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Boland CR, Koi M, Hawn MT, Carethers JM, Yurgelun MB. Serendipity Strikes: How Pursuing Novel Hypotheses Shifted the Paradigm Regarding the Genetic Basis of Colorectal Cancer and Changed Cancer Therapy. Dig Dis Sci 2023; 68:3504-3513. [PMID: 37402979 PMCID: PMC11262588 DOI: 10.1007/s10620-023-08006-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/19/2023] [Indexed: 07/06/2023]
Abstract
In this installment of the "Paradigm Shifts in Perspective" series, the authors, all scientists who have been involved in colorectal cancer (CRC) research for most or all of their careers, have watched the field develop from early pathological descriptions of tumor formation to the current understanding of tumor pathogenesis that informs personalized therapies. We outline how our understanding of the pathogenetic basis of CRC began with seemingly isolated discoveries-initially with the mutations in RAS and the APC gene, the latter of which was initially found in the context of intestinal polyposis, to the more complex process of multistep carcinogenesis, to the chase for tumor suppressor genes, which led to the unexpected discovery of microsatellite instability (MSI). These discoveries enabled the authors to better understand how the DNA mismatch repair (MMR) system not only recognizes DNA damage but also responds to damage by DNA repair or by triggering apoptosis in the injured cell. This work served, in part, to link the earlier findings on the pathogenesis of CRC to the development of immune checkpoint inhibitors, which has been transformative-and curative-for certain types of CRCs and other cancers as well. These discoveries also highlight the circuitous routes that scientific progress takes, which can include thoughtful hypothesis testing and at other times recognizing the importance of seemingly serendipitous observations that substantially change the flow and direction of the discovery process. What has happened over the past 37 years was not predictable when this journey began, but it does speak to the power of careful scientific experimentation, following the facts, perseverance in the face of opposition, and the willingness to think outside of established paradigms.
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Affiliation(s)
| | | | - Mary T Hawn
- Department of Surgery, Stanford University School of Medicine, CJ Huang Bldg, Palo Alto, CA, 94306, USA
| | | | - Matthew B Yurgelun
- Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA, USA
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2
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Curtius K, Gupta S, Boland CR. Review article: Lynch Syndrome-a mechanistic and clinical management update. Aliment Pharmacol Ther 2022; 55:960-977. [PMID: 35315099 DOI: 10.1111/apt.16826] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 12/02/2021] [Accepted: 02/02/2022] [Indexed: 12/12/2022]
Abstract
BACKGROUND Lynch syndrome (LS) is an autosomal dominant familial condition caused by a pathogenic variant (PV) in a DNA mismatch repair gene, which then predisposes carriers to various cancers. AIM To review the pathogenesis, clinical presentation, differential diagnosis and clinical strategies for detection and management of LS. METHODS A narrative review synthesising knowledge from published literature, as well as current National Comprehensive Cancer Network guidelines for management of LS was conducted. RESULTS LS tumours are characterised by unique pathogenesis, ultimately resulting in hypermutation, microsatellite instability and high immunogenicity that has significant implications for cancer risk, clinical presentation, treatment and surveillance. LS is one of the most common hereditary causes of cancer, and about 1 in 279 individuals carry a PV in an LS gene that predisposes to associated cancers. Individuals with LS have increased risks for colorectal, endometrial and other cancers, with significant variation in lifetime risk by LS-associated gene. CONCLUSIONS As genetic testing becomes more widespread, the number of individuals identified with LS is expected to increase in the population. Understanding the pathogenesis of LS informs current strategies for detection and clinical management, and also guides future areas for clinical innovation. Unravelling the mechanisms by which these tumours evolve may help to more precisely tailor management by the gene involved.
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Affiliation(s)
- Kit Curtius
- Division of Biomedical Informatics, Department of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Samir Gupta
- Section of Gastroenterology, San Diego Veterans Affairs Healthcare System, San Diego, CA, USA.,Division of Gastroenterology, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - C Richard Boland
- Division of Gastroenterology, School of Medicine, University of California San Diego, La Jolla, CA, USA
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Raeker MO, Carethers JM. Immunological Features with DNA Microsatellite Alterations in Patients with Colorectal Cancer. JOURNAL OF CANCER IMMUNOLOGY 2020; 2:116-127. [PMID: 33000102 DOI: 10.33696/cancerimmunol.2.024] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Competent human DNA mismatch repair (MMR) corrects DNA polymerase mistakes made during cell replication to maintain complete DNA fidelity in daughter cells; faulty DNA MMR occurs in the setting of inflammation and neoplasia, creating base substitutions (e.g. point mutations) and frameshift mutations at DNA microsatellite sequences in progeny cells. Frameshift mutations at DNA microsatellite sequences are a detected biomarker termed microsatellite instability (MSI) for human disease, as this marker can prognosticate and determine therapeutic approaches for patients with cancer. There are two types of MSI: MSI-High (MSI-H), defined by frameshifts at mono- and di-nucleotide microsatellite sequences, and elevated microsatellite alterations at selected tetranucleotide repeats or EMAST, defined by frameshifts in di- and tetranucleotide microsatellite sequences but not mononucleotide sequences. Patients with colorectal cancers (CRCs) manifesting MSI-H demonstrate improved survival over patients without an MSI-H tumor, driven by the generation of immunogenic neoantigens caused by novel truncated proteins from genes whose sequences contain coding microsatellites; these patients' tumors contain hundreds of somatic mutations, and show responsiveness to treatment with immune checkpoint inhibitors. Patients with CRCs manifesting EMAST demonstrate poor survival over patients without an EMAST tumor, and may be driven by a more dominant defect in double strand break repair attributed to the MMR protein MSH3 over its frameshift correcting function; these patients' tumors often have a component of inflammation (and are also termed inflammation-associated microsatellite alterations) and show less somatic mutations and lack coding mononucleotide frameshift mutations that seem to generate the neoantigens seen in the majority of MSI-H tumors. Overall, both types of MSI are biomarkers that can prognosticate patients with CRC, can be tested for simultaneously in marker panels, and informs the approach to specific therapy including immunotherapy for their cancers.
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Affiliation(s)
- Maide O Raeker
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - John M Carethers
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan.,Department of Human Genetics and Rogel Cancer Center, University of Michigan, Ann Arbor, Michigan
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Komarova NL, Boland CR, Goel A, Wodarz D. Aspirin and the chemoprevention of cancers: A mathematical and evolutionary dynamics perspective. WILEY INTERDISCIPLINARY REVIEWS. SYSTEMS BIOLOGY AND MEDICINE 2020; 12:e1487. [PMID: 32163237 PMCID: PMC7486281 DOI: 10.1002/wsbm.1487] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 02/10/2020] [Accepted: 02/19/2020] [Indexed: 12/16/2022]
Abstract
Epidemiological data indicate that long-term low dose aspirin administration has a protective effect against the occurrence of colorectal cancer, both in sporadic and in hereditary forms of the disease. The mechanisms underlying this protective effect, however, are incompletely understood. The molecular events that lead to protection have been partly defined, but remain to be fully characterized. So far, however, approaches based on evolutionary dynamics have not been discussed much, but can potentially offer important insights. The aim of this review is to highlight this line of investigation and the results that have been obtained. A core observation in this respect is that aspirin has a direct negative impact on the growth dynamics of the cells, by influencing the kinetics of tumor cell division and death. We discuss the application of mathematical models to experimental data to quantify these parameter changes. We then describe further mathematical models that have been used to explore how these aspirin-mediated changes in kinetic parameters influence the probability of successful colony growth versus extinction, and how they affect the evolution of the tumor during aspirin administration. Finally, we discuss mathematical models that have been used to investigate the selective forces that can lead to the rise of mismatch-repair deficient cells in an inflammatory environment, and how this selection can be potentially altered through aspirin-mediated interventions. This article is categorized under: Models of Systems Properties and Processes > Mechanistic Models Analytical and Computational Methods > Analytical Methods Analytical and Computational Methods > Computational Methods.
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Affiliation(s)
- Natalia L Komarova
- Department of Mathematics, University of California Irvine, Irvine, California, USA
| | - C Richard Boland
- Department of Medicine, UCSD School of Medicine, San Diego, California, USA
| | - Ajay Goel
- Department of Molecular Diagnostics and Experimental Therapeutics, Beckman Research Institute, City of Hope Comprehensive Cancer Center, Biomedical Research Center, Monrovia, California, USA
| | - Dominik Wodarz
- Department of Population Health and Disease Prevention, Program in Public Health, Susan and Henry Samueli College of Health Sciences, University of California Irvine, Irvine, California, USA
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Raeker MÖ, Pierre-Charles J, Carethers JM. Tetranucleotide Microsatellite Mutational Behavior Assessed in Real Time: Implications for Future Microsatellite Panels. Cell Mol Gastroenterol Hepatol 2020; 9:689-704. [PMID: 31982570 PMCID: PMC7163322 DOI: 10.1016/j.jcmgh.2020.01.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 01/12/2020] [Accepted: 01/14/2020] [Indexed: 12/18/2022]
Abstract
BACKGROUND & AIMS Fifty percent of colorectal cancers show elevated microsatellite alterations at selected tetranucleotide repeats (EMAST) and are associated with inflammation, metastasis, and poor patient outcome. EMAST results from interleukin 6-induced nuclear-to-cytosolic displacement of the DNA mismatch repair protein Mutated S Homolog 3, allowing frameshifts of dinucleotide and tetranucleotide but not mononucleotide microsatellites. Unlike mononucleotide frameshifts that universally shorten in length, we previously observed expansion and contraction frameshifts at tetranucleotide sequences. Here, we developed cell models to assess tetranucleotide frameshifts in real time. METHODS We constructed plasmids containing native (AAAG)18 and altered-length ([AAAG]15 and [AAAG]12) human D9S242 locus that placed enhanced green fluorescent protein +1 bp/-1 bp out-of-frame for protein translation and stably transfected into DNA mismatch repair-deficient cells for clonal selection. We used flow cytometry to detect enhanced green fluorescent protein-positive cells to measure mutational behavior. RESULTS Frameshift mutation rates were 31.6 to 71.1 × 10-4 mutations/cell/generation and correlated with microsatellite length (r2 = 0.986, P = .0375). Longer repeats showed modestly higher deletion over insertion rates, with both equivalent for shorter repeats. Accumulation of more deletion frameshifts contributed to a distinct mutational bias for each length (overall: 77.8% deletions vs 22.2% insertions), likely owing to continual deletional mutation of insertions. Approximately 78.9% of observed frameshifts were 1 AAAG repeat, 16.1% were 2 repeats, and 5.1% were 3 or more repeats, consistent with a slipped strand mispairing mutation model. CONCLUSIONS Tetranucleotide frameshifts show a deletion bias and undergo more than 1 deletion event via intermediates, with insertions converted into deletions. Tetranucleotide markers added to traditional microsatellite instability panels will be able to determine both EMAST and classic microsatellite instability, but needs to be assessed by multiple markers to account for mutational behavior and intermediates.
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Affiliation(s)
- Maide Ö Raeker
- Division of Gastroenterology and Hepatology, University of Michigan, Ann Arbor, Michigan; Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Jovan Pierre-Charles
- Division of Gastroenterology and Hepatology, University of Michigan, Ann Arbor, Michigan; Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - John M Carethers
- Department of Human Genetics and Rogel Cancer Center, University of Michigan, Ann Arbor, Michigan.
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6
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Bouvet D, Bodo S, Munier A, Guillerm E, Bertrand R, Colas C, Duval A, Coulet F, Muleris M. Methylation Tolerance-Based Functional Assay to Assess Variants of Unknown Significance in the MLH1 and MSH2 Genes and Identify Patients With Lynch Syndrome. Gastroenterology 2019; 157:421-431. [PMID: 30998989 DOI: 10.1053/j.gastro.2019.03.071] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 03/07/2019] [Accepted: 03/29/2019] [Indexed: 12/12/2022]
Abstract
BACKGROUND & AIMS Approximately 75% of patients with suspected Lynch syndrome carry variants in MLH1 or MSH2, proteins encoded by these genes are required for DNA mismatch repair (MMR). However, 30% of these are variants of unknown significance (VUS). A assay that measures cell response to the cytotoxic effects of a methylating agent can determine the effects of VUS in MMR genes and identify patients with constitutional MMR-deficiency syndrome. We adapted this method to test the effects of VUS in MLH1 and MSH2 genes found in patients with suspected Lynch syndrome. METHODS We transiently expressed MLH1 or MSH2 variants in MLH1- or MSH2-null human colorectal cancer cell lines (HCT116 or LoVo), respectively. The MMR process causes death of cells with methylation-damaged DNA bases, so we measured proportions of cells that undergo death following exposure to the methylating agent; cells that escaped its toxicity were considered to have variants that affect function of the gene product. Using this assay, we analyzed 88 variants (mainly missense variants), comprising a validation set of 40 previously classified variants (19 in MLH1 and 21 in MSH2) and a prospective set of 48 VUS (25 in MLH1 and 23 in MSH2). Prediction scores were calculated for all VUS according to the recommendations of the American College of Medical Genetics and Genomics, based on clinical, somatic, in silico, population, and functional data. RESULTS The assay correctly classified 39 of 40 variants in the validation set. The assay identified 12 VUS that did alter function of the gene product and 28 VUS that did not; the remaining 8 VUS had intermediate effects on MMR capacity and could not be classified. Comparison of assay results with prediction scores confirmed the ability of the assay to discriminate VUS that affected the function of the gene products from those that did not. CONCLUSIONS Using an assay that measures the ability of the cells to undergo death following DNA damage induction by a methylating agent, we were able to assess whether variants in MLH1 and MSH2 cause defects in DNA MMR. This assay might be used to help assessing the pathogenicity of VUS in MLH1 and MSH2 found in patients with suspected Lynch syndrome.
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Affiliation(s)
- Delphine Bouvet
- Sorbonne Université, Inserm, Centre de Recherche Saint-Antoine, CRSA, Paris, France; Equipe labellisée par la Ligue Nationale contre le Cancer, Paris, France
| | - Sahra Bodo
- Sorbonne Université, Inserm, Centre de Recherche Saint-Antoine, CRSA, Paris, France; Equipe labellisée par la Ligue Nationale contre le Cancer, Paris, France
| | - Annie Munier
- Sorbonne Université, Inserm, Centre de recherche Saint-Antoine, UMS30-LUMIC, Plateforme de Cytométrie en Flux CISA, site Saint-Antoine, Paris, France
| | - Erell Guillerm
- Sorbonne Université, Inserm, Centre de Recherche Saint-Antoine, CRSA, Paris, France; Equipe labellisée par la Ligue Nationale contre le Cancer, Paris, France; Genetics Department, AP-HP, Hôpital Universitaire Pitié-Salpétrière, Paris, France
| | - Romane Bertrand
- Sorbonne Université, Inserm, Centre de Recherche Saint-Antoine, CRSA, Paris, France; Equipe labellisée par la Ligue Nationale contre le Cancer, Paris, France
| | - Chrystelle Colas
- Sorbonne Université, Inserm, Centre de Recherche Saint-Antoine, CRSA, Paris, France; Equipe labellisée par la Ligue Nationale contre le Cancer, Paris, France; Institut Curie, Paris Sciences Lettres Research University, Department of Genetics, Paris, France
| | - Alex Duval
- Equipe labellisée par la Ligue Nationale contre le Cancer, Paris, France; Sorbonne Université, Inserm, Centre de Recherche Saint-Antoine, CRSA, AP-HP, Biochimie, biologie moléculaire, Paris, France
| | - Florence Coulet
- Sorbonne Université, Inserm, Centre de Recherche Saint-Antoine, CRSA, Paris, France; Equipe labellisée par la Ligue Nationale contre le Cancer, Paris, France; Genetics Department, AP-HP, Hôpital Universitaire Pitié-Salpétrière, Paris, France
| | - Martine Muleris
- Sorbonne Université, Inserm, Centre de Recherche Saint-Antoine, CRSA, Paris, France; Equipe labellisée par la Ligue Nationale contre le Cancer, Paris, France.
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Reilly NM, Novara L, Di Nicolantonio F, Bardelli A. Exploiting DNA repair defects in colorectal cancer. Mol Oncol 2019; 13:681-700. [PMID: 30714316 PMCID: PMC6441925 DOI: 10.1002/1878-0261.12467] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 01/11/2019] [Accepted: 01/19/2019] [Indexed: 02/06/2023] Open
Abstract
Colorectal cancer (CRC) is the third leading cause of cancer-related deaths worldwide. Therapies that take advantage of defects in DNA repair pathways have been explored in the context of breast, ovarian, and other tumor types, but not yet systematically in CRC. At present, only immune checkpoint blockade therapies have been FDA approved for use in mismatch repair-deficient colorectal tumors. Here, we discuss how systematic identification of alterations in DNA repair genes could provide new therapeutic opportunities for CRCs. Analysis of The Cancer Genome Atlas Colon Adenocarcinoma (TCGA-COAD) and Rectal Adenocarcinoma (TCGA-READ) PanCancer Atlas datasets identified 141 (out of 528) cases with putative driver mutations in 29 genes associated with DNA damage response and repair, including the mismatch repair and homologous recombination pathways. Genetic defects in these pathways might confer repair-deficient characteristics, such as genomic instability in the absence of homologous recombination, which can be exploited. For example, inhibitors of poly(ADP)-ribose polymerase are effectively used to treat cancers that carry mutations in BRCA1 and/or BRCA2 and have shown promising results in CRC preclinical studies. HR deficiency can also occur in cells with no detectable BRCA1/BRCA2 mutations but exhibiting BRCA-like phenotypes. DNA repair-targeting therapies, such as ATR and CHK1 inhibitors (which are most effective against cancers carrying ATM mutations), can be used in combination with current genotoxic chemotherapies in CRCs to further improve therapy response. Finally, therapies that target alternative DNA repair mechanisms, such as thiopurines, also have the potential to confer increased sensitivity to current chemotherapy regimens, thus expanding the spectrum of therapy options and potentially improving clinical outcomes for CRC patients.
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Affiliation(s)
- Nicole M. Reilly
- Fondazione Piemontese per la Ricerca sul Cancro ONLUSCandioloItaly
| | - Luca Novara
- Candiolo Cancer InstituteFPO‐IRCCSCandioloItaly
| | - Federica Di Nicolantonio
- Candiolo Cancer InstituteFPO‐IRCCSCandioloItaly
- Department of OncologyUniversity of TorinoCandioloItaly
| | - Alberto Bardelli
- Candiolo Cancer InstituteFPO‐IRCCSCandioloItaly
- Department of OncologyUniversity of TorinoCandioloItaly
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Weeramange C, Lansakara A, Dallman J, Nguyen T, Hulangamuwa W, Rafferty RJ. New methods to assess 6-thiopurine toxicity and expanding its therapeutic application to pancreatic cancer via small molecule potentiators. MEDCHEMCOMM 2019; 10:717-725. [PMID: 31191862 DOI: 10.1039/c9md00010k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 03/14/2019] [Indexed: 01/16/2023]
Abstract
6-Thiopurine (6TP) is a potent cytotoxic agent that is a clinically prescribed anti-metabolite employed in the treatment of numerous blood cancers since 1952. However, its reported severe toxicities limit its general usage in the clinic. We previously have undertaken investigations into identifying the mode of toxicity for 6TP, and have found that the oxidative metabolites of 6TP, specifically 6-thiouric acid (6TU), is responsible for the in vitro inhibition of UDP-glucose dehydrogenase (UDPGDH) in a UV-vis method. In this method, inhibition was quantified through the quantification of NADH production, however, purines absorb at the same wavelength and thereby can interfere with the NADH detection. Herein, we report a HPLC method that allows for direct quantification of UDP-glucuronic acid, product from UDPGDH, for the assessment of inhibition towards UDPGDH with no interference from purines. In this method it was revealed that 6TP possesses a greater inhibitory properties than previously observed; 111 vs. 288 μM. Building upon the data collected from a previously performed rat hepatocyte study, which correlated our in vitro to in vivo inhibition theories about UDPGDH, we have developed a bio-mimic in vitro assay to aid in the inhibitory assessment of 6TP and analogs. In our efforts to expand the use of 6TP, and analogs constructed, our laboratory has undertaken a screening campaign to identify small molecule potentiators that work in synergy with 6TP in other types of cancers. Three chalcone-based compounds have been discovered through our total synthesis campaign of uvaretin, and it has been found that 11c has strong synergism with 6TP in the pancreatic cancer cell line MIA PaCa-2. Through the work presented herein, we reveal new methods to assess toxicity of 6TP and future analogs and new small molecules that work in synergy to expand the therapeutic applications of this neglected cytotoxic agent.
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Affiliation(s)
- Chamitha Weeramange
- Department of Chemistry , Kansas State University , 1212 Mid-Campus Drive North , Manhattan , KS 66506 , USA
| | - Ashabha Lansakara
- Department of Chemistry , Kansas State University , 1212 Mid-Campus Drive North , Manhattan , KS 66506 , USA
| | - Johnathan Dallman
- Department of Chemistry , Kansas State University , 1212 Mid-Campus Drive North , Manhattan , KS 66506 , USA
| | - Thi Nguyen
- Department of Chemistry , Kansas State University , 1212 Mid-Campus Drive North , Manhattan , KS 66506 , USA
| | - Wasundara Hulangamuwa
- Department of Chemistry , Kansas State University , 1212 Mid-Campus Drive North , Manhattan , KS 66506 , USA
| | - Ryan J Rafferty
- Department of Chemistry , Kansas State University , 1212 Mid-Campus Drive North , Manhattan , KS 66506 , USA
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9
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Torres Hernandez AX, Weeramange CJ, Desman P, Fatino A, Haney O, Rafferty RJ. Efforts in redesigning the antileukemic drug 6-thiopurine: decreasing toxic side effects while maintaining efficacy. MEDCHEMCOMM 2018; 10:169-179. [PMID: 30774864 DOI: 10.1039/c8md00463c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 12/15/2018] [Indexed: 01/14/2023]
Abstract
6-Thiopurine (6TP) is a currently prescribed drug in the treatment of diseases ranging from Crohn's disease to acute lymphocytic leukemia. While its potent mode of action is through incorporation into DNA as a thiol mimic of deoxyguanosine, severe toxicities are associated with its administration which hinder the potential therapeutic application. We have previously reported in vitro that the oxidative metabolites of 6TP, specifically 6-thiouric acid (6TU, K i 7 μM), are potent inhibitors of UDP-glucose dehydrogenase (UDPGDH), an enzyme that is responsible for the formation of UDP-glucuronic acid (UDPGA), an essential substrate that is used in detoxification processes in the liver. An in vivo investigation was undertaken to probe if 6TU inhibits UDPGDH in rat hepatocytes, and it was observed that 6TU does greatly suppress the conjugation of bilirubin with UDPGA. The failed excretion of bilirubin is linked to a majority of the reported toxicities associated with 6TP administration. Efforts were undertaken for the construction of 6TP analogs, substituted at the C8 position, to reduce inhibition of UDPGDH while retaining therapeutic efficacy. Three new 6TP analogs bearing a halogen (Br, Cl, and F) at the C8 position have been achieved over five-synthetic steps in overall yields of 16 to 32%. Each of these analogs were shown to have reduced inhibition towards UDPGDH, with K i values of 192, 163, 215 μM, respectively. In addition, the bromine, chlorine, and fluorine analogs were shown to possess cytotoxicity towards the REH cell line (acute lymphocytic leukemia) having IC50 values of 9.54 μM (±0.97), 3.95 μM (±1.94), and 4.71 μM (±1.40), respectively. These three new 6TP analogs represent the first steps in the redesign of this potent anticancer agent into a better drug that possesses reduced toxic side effects while retaining therapeutic potency.
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Affiliation(s)
- Arnaldo X Torres Hernandez
- Department of Chemistry , Pontifical Catholic University of Puerto Rico , 2250 Boulevard Luis A. Ferré Aguayo, Suite 626 , Ponce , PR 00717-0777 , Puerto Rico.,Department of Chemistry , Kansas State University , 1212 Mid-Campus Drive North , Manhattan , KS 66506 , USA .
| | - Chamitha J Weeramange
- Department of Chemistry , Kansas State University , 1212 Mid-Campus Drive North , Manhattan , KS 66506 , USA .
| | - Prathibha Desman
- Department of Chemistry , Kansas State University , 1212 Mid-Campus Drive North , Manhattan , KS 66506 , USA .
| | - Anthony Fatino
- Department of Chemistry , Kansas State University , 1212 Mid-Campus Drive North , Manhattan , KS 66506 , USA .
| | - Olivia Haney
- Department of Chemistry , Kansas State University , 1212 Mid-Campus Drive North , Manhattan , KS 66506 , USA .
| | - Ryan J Rafferty
- Department of Chemistry , Kansas State University , 1212 Mid-Campus Drive North , Manhattan , KS 66506 , USA .
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10
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Boland PM, Yurgelun MB, Boland CR. Recent progress in Lynch syndrome and other familial colorectal cancer syndromes. CA Cancer J Clin 2018; 68:217-231. [PMID: 29485237 PMCID: PMC5980692 DOI: 10.3322/caac.21448] [Citation(s) in RCA: 100] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 01/08/2018] [Accepted: 01/31/2018] [Indexed: 12/16/2022] Open
Abstract
The current understanding of familial colorectal cancer was limited to descriptions of affected pedigrees until the early 1990s. A series of landscape-altering discoveries revealed that there were distinct forms of familial cancer, and most were related to genes previously not known to be involved in human disease. This review largely focuses on advances in our understanding of Lynch syndrome because of the unique relationship of this disease to defective DNA mismatch repair and the clinical implications this has for diagnostics, prevention, and therapy. Recent advances have occurred in our understanding of the epidemiology of this disease, and the advent of broad genetic panels has altered the approach to germline and somatic diagnoses for all of the familial colorectal cancer syndromes. Important advances have been made toward a more complete mechanistic understanding of the pathogenesis of neoplasia in the setting of Lynch syndrome, and these advances have important implications for prevention. Finally, paradigm-shifting approaches to treatment of Lynch-syndrome and related tumors have occurred through the development of immune checkpoint therapies for hypermutated cancers. CA Cancer J Clin 2018;68:217-231. © 2018 American Cancer Society.
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Affiliation(s)
- Patrick M Boland
- Assistant Professor, Department of Medicine, Roswell Park Cancer Institute, Buffalo, NY
| | - Matthew B Yurgelun
- Assistant Professor of Medicine, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA
| | - C Richard Boland
- Professor, Department of Medicine, University of California at San Diego School of Medicine, San Diego, CA
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11
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Liu X, Liu S, Lei J, Zou L, Xiao L, Zhang G. Methylation and expression of mismatch repair gene human mutS homolog 2 in myelodysplastic syndromes. Exp Ther Med 2018; 15:500-505. [PMID: 29387203 DOI: 10.3892/etm.2017.5402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 10/26/2017] [Indexed: 11/06/2022] Open
Abstract
As a highly heterogeneous disease, the pathogenesis of myelodysplastic syndrome (MDS) has not been well defined. In the present study, human mutS homolog 2 (hMSH2) promoter methylation was detected with methylation-specific polymerase chain reaction (PCR). The function of hMSH2 was analyzed by microsatellite instability (MSI) detection of BAT-26, and hMSH2 expression was evaluated using reverse transcription-quantitative PCR in 60 patients with MDS. The results revealed methylation of the hMSH2 promoter in 18 patients with MDS who have an overall prevalence of 30% (95% confidence interval, 18.4-41.6%). Among the patients with hMSH2 methylation, 2 patients exhibited MSI. It was demonstrated that hMSH2 promoter methylation was increased in MDS with an increase in Revised International Prognostic Scoring System (IPSS-R) risk, and patients with higher hMSH2 promoter methylation had shorter overall survival by Kaplan-Meier analysis (P=0.011). In addition, it was also observed that decreased hMSH2 mRNA expression was associated with high IPSS-R risk group (high/very high vs. intermediate, P=0.003), and hMSH2 mRNA expression in CD34 positive bone marrow cells was lower compared with that in CD34 negative cells of patients with MDS (P=0.029). Methylation of hMSH2 may be valuable for prognostic evaluation and progression prediction of MDS. Furthermore, hMSH2 may serve a key function in the pathogenesis and prognosis of MDS.
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Affiliation(s)
- Xiaoliu Liu
- Department of Hematology, The Affiliated Changsha Hospital, Hunan Normal University, Changsha, Hunan 410006, P.R. China
| | - Sufang Liu
- Division of Hematology, Institute of Molecular Hematology, The Second Xiang-Ya Hospital, Central South University, Changsha, Hunan 410011, P.R. China
| | - Jian Lei
- Department of Pathology, The Affiliated Tumor Hospital, Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, P.R. China
| | - Lixin Zou
- Department of Hematology, The Affiliated Changsha Hospital, Hunan Normal University, Changsha, Hunan 410006, P.R. China
| | - Le Xiao
- Division of Hematology, Institute of Molecular Hematology, The Second Xiang-Ya Hospital, Central South University, Changsha, Hunan 410011, P.R. China
| | - Guangsen Zhang
- Division of Hematology, Institute of Molecular Hematology, The Second Xiang-Ya Hospital, Central South University, Changsha, Hunan 410011, P.R. China
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Inhibition of UDP-glucose dehydrogenase by 6-thiopurine and its oxidative metabolites: Possible mechanism for its interaction within the bilirubin excretion pathway and 6TP associated liver toxicity. J Pharm Biomed Anal 2017; 151:106-115. [PMID: 29324279 DOI: 10.1016/j.jpba.2017.12.058] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 12/24/2017] [Accepted: 12/29/2017] [Indexed: 02/07/2023]
Abstract
6-Thiopurine (6TP) is an actively prescribed drug in the treatment of various diseases ranging from Crohn's disease and other inflammatory diseases to acute lymphocytic leukemia and non-Hodgkin's leukemia. While 6TP has beneficial therapeutic uses, severe toxicities are also reported with its use, such as jaundice and liver toxicity. While numerous investigations into the mode in which toxicity originates has been undertaken. None have investigated the effects of inhibition towards UDP-Glucose Dehydrogenase (UDPGDH), an oxidative enzyme responsible for UDP-glucuronic acid (UDPGA) formation or UDP-Glucuronosyl transferase (UGT1A1), which is responsible for the conjugation of bilirubin with UDPGA for excretion. Failure to excrete bilirubin leads to jaundice and liver toxicity. We proposed that either 6TP or its primary oxidative excretion metabolites inhibit one or both of these enzymes, resulting in the observed toxicity from 6TP administration. Inhibition analysis of these purines revealed that 6-thiopurine has weak to no inhibition towards UDPGDH with a Ki of 288 μM with regard to varying UDP-glucose, but 6-thiouric (primary end metabolite, fully oxidized at carbon 2 and 8, and highly retained by the body) has a near six-fold increased inhibition towards UDPGDH with a Ki of 7 μM. Inhibition was also observed by 6-thioxanthine (oxidized at carbon 2) and 8-OH-6TP with Ki values of 54 and 14 μM, respectively. Neither 6-thiopurine or its excretion metabolites were shown to inhibit UGT1A1. Our results show that the C2 and C8 positions of 6TP are pivotal in said inhibition towards UDPGDH and have no effect upon UGT1A1, and that blocking C8 could lead to new analogs with reduced, if not eliminated jaundice and liver toxicities.
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Jia P, Chastain M, Zou Y, Her C, Chai W. Human MLH1 suppresses the insertion of telomeric sequences at intra-chromosomal sites in telomerase-expressing cells. Nucleic Acids Res 2017; 45:1219-1232. [PMID: 28180301 PMCID: PMC5388398 DOI: 10.1093/nar/gkw1170] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 10/26/2016] [Accepted: 11/09/2016] [Indexed: 11/29/2022] Open
Abstract
Aberrant formation of interstitial telomeric sequences (ITSs) promotes genome instabilities. However, it is unclear how aberrant ITS formation is suppressed in human cells. Here, we report that MLH1, a key protein involved in mismatch repair (MMR), suppresses telomeric sequence insertion (TSI) at intra-chromosomal regions. The frequency of TSI can be elevated by double-strand break (DSB) inducer and abolished by ATM/ATR inhibition. Suppression of TSI requires MLH1 recruitment to DSBs, indicating that MLH1's role in DSB response/repair is important for suppressing TSI. Moreover, TSI requires telomerase activity but is independent of the functional status of p53 and Rb. Lastly, we show that TSI is associated with chromosome instabilities including chromosome loss, micronuclei formation and chromosome breakage that are further elevated by replication stress. Our studies uncover a novel link between MLH1, telomerase, telomere and genome stability.
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Affiliation(s)
- Pingping Jia
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, Spokane, WA, USA
| | - Megan Chastain
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, Spokane, WA, USA
| | - Ying Zou
- Cytogenetics Laboratory, Department of Pathology, the University of Maryland School of Medicine, Baltimore, MD, USA
| | - Chengtao Her
- School of Molecular Biosciences, Washington State University, Pullman, WA, USA
| | - Weihang Chai
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, Spokane, WA, USA
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Koi M, Carethers JM. The colorectal cancer immune microenvironment and approach to immunotherapies. Future Oncol 2017; 13:1633-1647. [PMID: 28829193 DOI: 10.2217/fon-2017-0145] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Affiliation(s)
- Minoru Koi
- Division of Gastroenterology, Department of Internal Medicine & Comprehensive Cancer Center, University of Michigan, Ann Arbor, MI 48109, USA
| | - John M Carethers
- Division of Gastroenterology, Department of Internal Medicine & Comprehensive Cancer Center, University of Michigan, Ann Arbor, MI 48109, USA.,Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109, USA
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Zhang CM, Lv JF, Gong L, Yu LY, Chen XP, Zhou HH, Fan L. Role of Deficient Mismatch Repair in the Personalized Management of Colorectal Cancer. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2016; 13:ijerph13090892. [PMID: 27618077 PMCID: PMC5036725 DOI: 10.3390/ijerph13090892] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 09/01/2016] [Accepted: 09/05/2016] [Indexed: 02/06/2023]
Abstract
Colorectal cancer (CRC) represents the third most common type of cancer in developed countries and one of the leading causes of cancer deaths worldwide. Personalized management of CRC has gained increasing attention since there are large inter-individual variations in the prognosis and response to drugs used to treat CRC owing to molecular heterogeneity. Approximately 15% of CRCs are caused by deficient mismatch repair (dMMR) characterized by microsatellite instability (MSI) phenotype. The present review is aimed at highlighting the role of MMR status in informing prognosis and personalized treatment of CRC including adjuvant chemotherapy, targeted therapy, and immune checkpoint inhibitor therapy to guide the individualized therapy of CRC.
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Affiliation(s)
- Cong-Min Zhang
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha 410008, China.
- Institute of Clinical Pharmacology, Central South University, Hunan Key Laboratory of Pharmacogenetics, Changsha 410078, China.
| | - Jin-Feng Lv
- Department of Pharmacy, Xiangya Hospital, Central South University, Changsha 410008, China.
- Institute of Hospital Pharmacy, Central South University, Changsha 410008, China.
| | - Liang Gong
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha 410008, China.
- Institute of Clinical Pharmacology, Central South University, Hunan Key Laboratory of Pharmacogenetics, Changsha 410078, China.
| | - Lin-Yu Yu
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha 410008, China.
- Institute of Clinical Pharmacology, Central South University, Hunan Key Laboratory of Pharmacogenetics, Changsha 410078, China.
| | - Xiao-Ping Chen
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha 410008, China.
- Institute of Clinical Pharmacology, Central South University, Hunan Key Laboratory of Pharmacogenetics, Changsha 410078, China.
| | - Hong-Hao Zhou
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha 410008, China.
- Institute of Clinical Pharmacology, Central South University, Hunan Key Laboratory of Pharmacogenetics, Changsha 410078, China.
| | - Lan Fan
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha 410008, China.
- Institute of Clinical Pharmacology, Central South University, Hunan Key Laboratory of Pharmacogenetics, Changsha 410078, China.
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Affiliation(s)
- John M. Carethers
- Division of Gastroenterology, Department of Internal Medicine, University of Michigan, 3101 Taubman Center, 1500 East Medical Center Drive, Ann Arbor, MI 48109-5368, USA
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Carethers JM. HEREDITARY, SPORADIC AND METASTATIC COLORECTAL CANCER ARE COMMONLY DRIVEN BY SPECIFIC SPECTRUMS OF DEFECTIVE DNA MISMATCH REPAIR COMPONENTS. TRANSACTIONS OF THE AMERICAN CLINICAL AND CLIMATOLOGICAL ASSOCIATION 2016; 127:81-97. [PMID: 28066040 PMCID: PMC5216503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
DNA mismatch repair (MMR) is one of several human cell mechanisms utilized to repair mutable mistakes within DNA, particularly after DNA is replicated. MMR function is dependent upon heterodimerization of specific MMR proteins that can recognize base-base mispairs as well as frameshifts at microsatellite sequences, followed by the triggering of other complementary proteins that execute excision and repair or initiate cell demise if repair is futile. MMR function is compromised in specific disease states, all of which can be biochemically recognized by faulty repair of microsatellite sequences, causing microsatellite instability. Germline mutation of an MMR gene causes Lynch syndrome, the most common inherited form of colorectal cancer (CRC), and biallelic germline mutations cause the rare constitutional mismatch repair deficiency syndrome. Somatic inactivation of MMR through epigenetic mechanisms is observed in 15% of sporadic CRC, and a smaller portion of CRCs possess biallelic somatic mutations. A novel inflammation-driven nuclear-to-cytoplasmic shift of the specific MMR protein hMSH3 is seen in up to 60% of sporadic CRCs that associates with metastasis and poor patient prognosis, unlike improved outcome when MMR is genetically inactivated. The mechanism for MMR inactication as well as the component affected dictates the clinical spectrum and clinical response for patients.
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Bodo S, Colas C, Buhard O, Collura A, Tinat J, Lavoine N, Guilloux A, Chalastanis A, Lafitte P, Coulet F, Buisine MP, Ilencikova D, Ruiz-Ponte C, Kinzel M, Grandjouan S, Brems H, Lejeune S, Blanché H, Wang Q, Caron O, Cabaret O, Svrcek M, Vidaud D, Parfait B, Verloes A, Knappe UJ, Soubrier F, Mortemousque I, Leis A, Auclair-Perrossier J, Frébourg T, Fléjou JF, Entz-Werle N, Leclerc J, Malka D, Cohen-Haguenauer O, Goldberg Y, Gerdes AM, Fedhila F, Mathieu-Dramard M, Hamelin R, Wafaa B, Gauthier-Villars M, Bourdeaut F, Sheridan E, Vasen H, Brugières L, Wimmer K, Muleris M, Duval A. Diagnosis of Constitutional Mismatch Repair-Deficiency Syndrome Based on Microsatellite Instability and Lymphocyte Tolerance to Methylating Agents. Gastroenterology 2015; 149:1017-29.e3. [PMID: 26116798 DOI: 10.1053/j.gastro.2015.06.013] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Revised: 05/21/2015] [Accepted: 06/13/2015] [Indexed: 12/02/2022]
Abstract
BACKGROUND & AIMS Patients with bi-allelic germline mutations in mismatch repair (MMR) genes (MLH1, MSH2, MSH6, or PMS2) develop a rare but severe variant of Lynch syndrome called constitutional MMR deficiency (CMMRD). This syndrome is characterized by early-onset colorectal cancers, lymphomas or leukemias, and brain tumors. There is no satisfactory method for diagnosis of CMMRD because screens for mutations in MMR genes are noninformative for 30% of patients. MMR-deficient cancer cells are resistant to genotoxic agents and have microsatellite instability (MSI), due to accumulation of errors in repetitive DNA sequences. We investigated whether these features could be used to identify patients with CMMRD. METHODS We examined MSI by PCR analysis and tolerance to methylating or thiopurine agents (functional characteristics of MMR-deficient tumor cells) in lymphoblastoid cells (LCs) from 3 patients with CMMRD and 5 individuals with MMR-proficient LCs (controls). Using these assays, we defined experimental parameters that allowed discrimination of a series of 14 patients with CMMRD from 52 controls (training set). We then used the same parameters to assess 23 patients with clinical but not genetic features of CMMRD. RESULTS In the training set, we identified parameters, based on MSI and LC tolerance to methylation, that detected patients with CMMRD vs controls with 100% sensitivity and 100% specificity. Among 23 patients suspected of having CMMRD, 6 had MSI and LC tolerance to methylation (CMMRD highly probable), 15 had neither MSI nor LC tolerance to methylation (unlikely to have CMMRD), and 2 were considered doubtful for CMMRD based on having only 1 of the 2 features. CONCLUSION The presence of MSI and tolerance to methylation in LCs identified patients with CMMRD with 100% sensitivity and specificity. These features could be used in diagnosis of patients.
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Affiliation(s)
- Sahra Bodo
- INSERM, UMR_S 938 Centre de Recherche Saint-Antoine, Equipe Instabilité des Microsatellites et Cancer, équipe labellisée par la Ligue Nationle contre le Cancer, Paris, France; UPMC Univ Paris, Paris, France
| | - Chrystelle Colas
- INSERM, UMR_S 938 Centre de Recherche Saint-Antoine, Equipe Instabilité des Microsatellites et Cancer, équipe labellisée par la Ligue Nationle contre le Cancer, Paris, France; UPMC Univ Paris, Paris, France; AP-HP, Laboratoire d'Oncogénétique et d'Angiogénétique, GH Pitié-Salpétrière, Paris, France
| | - Olivier Buhard
- INSERM, UMR_S 938 Centre de Recherche Saint-Antoine, Equipe Instabilité des Microsatellites et Cancer, équipe labellisée par la Ligue Nationle contre le Cancer, Paris, France; UPMC Univ Paris, Paris, France
| | - Ada Collura
- INSERM, UMR_S 938 Centre de Recherche Saint-Antoine, Equipe Instabilité des Microsatellites et Cancer, équipe labellisée par la Ligue Nationle contre le Cancer, Paris, France; UPMC Univ Paris, Paris, France
| | - Julie Tinat
- Département de génétique, Hôpital universitaire, Rouen, France
| | - Noémie Lavoine
- Department of Children and Adolescents Oncology, Gustave Roussy Cancer Institute, Villejuif, France
| | - Agathe Guilloux
- INSERM, UMR_S 938 Centre de Recherche Saint-Antoine, Equipe Instabilité des Microsatellites et Cancer, équipe labellisée par la Ligue Nationle contre le Cancer, Paris, France; UPMC Univ Paris, Paris, France
| | - Alexandra Chalastanis
- INSERM, UMR_S 938 Centre de Recherche Saint-Antoine, Equipe Instabilité des Microsatellites et Cancer, équipe labellisée par la Ligue Nationle contre le Cancer, Paris, France; UPMC Univ Paris, Paris, France
| | - Philippe Lafitte
- INSERM, UMR_S 938 Centre de Recherche Saint-Antoine, Equipe Instabilité des Microsatellites et Cancer, équipe labellisée par la Ligue Nationle contre le Cancer, Paris, France; UPMC Univ Paris, Paris, France
| | - Florence Coulet
- UPMC Univ Paris, Paris, France; AP-HP, Laboratoire d'Oncogénétique et d'Angiogénétique, GH Pitié-Salpétrière, Paris, France
| | - Marie-Pierre Buisine
- Institut de Biochimie et Biologie moléculaire, Oncologie et Génétique Moléculaires, CHRU Lille, Lille, France; INSERM UMR837 et Université Lille, Lille, France
| | - Denisa Ilencikova
- 2nd Pediatric Department, Children's University Hospital, Comenius University, Bratislava, Slovakia
| | - Clara Ruiz-Ponte
- Fundación Pública Galega de Medicina Xenómica (FPGMX) SERGAS, Grupo de Medicina Xenómica, IDIS, Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERer), Santiago de Compostela, Spain
| | | | | | - Hilde Brems
- Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - Sophie Lejeune
- CHRU Lille, Service de génétique clinique, Lille, France
| | - Hélène Blanché
- CEPH, Fondation Jean Dausset, Institut de Génétique Moléculaire, Paris, France
| | - Qing Wang
- Plateforme de Génétique constitutionnelle HCL-CLB, Laboratoire de recherche translationnelle, Centre Léon Bérard, Lyon, France
| | - Olivier Caron
- Department of Medical Oncology, Gustave Roussy Cancer Institute, Villejuif, France
| | - Odile Cabaret
- Service de Génétique, Département de Biologie et Pathologie Médicales, Institut Gustave Roussy, Villejuif, France
| | - Magali Svrcek
- INSERM, UMR_S 938 Centre de Recherche Saint-Antoine, Equipe Instabilité des Microsatellites et Cancer, équipe labellisée par la Ligue Nationle contre le Cancer, Paris, France; UPMC Univ Paris, Paris, France; AP-HP, Hôpital Saint-Antoine, Service d'Anatomie et Cytologie Pathologiques, Paris, France
| | - Dominique Vidaud
- INSERM UMR745 Université Paris Descartes, Faculté des Sciences Pharmaceutiques et Biologiques, Paris, France
| | - Béatrice Parfait
- INSERM UMR745 Université Paris Descartes, Faculté des Sciences Pharmaceutiques et Biologiques, Paris, France
| | - Alain Verloes
- AP-HP, Département de Génétique and INSERM UMR 1141 PROTECT, Hôpital Robert Debré, Paris, France
| | - Ulrich J Knappe
- Department of Neurosurgery, Johannes Wesling Klinikum, Minden, Germany
| | - Florent Soubrier
- AP-HP, Département de génétique, GH Pitié-Salpêtrière, Paris, France
| | | | - Alexander Leis
- French Medical Institute for Children, Kabul, Afghanistan
| | - Jessie Auclair-Perrossier
- Plateforme de Génétique constitutionnelle HCL-CLB, Laboratoire de recherche translationnelle, Centre Léon Bérard, Lyon, France
| | | | - Jean-François Fléjou
- INSERM, UMR_S 938 Centre de Recherche Saint-Antoine, Equipe Instabilité des Microsatellites et Cancer, équipe labellisée par la Ligue Nationle contre le Cancer, Paris, France; UPMC Univ Paris, Paris, France; AP-HP, Hôpital Saint-Antoine, Service d'Anatomie et Cytologie Pathologiques, Paris, France
| | - Natacha Entz-Werle
- Pédiatrie Onco-Hématologie Pédiatrie CHRU Hautepierre UdS EA, Strasbourg, France
| | - Julie Leclerc
- Institut de Biochimie et Biologie moléculaire, Oncologie et Génétique Moléculaires, CHRU Lille, Lille, France; INSERM UMR837 et Université Lille, Lille, France
| | - David Malka
- Department of Cancer Medicine, Gustave Roussy, Villejuif, France
| | | | - Yael Goldberg
- Sharett Institute of Oncology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Anne-Marie Gerdes
- Department of Clinical Genetics, Copenhagen University Hospital Rigshospital, Copenhagen, Denmark
| | - Faten Fedhila
- Service de médecine infantile, hôpital d'enfants de Tunis, Tunis, Tunisia
| | | | - Richard Hamelin
- INSERM, UMR_S 938 Centre de Recherche Saint-Antoine, Equipe Instabilité des Microsatellites et Cancer, équipe labellisée par la Ligue Nationle contre le Cancer, Paris, France; UPMC Univ Paris, Paris, France
| | - Badre Wafaa
- Department of Hepato-Gastro-Enterology, Ibn Rochd, Hospital University Center, Casablanca, Morocco
| | | | - Franck Bourdeaut
- Department of Pediatric Oncology and INSERM U830, Institut Curie, Paris, France
| | - Eamonn Sheridan
- Department of Molecular Medicine, University of Leeds, Leeds, United Kingdom
| | - Hans Vasen
- Department of Gastroenterology and Hepatology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Laurence Brugières
- Department of Children and Adolescents Oncology, Gustave Roussy Cancer Institute, Villejuif, France
| | - Katharina Wimmer
- Division of Human Genetics, Medical University Innsbruck, Innsbruck, Austria
| | - Martine Muleris
- INSERM, UMR_S 938 Centre de Recherche Saint-Antoine, Equipe Instabilité des Microsatellites et Cancer, équipe labellisée par la Ligue Nationle contre le Cancer, Paris, France; UPMC Univ Paris, Paris, France.
| | - Alex Duval
- INSERM, UMR_S 938 Centre de Recherche Saint-Antoine, Equipe Instabilité des Microsatellites et Cancer, équipe labellisée par la Ligue Nationle contre le Cancer, Paris, France; UPMC Univ Paris, Paris, France.
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Weidmann AG, Barton JK. A monofunctional platinum complex coordinated to a rhodium metalloinsertor selectively binds mismatched DNA in the minor groove. Inorg Chem 2015; 54:9626-36. [PMID: 26397309 DOI: 10.1021/acs.inorgchem.5b01722] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
We report the synthesis and characterization of a bimetallic complex derived from a new family of potent and selective metalloinsertors containing an unusual Rh-O axial coordination. This complex incorporates a monofunctional platinum center containing only one labile site for coordination to DNA, rather than two, and coordinates DNA nonclassically through adduct formation in the minor groove. This conjugate displays bifunctional, interdependent binding of mismatched DNA via metalloinsertion at a mismatch as well as covalent platinum binding. DNA sequencing experiments revealed that the preferred site of platinum coordination is not the traditional N7-guanine site in the major groove, but rather N3-adenine in the minor groove. The complex also displays enhanced cytotoxicity in mismatch repair-deficient and mismatch repair-proficient human colorectal carcinoma cell lines compared to the chemotherapeutic cisplatin, and it triggers cell death via an apoptotic pathway, rather than the necrotic pathway induced by rhodium metalloinsertors.
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Affiliation(s)
- Alyson G Weidmann
- Division of Chemistry and Chemical Engineering, California Institute of Technology , Pasadena, California 91125, United States
| | - Jacqueline K Barton
- Division of Chemistry and Chemical Engineering, California Institute of Technology , Pasadena, California 91125, United States
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Komor AC, Barton JK. An unusual ligand coordination gives rise to a new family of rhodium metalloinsertors with improved selectivity and potency. J Am Chem Soc 2014; 136:14160-72. [PMID: 25254630 PMCID: PMC4195389 DOI: 10.1021/ja5072064] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
![]()
Rhodium
metalloinsertors are octahedral complexes that bind DNA
mismatches with high affinity and specificity and exhibit unique cell-selective
cytotoxicity, targeting mismatch repair (MMR)-deficient cells over
MMR-proficient cells. Here we describe a new generation of metalloinsertors
with enhanced biological potency and selectivity, in which the complexes
show Rh–O coordination. In particular, it has been found that
both Δ- and Λ-[Rh(chrysi)(phen)(DPE)]2+ (where
chrysi =5,6 chrysenequinone diimmine, phen =1,10-phenanthroline, and
DPE = 1,1-di(pyridine-2-yl)ethan-1-ol) bind to DNA containing a single
CC mismatch with similar affinities and without racemization. This
is in direct contrast with previous metalloinsertors and suggests
a possible different binding disposition for these complexes in the
mismatch site. We ascribe this difference to the higher pKa of the coordinated immine of the chrysi ligand in these
complexes, so that the complexes must insert into the DNA helix with
the inserting ligand in a buckled orientation; spectroscopic studies
in the presence and absence of DNA along with the crystal structure
of the complex without DNA support this assignment. Remarkably, all
members of this new family of compounds have significantly increased
potency in a range of cellular assays; indeed, all are more potent
than cisplatin and N-methyl-N′-nitro-nitrosoguanidine
(MNNG, a common DNA-alkylating chemotherapeutic agent). Moreover,
the activities of the new metalloinsertors are coupled with high levels
of selective cytotoxicity for MMR-deficient versus proficient colorectal
cancer cells.
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Affiliation(s)
- Alexis C Komor
- Division of Chemistry and Chemical Engineering, California Institute of Technology , Pasadena California 91125, United States
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Abstract
Classical chemotherapeutics, such as cisplatin and its analogues, have been highly successful in the clinic, yet improvements can certainly be made, given the significant side effects associated with the killing of healthy cells. Recent advances in the field of chemotherapy include the development of targeted anticancer agents, compounds that are directed towards a specific biomarker of cancer, with the hopes that such targeted therapies might have reduced side effects given their greater selectivity. Here we discuss several transition metal complexes that are tailored towards various biomolecules associated with cancer. Most notably, the success of rhodium metalloinsertors, which specifically bind to nucleic acid base mismatches in DNA, highlight the enormous potential of this exciting new strategy.
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Affiliation(s)
- Alyson G Weidmann
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Alexis C Komor
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Jacqueline K Barton
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125
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Nagel ZD, Chaim IA, Samson LD. Inter-individual variation in DNA repair capacity: a need for multi-pathway functional assays to promote translational DNA repair research. DNA Repair (Amst) 2014; 19:199-213. [PMID: 24780560 DOI: 10.1016/j.dnarep.2014.03.009] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Why does a constant barrage of DNA damage lead to disease in some individuals, while others remain healthy? This article surveys current work addressing the implications of inter-individual variation in DNA repair capacity for human health, and discusses the status of DNA repair assays as potential clinical tools for personalized prevention or treatment of disease. In particular, we highlight research showing that there are significant inter-individual variations in DNA repair capacity (DRC), and that measuring these differences provides important biological insight regarding disease susceptibility and cancer treatment efficacy. We emphasize work showing that it is important to measure repair capacity in multiple pathways, and that functional assays are required to fill a gap left by genome wide association studies, global gene expression and proteomics. Finally, we discuss research that will be needed to overcome barriers that currently limit the use of DNA repair assays in the clinic.
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Affiliation(s)
- Zachary D Nagel
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Isaac A Chaim
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Leona D Samson
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; The David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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Golden J, Motea E, Zhang X, Choi JS, Feng Y, Xu Y, Lee I, Berdis AJ. Development and characterization of a non-natural nucleoside that displays anticancer activity against solid tumors. ACS Chem Biol 2013; 8:2452-65. [PMID: 23992753 DOI: 10.1021/cb400350h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Nucleoside analogs are an important class of anticancer agent that historically show better efficacy against hematological cancers versus solid tumors. This report describes the development and characterization of a new class of nucleoside analog that displays anticancer effects against both hematological and adherent cancer cell lines. These new analogs lack canonical hydrogen-bonding groups yet are effective nucleotide substrates for several high-fidelity DNA polymerases. Permutations in the position of the non-hydrogen-bonding functional group greatly influence the kinetic behavior of these nucleosides. One particular analog designated 4-nitroindolyl-2'-deoxynucleoside triphosphate (4-NITP) is unique as it is incorporated opposite C and T with high catalytic efficiencies. In addition, this analog functions as a nonobligate chain terminator of DNA synthesis, since it is poorly elongated. Consistent with this mechanism, the corresponding nucleoside, 4-nitroindolyl-2'-deoxynucleoside (4-NIdR), produces antiproliferative effects against leukemia cells. 4-NIdR also produces cytostatic and cytotoxic effects against several adherent cancer cell lines, especially those that are deficient in mismatch repair and p53. Cell death in this case appears to occur via mitotic catastrophe, a specialized form of apoptosis. Mass spectroscopy experiments performed on nucleic acid isolated from cells treated with 4-NIdR validate that the non-natural nucleoside is stably incorporated into DNA. Xenograft mouse studies demonstrate that administration of 4-NIdR delays tumor growth without producing adverse side effects such as anemia and thrombocytopenia. Collectively, the results of in vitro, cell-based, and animal studies provide evidence for the development of a novel nucleoside analog that shows enhanced effectiveness against solid tumors.
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Affiliation(s)
- Jackelyn Golden
- Departments of Pharmacology and ‡Chemistry, Case Western Reserve University , 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
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Regulation of MLH1 mRNA and protein expression by promoter methylation in primary colorectal cancer: a descriptive and prognostic cancer marker study. Cell Oncol (Dordr) 2013; 36:411-9. [PMID: 24027018 DOI: 10.1007/s13402-013-0148-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/27/2013] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND In colorectal cancer MLH1 deficiency causes microsatellite instability, which is relevant for the patient's prognosis and treatment, and its putative heredity. Dysfunction of MLH1 is caused by sporadic gene promoter hypermethylation or by hereditary mutations as seen in Lynch Syndrome. The aim of this study was to determine in detail how DNA methylation regulates MLH1 expression and impacts clinical management. METHODS Colorectal cancer samples were collected from 210 patients. The laboratory methods used to study these samples included methylation specific multiplex ligation-dependent probe amplification (MS-MLPA), real-time quantitative PCR (qPCR), and immunohistochemistry (IHC). RESULTS We found that the MLH1 mRNA and protein expression levels were highly related. MS-MLPA was successful in tumors from 195 patients. In these tumors, hypermethylation was observed in promoter regions A (n = 57), B (n = 30), C (n = 28), and D (n = 47), and in intron 1 (n = 25). The promoter region C and intron 1 methylation levels were found to be excellently suited for discriminating between low and high gene expression levels, whereas those of promoter regions A, B and D were less specific. Hypermethylation in any region (n = 77) served as an independent prognostic factor (hazard ratio 0.56, 95 % confidence interval 0.36-0.89, p = 0.01). CONCLUSIONS MLH1 inactivation through hypermethylation was found to be related to improved survival. Hypermethylation in promoter region C and intron 1 served as the most specific markers for this inactivation.
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Abstract
The discovery of cisplatin as a therapeutic agent stimulated a new era in the application of transition metal complexes for therapeutic design. Here we describe recent results on a variety of transition metal complexes targeted to DNA to illustrate many of the issues involved in new therapeutic design. We describe first structural studies of complexes bound covalently and non-covalently to DNA to identify potential lesions within the cell. We then review the biological fates of these complexes, illustrating the key elements in obtaining potent activity, the importance of uptake and subcellular localization of the complexes, as well as the techniques used to delineate these characteristics. Genomic DNA provides a challenging but valuable target for new transition metal-based therapeutics.
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Affiliation(s)
| | - Jacqueline K. Barton
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena CA 91125, USA. Fax: 626-577-4976; Tel: 626-395-6075;
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Komor AC, Schneider CJ, Weidmann AG, Barton JK. Cell-selective biological activity of rhodium metalloinsertors correlates with subcellular localization. J Am Chem Soc 2012; 134:19223-33. [PMID: 23137296 PMCID: PMC3740518 DOI: 10.1021/ja3090687] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Deficiencies in the mismatch repair (MMR) pathway are associated with several types of cancers, as well as resistance to commonly used chemotherapeutics. Rhodium metalloinsertors have been found to bind DNA mismatches with high affinity and specificity in vitro, and also exhibit cell-selective cytotoxicity, targeting MMR-deficient cells over MMR-proficient cells. Ten distinct metalloinsertors with varying lipophilicities have been synthesized and their mismatch binding affinities and biological activities determined. Although DNA photocleavage experiments demonstrate that their binding affinities are quite similar, their cell-selective antiproliferative and cytotoxic activities vary significantly. Inductively coupled plasma mass spectrometry (ICP-MS) experiments have uncovered a relationship between the subcellular distribution of these metalloinsertors and their biological activities. Specifically, we find that all of our metalloinsertors localize in the nucleus at sufficient concentrations for binding to DNA mismatches. However, the metalloinsertors with high rhodium localization in the mitochondria show toxicity that is not selective for MMR-deficient cells, whereas metalloinsertors with less mitochondrial rhodium show activity that is highly selective for MMR-deficient versus proficient cells. This work supports the notion that specific targeting of the metalloinsertors to nuclear DNA gives rise to their cell-selective cytotoxic and antiproliferative activities. The selectivity in cellular targeting depends upon binding to mismatches in genomic DNA.
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Affiliation(s)
- Alexis C. Komor
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena CA 91125
| | - Curtis J. Schneider
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena CA 91125
| | - Alyson G. Weidmann
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena CA 91125
| | - Jacqueline K. Barton
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena CA 91125
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Carethers JM. Proteomics, genomics, and molecular biology in the personalized treatment of colorectal cancer. J Gastrointest Surg 2012; 16:1648-50. [PMID: 22760966 PMCID: PMC3424282 DOI: 10.1007/s11605-012-1942-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Accepted: 06/15/2012] [Indexed: 01/31/2023]
Abstract
Colorectal cancer develops and progresses from genetic and genomic changes that occur within and transforms the growth behavior of a normal colonic cell. Molecular tools have advanced enough to allow the scientific community to probe deeper into risk alleles within a population as well as into individual patient genetic data that can ascribe such a risk. Detected genetic and genomic changes from colorectal cancer can help determine a patient's prognosis, predict response to chemotherapy, and determine the approach to care with biological therapies. Utilizing stool, blood/plasma, and tumor tissue to obtain genetic, genomic, and pharmacokinetic information contribute to a person's profile to direct specific cancer care.
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Affiliation(s)
- John M. Carethers
- Division of Gastroenterology, Department of Internal Medicine, University of Michigan, 3901 Taubman Center, SPC 5368, 1500 E. Medical Center Drive, Ann Arbor, MI 48109-5368, USA
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Odajima C, Nakamura T, Nakai M, Yamazaki K, Hattori S, Murakami N, Honda G, Yamamoto A, Kawaguchi S, Sasaki YF. How Is the Formation of Comet Tails Supported by the Incision Step of Nucleotide Excision Repair? Genes Environ 2012. [DOI: 10.3123/jemsge.34.101] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Ernst RJ, Komor AC, Barton JK. Selective cytotoxicity of rhodium metalloinsertors in mismatch repair-deficient cells. Biochemistry 2011; 50:10919-28. [PMID: 22103240 DOI: 10.1021/bi2015822] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Mismatches in DNA occur naturally during replication and as a result of endogenous DNA damaging agents, but the mismatch repair (MMR) pathway acts to correct mismatches before subsequent rounds of replication. Rhodium metalloinsertors bind to DNA mismatches with high affinity and specificity and represent a promising strategy to target mismatches in cells. Here we examine the biological fate of rhodium metalloinsertors bearing dipyridylamine ancillary ligands in cells deficient in MMR versus those that are MMR-proficient. These complexes are shown to exhibit accelerated cellular uptake which permits the observation of various cellular responses, including disruption of the cell cycle, monitored by flow cytometry assays, and induction of necrosis, monitored by dye exclusion and caspase inhibition assays, that occur preferentially in the MMR-deficient cell line. These cellular responses provide insight into the mechanisms underlying the selective activity of this novel class of targeted anticancer agents.
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Affiliation(s)
- Russell J Ernst
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
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Jascur T, Fotedar R, Greene S, Hotchkiss E, Boland CR. N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) triggers MSH2 and Cdt2 protein-dependent degradation of the cell cycle and mismatch repair (MMR) inhibitor protein p21Waf1/Cip1. J Biol Chem 2011; 286:29531-9. [PMID: 21725088 DOI: 10.1074/jbc.m111.221341] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
p21(Waf1/Cip1) protein levels respond to DNA damage; p21 is induced after ionizing radiation, but degraded after UV. p21 degradation after UV is necessary for optimal DNA repair, presumably because p21 inhibits nucleotide excision repair by blocking proliferating cell nuclear antigen (PCNA). Because p21 also inhibits DNA mismatch repair (MMR), we investigated how p21 levels respond to DNA alkylation by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), which triggers the MMR system. We show that MNNG caused rapid degradation of p21, and this involved the ubiquitin ligase Cdt2 and the proteasome. p21 degradation further required MSH2 but not MLH1. p21 mutants that cannot bind PCNA or cannot be ubiquitinated were resistant to MNNG. MNNG induced the formation of PCNA complexes with MSH6 and Cdt2. Finally, when p21 degradation was blocked, MNNG treatment resulted in reduced recruitment of MMR proteins to chromatin. This study describes a novel pathway that removes p21 to allow cells to efficiently activate the MMR system.
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Affiliation(s)
- Thomas Jascur
- Baylor Research Institute and Sammons Cancer Center, Baylor University Medical Center, Dallas, Texas 75246, USA
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Yamamoto A, Sakamoto Y, Masumura K, Honma M, Nohmi T. Involvement of mismatch repair proteins in adaptive responses induced by N-methyl-N'-nitro-N-nitrosoguanidine against γ-induced genotoxicity in human cells. Mutat Res 2011; 713:56-63. [PMID: 21704047 DOI: 10.1016/j.mrfmmm.2011.05.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2011] [Revised: 05/20/2011] [Accepted: 05/23/2011] [Indexed: 10/18/2022]
Abstract
As humans are exposed to a variety of chemical agents as well as radiation, health effects of radiation should be evaluated in combination with chemicals. To explore combined genotoxic effects of radiation and chemicals, we examined modulating effects of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), a direct-acting methylating agent, against genotoxicity of γ-radiation. Human lymphoblastoid TK6 cells and its mismatch-deficient derivative, i.e., MT1 cells, were treated with MNNG for 24h before they were exposed to γ-irradiation at a dose of 1.0 Gy, and the resulting genotoxicity was examined. In TK6 cells, the pretreatments with MNNG at low doses suppressed frequencies of the thymidine kinase (TK) gene mutation and micronucleus (MN) formation induced by γ-irradiation and thus the dose responses of TK and MN assays were U-shaped along with the pretreatment doses of MNNG. In contrast, the genotoxic effects of MNNG and γ-irradiation were additive in MT1 cells and the frequencies of TK mutations and MN induction increased along with the doses of MNNG. Apoptosis induced by γ-radiation was suppressed by the pretreatments in TK6 cells, but not in MT1 cells. The expression of p53 was induced and cell cycle was delayed at G2/M phase in TK6, but not in MT1 cells, by the treatments with MNNG. These results suggest that pretreatments of MNNG at low doses suppress genotoxicity of γ-radiation in human cells and also that mismatch repair proteins are involved in the apparent adaptive responses.
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Affiliation(s)
- Ayumi Yamamoto
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
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Pino MS, Chung DC. Microsatellite instability in the management of colorectal cancer. Expert Rev Gastroenterol Hepatol 2011; 5:385-99. [PMID: 21651356 DOI: 10.1586/egh.11.25] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Microsatellite instability (MSI) is a form of genetic instability caused by alterations in the DNA mismatch repair system. Approximately 15% of colorectal cancers display MSI due to a germline mutation in one of the mismatch repair genes (MLH1, MSH2, MSH6 and PMS2) or to epigenetic silencing of MLH1. Colorectal cancers with MSI have distinctive features, including a tendency to arise in the proximal colon, poor differentiation, lymphocytic infiltration and mucinous or signet-ring histology. Patients with MSI tumors appear to have a better prognosis than those with microsatellite stable tumors, but curiously the responses to 5-fluorouracil-based chemotherapy regimens are poorer with MSI tumors. Preliminary data suggest possible advantages of irinotecan-based regimens, but these findings need validation in well-designed clinical trials.
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Affiliation(s)
- Maria S Pino
- Gastrointestinal Unit, Massachusetts General Hospital, 50 Blossom Street, Boston, MA 02114, USA
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35
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Chung H, Chaudhry J, Lopez CG, Carethers JM. Cyclin E and histone H3 levels are regulated by 5-fluorouracil in a DNA mismatch repair-dependent manner. Cancer Biol Ther 2010; 10:1147-56. [PMID: 20930505 DOI: 10.4161/cbt.10.11.13447] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Several studies indicate that the DNA mismatch repair (MMR) system may trigger cytotoxicity upon 5-fluorouracil (5-FU) recognition, but signaling pathways regulated by MMR in response to 5-FU are unknown. We hypothesize that recognition of 5-FU in DNA by MMR proteins trigger specific signaling cascades that results in slowing of the cell cycle and cell death. Whole human genome cDNA microarrays were used to examine relative signaling responses induced in MMR-proficient cells after 5-FU (5 μM) treatment for 24 hours. Analysis revealed 43 pathways differentially affected by 5-FU compared to control (P 1.4-fold) and downregulated cdc25C, cyclins B1 and B2, histone H2A, H2B, and H3 (< -1.4-fold) over control. Cell cycle analysis revealed a G1/S arrest by 5-FU that was congruent with increased cyclin E and decreased cdc25C protein expression. Importantly, with knockdown of hMLH1 and hMSH2, we observed that decreased histone H3 expression by 5-FU was dependent on hMLH1. Additionally, 5-FU treatment dramatically decreased levels of several histone H3 modifications. Our data suggest that 5-FU induces a G1/S arrest by regulating cyclin E and cdc25C expression, and MMR recognition of 5-FU in DNA may modulate cyclin E to affect the cell cycle. Furthermore, MMR recognition of 5-FU reduces histone H3 levels that could be related to DNA access by proteins and/or cell death during the G1/S phase of the cell cycle.
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Affiliation(s)
- Heekyung Chung
- Department of Medicine, University of California, San Diego, CA, USA
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36
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Martin LM, Marples B, Coffey M, Lawler M, Lynch TH, Hollywood D, Marignol L. DNA mismatch repair and the DNA damage response to ionizing radiation: Making sense of apparently conflicting data. Cancer Treat Rev 2010; 36:518-27. [PMID: 20413225 DOI: 10.1016/j.ctrv.2010.03.008] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2010] [Revised: 03/12/2010] [Accepted: 03/21/2010] [Indexed: 10/19/2022]
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Hall G, Clarkson A, Shi A, Langford E, Leung H, Eckstein RP, Gill AJ. Immunohistochemistry for PMS2 and MSH6 alone can replace a four antibody panel for mismatch repair deficiency screening in colorectal adenocarcinoma. Pathology 2010; 42:409-13. [PMID: 20632815 DOI: 10.3109/00313025.2010.493871] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AIMS Currently, testing for mismatch repair deficiency in colorectal cancers is initiated by performing immunohistochemistry with four antibodies (MLH1, PMS2, MSH2 and MSH6). If any one of these stains is negative the tumour is considered microsatellite unstable and, if clinical circumstances warrant it, the patient is offered genetic testing for Lynch's syndrome. Due to the binding properties of the mismatch repair heterodimer complexes, gene mutation and loss of MLH1 and MSH2 invariably result in the degradation of PMS2 and MSH6, respectively, but the converse is not true. We propose that staining for PMS2 and MSH6 alone will be sufficient to detect all cases of mismatch repair deficiency and should replace routine screening with all four antibodies. METHODS The electronic database of the department of Anatomical Pathology, Royal North Shore Hospital, Sydney, Australia, was searched for all colorectal carcinomas on which a four panel immunohistochemical microsatellite instability screen was performed. An audit of the slides for concordant loss of MLH1-PMS2 and MSH2-MSH6 was then undertaken. Unusual or discordant cases were reviewed and, in some cases, re-stained to confirm the staining pattern. RESULTS Of 344 cases of colorectal cancer which underwent four antibody immunohistochemistry, 104 displayed loss of at least one mismatch repair protein. Of these, 100 showed concordant mismatch repair loss (i.e., loss of MLH1 and PMS2 or loss of MSH2 and MSH6). The four discordant cases comprised two single negative cases (1 MSH6 negative/MSH2 positive case, 1 PMS2 negative/MLH1 positive) and two triple negative (both MLH1/PMS2/MSH6 negative). The microsatellite instability (MSI) group showed a relatively high median age (69.3 years) due to the departmental policy of testing all cases with possible MSI morphology regardless of age. CONCLUSIONS The sensitivity and specificity of a two panel test comprised of PMS2 and MSH6, compared to a four panel test, is 100%. No false negatives or positives were identified. We conclude that the two panel test should replace a four panel protocol for immunohistochemical screening for mismatch repair deficiency.
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Affiliation(s)
- Geoffrey Hall
- Institute of Clinical Pathology and Medical Research, Department of Anatomical Pathology, Westmead Public Hospital, Westmead, Australia
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Boland CR, Goel A. Microsatellite instability in colorectal cancer. Gastroenterology 2010; 138:2073-2087.e3. [PMID: 20420947 PMCID: PMC3037515 DOI: 10.1053/j.gastro.2009.12.064] [Citation(s) in RCA: 1407] [Impact Index Per Article: 100.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2009] [Revised: 12/23/2009] [Accepted: 12/30/2009] [Indexed: 02/07/2023]
Abstract
Microsatellite instability (MSI) is a hypermutable phenotype caused by the loss of DNA mismatch repair activity. MSI is detected in about 15% of all colorectal cancers; 3% are of these are associated with Lynch syndrome and the other 12% are caused by sporadic, acquired hypermethylation of the promoter of the MLH1 gene, which occurs in tumors with the CpG island methylator phenotype. Colorectal tumors with MSI have distinctive features, including a tendency to arise in the proximal colon, lymphocytic infiltrate, and a poorly differentiated, mucinous or signet ring appearance. They have a slightly better prognosis than colorectal tumors without MSI and do not have the same response to chemotherapeutics. Discovery of MSI in colorectal tumors has increased awareness of the diversity of colorectal cancers and implications for specialized management of patients.
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BOLAND CRICHARD. A knockout for Lynch syndrome. Gastroenterology 2010; 138:820-2. [PMID: 20102757 PMCID: PMC2846619 DOI: 10.1053/j.gastro.2010.01.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Affiliation(s)
- C. RICHARD BOLAND
- GI Cancer Research Laboratory, Division of Gastroenterology, Department of Internal Medicine, Sammons Cancer Center and, Baylor Research Institute, Baylor University Medical Center, Dallas, Texas
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Abstract
Lynch syndrome (LS) is an autosomal dominant cancer predisposition syndrome attributable to deleterious germline mutations in mismatch repair (MMR) genes. The syndrome is typified by early-onset, frequently right-sided colorectal cancers (CRCs) with characteristic histologic features and tendency for multiplicity and an increased risk for extracolonic tumors at particular sites; it accounts for 1% to 5% of CRC. Deficient mismatch repair (dMMR) function manifests as immunohistochemically detectable absence of one or more MMR proteins and microsatellite instability (MSI). Approximately 15% of sporadic, noninherited CRC are characterized by high-level MSI, nearly always owing to transcriptional silencing of MLH1; these sporadic and LS cases exhibit considerable phenotypic overlap. Identification of CRC with dMMR is desirable to identify LS and because MSI status is prognostic and potentially predictive. This review will discuss the history of LS, the principles of MMR and MSI, the clinicopathologic features of LS-associated and sporadic high-level MSI CRC, the fundamentals of clinical testing for dMMR CRC, and the results of the Columbus-area Lynch syndrome study. We conclude with our approach to population-based LS screening based on institutional experience with nearly 2000 cases.
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Kumari R, Singh KP, DuMond JW. Simulated microgravity decreases DNA repair capacity and induces DNA damage in human lymphocytes. J Cell Biochem 2009; 107:723-31. [DOI: 10.1002/jcb.22171] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Lynch HT, Lynch PM, Lanspa SJ, Snyder CL, Lynch JF, Boland CR. Review of the Lynch syndrome: history, molecular genetics, screening, differential diagnosis, and medicolegal ramifications. Clin Genet 2009; 76:1-18. [PMID: 19659756 PMCID: PMC2846640 DOI: 10.1111/j.1399-0004.2009.01230.x] [Citation(s) in RCA: 562] [Impact Index Per Article: 37.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
More than one million patients will manifest colorectal cancer (CRC) this year of which, conservatively, approximately 3% (approximately 30,700 cases) will have Lynch syndrome (LS), the most common hereditary CRC predisposing syndrome. Each case belongs to a family with clinical needs that require genetic counseling, DNA testing for mismatch repair genes (most frequently MLH1 or MSH2) and screening for CRC. Colonoscopy is mandated, given CRC's proximal occurrence (70-80% proximal to the splenic flexure). Due to its early age of onset (average 45 years of age), colonoscopy needs to start by age 25, and because of its accelerated carcinogenesis, it should be repeated every 1 to 2 years through age 40 and then annually thereafter. Should CRC occur, subtotal colectomy may be necessary, given the marked frequency of synchronous and metachronous CRC. Because 40-60% of female patients will manifest endometrial cancer, tailored management is essential. Additional extracolonic cancers include ovary, stomach, small bowel, pancreas, hepatobiliary tract, upper uroepithelial tract, brain (Turcot variant) and sebaceous adenomas/carcinomas (Muir-Torre variant). LS explains only 10-25% of familial CRC.
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Affiliation(s)
- H T Lynch
- Department of Preventive Medicine, Creighton University School of Medicine, Omaha, NE 68178, USA.
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Ernst RJ, Song H, Barton JK. DNA mismatch binding and antiproliferative activity of rhodium metalloinsertors. J Am Chem Soc 2009; 131:2359-66. [PMID: 19175313 DOI: 10.1021/ja8081044] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Deficiencies in mismatch repair (MMR) are associated with carcinogenesis. Rhodium metalloinsertors bind to DNA base mismatches with high specificity and inhibit cellular proliferation preferentially in MMR-deficient cells versus MMR-proficient cells. A family of chrysenequinone diimine complexes of rhodium with varying ancillary ligands that serve as DNA metalloinsertors has been synthesized, and both DNA mismatch binding affinities and antiproliferative activities against the human colorectal carcinoma cell lines HCT116N and HCT116O, an isogenic model system for MMR deficiency, have been determined. DNA photocleavage experiments reveal that all complexes bind to the mismatch sites with high specificities; DNA binding affinities to oligonucleotides containing single base CA and CC mismatches, obtained through photocleavage titration or competition, vary from 10(4) to 10(8) M(-1) for the series of complexes. Significantly, binding affinities are found to be inversely related to ancillary ligand size and directly related to differential inhibition of the HCT116 cell lines. The observed trend in binding affinity is consistent with the metalloinsertion mode where the complex binds from the minor groove with ejection of mismatched base pairs. The correlation between binding affinity and targeting of the MMR-deficient cell line suggests that rhodium metalloinsertors exert their selective biological effects on MMR-deficient cells through mismatch binding in vivo.
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Affiliation(s)
- Russell J Ernst
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
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Lynch HT, Boland CR, Gong G, Shaw TG, Lynch PM, Fodde R, Lynch JF, de la Chapelle A. Phenotypic and genotypic heterogeneity in the Lynch syndrome: diagnostic, surveillance and management implications. Eur J Hum Genet 2009; 14:390-402. [PMID: 16479259 DOI: 10.1038/sj.ejhg.5201584] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Lynch syndrome is the most common form of hereditary colorectal cancer (CRC). This review covers the cardinal features of Lynch syndrome with particular emphasis upon its diagnostic criteria, molecular genetics, natural history, genetic counseling, surveillance and management. Considerable attention has been given to the etiologic role of mismatch repair (MMR) genes as well as low penetrance alleles and modifier genes. The American founder mutation, a deletion of exons 1-6 of MSH2, is discussed in some detail, owing to its high frequency in the US (19 000-30 000 carriers). Genetic counseling is essential prior to patients' undergoing DNA testing and again when receiving their test results. Families with a lower incidence of CRC and extracolonic cancers, in the face of being positive for Amsterdam I criteria but who do not have MMR deficiency by tumor testing, are probably not Lynch syndrome, and thereby should preferably be designated as familial CRC of undetermined type. Patients who are either noncompliant or poorly compliant with colonoscopy, and who are MMR mutation positive, may be candidates for prophylactic colectomy, while MMR mutation-positive women who are noncompliant with gynecologic surveillance may be candidates for prophylactic hysterectomy and bilateral salpingo-oophorectomy.
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Affiliation(s)
- Henry T Lynch
- Department of Preventive Medicine, Creighton University School of Medicine, 2500 California Plaza, Omaha, NE 68178, USA.
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Abstract
Suicide gene therapy with herpes simplex virus thymidine kinase and ganciclovir is notable for producing multi-log cytotoxicity in a unique pattern of delayed cytotoxicity in S-phase. Because hydroxyurea, a ribonucleotide reductase inhibitor that activates mismatch repair, can increase sensitivity to ganciclovir, we evaluated the role of MLH1, an essential mismatch repair protein, in ganciclovir cytotoxicity. Using HCT116TK (HSV-TK-expressing) colon carcinoma cells that express or lack MLH1, cell survival studies demonstrated greater ganciclovir sensitivity in the MLH1 deficient cells, primarily at high concentrations. This could not be explained by differences in ganciclovir metabolism, as the less sensitive MLH1-expresssing cells accumulated more ganciclovir triphosphate and incorporated more of the analog into DNA. SiRNA suppression of MLH1 in U251 glioblastoma or SW480 colon carcinoma cells also enhanced sensitivity to high concentrations of ganciclovir. Studies in a panel of yeast deletion mutants confirmed the results with MLH1, and further suggested a role for homologous recombination repair and several cell cycle checkpoint proteins in ganciclovir cytotoxicity. These data suggest that MLH1 can prevent cytotoxicity with ganciclovir. Targeting mismatch repair-deficient tumors may increase efficacy of this suicide gene therapy approach to cancer treatment.
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46
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Lynch HT, Casey MJ, Snyder CL, Bewtra C, Lynch JF, Butts M, Godwin AK. Hereditary ovarian carcinoma: heterogeneity, molecular genetics, pathology, and management. Mol Oncol 2009; 3:97-137. [PMID: 19383374 DOI: 10.1016/j.molonc.2009.02.004] [Citation(s) in RCA: 135] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2009] [Revised: 02/03/2009] [Accepted: 02/06/2009] [Indexed: 12/18/2022] Open
Abstract
Hereditary ovarian cancer accounts for at least 5% of the estimated 22,000 new cases of this disease during 2009. During this same time, over 15,000 will die from malignancy ascribed to ovarian origin. The bulk of these hereditary cases fits the hereditary breast-ovarian cancer syndrome, while virtually all of the remainder will be consonant with the Lynch syndrome, disorders which are autosomal dominantly inherited. Advances in molecular genetics have led to the identification of BRCA1 and BRCA2 gene mutations which predispose to the hereditary breast-ovarian cancer syndrome, and mutations in mismatch repair genes, the most common of which are MSH2 and MLH1, which predispose to Lynch syndrome. These discoveries enable relatively certain diagnosis, limited only by their variable penetrance, so that identification of mutation carriers through a comprehensive cancer family history might be possible. This paper reviews the subject of hereditary ovarian cancer, with particular attention to its molecular genetic basis, its pathology, and its phenotypic/genotypic heterogeneity.
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Affiliation(s)
- Henry T Lynch
- Department of Preventive Medicine and Public Health, Creighton University School of Medicine, 2500 California Plaza, Omaha, NE 68178, USA.
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Genomic and epigenetic instability in colorectal cancer pathogenesis. Gastroenterology 2008; 135:1079-99. [PMID: 18773902 PMCID: PMC2866182 DOI: 10.1053/j.gastro.2008.07.076] [Citation(s) in RCA: 680] [Impact Index Per Article: 42.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2008] [Revised: 07/07/2008] [Accepted: 07/28/2008] [Indexed: 12/11/2022]
Abstract
Colorectal cancer arises as a consequence of the accumulation of genetic alterations (gene mutations, gene amplification, and so on) and epigenetic alterations (aberrant DNA methylation, chromatin modifications, and so on) that transform colonic epithelial cells into colon adenocarcinoma cells. The loss of genomic stability and resulting gene alterations are key molecular pathogenic steps that occur early in tumorigenesis; they permit the acquisition of a sufficient number of alterations in tumor suppressor genes and oncogenes that transform cells and promote tumor progression. Two predominant forms of genomic instability that have been identified in colon cancer are microsatellite instability and chromosome instability. Substantial progress has been made to identify causes of chromosomal instability in colorectal cells and to determine the effects of the different forms of genomic instability on the biological and clinical behavior of colon tumors. In addition to genomic instability, epigenetic instability results in the aberrant methylation of tumor suppressor genes. Determining the causes and roles of genomic and epigenomic instability in colon tumor formation has the potential to yield more effective prevention strategies and therapeutics for patients with colorectal cancer.
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48
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Abstract
Colorectal cancer is a prevalent disease in Western countries. While prevention through screening is the best approach to combat the development of colorectal cancer through the removal of precursor adenomas, many patients present with advanced disease that will require surgery and systemic therapy to improve survival. With reference to systemic therapy, the median survival of patients with metastatic colorectal cancer (those with tumor spread to lymph nodes or distant sites) has improved over the past three decades due to the introduction of 5-fluorouracil (5-FU), its subsequent biomodulation, and the addition other chemotherapeutic agents. There is now evidence that the biology of the colorectal tumor, in addition to the stage of colorectal cancer, may predict response to 5-FU-based therapy. More recently, systemic biological therapies that target signaling processes for tumor growth, such as epidermal growth factor receptor, and vascular endothelial growth factor, are also effective in improving patient survival with metastatic colorectal cancer. The use of a combination of systemic therapies that include chemotherapy and biologic therapy should continue to increase patient survival with metastatic colorectal cancer through appropriately designed clinical trials. Treatments based on the biology of the colorectal tumor also need to be examined through clinical trials.
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Affiliation(s)
- John M Carethers
- Division of Gastroenterology UC303, MC 0063 University of California San Diego 9500 Gilman Drive, La Jolla CA 92093-0063, USA
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Campregher C, Luciani MG, Gasche C. Activated neutrophils induce an hMSH2-dependent G2/M checkpoint arrest and replication errors at a (CA)13-repeat in colon epithelial cells. Gut 2008; 57:780-7. [PMID: 18272544 PMCID: PMC2564829 DOI: 10.1136/gut.2007.141556] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Revised: 01/08/2008] [Accepted: 02/02/2008] [Indexed: 12/19/2022]
Abstract
OBJECTIVE Chronic inflammation in ulcerative colitis is associated with increased risk for colorectal cancer. Its molecular pathway of cancer development is poorly understood. We investigated the role of neutrophil-derived cellular stress in an in vitro model of neutrophils as effectors and colon epithelial cells as targets, and tested for changes in cell cycle distribution and the appearance of replication errors. DESIGN Colon epithelial cells with different mismatch repair phenotypes were co-cultured with activated neutrophils. Target cells were analysed for cell cycle distribution and replication errors by flow cytometry. Changes in nuclear and DNA-bound levels of mismatch repair- and checkpoint-related proteins were analysed by western blotting. RESULTS Activated neutrophils cause an accumulation of target cells in G2/M, consistent with the installation of a DNA-damage checkpoint. Cells that do not express hMSH2, p53 or p21(waf1/cip1) failed to undergo the G2/M arrest. Phosphorylation of p53 at site Ser15 and Chk1 at Ser317, as well as accumulation of p21(waf1/cip1), was observed within 8-24 h. Superoxide dismutase and catalase were unable to overcome this G2/M arrest, possibly indicating that neutrophil products other than superoxide or H(2)O(2) are involved in this cellular response. Finally, exposure to activated neutrophils increased the number of replication errors. CONCLUSIONS By using an in vitro co-culture model that mimics intestinal inflammation in ulcerative colitis, we provide molecular evidence for an hMSH2-dependent G2/M checkpoint arrest and for the presence of replication errors.
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Affiliation(s)
- C Campregher
- AKH Wien, Division of Gastroenterology and Hepatology, Währinger Gürtel 18, A-1090 Vienna, Austria
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Boland CR, Koi M, Chang DK, Carethers JM. The biochemical basis of microsatellite instability and abnormal immunohistochemistry and clinical behavior in Lynch syndrome: from bench to bedside. Fam Cancer 2007; 7:41-52. [PMID: 17636426 PMCID: PMC2847875 DOI: 10.1007/s10689-007-9145-9] [Citation(s) in RCA: 129] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2007] [Accepted: 05/14/2007] [Indexed: 02/07/2023]
Abstract
Lynch syndrome is an inherited disease caused by a germline mutation in one of four DNA mismatch repair (MMR) genes. The clinical manifestations can be somewhat variable depending upon which gene is involved, and where the mutation occurs. Moreover, the approach to the diagnosis of Lynch syndrome is becoming more complex as more is learned about the disease, and one needs to understand how the DNA MMR proteins function, and what makes them malfunction, to have an optimal appreciation of how to interpret diagnostic studies such as microsatellite instability and immunohistochemistry of the DNA MMR proteins. Finally, an understanding of the role of the DNA MMR system in regulation of the cell cycle and the response to DNA damage helps illuminate the differences in natural history and response to chemotherapeutic agents seen in Lynch syndrome.
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Affiliation(s)
- C. Richard Boland
- Department of Internal Medicine and Sammons Cancer Center, Baylor University Medical Center (250 Hoblitzelle), 3500 Gaston Avenue, Dallas, TX 75246, USA
| | - Minoru Koi
- Department of Internal Medicine and Sammons Cancer Center, Baylor University Medical Center (250 Hoblitzelle), 3500 Gaston Avenue, Dallas, TX 75246, USA
| | - Dong K. Chang
- Sungkyunkwan University School of Medicine, Samsung Medical Center, Seoul, Korea
| | - John M. Carethers
- Department of Medicine, University of California, San Diego, CA, USA
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