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Mull BB, Livingston JA, Patel N, Bui T, Hunt KK, Keyomarsi K. Specific, reversible G1 arrest by UCN-01 in vivo provides cytostatic protection of normal cells against cytotoxic chemotherapy in breast cancer. Br J Cancer 2020; 122:812-822. [PMID: 31942030 PMCID: PMC7078276 DOI: 10.1038/s41416-019-0707-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 11/19/2019] [Accepted: 12/11/2019] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND Low-dose UCN-01 mediates G1 arrest in normal proliferating cell lines with an intact G1 to S transition but not tumour cells with a deregulated G1 to S checkpoint. Here we hypothesised that UCN-01 is effective in mediating a selective, reversible G1 arrest of normal proliferating cells, resulting in decreased chemotoxicity, improved tolerance and enhanced chemotherapeutic efficacy in vivo in both non-tumour-bearing mice and in breast cancer cell line xenograft models. METHODS Murine small bowel epithelium was used to examine the kinetics and mechanism of low-dose UCN-01-mediated arrest of normal proliferating cells and if it can protect tumour-bearing mice (MDA-MB-468 xenografts) against the toxic effects of chemotherapy (5-fluorouricil (5-FU)) allowing for its full therapeutic activity. RESULTS UCN-01 causes significant, reversible arrest of normal gut epithelial cells at 24 h; this arrest persists for up to 7 days. Normal cellular proliferation returns by 2 weeks. Pre-treatment of both non-tumour-bearing and MDA-MB-468 tumour-bearing mice with UCN-01 prior to bolus 5-FU (450 mg/kg) yielded enhanced therapeutic efficacy with significantly decreased tumour volumes and increased survival. CONCLUSIONS UCN-01 mediates a specific, reversible G1 arrest of normal cells in vivo and provides a cytoprotective strategy that decreases toxicity of cytotoxic chemotherapy without compromising efficacy.
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Affiliation(s)
- Benjamin B Mull
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - J Andrew Livingston
- Department of Sarcoma Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Nalini Patel
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Tuyen Bui
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Kelly K Hunt
- Department of Breast Surgical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Khandan Keyomarsi
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
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Carroll TD, Newton IP, Chen Y, Blow JJ, Näthke I. Lgr5 + intestinal stem cells reside in an unlicensed G 1 phase. J Cell Biol 2018; 217:1667-1685. [PMID: 29599208 PMCID: PMC5940300 DOI: 10.1083/jcb.201708023] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 01/23/2018] [Accepted: 02/27/2018] [Indexed: 12/21/2022] Open
Abstract
During late mitosis and the early G1 phase, the origins of replication are licensed by binding to double hexamers of MCM2-7. In this study, we investigated how licensing and proliferative commitment are coupled in the epithelium of the small intestine. We developed a method for identifying cells in intact tissue containing DNA-bound MCM2-7. Interphase cells above the transit-amplifying compartment had no DNA-bound MCM2-7, but still expressed the MCM2-7 protein, suggesting that licensing is inhibited immediately upon differentiation. Strikingly, we found most proliferative Lgr5+ stem cells are in an unlicensed state. This suggests that the elongated cell-cycle of intestinal stem cells is caused by an increased G1 length, characterized by dormant periods with unlicensed origins. Significantly, the unlicensed state is lost in Apc-mutant epithelium, which lacks a functional restriction point, causing licensing immediately upon G1 entry. We propose that the unlicensed G1 phase of intestinal stem cells creates a temporal window when proliferative fate decisions can be made.
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Affiliation(s)
- Thomas D Carroll
- Cell and Developmental Biology, University of Dundee, Dundee, Scotland, UK
| | - Ian P Newton
- Cell and Developmental Biology, University of Dundee, Dundee, Scotland, UK
| | - Yu Chen
- Cell and Developmental Biology, University of Dundee, Dundee, Scotland, UK
| | - J Julian Blow
- Centre for Gene Regulation and Expression, University of Dundee, Dundee, Scotland, UK
| | - Inke Näthke
- Cell and Developmental Biology, University of Dundee, Dundee, Scotland, UK
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Peregrina K, Houston M, Daroqui C, Dhima E, Sellers RS, Augenlicht LH. Vitamin D is a determinant of mouse intestinal Lgr5 stem cell functions. Carcinogenesis 2014; 36:25-31. [PMID: 25344836 DOI: 10.1093/carcin/bgu221] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Lgr5+ intestinal crypt base columnar cells function as stem cells whose progeny populate the villi, and Lgr5+ cells in which Apc is inactivated can give rise to tumors. Surprisingly, these Lgr5+ stem cell properties were abrogated by the lower dietary vitamin D and calcium in a semi-purified diet that promotes both genetically initiated and sporadic intestinal tumors. Inactivation of the vitamin D receptor in Lgr5+ cells established that compromise of Lgr5 stem cell function was a rapid, cell autonomous effect of signaling through the vitamin D receptor. The loss of Lgr5 stem cell function was associated with presence of Ki67 negative Lgr5+ cells at the crypt base. Therefore, vitamin D, a common nutrient and inducer of intestinal cell maturation, is an environmental factor that is a determinant of Lgr5+ stem cell functions in vivo. Since diets used in reports that establish and dissect mouse Lgr5+ stem cell activity likely provided vitamin D levels well above the range documented for human populations, the contribution of Lgr5+ cells to intestinal homeostasis and tumor formation in humans may be significantly more limited, and variable in the population, then suggested by published rodent studies.
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Affiliation(s)
- Karina Peregrina
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Michele Houston
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Cecilia Daroqui
- Clinica Reina Fabiola, Oncativo 1248, Cordoba 5004, Argentina
| | - Elena Dhima
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | | | - Leonard H Augenlicht
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA, Department of Cell Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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Xiao L, Rao JN, Zou T, Liu L, Cao S, Martindale JL, Su W, Chung HK, Gorospe M, Wang JY. miR-29b represses intestinal mucosal growth by inhibiting translation of cyclin-dependent kinase 2. Mol Biol Cell 2013; 24:3038-46. [PMID: 23904268 PMCID: PMC3784378 DOI: 10.1091/mbc.e13-05-0287] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The epithelium of the intestinal mucosa is a rapidly self-renewing tissue in the body, and defects in the renewal process occur commonly in various disorders. miR-29b functions as a biological repressor of normal intestinal mucosal growth by repressing CDK2 translation through direct interaction with its mRNA, representing a novel therapeutic target for patients with mucosal atrophy. The epithelium of the intestinal mucosa is a rapidly self-renewing tissue in the body, and defects in the renewal process occur commonly in various disorders. microRNAs (miRNAs) posttranscriptionally regulate gene expression and are implicated in many aspects of cellular physiology. Here we investigate the role of miRNA-29b (miR-29b) in the regulation of normal intestinal mucosal growth and further validate its target mRNAs. miRNA expression profiling studies reveal that growth inhibition of the small intestinal mucosa is associated with increased expression of numerous miRNAs, including miR-29b. The simple systemic delivery of locked nucleic acid–modified, anti–miR-29b-reduced endogenous miR-29b levels in the small intestinal mucosa increases cyclin-dependent kinase 2 (CDK2) expression and stimulates mucosal growth. In contrast, overexpression of the miR-29b precursor in intestinal epithelial cells represses CDK2 expression and results in growth arrest in G1 phase. miR-29b represses CDK2 translation through direct interaction with the cdk2 mRNA via its 3′-untranslated region (3′-UTR), whereas point mutation of miR-29b binding site in the cdk2 3′-UTR prevents miR-29b–induced repression of CDK2 translation. These results indicate that miR-29b inhibits intestinal mucosal growth by repressing CDK2 translation.
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Affiliation(s)
- Lan Xiao
- Cell Biology Group, Department of Surgery, University of Maryland School of Medicine, Baltimore, MD 21201 Department of Pathology, University of Maryland School of Medicine, Baltimore, MD 21201 Baltimore Veterans Affairs Medical Center, Baltimore, MD 21201 Laboratory of Genetics, National Institute on Aging-Intramural Research Program, National Institutes of Health, Baltimore, MD 21224
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5
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Papetti M, Augenlicht LH. Mybl2, downregulated during colon epithelial cell maturation, is suppressed by miR-365. Am J Physiol Gastrointest Liver Physiol 2011; 301:G508-18. [PMID: 21737779 PMCID: PMC3174536 DOI: 10.1152/ajpgi.00066.2011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Altered profiles of gene expression reflect the reprogramming of intestinal epithelial cells during their maturation along the crypt-luminal axis. To focus on genes important in this process, and how they in turn are regulated, we identified 14 transcripts commonly downregulated in expression during lineage-specific maturation of the immortalized cell lines Caco-2 (absorptive), HT29Cl16E (goblet), and HT29Cl19A (secretory) induced by contact inhibition of growth or the short-chain fatty acid butyrate. One such gene, Mybl2 (Myb-related protein B), has been linked to the stem cell phenotype, and we report is also markedly suppressed in maturing cells along the crypt-luminal axis in vivo. Mybl2 is not significantly downregulated transcriptionally during colon cell maturation, but we identified a potential micro-RNA (miRNA)-binding sequence in the Mybl2 3'-untranslated region that mediates reporter gene suppression in differentiating colon cells. Accordingly, miRNAs predicted to bind this functional target are upregulated in differentiating colon epithelial cells in vitro and in vivo; expression of one of these, hsa-miR-365 (but not hsa-324-5p), suppresses Mybl2 protein expression in proliferating Caco-2 cells. These data demonstrate that miRNA silencing plays an important role in regulating gene expression in maturing colon epithelial cells, and that utilizing a target-centered approach, rather than profiling global miRNA expression, can identify physiologically relevant, functional miRNAs.
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Affiliation(s)
- Michael Papetti
- Department of Oncology, Albert Einstein Cancer Center, Montefiore Medical Center, Bronx, New York, USA.
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Paneth cell marker expression in intestinal villi and colon crypts characterizes dietary induced risk for mouse sporadic intestinal cancer. Proc Natl Acad Sci U S A 2011; 108:10272-7. [PMID: 21652773 DOI: 10.1073/pnas.1017668108] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Nutritional and genetic risk factors for intestinal tumors are additive on mouse tumor phenotype, establishing that diet and genetic factors impact risk by distinct combinatorial mechanisms. In a mouse model of dietary-induced sporadic small and large intestinal cancer in WT mice in which tumor etiology, lag, incidence, and frequency reflect >90% of intestinal cancer in Western societies, dietary-induced risk altered gene expression profiles predominantly in villus cells of the histologically normal mucosa, in contrast to targeting of crypt cells by inheritance of an Apc(1638N) allele or homozygous inactivation of p21(Waf1/cip1), and profiles induced by each risk factor were distinct at the gene or functional group level. The dietary-induced changes in villus cells encompassed ectopic expression of Paneth cell markers (a lineage normally confined to the bottom of small intestinal crypts), elevated expression of the Wnt receptor Fzd5 and of EphB2 (genes necessary for Paneth cell differentiation and localization to the crypt bottom), and increased Wnt signaling in villus cells. Ectopic elevation of these markers was also present in the colon crypts, which are also sites of sporadic tumors in the nutritional model. Elevating dietary vitamin D(3) and calcium, which prevents tumor development, abrogated these changes in the villus and colon cells. Thus, common intestinal cancer driven by diet involves mechanisms of tumor development distinct from those mechanisms that cause tumors induced by the rare inheritance of a mutant adenomatous polyposis coli (Apc) allele. This is fundamental for understanding how common sporadic tumors arise and in evaluating relative risk in the population.
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Cherbuy C, Honvo-Houeto E, Bruneau A, Bridonneau C, Mayeur C, Duée PH, Langella P, Thomas M. Microbiota matures colonic epithelium through a coordinated induction of cell cycle-related proteins in gnotobiotic rat. Am J Physiol Gastrointest Liver Physiol 2010; 299:G348-57. [PMID: 20466941 DOI: 10.1152/ajpgi.00384.2009] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Previous studies have suggested that intestinal microbiota modulates colonic epithelium renewal. The objective of our work was to study the effects of microbiota on colonic epithelium structure and cell cycle-related proteins by using gnotobiotic rats. Colonic crypts and amount of cell cycle-related proteins were compared between germ-free (GF), conventional (CV), and conventionalized rats by histochemistry and Western blot. Ki67 and proliferating cell nuclear antigen (PCNA) were used as surrogates for proliferative cells; p21(cip1) and p27(kip1) were markers of cell cycle arrest; anti- and proapoptotic proteins, Bcl2 and Bax, respectively, were also studied. We observed 40% increase of the crypt proliferative area 2 days after inoculation of GF rats with a complex microbiota. This recruitment of proliferative cells may account for the 30% increase of crypt depth observed between CV and GF rats. The hyperproliferative boost induced by microbiota was compensated by a fourfold increase of p21(cip1) and p27(kip1) involved in cell cycle arrest and a 30% drop of antiapoptotic Bcl2 protein while Bax was unchanged. Inductions of p21(cip1), p27(kip1), and PCNA protein were not paralleled by an increase of the corresponding mRNA. We also showed that p21(cip1) induction by microbiota was partially restored by Bacteroides thetaiotaomicron, Ruminococcus gnavus, and Clostridium paraputrificum. Colonization of the colon by a complex microbiota increases the crypt depth of colon epithelium. This event takes place in conjunction with a multistep process: a hyperproliferative boost accompanied by compensatory events as induction of p21(cip1) and p27(kip1) and decrease of Bcl2.
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Affiliation(s)
- Claire Cherbuy
- Institut National de la Recherche Agronomique, MICALIS, UMR, Pôle Ecosystèmes, Jouy-en-Josas, France.
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Wang D, Pezo RC, Corner G, Sison C, Lesser ML, Shenoy SM, Mariadason JM, Singer RH, Augenlicht LH. Altered dynamics of intestinal cell maturation in Apc1638N/+ mice. Cancer Res 2010; 70:5348-57. [PMID: 20570902 DOI: 10.1158/0008-5472.can-09-4593] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Novel imaging of active transcription sites in interphase nuclei of intestinal epithelial cells in situ showed that key genes associated with Wnt and Notch signaling were dynamically regulated as the cells underwent normal maturation during their migration along the mouse crypt-villus axis (CVA). However, oscillating patterns of activation of these genes were displaced along this axis in the histologically normal intestinal mucosa of Apc(1638N/+) mice before tumor development. Gene expression profiling then showed that the normal reprogramming of cells along the CVA was dampened in the Apc(1638N/+) mice, with an overrepresentation of c-myc target genes among those loci affected in the mutant mice. Moreover, in the Apc(1638N/+) mice, there was a perturbed pattern of expression of lineage-specific markers along the CVA consistent with transcription site repression of the Math1 gene, and genes encoding enzymes of every step of the tricarboxylic acid cycle were downregulated in the crypt of Apc(1638N/+) mice compared with WT, but not in the villus. These changes may alter energy metabolism and generate a pseudohypoxic state, suggested by elevated expression of Hif1alpha and its target genes. Thus, although intestinal tumors develop in Apc(1638N/+) mice on focal loss or inactivation of the WT allele, our results show that in the Apc(1638N/+) mouse, inheritance of only a single WT Apc allele perturbs the dynamic and complex reprogramming underlying normal cell maturation, which links epithelial function and homeostasis with architectural organization of the intestine.
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Affiliation(s)
- Donghai Wang
- Department of Medicine, Montefiore Medical Center, Bronx, New York 10467, USA
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9
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Guo J, Longshore S, Nair R, Warner BW. Retinoblastoma protein (pRb), but not p107 or p130, is required for maintenance of enterocyte quiescence and differentiation in small intestine. J Biol Chem 2008; 284:134-140. [PMID: 18981186 DOI: 10.1074/jbc.m806133200] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The function of retinoblastoma protein (pRb) in the regulation of small intestine epithelial cell homeostasis has been challenged by several groups using various promoter-based Cre transgenic mouse lines. Interestingly, different pRb deletion systems yield dramatically disparate small intestinal phenotypes. These findings confound the function of pRb in this dynamic tissue. In this study, Villin-Cre transgenic mice were crossed with Rb (flox/flox) mice to conditionally delete pRb protein in small intestine enterocytes. We discovered a novel hyperplasia phenotype as well as ectopic cell cycle reentry within villus enterocytes in the small intestine. This phenotype was not seen in other pRb family member (p107 or p130) null mice. Using a newly developed crypt/villus isolation method, we uncovered that expression of pRb was undetectable, whereas proliferating cell nuclear antigen, p107, cyclin E, cyclin D3, Cdk2, and Cdc2 were dramatically increased in pRb-deficient villus cells. Cyclin A, cyclin D1, cyclin D2, and Cdk4/6 expression was not affected by absent pRb expression. pRb-deficient villus cells appeared capable of progressing to mitosis but with higher rates of apoptosis. However, the cycling villus enterocytes were not completely differentiated as gauged by significant reduction of intestinal fatty acid-binding protein expression. In summary, pRb, but not p107 or p130, is required for maintaining the postmitotic villus cell in quiescence, governing the expression of cell cycle regulatory proteins, and completing of absorptive enterocyte differentiation in the small intestine.
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Affiliation(s)
- Jun Guo
- Division of Pediatric Surgery, Washington University School of Medicine, St. Louis Children's Hospital, St. Louis, Missouri 63110
| | - Shannon Longshore
- Division of Pediatric Surgery, Washington University School of Medicine, St. Louis Children's Hospital, St. Louis, Missouri 63110
| | - Rajalakshmi Nair
- Division of Pediatric Surgery, Washington University School of Medicine, St. Louis Children's Hospital, St. Louis, Missouri 63110
| | - Brad W Warner
- Division of Pediatric Surgery, Washington University School of Medicine, St. Louis Children's Hospital, St. Louis, Missouri 63110.
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Flandez M, Guilmeau S, Blache P, Augenlicht LH. KLF4 regulation in intestinal epithelial cell maturation. Exp Cell Res 2008; 314:3712-23. [PMID: 18977346 DOI: 10.1016/j.yexcr.2008.10.004] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2008] [Revised: 09/19/2008] [Accepted: 10/06/2008] [Indexed: 12/13/2022]
Abstract
The Krüppel-like factor 4 (KLF4) transcription factor suppresses tumorigenesis in gastrointestinal epithelium. Thus, its expression is decreased in gastric and colon cancers. Moreover, KLF4 regulates both differentiation and growth that is likely fundamental to its tumor suppressor activity. We dissected the expression of Klf4 in the normal mouse intestinal epithelium along the crypt-villus and cephalo-caudal axes. Klf4 reached its highest level in differentiated cells of the villus, with levels in the duodenum>jejunum>ileum, in inverse relation to the representation of goblet cells in these regions, the lineage previously linked to KLF4. In parallel, in vitro studies using HT29cl.16E and Caco2 colon cancer cell lines clarified that KLF4 increased coincident with differentiation along both the goblet and absorptive cell lineages, respectively, and that KLF4 levels also increased during differentiation induced by the short chain fatty acid butyrate, independently of cell fate. Moreover, we determined that lower levels of KLF4 expression in the proliferative compartment of the intestinal epithelium are regulated by the transcription factors TCF4 and SOX9, an effector and a target, respectively, of beta-catenin/Tcf signaling, and independently of CDX2. Thus, reduced levels of KLF4 tumor suppressor activity in colon tumors may be driven by elevated beta-catenin/Tcf signaling.
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Affiliation(s)
- M Flandez
- Department of Oncology, Albert Einstein Cancer Center, Montefiore Medical Center, 111 East 210th St. Bronx, NY 10467, USA.
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Wei W, Englander EW. DNA polymerase beta-catalyzed-PCNA independent long patch base excision repair synthesis: a mechanism for repair of oxidatively damaged DNA ends in post-mitotic brain. J Neurochem 2008; 107:734-44. [PMID: 18752643 DOI: 10.1111/j.1471-4159.2008.05644.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Oxidative DNA damage incidental to normal respiratory metabolism poses a particular threat to genomes of highly metabolic-long lived cells. We show that post-mitotic brain has capacity to repair oxidatively damaged DNA ends, which are targets of the long patch (LP) base excision repair (BER) subpathway. LP-BER relies, in part, on proteins associated with DNA replication, including proliferating cell nuclear antigen and is inherent to proliferating cells. Nonetheless, repair products are generated with brain extracts, albeit at slow rates, in the case of 5'-DNA ends modeled with tetrahydrofuran (THF). THF at this position is refractory to DNA polymerase beta 5'-deoxyribose 5-phosphate lyase activity and drives repair into the LP-BER subpathway. Comparison of repair of 5'-THF-blocked termini in the post-mitotic rat brain and proliferative intestinal mucosa, revealed that in mucosa, resolution of damaged 5'-termini is accompanied by formation of larger repair products. In contrast, adducts targeted by the single nucleotide BER are proficiently repaired with both extracts. Our findings reveal mechanistic differences in BER processes selective for the brain versus proliferative tissues. The differences highlight the physiological relevance of the recently proposed 'Hit and Run' mechanism of alternating cleavage/synthesis steps, in the proliferating cell nuclear antigen-independent LP-BER process.
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Affiliation(s)
- Wei Wei
- Department of Surgery, University of Texas Medical Branch, Galveston, Texas 77555-1220, USA
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Guilmeau S, Flandez M, Bancroft L, Sellers RS, Tear B, Stanley P, Augenlicht LH. Intestinal deletion of Pofut1 in the mouse inactivates notch signaling and causes enterocolitis. Gastroenterology 2008; 135:849-60, 860.e1-6. [PMID: 18621050 PMCID: PMC3207497 DOI: 10.1053/j.gastro.2008.05.050] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2007] [Revised: 05/05/2008] [Accepted: 05/15/2008] [Indexed: 01/05/2023]
Abstract
BACKGROUND & AIMS Notch downstream targets are fundamental to intestinal cell lineage commitment and are suggested as therapeutic targets for colon cancer cells. However, the role of endogenous Notch signaling through receptor-ligand interaction, and effects of its longer term down-regulation on intestinal homeostasis, are unclear. METHODS To address these issues, the gene encoding protein O-fucosyltransferase 1, an enzyme required for Notch ligand binding and thus activation of all Notch receptors, was deleted in the mouse intestinal and colonic epithelium, through Villin-Cre-mediated recombination. RESULTS Pofut1 deletion inactivated Notch signaling, giving rise to smaller but viable mice. These mice exhibited a large increase in all intestinal secretory cell lineages, which accumulated in the crypts, resulting in crypt hyperplasia. Although proliferating cells were largely reduced in the colon, the transit amplifying compartment was maintained in the upper crypts of the intestinal mucosa. By 9 months, these perturbations in cell maturation altered mucus-associated gut microbiota and caused chronic intestinal inflammation, with evidence of bacterial translocation to the mesenteric lymph nodes, macrophage, and T-lymphocyte infiltration, and Th1/Th17 immune response. Dysplastic foci were also observed in Pofut1-deficient small intestine with occasional progression to tumor formation. CONCLUSIONS Mucus hypersecretion upon Pofut1 inactivation is accompanied by alteration of the mucus-associated flora, which likely contributes to the development of enterocolitis. Therefore, these data identify important potential complications in strategies to target Notch signaling in therapeutic approaches to colon cancer.
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Affiliation(s)
- Sandra Guilmeau
- Department of Oncology, Albert Einstein Cancer Center, Montefiore Hospital, Bronx, New York 10467, USA.
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Huang CS, Ho WL, Lee WS, Sheu MT, Wang YJ, Tu SH, Chen RJ, Chu JS, Chen LC, Lee CH, Tseng H, Ho YS, Wu CH. SP1-regulated p27/Kip1 gene expression is involved in terbinafine-induced human A431 cancer cell differentiation: An in vitro and in vivo study. Biochem Pharmacol 2008; 75:1783-96. [DOI: 10.1016/j.bcp.2008.02.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2007] [Revised: 02/01/2008] [Accepted: 02/07/2008] [Indexed: 12/21/2022]
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Zheng Y, Bie W, Yang R, Perekatt AO, Poole AJ, Tyner AL. Functions of p21 and p27 in the regenerating epithelial linings of the mouse small and large intestine. Cancer Biol Ther 2008; 7:873-9. [PMID: 18344686 DOI: 10.4161/cbt.7.6.5868] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The epithelial linings of the small and large intestine are rapidly turned over and provide an ideal system for exploring links between differentiation and regulation of cell cycle exit. We utilized wild type, p21-/-, p27-/- and p21/p27-/- mice to address contributions of the Cdk inhibitors p21 and p27 to proliferation and differentiation in the mouse gastrointestinal tract. We did not detect any significant differences in proliferation, and all differentiated epithelial cell lineages were represented in all four genotypes. These data indicate that p21 and p27 do not play essential roles in the regulation of normal epithelial renewal in the intestine. These Cdk inhibitors are not needed in vivo for either assembly of Cdk/Cyclin complexes that drive active proliferation, or inhibition of Cdk/Cyclin complexes during cell cycle exit. However, expression of Cyclin D2 and to a lesser degree Cyclin D3 was reduced in p27-/- and p21/p27-/- mice, indicating a unique role for p27 in the regulation of these specific D-type Cyclins in vivo. In the absence of p27, reduced levels of Cyclin D2 and D3 may help to counteract increased proproliferative signals in the intestine.
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Affiliation(s)
- Yu Zheng
- University of Illinois College of Medicine, Department of Biochemistry and Molecular Genetics, Chicago, Illinois 60607, USA
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