Integrated multi-omics profiling of nonfunctioning pituitary adenomas

Area of Science:

• Endocrinology and Molecular Biology
• Genetics and Genomics
• Cancer Research

Background:

• Pituitary adenomas are common tumors, with nonfunctioning pituitary adenomas (NFPAs) comprising a significant subset.
• The molecular mechanisms underlying the pathogenesis of proliferative NFPAs remain incompletely understood.
• Genetic and epigenetic alterations are implicated in tumor development, but their specific roles in NFPAs require further elucidation.

Purpose of the Study:

• To investigate the integrated multi-omics profiles, including copy number variation (CNV), DNA methylation, and gene expression, in proliferative NFPAs.
• To identify molecular alterations and aberrant pathways associated with highly proliferative NFPAs (hpNFPAs).
• To elucidate the molecular basis of hpNFPA development.

Main Methods:

• Analysis of 8 NFPAs, categorized into highly proliferative (Ki-67 ≥ 3) and lowly proliferative (Ki-67 ≤ 1) groups.
• Comprehensive assessment of CNV, DNA methylation (using Illumina HumanMethylation450 BeadChip), and gene expression (using Affymetrix GeneChip PrimeView Human Gene Expression Array).
• Ingenuity Pathway Analysis (IPA) for differentially expressed genes and delineation of protein-protein networks for key genes.

Main Results:

• Aberrant arm-level CNV and dysregulated DNA methylation impacting gene expression were observed in early-occurring hpNFPAs.
• Chromosomal losses correlated with reduced DNA methyltransferase expression, influencing global methylation.
• IPA revealed activated pathways (e.g., PPARα/RXRα, dopamine, cAMP, calcium signaling) and inhibited pathways (e.g., p38 MAPK, ERK5) in hpNFPAs. Key gene networks showed concurrent methylation and expression changes.

Conclusions:

• This study provides a comprehensive multi-omics view of CNV, DNA methylation, and gene expression in NFPAs.
• Pathway and network analyses offer critical insights into the molecular underpinnings of highly proliferative NFPAs.
• The findings contribute to understanding the pathogenesis of pituitary adenomas and may guide future therapeutic strategies.