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Postel MD, Darabi S, Howe JR, Liang WS, Craig DW, Demeure MJ. Multiomic sequencing of paired primary and metastatic small bowel carcinoids. F1000Res 2023; 12:417. [PMID: 37954063 PMCID: PMC10632590 DOI: 10.12688/f1000research.130251.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/15/2023] [Indexed: 11/14/2023] Open
Abstract
Background: Small bowel carcinoids are insidious tumors that are often metastatic when diagnosed. Limited mutation landscape studies of carcinoids indicate that these tumors have a relatively low mutational burden. The development of targeted therapies will depend upon the identification of mutations that drive the pathogenesis and metastasis of carcinoid tumors. Methods: Whole exome and RNA sequencing of 5 matched sets of normal tissue, primary small intestine carcinoid tumors, and liver metastases were investigated. Germline and somatic variants included: single nucleotide variants (SNVs), insertions/deletions (indels), structural variants, and copy number alterations (CNAs). The functional impact of mutations was predicted using Ensembl Variant Effect Predictor. Results: Large-scale CNAs were observed including the loss of chromosome 18 in all 5 metastases and 3/5 primary tumors. Certain somatic SNVs were metastasis-specific; including mutations in ATRX, CDKN1B, MXRA5 (leading to the activation of a cryptic splice site and loss of mRNA), SMARCA2, and the loss of UBE4B. Additional mutations in ATRX, and splice site loss of PYGL, leading to intron retention observed in primary and metastatic tumors. Conclusions: We observed novel mutations in primary/metastatic carcinoid tumor pairs, and some have been observed in other types of neuroendocrine tumors. We confirmed a previously observed loss of chromosome 18 and CDKN1B. Transcriptome sequencing added relevant information that would not have been appreciated with DNA sequencing alone. The detection of several splicing mutations on the DNA level and their consequences at the RNA level suggests that RNA splicing aberrations may be an important mechanism underlying carcinoid tumors.
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Affiliation(s)
- Mackenzie D. Postel
- Institute of Translational Genomics, Keck School of Medicine of USC, Los Angeles, CA, USA
| | - Sourat Darabi
- Precision Medicine, Hoag Family Cancer Institute, Newport Beach, CA, 92663, USA
| | - James R. Howe
- Department of Surgery, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | | | - David W. Craig
- Institute of Translational Genomics, Keck School of Medicine of USC, Los Angeles, CA, USA
| | - Michael J. Demeure
- Precision Medicine, Hoag Family Cancer Institute, Newport Beach, CA, 92663, USA
- Translational Genomics Research Institute, Phoenix, AZ, USA
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Shimizu Y, Maruyama K, Suzuki M, Kawachi H, Low SK, Oh-Hara T, Takeuchi K, Fujita N, Nagayama S, Katayama R. Acquired resistance to BRAF inhibitors is mediated by BRAF splicing variants in BRAF V600E mutation-positive colorectal neuroendocrine carcinoma. Cancer Lett 2022; 543:215799. [PMID: 35724767 DOI: 10.1016/j.canlet.2022.215799] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 06/07/2022] [Accepted: 06/15/2022] [Indexed: 11/15/2022]
Abstract
Neuroendocrine carcinomas (NECs), a poorly differentiated subtype of neuroendocrine neoplasms, are aggressive and have a poor prognosis. Colorectal neuroendocrine carcinomas (CRC-NECs) are observed in about 0.6% of all patients with CRC. Interestingly, patients with CRC-NECs show higher frequencies of BRAF mutation than typical CRC. BRAF V600E mutation-positive CRC-NECs were shown to be sensitive to BRAF inhibitors and now are treated by BRAF inhibitors. Similar to the other BRAF V600E mutated cancers, resistances against BRAF inhibitors have been observed, but the resistance mechanisms are still unclear. In this study, we established BRAF V600E mutated CRC-NEC cell line directly from surgical specimens and experimentally obtained BRAF inhibitor dabrafenib resistant cell lines. The resistant cells are revealed to express at least three types of BRAF splicing variants harboring V600E-mutation, and contribute to RAF/MEK/ERK pathway activation. In these cells, MEK and ERK inhibitors but not dabrafenib significantly suppressed cell growth and survival. Thus, in BRAF V600E mutation-positive CRC-NECs, BRAF splicing variants activate the RAF/MEK/ERK pathway and contribute to acquire BRAF inhibitor resistance. Hence, MEK or ERK are potential therapeutic targets to overcome BRAF resistance.
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Affiliation(s)
- Yuki Shimizu
- Division of Experimental Chemotherapy, Cancer Chemotherapy Center, Japanese Foundation for Cancer Research, Tokyo, Japan; Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Tokyo, Japan
| | - Kohei Maruyama
- Division of Experimental Chemotherapy, Cancer Chemotherapy Center, Japanese Foundation for Cancer Research, Tokyo, Japan; Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Tokyo, Japan
| | - Mai Suzuki
- Division of Experimental Chemotherapy, Cancer Chemotherapy Center, Japanese Foundation for Cancer Research, Tokyo, Japan; Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Tokyo, Japan
| | - Hiroshi Kawachi
- Department of Pathology, Cancer Institute Hospital, Japanese Foundation for Cancer Research, Tokyo, Japan; Division of Pathology, Cancer Institute, Japanese Foundation for Cancer Research, Tokyo, Japan
| | - Siew-Kee Low
- Cancer Precision Medicine Center, The Cancer Institute, Japanese Foundation for Cancer Research, Tokyo, Japan
| | - Tomoko Oh-Hara
- Division of Experimental Chemotherapy, Cancer Chemotherapy Center, Japanese Foundation for Cancer Research, Tokyo, Japan
| | - Kengo Takeuchi
- Department of Pathology, Cancer Institute Hospital, Japanese Foundation for Cancer Research, Tokyo, Japan; Division of Pathology, Cancer Institute, Japanese Foundation for Cancer Research, Tokyo, Japan; Pathology Project for Molecular Targets, Cancer Institute Hospital, Japanese Foundation for Cancer Research, Tokyo, Japan
| | - Naoya Fujita
- Cancer Chemotherapy Center, Japanese Foundation for Cancer Research, Tokyo, Japan
| | - Satoshi Nagayama
- Department of Gastroenterological Surgery, Cancer Institute Hospital, Japanese Foundation for Cancer Research, Tokyo, Japan; Department of Surgery, Uji-Tokushukai Medical Center, Kyoto, Japan
| | - Ryohei Katayama
- Division of Experimental Chemotherapy, Cancer Chemotherapy Center, Japanese Foundation for Cancer Research, Tokyo, Japan; Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Tokyo, Japan.
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Pereiro P, Lama R, Figueras A, Novoa B. Characterization of the turbot (Scophthalmus maximus) interleukin-18: Identification of splicing variants, phylogeny, synteny and expression analysis. Dev Comp Immunol 2021; 124:104199. [PMID: 34228995 DOI: 10.1016/j.dci.2021.104199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 07/02/2021] [Accepted: 07/02/2021] [Indexed: 06/13/2023]
Abstract
Interleukin-18 (IL-18) is a pro-inflammatory cytokine that belongs to the interleukin-1 (IL-1) family of cytokines. As occurs with IL-1β, it is synthetized as an inactive precursor peptide that is mainly processed by the cysteine protease caspase-1 in the inflammasome complex. In mammals, and in collaboration with IL-12, it has been described as an important cytokine controlling the Th1-mediated immune responses through the induction of IFN-γ. Although its function in mammals is well stablished, the activity of this cytokine in teleost remains to be elucidated. This could be due, among other things, to the absence of this gene in the fish model species zebrafish, but also to its complex regulation. As it was observed for rainbow trout and human, il18 splicing variants were also found in turbot, which could represent a regulatory mechanism of its bioactivity. In the case of turbot, three splicing variants were observed (SV1-3), and one of them showed an insertion of 10 amino acids in the middle of the potential caspase-1 cleavage position, reflecting that this is probably a form resistant to the processing by the inflammasome. Phylogenetic and three-dimensional analyses of turbot Il18 revealed that it is relatively well-conserved in vertebrates, although only a partial conservation of the gene synteny was observed between fish and mammals. As it was expected, turbot il18 splicing variants were mainly expressed in immune tissues under healthy conditions, and their expression was induced by a bacterial challenge, although certain inhibitions were observed after viral and parasitic infections. In the case of the viral challenge, il18 downregulations did not seem to be due to the effect of type I IFNs.
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Affiliation(s)
- Patricia Pereiro
- Instituto de Investigaciones Marinas (IIM), Consejo Superior de Investigaciones Científicas (CSIC), C/ Eduardo Cabello 6, 36208, Vigo, Spain
| | - Raquel Lama
- Instituto de Investigaciones Marinas (IIM), Consejo Superior de Investigaciones Científicas (CSIC), C/ Eduardo Cabello 6, 36208, Vigo, Spain
| | - Antonio Figueras
- Instituto de Investigaciones Marinas (IIM), Consejo Superior de Investigaciones Científicas (CSIC), C/ Eduardo Cabello 6, 36208, Vigo, Spain
| | - Beatriz Novoa
- Instituto de Investigaciones Marinas (IIM), Consejo Superior de Investigaciones Científicas (CSIC), C/ Eduardo Cabello 6, 36208, Vigo, Spain.
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Fang Z, Wu B, Ji Y. The Amino Acid Transporter OsAAP4 Contributes to Rice Tillering and Grain Yield by Regulating Neutral Amino Acid Allocation through Two Splicing Variants. Rice (N Y) 2021; 14:2. [PMID: 33409665 PMCID: PMC7788160 DOI: 10.1186/s12284-020-00446-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 12/06/2020] [Indexed: 05/27/2023]
Abstract
BACKGROUND Amino acids, which are transported by amino acid transporters, are the major forms of organic nitrogen utilized by higher plants. Among the 19 Amino Acid Permease transporters (AAPs) in rice, only a small number of these genes have been reported to influence rice growth and development. However, whether other OsAAPs are responsible for rice growth and development is unclear. RESULTS In this study, we demonstrate that OsAAP4 promoter sequences are divergent between Indica and Japonica, with higher expression in the former, which produces more tillers and higher grain yield than does Japonica. Overexpression of two different splicing variants of OsAAP4 in Japonica ZH11 significantly increased rice tillering and grain yield as result of enhancing the neutral amino acid concentrations of Val, Pro, Thr and Leu. OsAAP4 RNA interference (RNAi) and mutant lines displayed opposite trends compared with overexpresing (OE) lines. In addition, exogenous Val or Pro at 0.5 mM significantly promoted the bud outgrowth of lines overexpressing an OsAAP4a splicing variant compared with ZH11, and exogenous Val or Pro at 2.0 mM significantly enhanced the bud outgrowth of lines overexpressing splicing variant OsAAP4b compared with ZH11. Of note, the results of a protoplast amino acid-uptake assay showed that Val or Pro at different concentrations was specifically transported and accumulated in these overexpressing lines. Transcriptome analysis further demonstrated that OsAAP4 may affect nitrogen transport and metabolism, and auxin, cytokinin signaling in regulating rice tillering. CONCLUSION Our results suggested that OsAAP4 contributes to rice tiller and grain yield by regulating neutral amino acid allocation through two different splicing variants and that OsAAP4 might have potential applications in rice breeding.
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Affiliation(s)
- Zhongming Fang
- Key Laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), College of Agricultural Sciences, Guizhou University, Guiyang, 550025, China.
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China.
| | - Bowen Wu
- Key Laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), College of Agricultural Sciences, Guizhou University, Guiyang, 550025, China
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China
| | - Yuanyuan Ji
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China
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Johnstone T, Wang J, Ross D, Balanda N, Huang Y, Godfrey R, Groden C, Barton BR, Gahl W, Toro C, Malicdan MCV. Biallelic variants in two complex I genes cause abnormal splicing defects in probands with mild Leigh syndrome. Mol Genet Metab 2020; 131:98-106. [PMID: 33097395 PMCID: PMC7749052 DOI: 10.1016/j.ymgme.2020.09.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 09/29/2020] [Accepted: 09/30/2020] [Indexed: 11/25/2022]
Abstract
Leigh syndrome is a genetically heterogeneous disorder resulting from deficient oxidative energy biogenesis. The syndrome is characterized by subacute episodic decompensations, transiently elevated lactate, and necrotizing brain lesions most often in the striatum and brainstem. Acute decompensation is often triggered by viral infections. Sequalae from repeated episodes leads to progressive neurological deterioration and death. The severity of Leigh syndrome varies widely, from a rapid demise in childhood to rare adult presentations. Although the causes of Leigh syndrome include genes affecting a variety of different pathways, more than 75 of them are nuclear or mitochondrial encoded genes involved in the assembly and catalytic activity of mitochondrial respiratory complex I. Here we report the detailed clinical and molecular phenotype of two adults with mild presentations of NDUFS3 and NDUFAF6-related Leigh Syndrome. Mitochondrial assays revealed slightly reduced complex I activity in one proband and normal complex I activity in the other. The proband with NDUFS3-related Leigh syndrome was mildly affected and lived into adulthood with novel biallelic variants causing aberrant mRNA splicing (NM_004551.2:c.419G > A; p.Arg140Gln; NM_004551.2:c.381 + 6 T > C). The proband with NDUFAF6-related Leigh syndrome had biallelic variants that cause defects in mRNA splicing (NM_152416.3:c.371 T > C; p.Ile124Thr; NM_152416.3:c.420 + 2_420 + 3insTA). The mild phenotypes of these two individuals may be attributed to some residual production of normal NDUFS3 and NDUFAF6 proteins by NDUFS3 and NDUFAF6 mRNA isoforms alongside mutant transcripts. Taken together, these cases reported herein suggest that splice-regulatory variants to complex I proteins could result in milder phenotypes.
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Affiliation(s)
- Thomas Johnstone
- NIH Undiagnosed Diseases Program, National Institutes of Health, Bethesda, MD, USA; United States Naval Academy, Annapolis, MD, USA
| | - Jennifer Wang
- NIH Undiagnosed Diseases Program, National Institutes of Health, Bethesda, MD, USA
| | - Daron Ross
- NIH Undiagnosed Diseases Program, National Institutes of Health, Bethesda, MD, USA
| | - Nicholas Balanda
- NIH Undiagnosed Diseases Program, National Institutes of Health, Bethesda, MD, USA
| | - Yan Huang
- NIH Undiagnosed Diseases Program, National Institutes of Health, Bethesda, MD, USA
| | - Rena Godfrey
- NIH Undiagnosed Diseases Program, National Institutes of Health, Bethesda, MD, USA; National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Catherine Groden
- NIH Undiagnosed Diseases Program, National Institutes of Health, Bethesda, MD, USA; National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Brandon R Barton
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, USA
| | - William Gahl
- NIH Undiagnosed Diseases Program, National Institutes of Health, Bethesda, MD, USA; National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Camilo Toro
- NIH Undiagnosed Diseases Program, National Institutes of Health, Bethesda, MD, USA; National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - May Christine V Malicdan
- NIH Undiagnosed Diseases Program, National Institutes of Health, Bethesda, MD, USA; National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA.
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Kajiura H, Nakamura Y, Nishimura M, Ohashi T, Misaki R, Fujiyama K. Characterization of Bombyx mori N-acetylglucosaminyltransferase II splicing variants. Biochem Biophys Res Commun 2020; 529:404-10. [PMID: 32703443 DOI: 10.1016/j.bbrc.2020.05.065] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Accepted: 05/07/2020] [Indexed: 11/21/2022]
Abstract
N-Acetylglucosaminyltransferase II (GNTII), which catalyzes the transfer of N-acetylglucosamine to N-glycans, plays an essential role in the biosynthesis of branched and complex-type N-glycans. Some characteristics of the GNTIIs from various species have been identified, but not all features have been revealed because some insects have GNTII redundancies due to the possession of splicing variants. In this study, we focused on four splicing variants of silkworm Bombyx mori GNTII (BmGNTII) that differ only in the absence or presence of Exon 2, Exon 9 or both, and we characterized the spatiotemporal transcript levels and enzymatic properties of each. Two of the splicing variants, BmGNTII-B and BmGNTII-D, lack Exon 9, and were expressed more highly in silk glands than any other organs. With respect to the enzymatic properties, optimal temperature and pH were similar among the recombinant BmGNTIIs, but the specific activities and temperature stabilities differed according to the presence or absence of Exon 9 in the splicing variants. These results demonstrate that the B. mori genome encodes splicing variants of GNTII with different enzymatic properties.
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7
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Romero A, Vega M, Santibáñez N, Spies J, Pérez T, Enríquez R, Kausel G, Oliver C, Oyarzún R, Tort L, Vargas-Chacoff L. Salmo salar glucocorticoid receptors analyses of alternative splicing variants under stress conditions. Gen Comp Endocrinol 2020; 293:113466. [PMID: 32194046 DOI: 10.1016/j.ygcen.2020.113466] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 03/12/2020] [Accepted: 03/14/2020] [Indexed: 11/21/2022]
Abstract
Cortisol is the main corticosteroid in teleosts, exerting multiple functions by activating glucocorticoid receptors (GR). Most teleost species have two GR genes, gr-1 and gr-2. Some teleost also presents two splice variants for gr-1; gr-1a and gr-1b. In this study, we report for first time the presence of 2 homeologous genes for gr-1 and gr-2, located on chromosomes 4q-13q (gr-1) and 5p-9q (gr-2) of the Salmo salar genome. Furthermore, our results describe gr-1 splice variants derived from chromosome 4 and 13, sharing typical teleost GR elements such as the 9 amino acid insertion in the DNA binding domain (DBD) and variations in the length of the ligand binding domain (LBD). Three splice variants were predicted for the gr-2 homeologous gene in chromosome 5, with differences of a 5 amino acid insertion in the DBD. We also identified an uncommon truncated gr-2 gene in chromosome 9 in salmon, which lacked the DBD and LBD domains. Finally, by designing specific primers for each predicted splice variant, we validated and evaluated the expression of their transcripts in S. salar subjected to stress caused by stocking density. Differences were observed in the expression of all identified mRNAs, revealing that gr-1 and gr-2 splice variants were upregulated in head kidney and gills of post-stressed fish. In conclusion, our findings suggest that from specific salmonid genomic duplication (125 MYA), two gene copies of each GR receptor were generated in S. salar. The identified splice variants could contribute to the variability of GR receptor complex modulation expression during stressful events, leading to variations in physiological responses in fish.
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Affiliation(s)
- Alex Romero
- Instituto de Patología Animal, Facultad de Ciencias Veterinarias, Universidad Austral De Chile, Chile; Interdisciplinary Center for Aquaculture Research (INCAR), Centro FONDAP, Chile.
| | - Matías Vega
- Instituto de Patología Animal, Facultad de Ciencias Veterinarias, Universidad Austral De Chile, Chile; Interdisciplinary Center for Aquaculture Research (INCAR), Centro FONDAP, Chile
| | - Natacha Santibáñez
- Instituto de Patología Animal, Facultad de Ciencias Veterinarias, Universidad Austral De Chile, Chile; Interdisciplinary Center for Aquaculture Research (INCAR), Centro FONDAP, Chile
| | - Johana Spies
- Instituto de Patología Animal, Facultad de Ciencias Veterinarias, Universidad Austral De Chile, Chile; Instituto de Ciencias Marinas y Limnológicas, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
| | - Tatiana Pérez
- Instituto de Patología Animal, Facultad de Ciencias Veterinarias, Universidad Austral De Chile, Chile; Interdisciplinary Center for Aquaculture Research (INCAR), Centro FONDAP, Chile
| | - Ricardo Enríquez
- Instituto de Patología Animal, Facultad de Ciencias Veterinarias, Universidad Austral De Chile, Chile.
| | - Gudrun Kausel
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral De Chile, Chile.
| | - Cristian Oliver
- Instituto de Patología Animal, Facultad de Ciencias Veterinarias, Universidad Austral De Chile, Chile; Interdisciplinary Center for Aquaculture Research (INCAR), Centro FONDAP, Chile
| | - Ricardo Oyarzún
- Instituto de Ciencias Marinas y Limnológicas, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile; Centro Fondap de Investigación de Altas Latitudes (IDEAL), Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
| | - Lluis Tort
- Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, 08193 Barcelona, Spain.
| | - Luis Vargas-Chacoff
- Instituto de Ciencias Marinas y Limnológicas, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile; Centro Fondap de Investigación de Altas Latitudes (IDEAL), Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile.
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Poderoso T, Martínez de la Riva P, Uenishi H, Alvarez B, Toki D, Nieto-Pelegrín E, Alonso F, Domínguez J, Ezquerra A, Revilla C. Analysis of the expression of porcine CD200R1 and CD200R1L by using newly developed monoclonal antibodies. Dev Comp Immunol 2019; 100:103417. [PMID: 31233758 DOI: 10.1016/j.dci.2019.103417] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 06/20/2019] [Accepted: 06/20/2019] [Indexed: 06/09/2023]
Abstract
CD200R1 and CD200R1-like are paired receptors which modulate activation of immune cells. Here, we describe the characterisation of their porcine homologues. Analysis of database porcine sequences shows an exceptionally high homology between the extracellular Ig-like domains of these receptors, being the rest more dissimilar. We have obtained two mAbs, PCT1 and PCT3, against a CD200R1-Fc recombinant protein, that bind on CHO cells expressing GFP-tagged CD200R1. The specificity of these mAbs was analysed on CD200R1 L, and also on a CD200R1 splicing variant that lacks the V-type Ig domain. PCT1 bound to both CD200R1 and CD200R1L, but not to the splicing variant, what suggests that recognises an epitope in the V-type Ig domain. PCT3 reacted with both CD200R1 variants, but not CD200R1L, probably binding to an epitope in the N-terminal sequence of CD200R1. Analysis of porcine cells with these mAbs showed expression of CD200R1/CD200R1L on B cells, monocytes and alveolar macrophages.
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Affiliation(s)
- T Poderoso
- Dpto. Biotecnología, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 28040, Madrid, Spain
| | - P Martínez de la Riva
- Dpto. Biotecnología, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 28040, Madrid, Spain
| | - H Uenishi
- National Agriculture and Food Research Organization (NARO), 1-2 Owashi, Tsukuba, Ibaraki, 305-8634, Japan
| | - B Alvarez
- Dpto. Biotecnología, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 28040, Madrid, Spain
| | - D Toki
- Institute of Japan Association for Techno-innovation in Agriculture, Forestry and Fisheries, 446-1 Ippaizuka, Kamiyokoba, Tsukuba, Ibaraki, 305-0854, Japan
| | - E Nieto-Pelegrín
- Dpto. Biotecnología, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 28040, Madrid, Spain
| | - F Alonso
- Dpto. Biotecnología, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 28040, Madrid, Spain
| | - J Domínguez
- Dpto. Biotecnología, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 28040, Madrid, Spain
| | - A Ezquerra
- Dpto. Biotecnología, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 28040, Madrid, Spain
| | - C Revilla
- Dpto. Biotecnología, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 28040, Madrid, Spain.
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Rabacchi C, Simone ML, Pisciotta L, Di Leo E, Bocchi D, Pietrangelo A, D'Addato S, Bertolini S, Calandra S, Tarugi P. In vitro functional characterization of splicing variants of the APOB gene found in familial hypobetalipoproteinemia. J Clin Lipidol 2019; 13:960-9. [PMID: 31629702 DOI: 10.1016/j.jacl.2019.09.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Revised: 08/22/2019] [Accepted: 09/06/2019] [Indexed: 11/23/2022]
Abstract
BACKGROUND Familial hypobetalipoproteinemia type 1 (FHBL-1) is a codominant disorder characterized by greatly reduced plasma levels of total cholesterol, low-density lipoprotein cholesterol, and apolipoprotein B. Rare exonic pathogenic variants of APOB gene (nonsense variants, minute deletions/insertions and nonsynonymous variants) have been frequently reported in subjects with FHBL-1. Also, rare intronic variants of APOB located at intron/exon junctions and assumed to affect splicing have been reported. However, the pathogenicity of most of these intronic variants remains to be established. OBJECTIVE The objective of this study was the in vitro functional characterization of six splicing variants of APOB gene identified in seven putative FHBL-1 heterozygotes. METHODS ApoB minigenes harboring each variant were expressed in COS-1 cells and their transcripts were sequenced. RESULTS Four novel variants (c.237+1G>A, c.818+5G>A, c.3000-1G>T, and c.3842+1G>A), predicted in silico to obliterate splice site activity, were found to generate abnormal transcripts. The abnormal transcripts were generated by the activation of cryptic splice sites or exon skipping. All these transcripts harbored a premature termination codon and were predicted to encode truncated apoBs devoid of function. The predicted translation products were: i) p.(Lys41Serfs*2) and p.(Val80Ilefs*10) for c.237+1G>A; ii) p.(Asn274*) for c.818+5G>A; iii) p.(Leu1001Alafs*10) for c.3000-1G>T, and iv) p.(Ser1281Argfs*2) for c.3842+1G>A. Two previously annotated rare variants (c.905-15C>G and c.1618-4G>A) with uncertain effect in silico were found to generate only wild-type transcripts. CONCLUSIONS These in vitro minigene expression studies support the assignment of pathogenicity to four novel splice site variants of APOB gene found in FHBL-1.
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Matsumoto A, Matsuura N, Hieda M. Detection of SUN1 Splicing Variants at the mRNA and Protein Levels in Cancer. Methods Mol Biol 2018; 1840:307-19. [PMID: 30141053 DOI: 10.1007/978-1-4939-8691-0_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
The linker of nucleoskeleton and cytoskeleton (LINC) complex, containing the proteins SUN and nesprin, is the fundamental structural unit of the nuclear envelope. The neoplastic-based regulation of the LINC complex in cancer tissues has become increasingly recognized in recent years, including the altered expression, somatic mutation, and methylation of genes. However, precisely how mutations and deregulated expression of the LINC complex contribute to the pathogenic mechanisms of tumorigenesis remain to be elucidated, mainly because of several technical difficulties. First, both the SUN and SYNE (encoding nesprin) genes give rise to a vast number of splicing variants. Second, immunoprecipitation experiments of endogenous SUN and nesprin proteins are difficult owing to the lack of suitable reagents as well as the limited solubility of these proteins in mild extraction conditions. Here, we describe three protocols to investigate these aspects: (1) immunohistochemistry to determine the expression levels and localization of the LINC complex in cancer tissue, (2) detection of SUN1 splicing variants at the mRNA level, and (3) detection of SUN1 splicing variants and binding partners at the protein level.
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Sato A, Kim JD, Mizukami H, Nakashima M, Kako K, Ishida J, Itakura A, Takeda S, Fukamizu A. Gestational changes in PRMT1 expression of murine placentas. Placenta 2018; 65:47-54. [PMID: 29908641 DOI: 10.1016/j.placenta.2018.04.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 03/24/2018] [Accepted: 04/06/2018] [Indexed: 10/17/2022]
Abstract
INTRODUCTION In mammals, the placenta is an organ that is required to maintain the development of fetus during pregnancy. Although the proper formation of placenta is in part regulated by the post-translational modifications of proteins, little is known regarding protein arginine methylation during placental development. Here, we characterized developmental expression of protein arginine methyltransferase 1 (PRMT1) in mouse placentas. METHODS Expression levels of PRMT1 mRNA and protein in placentas were investigated using the real-time quantitative PCR and Western blot, respectively. Next, the localization of PRMT1 was determined by immunohistochemistry and immunofluorescence analyses. In addition, the levels of methylarginines of placental proteins were quantified using liquid chromatography-tandem mass spectrometry (LC-MS/MS). RESULTS PRMT1 mRNA and its protein were expressed at highest levels in mid-gestation stages, and their expression showed stepwise decrease in the late gestation. At embryonic (E) day 9, PRMT1 was observed in several different trophoblast cell (TC) subtypes. Furthermore, PRMT1 was mainly expressed in the labyrinth zone of TCs at E13. Finally, total methylarginines of proteins were significantly reduced in late gestation of placentas compared with mid-gestation stages. DISCUSSION In this study, we found developmental changes in the placental expression of PRMT1 and in protein arginine methylation status during pregnancy. These findings provide fundamental information regarding placental PRMT1-mediated arginine methylation during the development.
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Affiliation(s)
- Anna Sato
- Department of Obstetrics and Gynecology, Juntendo University Faculty of Medicine, 2-1-1 Hongo, Bunkyoku, Tokyo 113-8421, Japan
| | - Jun-Dal Kim
- Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan
| | - Hayase Mizukami
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan
| | - Misaki Nakashima
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan
| | - Koichiro Kako
- Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan
| | - Junji Ishida
- Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan
| | - Atsuo Itakura
- Department of Obstetrics and Gynecology, Juntendo University Faculty of Medicine, 2-1-1 Hongo, Bunkyoku, Tokyo 113-8421, Japan
| | - Satoru Takeda
- Department of Obstetrics and Gynecology, Juntendo University Faculty of Medicine, 2-1-1 Hongo, Bunkyoku, Tokyo 113-8421, Japan
| | - Akiyoshi Fukamizu
- Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan.
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Mahdieh N, Mikaeeli S, Badv RS, Shirazi AG, Maleki M, Rabbani B. Pathogenic significance of SCN1A splicing variants causing Dravet syndrome: Improving diagnosis with targeted sequencing for variants by in silico analysis. Clin Neurol Neurosurg 2018; 166:80-90. [PMID: 29408779 DOI: 10.1016/j.clineuro.2018.01.030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 01/21/2018] [Accepted: 01/27/2018] [Indexed: 12/28/2022]
Abstract
OBJECTIVES Genetic heterogeneity of epileptic encephalopathy (IEE) mandates the use of gene-panels for diagnosis. PATIENTS AND METHODS A 36-gene-panel next-generation sequencing was applied for IEE in two Iranian families. A literature search was performed using keywords to identify reported splicing mutations in SCN1A and perform genotype-phenotype correlation. RESULTS An update of splicing mutations revealed 147 variants with 65.75% of them de novo mutations. Most of the familial variants were of parental origin. The structure of the protein was often affected in the linker and transmembrane segments. 92% of intronic variants were pathogenic. A de novo heterozygous mutation was found in the first patient, but not in her sibling and parents. In the second family, a novel de novo heterozygous mutation was found at position c.1210insT leading to a truncated protein. CONCLUSION Gene-panel sequencing is helpful for reducing the time and cost, guiding early treatment, and estimating the recurrence risks. The importance of characterization of intronic variants was noticed; though bioinformatics analysis of novel intronic variants should be of concern for rapid reporting the pathogenic effect of variants.
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Affiliation(s)
- Nejat Mahdieh
- Genetic Research Laboratory, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran.
| | - Sepideh Mikaeeli
- Genetic Research Laboratory, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Reza Shervin Badv
- Children's Hospital Center, Pediatric Center of Excellence, Tehran University of Medical Center, Tehran, Iran
| | - Azadeh Gharehzadeh Shirazi
- Children's Hospital Center, Pediatric Center of Excellence, Tehran University of Medical Center, Tehran, Iran
| | - Majid Maleki
- Genetic Research Laboratory, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Bahareh Rabbani
- Genetic Research Laboratory, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran.
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Abstract
Solid tumors are composed of mutually interacting cancer cells and tumor microenvironment. Many environmental components, such as extracellular matrix (ECM), mesenchymal stem cells, endothelial and immune cells, and various growth factors and cytokines, provide signals, either stimulatory or inhibitory, to cancer cells and determine their fates. Meanwhile, cancer cells can also educate surrounding cells or tissues to undergo changes that are in favorable of tumor progression. CD44, as a transmembrane receptor for hyaluronic acid (HA) and many other ECM components and a coreceptor for growth factors and cytokines, is a critical cell surface molecule that can sense, integrate, and transduce cellular microenvironmental signals to membrane-associated cytoskeletal proteins or to cell nucleus to regulate a variety of gene expressions that govern cell behaviors. Mounting evidence suggests that CD44, particularly CD44v isoforms, are cancer stem cell (CSC) markers and critical regulators of cancer stemness, including self-renewal, tumor initiation, and metastasis. Thus, CD44 is widely used alone or in combination with other cell surface markers to isolate or enrich CSCs through fluorescence-activated cell sorting of dissociated single cells that originate from the patient, xenograft tumor tissues, or tumor cell cultures. Sorted cells are cultured in a specialized culture medium for spheroid formation or inoculated into immunodeficient mice for the analysis of tumorigenic or metastatic potential. In this chapter, detailed experimental methods regarding CD44+ tumor cell isolation, spheroid culture, and characterization will be described.
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Affiliation(s)
- Liang Wang
- Department of Gastroenterology, Hepatology and Nutrition, The University of Texas MD Anderson Cancer Center, Unit 1466, 1515 Holcombe Blvd, Houston, TX, 77030, USA
| | - Xiangsheng Zuo
- Department of Gastrointestinal Medical Oncology, The University of Texas MD Anderson Cancer Center, Unit 956, 1515 Holcombe Blvd, Houston, TX, 77030, USA
| | - Keping Xie
- Department of Gastroenterology, Hepatology and Nutrition, The University of Texas MD Anderson Cancer Center, Unit 1466, 1515 Holcombe Blvd, Houston, TX, 77030, USA
| | - Daoyan Wei
- Department of Gastroenterology, Hepatology and Nutrition, The University of Texas MD Anderson Cancer Center, Unit 1466, 1515 Holcombe Blvd, Houston, TX, 77030, USA.
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Noyes AM, Zhou A, Gao G, Gu L, Day S, Andrew Wasserstrom J, Dudley SC. Abnormal sodium channel mRNA splicing in hypertrophic cardiomyopathy. Int J Cardiol 2017; 249:282-6. [PMID: 28916354 DOI: 10.1016/j.ijcard.2017.08.071] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 08/03/2017] [Accepted: 08/29/2017] [Indexed: 01/21/2023]
Abstract
BACKGROUND Our previous studies showed that in ischemic and nonischemic heart failure (HF), the voltage-gated cardiac Na+ channel α subunit (SCN5A) mRNA is abnormally spliced to produce two truncated transcript variants (E28C and D) that activate the unfolded protein response (UPR). We tested whether SCN5A post-transcriptional regulation was abnormal in hypertrophic cardiomyopathy (HCM). MATERIAL AND METHODS Human heart tissue was obtained from HCM patients. The changes in relative abundances of SCN5A, its variants, splicing factors RBM25 and LUC7A, and PERK, a major effector of the UPR, were analyzed by real time RT-PCR and the expression changes were confirmed by Western Blot. RESULTS We found reduced full-length transcript, increased SCN5A truncation variants and activation of UPR in HCM when compared to control hearts. In these patients, real time RT-PCR revealed that HCM patients had decreased SCN5A mRNA to 27.8±4.07% of control (P<0.01) and an increased abundance of E28C and E28D (3.4±0.3 and 2.8±0.3-fold, respectively, P<0.05). PERK mRNA increased 8.2±3.1 fold (P<0.01) in HCM patients. Western blot confirmed a significant increase of PERK. CONCLUSIONS These data suggested that the full-length SCN5A was reduced in patients with HCM. This reduction was accompanied by abnormal SCN5A pre-mRNA splicing and UPR activation. These changes may contribute to the arrhythmic risk in HCM.
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Yan Y, Zuo X, Wei D. Concise Review: Emerging Role of CD44 in Cancer Stem Cells: A Promising Biomarker and Therapeutic Target. Stem Cells Transl Med 2015; 4:1033-43. [PMID: 26136504 DOI: 10.5966/sctm.2015-0048] [Citation(s) in RCA: 427] [Impact Index Per Article: 47.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 05/26/2015] [Indexed: 12/12/2022] Open
Abstract
UNLABELLED The reception and integration of the plethora of signals a cell receives from its microenvironment determines the cell's fate. CD44 functions as a receptor for hyaluronan and many other extracellular matrix components, as well as a cofactor for growth factors and cytokines, and thus, CD44 is a signaling platform that integrates cellular microenvironmental cues with growth factor and cytokine signals and transduces signals to membrane-associated cytoskeletal proteins or to the nucleus to regulate a variety of gene expression levels related to cell-matrix adhesion, cell migration, proliferation, differentiation, and survival. Accumulating evidence indicates that CD44, especially CD44v isoforms, are cancer stem cell (CSC) markers and critical players in regulating the properties of CSCs, including self-renewal, tumor initiation, metastasis, and chemoradioresistance. Furthermore, there is ample evidence that CD44, especially CD44v isoforms, are valuable prognostic markers in various types of tumors. Therefore, therapies that target CD44 may destroy the CSC population, and this holds great promise for the cure of life-threatening cancers. However, many challenges remain to determining how best to use CD44 as a biomarker and therapeutic target. Here we summarize the current findings concerning the critical role of CD44/CD44v in the regulation of cancer stemness and the research status of CD44/CD44v as biomarkers and therapeutic targets in cancer. We also discuss the current challenges and future directions that may lead to the best use of CD44/CD44v for clinical applications. SIGNIFICANCE Mounting evidence indicates that cancer stem cells (CSCs) are mainly responsible for cancer aggressiveness, drug resistance, and tumor relapse. CD44, especially CD44v isoforms, have been identified as CSC surface markers for isolating and enriching CSCs in different types of cancers. The current findings concerning the critical role of CD44/CD44v in regulation of cancer stemness and the research status of CD44/CD44v as biomarkers and therapeutic targets in cancer are summarized. The current challenges and future directions that may lead to best use of CD44/CD44v for clinical applications are also discussed.
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Affiliation(s)
- Yongmin Yan
- Departments of Gastroenterology, Hepatology & Nutrition and Gastrointestinal Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA; School of Medical Sciences and Laboratory Medicine, Jiangsu University, Zhenjiang, People's Republic of China
| | - Xiangsheng Zuo
- Departments of Gastroenterology, Hepatology & Nutrition and Gastrointestinal Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA; School of Medical Sciences and Laboratory Medicine, Jiangsu University, Zhenjiang, People's Republic of China
| | - Daoyan Wei
- Departments of Gastroenterology, Hepatology & Nutrition and Gastrointestinal Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA; School of Medical Sciences and Laboratory Medicine, Jiangsu University, Zhenjiang, People's Republic of China
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Abstract
Despite castrate levels of androgens, the androgen receptor (AR) remains active and continues to drive prostate cancer progression. Since the approval of docetaxel, four additional agents that show a survival benefit have been registered on the basis of randomized phase 3 trials. These have included enzalutamide and abiraterone, two agents designed specifically to affect the androgen axis, sipuleucel-T, which stimulates the immune system and cabazitaxel, a chemotherapeutic agent. Denosumab was shown to significantly delay skeletal-related events. Clinicians are challenged with a multitude of treatment options and potential sequencing of these agents that, consequently, make clinical decision making more complex. The induction of constitutively-active AR splice variants (AR-Vs) driving clonal proliferation of AR-negative and AR-independent metastases may be one major potential mechanism of resistance to new hormone therapies.
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Affiliation(s)
- Philippe Beuzeboc
- Institut Curie, département d'oncologie médicale, 26, rue d'Ulm, 75005 Paris, France.
| | - Christophe Massard
- Institut Gustave-Roussy, département d'oncologie médicale, 94076 Villejuif, France
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Kazemi Noureini S, Tanavar F. Boldine, a natural aporphine alkaloid, inhibits telomerase at non-toxic concentrations. Chem Biol Interact 2015; 231:27-34. [PMID: 25746354 DOI: 10.1016/j.cbi.2015.02.020] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2014] [Revised: 01/31/2015] [Accepted: 02/23/2015] [Indexed: 11/20/2022]
Abstract
In a preliminary screening study of natural alkaloids, boldine, an aporphine alkaloid, showed an interesting dose and time dependent anti-proliferative effect in several cancer cell lines. Cytotoxicity of boldine in human fibroblasts was considerably lower than the telomerase positive embryonic kidney HEK293 and breast cancer MCF-7 and MDA-MB-231 cells. Whether boldine can inhibit telomerase was investigated here using a modified quantitative real-time telomere repeat amplification protocol (q-TRAP). This test showed that boldine inhibits telomerase in cells treated with sub-cytotoxic concentrations. Telomerase inhibition occurs via down-regulation of hTERT, the catalytic subunit of the enzyme. Boldine changed the splicing variants of hTERT towards shorter non-functional transcripts as well. A direct interaction of boldine with the enzyme may also be involved, though thermal FRET method did not detect any substantial interaction between boldine and synthetic telomere sequences. This study advocates boldine as a valuable candidate for telomerase-targeted cancer care. This study suggests that derivatives of boldine could be potent anti-cancer drugs.
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Cancela ML, Laizé V, Conceição N. Matrix Gla protein and osteocalcin: from gene duplication to neofunctionalization. Arch Biochem Biophys 2014; 561:56-63. [PMID: 25068814 DOI: 10.1016/j.abb.2014.07.020] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 07/04/2014] [Accepted: 07/15/2014] [Indexed: 12/31/2022]
Abstract
Osteocalcin (OC or bone Gla protein, BGP) and matrix Gla protein (MGP) are two members of the growing family of vitamin K-dependent (VKD) proteins. They were the first VKD proteins found not to be involved in coagulation and synthesized outside the liver. Both proteins were isolated from bone although it is now known that only OC is synthesized by bone cells under normal physiological conditions, but since both proteins can bind calcium and hydroxyapatite, they can also accumulate in bone. Both OC and MGP share similar structural features, both in terms of protein domains and gene organization. OC gene is likely to have appeared from MGP through a tandem gene duplication that occurred concomitantly with the appearance of the bony vertebrates. Despite their relatively close relationship and the fact that both can bind calcium and affect mineralization, their functions are not redundant and they also have other unrelated functions. Interestingly, these two proteins appear to have followed quite different evolutionary strategies in order to acquire novel functionalities, with OC following a gene duplication strategy while MGP variability was obtained mostly by the use of multiple promoters and alternative splicing, leading to proteins with additional functional characteristics and alternative gene regulatory pathways.
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Affiliation(s)
- M Leonor Cancela
- Centre of Marine Sciences, University of Algarve, 8005-139 Faro, Portugal; Department of Biomedical Sciences and Medicine, University of Algarve, 8005-139 Faro, Portugal.
| | - Vincent Laizé
- Centre of Marine Sciences, University of Algarve, 8005-139 Faro, Portugal
| | - Natércia Conceição
- Centre of Marine Sciences, University of Algarve, 8005-139 Faro, Portugal
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Ohshiro J, Yamamura H, Saeki T, Suzuki Y, Imaizumi Y. The multiple expression of Ca²⁺-activated Cl⁻ channels via homo- and hetero-dimer formation of TMEM16A splicing variants in murine portal vein. Biochem Biophys Res Commun 2014; 443:518-23. [PMID: 24321548 DOI: 10.1016/j.bbrc.2013.11.117] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Accepted: 11/29/2013] [Indexed: 01/16/2023]
Abstract
Ca(2+)-activated Cl(-) channel (CaCC) often plays substantial roles in the regulation of membrane excitability in smooth muscle cells (SMCs). TMEM16A, a member of the TMEM16 family, has been suggested as the molecular entity responsible for CaCC in several types of SMCs. In this study, the expression of TMEM16A splicing variants and their contribution to CaCC activity were examined in murine portal vein SMCs (mPVSMCs). Four transcripts of TMEM16A splicing variants, which include four alternatively spliced segments ("a" and "b" in N-terminus and "c" and "d" in the first intracellular loop), were identified; the expression ratio of four transcripts of "abc", "acd", "abcd" and "ac" was 64.5, 25.8, 4.8 and 4.8%, respectively. The immunostaining of isolated mPVSMCs with anti-TMEM16A antibody indicates the abundant expression of TMEM16A on the cell membrane. CaCC currents recorded in mPVSMCs were markedly reduced by T16A(inh)-A01, a specific TMEM16A inhibitor. When the two major TMEM16A splicing variants, abc and acd isoforms, were expressed separately in HEK293 cells, the CaCC currents, which possess similar electrophysiological characteristics to those in mPVSMCs were observed. The single-molecule photobleaching analyses using total internal reflection fluorescence (TIRF) microscope indicated that the distribution of stepwise photobleaching events was fit well with a binomial distribution for homodimer. Additionally, the heterodimer formation was suggested by fluorescence resonance energy transfer (FRET) analyses in HEK293 cells co-expressing CFP- or YFP-tagged variants. In conclusion, alternatively spliced variants of TMEM16A abc and acd in mPVSMCs are two major molecular entities of CaCC and may form hetero-/homo-dimers to be functional as CaCC in the regulation of membrane excitability and contractility in mPVSMCs.
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Han S, Kim K, Thakkar N, Kim D, Lee W. Role of hypoxia inducible factor-1α in the regulation of the cancer-specific variant of organic anion transporting polypeptide 1B3 (OATP1B3), in colon and pancreatic cancer. Biochem Pharmacol 2013; 86:816-23. [PMID: 23924606 DOI: 10.1016/j.bcp.2013.07.020] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Revised: 07/21/2013] [Accepted: 07/23/2013] [Indexed: 01/29/2023]
Abstract
Organic anion transporting polypeptide 1B3 (OATP1B3) was initially considered to be a liver-specific transporter, mediating the uptake of a variety of endogenous and xenobiotic substances. Over the past decade, several investigations reported that OATP1B3 is also expressed across multiple types of cancers. Only recently, our laboratory and others demonstrated the identity of cancer-specific OATP1B3 variants (csOATP1B3) arising from the use of an alternative transcription initiation site, different from the wildtype (WT) OATP1B3 expressed in the normal liver. However, the mechanisms regulating the expression of csOATP1B3 remained unknown. In our current study, we investigated the role of hypoxia and the involvement of hypoxia inducible factor-1α (HIF-1α) in regulating the transcription of csOATP1B3. Our RT-PCR and immunoblotting results indicated that csOATP1B3, but not WT OATP1B3, can be induced in response to ambient or chemical hypoxia (upon exposure to 1% O₂ or cobalt chloride). Reporter assays with deletion and mutated constructs of the csOATP1B3 promoter revealed a functional hypoxia response element (HRE) located in the proximal upstream region. Constructs harboring the HRE displayed the upregulated reporter gene expression in response to hypoxia, but not when mutated. Electrophoretic mobility shift assays using a biotin-labeled csOATP1B3 promoter HRE probe indicated the binding of HIF-1α, which was blocked by an excess of unlabeled csOATP1B3 probe. Furthermore, siRNA-based knockdown of HIF-1α caused a substantial decrease in the expression level of csOATP1B3. Taken together, these findings demonstrate that the transcription of csOATP1B3 is actively engaged during hypoxia, through a commonly utilized pathway involving HIF-1α.
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Affiliation(s)
- Songhee Han
- Department of Biological Sciences, Konkuk University, Seoul 143-701, Republic of Korea
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