151
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Cao C, Wan Y. Parameters of protection against ultraviolet radiation-induced skin cell damage. J Cell Physiol 2009; 220:277-84. [PMID: 19360745 DOI: 10.1002/jcp.21780] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Epidemiological and experimental evidence has supported the notion that solar ultraviolet (UV) radiation is the leading cause of skin cell damage and skin cancer. Non-melanoma skin cancer, one of the malignancies with the most rapidly increasing incidence, is suggested to be directly related to the total exposure to solar UV light. Over the past few years, the mechanisms of cellular responses to UV radiation have received unprecedented attention. Understanding how skin cells respond to UV radiation will undoubtedly help decipher what goes wrong in a variety of clinical skin disorders including skin cancer and will facilitate the development of novel therapeutic strategies. In the past decade, studies have established that UV radiation induces multifarious signal transduction pathways, some of which lead to apoptotic cell death, while others protect against this process. In this review, we summarize some of the most recent progresses regarding the involvement of multiple signal pathways in UV radiation-induced apoptosis in skin cells, especially in keratinocytes. These pathways include pro-apoptosis components such as MAPK, AMPK, and p53 as well as pro-survival components, namely, AKT and mTORC complexes.
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Affiliation(s)
- Cong Cao
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI 02912, USA.
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152
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Wang Z, Li Y, Banerjee S, Sarkar FH. Emerging role of Notch in stem cells and cancer. Cancer Lett 2009; 279:8-12. [PMID: 19022563 PMCID: PMC2699045 DOI: 10.1016/j.canlet.2008.09.030] [Citation(s) in RCA: 176] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2008] [Revised: 09/21/2008] [Accepted: 09/12/2008] [Indexed: 12/21/2022]
Abstract
The Notch signaling pathway is known to be responsible for maintaining a balance between cell proliferation and death and, as such, plays important roles in the formation of many types of human tumors. Recently, Notch signaling pathway has been shown to control stem cell self-renewal and multi-potency. As many cancers are thought to be developed from a number of cancer stem-like cells, which are also known to be linked with the acquisition of epithelial-mesenchymal transition (EMT); and thus suggesting an expanding role of Notch signaling in human tumor progression.
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Affiliation(s)
- Zhiwei Wang
- Department of Pathology, Karmanos Cancer Institute, Wayne State University School of Medicine, 9374 Scott Hall, 540 E Canfield, Detroit, MI 48201, United States
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153
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Zhang F, Zhang T, Jiang T, Zhang R, Teng ZH, Li C, Gu ZP, Mei Q. Wortmannin potentiates roscovitine-induced growth inhibition in human solid tumor cells by repressing PI3K/Akt pathway. Cancer Lett 2009; 286:232-9. [PMID: 19541408 DOI: 10.1016/j.canlet.2009.05.039] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2008] [Revised: 03/03/2009] [Accepted: 05/27/2009] [Indexed: 11/18/2022]
Abstract
Roscovitine has been reported to have anti-tumor effects in some cancer cell lines. The phosphatidylinositol-3-kinase (PI3K) signaling, which activates protein kinase B (PKB)/Akt, is known to mediate cell survival. The current study examined the role of wortmannin, a PI3K inhibitor, as a chemosensitizer for roscovitine and its proposed mechanism of action. The results showed that wortmannin significantly chemosensitized three human tumor cell lines (A549, HCT116 and HeLa cells). In A549 cells, wortmannin increased roscovitine-induced apoptosis in a dose-dependent manner, which was correlated with the inhibition of phosphorylated PKB/Akt level. Wortmannin enhanced the effects of roscovitine by causing pronounced reduction of mitochondrial transmembrane potential (MMP) and increases of cytochrome c release and active caspase-3, as well as enhanced activation of Bax and Bad, including Bax oligomerization and mitochondrial translocation of Bax and Bad. Taken together, these results provide evidence for the potential application of roscovitine/wormannin combination in clinical treatment for solid tumors.
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Affiliation(s)
- Feng Zhang
- Department of Pharmacology, The Fourth Military Medical University, Xi'an 710032, China
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154
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Chadwick N, Zeef L, Portillo V, Fennessy C, Warrander F, Hoyle S, Buckle AM. Identification of novel Notch target genes in T cell leukaemia. Mol Cancer 2009; 8:35. [PMID: 19508709 PMCID: PMC2698846 DOI: 10.1186/1476-4598-8-35] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2009] [Accepted: 06/09/2009] [Indexed: 11/30/2022] Open
Abstract
Background Dysregulated Notch signalling is believed to play an important role in the development and maintenance of T cell leukaemia. At a cellular level, Notch signalling promotes proliferation and inhibits apoptosis of T cell acute lymphoblastic leukaemia (T-ALL) cells. In this study we aimed to identify novel transcriptional targets of Notch signalling in the T-ALL cell line, Jurkat. Results RNA was prepared from Jurkat cells retrovirally transduced with an empty vector (GFP-alone) or vectors containing constitutively active forms of Notch (N1ΔE or N3ΔE), and used for Affymetrix microarray analysis. A subset of genes found to be regulated by Notch was chosen for real-time PCR validation and in some cases, validation at the protein level, using several Notch-transduced T-ALL and non-T-ALL leukaemic cell lines. As expected, several known transcriptional target of Notch, such as HES1 and Deltex, were found to be overexpressed in Notch-transduced cells, however, many novel transcriptional targets of Notch signalling were identified using this approach. These included the T cell costimulatory molecule CD28, the anti-apoptotic protein GIMAP5, and inhibitor of DNA binding 1 (1D1). Conclusion The identification of such downstream Notch target genes provides insights into the mechanisms of Notch function in T cell leukaemia, and may help identify novel therapeutic targets in this disease.
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Affiliation(s)
- Nicholas Chadwick
- Faculty of Life Sciences, Manchester Interdisciplinary Biocenter, University of Manchester, Manchester, UK.
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155
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Meurette O, Stylianou S, Rock R, Collu GM, Gilmore AP, Brennan K. Notch Activation Induces Akt Signaling via an Autocrine Loop to Prevent Apoptosis in Breast Epithelial Cells. Cancer Res 2009; 69:5015-22. [DOI: 10.1158/0008-5472.can-08-3478] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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156
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Ischenko I, Seeliger H, Kleespies A, Angele MK, Eichhorn ME, Jauch KW, Bruns CJ. Pancreatic cancer stem cells: new understanding of tumorigenesis, clinical implications. Langenbecks Arch Surg 2009; 395:1-10. [PMID: 19421768 DOI: 10.1007/s00423-009-0502-z] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Accepted: 04/24/2009] [Indexed: 01/12/2023]
Abstract
PURPOSE Since the discovery of cancer cells with stem-like characteristics in hematopoietic malignancies and, more recently, in solid tumors, enormous attention has been paid to the stem-cell nature of pancreatic cancer. Among the most important properties of cancer stem cells their high capacity for tumorigenicity as well as their ability to metastasize is under special research interest today. METHODS Here, we give a brief overview of main components used to confirm the stem-cell-like behavior of putative cancer stem cells and discuss markers and methods for identifying them in pancreatic cancer. Finally, the review provides some new suggestions as to how specifically target these cells and improve current therapy regimens. RESULTS The cancer stem-cell hypothesis is a fundamentally different model of carcinogenesis composed of two separate but dependent on each other characteristics of stem cells--aberrant activation of their tightly regulated processes of self-renewal and differentiation and their resistance towards chemo- and radiotherapy. The cancer stem cells may further be identified based on their expression of cell surface markers or their functional characteristics. The concept of molecular targeting of such highly tumorigenic cancer cells aimed to sensitize tumors toward conventional therapies and effectively abrogate tumor growth and metastasis. CONCLUSIONS The presence of cancer stem cells in pancreatic tumors has prognostic relevance and influences therapeutic response. Evidence suggests that metastatic potential may be conferred to these highly tumorigenic cells as well. A better understanding of the biological behavior of these cells may further improve therapeutic approaches and outcomes in patients with this devastating disease.
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Affiliation(s)
- Ivan Ischenko
- Department of Surgery, Grosshadern Campus, Medical Center of the University of Munich, Marchioninistr. 15, Munich, 81377, Germany.
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157
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Nutlin-3 up-regulates the expression of Notch1 in both myeloid and lymphoid leukemic cells, as part of a negative feedback antiapoptotic mechanism. Blood 2009; 113:4300-8. [DOI: 10.1182/blood-2008-11-187708] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Abstract
The small molecule inhibitor of the MDM2/p53 interaction Nutlin-3 significantly up-regulated the steady-state mRNA and protein levels of Notch1 in TP53wild-type (OCI, SKW6.4) but not in TP53deleted (HL-60) or TP53mutated (BJAB) leukemic cell lines. A direct demonstration that NOTCH1 was a transcriptional target of p53 in leukemic cells was obtained in experiments carried out with siRNA for p53. Moreover, inhibition of Notch1 expression using Notch1-specific siRNA significantly increased cytotoxicity in TP53wild-type leukemic cells. Of note, Nutlin-3 up-regulated Notch1 expression also in primary TP53wild-type B-chronic lymphocytic leukemia (B-CLL) cells and the combined use of Nutlin-3 plus pharmacological γ-secretase inhibitors of the Notch signaling showed a synergistic cytotoxicity in both TP53wild-type leukemic cell lines and primary B-CLL cells. A potential drawback of γ-secretase inhibitors was their ability to enhance osteoclastic maturation of normal circulating preosteoclasts induced by RANKL + M-CSF. Notwithstanding, Nutlin-3 completely suppressed osteoclastogenesis irrespective of the presence of γ-secretase inhibitors. Taken together, these data indicate that the p53-dependent up-regulation of Notch1 in response to Nutlin-3 represents an antiapoptotic feedback mechanism able to restrain the potential therapeutic efficacy of Nutlin-3 in hematologic malignancies. Therefore, therapeutic combinations of Nutlin-3 + γ-secretase inhibitors might potentiate the cytotoxicity of Nutlin-3 in p53wild-type leukemic cells.
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158
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Cencic R, Carrier M, Galicia-Vázquez G, Bordeleau ME, Sukarieh R, Bourdeau A, Brem B, Teodoro JG, Greger H, Tremblay ML, Porco JA, Pelletier J. Antitumor activity and mechanism of action of the cyclopenta[b]benzofuran, silvestrol. PLoS One 2009; 4:e5223. [PMID: 19401772 PMCID: PMC2671147 DOI: 10.1371/journal.pone.0005223] [Citation(s) in RCA: 232] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2009] [Accepted: 03/19/2009] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND Flavaglines are a family of natural products from the genus Aglaia that exhibit anti-cancer activity in vitro and in vivo and inhibit translation initiation. They have been shown to modulate the activity of eIF4A, the DEAD-box RNA helicase subunit of the eukaryotic initiation factor (eIF) 4F complex, a complex that stimulates ribosome recruitment during translation initiation. One flavagline, silvestrol, is capable of modulating chemosensitivity in a mechanism-based mouse model. METHODOLOGY/PRINCIPAL FINDINGS Among a number of flavagline family members tested herein, we find that silvestrol is the more potent translation inhibitor among these. We find that silvestrol impairs the ribosome recruitment step of translation initiation by affecting the composition of the eukaryotic initiation factor (eIF) 4F complex. We show that silvestrol exhibits significant anticancer activity in human breast and prostate cancer xenograft models, and that this is associated with increased apoptosis, decreased proliferation, and inhibition of angiogenesis. We demonstrate that targeting translation by silvestrol results in preferential inhibition of weakly initiating mRNAs. CONCLUSIONS/SIGNIFICANCE Our results indicate that silvestrol is a potent anti-cancer compound in vivo that exerts its activity by affecting survival pathways as well as angiogenesis. We propose that silvestrol mediates its effects by preferentially inhibiting translation of malignancy-related mRNAs. Silvestrol appears to be well tolerated in animals.
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MESH Headings
- Animals
- Antineoplastic Agents, Phytogenic/chemistry
- Antineoplastic Agents, Phytogenic/pharmacology
- Base Sequence
- Breast Neoplasms/drug therapy
- Breast Neoplasms/genetics
- Breast Neoplasms/pathology
- Cell Line, Tumor
- Cells, Cultured
- Eukaryotic Initiation Factor-4E/metabolism
- Female
- Humans
- Male
- Mice
- Mice, Nude
- Neoplasm Transplantation
- Neovascularization, Pathologic/prevention & control
- Prostatic Neoplasms/drug therapy
- Prostatic Neoplasms/genetics
- Prostatic Neoplasms/pathology
- Protein Biosynthesis/drug effects
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA, Neoplasm/genetics
- RNA, Neoplasm/metabolism
- Transplantation, Heterologous
- Triterpenes/chemistry
- Triterpenes/pharmacology
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Affiliation(s)
- Regina Cencic
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada
| | - Marilyn Carrier
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada
| | | | | | - Rami Sukarieh
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada
| | - Annie Bourdeau
- Sunnybrook Health Sciences Centre and the Department of Immunology, University of Toronto, Toronto, Ontario, Canada
| | - Brigitte Brem
- Comparative Phytochemistry Department, Institute of Botany, University of Vienna, Vienna, Austria
| | - Jose G. Teodoro
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada
- Goodman Cancer Center, McGill University, Montreal, Quebec, Canada
| | - Harald Greger
- Comparative Phytochemistry Department, Institute of Botany, University of Vienna, Vienna, Austria
| | - Michel L. Tremblay
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada
- Goodman Cancer Center, McGill University, Montreal, Quebec, Canada
| | - John A. Porco
- Department of Chemistry, Center for Chemical Methodology and Library Development, Boston University, Boston, Massachusetts, United States of America
| | - Jerry Pelletier
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada
- Goodman Cancer Center, McGill University, Montreal, Quebec, Canada
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159
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A hierarchical cascade activated by non-canonical Notch signaling and the mTOR-Rictor complex regulates neglect-induced death in mammalian cells. Cell Death Differ 2009; 16:879-89. [PMID: 19265851 DOI: 10.1038/cdd.2009.20] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The regulation of cellular metabolism and survival by trophic factors is not completely understood. Here, we describe a signaling cascade activated by the developmental regulator Notch, which inhibits apoptosis triggered by neglect in mammalian cells. In this pathway, the Notch intracellular domain (NIC), which is released after interaction with ligand, converges on the kinase mammalian target of rapamycin (mTOR) and the substrate-defining protein rapamycin independent companion of mTOR (Rictor), culminating in the activation of the kinase Akt/PKB. Biochemical and molecular approaches using site-directed mutants identified AktS473 as a key downstream target in the antiapoptotic pathway activated by NIC. Despite the demonstrated requirement for Notch processing and its predominant nuclear localization, NIC function was independent of CBF1/RBP-J, an essential DNA-binding component required for canonical signaling. In experiments that placed spatial constraints on NIC, enforced nuclear retention abrogated antiapoptotic activity and a membrane-anchored form of NIC-blocked apoptosis through mTOR, Rictor and Akt-dependent signaling. We show that the NIC-mTORC2-Akt cascade blocks the apoptotic response triggered by removal of medium or serum deprivation. Consistently, membrane-tethered NIC, and AktS473 inhibited apoptosis triggered by cytokine deprivation in activated T cells. Thus, this study identifies a non-canonical signaling cascade wherein NIC integrates with multiple pathways to regulate cell survival.
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160
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Øyan AM, Anensen N, Bø TH, Stordrange L, Jonassen I, Bruserud Ø, Kalland KH, Gjertsen BT. Genes of cell-cell interactions, chemotherapy detoxification and apoptosis are induced during chemotherapy of acute myeloid leukemia. BMC Cancer 2009; 9:77. [PMID: 19265549 PMCID: PMC2673224 DOI: 10.1186/1471-2407-9-77] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2008] [Accepted: 03/05/2009] [Indexed: 01/11/2023] Open
Abstract
Background The molecular changes in vivo in acute myeloid leukemia cells early after start of conventional genotoxic chemotherapy are incompletely understood, and it is not known if early molecular modulations reflect clinical response. Methods The gene expression was examined by whole genome 44 k oligo microarrays and 12 k cDNA microarrays in peripheral blood leukocytes collected from seven leukemia patients before treatment, 2–4 h and 18–24 h after start of chemotherapy and validated by real-time quantitative PCR. Statistically significantly upregulated genes were classified using gene ontology (GO) terms. Parallel samples were examined by flow cytometry for apoptosis by annexin V-binding and the expression of selected proteins were confirmed by immunoblotting. Results Significant differential modulation of 151 genes were found at 4 h after start of induction therapy with cytarabine and anthracycline, including significant overexpression of 31 genes associated with p53 regulation. Within 4 h of chemotherapy the BCL2/BAX and BCL2/PUMA ratio were attenuated in proapoptotic direction. FLT3 mutations indicated that non-responders (5/7 patients, 8 versus 49 months survival) are characterized by a unique gene response profile before and at 4 h. At 18–24 h after chemotherapy, the gene expression of p53 target genes was attenuated, while genes involved in chemoresistance, cytarabine detoxification, chemokine networks and T cell receptor were prominent. No signs of apoptosis were observed in the collected cells, suggesting the treated patients as a physiological source of pre-apoptotic cells. Conclusion Pre-apoptotic gene expression can be monitored within hours after start of chemotherapy in patients with acute myeloid leukemia, and may be useful in future determination of therapy responders. The low number of patients and the heterogeneity of acute myeloid leukemia limited the identification of gene expression predictive of therapy response. Therapy-induced gene expression reflects the complex biological processes involved in clinical cancer cell eradication and should be explored for future enhancement of therapy.
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Affiliation(s)
- Anne Margrete Øyan
- Institute of Medicine, Hematology Section, University of Bergen, Bergen, Norway.
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161
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Meng RD, Shelton CC, Li YM, Qin LX, Notterman D, Paty PB, Schwartz GK. gamma-Secretase inhibitors abrogate oxaliplatin-induced activation of the Notch-1 signaling pathway in colon cancer cells resulting in enhanced chemosensitivity. Cancer Res 2009; 69:573-82. [PMID: 19147571 DOI: 10.1158/0008-5472.can-08-2088] [Citation(s) in RCA: 213] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Because Notch signaling is implicated in colon cancer tumorigenesis and protects cells from apoptosis by inducing prosurvival targets, it was hypothesized that inhibition of Notch signaling with gamma-secretase inhibitors (GSI) may enhance the chemosensitivity of colon cancer cells. We first show that the Notch-1 receptor, as well as its downstream target Hes-1, is up-regulated with colon cancer progression, similar to other genes involved in chemoresistance. We then report that chemotherapy induces Notch-1, as oxaliplatin, 5-fluorouracil (5-FU), or SN-38 (the active metabolite of irinotecan) induced Notch-1 intracellular domain (NICD) protein and activated Hes-1. Induction of NICD by oxaliplatin was caused by an increase in the activity and expression of gamma-secretase complex, as suppression of the protein subunit nicastrin with small interfering RNA (siRNA) prevented NICD induction after oxaliplatin. Subsequent inhibition of Notch-1 signaling with a sulfonamide GSI (GSI34) prevented the induction of NICD by chemotherapy and blunted Hes-1 activation. Blocking the activation of Notch signaling with GSI34 sensitized cells to chemotherapy and was synergistic with oxaliplatin, 5-FU, and SN-38. This chemosensitization was mediated by Notch-1, as inhibition of Notch-1 with siRNA enhanced chemosensitivity whereas overexpression of NICD increased chemoresistance. Down-regulation of Notch signaling also prevented the induction of prosurvival pathways, most notably phosphoinositide kinase-3/Akt, after oxaliplatin. In summary, colon cancer cells may up-regulate Notch-1 as a protective mechanism in response to chemotherapy. Therefore, combining GSIs with chemotherapy may represent a novel approach for treating metastatic colon cancers by mitigating the development of chemoresistance.
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Affiliation(s)
- Raymond D Meng
- Department of Medicine, Division of Solid Tumor Oncology, Laboratory of New Drug Development, Memorial Sloan-Kettering Cancer Center, New York, New York 10065, USA
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162
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Bansal K, Narayana Y, Patil SA, Balaji KN. M. bovis BCG induced expression of COX-2 involves nitric oxide-dependent and -independent signaling pathways. J Leukoc Biol 2009; 85:804-16. [PMID: 19228814 DOI: 10.1189/jlb.0908561] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
In a multifaceted immunity to mycobacterial infection, induced expression of cyclooxygenase-2 (COX-2) by Mycobacterium bovis bacillus Calmette-Guerin (BCG) may act as an important influencing factor for the effective host immunity. We here demonstrate that M. bovis BCG-triggered TLR2-dependent signaling leads to COX-2 and PGE2 expression in vitro in macrophages and in vivo in mice. Further, the presence of PGE2 could be demonstrated in sera or cerebrospinal fluid of tuberculosis patients. The induced COX-2 expression in macrophages is dependent on NF-kappaB activation, which is mediated by inducible NO synthase (iNOS)/NO-dependent participation of the members of Notch1-PI-3K signaling cascades as well as iNOS-independent activation of ERK1/2 and p38 MAPKs. Inhibition of iNOS activity abrogated the M. bovis BCG ability to trigger the generation of Notch1 intracellular domain (NICD), a marker for Notch1 signaling activation, as well as activation of the PI-3K signaling cascade. On the contrary, treatment of macrophages with 3-morpholinosydnonimine, a NO donor, resulted in a rapid increase in generation of NICD, activation of PI-3K pathway, as well as the expression of COX-2. Stable expression of NICD in RAW 264.7 macrophages resulted in augmented expression of COX-2. Further, signaling perturbations suggested the involvement of the cross-talk of Notch1 with members with the PI-3K signaling cascade. These results implicate the dichotomous nature of TLR2 signaling during M. bovis BCG-triggered expression of COX-2. In this perspective, we propose the involvement of iNOS/NO as one of the obligatory, early, proximal signaling events during M. bovis BCG-induced COX-2 expression in macrophages.
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Affiliation(s)
- Kushagra Bansal
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
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163
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Hancock MK, Kopp L, Bi K. High-Throughput Screening Compatible Cell-Based Assay for Interrogating Activated Notch Signaling. Assay Drug Dev Technol 2009; 7:68-79. [DOI: 10.1089/adt.2008.173] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Affiliation(s)
| | | | - Kun Bi
- Invitrogen Corporation, Madison, Wisconsin
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164
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Long L, Cao YD. Down-regulation of Notch1 and NF-κB by curcumin in breast cancer cells MDA-MB-231. Chin J Cancer Res 2009. [DOI: 10.1007/s11670-008-0294-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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165
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Bhonde MR, Gupte RD, Dadarkar SD, Jadhav MG, Tannu AA, Bhatt P, Bhatia DR, Desai NK, Deore V, Yewalkar N, Vishwakarma RA, Sharma S, Kumar S, Dagia NM. A novel mTOR inhibitor is efficacious in a murine model of colitis. Am J Physiol Gastrointest Liver Physiol 2008; 295:G1237-45. [PMID: 18927209 DOI: 10.1152/ajpgi.90537.2008] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Ulcerative colitis is an autoimmune-inflammatory disease characterized by increased proliferation of colonic epithelial cells, dysregulation of signal transduction pathways, elevated mucosal T cell activation, increased production of proinflammatory cytokines, and enhanced leukocyte infiltration into colonic interstitium. Several compounds that possess antiproliferative properties and/or inhibit cytokine production exhibit a therapeutic effect in murine models of colitis. Mammalian target of rapamycin (mTOR), a protein kinase regulating cell proliferation, is implicated in colon carcinogenesis. In this study, we report that a novel haloacyl aminopyridine-based molecule (P2281) is a mTOR inhibitor and is efficacious in a murine model of human colitis. In vitro studies using Western blot analysis and cell-based ELISA assays showed that P2281 inhibits mTOR activity in colon cancer cells. In vitro and in vivo assays of proinflammatory cytokine production revealed that P2281 diminishes induced IFN-gamma production but not TNF-alpha production, indicating preferential inhibitory effects of P2281 on T cell function. In the dextran sulfate sodium (DSS) model of colitis, 1) macroscopic colon observations demonstrated that P2281 significantly inhibited DSS-induced weight loss, improved rectal bleeding index, decreased disease activity index, and reversed DSS-induced shortening of the colon; 2) histological analyses of colonic tissues revealed that P2281 distinctly attenuated DSS-induced edema, prominently diminished the leukocyte infiltration in the colonic mucosa, and resulted in protection against DSS-induced crypt damage; and 3) Western blot analysis showed that P2281 blocks DSS-induced activation of mTOR. Collectively, these results provide direct evidence that P2281, a novel mTOR inhibitor, suppresses DSS-induced colitis by inhibiting T cell function and is a potential therapeutic for colitis. Given that compounds with anticancer activity show promising anti-inflammatory efficacy, our findings reinforce the cross-therapeutic functionality of potential drugs.
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Affiliation(s)
- Mandar R Bhonde
- Dept. of Pharmacology, Piramal Life Sciences Limited, 1 Nirlon Complex, Off Western Express Highway, Goregaon (East Mumbai - 400063, Maharashtra, India. )
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166
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Abstract
Cancer development results from deregulated control of stem cell populations and alterations in their surrounding environment. Notch signaling is an important form of direct cell-cell communication involved in cell fate determination, stem cell potential and lineage commitment. The biological function of this pathway is critically context dependent. Here we review the pro-differentiation role and tumor suppressing function of this pathway, as revealed by loss-of-function in keratinocytes and skin, downstream of p53 and in cross-connection with other determinants of stem cell potential and/or tumor formation, such as p63 and Rho/CDC42 effectors. The possibility that Notch signaling elicits a duality of signals, involved in growth/differentiation control and cell survival will be discussed, in the context of novel approaches for cancer therapy.
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Affiliation(s)
- G P Dotto
- Department of Biochemistry, Lausanne University, Epalinges, Switzerland.
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167
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Danilova N, Sakamoto KM, Lin S. p53 family in development. Mech Dev 2008; 125:919-31. [PMID: 18835440 DOI: 10.1016/j.mod.2008.09.003] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2008] [Revised: 09/04/2008] [Accepted: 09/12/2008] [Indexed: 12/17/2022]
Abstract
The p53 family network is a unique cellular processor that integrates information from various pathways and determines cellular choices between proliferation, replication arrest/repair, differentiation, senescence, or apoptosis. The most studied role of the p53 family is the regulation of stress response and tumor suppression. By removing damaged cells from the proliferating pool, p53 family members preserve the integrity of the genome. In addition to this well recognized role, recent data implicate the p53 protein family in a broader role of controlling cell proliferation, differentiation and death. Members of the p53 protein family with opposing activity perform coordination of these processes. Imbalance of p53 protein family may contribute to a significant proportion of congenital developmental abnormalities in humans.
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Affiliation(s)
- Nadia Danilova
- Department of Molecular, Cell & Developmental Biology, University of California, Los Angeles, 615 Charles E. Young Drive South, BSRB 454, Los Angeles, CA 90095-1606, USA.
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168
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Xu Q, Yuan X, Liu G, Black KL, Yu JS. Hedgehog signaling regulates brain tumor-initiating cell proliferation and portends shorter survival for patients with PTEN-coexpressing glioblastomas. Stem Cells 2008; 26:3018-26. [PMID: 18787206 DOI: 10.1634/stemcells.2008-0459] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The identification of brain tumor stem-like cells (BTSCs) has implicated a role of biological self-renewal mechanisms in clinical brain tumor initiation and propagation. The molecular mechanisms underlying the tumor-forming capacity of BTSCs, however, remain unknown. Here, we have generated molecular signatures of glioblastoma multiforme (GBM) using gene expression profiles of BTSCs and have identified both Sonic Hedgehog (SHH) signaling-dependent and -independent BTSCs and their respective glioblastoma surgical specimens. BTSC proliferation could be abrogated in a pathway-dependent fashion in vitro and in an intracranial tumor model in athymic mice. Both SHH-dependent and -independent brain tumor growth required phosphoinositide 3-kinase-mammalian target of rapamycin signaling. In human GBMs, the levels of SHH and PTCH1 expression were significantly higher in PTEN-expressing tumors than in PTEN-deficient tumors. In addition, we show that hyperactive SHH-GLI signaling in PTEN-coexpressing human GBM is associated with reduced survival time. Thus, distinct proliferation signaling dependence may underpin glioblastoma propagation by BTSCs. Modeling these BTSC proliferation mechanisms may provide a rationale for individualized glioblastoma treatment.
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Affiliation(s)
- Qijin Xu
- Maxine Dunitz Neurosurgical Institute, Department of Neurosurgery, Cedars-Sinai Medical Center, Los Angeles, California 90049, USA
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169
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Activation of p53 stimulates proteasome-dependent truncation of eIF4E-binding protein 1 (4E-BP1). Biol Cell 2008; 100:279-89. [PMID: 18021075 DOI: 10.1042/bc20070121] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND INFORMATION The translational inhibitor protein 4E-BP1 [eIF4E (eukaryotic initiation factor 4E)-binding protein 1] regulates the availability of polypeptide chain initiation factor eIF4E for protein synthesis. Initiation factor eIF4E binds the 5' cap structure present on all cellular mRNAs. Its ability to associate with initiation factors eIF4G and eIF4A, forming the eIF4F complex, brings the mRNA to the 43S complex during the initiation of translation. Binding of eIF4E to eIF4G is inhibited in a competitive manner by 4E-BP1. Phosphorylation of 4E-BP1 decreases the affinity of this protein for eIF4E, thus favouring the binding of eIF4G and enhancing translation. We have previously shown that induction or activation of the tumour suppressor protein p53 rapidly leads to 4E-BP1 dephosphorylation, resulting in sequestration of eIF4E, decreased formation of the eIF4F complex and inhibition of protein synthesis. RESULTS We now report that activation of p53 also results in modification of 4E-BP1 to a truncated form. Unlike full-length 4E-BP1, which is reversibly phosphorylated at multiple sites, the truncated protein is almost completely unphosphorylated. Moreover, the latter interacts with eIF4E in preference to full-length 4E-BP1. Inhibitor studies indicate that the p53-induced cleavage of 4E-BP1 is mediated by the proteasome and is blocked by conditions that inhibit the dephosphorylation of full-length 4E-BP1. Measurements of the turnover of 4E-BP1 indicate that the truncated form is much more stable than the full-length protein. CONCLUSIONS The results suggest a model in which proteasome activity gives rise to a stable, hypophosphorylated and truncated form of 4E-BP1, which may exert a long-term inhibitory effect on the availability of eIF4E, thus contributing to the inhibition of protein synthesis and the growth-inhibitory and pro-apoptotic effects of p53.
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170
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The COX-2 selective inhibitor-independent COX-2 effect on colon carcinoma cells is associated with the Delta1/Notch1 pathway. Dig Dis Sci 2008; 53:2195-203. [PMID: 18320325 DOI: 10.1007/s10620-007-0139-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2006] [Accepted: 11/24/2007] [Indexed: 12/27/2022]
Abstract
BACKGROUND Cyclooxygenase-2 (COX-2) is a key factor in the development of colorectal cancer, and non-steroidal anti-inflammatory drugs (NSAIDs) have anti-colorectal cancer activity. However, the potential molecular mechanism of the COX-2 selective inhibitor effect on proliferation and apoptosis of colon cancer cells is unclear. In this study, we have demonstrated for the first time that the Delta1/Notch1 signal transduction pathway mediates the COX-2 selective inhibitor effect on colorectal cancer cells, and we reveal the mechanism of the Notch1 pathway in terms of regulating the proliferation and apoptosis of colorectal cancer cells. METHODS AND RESULT Colon cancer cell lines HT-29 and SW480 were treated with NS-398 (a COX-2 selective inhibitor) and DAPT (a gamma-secretase inhibitor). The colormetric MTT cell proliferation assay and flow cytometry were used to measure cell proliferation and apoptosis. Reverse transcriptase (RT)-PCR and ELISA analyses were used to detect the levels of COX-2 mRNA expression and prostaglandin E2 (PGE2) concentration from the two cell lines, respectively. The expression of the Notch1, Delta1, ICN, Hes1 and NF-kappaB2 proteins was measured by Western blot. Immunohistochemistry results showed that Notch1 was expressed mainly in the cytoplasm and ICN mainly in the nucleus. COX-2 mRNA was highly expressed in HT-29 cells but not in SW480 cells. Both COX-2 mRNA expression and PGE2 concentration decreased in HT-29 cells treated with NS-398; however, PGE2 levels did not change in SW480 cells treated with NS-398. NS-398 and DAPT inhibited cell proliferation and induced apoptosis in a dose time-dependent manner accompanied by significantly decreased Notch1 activity (P < 0.01), and resulted in a significant down-regulation of Hes1 and NF-kappaB2 (P < 0.01). CONCLUSIONS Our results show that the selective COX-2 inhibitor may inhibit the proliferation and induce apoptosis in colon cancer cells through the COX-2-dependent pathway (HT-29) by decreasing the COX-2 mRNA/PGE2 levels and the activity of the COX-2-independent pathway (SW480). The Notch1 signal pathway mediates the effects of the COX-2 inhibitor on the proliferation and apoptosis of colon cancer cells. This may be a new target of the selective COX-2 inhibitor effect on colon cancer.
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171
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Heinonen H, Nieminen A, Saarela M, Kallioniemi A, Klefström J, Hautaniemi S, Monni O. Deciphering downstream gene targets of PI3K/mTOR/p70S6K pathway in breast cancer. BMC Genomics 2008; 9:348. [PMID: 18652687 PMCID: PMC2496917 DOI: 10.1186/1471-2164-9-348] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2007] [Accepted: 07/24/2008] [Indexed: 12/11/2022] Open
Abstract
Background The 70 kDa ribosomal protein S6 kinase (RPS6KB1), located at 17q23, is amplified and overexpressed in 10–30% of primary breast cancers and breast cancer cell lines. p70S6K is a serine/threonine kinase regulated by PI3K/mTOR pathway, which plays a crucial role in control of cell cycle, growth and survival. Our aim was to determine p70S6K and PI3K/mTOR/p70S6K pathway dependent gene expression profiles by microarrays using five breast cancer cell lines with predefined gene copy number and gene expression alterations. The p70S6K dependent profiles were determined by siRNA silencing of RPS6KB1 in two breast cancer cell lines overexpressing p70S6K. These profiles were further correlated with gene expression alterations caused by inhibition of PI3K/mTOR pathway with PI3K inhibitor Ly294002 or mTOR inhibitor rapamycin. Results Altogether, the silencing of p70S6K altered the expression of 109 and 173 genes in two breast cancer cell lines and 67 genes were altered in both cell lines in addition to RPS6KB1. Furthermore, 17 genes including VTCN1 and CDKN2B showed overlap with genes differentially expressed after PI3K or mTOR inhibition. The gene expression signatures responsive to both PI3K/mTOR pathway and p70S6K inhibitions revealed previously unidentified genes suggesting novel downstream targets for PI3K/mTOR/p70S6K pathway. Conclusion Since p70S6K overexpression is associated with aggressive disease and poor prognosis of breast cancer patients, the potential downstream targets of p70S6K and the whole PI3K/mTOR/p70S6K pathway identified in our study may have diagnostic value.
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Affiliation(s)
- Henna Heinonen
- Institute of Biomedicine and Biomedicum Biochip Center, Genome-Scale Biology Research Program, University of Helsinki, Finland.
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172
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Abstract
The Notch family of transmembrane receptors are important mediators of cell fate determination. Accordingly, Notch signaling is intimately involved in the development of numerous tissues. Recent findings have highlighted a critical role for Notch signaling in normal prostate development. Notch signaling is required for embryonic and postnatal prostatic growth and development, for proper cell lineage specification within the prostate, as well as for adult prostate maintenance and regeneration following castration and hormone replacement. Evidence for Notch as a regulator of prostate cancer development, progression, and metastasis has also emerged. This review summarizes our current understanding of the role of Notch pathway elements, including members of the Jagged, Delta-like, hairy/enhancer-of-split, and hairy/enhancer-of-split related with YRPW motif families, in prostate development and tumorigenesis. Data supporting Notch pathway elements as oncogenes and tumor suppressors in prostate tumors, as well as data implicating Notch receptors and ligands as potential markers of normal prostate stem/progenitor cells and prostate cancer stem/initiating cells, are also presented.
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Affiliation(s)
- Kevin G Leong
- Department of Molecular Biology, Genentech Inc., 1 DNA Way Southern San Francisco, CA 94080, USA
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173
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Abstract
Cellular heterogeneity in cancer was observed decades ago by studies in mice which showed that distinct subpopulations of cells within a tumor mass are capable of driving tumorigenesis. Conceptualized from this finding was the stem-cell hypothesis for cancer, which suggests that only a specific subset of cancer cells within each tumor is responsible for tumor initiation and propagation, termed tumor initiating cells or cancer stem cells (CSCs). Recent data has been provided to support the existence of CSCs in human blood cell-derived cancers and solid organ tumors of the breast, brain, prostate, colon, and skin. Study of human pancreatic cancers has also revealed a specific subpopulation of cancer cells that possess the characteristics of CSCs. These pancreatic cancer stem cells express the cell surface markers CD44, CD24, and epithelial-specific antigen, and represent 0.5% to 1.0% of all pancreatic cancer cells. Along with the properties of self-renewal and multilineage differentiation, pancreatic CSCs display upregulation of important developmental genes that maintain self-renewal in normal stem cells, including Sonic hedgehog (SHH) and BMI-1. Signaling cascades that are integral in tumor metastasis are also upregulated in the pancreatic CSC. Understanding the biologic behavior and the molecular pathways that regulate growth, survival, and metastasis of pancreatic CSCs will help to identify novel therapeutic approaches to treat this dismal disease.
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Affiliation(s)
- Cheong J Lee
- Department of Surgery, University of Michigan, Ann Arbor, MI 48109, USA
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174
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Cardoso BA, Gírio A, Henriques C, Martins LR, Santos C, Silva A, Barata JT. Aberrant signaling in T-cell acute lymphoblastic leukemia: biological and therapeutic implications. ACTA ACUST UNITED AC 2008; 41:344-50. [PMID: 18488097 DOI: 10.1590/s0100-879x2008005000016] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2007] [Accepted: 03/31/2008] [Indexed: 02/14/2023]
Abstract
T-cell acute lymphoblastic leukemia (T-ALL) is a biologically heterogeneous disease with respect to phenotype, gene expression profile and activation of particular intracellular signaling pathways. Despite very significant improvements, current therapeutic regimens still fail to cure a portion of the patients and frequently implicate the use of aggressive protocols with long-term side effects. In this review, we focused on how deregulation of critical signaling pathways, in particular Notch, PI3K/Akt, MAPK, Jak/STAT and TGF-beta, may contribute to T-ALL. Identifying the alterations that affect intracellular pathways that regulate cell cycle and apoptosis is essential to understanding the biology of this malignancy, to define more effective markers for the correct stratification of patients into appropriate therapeutic regimens and to identify novel targets for the development of specific, less detrimental therapies for T-ALL.
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Affiliation(s)
- B A Cardoso
- Unidade de Biologia do Cancro, Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
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175
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The FoxO3a gene is a key negative target of canonical Notch signalling in the keratinocyte UVB response. EMBO J 2008; 27:1243-54. [PMID: 18388864 DOI: 10.1038/emboj.2008.45] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2007] [Accepted: 12/17/2007] [Indexed: 11/08/2022] Open
Abstract
Notch signalling has an important role in skin homeostasis, promoting keratinocyte differentiation and suppressing tumorigenesis. Here we show that this pathway also has an essential anti-apoptotic function in the keratinocyte UVB response. Notch1 expression and activity are significantly induced, in a p53-dependent manner, by UVB exposure of primary keratinocytes as well as intact epidermis of both mouse and human origin. The apoptotic response to UVB is increased by deletion of the Notch1 gene or down-modulation of Notch signalling by pharmacological inhibition or genetic suppression of 'canonical' Notch/CSL/MAML1-dependent transcription. Conversely, Notch activation protects keratinocytes against apoptosis through a mechanism that is not linked to Notch-induced cell cycle withdrawal or NF-kappaB activation. Rather, transcription of FoxO3a, a key pro-apoptotic gene, is under direct negative control of Notch/HERP transcription in keratinocytes, and upregulation of this gene accounts for the increased susceptibility to UVB of cells with suppressed Notch signalling. Thus, the canonical Notch/HERP pathway functions as a protective anti-apoptotic mechanism in keratinocytes through negative control of FoxO3a expression.
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176
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Gude NA, Emmanuel G, Wu W, Cottage CT, Fischer K, Quijada P, Muraski JA, Alvarez R, Rubio M, Schaefer E, Sussman MA. Activation of Notch-mediated protective signaling in the myocardium. Circ Res 2008; 102:1025-35. [PMID: 18369158 DOI: 10.1161/circresaha.107.164749] [Citation(s) in RCA: 147] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The Notch network regulates multiple cellular processes, including cell fate determination, development, differentiation, proliferation, apoptosis, and regeneration. These processes are regulated via Notch-mediated activity that involves hepatocyte growth factor (HGF)/c-Met receptor and phosphatidylinositol 3-kinase/Akt signaling cascades. The impact of HGF on Notch signaling was assessed following myocardial infarction as well as in cultured cardiomyocytes. Notch1 is activated in border zone cardiomyocytes coincident with nuclear c-Met following infarction. Intramyocardial injection of HGF enhances Notch1 and Akt activation in adult mouse myocardium. Corroborating evidence in cultured cardiomyocytes shows treatment with HGF or insulin increases levels of Notch effector Hes1 in immunoblots, whereas overexpression of activated Notch intracellular domain prompts a 3-fold increase in phosphorylated Akt. Infarcted hearts injected with adenoviral vector expressing Notch intracellular domain treatment exhibit improved hemodynamic function in comparison with control mice after 4 weeks, implicating Notch signaling in a cardioprotective role following cardiac injury. These results indicate Notch activation in cardiomyocytes is mediated through c-Met and Akt survival signaling pathways, and Notch1 signaling in turn enhances Akt activity. This mutually supportive crosstalk suggests a positive survival feedback mechanism between Notch and Akt signaling in adult myocardium following injury.
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Affiliation(s)
- Natalie A Gude
- San Diego State University Heart Institute, Department of Biology, San Diego State University, San Diego, CA 92182, USA
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177
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Narayana Y, Balaji KN. NOTCH1 up-regulation and signaling involved in Mycobacterium bovis BCG-induced SOCS3 expression in macrophages. J Biol Chem 2008; 283:12501-11. [PMID: 18332140 DOI: 10.1074/jbc.m709960200] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Suppressor of cytokine signaling (SOCS) 3 is a critical negative regulator of cytokine signaling and is induced by Mycobacterium bovis Bacille Calmette-Guérin (M. bovis BCG) in mouse macrophages. However, little is known about the early receptor proximal signaling mechanisms underlying mycobacteria-mediated induction of SOCS3. We demonstrate here for the first time that M. bovis BCG up-regulates NOTCH1 and activates the NOTCH1 signaling pathway, leading to the expression of SOCS3. We show that perturbing Notch signaling in infected macrophages results in the marked reduction in the expression of SOCS3. Furthermore, enforced expression of the Notch1 intracellular domain in RAW 264.7 macrophages induces the expression of SOCS3, which can be further potentiated by M. bovis BCG. The perturbation of Toll-like receptor (TLR) 2 signaling resulted in marked reduction in SOCS3 levels and expression of the NOTCH1 target gene, Hes1. The down-regulation of MyD88 resulted in a significant decrease in SOCS3 expression, implicating the role of the TLR2-MyD88 axis in M. bovis BCG-triggered signaling. However, the SOCS3 inducing ability of M. bovis BCG remains unaltered also upon infection of macrophages from TLR4-defective C3H/HeJ mice. More importantly, signaling perturbation data suggest the involvement of cross-talk among members of the phosphoinositide 3-kinase and mitogen-activated protein kinase cascades with NOTCH1 signaling in SOCS3 expression. Furthermore, SOCS3 expression requires the NOTCH1-mediated recruitment of Suppressor of Hairless (CSL) and nuclear factor-kappaB to the Socs3 promoter. Overall, these results implicate NOTCH1 signaling during inducible expression of SOCS3 following infection of macrophages with an intracellular bacillus-like M. bovis BCG.
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Affiliation(s)
- Yeddula Narayana
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
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178
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The Notch pathway in podocytes plays a role in the development of glomerular disease. Nat Med 2008; 14:290-8. [DOI: 10.1038/nm1731] [Citation(s) in RCA: 318] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2007] [Accepted: 01/25/2008] [Indexed: 12/20/2022]
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179
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Abstract
The mammalian target of rapamycin mTOR is a central element in an evolutionary conserved signalling pathway that regulates cell growth, survival and proliferation, orchestrating signals originating from growth factors, nutrients or particular stress stimuli. Two important modulators of mTOR activity are the AKT and ERK/MAPK signalling pathways. Many studies have shown that mTOR plays an important role in the biology of malignant cells, including deregulation of the cell cycle, inactivation of apoptotic machinery and resistance to chemotherapeutic agents. The development of several mTOR inhibitors, in addition to rapamycin, has facilitated studies of the role of mTOR in cancer, and verified the antitumour effect of mTOR inhibition in many types of neoplasms, including lymphomas. Clinical trials of rapamycin derivatives in lymphoma patients are already in development and there are encouraging preliminary results, such as the substantial response of a subset of mantle cell lymphoma patients to the rapamycin analogue temsirolimus. Based on results obtained from in vitro and in vivo studies of the mTOR pathway in lymphomas, it seems that better understanding of mTOR regulation will reveal aspects of lymphomagenesis and contribute to the development of more powerful, targeted therapies for lymphoma patients.
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180
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Schavinsky-Khrapunsky Y, Priel E, Aboud M. Dose-dependent dual effect of HTLV-1 tax oncoprotein on p53-dependent nucleotide excision repair in human T-cells. Int J Cancer 2008; 122:305-16. [PMID: 17918160 DOI: 10.1002/ijc.23091] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In this study we investigated the effect of Tax on nucleotide excision repair (NER) in human T-cell lines by using the host cell repair analysis of UVC-irradiated reporter plasmid. This analysis revealed a p53-dependent NER activity in wild type (w.t.) p53-containing T-cells and p53-independent NER in w.t. p53-lacking T-cells. Notably, in the w.t. p53-containing cells Tax exerted a dose-dependent dual effect on NER. While low Tax doses markedly stimulated this repair, high Tax doses strongly reduced it. Further experiments demonstrated that the low Tax doses enhanced, in these cells, the level and the transcriptional function of their w.t. p53 protein. On the other hand, although the high Tax doses further increased the level of p53, they functionally inactivated its accumulating molecules. Both of these Tax effects on p53 proved to be mediated by Tax-induced NF-kappaB-related mechanisms. Together, these data suggest that by NF-kappaB activation Tax elevates the level of the cellular w.t. p53. However, while at low Tax doses the elevating w.t. p53 molecules are functionally active and capable of stimulating NER, intensifying further the NF-kappaB activation by the high Tax doses concomitantly evokes certain mechanism(s) which functionally inactivates the accumulating p53 protein. In contrast to this dual effect on the p53-dependent NER, Tax displayed only an inhibitory effect on the p53-independent NER by its high doses, whereas its low doses had no effect on this repair. The mechanisms of the NF-kappaB-associated effects on the level and function of the cellular w.t.p53 and of the p53-independent NER noted in our experimental systems are further investigated in our laboratory.
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Affiliation(s)
- Yana Schavinsky-Khrapunsky
- The Shraga Segal Department of Microbiology and Immunology, Faculty of Health Sciences and Cancer Research Center, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
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181
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Hajdu M, Luttun A, Pelacho B, Burns TC, Chase L, Gutiérrez-Pérez M, Jiang Y, Lenvik T, Vas V, Uher F, Sebestyén A, Verfaillie C. Transcriptional characterization of the notch signaling pathway in rodent multipotent adult progenitor cells. Pathol Oncol Res 2007; 13:302-10. [DOI: 10.1007/bf02940309] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2007] [Accepted: 12/05/2007] [Indexed: 12/16/2022]
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182
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Henning K, Heering J, Schwanbeck R, Schroeder T, Helmbold H, Schäfer H, Deppert W, Kim E, Just U. Notch1 activation reduces proliferation in the multipotent hematopoietic progenitor cell line FDCP-mix through a p53-dependent pathway but Notch1 effects on myeloid and erythroid differentiation are independent of p53. Cell Death Differ 2007; 15:398-407. [PMID: 18049480 DOI: 10.1038/sj.cdd.4402277] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Signaling mediated by activation of the transmembrane receptor Notch influences cell-fate decisions, differentiation, proliferation, and cell survival. Activated Notch reduces proliferation by altering cell-cycle kinetics and promotes differentiation in hematopoietic progenitor cells. Here, we investigated if the G(1) arrest and differentiation induced by activated mNotch1 are dependent on tumor suppressor p53, a critical mediator of cellular growth arrest. Multipotent wild-type p53-expressing (p53(wt)) and p53-deficient (p53(null)) hematopoietic progenitor cell lines (FDCP-mix) carrying an inducible mNotch1 system were used to investigate the effects of proliferation and differentiation upon mNotch1 signaling. While activated Notch reduced proliferation of p53(wt)-cells, no change was observed in p53(null)-cells. Activated Notch upregulated the p53 target p21(cip/waf) in p53(wt)-cells, but not in p53(null)-cells. Induction of the p21(cip/waf) gene by activated Notch was mediated by increased binding of p53 to p53-binding sites in the p21(cip/waf) promoter and was independent of the canonical RBP-J binding site. Re-expression of p53(wt) in p53(null) cells restored the inhibition of proliferation by activated Notch. Thus, activated Notch inhibits proliferation of multipotent hematopoietic progenitor cells via a p53-dependent pathway. In contrast, myeloid and erythroid differentiation was similarly induced in p53(wt) and p53(null) cells. These data suggest that Notch signaling triggers two distinct pathways, a p53-dependent one leading to a block in proliferation and a p53-independent one promoting differentiation.
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Affiliation(s)
- K Henning
- Department of Biochemistry, Christian-Albrechts-University of Kiel, Olshausenstrasse 40, Kiel, Germany
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183
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Leong KG, Niessen K, Kulic I, Raouf A, Eaves C, Pollet I, Karsan A. Jagged1-mediated Notch activation induces epithelial-to-mesenchymal transition through Slug-induced repression of E-cadherin. ACTA ACUST UNITED AC 2007; 204:2935-48. [PMID: 17984306 PMCID: PMC2118507 DOI: 10.1084/jem.20071082] [Citation(s) in RCA: 372] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Aberrant expression of Jagged1 and Notch1 are associated with poor outcome in breast cancer. However, the reason that Jagged1 and/or Notch overexpression portends a poor prognosis is unknown. We identify Slug, a transcriptional repressor, as a novel Notch target and show that elevated levels of Slug correlate with increased expression of Jagged1 in various human cancers. Slug was essential for Notch-mediated repression of E-cadherin, which resulted in beta-catenin activation and resistance to anoikis. Inhibition of ligand-induced Notch signaling in xenografted Slug-positive/E-cadherin-negative breast tumors promoted apoptosis and inhibited tumor growth and metastasis. This response was associated with down-regulated Slug expression, reexpression of E-cadherin, and suppression of active beta-catenin. Our findings suggest that ligand-induced Notch activation, through the induction of Slug, promotes tumor growth and metastasis characterized by epithelial-to-mesenchymal transition and inhibition of anoikis.
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Affiliation(s)
- Kevin G Leong
- Department of Medical Biophysics, British Columbia Cancer Agency, Vancouver, British Columbia V5Z 1L3, Canada
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184
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Anderson LJ, Longnecker R. An auto-regulatory loop for EBV LMP2A involves activation of Notch. Virology 2007; 371:257-66. [PMID: 17980397 DOI: 10.1016/j.virol.2007.10.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2007] [Revised: 06/25/2007] [Accepted: 10/10/2007] [Indexed: 12/11/2022]
Abstract
LMP2A is consistently detected in Hodgkin's lymphoma, nasopharyngeal carcinoma and has also been detected in Burkitt's lymphoma. Interestingly, LMP2A is detected in the absence of the transcriptional activator EBNA2, suggesting that an alternative mechanism is responsible for LMP2A expression. The intracellular domain of Notch (Notch-IC) and EBNA2 are functional homologs and recent microarray analysis indicates that LMP2A may constitutively activate the Notch pathway in vivo. Coupled with evidence that Notch-IC can bind to and activate the LMP2A promoter, we hypothesized that expression of LMP2A results in the constitutive activation of the Notch pathway to auto-regulate its promoter. Our data indicate that LMP2A constitutively activates the Notch pathway in B cells and epithelial cells. Expression of LMP2A alone is sufficient to activate its own expression and the amino-terminal signaling domain is required as LMP2B is unable to activate the LMP2A promoter. In addition, point mutations in tyrosines 31, 101 and 112 each results in a significant decrease in LMP2A promoter activation. Deletion of the RBP-Jkappa consensus sequences results in a significant decrease in promoter activity. The observation that LMP2A activates its own promoter suggests that LMP2A exploits the Notch pathway in order to control its own expression and may explain EBNA2-independent expression of LMP2A in EBV-associated malignancies.
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Affiliation(s)
- Leah J Anderson
- Department of Microbiology and Immunology, Northwestern University, Chicago, Illinois 60611, USA
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185
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Cecchinato V, Chiaramonte R, Nizzardo M, Cristofaro B, Basile A, Sherbet GV, Comi P. Resveratrol-induced apoptosis in human T-cell acute lymphoblastic leukaemia MOLT-4 cells. Biochem Pharmacol 2007; 74:1568-74. [PMID: 17868649 DOI: 10.1016/j.bcp.2007.08.001] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2007] [Revised: 07/12/2007] [Accepted: 08/02/2007] [Indexed: 01/18/2023]
Abstract
Resveratrol (RES) is a natural occurring phytoalexin that has been shown to have chemopreventive activity. Resveratrol acts both by suppressing cell proliferation and inducing apoptosis in a variety of cancer cell lines. In this study, we show that RES induces apoptosis in MOLT-4 acute lymphoblastic leukaemia cells by modulating three different pathways that regulate cells survival and cell death. We show for the first time that RES inhibits the survival signalling pathways Notch and their down stream effector and modulates the operation of interacting signalling systems. It induces an increase in the levels of the pro-apoptotic proteins p53, its effector p21waf and Bax. We also show that RES inhibits the PI3K/Akt pathway and activates Gsk-3beta. The data presented here demonstrate unequivocally that RES induces apoptosis by inhibiting the Notch pathway and markedly influencing the operation of the interacting apoptosis pathways mediated by p53 and PI3K/Akt. These data support findings from other laboratories that have suggested the use of RES as a chemopreventive agent. Here, we have identified potential signalling pathways influenced by RES and this could lead to the identification of the targets of RES-induced apoptosis and growth control.
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186
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Alimirah F, Panchanathan R, Davis FJ, Chen J, Choubey D. Restoration of p53 expression in human cancer cell lines upregulates the expression of Notch1: implications for cancer cell fate determination after genotoxic stress. Neoplasia 2007; 9:427-34. [PMID: 17534448 PMCID: PMC1877974 DOI: 10.1593/neo.07211] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2007] [Revised: 04/03/2007] [Accepted: 04/04/2007] [Indexed: 11/18/2022] Open
Abstract
Following genotoxic stress, transcriptional activation of target genes by p53 tumor suppressor is critical in cell fate determination. Here we report that the restoration of p53 function in human cancer cell lines that are deficient in p53 function upregulated the expression of Notch1. Interestingly, the expression of wild-type p53 in human prostate and breast cancer cell lines correlated well with increased expression of Notch1. Furthermore, knockdown of p53 expression in cancer cells that express wild-type p53 resulted in reduced expression of Notch1. Importantly, genotoxic stress to cancer cells that resulted in activation of p53 also upregulated the expression of Notch1. Moreover, p53-mediated induction of Notch1 expression was associated with stimulation of the activity of Notch-responsive reporters. Notably, p53 differentially regulated the expression of Notch family members: expression of Notch2 and Notch4 was not induced by p53. Significantly, treatment of cells with gamma secretase inhibitor, an inhibitor of Notch signaling, increased susceptibility to apoptosis in response to genotoxic stress. Together, our observations suggest that p53-mediated upregulation of Notch1 expression in human cancer cell lines contributes to cell fate determination after genotoxic stress.
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Affiliation(s)
- Fatouma Alimirah
- Edward Hines Jr. VA Hospital, 5th Avenue and Roosevelt Road, Building 1, Mail Code 114B, Hines, IL 60141, USA
| | - Ravichandran Panchanathan
- Department of Radiation Oncology, Loyola University Chicago, 5th Avenue and Roosevelt Road, Building 1, Mail Code 114B, Hines, IL 60141, USA
| | - Francesca J Davis
- Department of Radiation Oncology, Loyola University Chicago, 5th Avenue and Roosevelt Road, Building 1, Mail Code 114B, Hines, IL 60141, USA
| | - Jianming Chen
- Department of Radiation Oncology, Loyola University Chicago, 5th Avenue and Roosevelt Road, Building 1, Mail Code 114B, Hines, IL 60141, USA
| | - Divaker Choubey
- Edward Hines Jr. VA Hospital, 5th Avenue and Roosevelt Road, Building 1, Mail Code 114B, Hines, IL 60141, USA
- Department of Radiation Oncology, Loyola University Chicago, 5th Avenue and Roosevelt Road, Building 1, Mail Code 114B, Hines, IL 60141, USA
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187
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Mendes KN, Nicorici D, Cogdell D, Tabus I, Yli-Harja O, Guerra R, Hamilton SR, Zhang W. Analysis of signaling pathways in 90 cancer cell lines by protein lysate array. J Proteome Res 2007; 6:2753-67. [PMID: 17564428 DOI: 10.1021/pr070184h] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
UNLABELLED Multiple signal transduction pathways play a crucial role in cancer development, progression, and response to different therapies. An important issue is whether common signal transduction pathways are ubiquitously altered in all cancer types and some unique pathways are involved in different cancer types. Another important issue is whether and how transduction signaling molecules are heterogeneously expressed and activated in different cancer cells within and between cancer cell types. METHODS To gain insight into these issues, we assembled a protein lysate array with 90 different cell lines of 12 different cell types. Each sample is diluted 2-fold six times, and samples from the dilution series were printed three times on the array. We then measured the expression levels and phosphorylation status of 52 different signaling proteins with specific antibodies and carried out statistical hierarchical clustering analysis. RESULTS The most significant finding based on the cluster analysis was that the cell lines did not group based on tumor types, suggesting that the signaling pathways studied were commonly activated in most of the tumor types cultured in vitro. As expected, related proteins associated with specific signaling pathways clustered together, and analysis of the 30 most differentially expressed proteins revealed the PI3-K signaling pathway was upregulated in several different tumor types and the VEGF-angiogenesis pathway was downregulated in hematopoetic cancers. Another important observation, with clinical implications was that EGFR was the most heterogeneous among all the cell lines. We also observed signaling pathways unique to specific types of cancers such as the inverse relationship between p16ink and Rb, and the EGFR mediated pathway activation characteristic of pancreatic cancers. CONCLUSIONS Using reverse phase lysate array analysis in this study, we were able to determine potential relationships and signaling pathways, both common and unique, to different types of cancer using cell lines in vitro. This data could be utilized for mining information related to an individual cancer of interest and combined with morphological and genomic profiles would help in creating a combination of expression markers and/or functional signaling maps for specific cancer diagnosis and therapy.
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Affiliation(s)
- Kanchana Natarajan Mendes
- Department of Pathology, the University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA
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188
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Raver-Shapira N, Marciano E, Meiri E, Spector Y, Rosenfeld N, Moskovits N, Bentwich Z, Oren M. Transcriptional activation of miR-34a contributes to p53-mediated apoptosis. Mol Cell 2007; 26:731-43. [PMID: 17540598 DOI: 10.1016/j.molcel.2007.05.017] [Citation(s) in RCA: 1013] [Impact Index Per Article: 59.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2007] [Revised: 05/05/2007] [Accepted: 05/17/2007] [Indexed: 02/07/2023]
Abstract
p53 is a potent tumor suppressor, whose biological effects are largely due to its function as a transcriptional regulator. Here we report that, in addition to regulating the expression of hundreds of protein-coding genes, p53 also modulates the levels of microRNAs (miRNAs). Specifically, p53 can induce expression of microRNA-34a (miR-34a) in cultured cells as well as in irradiated mice, by binding to a perfect p53 binding site located within the gene that gives rise to miR-34a. Processing of the primary transcript into mature miR-34a involves the excision of a 30 kb intron. Notably, inactivation of miR-34a strongly attenuates p53-mediated apoptosis in cells exposed to genotoxic stress, whereas overexpression of miR-34a mildly increases apoptosis. Hence, miR-34a is a direct proapoptotic transcriptional target of p53 that can mediate some of p53's biological effects. Perturbation of miR-34a expression, as occurs in some human cancers, may thus contribute to tumorigenesis by attenuating p53-dependent apoptosis.
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Affiliation(s)
- Nina Raver-Shapira
- Department of Molecular Cell Biology, The Weizmann Institute of Science, Rehovot 76100, Israel
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189
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Abstract
Notch is an evolutionarily conserved local cell signaling mechanism that participates in a variety of cellular processes: cell fate specification, differentiation, proliferation, apoptosis, adhesion, epithelial-mesenchymal transition, migration, and angiogenesis. These processes can be subverted in Notch-mediated pathological situations. In the first part of this review, we will discuss the role of Notch in vertebrate central nervous system development, somitogenesis, cardiovascular and endocrine development, with attention to the mechanisms by which Notch regulates cell fate specification and patterning in these tissues. In the second part, we will review the molecular aspects of Notch-mediated neoplasias, where Notch can act as an oncogene or as a tumor suppressor. From all these studies, it becomes evident that the outcome of Notch signaling is strictly context-dependent and differences in the strength, timing, cell type, and context of the signal may affect the final outcome. It is essential to understand how Notch integrates inputs from other signaling pathways and how specificity is achieved, because this knowledge may be relevant for future therapeutic applications.
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Affiliation(s)
- Victoria Bolós
- Departmento de Inmunología y Oncología, Centro Nacional de Biotecnología/Consejo Superior de Investigaciones Científicas, Darwin 3, Campus de Cantoblanco, E-28049 Madrid, Spain
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190
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Lefort K, Mandinova A, Ostano P, Kolev V, Calpini V, Kolfschoten I, Devgan V, Lieb J, Raffoul W, Hohl D, Neel V, Garlick J, Chiorino G, Dotto GP. Notch1 is a p53 target gene involved in human keratinocyte tumor suppression through negative regulation of ROCK1/2 and MRCKalpha kinases. Genes Dev 2007; 21:562-77. [PMID: 17344417 PMCID: PMC1820898 DOI: 10.1101/gad.1484707] [Citation(s) in RCA: 242] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Little is known about the regulation and function of the Notch1 gene in negative control of human tumors. Here we show that Notch1 gene expression and activity are substantially down-modulated in keratinocyte cancer cell lines and tumors, with expression of this gene being under p53 control in these cells. Genetic suppression of Notch signaling in primary human keratinocytes is sufficient, together with activated ras, to cause aggressive squamous cell carcinoma formation. Similar tumor-promoting effects are also caused by in vivo treatment of mice, grafted with keratinocytes expressing oncogenic ras alone, with a pharmacological inhibitor of endogenous Notch signaling. These effects are linked with a lesser commitment of keratinocytes to differentiation, an expansion of stem cell populations, and a mechanism involving up-regulation of ROCK1/2 and MRCKalpha kinases, two key effectors of small Rho GTPases previously implicated in neoplastic progression. Thus, the Notch1 gene is a p53 target with a role in human tumor suppression through negative regulation of Rho effectors.
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Affiliation(s)
- Karine Lefort
- Department of Biochemistry, University of Lausanne, Epalinges CH-1066, Switzerland
| | - Anna Mandinova
- Cutaneous Biology Research Center, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA
| | - Paola Ostano
- Laboratory of Cancer Pharmacogenomics, Fondo “Edo Tempia,” Biella 13900, Italy
| | - Vihren Kolev
- Cutaneous Biology Research Center, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA
| | - Valerie Calpini
- Department of Biochemistry, University of Lausanne, Epalinges CH-1066, Switzerland
| | - Ingrid Kolfschoten
- Department of Biochemistry, University of Lausanne, Epalinges CH-1066, Switzerland
| | - Vikram Devgan
- Cutaneous Biology Research Center, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA
| | - Jocelyn Lieb
- Cutaneous Biology Research Center, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA
| | - Wassim Raffoul
- Department of Surgery, Centre Hospitalier Universitaire Vaudois, Lausanne CH-1011, Switzerland
| | - Daniel Hohl
- Department of Dermatology, Centre Hospitalier Universitaire Vaudois, Lausanne CH-1011, Switzerland
| | - Victor Neel
- Department of Dermatology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
| | - Jonathan Garlick
- Division of Cancer Biology and Tissue Engineering, Tufts University Dental School, Boston, Massachusetts 02111, USA
| | - Giovanna Chiorino
- Laboratory of Cancer Pharmacogenomics, Fondo “Edo Tempia,” Biella 13900, Italy
| | - G. Paolo Dotto
- Department of Biochemistry, University of Lausanne, Epalinges CH-1066, Switzerland
- Cutaneous Biology Research Center, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA
- Corresponding author.E-MAIL ; FAX 41-21-692-5705
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191
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Liu WH, Hsiao HW, Tsou WI, Lai MZ. Notch inhibits apoptosis by direct interference with XIAP ubiquitination and degradation. EMBO J 2007; 26:1660-9. [PMID: 17318174 PMCID: PMC1829378 DOI: 10.1038/sj.emboj.7601611] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2006] [Accepted: 01/25/2007] [Indexed: 01/15/2023] Open
Abstract
The physiological activity of Notch is a function of its ability to increase survival in many cell types. Several pathways have been shown to contribute to the survival effect of Notch, but the exact mechanism of Notch action is not completely understood. Here we identified that the regulation of cell survival by Notch intracellular domain could partly be attributed to a selective increase of X-linked inhibitor of apoptosis protein (XIAP). We further found that Notch intracellular domain inhibited the degradation of XIAP during apoptosis. The transactivation domain of Notch interacted directly with the RING region of XIAP to block the binding of E2 and prevent the in vivo and in vitro ubiquitination of XIAP. This antiapoptotic activity of Notch was abolished when XIAP was knocked down. Our results reveal a novel mechanism for Notch-selective suppression of apoptosis through an increase in the stability of a key antiapoptotic protein, XIAP.
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Affiliation(s)
- Wen-Hsien Liu
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan, ROC
| | - Huey-Wen Hsiao
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan, ROC
- Graduate Institute of Microbiology and Immunology, National Yang-Ming University, Taipei, Taiwan, ROC
| | - Wen-I Tsou
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan, ROC
| | - Ming-Zong Lai
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan, ROC
- Graduate Institute of Microbiology and Immunology, National Yang-Ming University, Taipei, Taiwan, ROC
- Graduate Institute of Immunology, National Taiwan University, Taipei, Taiwan, ROC
- Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan, ROC. Tel.: +886 2 2789 9236; Fax: +886 2 2782 6085; E-mail:
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192
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Kim SB, Chae GW, Lee J, Park J, Tak H, Chung JH, Park TG, Ahn JK, Joe CO. Activated Notch1 interacts with p53 to inhibit its phosphorylation and transactivation. Cell Death Differ 2006; 14:982-91. [PMID: 17186020 DOI: 10.1038/sj.cdd.4402083] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
We propose a biochemical mechanism for the negative role of Notch signaling on p53 transactivation function. Expression of the intracellular domain of human Notch1 (Notch1-IC) inhibits the expression of p53-responsive genes p21, mdm2, and bax in HCT116 p53(-/-) cells. Furthermore, Notch1-IC expression inhibits the phosphorylation of ectopically expressed p53 in HCT116 p53(-/-) cells as well as the phosphorylation of endogenous p53 in UV-treated HCT116 p53(+/+) cells. Transcriptional downregulation of p53-responsive genes by Notch1-IC was confirmed both by chromatin immunoprecipitation assay and Northern blot analysis. We found the intracellular interaction between Notch1-IC and p53 in HCT116 p53(+/+) cells and suggest that activated Notch1 interaction with p53 is an important cellular event for the inhibition of p53-dependent transactivation. The N-terminal fragment of Notch1-IC, which can interacts with p53, inhibits p53 phosphorylation and represses p53 transactivation. In addition, Notch signaling downregulated p53-dependent apoptosis induced by UV irradiation.
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Affiliation(s)
- S B Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
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193
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Roy M, Pear WS, Aster JC. The multifaceted role of Notch in cancer. Curr Opin Genet Dev 2006; 17:52-9. [PMID: 17178457 DOI: 10.1016/j.gde.2006.12.001] [Citation(s) in RCA: 233] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2006] [Accepted: 12/11/2006] [Indexed: 12/11/2022]
Abstract
The diverse roles that Notch signals play during the development and maintenance of normal tissues are recapitulated in different forms of cancer. Depending on the tumor type, Notch can variously promote or limit tumor growth through either cell autonomous or cell non-autonomous effects on differentiation, cellular metabolism, cell cycle progression, angiogenesis, and possibly self-renewal and immune function. Of particular interest, recent findings indicate that a high fraction of T-cell acute lymphoblastic leukemias and lymphomas have activating mutations in the Notch 1 receptor, and that Notch signaling might have a role in the maintenance of normal and malignant stem cells.
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Affiliation(s)
- Monideepa Roy
- Department of Pathology, Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, USA
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194
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Abstract
Control of mRNA translation plays a fundamental role in many aspects of cell metabolism. It constitutes a critical step in the control of gene expression, and consequently cell growth, proliferation and differentiation. Translation is regulated in response to nutrient availability, hormones, mitogenic and growth factor stimulation and is coupled with cell cycle progression and cell growth. Signaling by the PI3K/Akt/mTOR pathway profoundly affects mRNA translation through phosphorylation of downstream targets such as 4E-BP and S6K. Inhibitors of this pathway and thus cap-dependent translation are emerging as promising therapeutic options for the treatment of cancer.
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Affiliation(s)
- Y Mamane
- Department of Biochemistry, McGill Cancer Centre, McGill University, Montreal, Quebec, Canada
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195
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Constantinou C, Clemens MJ. Regulation of translation factors eIF4GI and 4E-BP1 during recovery of protein synthesis from inhibition by p53. Cell Death Differ 2006; 14:576-85. [PMID: 16990847 DOI: 10.1038/sj.cdd.4402045] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Activation of the tumour suppressor protein p53 rapidly inhibits protein synthesis. This is associated with dephosphorylation and cleavage of initiation factor eIF4GI and the eIF4E-binding protein 4E-BP1. When the activation of p53 is reversed within 16 h 4E-BP1 becomes rephosphorylated, the level of intact eIF4GI slowly increases and protein synthesis gradually recovers. The recovery of protein synthesis is partially blocked by rapamycin and wortmannin but not by the protein kinase inhibitors PD98059 and CGP74514A. Both rapamycin and wortmannin, but not PD98059 or CGP74514A, delay the reappearance of eIF4GI. In contrast, full-length 4E-BP1 rapidly becomes rephosphorylated and this process is partially inhibited by rapamycin, PD98059 and CGP74514A. Thus, activation of p53 results in the inhibition of distinct rapamycin- and wortmannin-sensitive pathways that target eIF4GI, and rapamycin-sensitive and -insensitive pathways that target 4E-BP1. Following inactivation of p53 the gradual recovery is determined largely by the kinetics of restoration of eIF4GI rather than by the rephosphorylation of full-length 4E-BP1. These findings suggest that the ability of cells to rephosphorylate 4E-BP1, resynthesise eIF4GI and restore the rate of protein synthesis after inactivation of p53 is an important aspect of recovery following the relief of physiological stress.
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Affiliation(s)
- C Constantinou
- Translational Control Group, Centre for Molecular and Metabolic Signalling, Division of Basic Medical Sciences, St George's, University of London, Cranmer Terrace, London SW17 0RE, UK
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196
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Abstract
The Notch signaling pathway is among the most commonly used communication channels in animal cells. Recent studies have demonstrated that this pathway is indispensable for cells in various stages of maturation, including terminal differentiation. One main focus in mammalian studies is the role of Notch in embryonic and postembryonic stem cell systems. In this review, the roles of Notch signaling in various mammalian stem and early progenitor cells are summarized.
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Affiliation(s)
- Shigeru Chiba
- Department of Cell Therapy and Transplantation Medicine, University of Tokyo, 7-3-1 Hongo, Tokyo 113-8655, Japan.
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