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Michalak M, Golde V, Helm D, Kaltner H, Gebert J, Kopitz J. Combining Recombinase-Mediated Cassette Exchange Strategy with Quantitative Proteomic and Phosphoproteomic Analyses to Inspect Intracellular Functions of the Tumor Suppressor Galectin-4 in Colorectal Cancer Cells. Int J Mol Sci 2022; 23:ijms23126414. [PMID: 35742860 PMCID: PMC9223697 DOI: 10.3390/ijms23126414] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 06/03/2022] [Accepted: 06/06/2022] [Indexed: 12/18/2022] Open
Abstract
Galectin-4 (Gal4) has been suggested to function as a tumor suppressor in colorectal cancer (CRC). In order to systematically explore its function in CRC, we established a CRC cell line where Gal4 expression can be regulated via the doxycycline (dox)-inducible expression of a single copy wildtype LGALS4 transgene generated by recombinase-mediated cassette exchange (RMCE). Using this model and applying in-depth proteomic and phosphoproteomic analyses, we systematically screened for intracellular changes induced by Gal4 expression. Overall, 3083 cellular proteins and 2071 phosphosites were identified and quantified, of which 1603 could be matched and normalized to their protein expression levels. A bioinformatic analysis revealed that most of the regulated proteins and phosphosites can be localized in the nucleus and are categorized as nucleic acid-binding proteins. The top candidates whose expression was modulated by Gal4 are PURB, MAPKAPK3, BTF3 and BCAR1, while the prime candidates with altered phosphorylation included ZBTB7A, FOXK1, PURB and CK2beta. In order to validate the (phospho)proteomic data, we confirmed these candidates by a radiometric metabolic-labelling and immunoprecipitation strategy. All candidates exert functions in the transcriptional or translational control, indicating that Gal4 might be involved in these processes by affecting the expression or activity of these proteins.
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Affiliation(s)
- Malwina Michalak
- Department of Applied Tumor Biology, Institute of Pathology, Ruprecht-Karls-University Heidelberg, Im Neuenheimer Feld 224, 69120 Heidelberg, Germany; (M.M.); (V.G.); (J.K.)
- Clinical Cooperation Unit Applied Tumor Biology, German Cancer Research Center, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Viola Golde
- Department of Applied Tumor Biology, Institute of Pathology, Ruprecht-Karls-University Heidelberg, Im Neuenheimer Feld 224, 69120 Heidelberg, Germany; (M.M.); (V.G.); (J.K.)
| | - Dominik Helm
- Proteomics Core Facility, German Cancer Research Center, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany;
| | - Herbert Kaltner
- Veterinary Faculty, Institute of Physiological Chemistry, Ludwig-Maximilians-University, 80539 München, Germany;
| | - Johannes Gebert
- Department of Applied Tumor Biology, Institute of Pathology, Ruprecht-Karls-University Heidelberg, Im Neuenheimer Feld 224, 69120 Heidelberg, Germany; (M.M.); (V.G.); (J.K.)
- Clinical Cooperation Unit Applied Tumor Biology, German Cancer Research Center, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
- Correspondence:
| | - Jürgen Kopitz
- Department of Applied Tumor Biology, Institute of Pathology, Ruprecht-Karls-University Heidelberg, Im Neuenheimer Feld 224, 69120 Heidelberg, Germany; (M.M.); (V.G.); (J.K.)
- Clinical Cooperation Unit Applied Tumor Biology, German Cancer Research Center, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
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Fernandes J. Oncogenes: The Passport for Viral Oncolysis Through PKR Inhibition. BIOMARKERS IN CANCER 2016; 8:101-10. [PMID: 27486347 PMCID: PMC4966488 DOI: 10.4137/bic.s33378] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 06/28/2016] [Accepted: 07/07/2016] [Indexed: 02/07/2023]
Abstract
The transforming properties of oncogenes are derived from gain-of-function mutations, shifting cell signaling from highly regulated homeostatic to an uncontrolled oncogenic state, with the contribution of the inactivating mutations in tumor suppressor genes P53 and RB, leading to tumor resistance to conventional and target-directed therapy. On the other hand, this scenario fulfills two requirements for oncolytic virus infection in tumor cells: inactivation of tumor suppressors and presence of oncoproteins, also the requirements to engage malignancy. Several of these oncogenes have a negative impact on the main interferon antiviral defense, the double-stranded RNA-activated protein kinase (PKR), which helps viruses to spontaneously target tumor cells instead of normal cells. This review is focused on the negative impact of overexpression of oncogenes on conventional and targeted therapy and their positive impact on viral oncolysis due to their ability to inhibit PKR-induced translation blockage, allowing virion release and cell death.
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Affiliation(s)
- Janaina Fernandes
- NUMPEX-BIO, Campus Xerém, Federal University of Rio de Janeiro, Duque de Caxias, Rio de Janeiro, Brazil.; Institute for Translational Research on Health and Environment in the Amazon Region-INPeTAm, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
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