that provided by LGE.
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Affiliation(s)
- Sebastian J Buss
- Department of Cardiology, University of Heidelberg, INF 410, 69120 Heidelberg, Germany
| | - Birgit Krautz
- Department of Cardiology, University of Heidelberg, INF 410, 69120 Heidelberg, Germany
| | - Nina Hofmann
- Department of Cardiology, University of Heidelberg, INF 410, 69120 Heidelberg, Germany
| | - Yannick Sander
- Department of Cardiology, University of Heidelberg, INF 410, 69120 Heidelberg, Germany
| | - Lukas Rust
- Department of Cardiology, University of Heidelberg, INF 410, 69120 Heidelberg, Germany
| | - Sorin Giusca
- Department of Cardiology, University of Heidelberg, INF 410, 69120 Heidelberg, Germany
| | | | - Sebastian Seitz
- Department of Cardiology, University of Heidelberg, INF 410, 69120 Heidelberg, Germany
| | - Evangelos Giannitsis
- Department of Cardiology, University of Heidelberg, INF 410, 69120 Heidelberg, Germany
| | - Sven Pleger
- Department of Cardiology, University of Heidelberg, INF 410, 69120 Heidelberg, Germany
| | - Philip Raake
- Department of Cardiology, University of Heidelberg, INF 410, 69120 Heidelberg, Germany
| | - Patrick Most
- Department of Cardiology, University of Heidelberg, INF 410, 69120 Heidelberg, Germany
| | - Hugo A Katus
- Department of Cardiology, University of Heidelberg, INF 410, 69120 Heidelberg, Germany
| | - Grigorios Korosoglou
- Department of Cardiology, University of Heidelberg, INF 410, 69120 Heidelberg, Germany.
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Schuld NJ, Vervacke JS, Lorimer EL, Simon NC, Hauser AD, Barbieri JT, Distefano MD, Williams CL. The chaperone protein SmgGDS interacts with small GTPases entering the prenylation pathway by recognizing the last amino acid in the CAAX motif. J Biol Chem 2014; 289:6862-6876. [PMID: 24415755 PMCID: PMC3945348 DOI: 10.1074/jbc.m113.527192] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [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: 10/24/2013] [Revised: 01/09/2014] [Indexed: 12/31/2022] Open
Abstract
Ras family small GTPases localize at the plasma membrane, where they can activate oncogenic signaling pathways. Understanding the mechanisms that promote membrane localization of GTPases will aid development of new therapies to inhibit oncogenic signaling. We previously reported that SmgGDS splice variants promote prenylation and trafficking of GTPases containing a C-terminal polybasic region and demonstrated that SmgGDS-607 interacts with nonprenylated GTPases, whereas SmgGDS-558 interacts with prenylated GTPases in cells. The mechanism that SmgGDS-607 and SmgGDS-558 use to differentiate between prenylated and nonprenylated GTPases has not been characterized. Here, we provide evidence that SmgGDS-607 associates with GTPases through recognition of the last amino acid in the CAAX motif. We show that SmgGDS-607 forms more stable complexes in cells with nonprenylated GTPases that will become geranylgeranylated than with nonprenylated GTPases that will become farnesylated. These binding relationships similarly occur with nonprenylated SAAX mutants. Intriguingly, farnesyltransferase inhibitors increase the binding of WT K-Ras to SmgGDS-607, indicating that the pharmacological shunting of K-Ras into the geranylgeranylation pathway promotes K-Ras association with SmgGDS-607. Using recombinant proteins and prenylated peptides corresponding to the C-terminal sequences of K-Ras and Rap1B, we found that both SmgGDS-607 and SmgGDS-558 directly bind the GTPase C-terminal region, but the specificity of the SmgGDS splice variants for prenylated versus nonprenylated GTPases is diminished in vitro. Finally, we present structural homology models and data from functional prediction software to define both similar and unique features of SmgGDS-607 when compared with SmgGDS-558.
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Affiliation(s)
- Nathan J Schuld
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Jeffrey S Vervacke
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55414
| | - Ellen L Lorimer
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Nathan C Simon
- Department of Microbiology, Immunology, and Molecular Genetics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Andrew D Hauser
- Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Joseph T Barbieri
- Department of Microbiology, Immunology, and Molecular Genetics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Mark D Distefano
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55414
| | - Carol L Williams
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226.
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Mabanglo MF, Hast MA, Lubock NB, Hellinga HW, Beese LS. Crystal structures of the fungal pathogen Aspergillus fumigatus protein farnesyltransferase complexed with substrates and inhibitors reveal features for antifungal drug design. Protein Sci 2014; 23:289-301. [PMID: 24347326 PMCID: PMC3945837 DOI: 10.1002/pro.2411] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [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: 10/14/2013] [Revised: 12/11/2013] [Accepted: 12/11/2013] [Indexed: 11/07/2022]
Abstract
Species of the fungal genus Aspergillus are significant human and agricultural pathogens that are often refractory to existing antifungal treatments. Protein farnesyltransferase (FTase), a critical enzyme in eukaryotes, is an attractive potential target for antifungal drug discovery. We report high-resolution structures of A. fumigatus FTase (AfFTase) in complex with substrates and inhibitors. Comparison of structures with farnesyldiphosphate (FPP) bound in the absence or presence of peptide substrate, corresponding to successive steps in ordered substrate binding, revealed that the second substrate-binding step is accompanied by motions of a loop in the catalytic site. Re-examination of other FTase structures showed that this motion is conserved. The substrate- and product-binding clefts in the AfFTase active site are wider than in human FTase (hFTase). Widening is a consequence of small shifts in the α-helices that comprise the majority of the FTase structure, which in turn arise from sequence variation in the hydrophobic core of the protein. These structural effects are key features that distinguish fungal FTases from hFTase. Their variation results in differences in steady-state enzyme kinetics and inhibitor interactions and presents opportunities for developing selective anti-fungal drugs by exploiting size differences in the active sites. We illustrate the latter by comparing the interaction of ED5 and Tipifarnib with hFTase and AfFTase. In AfFTase, the wider groove enables ED5 to bind in the presence of FPP, whereas in hFTase it binds only in the absence of substrate. Tipifarnib binds similarly to both enzymes but makes less extensive contacts in AfFTase with consequently weaker binding.
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Affiliation(s)
- Mark F Mabanglo
- Department of Biochemistry, Duke University Medical CenterDurham, North Carolina, 27710
| | - Michael A Hast
- Department of Biochemistry, Duke University Medical CenterDurham, North Carolina, 27710
| | - Nathan B Lubock
- Department of Biochemistry, Duke University Medical CenterDurham, North Carolina, 27710
| | - Homme W Hellinga
- Department of Biochemistry, Duke University Medical CenterDurham, North Carolina, 27710
| | - Lorena S Beese
- Department of Biochemistry, Duke University Medical CenterDurham, North Carolina, 27710
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Tamanoi F, Lu J. Recent progress in developing small molecule inhibitors designed to interfere with ras membrane association: toward inhibiting K-Ras and N-Ras functions. Enzymes 2013; 34 Pt. B:181-200. [PMID: 25034105 DOI: 10.1016/b978-0-12-420146-0.00008-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
K-Ras and N-Ras are mutated in a wide range of human cancers, thus making these proteins attractive targets of anticancer drug development. However, no effective compounds have been obtained so far. One of the approaches taken to inhibit the function of K-Ras and N-Ras is to interfere with their membrane association. Various attempts have been taken. In the first example, we examine the approach conceived in early 1990s to inhibit protein prenylation that is required for their membrane association. The initial premise that the inhibition of Ras farnesylation leads to the inhibition of Ras was not realized, mainly due to alternative prenylation of K-Ras and N-Ras proteins. This led to the idea that the combined inhibition of FTase and GGTase-I can block membrane association of K-Ras and N-Ras. Dual specificity inhibitors of FTase and GGTase-I (DPIs) were also developed. These compounds were tested in preclinical and clinical studies. It appears that sufficiently high concentration of the drug to inhibit K-Ras was not achieved in previous attempts. In addition, dose-limiting toxicity has been observed and this was primarily ascribed to GGTase-I inhibition. Strategies to confer cancer targeting capabilities to the inhibitors may overcome the dose-limiting toxicity. In the second approach, postprenylation events were exploited. This led to the development of various inhibitors including the ICMT inhibitors. Finally, recent identification of compounds that inhibit the interaction between K-Ras and PDE-δ is discussed.
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Affiliation(s)
- Fuyuhiko Tamanoi
- Department of Microbiology, Immunology & Molecular Genetics, Jonsson Comprehensive Cancer Center, Molecular Biology Institute, University of California, Los Angeles, California, USA.
| | - Jie Lu
- Department of Microbiology, Immunology & Molecular Genetics, Jonsson Comprehensive Cancer Center, Molecular Biology Institute, University of California, Los Angeles, California, USA
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Syeda K, Mohammed AM, Arora DK, Kowluru A. Glucotoxic conditions induce endoplasmic reticulum stress to cause caspase 3 mediated lamin B degradation in pancreatic β-cells: protection by nifedipine. Biochem Pharmacol 2013; 86:1338-46. [PMID: 23994168 DOI: 10.1016/j.bcp.2013.08.023] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Revised: 08/15/2013] [Accepted: 08/15/2013] [Indexed: 10/26/2022]
Abstract
Nuclear lamins form the lamina on the interior of the nuclear envelope, and are involved in the regulation of various cellular processes, including DNA replication and chromatin organization. Despite this evidence, little is known about potential alterations in nuclear metabolism, specifically lamin structure and integrity in isolated β-cells subjected to stress conditions, including chronic exposure to hyperglycemia (i.e., glucotoxicity). Herein, we investigated effects of glucotoxic conditions on the catalytic activation of caspase 3 and the associated degradation of one of its substrate proteins, namely lamin-B. We report that incubation of insulin-secreting INS-1 832/13 cells, normal rat islets or human islets under glucotoxic conditions (20 mM; 12-48 h) results in the degradation of native lamin B leading to accumulation of the degraded products in non-relevant cellular compartments, including cytosol. Moreover, the effects of high glucose on caspase 3 activation and lamin B degradation were mimicked by thapsigargin, a known inducer of endoplasmic reticulum stress (ER stress). Nifedipine, a known blocker of calcium channel activation, inhibited high glucose-induced caspase 3 activation and lamin B degradation in these cells. 4-Phenyl butyric acid, a known inhibitor of ER stress, markedly attenuated glucose-induced CHOP expression (ER stress marker), caspase 3 activation and lamin B degradation. We conclude that glucotoxic conditions promote caspase 3 activation and lamin B degradation, which may, in part, be due to increased ER stress under these conditions. We also provide further evidence to support beneficial effects of calcium channel blockers against metabolic dysfunction of the islet β-cell induced by hyperglycemic conditions.
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Affiliation(s)
- Khadija Syeda
- Beta-Cell Biochemistry Laboratory, John D. Dingell VA Medical Center and Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI 48201, United States
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Rivera-Torres J, Acín-Perez R, Cabezas-Sánchez P, Osorio FG, Gonzalez-Gómez C, Megias D, Cámara C, López-Otín C, Enríquez JA, Luque-García JL, Andrés V. Identification of mitochondrial dysfunction in Hutchinson-Gilford progeria syndrome through use of stable isotope labeling with amino acids in cell culture. J Proteomics 2013; 91:466-77. [PMID: 23969228 DOI: 10.1016/j.jprot.2013.08.008] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Revised: 08/01/2013] [Accepted: 08/08/2013] [Indexed: 01/03/2023]
Abstract
UNLABELLED Hutchinson-Gilford progeria syndrome (HGPS) is a rare segmental premature aging disorder that recapitulates some biological and physical aspects of physiological aging. The disease is caused by a sporadic dominant mutation in the LMNA gene that leads to the expression of progerin, a mutant form of lamin A that lacks 50 amino acids and retains a toxic farnesyl modification in its carboxy-terminus. However, the mechanisms underlying cellular damage and senescence and accelerated aging in HGPS are incompletely understood. Here, we analyzed fibroblasts from healthy subjects and HGPS patients using SILAC (stable isotope labeling with amino acids in cell culture). We found in HGPS cells a marked downregulation of mitochondrial oxidative phosphorylation proteins accompanied by mitochondrial dysfunction, a process thought to provoke broad organ decline during normal aging. We also found mitochondrial dysfunction in fibroblasts from adult progeroid mice expressing progerin (Lmna(G609G/G609G) knock-in mice) or prelamin A (Zmpste24-null mice). Analysis of tissues from these mouse models revealed that the damaging effect of these proteins on mitochondrial function is time- and dose-dependent. Mitochondrial alterations were not observed in the brain, a tissue with extremely low progerin expression that seems to be unaffected in HGPS. Remarkably, mitochondrial function was restored in progeroid mouse fibroblasts treated with the isoprenylation inhibitors FTI-277 or pravastatin plus zoledronate, which are being tested in HGPS clinical trials. Our results suggest that mitochondrial dysfunction contributes to premature organ decline and aging in HGPS. Beyond its effects on progeria, prelamin A and progerin may also contribute to mitochondrial dysfunction and organ damage during normal aging, since these proteins are expressed in cells and tissues from non-HGPS individuals, most prominently at advanced ages. BIOLOGICAL SIGNIFICANCE Mutations in LMNA or defective processing of prelamin A causes premature aging disorders, including Hutchinson-Gilford progeria syndrome (HGPS). Most HGPS patients carry in heterozygosis a de-novo point mutation (c.1824C>T: GGC>GGT; p.G608G) which causes the expression of the lamin A mutant protein called progerin. Despite the importance of progerin and prelamin A in accelerated aging, the underlying molecular mechanisms remain largely unknown. To tackle this question, we compared the proteome of skin-derived dermal fibroblast from HGPS patients and age-matched controls using quantitative stable isotope labeling with amino acids in cell culture (SILAC). Our results show a pronounced down-regulation of several components of the mitochondrial ATPase complex accompanied by up-regulation of some glycolytic enzymes. Accordingly, functional studies demonstrated mitochondrial dysfunction in HGPS fibroblasts. Moreover, our expression and functional studies using cellular and animal models confirmed that mitochondrial dysfunction is a feature of progeria which develops in a time- and dose-dependent manner. Finally, we demonstrate improved mitochondrial function in progeroid mouse cells treated with a combination of statins and aminobisphosphonates, two drugs that are being evaluated in ongoing HGPS clinical trials. Although further studies are needed to unravel the mechanisms through which progerin and prelamin A provoke mitochondrial abnormalities, our findings may pave the way to improved treatments of HGPS. These studies may also improve our knowledge of the mechanisms leading to mitochondrial dysfunction during normal aging, since both progerin and prelamin A have been found to accumulate during normal aging.
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Key Words
- ATP synthase, H+ transporting, mitochondrial F0 complex, subunit B1
- ATP synthase, H+ transporting, mitochondrial F1 complex, O subunit
- ATP synthase, H+ transporting, mitochondrial F1 complex, alpha subunit 1
- ATP synthase, H+ transporting, mitochondrial F1 complex, beta polypeptide
- ATP synthase, H+ transporting, mitochondrial F1 complex, gamma polypeptide
- ATP5A1
- ATP5B
- ATP5C1
- ATP5F1
- ATP5O
- Accelerated aging
- COX
- CS
- ENO2
- FTI
- FpSDH
- HGPS
- Hutchinson–Gilford progeria syndrome
- Lamin A
- MAF
- Mitochondrial dysfunction
- Molecular biology of aging
- OXPHOS
- PKM
- Progerin
- SILAC
- Zmpste24
- citrate synthase
- cytochrome c oxidase
- eIF2
- eIF4
- enolase 2
- eukaryotic translation initiation factor 2
- eukaryotic translation initiation factor 4
- farnesyltransferase inhibitor
- flavoprotein subunit of succinate dehydrogenase
- mTOR
- mammalian target of rapamycin
- mouse adult fibroblast
- oxidative phosphorylation
- p70S6K
- pyruvate kinase, muscle
- ribosomal protein S6 kinase, 70kDa, polypeptide 1
- stable isotope labeling with amino acids in cell culture
- zinc metalloproteinase STE24 homolog
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Affiliation(s)
- José Rivera-Torres
- Department of Epidemiology, Atherothrombosis and Imaging, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain.
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Węsierska-Gądek J, Walzi E, Dolečkova I, Schmid G. Oncogenes do not Fully Override Cell-intrinsic Traits: Pronounced Impact of the Cellular Programme. Cancer Microenviron 2009; 2:215-25. [PMID: 19731086 PMCID: PMC2756341 DOI: 10.1007/s12307-009-0024-9] [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] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/11/2009] [Accepted: 07/29/2009] [Indexed: 11/26/2022]
Abstract
Overexpression of p53 tumor suppressor protein in malignant cells induces cell cycle arrest, or alternatively, apoptosis thereby indicating that additional factors may contribute to the p53-mediated outcome. Comparison of the experimental protocols revealed that the construct encoding wild-type (wt) p53 was expressed in cells of different origin. Therefore, we decided to determine whether the intrinsic cellular program of primary cells of the same genetic background could have any effect on the oncogenic potential of mutated c-Ha-RAS and TP53. Primary rat cells (RECs) isolated from rat embryos of different age: at 13.5 gd (y) and 15.5 gd (o), were used for transfection. Immortalized rat cell clones overexpressing temperature-sensitive (ts) p53135val mutant and transformed cell clones after co-transfection with oncogenic c-Ha-Ras, were generated. The ts p53135Val mutant, switching between wt and mutant conformation, offers the possibility to study the role of p53 in cell cycle control in a model of malignant transformation in cells with the same genetic background. Surprisingly, the kinetics of cell proliferation at non-permissive temperature and that of cell cycle arrest at 32°C strongly differed between cell clones established from yRECs and oRECs. Furthermore, the kinetics of the re-enter of G1-arrested cells in the active cell cycle strongly differed between distinct cell clones. Finally, the susceptibility of immortalized and transformed cells to the pharmacological inhibitors of cyclin-dependent kinases (CDKs) considerably differed. Our results clearly show that overexpression of genes such as mutated TP53 and oncogenic c-Ha-RAS is not able to fully override the intrinsic cellular programme.
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Affiliation(s)
- Józefa Węsierska-Gądek
- Cell Cycle Regulation Group, Div. Institute of Cancer Research, Dept. of Medicine I, Medical University of Vienna, Borschkegasse 8 a, Vienna, A-1090 Austria
| | - Eva Walzi
- Cell Cycle Regulation Group, Div. Institute of Cancer Research, Dept. of Medicine I, Medical University of Vienna, Borschkegasse 8 a, Vienna, A-1090 Austria
| | - Iva Dolečkova
- Cell Cycle Regulation Group, Div. Institute of Cancer Research, Dept. of Medicine I, Medical University of Vienna, Borschkegasse 8 a, Vienna, A-1090 Austria
| | - Gerald Schmid
- Cell Cycle Regulation Group, Div. Institute of Cancer Research, Dept. of Medicine I, Medical University of Vienna, Borschkegasse 8 a, Vienna, A-1090 Austria
- Present Address: Christian Doppler Laboratory on Molecular Cancer Chemoprevention, Department of Medicine III, Medical University of Vienna, Währinger Gürtel 18-20, Vienna, A-1090 Austria
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