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// Manuela Mancini 1 , Simona Soverini 1 , Gabriele Gugliotta 1 , Maria Alessandra Santucci 1 , Gianantonio Rosti 1 , Michele Cavo 1 , Giovanni Martinelli 1 and Fausto Castagnetti 1 1 Department of Experimental Diagnostic and Specialty Medicine, DIMES–Institute of Hematology “L. and A. Seragnoli”, University of Bologna Medical School, Bologna, Italy Correspondence to: Manuela Mancini, email: mancini_manu@yahoo.com Keywords: chibby1, s-catenin, ER stress, autophagy, BCR-ABL1 Received: March 31, 2017 Accepted: August 04, 2017 Published: September 22, 2017 ABSTRACT Chibby 1 (CBY1) is a small and evolutionarily conserved protein, which act as β-catenin antagonist. CBY1 is encoded by C22orf2 (22q13.1) Its antagonistic function on β-catenin involves the direct interaction with: The C-terminal activation domain of β-catenin, which hinders β-catenin binding with Tcf/Lef transcription factors hence repressing β-catenin transcriptional activation. 14-3-3 scaffolding proteins (σ or ξ), which drive CBY1 nuclear export into a stable tripartite complex with β-catenin. The relative proximity of C22orf2 gene encoding for CBY1 to the BCR breakpoint on chromosome 22q11, whose translocation and rearrangement with the c-ABL is the causative event of chronic myeloid leukemia (CML), suggested that gene haploinsufficiency may play a role in the disease pathogenesis and progression. We found CBY1 down-modulation associated with the BCR-ABL1 , promoted by transcriptional mechanisms (promoter hyper-methylation) and post-transcriptional events, addressing the protein towards proteasome-dependent degradation through SUMOylation. CBY1 reduced expression in clonal progenitors and, more importantly, in leukemic stem cells (LSC), is contingent upon the tyrosine kinase (TK) activity of BCR-ABL1 fusion protein. Accordingly, its induction by Imatinib (IM) and second generation TK inhibitors contributes to β-catenin inactivation through multiple events encompassing the activation of endoplasmic reticulum (ER) stress-associated unfolded protein response (UPR) and autophagy, eventually leading to apoptotic death. These findings support the advantage of combined regimens including drugs targeting DNA epigenetics and/or proteasome to eradicate the BCR-ABL1+ hematopoiesis.

BACKGROUND: The aberrant activation of Wnt signalling pathway may be a common denominator for the development of thyroid tumorigenesis. It was announced that the loss of E-cadherin rather than β-catenin mutation represents a crucial event in determining the degree of differentiation of thyroid carcinomas.AIM: The aim of the study was to evaluate the expression of E-cadherin and β-catenin in the thyroid cancer tissue and to correlate these data with some histological and clinical parameters of the tumours.MATERIAL AND METHODS: We investigated 112 patients, having thyroid tumours – papillary, follicular, anaplastic and oncocytic carcinomas immunohistochemically with antibodies against E-cadherin and β-catenin. Survival analyses were done.RESULTS: E-cadherin expression was focally retained in the tumour cell membranes and the tumour cell cytoplasm of the papillary, follicular and oncocytic thyroid cancers, weather in anaplastic cancers it was almost lost (p = 0.0042, and р = 0.019, respectively, Fisher's Exact Test). The expression of β-catenin in tumour cytoplasm and membrane in papillary cancers was higher as compared to that in the other tumours (p = 0.111, and р = 0.0104, respectively).CONCLUSION: Not surprisingly, the presence of aberrant expression of E-cadherin and β-catenin in thyroid cancer has been associated with better patients' prognosis and better differentiated tumour histology.

Primary progressive multiple sclerosis (PP-MS) is a less common progressive form of MS in approximately 10% of patients that manifest increasingly neurological disability from disease onset. To date, there are no approved treatments for the progressive stage. Therefore, identifying new therapeutic targets could open a new opportunity for PP-MS management. Several lines of evidence suggest the critical role of the Wnt/β-catenin pathway in immune-mediated diseases, like MS. This study was aimed to investigate whether aberrant expression of β-catenin is involved in PP-MS progression. By western blot analysis the expression of β-catenin was evaluated in CD4+ cells purified from peripheral blood of PP-MS patients. Specifically, nuclear expression of β-catenin was detected in CD4+ T cells purified from peripheral blood lymphocytes of PP-MS, and not of other neuromuscular diseases. In addition, no relevant expression of Wnt-1 was found in PP-MS patients, suggesting that the increase in nuclear β-catenin expression in these cells could be independent from canonical Wnt pathway. Taken together, our observations demonstrate that the deregulation of the β-catenin expression is involved in CD4+ T cells of PP-MS patients. Therefore, inhibitors of β-catenin pathway could be proposed as a promising candidate strategy for PP-MS cure.

Hepatocellular carcinoma (HCC) is one of the most common cancers in the world, and represents the second most frequently cancer and third most common cause of death from cancer worldwide. At advanced stage, HCC is a highly aggressive tumor with a poor prognosis and with very limited response to common therapies. Therefore, there is still the need for new effective and well-tolerated therapeutic strategies. Molecular-targeted therapies hold promise for HCC treatment. One promising molecular target is the multifunctional serine/threonine kinase glycogen synthase kinase 3 (GSK-3). The roles of GSK-3β in HCC remain controversial, several studies suggested a possible role of GSK-3β as a tumor suppressor gene in HCC, whereas, other studies indicate that GSK-3β is a potential therapeutic target for this neoplasia. In this review, we will focus on the different roles that GSK-3 plays in HCC and its interaction with signaling pathways implicated in the pathogenesis of HCC, such as Insulin-like Growth Factor (IGF), Notch, Wnt/β-catenin, Hedgehog (HH), and TGF-β pathways. In addition, the pivotal roles of GSK3 in epithelial-mesenchymal transition (EMT), invasion and metastasis will be also discussed.

The activation of oncogenic Wnt/β-catenin pathway in melanoma contributes to a lack of T-cell infiltration. Whether baseline β-catenin expression in the context of tumour-infiltrating lymphocytes (TILs) and programmed death ligand-1 (PD-L1) overexpression correlates with prognosis of metastatic melanoma patients (MMPs) treated with mitogen-activated protein kinase, MAPK inhibitor (MAPKi) monotherapy, however, has not been fully clarified.Sixty-four pre-treatment formalin-fixed and paraffin embedded melanoma samples from MMP treated with a BRAF inhibitor (n = 39) or BRAF and MEK inhibitors (n = 25) were assessed for presence of β-catenin, PD-L1, cluster of differentiation (CD)8, CD103 and forkhead box protein P3 (FOXP3) expression by immunohistochemistry, and results were correlated with clinical outcome. Quantitative assessment of mRNA transcripts associated with Wnt/β-catenin pathway and immune response was performed in 51 patients.We found an inverse correlation between tumoural β-catenin expression and the level of CD8, CD103 or forkhead box protein P3 (FOXP3) positivity in the tumour microenvironment (TME). By multivariate analysis, PD-L15% (odds ratio, OR 0.12, 95% confidence interval, CI 0.03-0.53, p = 0.005) and the presence of CD8+ T cells (OR 18.27, 95%CI 2.54-131.52, p = 0.004) were significantly associated with a higher probability of response to MAPKi monotherapy. Responding patients showed a significantly increased expression of mRNA transcripts associated with adaptive immunity and antigen presentation. By multivariate analysis, progression-free survival (PFS) (hazards ratio (HR) = 0.25 95%CI 0.10-0.61, p = 0.002) and overall survival (OS) (HR = 0.24 95%CI 0.09-0.67, p = 0.006) were longer in patients with high density of CD8+ T cells and β-catenin10% than those without CD8+ T cells infiltration and β-catenin ≥10%.Our findings provide evidence that in the context of MAPKi monotherapy, immune subsets in the (TME) and gene signature predict prognosis in MMPs.

Aims Glycogen synthase kinase-3 beta (GSK-3β) is a serine/threonine kinase involved in glycogen metabolism, cell cycle progression, differentiation, embryogenesis, migration, metabolism, survival and cellular senescence. Its main biological function is to inhibit β-catenin by sequestration and promotion of its proteasomal degradation in the Wnt canonical pathway; however, GSK-3β interacts with multiple signalling pathways, and aberrant expression of the enzyme was reported in many solid neoplasms. This study aimed to investigate the biological relevance of GSK-3β in classical Hodgkin lymphomas (cHL). Methods and results We analysed the functional status of GSK-3β enzyme in cHL by using antibodies raised against fixation-resistant epitopes of phospho Y216 GSK-3β (active form), phospho S9 GSK-3β (inactive form) and β-catenin protein. We first detected the pY216 GSK-3β active form of the enzyme in 100 of 100 (100%) of the cases, and in line with the latter expression profile, the β-catenin protein was found in only 12 of 100 (12%) of the samples. As reported previously in bladder cancer, pancreatic adenocarcinoma and chronic lymphocytic leukaemia, we showed an aberrant nuclear localization in the neoplastic clone of active pY216 GSK-3β in 78 of 100 (78%) of cHL cases. Conclusions We demonstrated the activation of GSK-3β in cHL resulting in inhibition of the Wnt/β-catenin signal cascade and the aberrant accumulation of its activated form in nuclei of Hodgkin Reed-Sternberg and Hodgkin cells. These findings may be relevant for future clinical studies, identifying GSK-3β as a potential therapeutic target for cHL.

Desmoid fibromatosis is a locally aggressive myofibroblastic neoplasm that may occur at abdominal, intra-abdominal and extra-abdominal locations. Most cases occur sporadically; however, a minority of cases is associated with familial adenomatous polyposis (Gardner syndrome). Morphologically, desmoid fibromatosis is an infiltrative, bland spindle cell proliferation set in a collagenized stroma. The characteristic immunophenotype is represented by expression of smooth muscle actin and β-catenin. Genetically, two distinct molecular events involve two different proteins, both members of the WNT signalling pathway. In fact, familial desmoids display germline inactivating mutations in the adenomatous polyposis coli ( APC ) gene, whereas most sporadic desmoids harbour activating mutations in exon 3 of the CTNNB1 gene that encodes β-catenin. As desmoid fibromatosis represents a major therapeutic challenge, further clarification of the molecular oncogenesis of this disease may offer a rationale to develop innovative therapeutic approaches.

Wnt/β-catenin signaling plays an important role in the regulation of embryonic development and tumorigenesis. Since its deregulation results in severe human diseases, especially cancer, the Wnt signaling pathway constitutes a promising platform for pharmacological targeting of cancer. In this study we synthesized a series of imidazo[1,2-a]pyrimidines and imidazo[1,2-a]pyridines and identified some derivatives that were able to inhibit the Wnt/β-catenin signaling pathway in a luciferase reporter assay and cell proliferation in selected cancer cell lines, endowed with APC or β-catenin gene mutations. The most active compounds significantly downregulate the expression of Wnt target genes such as c-myc and cyclin D1. Further studies indicated that these compounds function independently of GSK-3β activity. More importantly, in vivo experiments, carried out on a Wnt-reporter zebrafish model indicate, in particular for compounds 4c and 4i as the most active compounds, an activity comparable to that of the reference compound IWR1, suggesting their potential use not only as small molecule inhibitors of the Wnt/β-catenin signal in Wnt driven cancers, but also in other Wnt-related diseases.