Untersuchung zum Einfluss von HSP90 und FKBP51 in der Pathogenese des Cushing-Syndroms
Zusammenfassung der Projektergebnisse
The overall objective of this project had been the elucidation of biochemical interactions between Heat shock proteins (Hsp) and factors including FKBP51, and GR, as well as SREBP1 and CREB that control the production of ACTH and cortisol in corticotroph and adrenocortical cells. Together, these results should open possibilities to modulate function and growth of ACTH‐ and cortisol‐secreting tumors by HSP inhibition. Cushing´s Disease (CD) is caused by adrenocorticotropic hormone (ACTH)‐secreting pituitary tumours. They express high levels of heat shock protein (HSP) 90 and heat shock factor 1 (HSF1) in comparison to the normal tissue counterpart, indicating activated cellular stress. We aimed to correlate HSF1 expression with clinical features and hormonal/radiological findings of CD and to investigate the effects of HSF1 inhibition as a target for CD treatment. We examined the expression of total and pSer326HSF1 (as a marker for its transcriptional activation) by western blot on eight human CD tumours and compared to the HSF1 status of normal pituitary. We screened a cohort of 45 patients with CD for HSF1 by immunohistochemistry and correlated the HSF1 immunoreactivity score with the available clinical data. We evaluated the effects of HSF1 silencing with RNA interference and the HSF1 inhibitor KRIBB11 in AtT‐20 cells and four primary cultures of human corticotroph tumours. We show that HSF1 protein is highly expressed and transcriptionally active in CD tumours in comparison to normal pituitary. Immunoreactivity score for HSF1 did not correlate with the typical clinical features of the disease. HSF1 inhibition reduced proopiomelanocortin (Pomc) transcription in AtT‐20 cells. The HSF1 inhibitor KRIBB11 suppressed ACTH synthesis from 75% of human CD tumours in primary cell culture. This inhibitory action on Pomc transcription was mediated by increased glucocorticoid receptor (GR) and suppressed Nurr77/Nurr1 and AP‐1 transcriptional activities. These data show that HSF1 regulates POMC transcription. Pharmacological targeting of HSF1 may be a promising treatment option for the control of excess ACTH secretion in CD. Adrenocortical carcinoma (ACC) is a rare tumor entity with restricted therapeutic opportunities. HSP90 (Heat Shock Protein 90) chaperone activity is fundamental for cell survival and contributes to different oncogenic signaling pathways. Indeed, agents targeting HSP90 function have shown therapeutic efficacy in several cancer types. We have examined the expression of HSP90 in different adrenal tumors and evaluated the use of HSP90 inhibitors in vitro as possible therapy for ACC. Immunohistochemical expression of HSP90 isoforms was investigated in different adrenocortical tumors and associated with clinical features. Additionally, a panel of N‐terminal (17‐allylamino‐17‐demethoxygeldanamycin (17‐AAG), luminespib and ganetespib) and C‐terminal (novobiocin and silibinin) HSP90 inhibitors were tested on various ACC cell lines. Within adrenocortical tumors, ACC samples exhibited the highest expression of HSP90β. Within a cohort of ACC patients, HSP90β expression levels were inversely correlated with recurrence‐free and overall survival. In functional assays, among five different compounds tested luminespib and ganetespib induced a significant decrease in cell viability in single as well as in combined treatments with compounds of the clinically used EDP‐M scheme (etoposide, doxorubicin, cisplatin, mitotane). Inhibition of cell viability correlated furthermore with a decrease in proliferation, in cell migration and an increase in apoptosis. Moreover, analysis of cancer pathways indicated a modulation of the ERK1/2‐ and AKT‐pathways by luminespib and ganetespib treatment. In summary, new generation N‐terminal HSP90 inhibitors hold promise as agents with anti‐tumor properties against adrenocortical cancer cells. Furthermore, low expression of HSP90β could be used as prognostic marker for ACC patients. Following subsequent studies in appropriate preclinical models could pave the way towards the introduction of N‐terminal HSP90 inhibitors in the treatment of patients with ACC.
Projektbezogene Publikationen (Auswahl)
- HSP90 inhibitors as potential treatment options against adrenocortical carcinoma. 60. Deutscher Kongress für Endokrinologie, 15–17 March 2017, Würzburg, Germany
Ciato D, Siebert C, Li R, Shapiro I, Monteserin‐Garcia JL, Hantel C, Stalla GK and Beuschlein F
- The molecular chaperone Heat shock protein 90 (Hsp90) as novel therapeutic target for the treatment of adrenocortical carcinoma (ACC). 16th ENSAT Meeting 2017, Paris, France
Claudia Siebert, Denis Ciato, Ran Li, Jose Luis Monteserin‐Garcia, Günter K. Stalla, Constanze Hantel and Felix Beuschlein
- Effects on cellular processes and potent anti‐tumoral properties of several Hsp90 inhibitors in adrenocortical carcinoma. 18th Adrenal cortex conference, Munich, Germany
Claudia Siebert, Denis Ciato, Jose Luis Monteserin‐Garcia, Igor Shapiro, Günter K. Stalla, Constanze Hantel and Felix Beuschlein
- Inhibition of HSF1 activity as a potential therapeutic target for Cushing Disease. 61. Deutscher Kongress für Endokrinologie. 14–16 March 2018, Bonn, Germany
Ciato D, Li R, Monteserin Garcia JL, Papst L, Theodoropoulou M, Tichomirowa M, Belaya Z, Buchfelder M, Paez‐Pereda M and Stalla GK
- Inhibition of HSF1 suppresses POMC transcription by regulating suppressive mechanisms over its promoter. Eurpean Congress of the Neuroendocrine Association ENEA, 17‐20 October 2018, Wroclaw, Poland
Ciato D, Li R, Monteserin Garcia JL, Papst L, Hristov M, Tichomirowa M, Belaya Z, Buchfelder M, Honneger J, Fitsch J, Theodoropoulou M, Paez‐Pereda M and Stalla GK
- The molecular chaperone Heat shock protein 90 (Hsp90) as novel therapeutic target for the treatment of adrenocortical carcinoma (ACC) and Cushing syndrome. 17th ENSAT Meeting 2018, Florence, Italy
Claudia Siebert, Denis Ciato, Jose Luis Monteserin‐Garcia, Igor Shapiro, Günter K. Stalla, Constanze Hantel and Felix Beuschlein
- Inhibition of HSF1 enhances repressive molecular mechanisms on POMC promoter. Neuroendocrinology. 2019 Apr 16
Ciato D, Li R, Monteserin Garcia JL, Papst L, D'Annunzio S, Hristov M, Tichomirowa MA, Belaya Z, Rozhinskaya L, Buchfelder M, Theodoropoulou M, Paez‐Pereda M, Stalla GK
(Siehe online unter https://doi.org/10.1159/000500200)
