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Li J, Lin J, Lin JR, Farris M, Robbins L, Andrada L, Grohol B, Nong S, Liu Y. Dolutegravir Inhibits Proliferation and Motility of BT-20 Tumor Cells Through Inhibition of Human Endogenous Retrovirus Type K. Cureus 2022; 14:e26525. [PMID: 35936147 PMCID: PMC9345775 DOI: 10.7759/cureus.26525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 07/03/2022] [Indexed: 11/25/2022] Open
Abstract
Increasing evidence points to the role of endogenous retroviruses (ERVs) in driving cancer cell proliferation. The purpose of this study was to explore the possibility of repurposing antiretroviral agents to inhibit ERVs as a new approach to cancer treatment. We found that an integrase strand-transfer inhibitor, dolutegravir (DTG), effectively inhibited the proliferation of multiple cancer cell lines and its antiproliferative potency was positively correlated with the expression levels of the human endogenous retrovirus type K (HERV-K). DTG inhibited the expression of HERV-K in multiple human cancer cell lines and the mouse mammary tumor virus (MMTV) in the murine 4T1 mammary cancer cell line. We chose the fast-growing BT-20 cell line as a model to study the in vitro antiproliferative mechanisms of DTG. BT-20 cells overexpressing both HERV-K env and pol genes became more resistant to DTG than cells transduced with vector alone. Knockdown of HERV-K also increased DTG resistance of BT-20 cells. The antiproliferative effect of DTG correlated with enhanced expression of E-cadherin and reduction in cell motility and invasiveness. Surprisingly, DTG stimulated expression of the env gene of MMTV in vivo and promoted metastasis of 4T1 tumor cells to the lungs. Taken together, our data support the role of ERVs in tumor development and encourage the further search for antiretroviral agents to treat malignancies in which ERVs are active.
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Olaya-Galán NN, Blume S, Tong K, Shen H, Gutierrez MF, Buehring GC. In vitro Susceptibility of Human Cell Lines Infection by Bovine Leukemia Virus. Front Microbiol 2022; 13:793348. [PMID: 35359744 PMCID: PMC8964291 DOI: 10.3389/fmicb.2022.793348] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 01/28/2022] [Indexed: 12/17/2022] Open
Abstract
Evidence of the presence of bovine leukemia virus (BLV) in human beings and its association with breast cancer has been published in the literature, proposing it as a zoonotic infection. However, not enough evidence exists about transmission pathways nor biological mechanisms in human beings. This study was aimed at gathering experimental evidence about susceptibility of human cell lines to BLV infection. Malignant and non-malignant human cell lines were co-cultured with BLV-infected FLK cells using a cell-to-cell model of infection. Infected human cell lines were harvested and cultured for 3 to 6 months to determine stability of infection. BLV detection was performed through liquid-phase PCR and visualized through in situ PCR. Seven out of nine cell lines were susceptible to BLV infection as determined by at least one positive liquid-phase PCR result in the 3-month culture period. iSLK and MCF7 cell lines were able to produce a stable infection throughout the 3-month period, with both cytoplasmic and/or nuclear BLV-DNA visualized by IS-PCR. Our results support experimental evidence of BLV infection in humans by demonstrating the susceptibility of human cells to BLV infection, supporting the hypothesis of a natural transmission from cattle to humans.
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Affiliation(s)
- Nury N Olaya-Galán
- Ph.D. Program in Biomedical and Biological Sciences, School of Medicine and Human Health, Universidad del Rosario, Bogotá, Colombia.,Grupo de Enfermedades Infecciosas, Laboratorio de Virología, Departamento de Microbiología, Pontificia Universidad Javeriana, Bogotá, Colombia
| | - Skyler Blume
- School of Public Health, University of California, Berkeley, Berkeley, CA, United States
| | - Kan Tong
- School of Public Health, University of California, Berkeley, Berkeley, CA, United States
| | - HuaMin Shen
- School of Public Health, University of California, Berkeley, Berkeley, CA, United States
| | - Maria F Gutierrez
- Grupo de Enfermedades Infecciosas, Laboratorio de Virología, Departamento de Microbiología, Pontificia Universidad Javeriana, Bogotá, Colombia
| | - Gertrude C Buehring
- School of Public Health, University of California, Berkeley, Berkeley, CA, United States
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Balasubramaniam M, Pandhare J, Dash C. Immune Control of HIV. JOURNAL OF LIFE SCIENCES (WESTLAKE VILLAGE, CALIF.) 2019; 1:4-37. [PMID: 31468033 PMCID: PMC6714987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The human immunodeficiency virus (HIV) infection of the immune cells expressing the cluster of differentiation 4 cell surface glycoprotein (CD4+ cells) causes progressive decline of the immune system and leads to the acquired immunodeficiency syndrome (AIDS). The ongoing global HIV/AIDS pandemic has already claimed over 35 million lives. Even after 37 years into the epidemic, neither a cure is available for the 37 million people living with HIV (PLHIV) nor is a vaccine discovered to avert the millions of new HIV infections that continue to occur each year. If left untreated, HIV infection typically progresses to AIDS and, ultimately, causes death in a majority of PLHIV. The recommended combination antiretroviral therapy (cART) suppresses virus replication and viremia, prevents or delays progression to AIDS, reduces transmission rates, and lowers HIV-associated mortality and morbidity. However, because cART does not eliminate HIV, and an enduring pool of infected resting memory CD4+ T cells (latent HIV reservoir) is established early on, any interruption to cART leads to a relapse of viremia and disease progression. Hence, strict adherence to a life-long cART regimen is mandatory for managing HIV infection in PLHIV. The HIV-1-specific cytotoxic T cells expressing the CD8 glycoprotein (CD8+ CTL) limit the virus replication in vivo by recognizing the viral antigens presented by human leukocyte antigen (HLA) class I molecules on the infected cell surface and killing those cells. Nevertheless, CTLs fail to durably control HIV-1 replication and disease progression in the absence of cART. Intriguingly, <1% of cART-naive HIV-infected individuals called elite controllers/HIV controllers (HCs) exhibit the core features that define a HIV-1 "functional cure" outcome in the absence of cART: durable viral suppression to below the limit of detection, long-term non-progression to AIDS, and absence of viral transmission. Robust HIV-1-specific CTL responses and prevalence of protective HLA alleles associated with enduring HIV-1 control have been linked to the HC phenotype. An understanding of the molecular mechanisms underlying the CTL-mediated suppression of HIV-1 replication and disease progression in HCs carrying specific protective HLA alleles may yield promising insights towards advancing the research on HIV cure and prophylactic HIV vaccine.
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Affiliation(s)
- Muthukumar Balasubramaniam
- Center for AIDS Health Disparities Research, Meharry Medical College, Nashville, TN – 37208. USA
- Department of Biochemistry and Cancer Biology, Meharry Medical College, Nashville, TN – 37208. USA
| | - Jui Pandhare
- Center for AIDS Health Disparities Research, Meharry Medical College, Nashville, TN – 37208. USA
- School of Graduate Studies and Research, Meharry Medical College, Nashville, TN – 37208. USA
| | - Chandravanu Dash
- Center for AIDS Health Disparities Research, Meharry Medical College, Nashville, TN – 37208. USA
- Department of Biochemistry and Cancer Biology, Meharry Medical College, Nashville, TN – 37208. USA
- School of Graduate Studies and Research, Meharry Medical College, Nashville, TN – 37208. USA
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Abstract
Integration of the reverse-transcribed viral cDNA into the host's genome is a critical step in the lifecycle of all retroviruses. Retrovirus integration is carried out by integrase (IN), a virus-encoded enzyme that forms an oligomeric 'intasome' complex with both ends of the linear viral DNA to catalyze their concerted insertions into the backbones of the host's DNA. IN also forms a complex with host proteins, which guides the intasome to the host's chromosome. Recent structural studies have revealed remarkable diversity as well as conserved features among the architectures of the intasome assembly from different genera of retroviruses. This chapter will review how IN oligomerizes to achieve its function, with particular focus on alpharetrovirus including the avian retrovirus Rous sarcoma virus. Another chapter (Craigie) will focus on the structure and function of IN from HIV-1.
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Affiliation(s)
- Duane P Grandgenett
- Saint Louis University Health Sciences Center, Department of Microbiology and Immunology, Institute for Molecular Virology, Doisy Research Center, St. Louis, MO, USA
| | - Hideki Aihara
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA.
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Pandey KK, Bera S, Shi K, Aihara H, Grandgenett DP. A C-terminal "Tail" Region in the Rous Sarcoma Virus Integrase Provides High Plasticity of Functional Integrase Oligomerization during Intasome Assembly. J Biol Chem 2017; 292:5018-5030. [PMID: 28184005 PMCID: PMC5377814 DOI: 10.1074/jbc.m116.773382] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 02/07/2017] [Indexed: 01/14/2023] Open
Abstract
The retrovirus integrase (IN) inserts the viral cDNA into the host DNA genome. Atomic structures of five different retrovirus INs complexed with their respective viral DNA or branched viral/target DNA substrates have indicated these intasomes are composed of IN subunits ranging from tetramers, to octamers, or to hexadecamers. IN precursors are monomers, dimers, or tetramers in solution. But how intasome assembly is controlled remains unclear. Therefore, we sought to unravel the functional mechanisms in different intasomes. We produced kinetically stabilized Rous sarcoma virus (RSV) intasomes with human immunodeficiency virus type 1 strand transfer inhibitors that interact simultaneously with IN and viral DNA within intasomes. We examined the ability of RSV IN dimers to assemble two viral DNA molecules into intasomes containing IN tetramers in contrast to one possessing IN octamers. We observed that the last 18 residues of the C terminus ("tail" region) of IN (residues 1-286) determined whether an IN tetramer or octamer assembled with viral DNA. A series of truncations of the tail region indicated that these 18 residues are critical for the assembly of an intasome containing IN octamers but not for an intasome containing IN tetramers. The C-terminally truncated IN (residues 1-269) produced an intasome that contained tetramers but failed to produce an intasome with octamers. Both intasomes have similar catalytic activities. The results suggest a high degree of plasticity for functional multimerization and reveal a critical role of the C-terminal tail region of IN in higher order oligomerization of intasomes, potentially informing future strategies to prevent retroviral integration.
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Affiliation(s)
- Krishan K Pandey
- From the Department of Microbiology and Immunology, Institute for Molecular Virology, Saint Louis University, St. Louis, Missouri 63104 and
| | - Sibes Bera
- From the Department of Microbiology and Immunology, Institute for Molecular Virology, Saint Louis University, St. Louis, Missouri 63104 and
| | - Ke Shi
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455
| | - Hideki Aihara
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455
| | - Duane P Grandgenett
- From the Department of Microbiology and Immunology, Institute for Molecular Virology, Saint Louis University, St. Louis, Missouri 63104 and
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Grawenhoff J, Engelman AN. Retroviral integrase protein and intasome nucleoprotein complex structures. World J Biol Chem 2017; 8:32-44. [PMID: 28289517 PMCID: PMC5329712 DOI: 10.4331/wjbc.v8.i1.32] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 12/24/2016] [Accepted: 01/14/2017] [Indexed: 02/05/2023] Open
Abstract
Retroviral replication proceeds through the integration of a DNA copy of the viral RNA genome into the host cellular genome, a process that is mediated by the viral integrase (IN) protein. IN catalyzes two distinct chemical reactions: 3’-processing, whereby the viral DNA is recessed by a di- or trinucleotide at its 3’-ends, and strand transfer, in which the processed viral DNA ends are inserted into host chromosomal DNA. Although IN has been studied as a recombinant protein since the 1980s, detailed structural understanding of its catalytic functions awaited high resolution structures of functional IN-DNA complexes or intasomes, initially obtained in 2010 for the spumavirus prototype foamy virus (PFV). Since then, two additional retroviral intasome structures, from the α-retrovirus Rous sarcoma virus (RSV) and β-retrovirus mouse mammary tumor virus (MMTV), have emerged. Here, we briefly review the history of IN structural biology prior to the intasome era, and then compare the intasome structures of PFV, MMTV and RSV in detail. Whereas the PFV intasome is characterized by a tetrameric assembly of IN around the viral DNA ends, the newer structures harbor octameric IN assemblies. Although the higher order architectures of MMTV and RSV intasomes differ from that of the PFV intasome, they possess remarkably similar intasomal core structures. Thus, retroviral integration machineries have adapted evolutionarily to utilize disparate IN elements to construct convergent intasome core structures for catalytic function.
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The benefits of integration. Clin Microbiol Infect 2017; 22:324-332. [PMID: 27107301 DOI: 10.1016/j.cmi.2016.02.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2016] [Revised: 02/21/2016] [Accepted: 02/21/2016] [Indexed: 01/06/2023]
Abstract
Retroviruses, including the human immunodeficiency virus (HIV), are notorious for two essential steps of their viral replication: reverse transcription and integration. This latter property is considered to be essential for productive replication and ensures the stable long-term insertion of the viral genome sequence in the host chromatin, thereby leading to the life-long association of the virus with the infected cell. Using HIV as a prototypic example, the present review aims to provide an overview of how and where integration occurs, as well as presenting general consequences for both the virus and the infected host.
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Galilee M, Britan-Rosich E, Griner SL, Uysal S, Baumgärtel V, Lamb DC, Kossiakoff AA, Kotler M, Stroud RM, Marx A, Alian A. The Preserved HTH-Docking Cleft of HIV-1 Integrase Is Functionally Critical. Structure 2016; 24:1936-1946. [PMID: 27692964 DOI: 10.1016/j.str.2016.08.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 08/19/2016] [Accepted: 08/19/2016] [Indexed: 02/06/2023]
Abstract
HIV-1 integrase (IN) catalyzes viral DNA integration into the host genome and facilitates multifunctional steps including virus particle maturation. Competency of IN to form multimeric assemblies is functionally critical, presenting an approach for anti-HIV strategies. Multimerization of IN depends on interactions between the distinct subunit domains and among the flanking protomers. Here, we elucidate an overlooked docking cleft of IN core domain that anchors the N-terminal helix-turn-helix (HTH) motif in a highly preserved and functionally critical configuration. Crystallographic structure of IN core domain in complex with Fab specifically targeting this cleft reveals a steric overlap that would inhibit HTH-docking, C-terminal domain contacts, DNA binding, and subsequent multimerization. While Fab inhibits in vitro IN integration activity, in vivo it abolishes virus particle production by specifically associating with preprocessed IN within Gag-Pol and interfering with early cytosolic Gag/Gag-Pol assemblies. The HTH-docking cleft may offer a fresh hotspot for future anti-HIV intervention strategies.
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Affiliation(s)
- Meytal Galilee
- Department of Biology, Technion - Israel Institute of Technology, Haifa 320003, Israel
| | - Elena Britan-Rosich
- Department of Immunology and Pathology, The Lautenberg Center for General and Tumor Immunology, The Hebrew University Hadassah Medical School, Jerusalem 91120, Israel
| | - Sarah L Griner
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Serdar Uysal
- Department of Biophysics, Bezmialem Vakif University, Istanbul 34093, Turkey
| | - Viola Baumgärtel
- Physical Chemistry, Department of Chemistry, Nanosystem Initiative Munich (NIM), Center for Integrated Protein Science Munich (CiPSM), Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Munich 81377, Germany
| | - Don C Lamb
- Physical Chemistry, Department of Chemistry, Nanosystem Initiative Munich (NIM), Center for Integrated Protein Science Munich (CiPSM), Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Munich 81377, Germany
| | - Anthony A Kossiakoff
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL 60637, USA
| | - Moshe Kotler
- Department of Immunology and Pathology, The Lautenberg Center for General and Tumor Immunology, The Hebrew University Hadassah Medical School, Jerusalem 91120, Israel
| | - Robert M Stroud
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Ailie Marx
- Department of Biology, Technion - Israel Institute of Technology, Haifa 320003, Israel
| | - Akram Alian
- Department of Biology, Technion - Israel Institute of Technology, Haifa 320003, Israel.
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Knyazhanskaya ES, Shadrina OA, Anisenko AN, Gottikh MB. Role of DNA-dependent protein kinase in the HIV-1 replication cycle. Mol Biol 2016. [DOI: 10.1134/s0026893316040075] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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