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Sivashanmugam M, J J, V U, K N S. Ornithine and its role in metabolic diseases: An appraisal. Biomed Pharmacother 2016; 86:185-194. [PMID: 27978498 DOI: 10.1016/j.biopha.2016.12.024] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 11/16/2016] [Accepted: 12/04/2016] [Indexed: 11/28/2022] Open
Abstract
Ornithine is a non-essential amino acid produced as an intermediate molecule in urea cycle. It is a key substrate for the synthesis of proline, polyamines and citrulline. Ornithine also plays an important role in the regulation of several metabolic processes leading to diseases like hyperorithinemia, hyperammonemia, gyrate atrophy and cancer in humans. However, the mechanism of action behind the multi-faceted roles of ornithine is yet to be unraveled completely. Several types of cancers are also characterized by excessive polyamine synthesis from ornithine by different rate limiting enzymes. Hence, in this review we aim to provide extensive insights on potential roles of ornithine in many of the disease related cellular processes and also on the structural features of ornithine interacting proteins, enabling development of therapeutic modalities.
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Affiliation(s)
- Muthukumaran Sivashanmugam
- Centre for Bioinformatics, Kamalnayan Bajaj Institute for Research in Vision and Ophthalmology, Vision Research Foundation, Chennai, India; School of Chemical and Biotechnology, SASTRA University, Thanjavur, India
| | - Jaidev J
- Centre for Bioinformatics, Kamalnayan Bajaj Institute for Research in Vision and Ophthalmology, Vision Research Foundation, Chennai, India
| | - Umashankar V
- Centre for Bioinformatics, Kamalnayan Bajaj Institute for Research in Vision and Ophthalmology, Vision Research Foundation, Chennai, India.
| | - Sulochana K N
- R.S. Mehta Jain Department of Biochemistry and Cell Biology, Kamalnayan Bajaj Institute for Research in Vision and Ophthalmology, Vision Research Foundation, Chennai, India.
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Interactions of diamines with adenosine-5'-triphosphate (ATP) in the systems including copper(II) ions. J Inorg Biochem 2016; 162:73-82. [PMID: 27289347 DOI: 10.1016/j.jinorgbio.2016.06.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 04/25/2016] [Accepted: 06/03/2016] [Indexed: 11/23/2022]
Abstract
Interactions were studied in the systems ATP/tn and ATP/Put (tn=1,3-diaminopropane, Put=putrescine) whereas the complexation reactions in ternary systems Cu(II)/ATP/tn and Cu(II)/ATP/Put. Results of the potentiometric and spectroscopic studies evidenced the formation of adducts of the type (ATP)Hx(PA), where PA=diamine. The thermodynamic stability of the complexes and the mode of interactions were determined. On the basis of analysis of changes in the positions of NMR signals, in the pH range of (ATP)H3(Put) formation, the preferred centres of the interaction between ATP and Put are the endocyclic nitrogen atoms from the nucleotide. On the other hand, the shorter diamine tn in the entire pH range reacts with the phosphate groups from ATP. The positive centres of noncovalent interactions are the protonated NHx+ groups from amines. In both complexes Cu(ATP)H2(tn) and Cu(ATP)H3(Put) formed in ternary systems at pH<6.5, the amines are in the outer sphere of coordination with the noncovalent interaction with anchoring Cu(ATP). Only the phosphate groups from the nucleotide take part in metalation. At higher pH in the range of Cu(ATP)(PA) complex formation, significant differences in the reactions of the two amines appear. The shorter one (tn) binds Cu(II) ions with two nitrogen atoms, while putrescine coordinates in the monofunctional mode, which is undoubtedly related to the differences in lengths of methylene chain. This explains the considerable differences in the stability of Cu(ATP)(tn) and Cu(ATP)(Put). In both complexes the nucleotide is coordinated through phosphate groups. SYNOPSIS As a result of noncovalent interactions ATP forms molecular complexes with 1,3-diaminopropane and 1,4-diaminobutane (putrescine). Significant differences in the mode of interactions between the two diamines were observed in ATP/diamine binary systems and in ternary systems Cu(II)/ATP/diamine, at high pH.
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Lozier AM, Rich ME, Grawe AP, Peck AS, Zhao P, Chang ATT, Bond JP, Sholler GS. Targeting ornithine decarboxylase reverses the LIN28/Let-7 axis and inhibits glycolytic metabolism in neuroblastoma. Oncotarget 2015; 6:196-206. [PMID: 25415050 PMCID: PMC4381588 DOI: 10.18632/oncotarget.2768] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 11/14/2014] [Indexed: 12/17/2022] Open
Abstract
LIN28 has emerged as an oncogenic driver in a number of cancers, including neuroblastoma (NB). Overexpression of LIN28 correlates with poor outcome in NB, therefore drugs that impact the LIN28/Let-7 pathway could be beneficial in treating NB patients. The LIN28/Let-7 pathway affects many cellular processes including the regulation of cancer stem cells and glycolytic metabolism. Polyamines, regulated by ornithine decarboxylase (ODC) modulate eIF-5A which is a direct regulator of the LIN28/Let-7 axis. We propose that therapy inhibiting ODC will restore balance to the LIN28/Let-7 axis, suppress glycolytic metabolism, and decrease MYCN protein expression in NB. Difluoromethylornithine (DFMO) is an inhibitor of ODC in clinical trials for children with NB. In vitro experiments using NB cell lines, BE(2)-C, SMS-KCNR, and CHLA90 show that DFMO treatment reduced LIN28B and MYCN protein levels and increased Let-7 miRNA and decreased neurosphere formation. Glycolytic metabolic activity decreased with DFMO treatment in vivo. Additionally, sensitivity to DFMO treatment correlated with LIN28B overexpression (BE(2)-C>SMS-KCNR>CHLA90). This is the first study to demonstrate that DFMO treatment restores balance to the LIN28/Let-7 axis and inhibits glycolytic metabolism and neurosphere formation in NB and that PET scans may be a meaningful imaging tool to evaluate the therapeutic effects of DFMO treatment.
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Affiliation(s)
- Ann M Lozier
- Pediatric Oncology Translational Research Program, Helen DeVos Children's Hospital, Grand Rapids, MI, USA
| | - Maria E Rich
- Pediatric Oncology Translational Research Program, Helen DeVos Children's Hospital, Grand Rapids, MI, USA
| | - Anissa Pedersen Grawe
- Pediatric Oncology Translational Research Program, Helen DeVos Children's Hospital, Grand Rapids, MI, USA
| | - Anderson S Peck
- Small Animal Imaging Facility, Van Andel Institute, Grand Rapids, MI, USA
| | - Ping Zhao
- Pediatric Oncology Translational Research Program, Helen DeVos Children's Hospital, Grand Rapids, MI, USA
| | | | - Jeffrey P Bond
- University of Vermont, Michigan State University, Grand Rapids, MI, USA
| | - Giselle Saulnier Sholler
- Pediatric Oncology Translational Research Program, Helen DeVos Children's Hospital, Grand Rapids, MI, USA. College of Human Medicine, Michigan State University, Grand Rapids, MI, USA
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Yco LP, Geerts D, Mocz G, Koster J, Bachmann AS. Effect of sulfasalazine on human neuroblastoma: analysis of sepiapterin reductase (SPR) as a new therapeutic target. BMC Cancer 2015; 15:477. [PMID: 26093909 PMCID: PMC4475614 DOI: 10.1186/s12885-015-1447-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 05/19/2015] [Indexed: 12/21/2022] Open
Abstract
Background Neuroblastoma (NB) is an aggressive childhood malignancy in children up to 5 years of age. High-stage tumors frequently relapse even after aggressive multimodal treatment, and then show therapy resistance, typically resulting in patient death. New molecular-targeted compounds that effectively suppress tumor growth and prevent relapse with more efficacy are urgently needed. We and others previously showed that polyamines (PA) like spermidine and spermine are essential for NB tumorigenesis and that DFMO, an inhibitor of the key PA synthesis gene product ODC, is effective both in vitro and in vivo, securing its evaluation in NB clinical trials. To find additional compounds interfering with PA biosynthesis, we tested sulfasalazine (SSZ), an FDA-approved salicylate-based anti-inflammatory and immune-modulatory drug, recently identified to inhibit sepiapterin reductase (SPR). We earlier presented evidence for a physical interaction between ODC and SPR and we showed that RNAi-mediated knockdown of SPR expression significantly reduced native ODC enzyme activity and impeded NB cell proliferation. Methods Human NB mRNA expression datasets in the public domain were analyzed using the R2 platform. Cell viability, isobologram, and combination index analyses as a result of SSZ treatment with our without DFMO were carried out in NB cell cultures. Molecular protein-ligand docking was achieved using the GRAMM algorithm. Statistical analyses were performed with the Kruskal-Wallis test, 2log Pearson test, and Student’s t test. Results In this study, we show the clinical relevance of SPR in human NB tumors. We found that high SPR expression is significantly correlated to unfavorable NB characteristics like high age at diagnosis, MYCN amplification, and high INSS stage. SSZ inhibits the growth of NB cells in vitro, presumably due to the inhibition of SPR as predicted by computational docking of SSZ into SPR. Importantly, the combination of SSZ with DFMO produces synergistic antiproliferative effects in vitro. Conclusions The results suggest the use of SSZ in combination with DFMO for further experiments, and possible prioritization as a novel therapy for the treatment of NB patients.
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Affiliation(s)
- Lisette P Yco
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, 301 Michigan Street, NE, Grand Rapids, MI, 49503, USA. .,Department of Pharmaceutical Sciences, The Daniel K. Inouye College of Pharmacy, University of Hawaii at Hilo, Hilo, HI, 96720, USA. .,Department of Molecular Biosciences and Bioengineering, College of Tropical Agriculture and Human Resources, University of Hawaii at Manoa, Honolulu, HI, 96822, USA.
| | - Dirk Geerts
- Department of Pediatric Oncology/Hematology, Sophia Children's Hospital, Erasmus University Medical Center, Rotterdam, GE, 3015, The Netherlands.
| | - Gabor Mocz
- Pacific Biosciences Research Center, University of Hawaii at Manoa, Honolulu, HI, 96822, USA.
| | - Jan Koster
- Department of Oncogenomics, Academic Medical Center, University of Amsterdam, Amsterdam, AZ, 1105, The Netherlands.
| | - André S Bachmann
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, 301 Michigan Street, NE, Grand Rapids, MI, 49503, USA. .,Department of Pharmaceutical Sciences, The Daniel K. Inouye College of Pharmacy, University of Hawaii at Hilo, Hilo, HI, 96720, USA. .,Department of Molecular Biosciences and Bioengineering, College of Tropical Agriculture and Human Resources, University of Hawaii at Manoa, Honolulu, HI, 96822, USA.
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Saulnier Sholler GL, Gerner EW, Bergendahl G, MacArthur RB, VanderWerff A, Ashikaga T, Bond JP, Ferguson W, Roberts W, Wada RK, Eslin D, Kraveka JM, Kaplan J, Mitchell D, Parikh NS, Neville K, Sender L, Higgins T, Kawakita M, Hiramatsu K, Moriya SS, Bachmann AS. A Phase I Trial of DFMO Targeting Polyamine Addiction in Patients with Relapsed/Refractory Neuroblastoma. PLoS One 2015; 10:e0127246. [PMID: 26018967 PMCID: PMC4446210 DOI: 10.1371/journal.pone.0127246] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 04/11/2015] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Neuroblastoma (NB) is the most common cancer in infancy and most frequent cause of death from extracranial solid tumors in children. Ornithine decarboxylase (ODC) expression is an independent indicator of poor prognosis in NB patients. This study investigated safety, response, pharmacokinetics, genetic and metabolic factors associated with ODC in a clinical trial of the ODC inhibitor difluoromethylornithine (DFMO) ± etoposide for patients with relapsed or refractory NB. METHODS AND FINDINGS Twenty-one patients participated in a phase I study of daily oral DFMO alone for three weeks, followed by additional three-week cycles of DFMO plus daily oral etoposide. No dose limiting toxicities (DLTs) were identified in patients taking doses of DFMO between 500-1500 mg/m2 orally twice a day. DFMO pharmacokinetics, single nucleotide polymorphisms (SNPs) in the ODC gene and urinary levels of substrates for the tissue polyamine exporter were measured. Urinary polyamine levels varied among patients at baseline. Patients with the minor T-allele at rs2302616 of the ODC gene had higher baseline levels (p=0.02) of, and larger decreases in, total urinary polyamines during the first cycle of DFMO therapy (p=0.003) and had median progression free survival (PFS) that was over three times longer, compared to patients with the major G allele at this locus although this last result was not statistically significant (p=0.07). Six of 18 evaluable patients were progression free during the trial period with three patients continuing progression free at 663, 1559 and 1573 days after initiating treatment. Median progression-free survival was less among patients having increased urinary polyamines, especially diacetylspermine, although this result was not statistically significant (p=0.056). CONCLUSIONS DFMO doses of 500-1500 mg/m2/day are safe and well tolerated in children with relapsed NB. Children with the minor T allele at rs2302616 of the ODC gene with relapsed or refractory NB had higher levels of urinary polyamine markers and responded better to therapy containing DFMO, compared to those with the major G allele at this locus. These findings suggest that this patient subset may display dependence on polyamines and be uniquely susceptible to therapies targeting this pathway. TRIAL REGISTRATION Clinicaltrials.gov NCT#01059071.
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Affiliation(s)
- Giselle L. Saulnier Sholler
- Helen DeVos Children’s Hospital, Grand Rapids, Michigan, United States of America
- College of Human Medicine, Michigan State University, Grand Rapids, Michigan, United States of America
| | - Eugene W. Gerner
- Cancer Prevention Pharmaceuticals, Tucson, Arizona, United States of America
| | - Genevieve Bergendahl
- Helen DeVos Children’s Hospital, Grand Rapids, Michigan, United States of America
| | - Robert B. MacArthur
- Cancer Prevention Pharmaceuticals, Tucson, Arizona, United States of America
| | - Alyssa VanderWerff
- Helen DeVos Children’s Hospital, Grand Rapids, Michigan, United States of America
| | - Takamaru Ashikaga
- Medical Biostatistics, University of Vermont, Burlington, Vermont, United States of America
| | - Jeffrey P. Bond
- Department of Microbiology and Molecular Genetics, University of Vermont College of Medicine, Burlington, Vermont, United States of America
| | - William Ferguson
- Cardinal Glennon Children's Hospital, St. Louis, Missouri, United States of America
| | - William Roberts
- University of California San Diego School of Medicine and Rady Children's Hospital, San Diego, California, United States of America
| | - Randal K. Wada
- Kapiolani Medical Center for Women and Children, Honolulu, Hawaii, United States of America
| | - Don Eslin
- Arnold Palmer Hospital for Children, Orlando, Florida, United States of America
| | - Jacqueline M. Kraveka
- Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Joel Kaplan
- Levine Children's Hospital, Charlotte, North Carolina, United States of America
| | - Deanna Mitchell
- Helen DeVos Children’s Hospital, Grand Rapids, Michigan, United States of America
| | - Nehal S. Parikh
- Connecticut Children's Medical Center, Hartford, Connecticut, United States of America
| | - Kathleen Neville
- Children's Mercy Hospitals and Clinics, Kansas City, Missouri, United States of America
| | - Leonard Sender
- Children’s Hospital of Orange County, Orange, California, United States of America
| | - Timothy Higgins
- Medical Biostatistics, University of Vermont, Burlington, Vermont, United States of America
| | - Masao Kawakita
- Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Kyoko Hiramatsu
- Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | | | - André S. Bachmann
- College of Human Medicine, Michigan State University, Grand Rapids, Michigan, United States of America
- University of Hawaii at Hilo, The Daniel K. Inouye College of Pharmacy, Hilo, Hawaii, United States of America
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Ramos-Molina B, López-Contreras AJ, Lambertos A, Dardonville C, Cremades A, Peñafiel R. Influence of ornithine decarboxylase antizymes and antizyme inhibitors on agmatine uptake by mammalian cells. Amino Acids 2015; 47:1025-34. [PMID: 25655388 DOI: 10.1007/s00726-015-1931-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 01/24/2015] [Indexed: 10/24/2022]
Abstract
Agmatine (4-aminobutylguanidine), a dicationic molecule at physiological pH, exerts relevant modulatory actions at many different molecular target sites in mammalian cells, having been suggested that the administration of this compound may have therapeutic interest. Several plasma membrane transporters have been implicated in agmatine uptake by mammalian cells. Here we report that in kidney-derived COS-7 cell line, at physiological agmatine levels, the general polyamine transporter participates in the plasma membrane translocation of agmatine, with an apparent Km of 44 ± 7 µM and Vmax of 17.3 ± 3.3 nmol h(-1) mg(-1) protein, but that at elevated concentrations, agmatine can be also taken up by other transport systems. In the first case, the physiological polyamines (putrescine, spermidine and spermine), several diguanidines and bis(2-aminoimidazolines) and the polyamine transport inhibitor AMXT-1501 markedly decreased agmatine uptake. In cells transfected with any of the three ornithine decarboxylase antizymes (AZ1, AZ2 and AZ3), agmatine uptake was dramatically reduced. On the contrary, transfection with antizyme inhibitors (AZIN1 and AZIN2) markedly increased the transport of agmatine. Furthermore, whereas putrescine uptake was significantly decreased in cells transfected with ornithine decarboxylase (ODC), the accumulation of agmatine was stimulated, suggesting a trans-activating effect of intracellular putrescine on agmatine uptake. All these results indicate that ODC and its regulatory proteins (antizymes and antizyme inhibitors) may influence agmatine homeostasis in mammalian tissues.
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Affiliation(s)
- Bruno Ramos-Molina
- Departamento de Bioquímica y Biología Molecular B e Inmunología, Facultad de Medicina, Universidad de Murcia, Campus de Espinardo, 30100, Murcia, Spain
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Bandino A, Geerts D, Koster J, Bachmann AS. Deoxyhypusine synthase (DHPS) inhibitor GC7 induces p21/Rb-mediated inhibition of tumor cell growth and DHPS expression correlates with poor prognosis in neuroblastoma patients. Cell Oncol (Dordr) 2014; 37:387-98. [PMID: 25315710 DOI: 10.1007/s13402-014-0201-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/22/2014] [Indexed: 11/29/2022] Open
Abstract
PURPOSE Neuroblastoma (NB) is an aggressive pediatric malignancy that typically occurs in infants and children under the age of 5 years. High-stage tumors relapse frequently even after aggressive multimodal treatment, resulting in therapy resistance and eventually in patient death. Clearly, new biologically-targeted drugs are needed that more efficiently suppress tumor growth and prevent relapse. We and others previously showed that polyamines such as spermidine play an essential role in NB tumorigenesis and that DFMO, an inhibitor of the central polyamine synthesis gene ODC, is effective in vitro and in vivo, prompting its evaluation in NB clinical trials. However, the specific molecular actions of polyamines remain poorly defined. Spermidine and deoxyhypusine synthase (DHPS) are essential components in the hypusination-driven post-translational activation of eukaryotic initiation factor 5A (eIF5A). METHODS We assessed the role of DHPS in NB and the impact of its inhibition by N(1)-guanyl-1,7-diaminoheptane (GC7) on tumor cell growth using cell proliferation assays, Western blot, immunofluorescence microscopy, and Affymetrix micro-array mRNA expression analyses in NB tumor samples. RESULTS We found that GC7 inhibits NB cell proliferation in a dose-dependent manner, through induction of the cell cycle inhibitor p21 and reduction of total and phosphorylated Rb proteins. Strikingly, high DHPS mRNA expression correlated significantly with unfavorable clinical parameters, including poor patient survival, in a cohort of 88 NB tumors (all P < 0.04). CONCLUSIONS These results suggest that spermidine and DHPS are key contributing factors in NB tumor proliferation through regulation of the p21/Rb signaling axis.
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Affiliation(s)
- Andrea Bandino
- Department of Pharmaceutical Sciences, The Daniel K. Inouye College of Pharmacy, University of Hawaii at Hilo, 34 Rainbow Drive, Hilo, HI, 96720, USA
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Modulation of intestinal epithelial cell proliferation, migration, and differentiation in vitro by Astragalus polysaccharides. PLoS One 2014; 9:e106674. [PMID: 25157577 PMCID: PMC4144960 DOI: 10.1371/journal.pone.0106674] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Accepted: 08/06/2014] [Indexed: 02/06/2023] Open
Abstract
Previous studies have shown that Astragalus polysaccharides (APS) can be used to treat general gastrointestinal disturbances including intestinal mucosal injury. However, the mechanism by which APS mediate this effect is unclear. In the present study, the effects of APS on proliferation, migration, and differentiation of intestinal epithelial cells (IEC-6) were assessed using an in vitro wounding model and colorimetric thiazolyl blue (MTT) assays. The effect of APS on IEC-6 cell differentiation was observed using a light microscope and scanning electron microscope, and the expression of differentiation-specific markers of IEC-6 cells, such as cytokeratin 18 (CK18), alkaline phosphatase (ALP), tight junction protein ZO-2, and sucrase-isomaltase (SI), was determined by immunofluorescence assay (IFA) and real-time PCR. In addition, APS-induced signaling pathways in IEC-6 cells were characterized. Our results indicated that APS significantly enhance migration and proliferation of IEC-6 cells in vitro. APS-treated IEC-6 cells have numerous microvilli on their apical surface and also highly express CK18, ALP, ZO-2, and SI. Moreover, APS-treated IEC-6 cells, in which the activity and expression level of ornithine decarboxylase (ODC) were significantly elevated, also exhibited an increase in cellular putrescine, whereas no significant increase in TGF-β levels was observed. These findings suggest that APS may enhance intestinal epithelial cell proliferation, migration, and differentiation in vitro by stimulating ODC gene expression and activity and putrescine production, independent of TGF-β. Exogenous administration of APS may provide a new approach for modulating intestinal epithelial wound restitution in vivo.
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Medina-Enríquez MM, Alcántara-Farfán V, Aguilar-Faisal L, Trujillo-Ferrara JG, Rodríguez-Páez L, Vargas-Ramírez AL. N-ω-chloroacetyl-l-ornithine, a new competitive inhibitor of ornithine decarboxylase, induces selective growth inhibition and cytotoxicity on human cancer cells versus normal cells. J Enzyme Inhib Med Chem 2014; 30:345-53. [PMID: 24939101 DOI: 10.3109/14756366.2014.926342] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Many cancer cells have high expression of ornithine decarboxylase (ODC) and there is a concerted effort to seek new inhibitors of this enzyme. The aim of the study was to initially characterize the inhibition properties, then to evaluate the cytotoxicity/antiproliferative cell based activity of N-ω-chloroacetyl-l-ornithine (NCAO) on three human cancer cell lines. Results showed NCAO to be a reversible competitive ODC inhibitor (Ki = 59 µM) with cytotoxic and antiproliferative effects, which were concentration- and time-dependent. The EC50,72h of NCAO was 15.8, 17.5 and 10.1 µM for HeLa, MCF-7 and HepG2 cells, respectively. NCAO at 500 µM completely inhibited growth of all cancer cells at 48 h treatment, with almost no effect on normal cells. Putrescine reversed NCAO effects on MCF-7 and HeLa cells, indicating that this antiproliferative activity is due to ODC inhibition.
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Affiliation(s)
- Miriam Marlene Medina-Enríquez
- Departamento de Bioquímica, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional. Prol. Carpio y Plan de Ayala , México, D.F.
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Chemoprevention of prostate cancer with the polyamine synthesis inhibitor difluoromethylornithine. Recent Results Cancer Res 2014; 202:115-20. [PMID: 24531785 DOI: 10.1007/978-3-642-45195-9_14] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
In vitro and in vivo preclinical results suggest that inhibition of polyamine synthesis inhibits the progression of prostate cancer. These findings has led to two clinical trials in patients at risk for invasive prostate cancer with difluoromethylornithine which specifically and irreversibly inhibits ornithine decarboxylase which catalyses the conversion of ornithine to putrescine the rate limiting step in polyamines synthesis. We have conducted a phase IIa one month and placebo randomized phase IIb 12 months trials in patients at increased risk for invasive prostate cancer. Favorable reduction in prostate polyamine levels and prostate volume was documented with no difference in clinical hearing changes. Patients with Gleason's VI lesions in a surveillance cohort would be appropriate candidates for a definitive risk reduction trial although the unavailability of validated biomarkers for invasive progression would require a large and lengthy study.
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Lange I, Geerts D, Feith DJ, Mocz G, Koster J, Bachmann AS. Novel interaction of ornithine decarboxylase with sepiapterin reductase regulates neuroblastoma cell proliferation. J Mol Biol 2013; 426:332-46. [PMID: 24096079 DOI: 10.1016/j.jmb.2013.09.037] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Revised: 09/21/2013] [Accepted: 09/25/2013] [Indexed: 01/24/2023]
Abstract
Ornithine decarboxylase (ODC) is the sentinel enzyme in polyamine biosynthesis. Both ODC and polyamines regulate cell division, proliferation, and apoptosis. Sepiapterin reductase (SPR) catalyzes the last step in the biosynthesis of tetrahydrobiopterin (BH4), an essential cofactor of nitric oxide synthase, and has been implicated in neurological diseases but not yet in cancer. In this study, we present compelling evidence that native ODC and SPR physically interact, and we defined the individual amino acid residues involved in both enzymes using in silico protein-protein docking simulations. The resulting heterocomplex is a surprisingly compact structure, featuring two energetically and structurally equivalent binding modes both in monomer and in dimer conformations. The novel interaction between ODC and SPR proteins was confirmed under physiological conditions by co-immunoprecipitation and co-localization in neuroblastoma (NB) cells. Importantly, we showed that siRNA (small interfering RNA)-mediated knockdown of SPR expression significantly reduced endogenous ODC enzyme activity in NB cells, thus demonstrating the biological relevance of the ODC-SPR interaction. Finally, in a cohort of 88 human NB tumors, we found that high SPR mRNA expression correlated significantly with poor survival prognosis using a Kaplan-Meier analysis (log-rank test, P=5 × 10(-4)), suggesting an oncogenic role for SPR in NB tumorigenesis. In conclusion, we showed that ODC binds SPR and thus propose a new concept in which two well-characterized biochemical pathways converge via the interaction of two enzymes. We identified SPR as a novel regulator of ODC enzyme activity and, based on clinical evidence, present a model in which SPR drives ODC-mediated malignant progression in NB.
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Affiliation(s)
- Ingo Lange
- Department of Pharmaceutical Sciences, The Daniel K. Inouye College of Pharmacy, University of Hawaii at Hilo, Hilo, HI 96720, USA
| | - Dirk Geerts
- Department of Pediatric Oncology/Hematology, Sophia Children's Hospital, Erasmus University Medical Center, 3015 GE Rotterdam, The Netherlands
| | - David J Feith
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Gabor Mocz
- Pacific Biosciences Research Center, University of Hawaii at Manoa, Honolulu, HI 96822, USA
| | - Jan Koster
- Department of Oncogenomics, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| | - André S Bachmann
- Department of Pharmaceutical Sciences, The Daniel K. Inouye College of Pharmacy, University of Hawaii at Hilo, Hilo, HI 96720, USA; Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96813, USA.
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