1
|
Wu Z, Liu X, Xie F, Ma C, Lam EWF, Kang N, Jin D, Yan J, Jin B. Comprehensive pan-cancer analysis identifies the RNA-binding protein LRPPRC as a novel prognostic and immune biomarker. Life Sci 2024; 343:122527. [PMID: 38417544 DOI: 10.1016/j.lfs.2024.122527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 01/25/2024] [Accepted: 02/21/2024] [Indexed: 03/01/2024]
Abstract
AIMS RNA-binding proteins (RBPs) play pivotal roles in carcinogenesis and immunotherapy. Leucine-rich pentapeptide repeat-containing protein (LRPPRC) is crucial for RNA polyadenylation, transport, and stability. Although recent studies have suggested LRPPRC's potential role in tumor progression, its significance in tumor prognosis, diagnosis, and immunology remains unclear. MAIN METHODS We comprehensively analyzed LRPPRC expression in tumors using various databases, including Human Transcriptome Cell Atlas (HTCA), University of California Santa Cruz (UCSC), Human Protein Atlas (HPA), Sangerbox, TISIDB, GeneMANIA, GSCALite, and CellMiner. We examined the correlation between LRPPRC expression level and prognosis, immune infiltration, immunotherapy, methylation, biological function, and drug sensitivity. Single-cell analysis was performed using Tumor Immune Single Cell Hub (TISCH) and CancerSEA software. Patients with acute myeloid leukemia (AML) were categorized based on LRPPRC levels for functional and immune infiltration analyses. The role of LRPPRC in cancer was validated using in vitro experiments. KEY FINDINGS Our findings revealed that LRPPRC was highly expressed in almost all cancer types, indicating its significant prognostic and diagnostic potential. Notably, LRPPRC was associated with diverse immune features, such as immune cell infiltration, immune checkpoint genes, tumor mutational burden, and microsatellite instability, suggesting its value in guiding immunotherapy strategies. Within AML, the high-expression group had lower levels of immune cells, including CD8+ T cells. In vitro experiments confirmed the inhibitory effects of LRPPRC knockdown on AML cell proliferation. SIGNIFICANCE This study highlights LRPPRC as a reliable pan-cancer prognostic and immune biomarker, particularly in AML. It lays the groundwork for future research on LRPPRC-targeted cancer therapies.
Collapse
Affiliation(s)
- Zheng Wu
- Institute of Cancer Stem Cell, Liaoning Key Laboratory of Nucleic Acid Biology, Dalian Medical University, Dalian 116044, Liaoning, China; Department of Hematology, Liaoning Key Laboratory of Hematopoietic Stem Cell Transplantation and Translational Medicine, Liaoning Medical Center for Hematopoietic Stem Cell Transplantation, Dalian Key Laboratory of Hematology, Diamond Bay Institute of Hematology, The Second Hospital of Dalian Medical University, Dalian 116027, Liaoning, China
| | - Xinyue Liu
- Institute of Cancer Stem Cell, Liaoning Key Laboratory of Nucleic Acid Biology, Dalian Medical University, Dalian 116044, Liaoning, China
| | - Fang Xie
- Department of Hematology, Liaoning Key Laboratory of Hematopoietic Stem Cell Transplantation and Translational Medicine, Liaoning Medical Center for Hematopoietic Stem Cell Transplantation, Dalian Key Laboratory of Hematology, Diamond Bay Institute of Hematology, The Second Hospital of Dalian Medical University, Dalian 116027, Liaoning, China
| | - Chao Ma
- Institute of Cancer Stem Cell, Liaoning Key Laboratory of Nucleic Acid Biology, Dalian Medical University, Dalian 116044, Liaoning, China
| | - Eric W-F Lam
- Department of Surgery and Cancer, Imperial College London, London W12 0NN, UK
| | - Ning Kang
- Institute of Cancer Stem Cell, Liaoning Key Laboratory of Nucleic Acid Biology, Dalian Medical University, Dalian 116044, Liaoning, China
| | - Di Jin
- Institute of Cancer Stem Cell, Liaoning Key Laboratory of Nucleic Acid Biology, Dalian Medical University, Dalian 116044, Liaoning, China.
| | - Jinsong Yan
- Department of Hematology, Liaoning Key Laboratory of Hematopoietic Stem Cell Transplantation and Translational Medicine, Liaoning Medical Center for Hematopoietic Stem Cell Transplantation, Dalian Key Laboratory of Hematology, Diamond Bay Institute of Hematology, The Second Hospital of Dalian Medical University, Dalian 116027, Liaoning, China.
| | - Bilian Jin
- Institute of Cancer Stem Cell, Liaoning Key Laboratory of Nucleic Acid Biology, Dalian Medical University, Dalian 116044, Liaoning, China.
| |
Collapse
|
2
|
Yang Y, Yuan H, Zhao L, Guo S, Hu S, Tian M, Nie Y, Yu J, Zhou C, Niu J, Wang G, Song Y. Targeting the miR-34a/LRPPRC/MDR1 axis collapse the chemoresistance in P53 inactive colorectal cancer. Cell Death Differ 2022; 29:2177-2189. [PMID: 35484333 PMCID: PMC9613927 DOI: 10.1038/s41418-022-01007-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 04/11/2022] [Accepted: 04/11/2022] [Indexed: 11/09/2022] Open
Abstract
P53 mutation is an important cause of chemoresistance in colorectal cancer (CRC). The investigation and identification of the downstream targets and underlying molecular mechanism of chemoresistance induced by P53 abnormalities are therefore of great clinical significance. In this study, we demonstrated and reported for the first time that leucine-rich pentatricopeptide repeat-containing protein (LRPPRC) is a key functional downstream factor and therapeutic target for P53 mutation-induced chemoresistance. Due to its RNA binding function, LRPPRC specifically bound to the mRNA of multidrug resistance 1 (MDR1), increasing MDR1 mRNA stability and protein expression. In normal cells, P53 induced by chemotherapy inhibited the expression of LRPPRC via miR-34a and in turn reduced the expression of MDR1. However, chemotherapy-induced P53/miR-34a/LRPPRC/MDR1 signalling pathway activation was lost when P53 was mutated. Additionally, the accumulated LRPPRC and MDR1 promoted drug resistance. Most importantly, gossypol-acetic acid (GAA) was recently reported by our team as the first specific inhibitor of LRPPRC. In CRC cells with P53 mutation, GAA effectively induced degradation of the LRPPRC protein and reduced chemoresistance. Both in vivo and in vitro experiments revealed that combination chemotherapy with GAA and 5-fluorouracil (5FU) yielded improved treatment outcomes. In this study, we reported a novel mechanism and target related to P53-induced drug resistance and provided corresponding interventional strategies for the precision treatment of CRC.
Collapse
Affiliation(s)
- Yang Yang
- Key Laboratory of Cancer and Microbiome, State Key Laboratory of Molecular Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China
- The Third Hospital of Hebei Medical University, Shijiazhuang, 050051, China
- Department of General Surgery, The Fourth Hospital of Hebei Medical University, Shijiazhuang, 050051, China
| | - Hongyu Yuan
- Key Laboratory of Cancer and Microbiome, State Key Laboratory of Molecular Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China
| | - Lianmei Zhao
- Research center, The Fourth Hospital of Hebei Medical University, Shijiazhuang, 050011, China
| | - Shichao Guo
- Key Laboratory of Cancer and Microbiome, State Key Laboratory of Molecular Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China
| | - Sijun Hu
- State Key Laboratory of Cancer Biology, National Clinical Research Center for Digestive Diseases and Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an, 710000, China
| | - Miaomiao Tian
- State Key Laboratory of Cancer Biology, National Clinical Research Center for Digestive Diseases and Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an, 710000, China
| | - Yongzhan Nie
- State Key Laboratory of Cancer Biology, National Clinical Research Center for Digestive Diseases and Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an, 710000, China
| | - Jiarui Yu
- Key Laboratory of Cancer and Microbiome, State Key Laboratory of Molecular Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China
| | - Chaoxi Zhou
- The Third Hospital of Hebei Medical University, Shijiazhuang, 050051, China
| | - Jian Niu
- The Third Hospital of Hebei Medical University, Shijiazhuang, 050051, China
| | - Guiying Wang
- The Third Hospital of Hebei Medical University, Shijiazhuang, 050051, China.
- Department of General Surgery, The Fourth Hospital of Hebei Medical University, Shijiazhuang, 050051, China.
| | - Yongmei Song
- Key Laboratory of Cancer and Microbiome, State Key Laboratory of Molecular Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China.
| |
Collapse
|
3
|
Chen G, Zheng Q, Dai J, Liu J, Yin J, Xu X, Chen A, Ren L. Reduction-sensitive mixed micelles based on mPEG-SS-PzLL /TPGS to enhance anticancer efficiency of doxorubicin. REACT FUNCT POLYM 2022. [DOI: 10.1016/j.reactfunctpolym.2022.105242] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
|
4
|
Cui J, Wang L, Ren X, Zhang Y, Zhang H. LRPPRC: A Multifunctional Protein Involved in Energy Metabolism and Human Disease. Front Physiol 2019; 10:595. [PMID: 31178748 PMCID: PMC6543908 DOI: 10.3389/fphys.2019.00595] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Accepted: 04/26/2019] [Indexed: 12/26/2022] Open
Abstract
The pentatricopeptide repeat (PPR) family plays a major role in RNA stability, regulation, processing, splicing, translation, and editing. Leucine-rich PPR-motif-containing protein (LRPPRC), a member of the PPR family, is a known gene mutation that causes Leigh syndrome French-Canadian. Recently, growing evidence has pointed out that LRPPRC dysregulation is related to various diseases ranging from tumors to viral infections. This review presents available published data on the LRPPRC protein function and its role in tumors and other diseases. As a multi-functional protein, LRPPRC regulates a myriad of biological processes, including energy metabolism and maturation and the export of nuclear mRNA. Overexpression of LRPPRC has been observed in various human tumors and is associated with poor prognosis. Downregulation of LRPPRC inhibits growth and invasion, induces apoptosis, and overcomes drug resistance in tumor cells. In addition, LRPPRC plays a potential role in Parkinson's disease, neurofibromatosis 1, viral infections, and venous thromboembolism. Further investigating these new functions of LRPPRC should provide novel opportunities for a better understanding of its pathological role in diseases from tumors to viral infections and as a potential biomarker and molecular target for disease treatment.
Collapse
Affiliation(s)
- Jie Cui
- Department of Oncology, The First Affiliated Hospital, Xi'an Medical University, Xi'an, China.,College of General Practitioners, Xi'an Medical University, Xi'an, China
| | - Li Wang
- Department of Oncology, The First Affiliated Hospital, Xi'an Medical University, Xi'an, China.,College of General Practitioners, Xi'an Medical University, Xi'an, China
| | - Xiaoyue Ren
- Department of Oncology, The First Affiliated Hospital, Xi'an Medical University, Xi'an, China.,College of General Practitioners, Xi'an Medical University, Xi'an, China
| | - Yamin Zhang
- Department of Oncology, The First Affiliated Hospital, Xi'an Medical University, Xi'an, China.,College of General Practitioners, Xi'an Medical University, Xi'an, China
| | - Hongyi Zhang
- College of General Practitioners, Xi'an Medical University, Xi'an, China.,Department of Urology, The First Affiliated Hospital, Xi'an Medical University, Xi'an, China
| |
Collapse
|
5
|
Vijay N, Chande A. A hypothetical new role for single-stranded DNA binding proteins in the immune system. Immunobiology 2018; 223:671-676. [DOI: 10.1016/j.imbio.2018.07.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 06/25/2018] [Accepted: 07/05/2018] [Indexed: 12/21/2022]
|
6
|
Corrêa S, Binato R, Du Rocher B, Ferreira G, Cappelletti P, Soares-Lima S, Pinto LF, Mencalha A, Abdelhay E. ABCB1 regulation through LRPPRC is influenced by the methylation status of the GC -100 box in its promoter. Epigenetics 2014; 9:1172-83. [PMID: 25089713 DOI: 10.4161/epi.29675] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
One of the potential mechanisms of imatinib mesylate (IM) resistance in chronic myeloid leukemia (CML) is increased level of P-glycoprotein (Pgp). Pgp is an efflux pump capable of activating the multidrug resistance (MDR) phenotype. The gene encoding Pgp (ABCB1) has several binding sites in its promoter region, along with CpG islands and GC boxes, involved in its epigenetic control. In previous work, we performed a proteomic study to identify proteins involved in IM cross-resistance in acute leukemia. Among these proteins, we identified LRPPRC as a potential regulator of ABCB1 transcription via an invMED1 binding site in ABCB1. Interestingly, this invMED1 binding site overlaps with the GC -100 box. In this work, we investigated the potential role of LRPPRC in the regulation of ABCB1 transcriptional activity in CML resistance. In addition, we evaluated the potential connection between this regulation and the methylation status of the ABCB1 promoter in its GC -100 box. Our results show that LRPPRC binds prominently to the ABCB1 promoter in Lucena cells, an IM-resistant cell line. Luciferase assays showed that ABCB1 transcription is positively regulated by LRPPRC upon its knockdown. Pyrosequencing analysis showed that the ABCB1 promoter is differentially methylated at its GC -100 box in K562 cells compared with Lucena cells, and in CML patients with different response to IM. Chromatin immunoprecipitation and Pgp expression after DNA demethylation treatment showed that LRPPRC binding is affected by the methylation status of ABCB1 GC -100 box. Taken together, our findings indicate that LRPPRC is a transcription factor related to ABCB1 expression and highlight the importance of epigenetic regulation in CML resistance.
Collapse
Affiliation(s)
- Stephany Corrêa
- Laboratório Célula-Tronco - CEMO; INCA; Rio de Janeiro, Brazil
| | - Renata Binato
- Laboratório Célula-Tronco - CEMO; INCA; Rio de Janeiro, Brazil
| | | | - Gerson Ferreira
- Laboratório Célula-Tronco - CEMO; INCA; Rio de Janeiro, Brazil
| | | | | | | | - André Mencalha
- Universidade do Estado do Rio de Janeiro; UERJ; Rio de Janeiro, Brazil
| | - Eliana Abdelhay
- Laboratório Célula-Tronco - CEMO; INCA; Rio de Janeiro, Brazil
| |
Collapse
|
7
|
Philiponnet A, Grange JD, Baggetto LG. [Application of gene therapy to oncologic ophthalmology]. J Fr Ophtalmol 2014; 37:155-65. [PMID: 24503203 DOI: 10.1016/j.jfo.2013.12.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Revised: 12/03/2013] [Accepted: 12/06/2013] [Indexed: 10/25/2022]
Abstract
Since the discovery of the structure of DNA in 1953 by Watson and Crick, our understanding of the genetic causes and the regulations involved in tumor development have hugely increased. The important amount of research developed since then has led to the development of gene therapy, which specifically targets and treats cancer cells by interacting with, and correcting their genetic material. This study is a review of the most accomplished research using gene therapy aimed at treating malignant ophthalmologic diseases, and focuses more specifically on uveal melanoma and retinoblastoma. Such approaches are remarkable regarding the efficiency and the cellular targeting specificity. However, gene therapy-based treatments are so recent that many long-term interrogations subsist. The majority of the reviewed studies are conducted in vitro or in murine models, thereby requiring several years before the resulting therapies become part of the daily ophthalmologists' arsenal. However, the recent spectacular developments based on advanced scientific knowledge justify an up-to-date review that would benefit the ophthalmologist community.
Collapse
Affiliation(s)
- A Philiponnet
- Clinique ophtalmologique universitaire, hôpital de la Croix-Rousse, 103, Grande-rue-de-la-Croix-Rousse, 69317 Lyon cedex 04, France
| | - J-D Grange
- Clinique ophtalmologique universitaire, hôpital de la Croix-Rousse, 103, Grande-rue-de-la-Croix-Rousse, 69317 Lyon cedex 04, France
| | - L G Baggetto
- UMR5305, laboratoire de biologie tissulaire & ingénierie thérapeutique (LBTI), CNRS UCBL, 7, Passage-du-Vercors, 69367 Lyon cedex 07, France.
| |
Collapse
|
8
|
Schweitzer CJ, Matthews JM, Madson CJ, Donnellan MR, Cerny RL, Belshan M. Knockdown of the cellular protein LRPPRC attenuates HIV-1 infection. PLoS One 2012; 7:e40537. [PMID: 22808186 PMCID: PMC3395635 DOI: 10.1371/journal.pone.0040537] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Accepted: 06/12/2012] [Indexed: 01/28/2023] Open
Abstract
HIV-1 exploits numerous host cellular pathways for productive infection. To identify novel factors involved in HIV-1 replication, HIV-1 integrase and matrix protein complexes were captured at 4 hours post infection for proteomic analysis using an affinity purification system. Leucine-rich PPR-motif containing (LRPPRC) protein, a cellular protein involved in mitochondrial function, cell metabolism, and cell-cycle progression was identified as one of the candidate HIV-1 factors. Co-immunoprecipitation RT-PCR experiments confirmed that LRPPRC associated with HIV-1 nucleic acids during the early steps of virus infection. To establish if LRPPRC was critical for HIV-1 infection, three independent LRPPRC knockdown cell lines were constructed (2.7, 3.6, and 4.1). Subcellular fractionation of these cell lines revealed differential knockdown of LRPPRC in subcellular compartments. LRPPRC was knocked down in the insoluble/cytoskeletal fractions of all three cell lines, but the 3.6 and 4.1 cells also showed a reduction in nuclear LRPPRC. Additionally, several cellular factors were downregulated and/or disrupted by loss of LRPPRC. HIV-1 infection was reduced in all three cell lines, but virus production and RNA encapsidation were unaffected, suggesting that LRPPRC was critical for the afferent stage of virus replication. Two of the three cell lines (3.6, 4.1) were refractory for murine leukemia virus infection, a virus dependent on cellular proliferation for productive infection. Consistent with this, these two cell lines exhibited reduced cellular growth with no loss of cellular viability or change in cell cycle phenotype. The early steps of virus infection were also differentially affected among the cell lines. A reduced level of preintegration complex formation was observed in all three cell lines, but viral DNA nuclear import was reduced only in the 3.6 and 4.1 cells. Combined, these data identify LRPPRC as a HIV-1 factor that is involved in HIV-1 replication through more than one mechanism.
Collapse
Affiliation(s)
- Cameron J. Schweitzer
- Department of Medical Microbiology and Immunology, Creighton University School of Medicine, Omaha, Nebraska, United States of America
| | - John M. Matthews
- Department of Medical Microbiology and Immunology, Creighton University School of Medicine, Omaha, Nebraska, United States of America
| | - Christian J. Madson
- Department of Medical Microbiology and Immunology, Creighton University School of Medicine, Omaha, Nebraska, United States of America
| | - Meghan R. Donnellan
- Department of Medical Microbiology and Immunology, Creighton University School of Medicine, Omaha, Nebraska, United States of America
| | - Ronald L. Cerny
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America
- The Nebraska Center for Virology, Lincoln, Nebraska, United States of America
| | - Michael Belshan
- Department of Medical Microbiology and Immunology, Creighton University School of Medicine, Omaha, Nebraska, United States of America
- The Nebraska Center for Virology, Lincoln, Nebraska, United States of America
- * E-mail:
| |
Collapse
|
9
|
A comparative proteomic study identified LRPPRC and MCM7 as putative actors in imatinib mesylate cross-resistance in Lucena cell line. Proteome Sci 2012; 10:23. [PMID: 22458888 PMCID: PMC3361502 DOI: 10.1186/1477-5956-10-23] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2011] [Accepted: 03/30/2012] [Indexed: 11/23/2022] Open
Abstract
Background Although chronic myeloid leukemia (CML) treatment has improved since the introduction of imatinib mesylate (IM), cases of resistance have been reported. This resistance has been associated with the emergence of multidrug resistance (MDR) phenotype, as a BCR-ABL independent mechanism. The classic pathway studied in MDR promotion is ATP-binding cassette (ABC) family transporters expression, but other mechanisms that drive drug resistance are largely unknown. To better understand IM therapy relapse due to the rise of MDR, we compared the proteomic profiles of K562 and Lucena (K562/VCR) cells. Results The use of 2-DE coupled with a MS approach resulted in the identification of 36 differentially expressed proteins. Differential mRNA levels of leucine-rich PPR motif-containing (LRPPRC) protein, minichromosome maintenance complex component 7 (MCM7) and ATP-binding cassette sub-family B (MDR/TAP) member 1 (ABCB1) were capable of defining samples from CML patients as responsive or resistant to therapy. Conclusions Through the data presented in this work, we show the relevance of MDR to IM therapy. In addition, our proteomic approach identified candidate actors involved in resistance, which could lead to additional information on BCR-ABL-independent molecular mechanisms.
Collapse
|
10
|
Liu L, Sanosaka M, Lei S, Bestwick ML, Frey JH, Surovtseva YV, Shadel GS, Cooper MP. LRP130 protein remodels mitochondria and stimulates fatty acid oxidation. J Biol Chem 2011; 286:41253-41264. [PMID: 21971050 PMCID: PMC3308838 DOI: 10.1074/jbc.m111.276121] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Revised: 09/21/2011] [Indexed: 11/06/2022] Open
Abstract
Impaired oxidative phosphorylation (OXPHOS) is implicated in several metabolic disorders. Even though mitochondrial DNA encodes several subunits critical for OXPHOS, the metabolic consequence of activating mitochondrial transcription remains unclear. We show here that LRP130, a protein involved in Leigh syndrome, increases hepatic β-fatty acid oxidation. Using convergent genetic and biochemical approaches, we demonstrate LRP130 complexes with the mitochondrial RNA polymerase to activate mitochondrial transcription. Activation of mitochondrial transcription is associated with increased OXPHOS activity, increased supercomplexes, and denser cristae, independent of mitochondrial biogenesis. Consistent with increased oxidative phosphorylation, ATP levels are increased in both cells and mouse liver, whereas coupled respiration is increased in cells. We propose activation of mitochondrial transcription remodels mitochondria and enhances oxidative metabolism.
Collapse
Affiliation(s)
- Lijun Liu
- Division of Cardiovascular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Masato Sanosaka
- Division of Cardiovascular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Shi Lei
- Division of Cardiovascular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Megan L Bestwick
- Departments of Pathology and Genetics, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Joseph H Frey
- Division of Cardiovascular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Yulia V Surovtseva
- Departments of Pathology and Genetics, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Gerald S Shadel
- Departments of Pathology and Genetics, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Marcus P Cooper
- Division of Cardiovascular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605.
| |
Collapse
|
11
|
Bratic A, Wredenberg A, Grönke S, Stewart JB, Mourier A, Ruzzenente B, Kukat C, Wibom R, Habermann B, Partridge L, Larsson NG. The bicoid stability factor controls polyadenylation and expression of specific mitochondrial mRNAs in Drosophila melanogaster. PLoS Genet 2011; 7:e1002324. [PMID: 22022283 PMCID: PMC3192837 DOI: 10.1371/journal.pgen.1002324] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2011] [Accepted: 08/04/2011] [Indexed: 11/18/2022] Open
Abstract
The bicoid stability factor (BSF) of Drosophila melanogaster has been reported to be present in the cytoplasm, where it stabilizes the maternally contributed bicoid mRNA and binds mRNAs expressed from early zygotic genes. BSF may also have other roles, as it is ubiquitously expressed and essential for survival of adult flies. We have performed immunofluorescence and cell fractionation analyses and show here that BSF is mainly a mitochondrial protein. We studied two independent RNAi knockdown fly lines and report that reduced BSF protein levels lead to a severe respiratory deficiency and delayed development at the late larvae stage. Ubiquitous knockdown of BSF results in a severe reduction of the polyadenylation tail lengths of specific mitochondrial mRNAs, accompanied by an enrichment of unprocessed polycistronic RNA intermediates. Furthermore, we observed a significant reduction in mRNA steady state levels, despite increased de novo transcription. Surprisingly, mitochondrial de novo translation is increased and abnormal mitochondrial translation products are present in knockdown flies, suggesting that BSF also has a role in coordinating the mitochondrial translation in addition to its role in mRNA maturation and stability. We thus report a novel function of BSF in flies and demonstrate that it has an important intra-mitochondrial role, which is essential for maintaining mtDNA gene expression and oxidative phosphorylation. The majority of the cellular energy currency ATP is formed in a tubular network, termed mitochondria, present within virtually all eukaryotic cells. The mitochondria are unique among cellular organelles in that they contain their own genome, which encodes critical proteins necessary for cellular energy production. However, the vast majority of mitochondrial proteins are encoded in the nucleus and imported into mitochondria. Gene expression thus needs to be coordinated between the two genomes to ensure efficient mitochondrial function and sufficient adaptation to different physiological demands. The regulation of the mitochondrial genome is poorly understood, with many of the basic regulators not yet being characterized. We used RNAi in the fruit fly to study the in vivo function of the bicoid stability factor (BSF), previously thought to be a cytoplasmic and nuclear protein important for fly development. We show here that BSF is mainly localized to mitochondria, where it is essential for mtDNA gene expression, regulating the polyadenylation and maturation of specific mRNAs. Furthermore, BSF coordinates the translation and assembly of mitochondrial peptides in the inner mitochondrial membrane.
Collapse
Affiliation(s)
- Ana Bratic
- Department of Laboratory Medicine, Karolinska Institutet, Solna, Sweden
- Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Anna Wredenberg
- Max Planck Institute for Biology of Ageing, Cologne, Germany
| | | | | | - Arnaud Mourier
- Max Planck Institute for Biology of Ageing, Cologne, Germany
| | | | - Christian Kukat
- Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Rolf Wibom
- Department of Laboratory Medicine, Karolinska Institutet, Solna, Sweden
| | | | - Linda Partridge
- Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Nils-Göran Larsson
- Department of Laboratory Medicine, Karolinska Institutet, Solna, Sweden
- Max Planck Institute for Biology of Ageing, Cologne, Germany
- * E-mail:
| |
Collapse
|
12
|
Miller DS, Bauer B, Hartz AMS. Modulation of P-glycoprotein at the blood-brain barrier: opportunities to improve central nervous system pharmacotherapy. Pharmacol Rev 2008; 60:196-209. [PMID: 18560012 DOI: 10.1124/pr.107.07109] [Citation(s) in RCA: 246] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Pharmacotherapy of central nervous system (CNS) disorders (e.g., neurodegenerative diseases, epilepsy, brain cancer, and neuro-AIDS) is limited by the blood-brain barrier. P-glycoprotein, an ATP-driven, drug efflux transporter, is a critical element of that barrier. High level of expression, luminal membrane location, multispecificity, and high transport potency make P-glycoprotein a selective gatekeeper of the blood-brain barrier and thus a primary obstacle to drug delivery into the brain. As such, P-glycoprotein limits entry into the CNS for a large number of prescribed drugs, contributes to the poor success rate of CNS drug candidates, and probably contributes to patient-to-patient variability in response to CNS pharmacotherapy. Modulating P-glycoprotein could therefore improve drug delivery into the brain. Here we review the current understanding of signaling mechanisms responsible for the modulation of P-glycoprotein activity/expression at the blood-brain barrier with an emphasis on recent studies from our laboratories. Using intact brain capillaries from rats and mice, we have identified multiple extracellular and intracellular signals that regulate this transporter; several signaling pathways have been mapped. Three pathways are triggered by elements of the brain's innate immune response, one by glutamate, one by xenobiotic-nuclear receptor (pregnane X receptor) interactions, and one by elevated beta-amyloid levels. Signaling is complex, with several pathways sharing common signaling elements [tumor necrosis factor (TNF) receptor 1, endothelin (ET) B receptor, protein kinase C, and nitric-oxide synthase), suggesting a regulatory network. Several pathways include autocrine/paracrine elements, involving release of the proinflammatory cytokine, TNF-alpha, and the polypeptide hormone, ET-1. Finally, several steps in signaling are potential therapeutic targets that could be used to modulate P-glycoprotein activity in the clinic.
Collapse
Affiliation(s)
- David S Miller
- Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA.
| | | | | |
Collapse
|
13
|
Abstract
The recent discovery of new potent therapeutic molecules which do not reach the clinic due to poor delivery and low bioavailability have made the delivery of molecules a keystone in therapeutic development. Several technologies have been designed to improve cellular uptake of therapeutic molecules, including CPPs (cell-penetrating peptides), which represent a new and innovative concept to bypass the problem of bioavailability of drugs. CPPs constitute very promising tools and have been successfully applied for in vivo. Two CPP strategies have been described to date; the first one requires chemical linkage between the drug and the carrier for cellular drug internalization, and the second is based on the formation of stable complexes with drugs, depending on their chemical nature. The Pep and MPG families are short amphipathic peptides, which form stable nanoparticles with proteins and nucleic acids respectively. MPG- and Pep-based nanoparticles enter cells independently of the endosomal pathway and efficiently deliver cargoes, in a fully biologically active form, into a large variety of cell lines, as well as in animal models. This review focuses on the structure-function relationship of non-covalent MPG and Pep-1 strategies, and their requirement for cellular uptake of biomolecules and applications in cultured cells and animal models.
Collapse
|
14
|
De Renzis S, Elemento O, Tavazoie S, Wieschaus EF. Unmasking activation of the zygotic genome using chromosomal deletions in the Drosophila embryo. PLoS Biol 2007; 5:e117. [PMID: 17456005 PMCID: PMC1854917 DOI: 10.1371/journal.pbio.0050117] [Citation(s) in RCA: 212] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2006] [Accepted: 02/28/2007] [Indexed: 11/19/2022] Open
Abstract
During the maternal-to-zygotic transition, a developing embryo integrates post-transcriptional regulation of maternal mRNAs with transcriptional activation of its own genome. By combining chromosomal ablation in Drosophila with microarray analysis, we characterized the basis of this integration. We show that the expression profile for at least one third of zygotically active genes is coupled to the concomitant degradation of the corresponding maternal mRNAs. The embryo uses transcription and degradation to generate localized patterns of expression, and zygotic transcription to degrade distinct classes of maternal transcripts. Although degradation does not appear to involve a simple regulatory code, the activation of the zygotic genome starts from intronless genes sharing a common cis-element. This cis-element interacts with a single protein, the Bicoid stability factor, and acts as a potent enhancer capable of timing the activity of an exogenous transactivator. We propose that this regulatory mode links morphogen gradients with temporal regulation during the maternal-to-zygotic transition.
Collapse
Affiliation(s)
- Stefano De Renzis
- Howard Hughes Medical Institute, Department of Molecular Biology, Princeton University, New Jersey, United States of America
- * To whom correspondence should be addressed. E-mail: (SDR); (EFW)
| | - Olivier Elemento
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
| | - Saeed Tavazoie
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
| | - Eric F Wieschaus
- Howard Hughes Medical Institute, Department of Molecular Biology, Princeton University, New Jersey, United States of America
- * To whom correspondence should be addressed. E-mail: (SDR); (EFW)
| |
Collapse
|
15
|
Sarkadi B, Homolya L, Szakács G, Váradi A. Human multidrug resistance ABCB and ABCG transporters: participation in a chemoimmunity defense system. Physiol Rev 2006; 86:1179-236. [PMID: 17015488 DOI: 10.1152/physrev.00037.2005] [Citation(s) in RCA: 536] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
In this review we give an overview of the physiological functions of a group of ATP binding cassette (ABC) transporter proteins, which were discovered, and still referred to, as multidrug resistance (MDR) transporters. Although they indeed play an important role in cancer drug resistance, their major physiological function is to provide general protection against hydrophobic xenobiotics. With a highly conserved structure, membrane topology, and mechanism of action, these essential transporters are preserved throughout all living systems, from bacteria to human. We describe the general structural and mechanistic features of the human MDR-ABC transporters and introduce some of the basic methods that can be applied for the analysis of their expression, function, regulation, and modulation. We treat in detail the biochemistry, cell biology, and physiology of the ABCB1 (MDR1/P-glycoprotein) and the ABCG2 (MXR/BCRP) proteins and describe emerging information related to additional ABCB- and ABCG-type transporters with a potential role in drug and xenobiotic resistance. Throughout this review we demonstrate and emphasize the general network characteristics of the MDR-ABC transporters, functioning at the cellular and physiological tissue barriers. In addition, we suggest that multidrug transporters are essential parts of an innate defense system, the "chemoimmunity" network, which has a number of features reminiscent of classical immunology.
Collapse
Affiliation(s)
- Balázs Sarkadi
- National Medical Center, Institute of Hematology and Immunology, Membrane Research Group, Budapest, Hungary.
| | | | | | | |
Collapse
|
16
|
Cooper MP, Qu L, Rohas LM, Lin J, Yang W, Erdjument-Bromage H, Tempst P, Spiegelman BM. Defects in energy homeostasis in Leigh syndrome French Canadian variant through PGC-1alpha/LRP130 complex. Genes Dev 2006; 20:2996-3009. [PMID: 17050673 PMCID: PMC1620022 DOI: 10.1101/gad.1483906] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2006] [Accepted: 09/08/2006] [Indexed: 11/25/2022]
Abstract
Leigh syndrome French Canadian variant (LSFC) is an autosomal recessive neurodegenerative disorder due to mutation in the LRP130 (leucine-rich protein 130 kDa) gene. Unlike classic Leigh syndrome, the French Canadian variant spares the heart, skeletal muscle, and kidneys, but severely affects the liver. The precise role of LRP130 in cytochrome c oxidase deficiency and hepatic lactic acidosis that accompanies this disorder is unknown. We show here that LRP130 is a component of the PGC-1alpha (peroxisome proliferator-activated receptor coactivator 1-alpha) transcriptional coactivator holocomplex and regulates expression of PEPCK (phosphoenolpyruvate carboxykinase), G6P (glucose-6-phosphatase), and certain mitochondrial genes through PGC-1alpha. Reduction of LRP130 in fasted mice via adenoviral RNA interference (RNAi) vector blocks the induction of PEPCK and G6P, and blunts hepatic glucose output. LRP130 is also necessary for PGC-1alpha-dependent transcription of several mitochondrial genes in vivo. These data link LRP130 and PGC-1alpha to defective hepatic energy homeostasis in LSFC, and reveal a novel regulatory mechanism of glucose homeostasis.
Collapse
Affiliation(s)
- Marcus P Cooper
- Dana-Farber Cancer Institute and the Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | | | | | | | | | | | | | | |
Collapse
|
17
|
Deshayes S, Morris MC, Divita G, Heitz F. Interactions of amphipathic CPPs with model membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2006; 1758:328-35. [PMID: 16277976 DOI: 10.1016/j.bbamem.2005.10.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2005] [Revised: 10/07/2005] [Accepted: 10/07/2005] [Indexed: 10/25/2022]
Abstract
We have investigated the interactions between two carrier peptides and model membrane systems as well as the conformational consequences of these interactions. Studies performed with lipid monolayers at the air-water interface have enabled identification of the nature of the lipid-peptide interactions and characterization of the influence of phospholipids on the ability of these peptides to penetrate into lipidic media. Penetration experiments reveal that both peptides interact strongly with phospholipids. Conformational investigations indicate that the lipid-peptide interaction govern the conformational state of the peptides. Based on the ability of both peptides to promote ion permeabilization of both natural and artificial membranes, we propose a model illustrating the translocation process. For MPG, it is based on the formation of a beta-barrel pore-like structure, while for Pep-1, it is based on association of helices.
Collapse
Affiliation(s)
- Sébastien Deshayes
- CRBM-CNRS, FRE 2593, 1919, Route de Mende, F-34293 Montpellier cedex, France
| | | | | | | |
Collapse
|
18
|
Labialle S, Dayan G, Michaud M, Barakat S, Rigal D, Baggetto LG. Gene therapy of the typical multidrug resistance phenotype of cancers: a new hope? Semin Oncol 2006; 32:583-90. [PMID: 16338424 DOI: 10.1053/j.seminoncol.2005.09.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The multidrug resistance (MDR) phenotype of cancers has generated a large amount of research, owing to its constant fatal clinical outcome. Many studies have focused on the discovery of chemomodulators; however, in spite of this huge effort, the side effects that these products induce, and their additive toxicity when used in the presence of anticancer drugs, have led to the disaffection of the pharmaceutical industry and possibly slowed down research in pharmacological modulation. New tools developed using molecular biology techniques have opened the way for gene therapy and given birth to new therapeutic hopes. However, these discoveries and especially their clinical applications have slowed due to a lack of knowledge of the systems that finely regulate the MDR genes. This weakness explains why, to date, no general review has focused on the possibilities of gene therapy of MDR derived form the strategic options now available. Based on molecular foundations and recent fundamental discoveries, we seek to inform clinicians of the therapeutic hopes for chemoresistant tumors brought about by potent and specific new tools such as transcriptional decoys, interfering RNAs, etc. After describing the causes and mechanisms of MDR, we critically review these new strategies and their corresponding clinical trials.
Collapse
Affiliation(s)
- Stëphane Labialle
- McGill University, Royal Victoria Hospital, Montreal, Quebec, Canada
| | | | | | | | | | | |
Collapse
|
19
|
Deshayes S, Morris MC, Divita G, Heitz F. Interactions of amphipathic carrier peptides with membrane components in relation with their ability to deliver therapeutics. J Pept Sci 2006; 12:758-65. [PMID: 17131287 DOI: 10.1002/psc.810] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
To identify rules for the design of efficient CPPs that can deliver therapeutic agents such as nucleic acids (DNAs, siRNAs) or proteins and PNAs into subcellular compartments, we compared the properties of several primary and secondary amphipathic CPPs. Studies performed with lipid monolayers at the air-water interface have enabled identification of the nature of the lipid-peptide interactions and characterization of the influence of phospholipids on the ability of these peptides to penetrate into lipidic media. Penetration and compression experiments reveal that both peptides interact strongly with phospholipids, and observations on Langmuir-Blodgett transfers indicate that they can modify the lipid organization. Conformational investigations indicate that the lipid-peptide interactions govern the conformational state(s) of the peptides. On the basis of the ability of both peptides to promote ion permeation through both natural and artificial membranes, models illustrating the translocation processes have been proposed. One is based on the formation of a beta-barrel pore-like structure while another is based on the association of helices.
Collapse
|
20
|
Abstract
MDR1 (once P-glycoprotein, now referred to as ABCB1) plays a role as a blood-brain barrier, preventing drug absorption into the brain, and is known to confer multiple drug resistance in cancer chemotherapy. MDR1 is composed of two repeated fragments, and there are six transmembrane domains (TMD) on the N-terminal of each repeat and a nucleotide (ATP) binding domain (NBD) on the C-terminal. These two repeats are dependent but cooperate as one functional molecule, with one pocket for excreting drugs. The 12 TM domains form a funnel facing the outside of cells, and NBD is in cytosol as a dimer. One NBD is composed of the Walker A, Q-loop, ABC-signature and the Walker B for phosphate binding of nucleotide. This tertiary structure of MDR1 is suggested from the structure of the NBD of histidine permease (HisP), clarified by x-ray crystallography. On the model of HisP, the NBD positions described above make a functional domain, and the same NBD structure is found on many other ABC transporters. An experiment with MDR1 gene knockout mice showed the high plasma AUC of drugs in mdr null mice [mdr1a(-/-)] and a high level in the brain, indicating that MDR1 has an efflux function (prevention of absorption) in the intestinal lumen and acts as a barrier of drug uptake in the brain, as well as has the function of urinary and biliary excretion of drugs. The transcription of MDR1 is dependent on two sites; the promoter site (-105/-100)(-245/-141) and the enhancer site (-7864/-7817). Autoantibody from autoimmune hepatitis patients weakly reacted with the extracellular peptide (aa314-aa328 between TM5 and 6) of MDR1 on the outside of the cell membrane, and did not react with peptides in the NBD and in the membrane-spanning region in TM5. There is an ambiguity about the function of MDR1 as GlcCer translocase.
Collapse
Affiliation(s)
- Takaharu Mizutani
- Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan.
| | | |
Collapse
|
21
|
Gambrelle J, Labialle S, Dayan G, Gayet L, Barakat S, Michaud M, Grange JD, Baggetto LG. [Multidrug resistance in uveal melanoma]. J Fr Ophtalmol 2005; 28:652-9. [PMID: 16141933 DOI: 10.1016/s0181-5512(05)81112-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
In spite of important progress in the local treatment of uveal melanoma, the most frequent primitive intraocular tumor, 15%-30% of patients still die because of tumor metastasis. This tumor is characterized by constitutive chemoresistance, thwarting any attempt to control it using the usual chemotherapy protocols. The chemoresistance of uveal melanoma is mainly due to the typical multidrug resistance phenotype (MDR), which is linked to overexpression of membrane proteins that actively extrude anticancer drugs from the cell. Typical MDR is particularly complex in this tumor since several chemoresistance-related proteins are simultaneously produced. The negative prognostic significance of the overexpression of P-glycoprotein, the main representative among the typical MDR-related proteins, was shown in uveal melanoma. The atypical MDR phenotype, which refers to other chemoresistance mechanisms such as resistance to apoptosis also contributes to the chemoresistance of uveal melanoma. Thanks to the recent progress in molecular biology, the chemosensitization strategies of gene therapy approaches, which aim at weakening the pathological activity of MDR genes in cancer cells, are currently on the rise. This approach will disrupt current therapeutic strategies and necessarily improve and standardize the methods used to characterize the chemoresistance profile of this cancer. Indeed, we will have to know the genes to be targeted for each melanoma in order to induce cell chemosensitivity.
Collapse
Affiliation(s)
- J Gambrelle
- Institut de Biologie et Chimie des Protéines, IBCP UMR5086 CNRS UCBL, Lyon
| | | | | | | | | | | | | | | |
Collapse
|
22
|
Liu L, Vo A, Liu G, McKeehan WL. Putative tumor suppressor RASSF1 interactive protein and cell death inducer C19ORF5 is a DNA binding protein. Biochem Biophys Res Commun 2005; 332:670-6. [PMID: 15907802 PMCID: PMC3225229 DOI: 10.1016/j.bbrc.2005.05.006] [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] [Received: 04/29/2005] [Accepted: 05/03/2005] [Indexed: 11/20/2022]
Abstract
C19ORF5 is a homologue of microtubule-associated protein MAP1B that interacts with natural paclitaxel-like microtubule stabilizer and candidate tumor suppressor RASSF1A. Although normally distributed throughout the cytosol, C19ORF5 specifically associates with microtubules stabilized by paclitaxel or RASSF1A. At sufficiently high concentrations, C19ORF5 causes mitochondrial aggregation and genome destruction (MAGD). The accumulation on hyperstabilized microtubules coupled to MAGD has been proposed to mediate tumor suppression by the taxoid drug family and RASSF1A. Here, we show that the C-terminus of C19ORF5 (C19ORF5C) interacts with mitochondria-associated DNA binding protein, LRPPRC, in liver cells. Like LRPPRC, C19ORF5 also binds DNA with an affinity and specificity sufficient to be of utility in DNA affinity chromatography to purify homogeneous recombinant C19ORF5C from bacterial extracts. Homogeneous C19ORF5 exhibited no intrinsic DNase activity. Deletion mutagenesis indicated that C19ORF5 selectively binds double stranded DNA through its microtubule binding domain. These results suggest C19ORF5 as a DNA binding protein similar to microtubule-associated proteins tau and MAP2.
Collapse
Affiliation(s)
- Leyuan Liu
- Center for Cancer Biology and Nutrition, Institute of Biosciences and Technology, Texas A&M University System Health Science Center, Houston, TX 77030-3303, USA
| | - Amy Vo
- Center for Cancer Biology and Nutrition, Institute of Biosciences and Technology, Texas A&M University System Health Science Center, Houston, TX 77030-3303, USA
| | - Guoqin Liu
- Center for Cancer Biology and Nutrition, Institute of Biosciences and Technology, Texas A&M University System Health Science Center, Houston, TX 77030-3303, USA
| | - Wallace L. McKeehan
- Center for Cancer Biology and Nutrition, Institute of Biosciences and Technology, Texas A&M University System Health Science Center, Houston, TX 77030-3303, USA
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-2128, USA
- Corresponding author. Fax: +1 713 677 7512. (W.L. McKeehan)
| |
Collapse
|
23
|
Bauer B, Hartz AMS, Fricker G, Miller DS. Modulation of p-glycoprotein transport function at the blood-brain barrier. Exp Biol Med (Maywood) 2005; 230:118-27. [PMID: 15673560 DOI: 10.1177/153537020523000206] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The central nervous system (CNS) effects of many therapeutic drugs are blunted because of restricted entry into the brain. The basis for this poor permeability is the brain capillary endothelium, which comprises the blood-brain barrier. This tissue exhibits very low paracellular (tight-junctional) permeability and expresses potent, multispecific, drug export pumps. Together, these combine to limit use of pharmacotherapy to treat CNS disorders such as brain cancer and bacterial or viral infections. Of all the xenobiotic efflux pumps highly expressed in brain capillary endothelial cells, p-glycoprotein handles the largest fraction of commonly prescribed drugs and thus is an obvious target for manipulation. Here we review recent studies focused on understanding the mechanisms by which p-glycoprotein activity in the blood-brain barrier can be modulated. These include (i) direct inhibition by specific competitors, (ii) functional modulation, and (iii) transcriptional modulation. Each has the potential to specifically reduce p-glycoprotein function and thus selectively increase brain permeability of p-glycoprotein substrates.
Collapse
Affiliation(s)
- Björn Bauer
- Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | | | | | | |
Collapse
|