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Kim WR, Park EG, Lee YJ, Bae WH, Lee DH, Kim HS. Integration of TE Induces Cancer Specific Alternative Splicing Events. Int J Mol Sci 2022; 23:ijms231810918. [PMID: 36142830 PMCID: PMC9502224 DOI: 10.3390/ijms231810918] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 09/13/2022] [Accepted: 09/13/2022] [Indexed: 11/16/2022] Open
Abstract
Alternative splicing of messenger RNA (mRNA) precursors contributes to genetic diversity by generating structurally and functionally distinct transcripts. In a disease state, alternative splicing promotes incidence and development of several cancer types through regulation of cancer-related biological processes. Transposable elements (TEs), having the genetic ability to jump to other regions of the genome, can bring about alternative splicing events in cancer. TEs can integrate into the genome, mostly in the intronic regions, and induce cancer-specific alternative splicing by adjusting various mechanisms, such as exonization, providing splicing donor/acceptor sites, alternative regulatory sequences or stop codons, and driving exon disruption or epigenetic regulation. Moreover, TEs can produce microRNAs (miRNAs) that control the proportion of transcripts by repressing translation or stimulating the degradation of transcripts at the post-transcriptional level. Notably, TE insertion creates a cancer-friendly environment by controlling the overall process of gene expression before and after transcription in cancer cells. This review emphasizes the correlative interaction between alternative splicing by TE integration and cancer-associated biological processes, suggesting a macroscopic mechanism controlling alternative splicing by TE insertion in cancer.
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Affiliation(s)
- Woo Ryung Kim
- Department of Integrated Biological Sciences, Pusan National University, Busan 46241, Korea
- Institute of Systems Biology, Pusan National University, Busan 46241, Korea
| | - Eun Gyung Park
- Department of Integrated Biological Sciences, Pusan National University, Busan 46241, Korea
- Institute of Systems Biology, Pusan National University, Busan 46241, Korea
| | - Yun Ju Lee
- Department of Integrated Biological Sciences, Pusan National University, Busan 46241, Korea
- Institute of Systems Biology, Pusan National University, Busan 46241, Korea
| | - Woo Hyeon Bae
- Department of Integrated Biological Sciences, Pusan National University, Busan 46241, Korea
- Institute of Systems Biology, Pusan National University, Busan 46241, Korea
| | - Du Hyeong Lee
- Department of Integrated Biological Sciences, Pusan National University, Busan 46241, Korea
- Institute of Systems Biology, Pusan National University, Busan 46241, Korea
| | - Heui-Soo Kim
- Institute of Systems Biology, Pusan National University, Busan 46241, Korea
- Department of Biological Sciences, College of Natural Sciences, Pusan National University, Busan 46241, Korea
- Correspondence:
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Urbanski L, Leclair N, Anczuków O. Alternative-splicing defects in cancer: Splicing regulators and their downstream targets, guiding the way to novel cancer therapeutics. Wiley Interdiscip Rev RNA 2018; 9:e1476. [PMID: 29693319 PMCID: PMC6002934 DOI: 10.1002/wrna.1476] [Citation(s) in RCA: 205] [Impact Index Per Article: 34.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 02/27/2018] [Accepted: 03/01/2018] [Indexed: 12/14/2022]
Abstract
Defects in alternative splicing are frequently found in human tumors and result either from mutations in splicing-regulatory elements of specific cancer genes or from changes in the regulatory splicing machinery. RNA splicing regulators have emerged as a new class of oncoproteins and tumor suppressors, and contribute to disease progression by modulating RNA isoforms involved in the hallmark cancer pathways. Thus, dysregulation of alternative RNA splicing is fundamental to cancer and provides a potentially rich source of novel therapeutic targets. Here, we review the alterations in splicing regulatory factors detected in human tumors, as well as the resulting alternatively spliced isoforms that impact cancer hallmarks, and discuss how they contribute to disease pathogenesis. RNA splicing is a highly regulated process and, as such, the regulators are themselves tightly regulated. Differential transcriptional and posttranscriptional regulation of splicing factors modulates their levels and activities in tumor cells. Furthermore, the composition of the tumor microenvironment can also influence which isoforms are expressed in a given cell type and impact drug responses. Finally, we summarize current efforts in targeting alternative splicing, including global splicing inhibition using small molecules blocking the spliceosome or splicing-factor-modifying enzymes, as well as splice-switching RNA-based therapeutics to modulate cancer-specific splicing isoforms. This article is categorized under: RNA in Disease and Development > RNA in Disease RNA Processing > Splicing Regulation/Alternative Splicing.
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Villamizar O, Chambers CB, Riberdy JM, Persons DA, Wilber A. Long noncoding RNA Saf and splicing factor 45 increase soluble Fas and resistance to apoptosis. Oncotarget 2017; 7:13810-26. [PMID: 26885613 PMCID: PMC4924680 DOI: 10.18632/oncotarget.7329] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 01/29/2016] [Indexed: 12/21/2022] Open
Abstract
In multicellular organisms, cell growth and differentiation is controlled in part by programmed cell death or apoptosis. One major apoptotic pathway is triggered by Fas receptor (Fas)-Fas ligand (FasL) interaction. Neoplastic cells are frequently resistant to Fas-mediated apoptosis, evade Fas signals through down regulation of Fas and produce soluble Fas proteins that bind FasL thereby blocking apoptosis. Soluble Fas (sFas) is an alternative splice product of Fas pre-mRNA, commonly created by exclusion of transmembrane spanning sequences encoded within exon 6 (FasΔEx6). Long non-coding RNAs (lncRNAs) interact with other RNAs, DNA, and proteins to regulate gene expression. One lncRNA, Fas-antisense or Saf, was shown to participate in alternative splicing of Fas pre-mRNA through unknown mechanisms. We show that Saf is localized in the nucleus where it interacts with Fas receptor pre-mRNA and human splicing factor 45 (SPF45) to facilitate alternative splicing and exclusion of exon 6. The product is a soluble Fas protein that protects cells against FasL-induced apoptosis. Collectively, these studies reveal a novel mechanism to modulate this critical cell death program by an lncRNA and its protein partner.
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Affiliation(s)
- Olga Villamizar
- Department of Medical Microbiology, Immunology and Cell Biology, Southern Illinois University School of Medicine, Springfield, Illinois, USA.,Department of Microbiology, Pontificia Universidad Javeriana, Bogotá, Colombia
| | - Christopher B Chambers
- Department of Medical Microbiology, Immunology and Cell Biology, Southern Illinois University School of Medicine, Springfield, Illinois, USA
| | - Janice M Riberdy
- Department of Hematology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Derek A Persons
- Department of Hematology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Andrew Wilber
- Department of Medical Microbiology, Immunology and Cell Biology, Southern Illinois University School of Medicine, Springfield, Illinois, USA
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Abstract
The advent of next-generation sequencing technologies has unveiled a new window into the heterogeneity of acute myeloid leukemia (AML). In particular, recurrent mutations in spliceosome machinery and genome-wide aberrant splicing events have been recognized as a prominent component of this disease. This review will focus on how these factors influence drug resistance through altered splicing of tumor suppressor and oncogenes and dysregulation of the apoptotic signaling network. A better understanding of these factors in disease progression is necessary to design appropriate therapeutic strategies recognizing specific alternatively spliced or mutated oncogenic targets.
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Affiliation(s)
- Rosalia de Necochea-Campion
- Biospecimen Laboratory, Loma Linda University Cancer Center, Loma Linda University School of Medicine, Loma Linda, CA, 92354, USA
| | - Geoffrey P Shouse
- Division of Hematology/Oncology, Loma Linda University School of Medicine, 11175 Campus Street, Chan Shun Pavilion 11015, Loma Linda, CA, 92354, USA
| | - Qi Zhou
- Biospecimen Laboratory, Loma Linda University Cancer Center, Loma Linda University School of Medicine, Loma Linda, CA, 92354, USA
| | - Saied Mirshahidi
- Biospecimen Laboratory, Loma Linda University Cancer Center, Loma Linda University School of Medicine, Loma Linda, CA, 92354, USA
| | - Chien-Shing Chen
- Biospecimen Laboratory, Loma Linda University Cancer Center, Loma Linda University School of Medicine, Loma Linda, CA, 92354, USA. .,Division of Hematology/Oncology, Loma Linda University School of Medicine, 11175 Campus Street, Chan Shun Pavilion 11015, Loma Linda, CA, 92354, USA.
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Abstract
INTRODUCTION The Fas/FasL system plays a significant role in tumorigenesis. Research has shown that its impairment in cancer cells may lead to apoptosis resistance and contribute to tumor progression. Thus, the development of effective therapies targeting the Fas/FasL system may play an important role in the fight against cancer. AREAS COVERED In this review the recent literature on targeting the Fas/FasL system for therapeutic exploitation at different levels is reviewed. Promising pre-clinical approaches and various exceptions are highlighted. The potential of combined therapies is also explored, whereby tumor sensitivity to Fas-mediated apoptosis is restored, before an effective targeted therapy is employed. EXPERT OPINION The success of the Fas/FasL system targeting for therapeutics will require a better understanding of the alterations conferring resistance, in order to use the most appropriate sensitizing chemotherapeutic or radiotherapeutic agents in combination with effective targeted therapies.
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Affiliation(s)
- María Villa-Morales
- Department of Biology, Universidad Autónoma de Madrid, CIBER de Enfermedades Raras, Madrid, Spain
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Spasovski V, Tosic N, Kostic T, Zukic B, Stojiljkovic M, Colovic M, Pavlovic S. The role of FasR/FasL system in pathogenesis of myeloprolyferative neoplasms. ARCH BIOL SCI 2010; 62:223-230. [DOI: 10.2298/abs1002223s] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Myeloproliferative neoplasms (MPN) are hematological malignancies characterized by uncontrolled cell proliferation and impaired apoptosis. The FasR/FasL system is involved in the control of apoptosis in different cell types. Here we have investigated the role of FasR/FasL in the pathogenesis of MPNs. We compared FasR/FasL expression between MPN patients (24) and healthy individuals using the real-time PCR assay. We found an increase of FasR expression in MPN patients. No difference was detected in FasL expression. Mutation V617F in the JAK2 gene, a hallmark of MPN, was detected in 13/24 patients. We found that neither FasR nor FasL expression were related to the presence of JAK2 V617F mutation.
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Yamanegi K, Yamane J, Hata M, Ohyama H, Yamada N, Kato-Kogoe N, Futani H, Nakasho K, Okamura H, Terada N. Sodium valproate, a histone deacetylase inhibitor, decreases the secretion of soluble Fas by human osteosarcoma cells and increases their sensitivity to Fas-mediated cell death. J Cancer Res Clin Oncol 2009; 135:879-89. [PMID: 19066961 DOI: 10.1007/s00432-008-0522-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2008] [Accepted: 11/19/2008] [Indexed: 11/26/2022]
Abstract
PURPOSE Effects of valproic acid (VPA), a histone deacetylase inhibitor, on the susceptibility to cell death induced by agonistic anti-Fas antibody were examined using four human osteosarcoma cell lines. METHOD Cell growth, secretion of soluble Fas, expression of cell-surface Fas, and sensitivity to Fas-mediated cell death were examined using cell proliferation assay, flow cytometry, enzyme-linked immunosorbent assay, and agonistic anti-Fas antibody, respectively. RESULTS VPA suppressed the growth of all the four osteosarcoma cell lines and the secretion of soluble Fas from these cells. VPA showed no or slight suppressive effect on the expression of cell-surface Fas in the four osteosarcoma cell lines, but increased the sensitivity of three of four osteosarcoma cell lines to Fas-mediated cell death. CONCLUSION VPA enhances the susceptibility of human osteosarcoma cells to Fas-ligand-induced cell death by decreasing the secretion of soluble Fas and increasing the sensitivity to Fas-mediated cell death.
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Roesler J, Izquierdo JM, Ryser M, Rösen-Wolff A, Gahr M, Valcarcel J, Lenardo MJ, Zheng L. Haploinsufficiency, rather than the effect of an excessive production of soluble CD95 (CD95{Delta}TM), is the basis for ALPS Ia in a family with duplicated 3' splice site AG in CD95 intron 5 on one allele. Blood 2005; 106:1652-9. [PMID: 15870181 DOI: 10.1182/blood-2004-08-3104] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Autoimmune lymphoproliferative syndrome type Ia (ALPS Ia) is caused by mutations in the CD95/APO1/FAS (TN-FRSF6) gene, which lead to a defective CD95 ligand (CD95L)-induced apoptosis. Soluble CD95 (sCD95) has been suggested to play an important role in the pathogenesis of diverse autoimmune and malignant diseases by antagonizing CD95L. Here we evaluate a family with 4 of its 5 members harboring an ex-6-3C-->G mutation that affects the splice cis regulatory region (cctacag/ex-6-->cctagag/ex-6) of the CD95 gene. The mutation causes skipping of exon-6, which encodes the transmembrane region of CD95, and thereby leads to an excessive production of sCD95 in all 4 affected individuals. The mutation is associated with a low penetrance of disease phenotype and caused mild and transient ALPS in one male patient whereas all other family members are completely healthy. In all family members with the mutation we found that the cell surface expression of CD95 was low and the activated T cells were resistant to CD95-induced apoptosis. Unexpectedly, excessive production or addition of sCD95 had no effect on the CD95-induced apoptosis in diverse cells. In contrast, increasing the surface expression of CD95 was able to correct the defect in apoptosis. Thus we conclude that the ALPS in the one male patient was caused by haploinsufficiency of membrane CD95 expression. Our data challenge the hypothesis that sCD95 causes autoimmunity.
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Affiliation(s)
- Joachim Roesler
- Department of Pediatrics, University Clinic Carl Gustav Carus, Fetscherstr 74, 01307 Dresden, Germany.
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Inaba H, Glibetic M, Buck S, Ravindranath Y, Kaplan J. Interferon-gamma sensitizes osteosarcoma cells to Fas-induced apoptosis by up-regulating Fas receptors and caspase-8. Pediatr Blood Cancer 2004; 43:729-36. [PMID: 15390286 DOI: 10.1002/pbc.20151] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Osteosarcoma is the third most frequent neoplasm in adolescents. Although chemotherapy, frequently used in pre- and post-operative settings, has resulted in significant improvement in disease-free survival, some patients show little sensitivity to chemotherapy and alternative therapeutic strategies are needed. Because the Fas ligand/Fas receptor (CD95, APO-1) apoptosis pathway is a potential therapeutic target in osteosarcomas, we examined the effect of IFN-gamma on Fas-induced apoptosis in four osteosarcoma cell lines. PROCEDURE AND RESULTS As measured by flow cytometry, all cell lines expressed cell surface IFN-gamma receptors, and when cultured for 2 days in the presence of IFN-gamma, all cell lines exhibited a significant increase in expression of Fas receptors. By flow cytometric detection of intracellular fragmented DNA as a marker of apoptosis, all cell lines cultured with either IFN-gamma or anti-Fas antibody (clone CH-11) alone showed only moderate apoptosis, whereas significantly high levels of apoptosis occurred in cells cultured with both IFN-gamma and CH-11. Western blotting analysis also revealed that IFN-gamma caused up-regulation of caspase-8 in all cell lines, but no change in Fas-associated death domain protein (FADD/MORT1) or caspase-3. Both caspase-8 and caspase-3 were activated when apoptosis was induced with both IFN-gamma and CH-11. Addition to cultures of z-IETD-fmk, an inhibitor of caspase-8, significantly blocked this apoptosis. CONCLUSIONS IFN-gamma sensitizes osteosarcoma cells to Fas-induced apoptosis through up-regulation of Fas receptor and caspase-8. Combined immunotherapy with IFN-gamma and either anti-Fas monoclonal antibody or cytotoxic T cells that bear Fas ligand might be a useful adjunctive therapy for patients with osteosarcoma.
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Affiliation(s)
- Hiroto Inaba
- Division of Pediatric Hematology/Oncology, Children's Hospital of Michigan, Detroit, Michigan, USA.
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Abstract
Human group C adenoviruses cause an acute infection in respiratory epithelia and establish a long-term or persistent infection, possibly in lymphocytes. The mechanism by which this persistence is maintained is unknown; however, it would require that persistently infected lymphocytes not be deleted. The adenovirus genome encodes proteins that prevent the immune system from eliminating the virus-infected cell, including the E3 receptor internalization and degradation (RID) complex. The RID complex prevents death of infected cells by blocking apoptosis initiated through death domain-containing receptors of the tumor necrosis factor receptor (TNFR) superfamily, including TNFR1 (L. R. Gooding, T. S. Ranheim, A. E. Tollefson, L. Aquino, P. Duerksen-Hughes, T. M. Horton, and W. S. Wold, J. Virol. 65:4114-4123, 1991), TNF-related apoptosis-inducing ligand receptors (TRAIL-R1 and -R2) (C. A. Benedict, P. S. Norris, T. I. Prigozy, J. L. Bodmer, J. A. Mahr, C. T. Garnett, F. Martinon, J. Tschopp, L. R. Gooding, and C. F. Ware, J. Biol. Chem. 276:3270-3278, 2001; A. E. Tollefson, K. Toth, K. Doronin, M. Kuppuswamy, O. A. Doronina, D. L. Lichtenstein, T. W. Hermiston, C. A. Smith, and W. S. Wold, J. Virol. 75:8875-8887, 2001), and Fas (J. Shisler, C. Yang, B. Walter, C. F. Ware, and L. R. Gooding, J. Virol. 71:8299-8306, 1997). Here, we test the ability of RID to protect human lymphocytes from apoptosis induced by ligation of Fas, a mechanism important for regulating lymphocyte populations. Using a retrovirus expressing RID to infect six human lymphocyte cell lines, we found that RID functions in the absence of other viral proteins to downregulate surface Fas on some, but not all, cell lines. Total cellular levels of Fas decrease as measured by Western blotting, and this loss of Fas correlates with protection from apoptosis induced by ligation of Fas in every cell line tested. Although in some cases, RID causes loss of only a fraction of surface Fas, the presence of RID completely blocks the immediate events downstream of Fas ligation (i.e., Fas-FADD association and caspase-8 cleavage) in susceptible cell lines. Nonetheless, the ability of RID to block Fas signaling is independent of the Fas signaling pathway used (type I or type II). Interestingly, among the four T-cell lines tested, RID caused loss of Fas in the two T-cell lines bearing a relatively immature phenotype, while having no activity in T cells with mature phenotypes. Collectively, these data suggest that RID functions to prevent apoptosis of some human lymphocytes by internalizing surface Fas receptors. It is possible that the expression of RID facilitates long-term infection by preventing Fas-mediated deletion of persistently infected lymphocytes.
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Affiliation(s)
- Adrienne L McNees
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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Hock BD, Patton WN, Budhia S, Mannari D, Roberts P, McKenzie JL. Human plasma contains a soluble form of CD86 which is present at elevated levels in some leukaemia patients. Leukemia 2002; 16:865-73. [PMID: 11986949 DOI: 10.1038/sj.leu.2402466] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2001] [Accepted: 01/17/2002] [Indexed: 11/09/2022]
Abstract
Cell surface expression of CD86 (mCD86) provides an important co-stimulatory signal which profoundly influences immune responses. In this report, we investigated the potential presence of a circulating soluble form of CD86 (sCD86) in normal individuals and patients with acute myeloid leukaemia (AML) or B cell chronic lymphocytic leukaemia (B-CLL). Circulating sCD86 was detected in the plasma of all normal individuals (1.04 +/- 0.33 ng/ml, n = 51) and patients analysed. Plasma collected from AML patients in remission (n = 6) contained only low levels of sCD86 but significantly elevated levels (> or =2.65 ng/ml, P < 0.0001) were detected in 10/24 AML patients analysed at the time of presentation or relapse. Significantly elevated levels of sCD86 were also detected in 2/17 B-CLL patients. There was no correlation between sCD86 levels and other clinical parameters. RT-PCR analysis demonstrated that normal monocytes and dendritic cells, as well as isolated AML (n = 2) and B-CLL (n = 4) cells, expressed an alternatively spliced transcript of CD86 which encoded a soluble form absent in normal T, B and NK cells. The finding that a proportion of leukaemia patients contain elevated levels of sCD86 and that at least some leukaemic cells express sCD86 transcript suggests a potential role for sCD86 in modulating mCD86 signalling during the malignant process.
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MESH Headings
- Acute Disease
- Adolescent
- Adult
- Aged
- Aged, 80 and over
- Alternative Splicing
- Antigens, CD/blood
- Antigens, CD/genetics
- B7-2 Antigen
- Case-Control Studies
- Dendritic Cells/metabolism
- Disease Progression
- Enzyme-Linked Immunosorbent Assay/standards
- Female
- Humans
- Leukemia/blood
- Leukemia/metabolism
- Leukemia/pathology
- Leukemia, Lymphocytic, Chronic, B-Cell/blood
- Leukemia, Lymphocytic, Chronic, B-Cell/metabolism
- Leukemia, Lymphocytic, Chronic, B-Cell/pathology
- Leukemia, Myeloid/blood
- Leukemia, Myeloid/metabolism
- Leukemia, Myeloid/pathology
- Male
- Membrane Glycoproteins/blood
- Membrane Glycoproteins/genetics
- Middle Aged
- Monocytes/metabolism
- RNA, Messenger/analysis
- Solubility
- Up-Regulation
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Affiliation(s)
- B D Hock
- Haematology Research Group, Christchurch Hospital, PO Box 4345, Christchurch, New Zealand
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Abstract
The CD95 receptor, also known as Fas/Apo-1, is a member of the Tumor Necrosis Factor receptor (TNF-R) family of death receptors. Apoptosis mediated by CD95 plays a central role in maintaining homeostasis of the immune system. Dysregulation of the CD95 apoptotic pathway has been proposed as a mechanism of oncogenesis by providing a survival advantage to potentially malignant cells. This extended lifespan could allow the accumulation of further mutations leading to malignant transformation. Several mechanisms of resistance to CD95 mediated apoptosis have been identified, including reduced surface expression of the receptor, overexpression of anti-apoptotic molecules, and loss of function mutations. This review will focus on the potential role of the CD95-CD95 ligand system in the pathogenesis of hematological malignancies, with particular emphasis on recent work from our laboratory examining the expression of CD95 in B cell lymphomas. We demonstrate that CD95 mutations occur at low frequency in NHL tumors, however, surface expression of the CD95 protein varies with the subtype of lymphoma. Loss of surface CD95 is more likely to occur in lymphomas of aggressive histology, and is unrelated to the detection of CD95 mutations.
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Affiliation(s)
- T H Landowski
- Dept. of Interdisciplinary Oncology, H. Lee Moffitt Cancer Center and Research Institute, University of South Florida, Tampa 33612, USA
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Abstract
A cDNA named calmin of approximately 3.2 kb was isolated by RNA differential display applied to developing mouse skin. Calmin cDNA encodes 1021 amino acids with two calponin homology (CH) domains in tandem on the N-terminal side and a transmembrane domain on the C-terminal side. The region covering the CH domains showed a high level of homology with beta-spectrin, alpha-actinin, and dystrophin. Among the proteins with the tandem CH domains, calmin is unique in having a transmembrane domain. Three alternative splicing sites were identified at the 3'-side of calmin, giving rise to polymorphic protein products with or without the transmembrane domain. The calmin transcript was detected in adult testis, liver, kidney, and large intestine; the expression in testis was far stronger than that in the other tissues. In situ hybridization and immunostaining revealed that calmin was expressed in maturing spermatogenic cells at later stages. Human calmin cDNA was also isolated, and its exon/intron organization was determined.
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Affiliation(s)
- Z Ishisaki
- Department of Biochemistry, Faculty of Medicine, Toyama Medical and Pharmaceutical University, Sugitani, Toyama-shi 930-0194, Japan
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