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Inhibitor of apoptosis proteins are potential targets for treatment of granulosa cell tumors – implications from studies in KGN
BACKGROUND: Granulosa cell tumors (GCTs) are derived from proliferating granulosa cells of the ovarian follicle. They are known for their late recurrence and most patients with an aggressive form die from their disease. There are no treatment options for this slowly proliferating tumor besides surge...
Autores principales: | , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
BioMed Central
2019
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6694575/ https://www.ncbi.nlm.nih.gov/pubmed/31412918 http://dx.doi.org/10.1186/s13048-019-0549-6 |
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author | Bagnjuk, Konstantin Kast, Verena Jasmin Tiefenbacher, Astrid Kaseder, Melanie Yanase, Toshihiko Burges, Alexander Kunz, Lars Mayr, Doris Mayerhofer, Artur |
author_facet | Bagnjuk, Konstantin Kast, Verena Jasmin Tiefenbacher, Astrid Kaseder, Melanie Yanase, Toshihiko Burges, Alexander Kunz, Lars Mayr, Doris Mayerhofer, Artur |
author_sort | Bagnjuk, Konstantin |
collection | PubMed |
description | BACKGROUND: Granulosa cell tumors (GCTs) are derived from proliferating granulosa cells of the ovarian follicle. They are known for their late recurrence and most patients with an aggressive form die from their disease. There are no treatment options for this slowly proliferating tumor besides surgery and chemotherapy. In a number of tumors, analogs of the second mitochondria-derived activator of caspases (SMAC), alone or in combination with other molecules, such as TNFα, are evolving as new treatment options. SMAC mimetics block inhibitor of apoptosis proteins (IAPs), which bind caspases (e.g. XIAP), or activate the pro-survival NF-κB pathway (e.g. cIAP1/2). Expression of IAPs by GCTs is yet not fully elucidated but recently XIAP and its inhibition by SMAC mimetics in a combination therapy was described to induce apoptosis in a GCT cell line, KGN. We evaluated the expression of cIAP1 in GCTs and elucidated the effects of the SMAC mimetic BV-6 using KGN as a model. RESULTS: Employing immunohistochemistry, we observed cIAP1 expression in a tissue microarray (TMA) of 42 GCT samples. RT-PCR confirmed expression of cIAP1/2, as well as XIAP, in primary, patient-derived GCTs and in KGN. We therefore tested the ability of the bivalent SMAC mimetic BV-6, which is known to inhibit cIAP1/2 and XIAP, to induce cell death in KGN. A dose response study indicated an EC(50) ≈ 8 μM for both, early (< 8) and advanced (> 80) passages, which differ in growth rate and presumably aggressiveness. Quantitative RT-PCR showed upregulation of NF-κB regulated genes in BV-6 stimulated cells. Blocking experiments with the pan-caspase inhibitor Z-VAD-FMK indicated caspase-dependence. A concentration of 20 μM Z-VAD-FMK was sufficient to significantly reduce apoptosis. This cell death was further substantiated by results of Western Blot studies. Cleaved caspase 3 and cleaved PARP became evident in the BV-6 treated group. CONCLUSIONS: Taken together, the results show that BV-6 is able to induce apoptosis in KGN cells. This approach may therefore offer a promising therapeutic avenue to treat GCTs. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s13048-019-0549-6) contains supplementary material, which is available to authorized users. |
format | Online Article Text |
id | pubmed-6694575 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2019 |
publisher | BioMed Central |
record_format | MEDLINE/PubMed |
spelling | pubmed-66945752019-08-19 Inhibitor of apoptosis proteins are potential targets for treatment of granulosa cell tumors – implications from studies in KGN Bagnjuk, Konstantin Kast, Verena Jasmin Tiefenbacher, Astrid Kaseder, Melanie Yanase, Toshihiko Burges, Alexander Kunz, Lars Mayr, Doris Mayerhofer, Artur J Ovarian Res Research BACKGROUND: Granulosa cell tumors (GCTs) are derived from proliferating granulosa cells of the ovarian follicle. They are known for their late recurrence and most patients with an aggressive form die from their disease. There are no treatment options for this slowly proliferating tumor besides surgery and chemotherapy. In a number of tumors, analogs of the second mitochondria-derived activator of caspases (SMAC), alone or in combination with other molecules, such as TNFα, are evolving as new treatment options. SMAC mimetics block inhibitor of apoptosis proteins (IAPs), which bind caspases (e.g. XIAP), or activate the pro-survival NF-κB pathway (e.g. cIAP1/2). Expression of IAPs by GCTs is yet not fully elucidated but recently XIAP and its inhibition by SMAC mimetics in a combination therapy was described to induce apoptosis in a GCT cell line, KGN. We evaluated the expression of cIAP1 in GCTs and elucidated the effects of the SMAC mimetic BV-6 using KGN as a model. RESULTS: Employing immunohistochemistry, we observed cIAP1 expression in a tissue microarray (TMA) of 42 GCT samples. RT-PCR confirmed expression of cIAP1/2, as well as XIAP, in primary, patient-derived GCTs and in KGN. We therefore tested the ability of the bivalent SMAC mimetic BV-6, which is known to inhibit cIAP1/2 and XIAP, to induce cell death in KGN. A dose response study indicated an EC(50) ≈ 8 μM for both, early (< 8) and advanced (> 80) passages, which differ in growth rate and presumably aggressiveness. Quantitative RT-PCR showed upregulation of NF-κB regulated genes in BV-6 stimulated cells. Blocking experiments with the pan-caspase inhibitor Z-VAD-FMK indicated caspase-dependence. A concentration of 20 μM Z-VAD-FMK was sufficient to significantly reduce apoptosis. This cell death was further substantiated by results of Western Blot studies. Cleaved caspase 3 and cleaved PARP became evident in the BV-6 treated group. CONCLUSIONS: Taken together, the results show that BV-6 is able to induce apoptosis in KGN cells. This approach may therefore offer a promising therapeutic avenue to treat GCTs. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s13048-019-0549-6) contains supplementary material, which is available to authorized users. BioMed Central 2019-08-14 /pmc/articles/PMC6694575/ /pubmed/31412918 http://dx.doi.org/10.1186/s13048-019-0549-6 Text en © The Author(s). 2019 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. |
spellingShingle | Research Bagnjuk, Konstantin Kast, Verena Jasmin Tiefenbacher, Astrid Kaseder, Melanie Yanase, Toshihiko Burges, Alexander Kunz, Lars Mayr, Doris Mayerhofer, Artur Inhibitor of apoptosis proteins are potential targets for treatment of granulosa cell tumors – implications from studies in KGN |
title | Inhibitor of apoptosis proteins are potential targets for treatment of granulosa cell tumors – implications from studies in KGN |
title_full | Inhibitor of apoptosis proteins are potential targets for treatment of granulosa cell tumors – implications from studies in KGN |
title_fullStr | Inhibitor of apoptosis proteins are potential targets for treatment of granulosa cell tumors – implications from studies in KGN |
title_full_unstemmed | Inhibitor of apoptosis proteins are potential targets for treatment of granulosa cell tumors – implications from studies in KGN |
title_short | Inhibitor of apoptosis proteins are potential targets for treatment of granulosa cell tumors – implications from studies in KGN |
title_sort | inhibitor of apoptosis proteins are potential targets for treatment of granulosa cell tumors – implications from studies in kgn |
topic | Research |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6694575/ https://www.ncbi.nlm.nih.gov/pubmed/31412918 http://dx.doi.org/10.1186/s13048-019-0549-6 |
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