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

• Published in: Cell reports (Cambridge) 2022-08, Vol.40 (8), p.111223-111223, Article 111223
• Main Authors: Asuzu, David T., Alvarez, Reinier, Fletcher, Patrick A., Mandal, Debjani, Johnson, Kory, Wu, Weiwei, Elkahloun, Abdel, Clavijo, Paul, Allen, Clint, Maric, Dragan, Ray-Chaudhury, Abhik, Rajan, Sharika, Abdullaev, Zied, Nwokoye, Diana, Aldape, Kenneth, Nieman, Lynnette K., Stratakis, Constantine, Stojilkovic, Stanko S., Chittiboina, Prashant
• Format: Article
• Language: English
• Subjects: bortezomib; Cushing’s disease; DNA methylation; preclinical testing; proteasome; single-cell RNA-seq; sporadic pituitary adenoma
• ISSN: 2211-1247; 2211-1247
• DOI: 10.1016/j.celrep.2022.111223

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. [Display omitted] •scRNA-seq indicates transcriptomic signatures of the human adult pituitary gland•CD adenomas overexpress PMAIP1, which encodes the pro-apoptotic protein noxa•Noxa is degraded in CD adenomas to evade apoptosis•Bortezomib proteasomal inhibition stabilizes Noxa and induces apoptosis Asuzu et al. perform single-cell transcriptomic profiling in Cushing’s disease (CD) adenomas and find overexpression and DNA hypomethylation of PMAIP1, which encodes the pro-apoptotic protein noxa. Noxa is degraded by the proteasome. Proteasomal inhibition rescues noxa and induces apoptosis in CD.