Insulin signalling-associated cell fate promotes neoplastic invasiveness in non-functioning pituitary gonadotroph adenoma via cis-regulatory elements activation.

Abstract

Background: Non-functioning pituitary gonadotroph adenoma (NFGA) is the most prevalent subtype of pituitary adenomas with a tendency to develop into a refractory invasive type. Currently, effective pharmacotherapy for NFGA remains to be developed due to limited understanding of exact mechanisms of its invasiveness.

Methods: Here, we integrated scRNA-seq and scATAC-seq data from three NFGA patients to investigate the cellular heterogeneity underlying tumour invasion. An independent cohort with 210 patients and three primary cell lines was used to evaluate the association between insulin signalling and NFGA invasiveness.

Results: We suggested that neoplastic cells exhibited five cellular states with epigenetic heterogeneity along three distinct cell fates. Notably, we identified an insulin signalling-associated cell fate as the driver for tumour invasiveness and invasive NFGAs exhibited elevated insulin resistance-related indices. In vitro assays on primary cell lines showed insulin signalling promoted tumour invasion of NFGA. Additionally, based on cis-co-accessible network analysis, we observed that invasive NFGA reconstructed chromatin-chromatin interactions at insulin signalling-associated-SREBF1-linked cis-regulatory elements (CREs) and IGF2BP2-linked CREs, which recruited active transcriptional factors (TFs) for gene expression activation. We further validated the role of IGF2BP2-linked CREs in regulating IGF2BP2 expression and tumour cell invasion.

Conclusions: Our data revealed that cis-regulatory elements activated insulin signalling on invasive cell fate of NFGA and novel therapeutic strategies targeting insulin signalling could be utilised for improving patient outcomes.