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Kumar A, Kuhn LT, Balbach J. A Cu 2+ complex induces the aggregation of human papillomavirus oncoprotein E6 and stabilizes p53. FEBS J 2018; 285:3013-3025. [PMID: 29931810 DOI: 10.1111/febs.14591] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 05/14/2018] [Accepted: 06/20/2018] [Indexed: 12/13/2022]
Abstract
Papillomavirus oncoprotein E6 is a critical factor in the modulation of cervical cancer in humans. At the molecular level, formation of the E6-E6AP-p53 ternary complex, which directs p53's degradation, is the key instigator of cancer transforming properties. Herein, a Cu2+ anthracenyl-terpyridine complex is described which specifically induces the aggregation of E6 in vitro and in cultured cells. For a hijacking mechanism, both E6 and E6AP are required for p53 ubiquitination and degradation. The Cu2+ complex interacts with E6 at the E6AP and p53 binding sites. We show that E6 function is suppressed by aggregation, rendering it incapable of hijacking p53 and thus increasing its cellular level. Therapeutic treatments of cervical cancer are currently unavailable to infected individuals. We anticipate that this Cu2+ complex might open up a new therapeutic avenue for the design and development of new chemical entities for the diagnosis and treatment of HPV-induced cancers.
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Affiliation(s)
- Amit Kumar
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, UK.,Institute of Physics, Biophysics, Martin-Luther-University Halle-Wittenberg, Germany.,Institute of Technical Biochemistry e.V., Martin-Luther-University Halle-Wittenberg, Germany
| | - Lars T Kuhn
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, UK
| | - Jochen Balbach
- Institute of Physics, Biophysics, Martin-Luther-University Halle-Wittenberg, Germany.,Institute of Technical Biochemistry e.V., Martin-Luther-University Halle-Wittenberg, Germany
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Niu G, Wang D, Pei Y, Sun L. Systematic identification of key genes and pathways in the development of invasive cervical cancer. Gene 2017; 618:28-41. [DOI: 10.1016/j.gene.2017.03.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 02/13/2017] [Accepted: 03/16/2017] [Indexed: 11/30/2022]
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Human Papillomavirus Vaccine. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2015; 101:231-322. [DOI: 10.1016/bs.apcsb.2015.08.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Malecka KA, Fera D, Schultz DC, Hodawadekar S, Reichman M, Donover PS, Murphy ME, Marmorstein R. Identification and characterization of small molecule human papillomavirus E6 inhibitors. ACS Chem Biol 2014; 9:1603-12. [PMID: 24854633 PMCID: PMC4145632 DOI: 10.1021/cb500229d] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Cervical cancer is the sixth most common cancer in women worldwide and the leading cause of women's death in developing countries. Nearly all cervical cancers are associated with infection of the human papillomavirus (HPV). This sexually transmitted pathogen disrupts the cell cycle via two oncoproteins: E6 and E7. Cells respond to E7-mediated degradation of pRB by upregulating the p53 tumor suppressor pathway. However, E6 thwarts this response by binding to the cellular E6-Associating Protein (E6AP) and targeting p53 for degradation. These two virus-facilitated processes pave the way for cellular transformation. Prophylactic HPV vaccines are available, but individuals already infected with HPV lack drug-based therapeutic options. To fill this void, we sought to identify small molecule inhibitors of the E6-E6AP interaction. We designed an ELISA-based high throughput assay to rapidly screen compound libraries, and hits were confirmed in several orthogonal biochemical and cell-based assays. Over 88,000 compounds were screened; 30 had in vitro potencies in the mid-nanomolar to mid-micromolar range and were classified as validated hits. Seven of these hits inhibited p53 degradation in cell lines with HPV-integrated genomes. Two compounds of similar scaffold successfully blocked p53 degradation and inhibited cell proliferation in cells stably transfected with E6. Together, these studies suggest that small molecules can successfully block E6-dependent p53 degradation and restore p53 activity. The compounds identified here constitute attractive starting points for further medicinal chemistry efforts and development into beneficial therapeutics.
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Affiliation(s)
| | - Daniela Fera
- The Wistar Institute, Philadelphia, Pennsylvania 19104, United States
| | - David C. Schultz
- The Wistar Institute, Philadelphia, Pennsylvania 19104, United States
| | | | - Melvin Reichman
- Lankenau
Institute for Medical Research, Chemical Genomics Center, Wynnewood, Pennsylvania 19096, United States
| | - Preston S. Donover
- Lankenau
Institute for Medical Research, Chemical Genomics Center, Wynnewood, Pennsylvania 19096, United States
| | - Maureen E. Murphy
- The Wistar Institute, Philadelphia, Pennsylvania 19104, United States
| | - Ronen Marmorstein
- The Wistar Institute, Philadelphia, Pennsylvania 19104, United States
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Ruthenium oligonucleotides, targeting HPV16 E6 oncogene, inhibit the growth of cervical cancer cells under illumination by a mechanism involving p53. Gene Ther 2012; 20:435-43. [PMID: 22809997 DOI: 10.1038/gt.2012.54] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
High-risk Human Papillomaviruses (HPV) has been found to be associated with carcinomas of the cervix, penis, vulva/vagina, anus, mouth and oro-pharynx. As the main tumorigenic effects of the HPV have been attributed to the expression of E6 and E7 genes, different gene therapy approaches have been directed to block their expression such as antisense oligonucleotides (ASO), ribozymes and small interfering RNAs. In order to develop a gene-specific therapy for HPV-related cancers, we investigated a potential therapeutic strategy of gene silencing activated under illumination. Our aim according to this antisense therapy consisted in regulating the HPV16 E6 oncogene by using an E6-ASO derivatized with a polyazaaromatic ruthenium (Ru(II)) complex (E6-Ru-ASO) able, under visible illumination, to crosslink irreversibly the targeted sequence. We examined the effects of E6-Ru-ASO on the expression of E6 and on the cell growth of cervical cancer cells. We demonstrated using HPV16(+) SiHa cervical cancer cells that E6-Ru-ASO induces after illumination, a reactivation of p53, the most important target of E6, as well as the inhibition of cell proliferation with a selective repression of E6 at the protein level. These results suggest that E6-Ru ASOs, activated under illumination and specifically targeting E6, are capable of inhibiting HPV16(+) cervical cancer cell proliferation.
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Toscano-Garibay JD, Benítez-Hess ML, Alvarez-Salas LM. Isolation and characterization of an RNA aptamer for the HPV-16 E7 oncoprotein. Arch Med Res 2011; 42:88-96. [PMID: 21565620 DOI: 10.1016/j.arcmed.2011.02.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2010] [Accepted: 02/03/2011] [Indexed: 11/19/2022]
Abstract
BACKGROUND AND AIMS Cervical cancer is a common neoplastic disease affecting women worldwide. Expression of human papillomavirus type 16 (HPV-16) E6/E7 genes is frequently associated with cervical cancer, representing ideal targets for diagnostic and therapeutic strategies. Aptamers are oligonucleotide ligands capable of binding with high affinity and specificity to relevant markers in therapeutics and disease detection. The aim of the study was to isolate an RNA aptamer specific for the HPV-16 E7 protein. METHODS Aptamers were selected from a randomized oligonucleotide library using a modified SELEX method and recombinant HPV-16 E7 protein. Isolated aptamers were cloned and sequenced for in silico analysis. Interaction and electromobility shift assays (EMSA) were performed to establish aptamer specificity and affinity for E7. RNase footprinting and serial deletions of the aptamer and the E7 protein were made to characterize the aptamer-protein complex. Sandwich slot-blot assays were used for K(D) determination. RESULTS After several rounds of SELEX, an aptamer (G5α3N.4) exhibited specificity for E7 using cell-free and protein extracts. G5α3N.4 binding yielded a K(D) comparable to aptamers directed to other small targets. Enzymatic and genetic analysis of G5α3N.4 binding showed a secondary structure with two stem-loop domains joined by single-stranded region contacting E7 in a clamp-like manner. The G5α3N.4 aptamer also produced specific complexes in HPV-positive cervical carcinoma cells. CONCLUSIONS The affinity and specificity of G5α3N.4 binding domains for the HPV-16 E7 protein may be used for the detection of papillomavirus infection and cervical cancer.
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Affiliation(s)
- Julia D Toscano-Garibay
- Laboratorio de Terapia Génica, Departamento de Genética y Biología Molecular, CINVESTAV, Mexico, D.F., Mexico
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López JA, Alvarez-Salas LM. Differential effects of miR-34c-3p and miR-34c-5p on SiHa cells proliferation apoptosis, migration and invasion. Biochem Biophys Res Commun 2011; 409:513-9. [PMID: 21600876 DOI: 10.1016/j.bbrc.2011.05.036] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Accepted: 05/06/2011] [Indexed: 11/28/2022]
Abstract
MicroRNAs (miRNA) regulate expression of several genes associated with human cancer. Here, we analyzed the function of miR-34c, an effector of p53, in cervical carcinoma cells. Expression of either miR-34c-3p or miR-34c-5p mimics caused inhibition of cell proliferation in the HPV-containing SiHa cells but not in other cervical cells irrespective of tumorigenicity and HPV content. These results suggest that SiHa cells may lack of regulatory mechanisms for miR-34c. Monolayer proliferation results showed that miR-34c-3p produced a more pronounced inhibitory effect although both miRNAs caused inhibition of anchorage independent growth at similar extent. However, ectopic expression of pre-miR-34c-3p, but not pre-miR-34c-5p, caused S-phase arrest in SiHa cells triggering a strong dose-dependent apoptosis. A significant inhibition was observed only for miR-34c-3p on SiHa cells migration and invasion, therefore implying alternative regulatory pathways and targets. These results suggest differential tumor suppressor roles for miR-34c-3p and miR-34c-5p and provide new insights in the understanding of miRNA biology.
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Affiliation(s)
- Jesús Adrián López
- Laboratorio de Terapia Génica, Departamento de Genética y Biología Molecular, CINVESTAV, Av. IPN 2508, México 07360 DF, Mexico
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Abstract
Deoxyribozymes (DXZs) are catalytic oligodeoxynucleotides capable of performing diverse functions including the specific cleavage of a target RNA. These molecules represent a new type of therapeutic oligonucleotides combining the efficiency of ribozymes and the intracellular endurance and simplicity of modified antisense oligonucleotides. Commonly used DXZs include the 8-17 and 10-23 motifs, which have been engineered to destroy disease-associated genes with remarkable efficiency. Targeting DXZs to disease-associated transcripts requires extensive biochemical testing to establish target RNA accessibility, catalytic efficiency, and nuclease sensibility. The usage of modified nucleotides to render nuclease-resistance DXZs must be counterweighted against deleterious consequences on catalytic activity. Further intracellular testing is required to establish the effect of microenvironmental conditions on DXZ activity and off-target issues. Application of modified DXZs to cervical cancer results in specific growth inhibition, cell death, and apoptosis. Thus, DXZs represent a highly effective antisense moiety with minimal secondary effects.
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Aquino-Jarquin G, Rojas-Hernández R, Alvarez-Salas LM. Design and function of triplex hairpin ribozymes. Methods Mol Biol 2010; 629:323-38. [PMID: 20387159 DOI: 10.1007/978-1-60761-657-3_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
Triplex ribozymes allow for the individual activity of multiple trans-acting ribozymes producing higher target cleavage relative to tandem-expressed RZs. A triplex expression system based on a single hairpin ribozyme for the multiple expression (multiplex) vectors can be engineered to target RNAs with single or multiple antisense-accessible sites. System construction relies on triplex expression modules consisting of hairpin ribozyme cassettes flanked by ribozymes lacking catalytic domains. Multiplex vectors can be generated with single or multiple specificity by tandem cloning of triplex expression modules. Triplex ribozymes are initially tested in vitro using cis- and trans-cleavage assays against radioactive-labeled targets. In addition, triplex ribozymes are tested for cis and trans cleavage in vivo by transfection in cultured cells followed by ribonuclease protection assays (RPAs) and RT-PCR. The use of triplex configurations with multiplex ribozymes will provide the basis for the development of future RZ-based therapies and technologies.
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Reyes-Gutiérrez P, Alvarez-Salas LM. Cleavage of HPV-16 E6/E7 mRNA Mediated by Modified 10–23 Deoxyribozymes. Oligonucleotides 2009; 19:233-42. [DOI: 10.1089/oli.2009.0193] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Pablo Reyes-Gutiérrez
- Laboratorio de Terapia Génica, Departamento de Genética y Biología Molecular, CINVESTAV, México City, México
| | - Luis M. Alvarez-Salas
- Laboratorio de Terapia Génica, Departamento de Genética y Biología Molecular, CINVESTAV, México City, México
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