Histone Deacetylase Inhibitor SAHA Is a Promising Treatment of Cushing Disease

J Clin Endocrinol Metab. 2017 Aug 1;102(8):2825-2835. doi: 10.1210/jc.2017-00464.

Abstract

Context: Remission failure following transsphenoidal surgery in Cushing disease (CD) from pituitary corticotroph tumors (CtTs) remains clinically challenging. Histone deacetylase inhibitors (HDACis) are antitumor drugs approved for clinical use, with the potential to affect adrenocorticotropin hormone (ACTH) hypersecretion by inhibiting pro-opiomelanocortin (POMC) transcription.

Objective: Testing the efficacy of suberoylanilide hydroxamic acid (SAHA) on human and murine ACTH-secreting tumor (AtT-20) cells.

Design: Cell viability, ACTH secretion (enzyme-linked immunosorbent assay), apoptosis, and gene expression profile were investigated on AtT-20 cells. In vivo efficacy was examined in an athymic nude mouse AtT-20 xenograft model. SAHA efficacy against human-derived corticotroph tumor (hCtT) (n = 8) was tested in vitro.

Setting: National Institutes of Health.

Intervention: SAHA (0.5 to 8 µM).

Main outcome measures: AtT-20 and hCtT cell survival, in vitro/invivo ACTH measurements.

Results: SAHA (1 µM) reduced AtT-20 viability to 75% at 24 hours, 43% at 48 hours (analysis of variance; P = 0.002). Apoptosis was confirmed with elevated BAX/Bcl2 ratio and FACS. Intriguingly, early (3-hour) significant decline (70%; P < 0.0001) of secreted ACTH and diminished POMC transcription was observed with SAHA (1 µM). Microarray analysis revealed a direct association between liver X receptor alpha (LXRα) and POMC expression. Accordingly, SAHA reduced LXRα in AtT-20 cells but not in normal murine corticotrophs. Xenografted nude-mice tumor involution (126 ± 33/160 ± 35 vs 337 ± 49 mm3; P = 0.0005) was observed with 5-day intraperitoneal SAHA, with reversal of elevated ACTH (P < 0.0001). SAHA did not affect serum ACTH in nontumor mice. Lastly, we confirmed that SAHA (1 µM/24 h) decreased hCtT survival (78.92%; P = 0.0007) and ACTH secretion (83.64%; P = 0.03).

Conclusion: Our findings demonstrate SAHA's efficacy in reducing survival and ACTH secretion in AtT-20 and hCtT cells, providing a potential intervention for recurrent/unremitting CD.

Trial registration: ClinicalTrials.gov NCT00060541.

MeSH terms

  • ACTH-Secreting Pituitary Adenoma / drug therapy*
  • ACTH-Secreting Pituitary Adenoma / metabolism
  • Adenoma / drug therapy*
  • Adenoma / metabolism
  • Adrenocorticotropic Hormone / drug effects*
  • Adrenocorticotropic Hormone / metabolism
  • Animals
  • Apoptosis / drug effects*
  • Blotting, Western
  • Cell Line, Tumor
  • Cell Survival / drug effects
  • Corticotrophs / cytology
  • Corticotrophs / drug effects
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Flow Cytometry
  • Gene Expression Profiling
  • Histone Deacetylase Inhibitors / pharmacology*
  • Humans
  • Hydroxamic Acids / pharmacology*
  • In Vitro Techniques
  • Mice
  • Mice, Nude
  • Pituitary ACTH Hypersecretion / drug therapy*
  • Pro-Opiomelanocortin / drug effects
  • Pro-Opiomelanocortin / genetics
  • Real-Time Polymerase Chain Reaction
  • Vorinostat
  • Xenograft Model Antitumor Assays

Substances

  • Histone Deacetylase Inhibitors
  • Hydroxamic Acids
  • Vorinostat
  • Pro-Opiomelanocortin
  • Adrenocorticotropic Hormone

Associated data

  • ClinicalTrials.gov/NCT00060541