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Kao TL, Huang YC, Chen YH, Baumann P, Tseng CK. LARP3, LARP7, and MePCE are involved in the early stage of human telomerase RNA biogenesis. Nat Commun 2024; 15:5955. [PMID: 39009594 PMCID: PMC11250828 DOI: 10.1038/s41467-024-50422-w] [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: 09/21/2023] [Accepted: 07/09/2024] [Indexed: 07/17/2024] Open
Abstract
Human telomerase assembly is a highly dynamic process. Using biochemical approaches, we find that LARP3 and LARP7/MePCE are involved in the early stage of human telomerase RNA (hTR) and that their binding to RNA is destabilized when the mature form is produced. LARP3 plays a negative role in preventing the processing of the 3'-extended long (exL) form and the binding of LARP7 and MePCE. Interestingly, the tertiary structure of the exL form prevents LARP3 binding and facilitates hTR biogenesis. Furthermore, low levels of LARP3 promote hTR maturation, increase telomerase activity, and elongate telomeres. LARP7 and MePCE depletion inhibits the conversion of the 3'-extended short (exS) form into mature hTR and the cytoplasmic accumulation of hTR, resulting in telomere shortening. Taken together our data suggest that LARP3 and LARP7/MePCE mediate the processing of hTR precursors and regulate the production of functional telomerase.
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Affiliation(s)
- Tsai-Ling Kao
- Department of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Yu-Cheng Huang
- Department of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Yi-Hsuan Chen
- Department of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Peter Baumann
- Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University, Mainz, Germany
- Institute of Molecular Biology, Mainz, Germany
| | - Chi-Kang Tseng
- Department of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan.
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2
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Evaluating the RIST Molecular-Targeted Regimen in a Three-Dimensional Neuroblastoma Spheroid Cell Culture Model. Cancers (Basel) 2023; 15:cancers15061749. [PMID: 36980635 PMCID: PMC10046822 DOI: 10.3390/cancers15061749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 03/06/2023] [Accepted: 03/10/2023] [Indexed: 03/16/2023] Open
Abstract
Background: The outcome for patients with high-risk neuroblastoma remains poor and novel treatment strategies are urgently needed. The RIST protocol represents a novel metronomic and multimodal treatment strategy for high-risk neuroblastoma combining molecular-targeted drugs as ‘pre-treatment’ with a conventional chemotherapy backbone, currently evaluated in a phase II clinical trial. For preclinical drug testing, cancer cell growth as spheroid compared to mo-nolayer cultures is of advantage since it reproduces a wide range of tumor characteristics, including the three-dimensional architecture and cancer stem cell (CSC) properties. The objective of this study was to establish a neuroblastoma spheroid model for the rigorous assessment of the RIST treatment protocol. Methods: Evaluation of CSC marker expression was performed by mRNA and protein analysis and spheroid viability by luminescence-based assays. Aberrant expression of RNA-binding protein La in neuroblastoma was assessed by tissue microarray analysis and patients’ data mining. Results: Spheroid cultures showed increased expression of a subgroup of CSC-like markers (CXCR4, NANOG and BMI) and higher Thr389 phosphorylation of the neuroblastoma-associated RNA-binding protein La when compared to monolayer cultures. Molecular-targeted ‘pre-treatment’ of spheroids decreased neoplastic signaling and CSC marker expression. Conclusions: The RIST treatment protocol efficiently reduced the viability of neuroblastoma spheroids characterized by advanced CSC properties.
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Upregulated SSB Is Involved in Hepatocellular Carcinoma Progression and Metastasis through the Epithelial-Mesenchymal Transition, Antiapoptosis, and Altered ROS Level Pathway. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2023; 2023:5207431. [PMID: 36785788 PMCID: PMC9922187 DOI: 10.1155/2023/5207431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 10/31/2022] [Accepted: 11/25/2022] [Indexed: 02/05/2023]
Abstract
Hepatocellular carcinoma (HCC) is one of the most common malignant tumors with high morbidity and mortality. Therefore, finding new diagnostic and therapeutic targets is vital for HCC patients. Recent studies have shown that dysregulation of RNA-binding proteins is often associated with cancer progression. Several studies have reported that the RNA-binding protein SSB can promote cancer occurrence and progression and is linked to tumor epithelial-mesenchymal transition (EMT), which could be a new diagnostic marker and therapeutic target. However, the expression and function of SSB in HCC remain to be elucidated. Therefore, this study is aimed at clarifying the expression and biological function of SSB in HCC through bioinformatics analysis combined with in vitro experiments. We found that SSB is highly expressed in HCC and is associated with the poor prognosis of HCC patients, and it can serve as an independent unfavorable prognostic factor. Knockdown of SSB can inhibit the growth of HCC cells in vitro, increase the level of apoptosis and the expression of pro-apoptosis-related proteins, and decrease the expression of antiapoptotic proteins. Meanwhile, SSB knockdown reduced HCC cell invasiveness, and the expression of EMT-related proteins changed significantly. We also found that the gene SSB was associated with the level of oxidative stress in liver cancer cells, and the level of intracellular reactive oxygen species (ROS) increased after knockdown of SSB. The results of bioinformatics analysis also showed that high expression of SSB may affect the effect of checkpoint blockade (ICB) therapy. In conclusion, we found that SSB is highly expressed in HCC and that upregulated SSB can promote the proliferation and metastasis of HCC through antiapoptotic, altered intracellular oxidative stress level, and EMT pathways, which can serve as a new diagnostic marker and therapeutic target, and patients with high SSB expression may not have obvious ICB therapy effect.
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Salomao N, Maslah N, Giulianelli A, Drevon L, Aguinaga L, Gu X, Cassinat B, Giraudier S, Fenaux P, Fahraeus R. Reduced murine double minute 2 and
4
protein, but not
messenger RNA
, expression is associated with more severe disease in myelodysplastic syndromes and acute myeloblastic leukaemia. Br J Haematol 2022; 201:234-248. [PMID: 36546586 DOI: 10.1111/bjh.18608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 12/04/2022] [Accepted: 12/05/2022] [Indexed: 12/24/2022]
Abstract
The human homologues of murine double minute 2 (MDM2) and 4 (MDM4) negatively regulate p53 tumour suppressor activity and are reported to be frequently overexpressed in human malignancies, prompting clinical trials with drugs that prevent interactions between MDM2/MDM4 and p53. Bone marrow samples from 111 patients with acute myeloblastic leukaemia, myelodysplastic syndrome or chronic myelomonocytic leukaemia were examined for protein (fluorescence-activated cell sorting) and messenger RNA (mRNA) expression (quantitative polymerase chain reaction) of MDM2, MDM4 and tumour protein p53 (TP53). Low protein expression of MDM2 and MDM4 was observed in immature cells from patients with excess of marrow blasts (>5%) compared with CD34+ /CD45low cells from healthy donors and patients without excess of marrow blasts (<5%). The mRNA levels were indistinguishable in all samples examined regardless of disease status or blast levels. Low MDM2 and MDM4 protein expression were correlated with poor survival. These data show a poor correlation between mRNA and protein expression levels, suggesting that quantitative flow cytometry analysis of protein expression levels should be used to predict and validate the efficacy of MDM2 and MDM4 inhibitors. These findings show that advanced disease is associated with reduced MDM2 and MDM4 protein expression and indicate that the utility of MDM2 and MDM4 inhibitors may have to be reconsidered in the treatment of advanced myeloid malignancies.
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Affiliation(s)
- Norman Salomao
- Inserm UMRS1131, Institut de Recherche Saint‐Louis, Institut de Génétique Moléculaire, Université de Paris‐Cité, Hôpital St. Louis Paris France
| | - Nabih Maslah
- Inserm UMRS1131, Institut de Recherche Saint‐Louis, Institut de Génétique Moléculaire, Université de Paris‐Cité, Hôpital St. Louis Paris France
| | - Anouk Giulianelli
- Service d'Hématologie Senior—Hôpital Saint‐Louis—Assistance Publique Hôpitaux de Paris, and Paris Cité university Paris France
| | - Louis Drevon
- Inserm UMRS1131, Institut de Recherche Saint‐Louis, Institut de Génétique Moléculaire, Université de Paris‐Cité, Hôpital St. Louis Paris France
- Service d'Hématologie Senior—Hôpital Saint‐Louis—Assistance Publique Hôpitaux de Paris, and Paris Cité university Paris France
| | - Lorea Aguinaga
- Inserm UMRS1131, Institut de Recherche Saint‐Louis, Institut de Génétique Moléculaire, Université de Paris‐Cité, Hôpital St. Louis Paris France
- Service d'Hématologie Senior—Hôpital Saint‐Louis—Assistance Publique Hôpitaux de Paris, and Paris Cité university Paris France
| | - Xiaolian Gu
- Department of Medical Biosciences Building 6M, Umeå University Umeå Sweden
| | - Bruno Cassinat
- Inserm UMRS1131, Institut de Recherche Saint‐Louis, Institut de Génétique Moléculaire, Université de Paris‐Cité, Hôpital St. Louis Paris France
- Service d'Hématologie Senior—Hôpital Saint‐Louis—Assistance Publique Hôpitaux de Paris, and Paris Cité university Paris France
| | - Stephane Giraudier
- Inserm UMRS1131, Institut de Recherche Saint‐Louis, Institut de Génétique Moléculaire, Université de Paris‐Cité, Hôpital St. Louis Paris France
- Service d'Hématologie Senior—Hôpital Saint‐Louis—Assistance Publique Hôpitaux de Paris, and Paris Cité university Paris France
| | - Pierre Fenaux
- Service d'Hématologie Senior—Hôpital Saint‐Louis—Assistance Publique Hôpitaux de Paris, and Paris Cité university Paris France
| | - Robin Fahraeus
- Inserm UMRS1131, Institut de Recherche Saint‐Louis, Institut de Génétique Moléculaire, Université de Paris‐Cité, Hôpital St. Louis Paris France
- Department of Medical Biosciences Building 6M, Umeå University Umeå Sweden
- RECAMO, Masaryk Memorial Cancer Institute Brno Czech Republic
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Moran H, A. Ghandhi S, Shimada N, Hubbard K. Identification of RNA Species That Bind to the hnRNP A1 in Normal and Senescent Human Fibroblasts. Physiology (Bethesda) 2022. [DOI: 10.5772/intechopen.101525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
hnRNP A1 is a member of the hnRNPs (heterogeneous nuclear ribonucleoproteins) family of proteins that play a central role in regulating genes responsible for cell proliferation, DNA repair, apoptosis, and telomere biogenesis. Previous studies have shown that hnRNPA1 had reduced protein levels and increased cytoplasmic accumulation in senescent human diploid fibroblasts. The consequence of reduced protein expression and altered cellular localization may account for the alterations in gene expression observed during senescence. There is limited information for gene targets of hnRNP A1 as well as its in vivo function. In these studies, we performed RNA co-immunoprecipitation experiments using hnRNP A1 as the target protein to identify potential mRNA species in ribonucleoprotein (RNP) complexes. Using this approach, we identified the human double minute 2 (HDM2) mRNA as a binding target for hnRNP A1 in young and senescent human diploid fibroblasts cells. It was also observed that alterations of hnRNP A1 expression modulate HDM2 mRNA levels in young IMR-90 cells. We also demonstrated that the levels of HDM2 mRNA increased with the downregulation of hnRNP A1 and decrease with the overexpression of hnRNP A1. Although we did not observe a significant decrease in HDM2 protein level, a concomitant increase in p53 protein level was detected with the overexpression of hnRNP A1. Our studies also show that hnRNP A1 directly interacts with HDM2 mRNA at a region corresponding to its 3′ UTR (untranslated region of a gene). The results from this study demonstrate that hnRNP A1 has a novel role in participating in the regulation of HDM2 gene expression.
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Huang X, Zhu J, Li Y, Yu Y, Tang J. La protein regulates protein expression by binding with the mRNAs of target genes and participates the pathological process of ovarian cancer. Front Oncol 2022; 12:763480. [PMID: 36110943 PMCID: PMC9468491 DOI: 10.3389/fonc.2022.763480] [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: 11/15/2021] [Accepted: 08/08/2022] [Indexed: 12/03/2022] Open
Abstract
Research on the mechanism and new targets of ovarian cancer is of great significance to reduce the high mortality and drug resistance of ovarian cancer. Human La protein has been found to be highly expressed in a variety of malignant tumors and plays a role in tumorigenesis and development through its RNA-binding function. However, its role and mechanism in ovarian cancer are not completely clear. The present study showed that La protein was highly expressed in serum and tissues of patients with ovarian cancer by ELISA and immunohistochemistry, and the high expression of La protein was associated with the increased degree of malignancy and poor prognosis by searching the KM plotter database. Interference of the La gene resulted in a significant decrease in the proliferation, migration, and invasion of ovarian cancer cells with growth block in the G1 phase and increasing apoptosis. By RNA binding protein immunoprecipitation, transcriptome sequencing, and proteomics, 14 downstream target genes were screened. The La protein might affect the protein expression of these 14 genes by binding with the mRNAs. Therefore, it played a role in the pathological process of ovarian cancer.
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Staudacher AH, Li Y, Liapis V, Brown MP. The RNA-binding protein La/SSB associates with radiation-induced DNA double-strand breaks in lung cancer cell lines. Cancer Rep (Hoboken) 2022; 5:e1543. [PMID: 34636174 PMCID: PMC9351668 DOI: 10.1002/cnr2.1543] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 07/13/2021] [Accepted: 08/06/2021] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Platinum-based chemotherapy and radiotherapy are standard treatments for non-small cell lung cancer, which is the commonest, most lethal cancer worldwide. As a marker of treatment-induced cancer cell death, we have developed a radiodiagnostic imaging antibody, which binds to La/SSB. La/SSB is an essential, ubiquitous ribonuclear protein, which is over expressed in cancer and plays a role in resistance to cancer therapies. AIM In this study, we examined radiation-induced DNA double strand breaks (DSB) in lung cancer cell lines and examined whether La/SSB associated with these DSB. METHOD Three lung cancer lines (A549, H460 and LL2) were irradiated with different X-ray doses or X-radiated with a 5 Gy dose and examined at different time-points post-irradiation for DNA DSB in the form of γ-H2AX and Rad51 foci. Using fluorescence microscopy, we examined whether La/SSB and γ-H2AX co-localise and performed proximity ligation assay (PLA) and co-immunoprecipitation to confirm the interaction of these proteins. RESULTS We found that the radio-resistant A549 cell line compared to the radio-sensitive H460 cell line showed faster resolution of radiation-induced γ-H2AX foci over time. Conversely, we found more co-localised γ-H2AX and La/SSB foci by PLA in irradiated A549 cells. CONCLUSION The co-localisation of La/SSB with radiation-induced DNA breaks suggests a role of La/SSB in DNA repair, however further experimentation is required to validate this.
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Affiliation(s)
- Alexander H. Staudacher
- Translational Oncology Laboratory, Centre for Cancer BiologySA Pathology and University of South AustraliaAdelaideSouth Australia5000Australia
- School of MedicineUniversity of AdelaideAdelaideSouth Australia5000Australia
| | - Yanrui Li
- Translational Oncology Laboratory, Centre for Cancer BiologySA Pathology and University of South AustraliaAdelaideSouth Australia5000Australia
| | - Vasilios Liapis
- Translational Oncology Laboratory, Centre for Cancer BiologySA Pathology and University of South AustraliaAdelaideSouth Australia5000Australia
| | - Michael P. Brown
- Translational Oncology Laboratory, Centre for Cancer BiologySA Pathology and University of South AustraliaAdelaideSouth Australia5000Australia
- School of MedicineUniversity of AdelaideAdelaideSouth Australia5000Australia
- Cancer Clinical Trials UnitRoyal Adelaide HospitalAdelaideSouth Australia5000Australia
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8
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Ma B, Feng H, Feng C, Liu Y, Zhang H, Wang J, Wang W, He P, Niu F. Kill Two Birds with One Stone: A Multifunctional Dual-Targeting Protein Drug to Overcome Imatinib Resistance in Philadelphia Chromosome-Positive Leukemia. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2104850. [PMID: 35239999 PMCID: PMC9069375 DOI: 10.1002/advs.202104850] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 01/26/2022] [Indexed: 06/07/2023]
Abstract
The Bcr/Abl plays a central role in Philadelphia chromosome-positive (Ph+) leukemia because of the constitutively activated Abl tyrosine kinase and its downstream pathways. Currently, the clinical treatment of imatinib-resistant patients with tyrosine kinase inhibitors is severely limited by drug resistance and adverse effects. Herein, a dual-targeting proteolysis-targeting chimera (PROTAC) protein drug, termed PMI Bcr/Abl-R6, is designed by engrafting an MDM2/p53 inhibition peptide sequence onto the Bcr/Abl tetramerization domain. PMI Bcr/Abl-R6, harboring a Bcr/Abl targeting sequence and an MDM2 binding sequence, acts as a PROTAC drug in Ph+ leukemia cells. Its dual-targeting constitution suggests that PMI Bcr/Abl-R6 designs to target the tetramerization domain instead of the Abl kinase domain, therefore has the potential to overcome drug resistance mutations in the kinase domain. The efficient ability of PMI Bcr/Abl-R6 is demonstrated to simultaneously induce Bcr/Abl degradation and activate the p53 pathway. PMI Bcr/Abl-R6 has the potential to overcome drug resistance in Ph+ leukemias by multiple mechanisms.
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Affiliation(s)
- Bohan Ma
- Department of UrologyThe First Affiliated HospitalXi'an Jiaotong UniversityXi'an710061China
| | - Hui Feng
- Department of HematologyThe First Affiliated Hospital of Xi'an Jiaotong UniversityXi'an710061China
| | - Chao Feng
- Department of EndocrinologyThe First Affiliated Hospital of Xi'an Jiaotong UniversityXi'an710061China
| | - Yi Liu
- Department of HematologyThe First Affiliated Hospital of Xi'an Jiaotong UniversityXi'an710061China
| | - Hailing Zhang
- Department of HematologyThe First Affiliated Hospital of Xi'an Jiaotong UniversityXi'an710061China
| | - Jincheng Wang
- Department of HematologyThe First Affiliated Hospital of Xi'an Jiaotong UniversityXi'an710061China
| | - Wenjuan Wang
- Department of HematologyThe First Affiliated Hospital of Xi'an Jiaotong UniversityXi'an710061China
| | - Pengcheng He
- Department of HematologyThe First Affiliated Hospital of Xi'an Jiaotong UniversityXi'an710061China
| | - Fan Niu
- Department of HematologyThe First Affiliated Hospital of Xi'an Jiaotong UniversityXi'an710061China
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Dun Y, Huang G, Liu J, Wei W. ImmunoPET imaging of hematological malignancies: From preclinical promise to clinical reality. Drug Discov Today 2021; 27:1196-1203. [PMID: 34838729 DOI: 10.1016/j.drudis.2021.11.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Revised: 10/22/2021] [Accepted: 11/18/2021] [Indexed: 12/23/2022]
Abstract
Immuno-positron emission tomography (immunoPET) imaging is a paradigm-shifting imaging technique for whole-body and all-lesion tumor detection, based on the combined specificity of tumor-targeting vectors [e.g., monoclonal antibodies (mAbs), nanobodies, and bispecific antibodies] and the sensitivity of PET imaging. By noninvasively, comprehensively, and serially revealing heterogeneous tumor antigen expression, immunoPET imaging is gradually improving the theranostic prospects for hematological malignancies. In this review, we summarize the available literature regarding immunoPET in imaging hematological malignancies. We also highlight the pros and cons of current conjugation strategies, and modular chemistry that can be leveraged to develop novel immunoPET probes for hematological malignancies. Lastly, we discuss the use of immunoPET imaging in guiding antibody drug development.
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Affiliation(s)
- Yiting Dun
- Department of Nuclear Medicine, Institute of Clinical Nuclear Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200217, China
| | - Gang Huang
- Department of Nuclear Medicine, Institute of Clinical Nuclear Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200217, China; Shanghai Key Laboratory of Molecular Imaging, Shanghai University of Medicine and Health Sciences, Shanghai 201318, China
| | - Jianjun Liu
- Department of Nuclear Medicine, Institute of Clinical Nuclear Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200217, China.
| | - Weijun Wei
- Department of Nuclear Medicine, Institute of Clinical Nuclear Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200217, China.
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Liapis V, Tieu W, Wittwer NL, Gargett T, Evdokiou A, Takhar P, Rudd SE, Donnelly PS, Brown MP, Staudacher AH. Positron Emission Tomographic Imaging of Tumor Cell Death Using Zirconium-89-Labeled APOMAB® Following Cisplatin Chemotherapy in Lung and Ovarian Cancer Xenograft Models. Mol Imaging Biol 2021; 23:914-928. [PMID: 34231102 PMCID: PMC8578059 DOI: 10.1007/s11307-021-01620-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 04/28/2021] [Accepted: 05/26/2021] [Indexed: 02/02/2023]
Abstract
PURPOSE Early detection of tumor treatment responses represents an unmet clinical need with no approved noninvasive methods. DAB4, or its chimeric derivative, chDAB4 (APOMAB®) is an antibody that targets the Lupus associated antigen (La/SSB). La/SSB is over-expressed in malignancy and selectively targeted by chDAB4 in cancer cells dying from DNA-damaging treatment. Therefore, chDAB4 is a unique diagnostic tool that detects dead cancer cells and thus could distinguish between treatment responsive and nonresponsive patients. PROCEDURES In clinically relevant tumor models, mice bearing subcutaneous xenografts of human ovarian or lung cancer cell lines or intraperitoneal ovarian cancer xenografts were untreated or given chemotherapy followed 24h later by chDAB4 radiolabeled with [89Zr]ZrIV. Tumor responses were monitored using bioluminescence imaging and caliper measurements. [89Zr]Zr-chDAB4 uptake in tumor and normal tissues was measured using an Albira SI Positron-Emission Tomography (PET) imager and its biodistribution was measured using a Hidex gamma-counter. RESULTS Tumor uptake of [89Zr]Zr-chDAB4 was detected in untreated mice, and uptake significantly increased in both human lung and ovarian tumors after chemotherapy, but not in normal tissues. CONCLUSION Given that tumors, rather than normal tissues, were targeted after chemotherapy, these results support the clinical development of chDAB4 as a radiodiagnostic imaging agent and as a potential predictive marker of treatment response.
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Affiliation(s)
- Vasilios Liapis
- Translational Oncology Laboratory, Centre for Cancer Biology, SA Pathology and University of South Australia, Level 9 University of South Australia Health Innovation Building, North Terrace, Adelaide, 5000, Australia.
| | - William Tieu
- School of Medicine, University of Adelaide, Adelaide, SA, 5000, Australia
- Molecular Imaging and Therapy Research Unit (MITRU), South Australian Health and Medical Research Institute (SAHMRI), Adelaide, Australia
| | - Nicole L Wittwer
- Translational Oncology Laboratory, Centre for Cancer Biology, SA Pathology and University of South Australia, Level 9 University of South Australia Health Innovation Building, North Terrace, Adelaide, 5000, Australia
| | - Tessa Gargett
- Translational Oncology Laboratory, Centre for Cancer Biology, SA Pathology and University of South Australia, Level 9 University of South Australia Health Innovation Building, North Terrace, Adelaide, 5000, Australia
| | - Andreas Evdokiou
- Discipline of Surgery, Breast Cancer Research Unit, Basil Hetzel Institute and Centre for Personalised Cancer Medicine, University of Adelaide, Woodville, SA, 5011, Australia
| | - Prab Takhar
- Molecular Imaging and Therapy Research Unit (MITRU), South Australian Health and Medical Research Institute (SAHMRI), Adelaide, Australia
| | - Stacey E Rudd
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Paul S Donnelly
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Michael P Brown
- Translational Oncology Laboratory, Centre for Cancer Biology, SA Pathology and University of South Australia, Level 9 University of South Australia Health Innovation Building, North Terrace, Adelaide, 5000, Australia
- School of Medicine, University of Adelaide, Adelaide, SA, 5000, Australia
- Cancer Clinical Trials Unit, Royal Adelaide Hospital, Adelaide, SA, 5000, Australia
| | - Alexander H Staudacher
- Translational Oncology Laboratory, Centre for Cancer Biology, SA Pathology and University of South Australia, Level 9 University of South Australia Health Innovation Building, North Terrace, Adelaide, 5000, Australia
- School of Medicine, University of Adelaide, Adelaide, SA, 5000, Australia
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11
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Bayfield MA, Vinayak J, Kerkhofs K, Mansouri-Noori F. La proteins couple use of sequence-specific and non-specific binding modes to engage RNA substrates. RNA Biol 2021; 18:168-177. [PMID: 30777481 PMCID: PMC7928037 DOI: 10.1080/15476286.2019.1582955] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 02/05/2019] [Accepted: 02/05/2019] [Indexed: 12/31/2022] Open
Abstract
La shuttles between the nucleus and cytoplasm where it binds nascent RNA polymerase III (pol III) transcripts and mRNAs, respectively. La protects the 3' end of pol III transcribed RNA precursors, such as pre-tRNAs, through the use of a well-characterized UUU-3'OH binding mode. La proteins are also RNA chaperones, and La-dependent RNA chaperone activity is hypothesized to promote pre-tRNA maturation and translation at cellular and viral internal ribosome entry sites via binding sites distinct from those used for UUU-3'OH recognition. Since the publication of La-UUU-3'OH co-crystal structures, biochemical and genetic experiments have expanded our understanding of how La proteins use UUU-3'OH-independent binding modes to make sequence-independent contacts that can increase affinity for ligands and promote RNA remodeling. Other recent work has also expanded our understanding of how La binds mRNAs through contacts to the poly(A) tail. In this review, we focus on advances in the study of La protein-RNA complex surfaces beyond the description of the La-UUU-3'OH binding mode. We highlight recent advances in the functions of expected canonical nucleic acid interaction surfaces, a heightened appreciation of disordered C-terminal regions, and the nature of sequence-independent RNA determinants in La-RNA target binding. We further discuss how these RNA binding modes may have relevance to the function of the La-related proteins.
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Affiliation(s)
- Mark A. Bayfield
- Department of Biology, York University, Toronto, Ontario, Canada
| | - Jyotsna Vinayak
- Department of Biology, York University, Toronto, Ontario, Canada
| | - Kyra Kerkhofs
- Department of Biology, York University, Toronto, Ontario, Canada
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RNA-Binding Protein La Mediates TGFβ-Induced Epithelial to Mesenchymal Transition and Cancer Stem Cell Properties. Cancers (Basel) 2021; 13:cancers13020343. [PMID: 33477794 PMCID: PMC7832410 DOI: 10.3390/cancers13020343] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 01/08/2021] [Accepted: 01/12/2021] [Indexed: 01/06/2023] Open
Abstract
Simple Summary Reversible epithelial to mesenchymal transition (EMT) plays a key role in establishing a malignant phenotype by assuring cancer cell plasticity critical for cancer progression by allowing a small fraction of cancer cells to detach from primary lesions and outgrow at metastatic sites. Cancer cell plasticity is associated with cancer stem cell properties contributing to chemoresistance, metastasis, and poor clinical outcomes. Dysregulated RNA-binding proteins are key players in controlling the RNA metabolism, including mRNA processing, export, and translation, and have been implicated in cancer cell plasticity. In this study, we demonstrated that aberrantly expressed RNA-binding protein La is critical for transforming growth factor β-induced EMT and for gaining cancer stem cell properties. Understanding the function of aberrant RNA-binding protein expression in cancer cell plasticity reveals prospects for identifying novel therapeutic targets. Abstract Background: the aberrant overexpression of predominantly nuclear localizing RNA-binding protein (RBP) La contributes to proliferation, mobility, and chemoresistance of cancer cells and tumor growth in mice. Methods: studies included cancer tissue microarrays (TMAs) analyses, cancer tissue data mining, transforming growth factor β (TGFβ)-induced cancer cell plasticity studies, three dimensional sphere growth, epithelial to mesenchymal transition (EMT) assays, analysis of cancer stem cell (CSC) marker expression, and post-translational modification of cancer-associated La protein. Results: we demonstrated that significant overexpression of RBP La in lung and head and neck cancer tissue correlates with poor overall survival. Furthermore, small interfering RNA-mediated depletion of La reduced proliferation and migration of cancer cells, blocked TGFβ-induced EMT, and diminished both EMT and CSC marker expression. Rescue experiments with La wildtype but not RNA chaperone domain activity-defective La mutant increased the expression of those cancer progression markers, suggesting a critical role of La’s RNA chaperone activity in this process. La depletion in cancer cells also significantly decreased sphere growth in the presence of TGFβ. Interestingly, TGFβ treatment induced phosphorylation of La at threonine 389 (pLaT389) only in adherents but not in 3D growing cultures. Conclusion: our study suggests that the TGFβ/AKT/pLaT389 signaling pathway regulates cancer cell plasticity.
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Liapis V, Tieu W, Rudd SE, Donnelly PS, Wittwer NL, Brown MP, Staudacher AH. Improved non-invasive positron emission tomographic imaging of chemotherapy-induced tumor cell death using Zirconium-89-labeled APOMAB®. EJNMMI Radiopharm Chem 2020; 5:27. [PMID: 33205364 PMCID: PMC7672150 DOI: 10.1186/s41181-020-00109-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Accepted: 10/19/2020] [Indexed: 01/01/2023] Open
Abstract
Purpose The chimeric monoclonal antibody (mAb) chDAB4 (APOMAB®) targets the Lupus associated (La)/Sjögren Syndrome-B (SSB) antigen, which is over-expressed in tumors but only becomes available for antibody binding in dead tumor cells. Hence, chDAB4 may be used as a novel theranostic tool to distinguish between responders and nonresponders early after chemotherapy. Here, we aimed to ascertain which positron emitter, Zirconium-89 ([89Zr]ZrIV) or Iodine-124 ([124I]I), was best suited to label chDAB4 for post-chemotherapy PET imaging of tumor-bearing mice and to determine which of two different bifunctional chelators provided optimal tumor imaging by PET using [89Zr]ZrIV-labeled chDAB4. Methods C57BL/6 J mice bearing subcutaneous syngeneic tumors of EL4 lymphoma were either untreated or given chemotherapy, then administered radiolabeled chDAB4 after 24 h with its biodistribution examined using PET and organ assay. We compared chDAB4 radiolabeled with [89Zr] ZrIV or [124I] I, or [89Zr]Zr-chDAB4 using either DFO-NCS or DFOSq as a chelator. Results After chemotherapy, [89Zr]Zr-chDAB4 showed higher and prolonged mean (± SD) tumor uptake of 29.5 ± 5.9 compared to 7.8 ± 1.2 for [124I] I -chDAB4. In contrast, antibody uptake in healthy tissues was not affected. Compared to DFO-NCS, DFOSq did not result in significant differences in tumor uptake of [89Zr]Zr-chDAB4 but did alter the tumor:liver ratio in treated mice 3 days after injection in favour of DFOSq (8.0 ± 1.1) compared to DFO-NCS (4.2 ± 0.7). Conclusion ImmunoPET using chDAB4 radiolabeled with residualizing [89Zr] ZrIV rather than [124I] I optimized post-chemotherapy tumor uptake. Further, PET imaging characteristics were improved by DFOSq rather than DFO-NCS. Therefore, the radionuclide/chelator combination of [89Zr] ZrIV and DFOSq is preferred for the imminent clinical evaluation of chDAB4 as a selective tumor cell death radioligand. Supplementary Information Supplementary information accompanies this paper at 10.1186/s41181-020-00109-6.
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Affiliation(s)
- Vasilios Liapis
- Translational Oncology Laboratory, Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA, 5000, Australia.
| | - William Tieu
- School of Medicine, University of Adelaide, Adelaide, SA, 5000, Australia.,Molecular Imaging and Therapy Research Unit (MITRU), South Australian Health and Medical Research Institute (SAHMRI), Adelaide, Australia
| | - Stacey E Rudd
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Paul S Donnelly
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Nicole L Wittwer
- Translational Oncology Laboratory, Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA, 5000, Australia
| | - Michael P Brown
- Translational Oncology Laboratory, Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA, 5000, Australia.,School of Medicine, University of Adelaide, Adelaide, SA, 5000, Australia.,Cancer Clinical Trials Unit, Royal Adelaide Hospital, Adelaide, SA, 5000, Australia
| | - Alexander H Staudacher
- Translational Oncology Laboratory, Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA, 5000, Australia.,School of Medicine, University of Adelaide, Adelaide, SA, 5000, Australia
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Kaliatsi EG, Argyriou AI, Bouras G, Apostolidi M, Konstantinidou P, Shaukat AN, Spyroulias GA, Stathopoulos C. Functional and Structural Aspects of La Protein Overexpression in Lung Cancer. J Mol Biol 2020; 432:166712. [PMID: 33197462 DOI: 10.1016/j.jmb.2020.11.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 11/09/2020] [Accepted: 11/09/2020] [Indexed: 10/23/2022]
Abstract
La is an abundant phosphoprotein that protects polymerase III transcripts from 3'-5' exonucleolytic degradation and facilitates their folding. Consisting of the evolutionary conserved La motif (LAM) and two consecutive RNA Recognition Motifs (RRMs), La was also found to bind additional RNA transcripts or RNA domains like internal ribosome entry site (IRES), through sequence-independent binding modes which are poorly understood. Although it has been reported overexpressed in certain cancer types and depletion of its expression sensitizes cancer cells to certain chemotherapeutic agents, its role in cancer remains essentially uncharacterized. Herein, we study the effects of La overexpression in A549 lung adenocarcinoma cells, which leads to increased cell proliferation and motility. Expression profiling of several transcription and translation factors indicated that La overexpression leads to downregulation of global translation through hypophosphorylation of 4E-BPs and upregulation of IRES-mediated translation. Moreover, analysis of La localization after nutrition deprivation of the transfected cells showed a normal distribution in the nucleus and nucleoli. Although the RNA binding capacity of La has been primarily linked to the synergy between the conserved LAM and RRM1 domains which act as a module, we show that recombinant stand-alone LAM can specifically bind a pre-tRNA ligand, based on binding experiments combined with NMR analysis. We propose that LAM RNA binding properties could support the expanding and diverse RNA ligand repertoire of La, thus promoting its modulatory role, both under normal and pathogenic conditions like cancer.
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Affiliation(s)
- Eleni G Kaliatsi
- Department of Biochemistry, School of Medicine, University of Patras, 26504 Patras, Greece
| | | | - Georgios Bouras
- Department of Pharmacy, University of Patras, 26504 Patras, Greece
| | - Maria Apostolidi
- Department of Biochemistry, School of Medicine, University of Patras, 26504 Patras, Greece
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Huang X, Tang J. Human La Protein: An RNA-Binding Protein Involved in Ovarian Cancer Development and Multidrug Resistance. Onco Targets Ther 2020; 13:10721-10727. [PMID: 33132701 PMCID: PMC7592153 DOI: 10.2147/ott.s269983] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 09/04/2020] [Indexed: 12/18/2022] Open
Abstract
Multidrug resistance is the main cause of chemotherapy failure and death in patients with advanced ovarian cancer. Drug resistance is a problem that must be solved to improve the survival rate of patients with advanced ovarian cancer. The RNA-binding protein La and the La-related protein family are highly expressed in various malignant tumors, including ovarian cancer. This article reviews the mechanisms of La protein in tumorigenesis, development, and drug resistance. High La protein expression in tumor cells promotes tumor proliferation, invasion, and migration; disrupts cell cycle; and inhibits tumor cell apoptosis caused by chemotherapeutic drugs through various pathways, resulting in chemotherapy resistance in ovarian cancer. Further study of the role of La protein in ovarian cancer multidrug resistance may be conducive to the development of human La protein-specific inhibitors that suppress ovarian cancer drug resistance.
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Affiliation(s)
- Xuan Huang
- Department of Pharmacy, Obstetrics & Gynecology Hospital of Fudan University, Shanghai 200011, People's Republic of China
| | - Jing Tang
- Department of Pharmacy, Obstetrics & Gynecology Hospital of Fudan University, Shanghai 200011, People's Republic of China
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Kang D, Lee Y, Lee JS. RNA-Binding Proteins in Cancer: Functional and Therapeutic Perspectives. Cancers (Basel) 2020; 12:cancers12092699. [PMID: 32967226 PMCID: PMC7563379 DOI: 10.3390/cancers12092699] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 09/17/2020] [Accepted: 09/18/2020] [Indexed: 12/12/2022] Open
Abstract
Simple Summary RNA-binding proteins (RBPs) play central roles in regulating posttranscriptional expression of genes. Many of them are known to be deregulated in a wide variety of cancers. Dysregulated RBPs influence the expression levels of target RNAs related to cancer phenotypes, such as proliferation, apoptosis, angiogenesis, senescence, and EMT/invasion/metastasis. Thus, understanding the molecular functions of RBPs and their roles in cancer-related phenotypes can lead to improved therapeutic strategies. Abstract RNA-binding proteins (RBPs) crucially regulate gene expression through post-transcriptional regulation, such as by modulating microRNA (miRNA) processing and the alternative splicing, alternative polyadenylation, subcellular localization, stability, and translation of RNAs. More than 1500 RBPs have been identified to date, and many of them are known to be deregulated in cancer. Alterations in the expression and localization of RBPs can influence the expression levels of oncogenes, tumor-suppressor genes, and genome stability-related genes. RBP-mediated gene regulation can lead to diverse cancer-related cellular phenotypes, such as proliferation, apoptosis, angiogenesis, senescence, and epithelial-mesenchymal transition (EMT)/invasion/metastasis. This regulation can also be associated with cancer prognosis. Thus, RBPs can be potential targets for the development of therapeutics for the cancer treatment. In this review, we describe the molecular functions of RBPs, their roles in cancer-related cellular phenotypes, and various approaches that may be used to target RBPs for cancer treatment.
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Affiliation(s)
- Donghee Kang
- Medical Research Center, College of Medicine, Inha University, Incheon 22212, Korea; (D.K.); (Y.L.)
- Department of Molecular Medicine, College of Medicine, Inha University, Incheon 22212, Korea
- Program in Biomedical Science & Engineering, Inha University Graduate School, Incheon 22212, Korea
| | - Yerim Lee
- Medical Research Center, College of Medicine, Inha University, Incheon 22212, Korea; (D.K.); (Y.L.)
- Department of Molecular Medicine, College of Medicine, Inha University, Incheon 22212, Korea
| | - Jae-Seon Lee
- Medical Research Center, College of Medicine, Inha University, Incheon 22212, Korea; (D.K.); (Y.L.)
- Department of Molecular Medicine, College of Medicine, Inha University, Incheon 22212, Korea
- Program in Biomedical Science & Engineering, Inha University Graduate School, Incheon 22212, Korea
- Correspondence: ; Tel.: +82-32-860-9832
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Examination of clinically-derived p210 BCR/ABL1 RhoGEF mutations in a murine bone marrow transplantation model of CML. Leuk Res 2020; 97:106440. [PMID: 32892149 DOI: 10.1016/j.leukres.2020.106440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 07/30/2020] [Accepted: 08/20/2020] [Indexed: 11/22/2022]
Abstract
Expression of the p210 BCR/ABL1 fusion protein has been described in virtually all patients with chronic myelogenous leukemia (CML). Previous studies have identified a guanine nucleotide exchange factor (RhoGEF) domain within BCR that is retained in p210 BCR/ABL1. Missense mutations at residues T654 (T654K) and F547 (F547L) within this domain have been reported in a CML patient in blast crisis (BC). In this study, we have evaluated p210 BCR/ABL1 constructs that contain these substitutions in a murine bone marrow transplantation (BMT) model of CML. The mutants exhibit normal expression and tyrosine kinase activity but altered signaling. When examined in the BMT assay, mice that express the mutants exhibit earlier onset of disease but have significantly extended lifespans relative to mice that express unmodified p210 BCR/ABL1. While mice that express p210 BCR/ABL1 exhibit neutrophilia that progresses to a less differentiated phenotype at death, disease in the mutant mice is characterized by eosinophilia with no maturation arrest. This observation was confirmed in vitro using myeloid cells and was associated with enhanced p53 phosphorylation and G1/S arrest. These results suggest that residues within the RhoGEF domain of p210 BCR/ABL1 can influence disease progression.
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Pan J, Tong S, Kong L, Zhu J, Tang J. La protein contributes to cells proliferation and migration and serves as a potential therapeutic target for hepatocellular carcinoma. Asia Pac J Clin Oncol 2020; 16:e228-e235. [PMID: 32780941 DOI: 10.1111/ajco.13370] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 04/28/2020] [Indexed: 01/09/2023]
Abstract
AIM La protein is a multifunctional RNA-binding protein involved in RNA metabolism that has been reported to promote the growth of some solid tumors. However, potential role of La in hepatocellular carcinoma (HCC) has not been fully elucidated. This study aimed to investigate the expression of La and its function in HCC. METHODS Quantitative real-time polymerase chain reaction (qRT-PCR) and western blot analysis were conducted to detect the expression levels of La mRNA and protein in HCC cells and tissues. The proliferation capability of cells was clarified by Cell Counting Kit-8 and clone formation assays. Wound healing assay was carried out to assess cell migration ability. Related protein expressions were also analyzed by western blot. RESULTS Analysis of our clinical samples showed that La mRNA and protein expression of HCC tissues was higher than those of corresponding adjacent tissues, consistent with the result of microarray datasets from Oncomine database. La was also significantly overexpressed in eight HCC cells, compared with normal hepatocytes. According to in vitro experiments, we demonstrated that knockdown of La inhibited HCC cell proliferation and migration. CONCLUSIONS Our results revealed that La expression is elevated both at the RNA and protein levels in HCC. Highly expressed La significantly promotes tumorigenesis of HCC, suggesting that La may be a potential therapeutic target for the treatment of HCC.
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Affiliation(s)
- Jiaqian Pan
- Department of Pharmacy, The Obstetrics and Gynecology Hospital of Fudan University, Shanghai, China
| | - Shuangmei Tong
- Department of Clinical Pharmacy, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lingjun Kong
- Department of Pharmacy, The Obstetrics and Gynecology Hospital of Fudan University, Shanghai, China
| | - Jialei Zhu
- Department of Pharmacy, The Obstetrics and Gynecology Hospital of Fudan University, Shanghai, China
| | - Jing Tang
- Department of Pharmacy, The Obstetrics and Gynecology Hospital of Fudan University, Shanghai, China
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Abstract
RNA-binding proteins are important regulators of RNA metabolism and are of critical importance in all steps of the gene expression cascade. The role of aberrantly expressed RBPs in human disease is an exciting research field and the potential application of RBPs as a therapeutic target or a diagnostic marker represents a fast-growing area of research.Aberrant overexpression of the human RNA-binding protein La has been found in various cancer entities including lung, cervical, head and neck, and chronic myelogenous leukaemia. Cancer-associated La protein supports tumour-promoting processes such as proliferation, mobility, invasiveness and tumour growth. Moreover, the La protein maintains the survival of cancer cells by supporting an anti-apoptotic state that may cause resistance to chemotherapeutic therapy.The human La protein represents a multifunctional post-translationally modified RNA-binding protein with RNA chaperone activity that promotes processing of non-coding precursor RNAs but also stimulates the translation of selective messenger RNAs encoding tumour-promoting and anti-apoptotic factors. In our model, La facilitates the expression of those factors and helps cancer cells to cope with cellular stress. In contrast to oncogenes, able to initiate tumorigenesis, we postulate that the aberrantly elevated expression of the human La protein contributes to the non-oncogenic addiction of cancer cells. In this review, we summarize the current understanding about the implications of the RNA-binding protein La in cancer progression and therapeutic resistance. The concept of exploiting the RBP La as a cancer drug target will be discussed.
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Affiliation(s)
- Gunhild Sommer
- Department for Pediatric Hematology, Oncology and Stem Cell Transplantation, University Hospital Regensburg, Regensburg, Germany
| | - Tilman Heise
- Department for Pediatric Hematology, Oncology and Stem Cell Transplantation, University Hospital Regensburg, Regensburg, Germany
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An in vivo genome-wide CRISPR screen identifies the RNA-binding protein Staufen2 as a key regulator of myeloid leukemia. ACTA ACUST UNITED AC 2020; 1:410-422. [PMID: 34109316 DOI: 10.1038/s43018-020-0054-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Aggressive myeloid leukemias such as blast crisis chronic myeloid leukemia and acute myeloid leukemia remain highly lethal. Here we report a genome-wide in vivo CRISPR screen to identify new dependencies in this disease. Among these, RNA-binding proteins (RBPs) in general, and the double-stranded RBP Staufen2 (Stau2) in particular, emerged as critical regulators of myeloid leukemia. In a newly developed knockout mouse, loss of Stau2 led to a profound decrease in leukemia growth and improved survival in mouse models of the disease. Further, Stau2 was required for growth of primary human blast crisis chronic myeloid leukemia and acute myeloid leukemia. Finally, integrated analysis of CRISPR, eCLIP and RNA-sequencing identified Stau2 as a regulator of chromatin-binding factors, driving global alterations in histone methylation. Collectively, these data show that in vivo CRISPR screening is an effective tool for defining new regulators of myeloid leukemia progression and identify the double-stranded RBP Stau2 as a critical dependency of myeloid malignancies.
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Sommer G, Sendlmeier C, Heise T. Salt-Dependent Modulation of the RNA Chaperone Activity of RNA-Binding Protein La. Methods Mol Biol 2020; 2106:121-136. [PMID: 31889254 DOI: 10.1007/978-1-0716-0231-7_7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
It is well established that the RNA-binding protein La has RNA chaperone activity. Recent work suggests that the La protein has two distinct RNA chaperone domains (RCD-A and RCD-B) assisting structural changes in diverse groups of RNA molecules such as RNA polymerase III transcripts (e.g., pre-tRNA, U6 snRNA), cellular messenger, and viral RNAs. In this protocol we focus on the RNA chaperone domain RCD-B, which is located in the carboxy-terminal domain of La. It has been shown that this RNA chaperone domain assists structural changes in predicted RNA hairpins folded in the 5'-untranslated regions of cyclin D1 and Bcl2 mRNAs. Besides RNA helicases, which are implicated in melting RNA hairpin structures in an ATP-dependent manner, RNA chaperones fulfil a similar function in an ATP-independent manner. Aiming to study the RNA chaperon activity of La, we established a La-dependent molecular beacon-based RNA chaperone assay and systematically tested the various salt conditions. Herein we describe the assay format and design to study the salt dependency of RNA chaperones. This protocol can be easily adapted to test the RNA chaperone activity of other RNA-binding proteins and to optimize assay conditions.
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Affiliation(s)
- Gunhild Sommer
- Department of Pediatric Hematology, Oncology and Stem Cell Transplantation, University Hospital of Regensburg, Regensburg, Germany
| | - Christina Sendlmeier
- Department of Pediatric Hematology, Oncology and Stem Cell Transplantation, University Hospital of Regensburg, Regensburg, Germany
| | - Tilman Heise
- Department of Pediatric Hematology, Oncology and Stem Cell Transplantation, University Hospital of Regensburg, Regensburg, Germany.
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Mechanisms of Disease Progression and Resistance to Tyrosine Kinase Inhibitor Therapy in Chronic Myeloid Leukemia: An Update. Int J Mol Sci 2019; 20:ijms20246141. [PMID: 31817512 PMCID: PMC6940932 DOI: 10.3390/ijms20246141] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 11/29/2019] [Accepted: 12/04/2019] [Indexed: 12/24/2022] Open
Abstract
Chronic myeloid leukemia (CML) is characterized by the presence of the BCR-ABL1 fusion gene, which encodes a constitutive active tyrosine kinase considered to be the pathogenic driver capable of initiating and maintaining the disease. Despite the remarkable efficacy of tyrosine kinase inhibitors (TKIs) targeting BCR-ABL1, some patients may not respond (primary resistance) or may relapse after an initial response (secondary resistance). In a small proportion of cases, development of resistance is accompanied or shortly followed by progression from chronic to blastic phase (BP), characterized by a dismal prognosis. Evolution from CP into BP is a multifactorial and probably multistep phenomenon. Increase in BCR-ABL1 transcript levels is thought to promote the onset of secondary chromosomal or genetic defects, induce differentiation arrest, perturb RNA transcription, editing and translation that together with epigenetic and metabolic changes may ultimately lead to the expansion of highly proliferating, differentiation-arrested malignant cells. A multitude of studies over the past two decades have investigated the mechanisms underlying the closely intertwined phenomena of drug resistance and disease progression. Here, we provide an update on what is currently known on the mechanisms underlying progression and present the latest acquisitions on BCR-ABL1-independent resistance and leukemia stem cell persistence.
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Oncogenic heterogeneous nuclear ribonucleoprotein D-like modulates the growth and imatinib response of human chronic myeloid leukemia CD34 + cells via pre-B-cell leukemia homeobox 1. Oncogene 2019; 39:443-453. [PMID: 31488872 DOI: 10.1038/s41388-019-0998-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 08/09/2019] [Indexed: 12/20/2022]
Abstract
Chronic myeloid leukemia (CML) originates from normal hematopoietic stem cells acquiring BCR-ABL fusion gene, specific BCR-ABL inhibitors (e.g., imatinib mesylate, IM) have greatly improved patient management. However, some patients are still suffering from relapse and drug resistance, which urges better understanding of the growth/survival mechanisms of CML stem/progenitor cells. In the present study, the role and its underlying mechanism of heterogeneous nuclear ribonucleoprotein D-like (HNRPDL) in CML cells were investigated. Firstly, overexpression of HNRPDL promoted the growth of murine BaF3 cells in vitro and induced leukemia in vivo, which was enhanced by co-expression of BCR-ABL. Conversely, HNRPDL silencing inhibited colony-forming cell (CFC) production of CML CD34+ cells and attenuated BCR-ABL induced leukemia. In addition, HNRPDL modulated imatinib response of K562 cells and HNRPDL silencing sensitized CML CD34+ cells to imatinib treatment. Mechanistically, we found the stability of pre-B-cell leukemia homeobox 1 (PBX1) mRNA was sustained by HNRPDL through its binding to a specific motif (ACUAGC) in 3'-untranslated region (3'-UTR) of PBX1. The expression of PBX1 was significantly higher in CML CD34+ cells than that in control cells and PBX silencing inhibited the growth of CML cells and sensitized them to imatinib treatment. In contrast, overexpression of PBX1 elevated the CFC production of normal hematopoietic CD34+ cells and "rescued" HNRPDL silencing induced growth inhibition and imatinib sensitization. Taken together, our data have demonstrated that HNRPDL transforms hematopoietic cells and a novel HNRPDL/PBX1 axis plays an important role in human CML CD34+ cells.
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Barbosa K, Li S, Adams PD, Deshpande AJ. The role of TP53 in acute myeloid leukemia: Challenges and opportunities. Genes Chromosomes Cancer 2019; 58:875-888. [DOI: 10.1002/gcc.22796] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 08/02/2019] [Accepted: 08/05/2019] [Indexed: 12/16/2022] Open
Affiliation(s)
- Karina Barbosa
- Tumor Initiation and Maintenance Program Sanford Burnham Prebys Medical Discovery Institute La Jolla California
| | - Sha Li
- Tumor Initiation and Maintenance Program Sanford Burnham Prebys Medical Discovery Institute La Jolla California
| | - Peter D. Adams
- Tumor Initiation and Maintenance Program Sanford Burnham Prebys Medical Discovery Institute La Jolla California
| | - Aniruddha J. Deshpande
- Tumor Initiation and Maintenance Program Sanford Burnham Prebys Medical Discovery Institute La Jolla California
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Temoche-Diaz MM, Shurtleff MJ, Nottingham RM, Yao J, Fadadu RP, Lambowitz AM, Schekman R. Distinct mechanisms of microRNA sorting into cancer cell-derived extracellular vesicle subtypes. eLife 2019; 8:e47544. [PMID: 31436530 PMCID: PMC6728143 DOI: 10.7554/elife.47544] [Citation(s) in RCA: 145] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 08/21/2019] [Indexed: 12/11/2022] Open
Abstract
Extracellular vesicles (EVs) encompass a variety of vesicles secreted into the extracellular space. EVs have been implicated in promoting tumor metastasis, but the molecular composition of tumor-derived EV sub-types and the mechanisms by which molecules are sorted into EVs remain mostly unknown. We report the separation of two small EV sub-populations from a metastatic breast cancer cell line, with biochemical features consistent with different sub-cellular origins. These EV sub-types use different mechanisms of miRNA sorting (selective and non-selective), suggesting that sorting occurs via fundamentally distinct processes, possibly dependent on EV origin. Using biochemical and genetic tools, we identified the Lupus La protein as mediating sorting of selectively packaged miRNAs. We found that two motifs embedded in miR-122 are responsible for high-affinity binding to Lupus La and sorting into vesicles formed in a cell-free reaction. Thus, tumor cells can simultaneously deploy multiple EV species using distinct sorting mechanisms that may enable diverse functions in normal and cancer biology.
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Affiliation(s)
- Morayma M Temoche-Diaz
- Department of Plant and Microbial BiologyUniversity of California, BerkeleyBerkeleyUnited States
| | - Matthew J Shurtleff
- Department of Plant and Microbial BiologyUniversity of California, BerkeleyBerkeleyUnited States
- Department of Molecular and Cellular BiologyHoward Hughes Medical Institute, University of California, BerkeleyBerkeleyUnited States
| | - Ryan M Nottingham
- Department of Molecular Biosciences, Institute for Cellular and Molecular BiologyUniversity of TexasAustinUnited States
| | - Jun Yao
- Department of Molecular Biosciences, Institute for Cellular and Molecular BiologyUniversity of TexasAustinUnited States
| | - Raj P Fadadu
- Department of Molecular and Cellular BiologyHoward Hughes Medical Institute, University of California, BerkeleyBerkeleyUnited States
| | - Alan M Lambowitz
- Department of Molecular Biosciences, Institute for Cellular and Molecular BiologyUniversity of TexasAustinUnited States
| | - Randy Schekman
- Department of Molecular and Cellular BiologyHoward Hughes Medical Institute, University of California, BerkeleyBerkeleyUnited States
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Vinayak J, Marrella SA, Hussain RH, Rozenfeld L, Solomon K, Bayfield MA. Human La binds mRNAs through contacts to the poly(A) tail. Nucleic Acids Res 2019; 46:4228-4240. [PMID: 29447394 PMCID: PMC5934636 DOI: 10.1093/nar/gky090] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 01/31/2018] [Indexed: 12/31/2022] Open
Abstract
In addition to a role in the processing of nascent RNA polymerase III transcripts, La proteins are also associated with promoting cap-independent translation from the internal ribosome entry sites of numerous cellular and viral coding RNAs. La binding to RNA polymerase III transcripts via their common UUU-3’OH motif is well characterized, but the mechanism of La binding to coding RNAs is poorly understood. Using electromobility shift assays and cross-linking immunoprecipitation, we show that in addition to a sequence specific UUU-3’OH binding mode, human La exhibits a sequence specific and length dependent poly(A) binding mode. We demonstrate that this poly(A) binding mode uses the canonical nucleic acid interaction winged helix face of the eponymous La motif, previously shown to be vacant during uridylate binding. We also show that cytoplasmic, but not nuclear La, engages poly(A) RNA in human cells, that La entry into polysomes utilizes the poly(A) binding mode, and that La promotion of translation from the cyclin D1 internal ribosome entry site occurs in competition with cytoplasmic poly(A) binding protein (PABP). Our data are consistent with human La functioning in translation through contacts to the poly(A) tail.
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Affiliation(s)
- Jyotsna Vinayak
- Department of Biology, York University, 4700 Keele St., Life Science Building #327E, Toronto, ON M3J 1P3, Canada
| | - Stefano A Marrella
- Department of Biology, York University, 4700 Keele St., Life Science Building #327E, Toronto, ON M3J 1P3, Canada
| | - Rawaa H Hussain
- Department of Biology, York University, 4700 Keele St., Life Science Building #327E, Toronto, ON M3J 1P3, Canada
| | - Leonid Rozenfeld
- Department of Biology, York University, 4700 Keele St., Life Science Building #327E, Toronto, ON M3J 1P3, Canada
| | - Karine Solomon
- Department of Biology, York University, 4700 Keele St., Life Science Building #327E, Toronto, ON M3J 1P3, Canada
| | - Mark A Bayfield
- Department of Biology, York University, 4700 Keele St., Life Science Building #327E, Toronto, ON M3J 1P3, Canada
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Mohibi S, Chen X, Zhang J. Cancer the'RBP'eutics-RNA-binding proteins as therapeutic targets for cancer. Pharmacol Ther 2019; 203:107390. [PMID: 31302171 DOI: 10.1016/j.pharmthera.2019.07.001] [Citation(s) in RCA: 121] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 07/02/2019] [Indexed: 12/11/2022]
Abstract
RNA-binding proteins (RBPs) play a critical role in the regulation of various RNA processes, including splicing, cleavage and polyadenylation, transport, translation and degradation of coding RNAs, non-coding RNAs and microRNAs. Recent studies indicate that RBPs not only play an instrumental role in normal cellular processes but have also emerged as major players in the development and spread of cancer. Herein, we review the current knowledge about RNA binding proteins and their role in tumorigenesis as well as the potential to target RBPs for cancer therapeutics.
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Affiliation(s)
- Shakur Mohibi
- Comparative Oncology Laboratory, Schools of Veterinary Medicine and Medicine, University of California at Davis, United States
| | - Xinbin Chen
- Comparative Oncology Laboratory, Schools of Veterinary Medicine and Medicine, University of California at Davis, United States
| | - Jin Zhang
- Comparative Oncology Laboratory, Schools of Veterinary Medicine and Medicine, University of California at Davis, United States.
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28
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Jiang Q, Isquith J, Zipeto MA, Diep RH, Pham J, Delos Santos N, Reynoso E, Chau J, Leu H, Lazzari E, Melese E, Ma W, Fang R, Minden M, Morris S, Ren B, Pineda G, Holm F, Jamieson C. Hyper-Editing of Cell-Cycle Regulatory and Tumor Suppressor RNA Promotes Malignant Progenitor Propagation. Cancer Cell 2019; 35:81-94.e7. [PMID: 30612940 PMCID: PMC6333511 DOI: 10.1016/j.ccell.2018.11.017] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 10/20/2018] [Accepted: 11/26/2018] [Indexed: 12/26/2022]
Abstract
Adenosine deaminase associated with RNA1 (ADAR1) deregulation contributes to therapeutic resistance in many malignancies. Here we show that ADAR1-induced hyper-editing in normal human hematopoietic progenitors impairs miR-26a maturation, which represses CDKN1A expression indirectly via EZH2, thereby accelerating cell-cycle transit. However, in blast crisis chronic myeloid leukemia progenitors, loss of EZH2 expression and increased CDKN1A oppose cell-cycle transit. Moreover, A-to-I editing of both the MDM2 regulatory microRNA and its binding site within the 3' UTR region stabilizes MDM2 transcripts, thereby enhancing blast crisis progenitor propagation. These data reveal a dual mechanism governing malignant transformation of progenitors that is predicated on hyper-editing of cell-cycle-regulatory miRNAs and the 3' UTR binding site of tumor suppressor miRNAs.
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Affiliation(s)
- Qingfei Jiang
- Division of Regenerative Medicine, Department of Medicine, Moores Cancer Center and Sanford Consortium for Regenerative Medicine, University of California, San Diego, La Jolla, CA, USA; Sanford Consortium for Regenerative Medicine, La Jolla, CA 92037, USA.
| | - Jane Isquith
- Division of Regenerative Medicine, Department of Medicine, Moores Cancer Center and Sanford Consortium for Regenerative Medicine, University of California, San Diego, La Jolla, CA, USA; Sanford Consortium for Regenerative Medicine, La Jolla, CA 92037, USA
| | - Maria Anna Zipeto
- Division of Regenerative Medicine, Department of Medicine, Moores Cancer Center and Sanford Consortium for Regenerative Medicine, University of California, San Diego, La Jolla, CA, USA; Sanford Consortium for Regenerative Medicine, La Jolla, CA 92037, USA
| | - Raymond H Diep
- Division of Regenerative Medicine, Department of Medicine, Moores Cancer Center and Sanford Consortium for Regenerative Medicine, University of California, San Diego, La Jolla, CA, USA; Sanford Consortium for Regenerative Medicine, La Jolla, CA 92037, USA
| | - Jessica Pham
- Division of Regenerative Medicine, Department of Medicine, Moores Cancer Center and Sanford Consortium for Regenerative Medicine, University of California, San Diego, La Jolla, CA, USA; Sanford Consortium for Regenerative Medicine, La Jolla, CA 92037, USA
| | - Nathan Delos Santos
- Division of Regenerative Medicine, Department of Medicine, Moores Cancer Center and Sanford Consortium for Regenerative Medicine, University of California, San Diego, La Jolla, CA, USA; Sanford Consortium for Regenerative Medicine, La Jolla, CA 92037, USA
| | - Eduardo Reynoso
- Division of Regenerative Medicine, Department of Medicine, Moores Cancer Center and Sanford Consortium for Regenerative Medicine, University of California, San Diego, La Jolla, CA, USA; Sanford Consortium for Regenerative Medicine, La Jolla, CA 92037, USA
| | - Julisia Chau
- Division of Regenerative Medicine, Department of Medicine, Moores Cancer Center and Sanford Consortium for Regenerative Medicine, University of California, San Diego, La Jolla, CA, USA; Sanford Consortium for Regenerative Medicine, La Jolla, CA 92037, USA
| | - Heather Leu
- Division of Regenerative Medicine, Department of Medicine, Moores Cancer Center and Sanford Consortium for Regenerative Medicine, University of California, San Diego, La Jolla, CA, USA; Sanford Consortium for Regenerative Medicine, La Jolla, CA 92037, USA
| | - Elisa Lazzari
- Division of Regenerative Medicine, Department of Medicine, Moores Cancer Center and Sanford Consortium for Regenerative Medicine, University of California, San Diego, La Jolla, CA, USA; Sanford Consortium for Regenerative Medicine, La Jolla, CA 92037, USA
| | - Etienne Melese
- Sanford Consortium for Regenerative Medicine, La Jolla, CA 92037, USA; Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Wenxue Ma
- Division of Regenerative Medicine, Department of Medicine, Moores Cancer Center and Sanford Consortium for Regenerative Medicine, University of California, San Diego, La Jolla, CA, USA; Sanford Consortium for Regenerative Medicine, La Jolla, CA 92037, USA
| | - Rongxin Fang
- Ludwig Institute for Cancer Research, La Jolla, CA 92093, USA; Bioinformatics and Systems Biology Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Mark Minden
- Princess Margaret Hospital, Toronto, ON M5T 2M9, Canada
| | - Sheldon Morris
- Division of Regenerative Medicine, Department of Medicine, Moores Cancer Center and Sanford Consortium for Regenerative Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Bing Ren
- Ludwig Institute for Cancer Research, La Jolla, CA 92093, USA; Center for Epigenomics, Department of Cellular and Molecular Medicine, University of California, San Diego, School of Medicine, La Jolla, CA, USA; Department of Cellular and Molecular Medicine, Institute of Genomic Medicine, and Moores Cancer Center, University of California at San Diego, La Jolla, CA 92093, USA
| | - Gabriel Pineda
- Division of Regenerative Medicine, Department of Medicine, Moores Cancer Center and Sanford Consortium for Regenerative Medicine, University of California, San Diego, La Jolla, CA, USA; Sanford Consortium for Regenerative Medicine, La Jolla, CA 92037, USA; Department of Health Sciences, School of Health and Human Services, National University, San Diego, CA, USA
| | - Frida Holm
- Division of Regenerative Medicine, Department of Medicine, Moores Cancer Center and Sanford Consortium for Regenerative Medicine, University of California, San Diego, La Jolla, CA, USA; Sanford Consortium for Regenerative Medicine, La Jolla, CA 92037, USA
| | - Catriona Jamieson
- Division of Regenerative Medicine, Department of Medicine, Moores Cancer Center and Sanford Consortium for Regenerative Medicine, University of California, San Diego, La Jolla, CA, USA; Sanford Consortium for Regenerative Medicine, La Jolla, CA 92037, USA.
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Marrella SA, Brown KA, Mansouri-Noori F, Porat J, Wilson DJ, Bayfield MA. An interdomain bridge influences RNA binding of the human La protein. J Biol Chem 2018; 294:1529-1540. [PMID: 30530494 DOI: 10.1074/jbc.ra118.003995] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 11/20/2018] [Indexed: 12/15/2022] Open
Abstract
La proteins are RNA chaperones that perform various functions depending on distinct RNA-binding modes and their subcellular localization. In the nucleus, they help process UUU-3'OH-tailed nascent RNA polymerase III transcripts, such as pre-tRNAs, whereas in the cytoplasm they contribute to translation of poly(A)-tailed mRNAs. La accumulation in the nucleus and cytoplasm is controlled by several trafficking elements, including a canonical nuclear localization signal in the extreme C terminus and a nuclear retention element (NRE) in the RNA recognition motif 2 (RRM2) domain. Previous findings indicate that cytoplasmic export of La due to mutation of the NRE can be suppressed by mutations in RRM1, but the mechanism by which the RRM1 and RRM2 domains functionally cooperate is poorly understood. In this work, we use electromobility shift assays (EMSA) to show that mutations in the NRE and RRM1 affect binding of human La to pre-tRNAs but not UUU-3'OH or poly(A) sequences, and we present compensatory mutagenesis data supporting a direct interaction between the RRM1 and RRM2 domains. Moreover, we use collision-induced unfolding and time-resolved hydrogen-deuterium exchange MS analyses to study the conformational dynamics that occur when this interaction is intact or disrupted. Our results suggest that the intracellular distribution of La may be linked to its RNA-binding modes and provide the first evidence for a direct protein-protein interdomain interaction in La proteins.
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Affiliation(s)
- Stefano A Marrella
- Department of Biology, York University, Toronto, Ontario M3J 1P3, Canada; Centres for Research in Biomolecular Interactions, York University, Toronto, Ontario M3J 1P3, Canada
| | - Kerene A Brown
- Centres for Research in Biomolecular Interactions, York University, Toronto, Ontario M3J 1P3, Canada; Department of Chemistry, York University, Toronto, Ontario M3J 1P3, Canada; Research in Mass Spectrometry, York University, Toronto, Ontario M3J 1P3, Canada
| | - Farnaz Mansouri-Noori
- Department of Biology, York University, Toronto, Ontario M3J 1P3, Canada; Centres for Research in Biomolecular Interactions, York University, Toronto, Ontario M3J 1P3, Canada
| | - Jennifer Porat
- Department of Biology, York University, Toronto, Ontario M3J 1P3, Canada; Centres for Research in Biomolecular Interactions, York University, Toronto, Ontario M3J 1P3, Canada
| | - Derek J Wilson
- Centres for Research in Biomolecular Interactions, York University, Toronto, Ontario M3J 1P3, Canada; Department of Chemistry, York University, Toronto, Ontario M3J 1P3, Canada; Research in Mass Spectrometry, York University, Toronto, Ontario M3J 1P3, Canada.
| | - Mark A Bayfield
- Department of Biology, York University, Toronto, Ontario M3J 1P3, Canada; Centres for Research in Biomolecular Interactions, York University, Toronto, Ontario M3J 1P3, Canada.
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30
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Staudacher AH, Li Y, Liapis V, Hou JJC, Chin D, Dolezal O, Adams TE, van Berkel PH, Brown MP. APOMAB Antibody–Drug Conjugates Targeting Dead Tumor Cells are Effective In Vivo. Mol Cancer Ther 2018; 18:335-345. [DOI: 10.1158/1535-7163.mct-18-0842] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 10/05/2018] [Accepted: 11/05/2018] [Indexed: 11/16/2022]
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31
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Zeng C, Liu S, Lu S, Yu X, Lai J, Wu Y, Chen S, Wang L, Yu Z, Luo G, Li Y. The c-Myc-regulated lncRNA NEAT1 and paraspeckles modulate imatinib-induced apoptosis in CML cells. Mol Cancer 2018; 17:130. [PMID: 30153828 PMCID: PMC6114538 DOI: 10.1186/s12943-018-0884-z] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 08/22/2018] [Indexed: 12/25/2022] Open
Abstract
Chronic myeloid leukemia (CML) is a clonal disease characterized by the presence of the constitutively active tyrosine kinase BCR-ABL oncoprotein. Although BCR-ABL is crucially important for pathogenesis and treatment response, it is thought that some additional factors might be involved in the regulation of these processes. Aberrant expression of long noncoding RNAs (lncRNAs) has recently been identified to be involved in various diseases including cancer, suggesting that lncRNAs may play a role in BCR-ABL-mediated CML. In this study, we found that nuclear-enriched abundant transcript 1 (NEAT1), a lncRNA essential for the formation of nuclear body paraspeckles, is significantly repressed in primary CML cells. NEAT1 expression could be restored by inhibiting BCR-ABL expression or its kinase activity in K562 cells. We also demonstrated that NEAT1 is regulated by c-Myc. Knockdown of NEAT1 could promote imatinib (IM)-induced apoptosis, and we demonstrated that the NEAT1-binding paraspeckle protein splicing factor proline/glutamine-rich (SFPQ) is required for NEAT1-mediated apoptosis in K562 cells. RNA-seq analysis revealed that SFPQ regulates cell growth and death pathway-related genes, confirming its function in IM-induced apoptosis. Collectively, these results assign a biological function to the NEAT1 lncRNA in CML apoptosis and may lead to fuller understanding of the molecular events leading to CML.
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Affiliation(s)
- Chengwu Zeng
- Key Laboratory for Regenerative Medicine of Ministry of Education, Institute of Hematology, Jinan University, Guangzhou, 510632, China. .,Department of Hematology, First Affiliated Hospital, Jinan University, Guangzhou, 510632, China.
| | - Sichu Liu
- Key Laboratory for Regenerative Medicine of Ministry of Education, Institute of Hematology, Jinan University, Guangzhou, 510632, China
| | - Shuai Lu
- Key Laboratory for Regenerative Medicine of Ministry of Education, Institute of Hematology, Jinan University, Guangzhou, 510632, China
| | - Xibao Yu
- Key Laboratory for Regenerative Medicine of Ministry of Education, Institute of Hematology, Jinan University, Guangzhou, 510632, China
| | - Jing Lai
- Department of Hematology, First Affiliated Hospital, Jinan University, Guangzhou, 510632, China
| | - Yifan Wu
- Key Laboratory for Regenerative Medicine of Ministry of Education, Institute of Hematology, Jinan University, Guangzhou, 510632, China
| | - Shaohua Chen
- Key Laboratory for Regenerative Medicine of Ministry of Education, Institute of Hematology, Jinan University, Guangzhou, 510632, China
| | - Liang Wang
- Department of Oncology, First Hospital Affiliated, Jinan University, Guangzhou, 510632, China
| | - Zhi Yu
- Department of Hematology, First Affiliated Hospital, Jinan University, Guangzhou, 510632, China
| | - Gengxin Luo
- Department of Hematology, First Affiliated Hospital, Jinan University, Guangzhou, 510632, China
| | - Yangqiu Li
- Key Laboratory for Regenerative Medicine of Ministry of Education, Institute of Hematology, Jinan University, Guangzhou, 510632, China. .,Department of Hematology, First Affiliated Hospital, Jinan University, Guangzhou, 510632, China.
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32
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de Rooij LPMH, Chan DCH, Keyvani Chahi A, Hope KJ. Post-transcriptional regulation in hematopoiesis: RNA binding proteins take control 1. Biochem Cell Biol 2018; 97:10-20. [PMID: 29898370 DOI: 10.1139/bcb-2017-0310] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Normal hematopoiesis is sustained through a carefully orchestrated balance between hematopoietic stem cell (HSC) self-renewal and differentiation. The functional importance of this axis is underscored by the severity of disease phenotypes initiated by abnormal HSC function, including myelodysplastic syndromes and hematopoietic malignancies. Major advances in the understanding of transcriptional regulation of primitive hematopoietic cells have been achieved; however, the post-transcriptional regulatory layer that may impinge on their behavior remains underexplored by comparison. Key players at this level include RNA-binding proteins (RBPs), which execute precise and highly coordinated control of gene expression through modulation of RNA properties that include its splicing, polyadenylation, localization, degradation, or translation. With the recent identification of RBPs having essential roles in regulating proliferation and cell fate decisions in other systems, there has been an increasing appreciation of the importance of post-transcriptional control at the stem cell level. Here we discuss our current understanding of RBP-driven post-transcriptional regulation in HSCs, its implications for normal, perturbed, and malignant hematopoiesis, and the most recent technological innovations aimed at RBP-RNA network characterization at the systems level. Emerging evidence highlights RBP-driven control as an underappreciated feature of primitive hematopoiesis, the greater understanding of which has important clinical implications.
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Affiliation(s)
- Laura P M H de Rooij
- Department of Biochemistry and Biomedical Sciences, Stem Cell and Cancer Research Institute, McMaster University, Hamilton, ON L8S 4K1, Canada.,Department of Biochemistry and Biomedical Sciences, Stem Cell and Cancer Research Institute, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Derek C H Chan
- Department of Biochemistry and Biomedical Sciences, Stem Cell and Cancer Research Institute, McMaster University, Hamilton, ON L8S 4K1, Canada.,Department of Biochemistry and Biomedical Sciences, Stem Cell and Cancer Research Institute, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Ava Keyvani Chahi
- Department of Biochemistry and Biomedical Sciences, Stem Cell and Cancer Research Institute, McMaster University, Hamilton, ON L8S 4K1, Canada.,Department of Biochemistry and Biomedical Sciences, Stem Cell and Cancer Research Institute, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Kristin J Hope
- Department of Biochemistry and Biomedical Sciences, Stem Cell and Cancer Research Institute, McMaster University, Hamilton, ON L8S 4K1, Canada.,Department of Biochemistry and Biomedical Sciences, Stem Cell and Cancer Research Institute, McMaster University, Hamilton, ON L8S 4K1, Canada
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Lobello C, Bikos V, Janikova A, Pospisilova S. The Role of Oncogenic Tyrosine Kinase NPM-ALK in Genomic Instability. Cancers (Basel) 2018; 10:cancers10030064. [PMID: 29510549 PMCID: PMC5876639 DOI: 10.3390/cancers10030064] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 02/20/2018] [Accepted: 02/27/2018] [Indexed: 12/16/2022] Open
Abstract
Genomic stability is crucial for cell life and transmitting genetic material is one of the primary tasks of the cell. The cell needs to be able to recognize any possible error and quickly repair it, and thus, cells have developed several mechanisms to detect DNA damage and promote repair during evolution. The DNA damage response (DDR) and DNA repair pathways ensure the control of possible errors that could impair the duplication of genetic information and introduce variants in the DNA. Endogenous and exogenous factors compromise genomic stability and cause dysregulation in the DDR and DNA repair pathways. Cancer cells often impair these mechanisms to overcome cellular barriers (cellular senescence and/or apoptosis), leading to malignancy. NPM (nucleophosmin)-ALK (anaplastic lymphoma kinase) is an oncogenic tyrosine kinase that is involved in the development of anaplastic large cell lymphoma (ALCL). NPM-ALK is known to be involved in the activation of proliferative and anti-apoptotic signaling pathways. New evidence reveals that NPM-ALK translocation also impairs the ability of cells to maintain the genomic stability through both DDR and DNA repair pathways. This review aims to highlight the role of the oncogenic tyrosine kinase NPM-ALK in the cell, and pointing to new possible therapeutic strategies.
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Affiliation(s)
- Cosimo Lobello
- Central European Institute of Technology (CEITEC), Masaryk University, Kamenice 5, 62500 Brno, Czech Republic.
| | - Vasilis Bikos
- Central European Institute of Technology (CEITEC), Masaryk University, Kamenice 5, 62500 Brno, Czech Republic.
| | - Andrea Janikova
- Department of Internal Medicine-Hematology and Oncology, University Hospital Brno, 62500 Brno, Czech Republic.
| | - Sarka Pospisilova
- Central European Institute of Technology (CEITEC), Masaryk University, Kamenice 5, 62500 Brno, Czech Republic.
- Department of Internal Medicine-Hematology and Oncology, University Hospital Brno, 62500 Brno, Czech Republic.
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34
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You L, Liu H, Huang J, Xie W, Wei J, Ye X, Qian W. The novel anticancer agent JNJ-26854165 is active in chronic myeloid leukemic cells with unmutated BCR/ABL and T315I mutant BCR/ABL through promoting proteosomal degradation of BCR/ABL proteins. Oncotarget 2018; 8:7777-7790. [PMID: 27999193 PMCID: PMC5352360 DOI: 10.18632/oncotarget.13951] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2016] [Accepted: 12/05/2016] [Indexed: 12/21/2022] Open
Abstract
Chronic myeloid leukemia (CML) is a clonal malignant disease caused by the expression of BCR/ABL. MDM2 (human homolog of the murine double minute-2) inhibitors such as Nutlin-3 have been shown to induce apoptosis in a p53-dependent manner in CML cells and sensitize cells to Imatinib. Here, we demonstrate that JNJ-26854165, an inhibitor of MDM2, inhibits proliferation and triggers cell death in a p53-independent manner in various BCR/ABL-expressing cells, which include primary leukemic cells from patients with CML blast crisis and cells expressing the Imatinib-resistant T315I BCR/ABL mutant. The response to JNJ-26854165 is associated with the downregulation of BCR/ABL dependently of proteosome activation. Moreover, in all tested CML cells, with the exception of T315I mutation cells, combining JNJ-26854165 and tyrosine kinase inhibitor (TKI) Imatinib or PD180970 leads to a synergistic effect. In conclusion, our results suggest that JNJ-26854165, used either alone or in combination with TKIs, represents a promising novel targeted approach to overcome TKI resistance and improve patient outcome in CML.
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Affiliation(s)
- Liangshun You
- Institute of Hematology, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310003, P.R. China
| | - Hui Liu
- Institute of Hematology, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310003, P.R. China
| | - Jian Huang
- Department of Hematology, The Fourth Affiliated Hospital, College of Medicine, Zhejiang University, Yiwu 322000, P.R. China
| | - Wanzhuo Xie
- Institute of Hematology, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310003, P.R. China
| | - Jueying Wei
- Institute of Hematology, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310003, P.R. China
| | - Xiujin Ye
- Institute of Hematology, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310003, P.R. China
| | - Wenbin Qian
- Institute of Hematology, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310003, P.R. China
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35
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The La protein counteracts cisplatin-induced cell death by stimulating protein synthesis of anti-apoptotic factor Bcl2. Oncotarget 2018; 7:29664-76. [PMID: 27105491 PMCID: PMC5045424 DOI: 10.18632/oncotarget.8819] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 03/28/2016] [Indexed: 02/06/2023] Open
Abstract
Up-regulation of anti-apoptotic factors is a critical mechanism of cancer cell resistance and often counteracts the success of chemotherapeutic treatment. Herein, we identified the cancer-associated RNA-binding protein La as novel factor contributing to cisplatin resistance. Our data demonstrate that depletion of the RNA-binding protein La in head and neck squamous cell carcinoma cells (HNSCC) increases the sensitivity toward cisplatin-induced cell death paralleled by reduced expression of the anti-apoptotic factor Bcl2. Furthermore, it is shown that transient expression of Bcl2 in La-depleted cells protects against cisplatin-induced cell death. By dissecting the underlying mechanism we report herein, that the La protein is required for Bcl2 protein synthesis in cisplatin-treated cells. The RNA chaperone La binds in close proximity to the authentic translation start site and unwinds a secondary structure embedding the authentic AUG. Altogether, our data support a novel model, whereby cancer-associated La protein contributes to cisplatin resistance by stimulating the translation of anti-apoptotic factor Bcl2 in HNSCC cells.
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36
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Hong S. RNA Binding Protein as an Emerging Therapeutic Target for Cancer Prevention and Treatment. J Cancer Prev 2017; 22:203-210. [PMID: 29302577 PMCID: PMC5751837 DOI: 10.15430/jcp.2017.22.4.203] [Citation(s) in RCA: 101] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 11/17/2017] [Accepted: 11/21/2017] [Indexed: 12/13/2022] Open
Abstract
After transcription, RNAs are always associated with RNA binding proteins (RBPs) to perform biological activities. RBPs can interact with target RNAs in sequence- and structure-dependent manner through their unique RNA binding domains. In development and progression of carcinogenesis, RBPs are aberrantly dysregulated in many human cancers with various mechanisms, such as genetic alteration, epigenetic change, noncoding RNA-mediated regulation, and post-translational modifications. Upon deregulation in cancers, RBPs influence every step in the development and progression of cancer, including sustained cell proliferation, evasion of apoptosis, avoiding immune surveillance, inducing angiogenesis, and activating metastasis. To develop therapeutic strategies targeting RBPs, RNA interference-based oligonucleotides or small molecule inhibitors have been screened based on reduced RBP-RNA interaction and changed level of target RNAs. Identification of binding RNAs with high-throughput techniques and integral analysis of multiple datasets will help us develop new therapeutic drugs or prognostic biomarkers for human cancers.
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Affiliation(s)
- Suntaek Hong
- Department of Biochemistry, College of Medicine, Gachon University, Incheon, Korea
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37
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SUMO Modification of the RNA-Binding Protein La Regulates Cell Proliferation and STAT3 Protein Stability. Mol Cell Biol 2017; 38:MCB.00129-17. [PMID: 29084811 DOI: 10.1128/mcb.00129-17] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 10/19/2017] [Indexed: 01/06/2023] Open
Abstract
The cancer-associated RNA-binding protein La is posttranslationally modified by phosphorylation and sumoylation. Sumoylation of La regulates not only the trafficking of La in neuronal axons but also its association with specific mRNAs. Depletion of La in various types of cancer cell lines impairs cell proliferation; however, the molecular mechanism whereby La supports cell proliferation is not clearly understood. In this study, we address the question of whether sumoylation of La contributes to cell proliferation of HEK293 cells. We show that HEK293 cells stably expressing green fluorescent protein (GFP)-tagged wild-type La (GFP-LaWT) grow faster than cells expressing a sumoylation-deficient mutant La (GFP-LaSD), suggesting a proproliferative function of La in HEK293 cells. Further, we found that STAT3 protein levels were reduced in GFP-LaSD cells due to an increase in STAT3 ubiquitination and that overexpression of STAT3 partially restored cell proliferation. Finally, we present RNA sequencing data from RNA immunoprecipitations (RIPs) and report that mRNAs associated with the cell cycle and ubiquitination are preferentially bound by GFP-LaWT and are less enriched in GFP-LaSD RIPs. Taken together, results of our study support a novel mechanism whereby sumoylation of La promotes cell proliferation by averting ubiquitination-mediated degradation of the STAT3 protein.
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Maraia RJ, Mattijssen S, Cruz-Gallardo I, Conte MR. The La and related RNA-binding proteins (LARPs): structures, functions, and evolving perspectives. WILEY INTERDISCIPLINARY REVIEWS. RNA 2017; 8:10.1002/wrna.1430. [PMID: 28782243 PMCID: PMC5647580 DOI: 10.1002/wrna.1430] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 05/12/2017] [Accepted: 05/15/2017] [Indexed: 01/02/2023]
Abstract
La was first identified as a polypeptide component of ribonucleic protein complexes targeted by antibodies in autoimmune patients and is now known to be a eukaryote cell-ubiquitous protein. Structure and function studies have shown that La binds to a common terminal motif, UUU-3'-OH, of nascent RNA polymerase III (RNAP III) transcripts and protects them from exonucleolytic decay. For precursor-tRNAs, the most diverse and abundant of these transcripts, La also functions as an RNA chaperone that helps to prevent their misfolding. Related to this, we review evidence that suggests that La and its link to RNAP III were significant in the great expansions of the tRNAomes that occurred in eukaryotes. Four families of La-related proteins (LARPs) emerged during eukaryotic evolution with specialized functions. We provide an overview of the high-resolution structural biology of La and LARPs. LARP7 family members most closely resemble La but function with a single RNAP III nuclear transcript, 7SK, or telomerase RNA. A cytoplasmic isoform of La protein as well as LARPs 6, 4, and 1 function in mRNA metabolism and translation in distinct but similar ways, sometimes with the poly(A)-binding protein, and in some cases by direct binding to poly(A)-RNA. New structures of LARP domains, some complexed with RNA, provide novel insights into the functional versatility of these proteins. We also consider LARPs in relation to ancestral La protein and potential retention of links to specific RNA-related pathways. One such link may be tRNA surveillance and codon usage by LARP-associated mRNAs. WIREs RNA 2017, 8:e1430. doi: 10.1002/wrna.1430 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Richard J. Maraia
- Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD USA
- Commissioned Corps, U.S. Public Health Service, Rockville, MD USA
| | - Sandy Mattijssen
- Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD USA
| | - Isabel Cruz-Gallardo
- Randall Division of Cell and Molecular Biophysics, King's College London, Guy's Campus, London, UK
| | - Maria R. Conte
- Randall Division of Cell and Molecular Biophysics, King's College London, Guy's Campus, London, UK
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Pan J, Tong S, Tang J. Alteration of microRNA profiles by a novel inhibitor of human La protein in HBV-transformed human hepatoma cells. J Med Virol 2017; 90:255-262. [PMID: 28885699 PMCID: PMC5763324 DOI: 10.1002/jmv.24941] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2017] [Accepted: 08/23/2017] [Indexed: 12/22/2022]
Abstract
A pyrazolopyridine HBSC11 was previously identified as a novel inhibitor of human La protein with anti‐hepatitis B virus (HBV) activity. However, the underlying mechanism(s) of HBV inhibition by HBSC11 remains unclear. This study aimed to examine the regulation of microRNA (miRNA) by HBSC11 in HBV‐transformed human hepatoma HepG2.2.15 cells using microarray and quantitative real‐time PCR. Target genes of the differentially expressed miRNAs were predicted and subjected to bioinformatics analysis. Results showed that HBSC11 significantly upregulated the expression of miR‐3912‐5p, miR‐6793‐5p, and miR‐7159‐5p in HepG2.2.15 cells. Target genes of the three miRNAs were mainly involved in the regulation of nucleic acid‐templated transcription, negative regulation of gene expression, nucleic acid binding transcription factor activity and regulation of phosphorylation. In addition, target genes were enriched in certain regulatory pathways related to HBV infection and HBV‐associated disease progression, such as the transforming growth factor (TGF)‐β, Wnt, and p53 signaling. Our study demonstrates the involvement of miR‐3912‐5p, miR‐6793‐5p, and miR‐7159‐5p and the potential modulation of specific pathways (TGF‐β, Wnt, and p53 signaling) in HBSC11‐mediated inhibition of HBV replication. This study provides insight into the molecular mechanism of the action of HBSC11 against HBV infection and will support the development of antiviral drugs targeting La protein.
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Affiliation(s)
- Jiaqian Pan
- Department of Clinical Pharmacy, Shanghai General Hospital of Nanjing Medical University, Shanghai, China.,Department of Clinical Pharmacy, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Shuangmei Tong
- Department of Clinical Pharmacy, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jing Tang
- Department of Clinical Pharmacy, Shanghai General Hospital of Nanjing Medical University, Shanghai, China.,Department of Clinical Pharmacy, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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40
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Prokocimer M, Molchadsky A, Rotter V. Dysfunctional diversity of p53 proteins in adult acute myeloid leukemia: projections on diagnostic workup and therapy. Blood 2017; 130:699-712. [PMID: 28607134 PMCID: PMC5659817 DOI: 10.1182/blood-2017-02-763086] [Citation(s) in RCA: 114] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2017] [Accepted: 06/06/2017] [Indexed: 12/13/2022] Open
Abstract
The heterogeneous nature of acute myeloid leukemia (AML) and its poor prognosis necessitate therapeutic improvement. Current advances in AML research yield important insights regarding AML genetic, epigenetic, evolutional, and clinical diversity, all in which dysfunctional p53 plays a key role. As p53 is central to hematopoietic stem cell functions, its aberrations affect AML evolution, biology, and therapy response and usually predict poor prognosis. While in human solid tumors TP53 is mutated in more than half of cases, TP53 mutations occur in less than one tenth of de novo AML cases. Nevertheless, wild-type (wt) p53 dysfunction due to nonmutational p53 abnormalities appears to be rather frequent in various AML entities, bearing, presumably, a greater impact than is currently appreciated. Hereby, we advocate assessment of adult AML with respect to coexisting p53 alterations. Accordingly, we focus not only on the effects of mutant p53 oncogenic gain of function but also on the mechanisms underlying nonmutational wtp53 inactivation, which might be of therapeutic relevance. Patient-specific TP53 genotyping with functional evaluation of p53 protein may contribute significantly to the precise assessment of p53 status in AML, thus leading to the tailoring of a rationalized and precision p53-based therapy. The resolution of the mechanisms underlying p53 dysfunction will better address the p53-targeted therapies that are currently considered for AML. Additionally, a suggested novel algorithm for p53-based diagnostic workup in AML is presented, aiming at facilitating the p53-based therapeutic choices.
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MESH Headings
- Adult
- Animals
- Antineoplastic Agents/pharmacology
- Antineoplastic Agents/therapeutic use
- DNA Damage/drug effects
- Gene Expression Regulation, Leukemic/drug effects
- Genomic Instability/drug effects
- Hematopoiesis/drug effects
- Humans
- Karyopherins/genetics
- Karyopherins/metabolism
- Leukemia, Myeloid, Acute/diagnosis
- Leukemia, Myeloid, Acute/drug therapy
- Leukemia, Myeloid, Acute/genetics
- Leukemia, Myeloid, Acute/metabolism
- MicroRNAs/genetics
- MicroRNAs/metabolism
- Molecular Targeted Therapy/methods
- Mutation/drug effects
- Nuclear Proteins/genetics
- Nuclear Proteins/metabolism
- Nucleophosmin
- Protein Interaction Maps/drug effects
- Receptors, Cytoplasmic and Nuclear/genetics
- Receptors, Cytoplasmic and Nuclear/metabolism
- Signal Transduction/drug effects
- Translocation, Genetic
- Tumor Suppressor Protein p53/analysis
- Tumor Suppressor Protein p53/genetics
- Tumor Suppressor Protein p53/metabolism
- fms-Like Tyrosine Kinase 3/genetics
- fms-Like Tyrosine Kinase 3/metabolism
- Exportin 1 Protein
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Affiliation(s)
- Miron Prokocimer
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel; and
| | - Alina Molchadsky
- Department of Molecular Cell Biology, The Weizmann Institute of Science, Rehovot, Israel
| | - Varda Rotter
- Department of Molecular Cell Biology, The Weizmann Institute of Science, Rehovot, Israel
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Pereira B, Billaud M, Almeida R. RNA-Binding Proteins in Cancer: Old Players and New Actors. Trends Cancer 2017; 3:506-528. [PMID: 28718405 DOI: 10.1016/j.trecan.2017.05.003] [Citation(s) in RCA: 466] [Impact Index Per Article: 66.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 05/04/2017] [Accepted: 05/05/2017] [Indexed: 12/15/2022]
Abstract
RNA-binding proteins (RBPs) are key players in post-transcriptional events. The combination of versatility of their RNA-binding domains with structural flexibility enables RBPs to control the metabolism of a large array of transcripts. Perturbations in RBP-RNA networks activity have been causally associated with cancer development, but the rational framework describing these contributions remains fragmented. We review here the evidence that RBPs modulate multiple cancer traits, emphasize their functional diversity, and assess future trends in the study of RBPs in cancer.
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Affiliation(s)
- Bruno Pereira
- i3S - Institute for Research and Innovation in Health, University of Porto, 4200-135 Porto, Portugal; Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), 4200-465 Porto, Portugal.
| | - Marc Billaud
- Clinical and Experimental Model of Lymphomagenesis, Institut National de la Santé et de la Recherche Médicale (INSERM) Unité 1052, Centre National de la Recherche Scientifique (CNRS) Unité 5286, Centre Léon Bérard, Université Claude Bernard Lyon 1, Centre de Recherche en Cancérologie de Lyon, Lyon, France
| | - Raquel Almeida
- i3S - Institute for Research and Innovation in Health, University of Porto, 4200-135 Porto, Portugal; Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), 4200-465 Porto, Portugal; Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal; Biology Department, Faculty of Sciences of the University of Porto, 4169-007 Porto, Portugal
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Blewett NH, Iben JR, Gaidamakov S, Maraia RJ. La Deletion from Mouse Brain Alters Pre-tRNA Metabolism and Accumulation of Pre-5.8S rRNA, with Neuron Death and Reactive Astrocytosis. Mol Cell Biol 2017; 37:e00588-16. [PMID: 28223366 PMCID: PMC5477551 DOI: 10.1128/mcb.00588-16] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 12/01/2016] [Accepted: 02/06/2017] [Indexed: 12/20/2022] Open
Abstract
Human La antigen (Sjögren's syndrome antigen B [SSB]) is an abundant multifunctional RNA-binding protein. In the nucleoplasm, La binds to and protects from 3' exonucleases, the ends of precursor tRNAs, and other transcripts synthesized by RNA polymerase III and facilitates their maturation, while a nucleolar isoform has been implicated in rRNA biogenesis by multiple independent lines of evidence. We showed previously that conditional La knockout (La cKO) from mouse cortex neurons results in defective tRNA processing, although the pathway(s) involved in neuronal loss thereafter was unknown. Here, we demonstrate that La is stably associated with a spliced pre-tRNA intermediate. Microscopic evidence of aberrant nuclear accumulation of 5.8S rRNA in La cKO is supported by a 10-fold increase in a pre-5.8S rRNA intermediate. To identify pathways involved in subsequent neurodegeneration and loss of brain mass in the cKO cortex, we employed mRNA sequencing (mRNA-Seq), immunohistochemistry, and other approaches. This revealed robust enrichment of immune and astrocyte reactivity in La cKO cortex. Immunohistochemistry, including temporal analyses, demonstrated neurodegeneration, followed by astrocyte invasion associated with immune response and decreasing cKO cortex size over time. Thus, deletion of La from postmitotic neurons results in defective pre-tRNA and pre-rRNA processing and progressive neurodegeneration with loss of cortical brain mass.
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Affiliation(s)
- Nathan H Blewett
- Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Rockville, Maryland, USA
| | - James R Iben
- Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Rockville, Maryland, USA
| | - Sergei Gaidamakov
- Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Rockville, Maryland, USA
| | - Richard J Maraia
- Commissioned Corps, U.S. Public Health Service, Rockville, Maryland, USA
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Sommer G, Fedarovich A, Kota V, Rodriguez R, Smith CD, Heise T. Applying a high-throughput fluorescence polarization assay for the discovery of chemical probes blocking La:RNA interactions in vitro and in cells. PLoS One 2017; 12:e0173246. [PMID: 28291789 PMCID: PMC5349447 DOI: 10.1371/journal.pone.0173246] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 02/18/2017] [Indexed: 12/14/2022] Open
Abstract
The RNA-binding protein La is overexpressed in a number of tumor tissues and is thought to support tumorigenesis by binding to and facilitating the expression of mRNAs encoding tumor-promoting and anti-apoptotic factors. Hence, small molecules able to block the binding of La to specific RNAs could have a therapeutic impact by reducing the expression of tumor-promoting and anti-apoptotic factors. Toward this novel therapeutic strategy, we aimed to develop a high-throughput fluorescence polarization assay to screen small compound libraries for molecules blocking the binding of La to an RNA element derived from cyclin D1 mRNA. Herein, we make use of a robust fluorescence polarization assay and the validation of primary hits by electrophoretic mobility shift assays. We showed recently that La protects cells against cisplatin treatment by stimulating the protein synthesis of the anti-apoptotic factor Bcl2. Here, we show by RNA immunoprecipitation experiments that one small compound specifically impairs the association of La with Bcl2 mRNA in cells and sensitizes cells for cipslatin-induced cell death. In summary, we report the application of a high-throughput fluorescence polarization assay to identify small compounds that impair the binding of La to target RNAs in vitro and in cells.
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Affiliation(s)
- Gunhild Sommer
- Medical University of South Carolina, Department of Biochemistry & Molecular Biology, 173 Ashley Avenue, Charleston, SC, United States of America
| | - Alena Fedarovich
- Medical University of South Carolina, Department of Biochemistry & Molecular Biology, 173 Ashley Avenue, Charleston, SC, United States of America
| | - Venkatesh Kota
- Medical University of South Carolina, Department of Biochemistry & Molecular Biology, 173 Ashley Avenue, Charleston, SC, United States of America
| | - Reycel Rodriguez
- Medical University of South Carolina, Department of Biochemistry & Molecular Biology, 173 Ashley Avenue, Charleston, SC, United States of America
| | - Charles D. Smith
- Department of Pharmaceutical and Biomedical Sciences, 173 Ashley Avenue, Charleston, SC, United States of America
| | - Tilman Heise
- Medical University of South Carolina, Department of Biochemistry & Molecular Biology, 173 Ashley Avenue, Charleston, SC, United States of America
- * E-mail:
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Brown KA, Sharifi S, Hussain R, Donaldson L, Bayfield MA, Wilson DJ. Distinct Dynamic Modes Enable the Engagement of Dissimilar Ligands in a Promiscuous Atypical RNA Recognition Motif. Biochemistry 2016; 55:7141-7150. [PMID: 27959512 DOI: 10.1021/acs.biochem.6b00995] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Conformational dynamics play a critical role in ligand binding, often conferring divergent activities and specificities even in species with highly similar ground-state structures. Here, we employ time-resolved electrospray ionization hydrogen-deuterium exchange (TRESI-HDX) to characterize the changes in dynamics that accompany oligonucleotide binding in the atypical RNA recognition motif (RRM2) in the C-terminal domain (CTD) of human La protein. Using this approach, which is uniquely capable of probing changes in the structure and dynamics of weakly ordered regions of proteins, we reveal that binding of RRM2 to a model 23-mer single-stranded RNA and binding of RRM2 to structured IRES domain IV of the hepatitis C viral (HCV) RNA are driven by fundamentally different dynamic processes. In particular, binding of the single-stranded RNA induces helical "unwinding" in a region of the CTD previously hypothesized to play an important role in La and La-related protein-associated RNA remodeling, while the same region becomes less dynamic upon engagement with the double-stranded HCV RNA. Binding of double-stranded RNA also involves less penetration into the RRM2 binding pocket and more engagement with the unstructured C-terminus of the La CTD. The complementarity between TRESI-HDX and Δδ nuclear magnetic resonance measurements for ligand binding analysis is also explored.
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Affiliation(s)
- Kerene A Brown
- Department of Chemistry, York University , Toronto, ON M3J 1P3, Canada
- Centre for Research in Mass Spectrometry, York University , Toronto, ON M3J 1P3, Canada
| | - Samel Sharifi
- Department of Biology, York University , Toronto, ON M3J 1P3, Canada
| | - Rawaa Hussain
- Department of Biology, York University , Toronto, ON M3J 1P3, Canada
| | - Logan Donaldson
- Department of Biology, York University , Toronto, ON M3J 1P3, Canada
| | - Mark A Bayfield
- Department of Biology, York University , Toronto, ON M3J 1P3, Canada
- Centre for Research in Biomolecular Interactions, York University , Toronto, ON M3J 1P3, Canada
| | - Derek J Wilson
- Department of Chemistry, York University , Toronto, ON M3J 1P3, Canada
- Centre for Research in Mass Spectrometry, York University , Toronto, ON M3J 1P3, Canada
- Centre for Research in Biomolecular Interactions, York University , Toronto, ON M3J 1P3, Canada
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45
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Trino S, De Luca L, Laurenzana I, Caivano A, Del Vecchio L, Martinelli G, Musto P. P53-MDM2 Pathway: Evidences for A New Targeted Therapeutic Approach in B-Acute Lymphoblastic Leukemia. Front Pharmacol 2016; 7:491. [PMID: 28018226 PMCID: PMC5159974 DOI: 10.3389/fphar.2016.00491] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 11/30/2016] [Indexed: 11/13/2022] Open
Abstract
The tumor suppressor p53 is a canonical regulator of different biological functions, like apoptosis, cell cycle arrest, DNA repair, and genomic stability. This gene is frequently altered in human tumors generally by point mutations or deletions. Conversely, in acute lymphoblastic leukemia (ALL) genomic alterations of TP53 are rather uncommon, and prevalently occur in patients at relapse or with poor prognosis. On the other hand, p53 pathway is often compromised by the inactivation of its regulatory proteins, as MDM2 and ARF. MDM2 inhibitor molecules are able to antagonize p53-MDM2 interaction allowing p53 to exert tumor suppressor transcriptional regulation and to induce apoptotic pathways. Recent preclinical and clinical studies propose that MDM2 targeted therapy represents a promising anticancer strategy restoring p53 dependent mechanisms in ALL disease. Here, we discussed the use of new small molecule targeting p53 pathways as a promising drug target therapy in ALL.
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Affiliation(s)
- Stefania Trino
- Laboratory of Pre-Clinical and Translational Research, IRCCS - Referral Cancer Center of Basilicata Rionero in Vulture (PZ), Italy
| | - Luciana De Luca
- Laboratory of Pre-Clinical and Translational Research, IRCCS - Referral Cancer Center of Basilicata Rionero in Vulture (PZ), Italy
| | - Ilaria Laurenzana
- Laboratory of Pre-Clinical and Translational Research, IRCCS - Referral Cancer Center of Basilicata Rionero in Vulture (PZ), Italy
| | - Antonella Caivano
- Laboratory of Pre-Clinical and Translational Research, IRCCS - Referral Cancer Center of Basilicata Rionero in Vulture (PZ), Italy
| | - Luigi Del Vecchio
- CEINGE - Biotecnologie Avanzate S.C.a R.L.Naples, Italy; Department of Molecular Medicine and Medical Biotechnologies, Universita' degli Studi di Napoli Federico IINaples, Italy
| | - Giovanni Martinelli
- Department of Experimental, Diagnostic and Specialty Medicine, Institute of Hematology "L. and A. Seràgnoli," University of Bologna Bologna, Italy
| | - Pellegrino Musto
- Scientific Direction, IRCCS - Referral Cancer Center of Basilicata Rionero in Vulture (PZ), Italy
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Abstract
Since its discovery more than three decades ago, tumor suppressor p53 has been shown to play pivotal roles in both maintaining genomic integrity and tumor suppression. p53 functions as a transcription factor responding to a multitude of cellular stressors, regulating the transcription of many genes involved in cell-cycle arrest, senescence, autophagy, and apoptosis. Extensive work has revealed that p53 is one of the most commonly mutated tumor suppressor genes. The last three decades have demonstrated that p53 activity is controlled through transcriptional regulation and posttranslational modifications. However, evolving work is now uncovering that p53, and other p53 family members, are post-transcriptionally regulated by multiple RNA-binding proteins (RBPs). Understanding the regulation of p53 by RBPs may potentially open up the possibility for cancer therapeutic intervention. This review focuses on the posttranscriptional regulation of p53, and p53 family members, by RNA binding proteins and the reciprocal feedback pathways between several RNA-biding proteins modulating p53, and p53 family members.
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Affiliation(s)
- Chris Lucchesi
- Comparative Oncology Laboratory, School of Veterinary Medicine, School of Medicine, University of California at Davis, Davis, California 95616, USA
| | - Jin Zhang
- Comparative Oncology Laboratory, School of Veterinary Medicine, School of Medicine, University of California at Davis, Davis, California 95616, USA
| | - Xinbin Chen
- Comparative Oncology Laboratory, School of Veterinary Medicine, School of Medicine, University of California at Davis, Davis, California 95616, USA
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Seetharaman S, Flemyng E, Shen J, Conte MR, Ridley AJ. The RNA-binding protein LARP4 regulates cancer cell migration and invasion. Cytoskeleton (Hoboken) 2016; 73:680-690. [PMID: 27615744 PMCID: PMC5111583 DOI: 10.1002/cm.21336] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 09/06/2016] [Accepted: 09/07/2016] [Indexed: 01/07/2023]
Abstract
LARP4 is a La-related RNA-binding protein implicated in regulating mRNA translation, which interacts with poly(A)-binding protein (PABP). We previously identified LARP4 in an RNAi screen as one of several genes that regulate the shape of PC3 prostate cancer cells. Here we show that LARP4 depletion induces cell elongation in PC3 cells and MDA-MB-231 breast cancer cells. LARP4 depletion increases cell migration and invasion, as well as inducing invasive cell protrusions in 3D Matrigel. Conversely, LARP4 over-expression reduces cell elongation and increases cell circularity. LARP4 mutations are found in a variety of cancers. Introduction of some of these cancer-associated mutations, including a truncation mutant, into LARP4 enhances its effects on cell morphology. The truncation mutant shows enhanced interaction with PABP. We propose that LARP4 inhibits migration and invasion of cancer cells, and that some cancer-associated mutations stimulate these effects of LARP4. © 2016 The Authors. Cytoskeleton Published by Wiley Periodicals, Inc.
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Affiliation(s)
- Shailaja Seetharaman
- Randall Division of Cell and Molecular BiophysicsKing's College LondonNew Hunt's House, Guy's CampusLondonSE1 1ULUnited Kingdom
| | - Ella Flemyng
- Randall Division of Cell and Molecular BiophysicsKing's College LondonNew Hunt's House, Guy's CampusLondonSE1 1ULUnited Kingdom
| | - Jiazhen Shen
- Randall Division of Cell and Molecular BiophysicsKing's College LondonNew Hunt's House, Guy's CampusLondonSE1 1ULUnited Kingdom
| | - Maria R. Conte
- Randall Division of Cell and Molecular BiophysicsKing's College LondonNew Hunt's House, Guy's CampusLondonSE1 1ULUnited Kingdom
| | - Anne J. Ridley
- Randall Division of Cell and Molecular BiophysicsKing's College LondonNew Hunt's House, Guy's CampusLondonSE1 1ULUnited Kingdom
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Tongtawee T, Dechsukhum C, Leeanansaksiri W, Kaewpitoon S, Kaewpitoon N, Loyd RA, Matrakool L, Panpimanmas S. Genetic Polymorphism of MDM2 SNP309 in Patients with Helicobacter Pylori-Associated Gastritis. Asian Pac J Cancer Prev 2016; 16:7049-52. [PMID: 26514489 DOI: 10.7314/apjcp.2015.16.16.7049] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Helicobacter pylori plays an important role in gastric cancer, which has a relatively low inciduence in Thailand. MDM2 is a major negative regulator of p53, the key tumor suppressor involved in tumorigenesis of the majority of human cancers. Whether its expression might explain the relative lack of gastric cancer in Thailand was assessed here. MATERIALS AND METHODS This single-center study was conducted in the northeast region of Thailand. Gastric mucosa from 100 patients with Helicobacter pylori associated gastritis was analyzed for MDM2 SNP309 using real-time PCR hybridization (light-cycler) probes. RESULTS In the total 100 Helicobacter pylori associated gastritis cases the incidence of SNP 309 T/T homozygous was 78 % with SNP309 G/T heterozygous found in 19% and SNP309 G/G homozygous in 3%. The result show SNP 309 T/T and SNP 309 G/T to be rather common in the Thai population. CONCLUSIONS Our study indicates that the MDM2 SNP309 G/G homozygous genotype might be a risk factor for gastric cancer in Thailand and the fact that it is infrequent could explain to some extent the low incidence of gastric cancer in the Thai population.
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Affiliation(s)
- Taweesak Tongtawee
- Department of Surgery, Suranaree University of Technology, Nakhon Rachasima, Thailand E-mail :
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49
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Kota V, Sommer G, Durette C, Thibault P, van Niekerk EA, Twiss JL, Heise T. SUMO-Modification of the La Protein Facilitates Binding to mRNA In Vitro and in Cells. PLoS One 2016; 11:e0156365. [PMID: 27224031 PMCID: PMC4880191 DOI: 10.1371/journal.pone.0156365] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 05/12/2016] [Indexed: 02/05/2023] Open
Abstract
The RNA-binding protein La is involved in several aspects of RNA metabolism including the translational regulation of mRNAs and processing of pre-tRNAs. Besides its well-described phosphorylation by Casein kinase 2, the La protein is also posttranslationally modified by the Small Ubiquitin-like MOdifier (SUMO), but the functional outcome of this modification has not been defined. The objective of this study was to test whether sumoylation changes the RNA-binding activity of La. Therefore, we established an in vitro sumoylation assay for recombinant human La and analyzed its RNA-binding activity by electrophoretic mobility shift assays. We identified two novel SUMO-acceptor sites within the La protein located between the RNA recognition motif 1 and 2 and we demonstrate for the first time that sumoylation facilitates the RNA-binding of La to small RNA oligonucleotides representing the oligopyrimidine tract (TOP) elements from the 5' untranslated regions (UTR) of mRNAs encoding ribosomal protein L22 and L37 and to a longer RNA element from the 5' UTR of cyclin D1 (CCND1) mRNA in vitro. Furthermore, we show by RNA immunoprecipitation experiments that a La mutant deficient in sumoylation has impaired RNA-binding activity in cells. These data suggest that modulating the RNA-binding activity of La by sumoylation has important consequences on its functionality.
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Affiliation(s)
- Venkatesh Kota
- Medical University of South Carolina, Department of Biochemistry & Molecular Biology, Charleston, South Carolina, United States of America
| | - Gunhild Sommer
- Medical University of South Carolina, Department of Biochemistry & Molecular Biology, Charleston, South Carolina, United States of America
| | - Chantal Durette
- Institute of Research in Immunology and Cancer University de Montreal, Station Centre-ville, Montreal, Canada
| | - Pierre Thibault
- Institute of Research in Immunology and Cancer University de Montreal, Station Centre-ville, Montreal, Canada
| | - Erna A. van Niekerk
- Department of Neurosciences-0626, University of California, San Diego, La Jolla, California, United States of America
| | - Jeffery L. Twiss
- Department of Biological Sciences, University of South Carolina, Columbia, South Carolina, United States of America
| | - Tilman Heise
- Medical University of South Carolina, Department of Biochemistry & Molecular Biology, Charleston, South Carolina, United States of America
- * E-mail:
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Crivellaro S, Carrà G, Panuzzo C, Taulli R, Guerrasio A, Saglio G, Morotti A. The non-genomic loss of function of tumor suppressors: an essential role in the pathogenesis of chronic myeloid leukemia chronic phase. BMC Cancer 2016; 16:314. [PMID: 27184141 PMCID: PMC4869339 DOI: 10.1186/s12885-016-2346-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 05/09/2016] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Chronic Myeloid Leukemia was always referred as a unique cancer due to the apparent independence from tumor suppressors' deletions/mutations in the early stages of the disease. However, it is now well documented that even genetically wild-type tumor suppressors can be involved in tumorigenesis, when functionally inactivated. In particular, tumor suppressors' functions can be impaired by subtle variations of protein levels, changes in cellular compartmentalization and post-transcriptional/post-translational modifications, such as phosphorylation, acetylation, ubiquitination and sumoylation. Notably, tumor suppressors inactivation offers challenging therapeutic opportunities. The reactivation of an inactive and genetically wild-type tumor suppressor could indeed promote selective apoptosis of cancer cells without affecting normal cells. MAIN BODY Chronic Myeloid Leukemia (CML) could be considered as the paradigm for non-genomic loss of function of tumor suppressors due to the ability of BCR-ABL to directly promote functionally inactivation of several tumor suppressors. SHORT CONCLUSION In this review we will describe new insights on the role of FoxO, PP2A, p27, BLK, PTEN and other tumor suppressors in CML pathogenesis. Finally, we will describe strategies to promote tumor suppressors reactivation in CML.
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Affiliation(s)
- Sabrina Crivellaro
- Department of Clinical and Biological Sciences, University of Turin, San Luigi Hospital, Regione Gonzole 10, 10043, Orbassano, Italy
| | - Giovanna Carrà
- Department of Clinical and Biological Sciences, University of Turin, San Luigi Hospital, Regione Gonzole 10, 10043, Orbassano, Italy
| | - Cristina Panuzzo
- Department of Clinical and Biological Sciences, University of Turin, San Luigi Hospital, Regione Gonzole 10, 10043, Orbassano, Italy
| | - Riccardo Taulli
- Department of Oncology, University of Turin, Orbassano, Italy
| | - Angelo Guerrasio
- Department of Clinical and Biological Sciences, University of Turin, San Luigi Hospital, Regione Gonzole 10, 10043, Orbassano, Italy
| | - Giuseppe Saglio
- Department of Clinical and Biological Sciences, University of Turin, San Luigi Hospital, Regione Gonzole 10, 10043, Orbassano, Italy
| | - Alessandro Morotti
- Department of Clinical and Biological Sciences, University of Turin, San Luigi Hospital, Regione Gonzole 10, 10043, Orbassano, Italy.
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