Cargando…

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...

Descripción completa

Detalles Bibliográficos
Autores principales: Bagnjuk, Konstantin, Kast, Verena Jasmin, Tiefenbacher, Astrid, Kaseder, Melanie, Yanase, Toshihiko, Burges, Alexander, Kunz, Lars, Mayr, Doris, Mayerhofer, Artur
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2019
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
_version_ 1783443853207928832
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
work_keys_str_mv AT bagnjukkonstantin inhibitorofapoptosisproteinsarepotentialtargetsfortreatmentofgranulosacelltumorsimplicationsfromstudiesinkgn
AT kastverenajasmin inhibitorofapoptosisproteinsarepotentialtargetsfortreatmentofgranulosacelltumorsimplicationsfromstudiesinkgn
AT tiefenbacherastrid inhibitorofapoptosisproteinsarepotentialtargetsfortreatmentofgranulosacelltumorsimplicationsfromstudiesinkgn
AT kasedermelanie inhibitorofapoptosisproteinsarepotentialtargetsfortreatmentofgranulosacelltumorsimplicationsfromstudiesinkgn
AT yanasetoshihiko inhibitorofapoptosisproteinsarepotentialtargetsfortreatmentofgranulosacelltumorsimplicationsfromstudiesinkgn
AT burgesalexander inhibitorofapoptosisproteinsarepotentialtargetsfortreatmentofgranulosacelltumorsimplicationsfromstudiesinkgn
AT kunzlars inhibitorofapoptosisproteinsarepotentialtargetsfortreatmentofgranulosacelltumorsimplicationsfromstudiesinkgn
AT mayrdoris inhibitorofapoptosisproteinsarepotentialtargetsfortreatmentofgranulosacelltumorsimplicationsfromstudiesinkgn
AT mayerhoferartur inhibitorofapoptosisproteinsarepotentialtargetsfortreatmentofgranulosacelltumorsimplicationsfromstudiesinkgn