Objectives: Pituitary stem cells play a role in the oncogenesis of human adamantinomatous craniopharyngiomas (aCPs). We hypothesized that crosstalk between the Wnt/b-catenin and Sonic Hedgehog (SHH) pathways, both of which are important in normal pituitary development, would contribute to the pathogenesis of aCPs. Design: To explore the mRNA and protein expression of components of the SHH signaling pathway in aCPs and their relationship with the identification of CTNNB1/b-catenin mutations and patients outcomes. Patients and methods: In 18 aCP samples, CTNNB1 was sequenced, and the mRNA expression levels of SHH pathway members (SHH, PTCH1, SMO, GLI1, GLI2, GLI3, and SUFU) and SMO, GLI1, GLI3, SUFU, b-catenin, and Ki67 proteins were evaluated by quantitative real-time PCR and immunohistochemistry respectively. Anterior normal pituitaries were used as controls. Associations between molecular findings and clinical data were analyzed. Results: The aCPs presented higher mRNA expression of SHH (C400-fold change (FC); P!0.01), GLI1 (C102-FC; P!0.001), and GLI3 (C5.1-FC; P!0.01) than normal anterior pituitaries. Longer disease-free survival was associated with low SMO and SUFU mRNA expression (P!0.01 and PZ0.02 respectively). CTNNB1/b-catenin mutations were found in 47% of the samples. aCPs with identified mutations presented with higher mRNA expression of SMO and GLI1 (C4.3-FC; PZ0.02 and C10.2-FC; PZ0.03 respectively). SMO, GLI1, GLI3, and SUFU staining was found in 85, 67, 93, and 64% of the samples respectively. Strong GLI1 and GLI3 staining was detected in palisade cells, which also labeled Ki67, a marker of cell proliferation. Conclusions: The upregulation of SHH signaling occurs in aCPs. Thus, activation of Wnt/b-catenin and SHH pathways, both of which are important in pituitary embryogenesis, appears to contribute to the pathogenesis of aCP.

Genes involved in formation/development of the adenohypophysis, CTNNB1 gene, and microRNAs might be implicated in the craniopharyngioma pathogenesis. The objective of this study is to perform the molecular analysis of HESX1, PROP1, POU1F1, and CTNNB1 genes and evaluate a panel of miRNA expression in craniopharyngioma. We also verified whether the presence of CTNNB1 mutation is associated with clinical findings and miRNA expression. The study included 16 patients with adamantinomatous craniopharyngioma (nine children and seven adults; eight females and eight males; 6-55 years, median 15.5 years). DNA, RNA, and cDNA were obtained from craniopharyngioma and normal pituitaries. DNA was also extracted from peripheral blood of healthy subjects. All genes were amplified by polymerase chain reaction and direct sequenced. Relative quantification of miRNA expression was calculated using the 2(-ΔΔCt) method. We found no mutations in HESX1, PROP1, and POU1F1 genes and four polymorphisms in PROP1 gene which were in Hardy-Weinberg equilibrium and had similar allelic frequencies in craniopharyngioma and controls. We found seven different mutations in CTNNB1 in eight of 16 patients. Younger patients presented more frequently CTNNB1 mutation than adults. We observed hyperexpression of miR-150 (1.7-fold); no different expression of miR-16-1, miR-21, and miR23a; and an underexpression of miR-141, let-7a, miR-16, miR-449, miR-145, miR-143, miR-23b, miR-15a, and miR-24-2 (ranging from -7.5 to -2.5-fold; p = 0.02) in craniopharyngioma. There was no association between tumor size or the recurrence and the presence of CTNNB1mutations. miR-16 and miR-141 were underexpressed in craniopharyngioma presenting CTNNB1 mutations. miR-23a and miR24-2 were hyperexpressed in patients who underwent only one surgery. Mutations or polymorphisms in pituitary transcription factors are unlikely to contribute to the adamantinomatous craniopharyngioma pathogenesis, differently of CTNNB1 mutations. Our data suggest the potential involvement of the deregulation of miRNA expression in the craniopharyngioma pathogenesis and outcome and also that the miRNA could modulate the Wnt signaling pathway in craniopharyngioma tumorigenesis.

mutations and abnormal β-catenin distribution are associated with the pathogenesis of adamantinomatous craniopharyngioma (aCP). We evaluated the expression of the canonical Wnt pathway components in aCPs and its association with mutations and tumor progression. Tumor samples from 14 aCP patients and normal anterior pituitary samples from eight individuals without pituitary disease were studied. Gene expression of Wnt pathway activator (), inhibitors (, ,, and ), transcriptional activator (), target genes (, , and,), and Wnt modulator () was evaluated by qPCR. β-Catenin, , and expression was determined by immunohistochemistry (IHC). The transcription levels of all genes studied, except , were higher in aCPs as compared to controls and mRNA levels correlated with mutation. mRNA was overexpressed in tumor samples of patients with disease progression in comparison to those with stable disease. β-Catenin was positive and aberrantly distributed in 11 out of 14 tumor samples. Stronger β-catenin immunostaining associated positively with tumor progression. positive staining was found in 10 out of 14 cases, whereas all aCPs were negative for. Wnt pathway genes were overexpressed in aCPs harboring mutations and in patients with progressive disease. Recurrence was associated with stronger staining for β-catenin. These data suggest that Wnt pathway activation contributes to the pathogenesis and prognosis of aCPs.

Research from the last 20 years has provided important insights into the molecular pathogenesis of craniopharyngiomas (CPs). Besides the well-known clinical and histological differences between the subtypes of CPs, adamantinomatous (ACP) and papillary (PCP) craniopharyngiomas, other molecular differences have been identified, further elucidating pathways related to the origin and development of such tumors. The present minireview assesses current knowledge on embryogenesis and the genetic, epigenetic, transcriptomic, and signaling pathways involved in the ACP and PCP subtypes, revealing the similarities and differences in their profiles. ACP and PCP subtypes can be identified by the presence of mutations in CTNNB1 and BRAF genes, with prevalence around 60% and 90%, respectively. Therefore, β-catenin accumulates in the nucleus-cytoplasm of cell clusters in ACPs and, in PCPs, cell immunostaining with specific antibody against the V600E-mutated protein can be seen. Distinct patterns of DNA methylation further differentiate ACPs and PCPs. In addition, research on genetic and epigenetic changes and tumor microenvironment specificities have further clarified the development and progression of the disease. No relevant transcriptional differences in ACPs have emerged between children and adults. In conclusion, ACPs and PCPs present diverse genetic signatures and each subtype is associated with specific signaling pathways. A better understanding of the pathways related to the growth of such tumors is paramount for the development of novel targeted therapeutic agents.