CBX4-dependent regulation of HDAC3 nuclear translocation reduces Bmp2-induced osteoblastic differentiation and calcification in adamantinomatous craniopharyngioma

Background Calcification of adamantinomatous craniopharyngioma (ACP) often causes problems with tumor resection, leading to a high incidence of deadly complications and tumor recurrence. Histone acetyltransferase (HAT) and histone deacetylase (HDAC) are 2 key enzymes that regulate histone acetylation and play important roles in tumor development. However, the roles of HAT and HDAC in the calcification and osteoblastic differentiation of ACP are not known. Methods In this study, primary cells were isolated from ACP tissues, and calcification was induced with bone morphogenetic protein 2 (Bmp2). HDAC3 expression was assessed in 12 tissue samples by Western blotting and immunohistochemistry. ACP calcification was assessed by Alizarin red staining. A luciferase reporter assay was performed to examine the interaction between miR-181b and the 3’-untranslated region of the polycomb chromobox 4 (CBX4) gene. Results Our results showed that the expression of HDAC3 was increased in the calcified ACP samples, but inhibition of HDAC3 promoted ACP cell calcification and osteoblastic differentiation. Mechanistically, HDAC3 nuclear translocation was suppressed by Bmp2, leading to Runx2 protein expression and Osterix, osteocalcin (OCN), osteopontin (OPN), and alkaline phosphatase (ALP) mRNA expression. In addition, this process was suppressed by CBX4, which stabilized the nuclear localization of HDAC3. miR-181b, the expression of which was increased in Bmp2-induced ACP cells, directly targeted and decreased CBX4 expression and inhibited the nuclear localization of HDAC3. Conclusions Our results demonstrate that Bmp2 increases miR-181b levels to directly target and inhibit CBX4 expression, leading to a reduction in the CBX4-dependent regulation of HDAC3 nuclear translocation, which results in Runx2 activation/osteoblastic differentiation and calcium deposition in ACP. Further studies targeting these cascades may contribute to therapeutic interventions used for recurrent ACP.

Adamantinomatous Craniopharyngioma Cyst Fluid can Trigger Inflammatory Activation of Microglia to Damage the Hypothalamic Neurons by Inducing the Production of β-Amyloid

Introduction: The mechanism by which adamantinomatous craniopharyngioma (ACP) damages the hypothalamus is still unclear. Cyst fluid rich in lipids and inflammatory factors is a characteristic pathological manifestation of ACP and may play a very important role in hypothalamic injury caused by tumors. Objective: To construct a reliable animal model of ACP cyst fluid-induced hypothalamic injury and explore the specific mechanism of hypothalamic injury caused by cyst fluid. Methods: An animal model was establish by injecting human ACP cyst fluid into the bilateral hypothalamus of mice . ScRNA-seq was performed on the mice hypothalamus and on an ACP sample to obtain a complete gene expression profile for analysis. Data verification was performed through pathological means. Results: ACP cystic fluid caused growth retardation and an increased obesity index in mice, affected the expression of the Npy, Fgfr2, Rnpc3, Sst, and Pcsk1n genes that regulate growth and energy metabolism in hypothalamic neurons, and enhanced the cellular interaction of Agrp-Mc3r. ACP cystic fluid significantly caused inflammatory activation of hypothalamic microglia. The cellular interaction of CD74-APP is significantly strengthened between inflammatory-activated microglia and hypothalamic neurons. Beta-amyloid, a marker of neurodegenerative diseases, was deposited in the ACP tumor tissues and in the hypothalamus of mice injected with ACP cyst fluid. Conclusion: In this study, a novel animal model of ACP cystic fluid-hypothalamic injury was established. For the first time, it was found that ACP cystic fluid can trigger inflammatory activation of microglia to damage the hypothalamus, which may be related to the upregulation of the CD74-APP interaction and deposition of β-amyloid, implying that there may be a similar mechanism between ACP cystic fluid damage to the hypothalamus and neurodegenerative diseases.

Expression of Insulin-like Growth Factor Type 1 Receptor is Linked to Inflammation in Adamantinomatous Craniopharyngioma

Introduction Insulin-like growth factor type 1 receptor (IGF1R) is overexpressed in various malignant tumors, which relates to their transformation and recurrence. Craniopharyngioma is a benign tumor with malignant results, often accompanied by a severe inflammatory reaction. However, the relationship between IGF1R expression and the inflammatory response of craniopharyngioma is unclear. Methods We enrolled 85 patients with adamantinomatous craniopharyngioma (ACP) in a study to explore the relationship between IGF1R expression and clinical features of this disease. Results Patients in the IGF1R high expression group had a significantly higher incidence of hypopituitarism, higher recurrence rate and lower progression-free survival. Beta-catenin can further regulate expression of the stem cell marker, CD44, by regulating IGF1R. Using immunofluorescence, we found that tumor stem cell–like cells did not express phosphorylated (p)-ERK, although p-ERK activation was evident in the surrounding cells. Picropodophyllin, a specific inhibitor of IGF1R, increased the expression of p-ERK protein, and decreased the transcription level of interleukin-6. Conclusions High expression of IGF1R might promote inflammation of ACP, which might be an unfavorable factor for pituitary function and prognosis. The high expression of IGF1R in tumor cell stem-like cells might inhibit the expression of p-ERK and promote the generation of inflammatory factors. Insulin-like growth factor type 1 receptor plays a stemness maintenance role in ACP and regulates the production of inflammatory factors through a p-ERK pathway, which suggests that targeting IGF1R and p-ERK might provide a new direction for alleviating tumor inflammation.

A Novel Immune Classification for Predicting Immunotherapy Responsiveness in Patients With Adamantinomatous Craniopharyngioma

Adamantinomatous craniopharyngioma (ACP) is the most common tumor of the sellar region in children. The aggressive behavior of ACP challenges the treatment for it. However, immunotherapy is rarely studied in ACP. In this research, we performed unsupervised cluster analysis on the 725 immune-related genes and arrays of 39 patients with ACP patients in GSE60815 and GSE94349 databases. Two novel immune subtypes were identified, namely immune resistance (IR) subtype and immunogenic (IG) subtype. Interestingly, we found that the ACPs with IG subtype (34.78%, 8/23) were more likely to respond to immunotherapy than the ACPs with IR subtype (6.25%, 1/16) via tumor immune dysfunction and exclusion (TIDE) method. Simultaneously, the enrichment analysis indicated that the differentially expressed genes (DEGs) (p < 0.01, FDR < 0.01) of the IG subtype were chiefly involved in inflammatory and immune responses. However, the DEGs of the IR subtype were mainly involved in RNA processing. Next, immune infiltration analysis revealed a higher proportion of M2 macrophage in the IG subtype than that in the IR subtype. Compared with the IR subtype, the expression levels of immune checkpoint molecules (PD1, PDL1, PDL2, TIM3, CTLA4, Galectin9, LAG3, and CD86) were significantly upregulated in the IG subtype. The ssGSEA results demonstrated that the biofunction of carcinogenesis in the IG subtype was significantly enriched, such as lymphocyte infiltration, mesenchymal phenotype, stemness maintenance, and tumorigenic cytokines, compared with the IR subtype. Finally, a WDR89 (the DEG between IG and IR subtype)-based nomogram model was constructed to predict the immune classification of ACPs with excellent performance. This predictive model provided a reliable classification assessment tool for clinicians and aids treatment decision-making in the clinic.

Diffuse Necrotizing Myelitis following Intracystic Bleomycin Chemotherapy for Craniopharyngioma

A child with recurrent adamantinomatous craniopharyngioma was treated with surgery and radiosurgery followed by 12 cycles of intracystic bleomycin injections. One month after treatment, he developed progressive lower extremity paresthesia, pain, wide-based gait, and urinary incontinence. MR imaging showed extensive T2 hyperintensity, enlargement, and enhancement extending from the medulla to the lower thoracic spinal cord. Spinal cord biopsy showed necrotizing myelitis. To our knowledge, this is the first histologically proven case of bleomycin spinal cord neurotoxicity.

PATH-38. APC MUTATION AS A DRIVER ONCOGENE IN NON-CTNNB1 MUTANT ADAMANTINOMATOUS CRANIOPHARYNGIOMAS

Craniopharyngiomas arise from the embryonic remnants of Rathke’s pouch in the craniopharyngeal duct. Their invasive capacity and geographic proximity to the optic apparatus, pituitary gland and stalk, third ventricle, and the hypothalamus can cause progressive visual, hormonal, and neurological deficits and transform these lesions into behaviorally malignant tumors. The classic subtypes of craniopharyngiomas, adamantinomatous and papillary, have conventionally been approached similarly in regards to therapeutic strategies. However, recent exome sequencing studies have revealed mutually exclusive pathways for their genetic origins. Recurrent mutations in BRAF (V600E), a regulator of MAP kinase/ERK signaling pathway have been observed in 95% of papillary craniopharyngiomas and may be amenable to targeted therapies with BRAF inhibitors. However, CTNNB1 mutations are observed in only 75%–96% of adamantinomatous craniopharyngiomas, revealing a gap in the classic genetic-histological correlation. We describe a 74-year-old male who underwent resection of a craniopharyngioma with suprasellar and third ventricular involvement. The pathology demonstrated adamantinomatous craniopharyngioma with aberrant nuclear beta-catenin activity on immunohistochemistry. Whole-exome sequencing, performed in accordance with an institutional review board-approved protocol on the tumor and blood, revealed wildtype CTNNB1 but notably two somatic stop-codon mutations in APC (rs786201856:c.C793T:p.R265X and rs587779780:c.1159T:p.R387X), considered pathogenic variants in other reported cancer types. Loss of APC leads to constitutive activation of the Wnt signaling pathway, similar to the observed downstream effects of activating CTNNB1 mutations in adamantinomatous craniopharyngioma. Our case suggests that craniopharyngiomas may arise from somatic loss of APC, which previously was only described in a handful of individuals with familial adenomatous polyposis, harboring germline APC mutations. This report adds new insight into the pathogenesis of adamantinomatous craniopharyngiomas, particularly those that are otherwise wildtype for CTNNB1. Based on accumulating evidence, we propose that along with BRAF and CTNNB1, APC should also be routinely checked in cranipharyngiomas, especially if the former two have been negative.

In-depth proteomic profiling captures subtype-specific features of craniopharyngiomas

Craniopharyngiomas are rare epithelial tumors derived from pituitary gland embryonic tissue. This epithelial tumor can be categorized as an adamantinomatous craniopharyngioma (ACP) or papillary craniopharyngioma (PCP) subtype with histopathological and genetic differences. Genomic and transcriptomic profiles of craniopharyngiomas have been investigated; however, the proteomic profile has yet to be elucidated and added to these profiles. Recent improvements in high-throughput quantitative proteomic approaches have introduced new opportunities for a better understanding of these diseases and the efficient discovery of biomarkers. We aimed to confirm subtype-associated proteomic changes between ACP and PCP specimens. We performed a system-level proteomic study using an integrated approach that combines mass spectrometry-based quantitative proteomic, statistical, and bioinformatics analyses. The bioinformatics analysis showed that differentially expressed proteins between ACP and PCP were significantly involved in mitochondrial organization, fatty acid metabolic processes, exocytosis, the inflammatory response, the cell cycle, RNA splicing, cell migration, and neuron development. Furthermore, using network analysis, we identified hub proteins that were positively correlated with ACP and PCP phenotypes. Our findings improve our understanding of the pathogenesis of craniopharyngiomas and provide novel insights that may ultimately translate to the development of craniopharyngioma subtype-specific therapeutics.

SERPINs in Macrophage May Be Key Inflammation Regulator and Relevant to Poor Prognosis in Adamantinomatous Craniopharyngioma

Craniopharyngioma is one of the most prevalent sellar tumors in children. Though normally, gross resection might be reached, while the prognosis and outcome of the patient is much more worse than any other benign tumor. Inflammation in tumor is of essential in tumor growth and progression. We found that inflammation was relevant to patient outcome and macrophages in adamantinomatous craniopharyngioma were activated in an interesting pattern. We then evaluated immune microenvironment in adamantinomatous craniopharyngioma and intended to screen out potential functional molecules for therapeutic targets and predicting prognosis. The results showed that SERPINs family, especially SERPINE1 and SERPING1 were up-regulated in adamantinomatous craniopharyngioma and might be related to patient outcome in malignant tumor. At the same time, the immune environment of adamantinomatous craniopharyngioma was similar with glioma rather than other benign brain tumors. The study firstly proposes the view that ACP might share the same characteristics with malignant brain tumor, and meanwhile preliminarily demonstrates SERPINs, especially SERPINE1 might also play a critical role in ACP, just like other aggressive cancer.