Genetically engineered mouse models of craniopharyngioma: an opportunity for therapy development and understanding of tumor biology

Senescence- and Immunity-Related Changes in the Central Nervous System: A Comprehensive Review

Senescence is a cellular state characterized by an irreversible halt in the cell cycle, accompanied by alterations in cell morphology, function, and secretion. Senescent cells release a plethora of inflammatory and growth factors, extracellular matrix proteins, and other bioactive substances, collectively known as the senescence-associated secretory phenotype (SASP). These excreted substances serve as crucial mediators of senescent tissues, while the secretion of SASP by senescent neurons and glial cells in the central nervous system modulates the activity of immune cells. Senescent immune cells also influence the physiological activities of various cells in the central nervous system. Further, the interaction between cellular senescence and immune regulation collectively affects the physiological and pathological processes of the central nervous system. Herein, we explore the role of senescence in the physiological and pathological processes underlying embryonic development, aging, degeneration, and injury of the central nervous system, through the immune response. Further, we elucidate the role of senescence in the physiological and pathological processes of the central nervous system, proposing a new theoretical foundation for treating central nervous system diseases.

Genomic drivers in craniopharyngiomas: Analysis of the AACR project GENIE database

PURPOSE

Craniopharyngiomas are rare tumors originating in the sellar region, with limited information on their somatic mutational landscape. In this study, we utilized a publicly available genomic database to profile the somatic mutational landscape of craniopharyngioma patients and interrogate differences based on histologic subtype.

METHODS

We utilized the American Association for Cancer Research (AACR) Project Genomics Evidence Neoplasia Information Exchange (GENIE)® database accessed from cBioPortal (v13.1-public) to query all patients with craniopharyngiomas.

RESULTS

Of the 336 patients with sellar tumors, 51 (15.2%) had craniopharyngiomas. Of these 51 patients, 42 (82.4%) were adamantinomatous subtype and 9 (17.6%) were papillary subtype. In this cohort, 32 (62.7%) patients were pediatric, while 19 (37.3%) were adult. The top mutations in the cohort were: CTNNB1 (n = 37; 73%), BRAF (n = 7; 14%), ARID1B (n = 5; 10%), KMT2D (n = 4; 8%), FANCA (n = 4; 8%), ATM (n = 4; 8%), and TERT (n = 3; 8%). Of the 37 patients with CTNNB1 mutations, 8 (21.6%) had S33X, 9 (24.3%) had S37X, 7 (18.9%) had T41X, and 5 (13.5%) had D32X. In this cohort, CTNNB1 mutations tended to co-occur with ATM (n = 4; 10.8%), KMT2C (n = 4; 10.8%), TERT (n = 3; 8.1%), BLM (n = 3; 8.1%), and ERBB2/3 (n = 3; 8.1%), suggesting CTNNB1 mutations tended to co-occur with mutations in genes important in cell growth and survival, chromatin accessibility, and DNA damage response pathways.

CONCLUSIONS

CTNNB1 mutations account for a large proportion of somatic mutations in craniopharyngiomas. Identification of specific point mutations and secondary drivers may advance development of novel craniopharyngioma preclinical models for targeted therapy testing.

Socio-behavioral dysfunction in disorders of hypothalamic-pituitary involvement: The potential role of disease-induced oxytocin and vasopressin signaling deficits

Disorders involving hypothalamic and pituitary (HPIT) structures-including craniopharyngioma, Langerhans cell histiocytosis, and intracranial germ cell tumors-can disrupt brain and endocrine function. An area of emerging clinical concern in patients with these disorders is the co-occurring socio-behavioral dysfunction that persists after standard hormone replacement therapy. Although the two neuropeptides most implicated in mammalian social functioning (oxytocin and arginine vasopressin) are of hypothalamic origin, little is known about how disease-induced damage to HPIT structures may disrupt neuropeptide signaling and, in turn, impact patients' socio-behavioral functioning. Here we provide a clinical primer on disorders of HPIT involvement and a review of neuropeptide signaling and socio-behavioral functioning in relevant animal models and patient populations. This collective evidence suggests that neuropeptide signaling disruptions contribute to socio-behavioral deficits experienced by patients with disorders of HPIT involvement. A better understanding of the biological underpinnings of patients' socio-behavioral symptoms is now needed to enable the development of the first targeted pharmacological strategies by which to manage patients' socio-behavioral dysfunction.

The Challenging Management of Craniopharyngiomas in Adults: Time for a Reappraisal?

Simple Summary

Craniopharyngiomas (CPs) currently represent one of the most challenging diseases to deal with in the group of skull base tumors. Due to their location near, within, or surrounding the pituitary gland and stalk, CPs can be revealed by pituitary tumor syndrome and/or symptoms of hormonal deficiencies. Furthermore, surgery, which represents the first-line therapy, almost always results in hypopituitarism, diabetes insipidus and, in the case of hypothalamic involvement by the tumor, the occurrence of hypothalamic syndrome. The latter is characterized by intractable weight gain associated with severe morbid obesity, memory impairment, attention deficit, reduced impulse control and, eventually, increased risk of cardiovascular and metabolic disorders. Recent progress made in the understanding of the molecular pathways involved in CPs tumorigenesis paves the way for promising alternative therapeutic approaches and diagnostic procedures. Taken together, they lay the groundwork for new paradigms in the management of CPs in adults.

Abstract

Craniopharyngiomas (CPs) are rare tumors of the skull base, developing near the pituitary gland and hypothalamus and responsible for severe hormonal deficiencies and an overall increase in mortality rate. While surgery and radiotherapy represent the recommended first-line therapies for CPs, a new paradigm for treatment is currently emerging, as a consequence of accumulated knowledge concerning the molecular mechanisms involved in tumor growth, paving the way for anticipated use of targeted therapies. Significant clinical and basic research conducted in the field of CPs will undoubtedly constitute a real step forward for a better understanding of the behavior of these tumors and prevent associated complications. In this review, our aim is to summarize the multiple steps in the management of CPs in adults and emphasize the most recent studies that will contribute to advancing the diagnostic and therapeutic algorithms.

Adamantinomatous craniopharyngioma as a model to understand paracrine and senescence-induced tumourigenesis

Cellular senescence is a process that can prevent tumour development in a cell autonomous manner by imposing a stable cell cycle arrest after oncogene activation. Paradoxically, senescence can also promote tumour growth cell non-autonomously by creating a permissive tumour microenvironment that fuels tumour initiation, progression to malignancy and metastasis. In a pituitary tumour known as adamantinomatous craniopharyngioma (ACP), cells that carry oncogenic β-catenin mutations and overactivate the WNT signalling pathway form cell clusters that become senescent and activate a senescence-associated secretory phenotype (SASP). Research in mouse models of ACP has provided insights into the function of the senescent cell clusters and revealed a critical role for SASP-mediated activities in paracrine tumour initiation. In this review, we first discuss this research on ACP and subsequently explore the theme of paracrine tumourigenesis in other tumour models available in the literature. Evidence is accumulating supporting the notion that paracrine signalling brought about by senescent cells may underlie tumourigenesis across different tumours and cancer models.

Cell senescence in neuropathology: A focus on neurodegeneration and tumours

The study of cell senescence is a burgeoning field. Senescent cells can modify the cellular microenvironment through the secretion of a plethora of biologically active products referred to as the senescence-associated secretory phenotype (SASP). The consequences of these paracrine signals can be either beneficial for tissue homeostasis, if senescent cells are properly cleared and SASP activation is transient, or result in organ dysfunction, when senescent cells accumulate within the tissues and SASP activation is persistent. Several studies have provided evidence for the role of senescence and SASP in promoting age-related diseases or driving organismal ageing. The hype about senescence has been further amplified by the fact that a group of drugs, named senolytics, have been used to successfully ameliorate the burden of age-related diseases and increase health and life span in mice. Ablation of senescent cells in the brain prevents disease progression and improves cognition in murine models of neurodegenerative conditions. The role of senescence in cancer has been more thoroughly investigated, and it is now accepted that senescence is a double-edged sword that can paradoxically prevent or promote tumourigenesis in a context-dependent manner. In addition, senescence induction followed by senolytic treatment is starting to emerge as a novel therapeutic avenue that could improve current anti-cancer therapies and reduce tumour recurrence. In this review, we discuss recent findings supporting the role of cell senescence in the pathogenesis of neurodegenerative diseases and in brain tumours. A better understanding of senescence is likely to result in the development of novel and efficacious anti-senescence therapies against these brain pathologies.

Identification of tumor stem-like cells in admanatimomatous craniopharyngioma and determination of these cells' pathological significance

OBJECTIVE

Nuclear β-catenin, a hallmark of active canonical Wnt signaling, can be histologically detected in a subset of cells and cell clusters in up to 94% of adamantinomatous craniopharyngioma (ACP) samples. However, it is unclear whether nuclear β-catenin-containing cells within human ACPs possess the characteristics of tumor stem cells, and it is unknown what role these cells have in ACP.

METHODS

Primary ACP cells were cultured from 12 human ACP samples. Adamantinomatous CP stem cell-like cells (CSLCs) showing CD44 positivity were isolated from the cultured primary ACP cells by performing magnetic-activated cell sorting. The tumor sphere formation, cell cycle distribution, stemness marker expression, and multidifferentiation potential of the CD44- cells and the CSLCs were analyzed.

RESULTS

Compared with the CD44- cells, the cultured human CSLCs formed tumor spheres and expressed CD44 and CD133; moreover, these cells demonstrated nuclear translocation of β-catenin. In addition, the CSLCs demonstrated osteogenic and adipogenic differentiation capacities compared with the CD44- cells. The CSLCs also displayed the capacity for tumor initiation in human-mouse xenografts.

CONCLUSIONS

These results indicate that CSLCs play an important role in ACP development, calcification, and cystic degeneration.

The Inflammatory Milieu of Adamantinomatous Craniopharyngioma and Its Implications for Treatment

Pediatric Adamantinomatous Craniopharyngiomas (ACPs) are histologically benign brain tumors that often follow an aggressive clinical course. Their suprasellar location leaves them in close proximity to critical neurological and vascular structures and often results in significant neuroendocrine morbidity. Current treatment paradigms, involving surgical resection and radiotherapy, confer significant morbidity to patients and there is an obvious need to discover effective and safe alternative treatments. Recent years have witnessed significant efforts to fully detail the genomic, transcriptomic and proteomic make-up of these tumors, in an attempt to identify potential therapeutic targets. These studies have resulted in ever mounting evidence that inflammatory processes and the immune response play a critical role in the pathogenesis of both the solid and cystic portion of ACPs. Several inflammatory and immune markers have been identified in both the cyst fluid and solid tumor tissue of ACP. Due to the existence of effective agents that target them, IL-6 and immune checkpoint inhibitors seem to present the most likely immediate candidates for clinical trials of targeted immune-related therapy in ACP. If effective, such agents may result in a paradigm shift in treatment that ultimately reduces morbidity and results in better outcomes for our patients.

Nonproliferative and Proliferative Lesions of the Rat and Mouse Endocrine System

The INHAND (International Harmonization of Nomenclature and Diagnostic Criteria for Lesions in Rats and Mice) Project (www.toxpath.org/inhand.asp) is a joint initiative among the Societies of Toxicological Pathology from Europe (ESTP), Great Britain (BSTP), Japan (JSTP) and North America (STP) to develop an internationally accepted nomenclature for proliferative and nonproliferative lesions in laboratory animals. The purpose of this publication is to provide a standardized nomenclature for classifying microscopic lesions observed in the endocrine organs (pituitary gland, pineal gland, thyroid gland, parathyroid glands, adrenal glands and pancreatic islets) of laboratory rats and mice, with color photomicrographs illustrating examples of the lesions. The standardized nomenclature presented in this document is also available electronically on the internet (http://www.goreni.org/). Sources of material included histopathology databases from government, academia, and industrial laboratories throughout the world. Content includes spontaneous and aging lesions as well as lesions induced by exposure to test materials. A widely accepted and utilized international harmonization of nomenclature for endocrine lesions in laboratory animals will decrease confusion among regulatory and scientific research organizations in different countries and provide a common language to increase and enrich international exchanges of information among toxicologists and pathologists.

Tumour compartment transcriptomics demonstrates the activation of inflammatory and odontogenic programmes in human adamantinomatous craniopharyngioma and identifies the MAPK/ERK pathway as a novel therapeutic target

Adamantinomatous craniopharyngiomas (ACPs) are clinically challenging tumours, the majority of which have activating mutations in CTNNB1. They are histologically complex, showing cystic and solid components, the latter comprised of different morphological cell types (e.g. β-catenin-accumulating cluster cells and palisading epithelium), surrounded by a florid glial reaction with immune cells. Here, we have carried out RNA sequencing on 18 ACP samples and integrated these data with an existing ACP transcriptomic dataset. No studies so far have examined the patterns of gene expression within the different cellular compartments of the tumour. To achieve this goal, we have combined laser capture microdissection with computational analyses to reveal groups of genes that are associated with either epithelial tumour cells (clusters and palisading epithelium), glial tissue or immune infiltrate. We use these human ACP molecular signatures and RNA-Seq data from two ACP mouse models to reveal that cell clusters are molecularly analogous to the enamel knot, a critical signalling centre controlling normal tooth morphogenesis. Supporting this finding, we show that human cluster cells express high levels of several members of the FGF, TGFB and BMP families of secreted factors, which signal to neighbouring cells as evidenced by immunostaining against the phosphorylated proteins pERK1/2, pSMAD3 and pSMAD1/5/9 in both human and mouse ACP. We reveal that inhibiting the MAPK/ERK pathway with trametinib, a clinically approved MEK inhibitor, results in reduced proliferation and increased apoptosis in explant cultures of human and mouse ACP. Finally, we analyse a prominent molecular signature in the glial reactive tissue to characterise the inflammatory microenvironment and uncover the activation of inflammasomes in human ACP. We validate these results by immunostaining against immune cell markers, cytokine ELISA and proteome analysis in both solid tumour and cystic fluid from ACP patients. Our data support a new molecular paradigm for understanding ACP tumorigenesis as an aberrant mimic of natural tooth development and opens new therapeutic opportunities by revealing the activation of the MAPK/ERK and inflammasome pathways in human ACP.