Happy 20th anniversary MEN1: from positional cloning to gene function restoration

Major Genetic Motifs in Pituitary Adenomas: A Practical Literature Update

BACKGROUND

The literature includes many studies examining the genetic abnormalities that influence pituitary adenomas (PAs). We aimed to state the collective knowledge on the genetic underpinnings of PAs by organizing, summarizing, and consolidating the literature to serve as a comprehensive review for scientists and clinicians of the most up-to-date information underlying the genetic landscape of PAs.

METHODS

The PubMed and Google Scholar databases were searched using multiple key words and combined Medical Subject Headings terms; only articles published in English between January 2000 and January 2022 were included. Articles in which the focus did not relate to genetics, that included mainly anecdotal evidence, or that were single case studies were eliminated.

RESULTS

PAs are one of the most common intracranial neoplasms. However, the genetic underpinnings for these tumors are not yet fully elucidated. There are several categories of PAs: clinically significant versus not clinically significant, functional versus nonfunctional, and germline-derived versus sporadic origin. Each of these disease subcategories is characterized by unique genetic aberrations. Recently, more genes and other types of genetic aberrations have been identified as possible causes of PAs, such as copy number variations and altered levels of microRNAs.

CONCLUSIONS

This review serves to consolidate and summarize the literature discussing the genetic motifs of PAs to help physicians and scientists deliver patient-centered therapies.

Menin Enhances Androgen Receptor-Independent Proliferation and Migration of Prostate Cancer Cells

The androgen receptor (AR) is an important therapeutic target for treating prostate cancer (PCa). Moreover, there is an increasing need for understanding the AR-independent progression of tumor cells such as neuroendocrine prostate cancer (NEPC). Menin, which is encoded by multiple endocrine neoplasia type 1 (MEN1), serves as a direct link between AR and the mixed-lineage leukemia (MLL) complex in PCa development by activating AR target genes through histone H3 lysine 4 methylation. Although menin is a critical component of AR signaling, its tumorigenic role in AR-independent PCa cells remains unknown. Here, we compared the role of menin in AR-positive and AR-negative PCa cells via RNAi-mediated or pharmacological inhibition of menin. We demonstrated that menin was involved in tumor cell growth and metastasis in PCa cells with low or deficient levels of AR. The inhibition of menin significantly diminished the growth of PCa cells and induced apoptosis, regardless of the presence of AR. Additionally, transcriptome analysis showed that the expression of many metastasis-associated genes was perturbed by menin inhibition in AR-negative DU145 cells. Furthermore, wound-healing assay results showed that menin promoted cell migration in AR-independent cellular contexts. Overall, these findings suggest a critical function of menin in tumorigenesis and provide a rationale for drug development against menin toward targeting high-risk metastatic PCa, especially those independent of AR.

Multiple endocrine neoplasia 1: a broad overview

This review article discusses the diagnoses and treatment of patients with multiple endocrine neoplasia type 1 (MEN 1). The most common tumors associated with MEN 1 are located in the pancreas, pituitary, and parathyroid glands. Less common tumors include neuroendocrine tumors of the lung and thymus, adrenal tumors, and cutaneous lesions. This article describes the diagnosis, clinical manifestations, treatment, and surveillance of tumors associated with patients who are diagnosed with MEN 1.

Germline mutations in MEN1 are associated with the tumorigenesis of pituitary adenoma associated with meningioma

Pituitary adenoma and meningioma are two of the most common benign tumors in the central nervous system. Pituitary adenoma associated with meningioma (PAM) is a rare disease, the tumorigenesis of which remains unclear. Therefore, the aim of the present study was to investigate the tumorigenesis of PAM. A total of 8,197 patients with pituitary adenoma were analyzed. Furthermore, the clinical data of 57 patients with PAM were compared with patients with multiple endocrine neoplasia 1 (MEN-1) syndrome. Whole exome sequencing (WES) was performed on 23 samples from patients with PAM and the germline mutation was verified by Sanger sequencing. The age of tumor penetrance (age of patients at diagnosis) for PAM was significantly higher than that for patients with MEN-1. Compared with MEN-1 patients, there was a significant association between PAM and female sex (P=0.004). Clonal analysis and phylogenetic tree construction suggested that the pituitary adenoma and meningioma in PAM don't originate from a common progenitor. WES revealed that 5/23 PAM samples had the recurrent germline mutation MEN1 c.1523G>A; p.G508D, which may be a genetic risk factor for PAM. Compared with patients with sporadic pituitary adenoma, the difference was statistically significant (P=0.0004). Compared with wild-type MEN1, there was a significant association between the MEN1 mutation and recurrence of pituitary adenoma, young age and larger diameter of the meningioma. The present study indicated that germline mutations in MEN1 may be associated with the tumorigenesis of PAM.

The clinical characteristics and molecular mechanism of pituitary adenoma associated with meningioma

BACKGROUND

Pituitary adenoma and meningioma are the most common benign tumors in the central nervous system. Pituitary adenoma associated with meningioma (PAM) is a rare disease and the clinical features and mechanisms of PAM are unclear.

METHODS

We summarized the clinical data of 57 PAM patients and compared with sporadic pituitary adenoma (SPA) and sporadic meningioma (SM). 5 pituitary adenomas of PAM and 5 SPAs were performed ceRNA microarray. qRT-PCR, Western Blot, siMEN1 and rapamycin inhibition experiment were validated for ceRNA microarray.

RESULTS

Clinical variable analyses revealed that significant correlations between PAM and female sex as well as older age when compared with SPA and significant correlations between PAM and transitional meningioma as well as older age when compared with SM. Additionally, the characteristics of PAM were significantly different for MEN1 patients. Functional experiments showed lower expression of MEN1 can upregulate mTOR signaling, in accordance with the result of ceRNA microarray. Rapamycin treatment promotes apoptosis in primary pituitary adenoma and meningioma cells of PAM.

CONCLUSIONS

MEN1 plays an important role in PAM by upregulating mTOR signaling pathway. Rapamycin represents a potential therapeutic strategy for PAM in the future.