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Jbara A, Lin KT, Stossel C, Siegfried Z, Shqerat H, Amar-Schwartz A, Elyada E, Mogilevsky M, Raitses-Gurevich M, Johnson JL, Yaron TM, Ovadia O, Jang GH, Danan-Gotthold M, Cantley LC, Levanon EY, Gallinger S, Krainer AR, Golan T, Karni R. RBFOX2 modulates a metastatic signature of alternative splicing in pancreatic cancer. Nature 2023; 617:147-153. [PMID: 36949200 PMCID: PMC10156590 DOI: 10.1038/s41586-023-05820-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 02/10/2023] [Indexed: 03/24/2023]
Abstract
Pancreatic ductal adenocarcinoma (PDA) is characterized by aggressive local invasion and metastatic spread, leading to high lethality. Although driver gene mutations during PDA progression are conserved, no specific mutation is correlated with the dissemination of metastases1-3. Here we analysed RNA splicing data of a large cohort of primary and metastatic PDA tumours to identify differentially spliced events that correlate with PDA progression. De novo motif analysis of these events detected enrichment of motifs with high similarity to the RBFOX2 motif. Overexpression of RBFOX2 in a patient-derived xenograft (PDX) metastatic PDA cell line drastically reduced the metastatic potential of these cells in vitro and in vivo, whereas depletion of RBFOX2 in primary pancreatic tumour cell lines increased the metastatic potential of these cells. These findings support the role of RBFOX2 as a potent metastatic suppressor in PDA. RNA-sequencing and splicing analysis of RBFOX2 target genes revealed enrichment of genes in the RHO GTPase pathways, suggesting a role of RBFOX2 splicing activity in cytoskeletal organization and focal adhesion formation. Modulation of RBFOX2-regulated splicing events, such as via myosin phosphatase RHO-interacting protein (MPRIP), is associated with PDA metastases, altered cytoskeletal organization and the induction of focal adhesion formation. Our results implicate the splicing-regulatory function of RBFOX2 as a tumour suppressor in PDA and suggest a therapeutic approach for metastatic PDA.
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Affiliation(s)
- Amina Jbara
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Kuan-Ting Lin
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Chani Stossel
- Division of Oncology, Sheba Medical Center Tel Hashomer, Ramat-Gan, Israel
| | - Zahava Siegfried
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Haya Shqerat
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Adi Amar-Schwartz
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Ela Elyada
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Maxim Mogilevsky
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | | | - Jared L Johnson
- Meyer Cancer Center, Weill Cornell Medicine, New York, NY, USA
- Department of Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Tomer M Yaron
- Meyer Cancer Center, Weill Cornell Medicine, New York, NY, USA
- Department of Medicine, Weill Cornell Medicine, New York, NY, USA
- Englander Institute for Precision Medicine, Institute for Computational Biomedicine, Weill Cornell Medicine, New York, NY, USA
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY, USA
| | - Ofek Ovadia
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Gun Ho Jang
- Department of Surgery, University of Toronto, Toronto, Ontario, Canada
| | - Miri Danan-Gotthold
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - Lewis C Cantley
- Meyer Cancer Center, Weill Cornell Medicine, New York, NY, USA
- Department of Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Erez Y Levanon
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - Steven Gallinger
- Department of Surgery, University of Toronto, Toronto, Ontario, Canada
| | | | - Talia Golan
- Division of Oncology, Sheba Medical Center Tel Hashomer, Ramat-Gan, Israel
| | - Rotem Karni
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, Israel.
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Amar-Schwartz A, Ben Hur V, Jbara A, Cohen Y, Barnabas GD, Arbib E, Siegfried Z, Mashahreh B, Hassouna F, Shilo A, Abu-Odeh M, Berger M, Wiener R, Aqeilan R, Geiger T, Karni R. S6K1 phosphorylates Cdk1 and MSH6 to regulate DNA repair. eLife 2022; 11:79128. [PMID: 36189922 PMCID: PMC9529248 DOI: 10.7554/elife.79128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 08/26/2022] [Indexed: 11/22/2022] Open
Abstract
The mTORC1 substrate, S6 Kinase 1 (S6K1), is involved in the regulation of cell growth, ribosome biogenesis, glucose homeostasis, and adipogenesis. Accumulating evidence has suggested a role for mTORC1 signaling in the DNA damage response. This is mostly based on the findings that mTORC1 inhibitors sensitized cells to DNA damage. However, a direct role of the mTORC1-S6K1 signaling pathway in DNA repair and the mechanism by which this signaling pathway regulates DNA repair is unknown. In this study, we discovered a novel role for S6K1 in regulating DNA repair through the coordinated regulation of the cell cycle, homologous recombination (HR) DNA repair (HRR) and mismatch DNA repair (MMR) mechanisms. Here, we show that S6K1 orchestrates DNA repair by phosphorylation of Cdk1 at serine 39, causing G2/M cell cycle arrest enabling homologous recombination and by phosphorylation of MSH6 at serine 309, enhancing MMR. Moreover, breast cancer cells harboring RPS6KB1 gene amplification show increased resistance to several DNA damaging agents and S6K1 expression is associated with poor survival of breast cancer patients treated with chemotherapy. Our findings reveal an unexpected function of S6K1 in the DNA repair pathway, serving as a tumorigenic barrier by safeguarding genomic stability. Damage to the DNA in our cells can cause harmful changes that, if unchecked, can lead to the development of cancer. To help prevent this, cellular mechanisms are in place to repair defects in the DNA. A particular process, known as the mTORC1-S6K1 pathway is suspected to be important for repair because when this pathway is blocked, cells become more sensitive to DNA damage. It is still unknown how the various proteins involved in the mTORC1-S6K1 pathway contribute to repairing DNA. One of these proteins, S6K1, is an enzyme involved in coordinating cell growth and survival. The tumor cells in some forms of breast cancer produce more of this protein than normal, suggesting that S6K1 benefits these cells’ survival. However, it is unclear exactly how the enzyme does this. Amar-Schwartz, Ben-Hur, Jbara et al. studied the role of S6K1 using genetically manipulated mouse cells and human cancer cells. These experiments showed that the protein interacts with two other proteins involved in DNA repair and activates them, regulating two different repair mechanisms and protecting cells against damage. These results might explain why some breast cancer tumors are resistant to radiotherapy and chemotherapy treatments, which aim to kill tumor cells by damaging their DNA. If this is the case, these findings could help clinicians choose more effective treatment options for people with cancers that produce additional S6K1. In the future, drugs that block the activity of the enzyme could make cancer cells more susceptible to chemotherapy.
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Affiliation(s)
- Adi Amar-Schwartz
- Department of Biochemistry and Molecular Biology, the Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Vered Ben Hur
- Department of Biochemistry and Molecular Biology, the Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Amina Jbara
- Department of Biochemistry and Molecular Biology, the Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Yuval Cohen
- Department of Biochemistry and Molecular Biology, the Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Georgina D Barnabas
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Eliran Arbib
- Lautenberg Center for Immunology and Cancer Research, Department of Immunology and Cancer Research, the Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Zahava Siegfried
- Department of Biochemistry and Molecular Biology, the Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Bayan Mashahreh
- Department of Biochemistry and Molecular Biology, the Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Fouad Hassouna
- Department of Biochemistry and Molecular Biology, the Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Asaf Shilo
- Department of Biochemistry and Molecular Biology, the Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Mohammad Abu-Odeh
- Lautenberg Center for Immunology and Cancer Research, Department of Immunology and Cancer Research, the Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Michael Berger
- Lautenberg Center for Immunology and Cancer Research, Department of Immunology and Cancer Research, the Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Reuven Wiener
- Department of Biochemistry and Molecular Biology, the Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Rami Aqeilan
- Lautenberg Center for Immunology and Cancer Research, Department of Immunology and Cancer Research, the Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Tamar Geiger
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Rotem Karni
- Department of Biochemistry and Molecular Biology, the Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, Israel
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Jbara A, Siegfried Z, Karni R. Splice-switching as cancer therapy. Curr Opin Pharmacol 2021; 59:140-148. [PMID: 34217945 DOI: 10.1016/j.coph.2021.05.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 05/25/2021] [Accepted: 05/26/2021] [Indexed: 12/26/2022]
Abstract
In light of recent advances in RNA splicing modulation as therapy for specific genetic diseases, there is great optimism that this approach can be applied to treatment of cancer as well. Dysregulation of alternative RNA splicing is a common aberration detected in many cancers and thus, provides an attractive target for therapeutics. Here, we present and compare two promising approaches that are currently being investigated to manipulate alternative splicing and their potential use in therapy. The first strategy makes use of splice-switching oligonucleotides, whereas the second strategy uses CRISPR (clustered regularly interspaced short palindromic repeat Cas (CRISPR-associated) technology. We will discuss both the challenges and limitations of these technologies and progress being made to implement splice-switching as a potential cancer therapy.
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Affiliation(s)
- Amina Jbara
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, 91120, Israel
| | - Zahava Siegfried
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, 91120, Israel
| | - Rotem Karni
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, 91120, Israel.
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Goldman-Wohl D, Greenfield C, Eisenberg-Loebl I, Denichenko P, Jbara A, Karni R, Ariel I, Yagel S. Trophoblast lineage specific expression of the alternative splicing factor RBFOX2 suggests a role in placental development. Placenta 2020; 100:142-149. [PMID: 32762877 DOI: 10.1016/j.placenta.2020.07.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Revised: 06/30/2020] [Accepted: 07/06/2020] [Indexed: 12/17/2022]
Abstract
INTRODUCTION RBFOX2, an RNA-binding protein, controls tissue-specific alternative splicing of exons in diverse processes of development. The progenitor cytotrophoblast of the human placenta differentiates into either the syncytiotrophoblast, formed via cell fusion, or the invasive extravillous trophoblast lineage. The placenta affords a singular system where a role for RBFOX2 in both cell invasion and cell fusion may be studied. We investigated a role for RBFOX2 in trophoblast cell differentiation, as a foundation for investigations of RBFOX2 in embryo implantation and placental development. METHODS Immunohistochemistry of RBFOX2 was performed on placental tissue sections from three trimesters of pregnancy and from pathological pregnancies. Primary trophoblast cell culture and immunofluorescence were employed to determine RBFOX2 expression upon cell fusion. Knockdown of RBFOX2 expression was performed with βhCG and syncytin-1 as molecular indicators of fusion. RESULTS In both normal and pathological placentas, RBFOX2 expression was confined to the cytotrophoblast and the extravillous trophoblast, but absent from the syncytiotrophoblast. Additionally, we showed that primary trophoblasts that spontaneously fused in cell culture downregulated RBFOX2 expression. In functional experiments, knockdown expression of RBFOX2 significantly upregulated βhCG, while the upregulation of syncytin-1 did not reach statistical significance. DISCUSSION RBFOX2, by conferring mRNA diversity, may act as a regulator switch in trophoblast differentiation to either the fusion or invasive pathways. By studying alternative splicing we further our understanding of placental development, yielding possible insights into preeclampsia, where expression of antiangiogenic isoforms produced through alternative splicing play a critical role in disease development and severity.
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Affiliation(s)
- Debra Goldman-Wohl
- The Magda and Richard Hoffman Center for Human Placenta Research, Department of Obstetrics and Gynecology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Caryn Greenfield
- The Magda and Richard Hoffman Center for Human Placenta Research, Department of Obstetrics and Gynecology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Iris Eisenberg-Loebl
- The Magda and Richard Hoffman Center for Human Placenta Research, Department of Obstetrics and Gynecology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Polina Denichenko
- IMRIC Hadassah-Hebrew University School of Medicine, Jerusalem, Israel
| | - Amina Jbara
- IMRIC Hadassah-Hebrew University School of Medicine, Jerusalem, Israel
| | - Rotem Karni
- IMRIC Hadassah-Hebrew University School of Medicine, Jerusalem, Israel
| | - Ilana Ariel
- Department of Pathology Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Simcha Yagel
- The Magda and Richard Hoffman Center for Human Placenta Research, Department of Obstetrics and Gynecology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel.
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