Pituitary adenomas evade apoptosis via noxa deregulation in Cushing's disease

Cell Rep. 2022 Aug 23;40(8):111223. doi: 10.1016/j.celrep.2022.111223.

Abstract

Sporadic pituitary adenomas occur in over 10% of the population. Hormone-secreting adenomas, including those causing Cushing's disease (CD), cause severe morbidity and early mortality. Mechanistic studies of CD are hindered by a lack of in vitro models and control normal human pituitary glands. Here, we surgically annotate adenomas and adjacent normal glands in 25 of 34 patients. Using single-cell RNA sequencing (RNA-seq) analysis of 27594 cells, we identify CD adenoma transcriptomic signatures compared with adjacent normal cells, with validation by bulk RNA-seq, DNA methylation, qRT-PCR, and immunohistochemistry. CD adenoma cells include a subpopulation of proliferating, terminally differentiated corticotrophs. In CD adenomas, we find recurrent promoter hypomethylation and transcriptional upregulation of PMAIP1 (encoding pro-apoptotic BH3-only bcl-2 protein noxa) but paradoxical noxa downregulation. Using primary CD adenoma cell cultures and a corticotroph-enriched mouse cell line, we find that selective proteasomal inhibition with bortezomib stabilizes noxa and induces apoptosis, indicating its utility as an anti-tumor agent.

Keywords: CP: Cancer; CP: Molecular biology; Cushing’s disease; DNA methylation; bortezomib; preclinical testing; proteasome; single-cell RNA-seq; sporadic pituitary adenoma.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, N.I.H., Intramural

MeSH terms

  • Adenoma* / metabolism
  • Adrenocorticotropic Hormone / metabolism
  • Animals
  • Apoptosis
  • Humans
  • Mice
  • Pituitary ACTH Hypersecretion* / genetics
  • Pituitary ACTH Hypersecretion* / pathology
  • Pituitary Neoplasms* / genetics
  • Pituitary Neoplasms* / metabolism
  • Pituitary Neoplasms* / pathology

Substances

  • Adrenocorticotropic Hormone