In:
Cancer Research, American Association for Cancer Research (AACR), Vol. 77, No. 13_Supplement ( 2017-07-01), p. 700-700
Abstract:
Alveolar rhabdomyosarcoma (aRMS) is a highly malicious childhood malignancy characterized by a specific chromosomal translocation encoding the oncogenic transcription factor PAX3-FOXO1. As aRMS cells are addicted to the tumor-specific fusion protein, it may serve as an ideal therapeutic target. Previously, we have identified from a large drug library screen the compound Fenretinide (retinoic acid p-hydroxyanilide), which is already in clinical use, to affect both PAX3-FOXO1 expression as well as aRMS cell viability. The aim of this study was therefore to characterize the mode of action of Fenretinide in more detail. First, we were able to show that Fenretinide induced the generation of reactive oxygen species (ROS) in mitochondria. A more detailed characterization revealed that the Fenretinide-induced ROS derived from an interaction of Fenretinide around complex II of the mitochondrial respiratory chain, leading to the production of superoxides. ROS scavenging as well as complexing of iron ions completely abolished cell death. To identify the mode of cell death involved, we then used a range of pharmacological inhibitors of specific cell death pathways including Z-vad (pan -caspase inhibitor), Necrostatin-1 (necroptosis pathway inhibitor (RIP-1 kinase inhibitor)), 3-Methyadenine (3-MA) (autophagy pathway inhibitor (phosphatidylinositol 3-kinase inhibitor)) and Ferrostatin (ferroptosis pathway inhibitor) during Fenretinide treatment. Surprisingly, none of these inhibitors alone was able to prevent cell death and even different combinations were not sufficient to completely inhibit cell death. CRISPR/Cas9 mediated depletion of key players in the apoptotic and necroptotic pathway (Bak, Bax and RIPK1) confirmed the pharmacological data. We therefore conclude that other, less characterized cell death pathways or a combination of several pathways including apoptosis and necroptosis might be crucial. Interestingly, electron microscopic examination of cells pointed towards an excessive accumulation of vacuoles to be characteristic. Taken together, our data show that Fenretinide shows high potential for the treatment of aRMS, inducing several forms of cell death mediated through the production of ROS. These properties open the search for additional compounds acting in a combinatorial manner. Citation Format: Eva Brack, Marco Wachtel, Beat W. Schaefer. Characterization of the mode of action of Fenretinide treatment in alveolar rhabdomyosarcoma cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 700. doi:10.1158/1538-7445.AM2017-700
Type of Medium:
Online Resource
ISSN:
0008-5472
,
1538-7445
DOI:
10.1158/1538-7445.AM2017-700
Language:
English
Publisher:
American Association for Cancer Research (AACR)
Publication Date:
2017
detail.hit.zdb_id:
2036785-5
detail.hit.zdb_id:
1432-1
detail.hit.zdb_id:
410466-3
