Role of β-catenin expression in paediatric mesenchymal lesions: a tissue microarray-based immunohistochemical study

P4HA2 promotes proliferation, invasion, and metastasis through regulation of the PI3K/AKT signaling pathway in oral squamous cell carcinoma

Proline 4-hydroxylase 2 (P4HA2) is known for its hydroxylase activity, primarily involved in hydroxylating collagen precursors and promoting collagen cross-linking under physiological conditions. Although its overexpression influences a wide variety of malignant tumors' occurrence and development, its specific effects and mechanisms in oral squamous cell carcinoma (OSCC) remain unclear. This study focused on investigating the expression patterns, carcinogenic functions, and underlying mechanisms of P4HA2 in OSCC cells. Various databases, including TCGA, TIMER, UALCAN, GEPIA, and K-M plotter, along with paraffin-embedded samples, were used to ascertain P4HA2 expression in cancer and its correlation with clinicopathological features. P4HA2 knockdown and overexpression cell models were developed to assess its oncogenic roles and mechanisms. The results indicated that P4HA2 was overexpressed in OSCC and inversely correlated with patient survival. Knockdown of P4HA2 suppressed invasion, migration, and proliferation of OSCC cells both in vitro and in vivo, whereas overexpression of P4HA2 had the opposite effects. Mechanistically, the phosphorylation levels of the PI3K/AKT pathway were reduced following P4HA2 silencing. The study reveals that P4HA2 acts as a promising biomarker for predicting prognosis in OSCC and significantly affects metastasis, invasion, and proliferation of OSCC cells through the regulation of the PI3K/AKT signaling pathway.

Expression of Beta-Catenin, Cadherins and P-Runx2 in Fibro-Osseous Lesions of the Jaw: Tissue Microarray Study

Fibrous dysplasia (FD) and hyperparathyroidism-jaw tumor syndrome (HPT-JT) are well-characterized benign bone fibro-osseous lesions. The intracellular mechanism leading to excessive deposition of fibrous tissue and alteration of differentiation processes leading to osteomalacia have not yet been fully clarified. Tissue Microarray (TMA)-based immunohistochemical expression of β-catenin, CK-AE1/AE3, Ki-67, cadherins and P-Runx2 were analyzed in archival samples from nine patients affected by FD and HPT-JT and in seven controls, with the aim of elucidating the contribution of these molecules (β-catenin, cadherins and P-Runx2) in the osteoblast differentiation pathway. β-catenin was strongly upregulated in FD, showing a hyper-cellulated pattern, while it was faintly expressed in bone tumors associated with HPT-JT. Furthermore, the loss of expression of OB-cadherin in osteoblast lineage in FD was accompanied by N-cadherin and P-cadherin upregulation (p < 0.05), while E-cadherin showed a minor role in these pathological processes. P-Runx2 showed over-expression in six out of eight cases of FD and stained moderately positive in the rimming lining osteoblasts in HPT-JT syndrome. β-catenin plays a central role in fibrous tissue proliferation and accompanies the lack of differentiation of osteoblast precursors in mature osteoblasts in FD. The study showed that the combined evaluation of the histological characteristics and the histochemical and immunohistochemical profile of key molecules involved in osteoblast differentiation are useful in the diagnosis, classification and therapeutic management of fibrous-osseous lesions.

Cutaneous desmoid-type fibromatosis: A rare case with molecular profiling

Fibromatoses encompass a broad group of histopathologically similar fibroblastic/myofibroblastic proliferations with divergent clinical manifestations and behavior. Deep (desmoid-type) fibromatoses are typically large, rapidly growing, and locally aggressive tumors that occur in the abdominal wall, mesentery, and extra-abdominal soft tissue, principally the musculature of the trunk and extremities. Most sporadic cases of desmoid fibromatosis harbor inactivating mutations in CTNNB1, the gene encoding beta-catenin. Tumors occurring in the context of familial adenomatous polyposis and Gardner syndrome bear inactivating mutations in APC. By contrast, mutations in CTNNB1 or APC have not been identified in cases of superficial fibromatosis. Cutaneous involvement by desmoid fibromatosis is exceedingly rare. Here we present a 78-year-old male with desmoid-type fibromatosis arising in the dermis of the right medial calf with a pathogenic mutation in CTNNB1 and a variant of unknown significance in APC.

Impact of Histochemistry on biomedical research: looking through the articles published in a long-established histochemical journal

Histochemistry provides the unique opportunity to detect single molecules in the very place where they exert their structural roles or functional activities: this makes it possible to correlate structural organization and function, and may be fruitfully exploited in countless biomedical research topics. Aiming to estimate the impact of histochemical articles in the biomedical field, the last few years citations of articles published in a long-established histochemical journal have been considered. This brief survey suggests that histochemical journals, especially the ones open to a large spectrum of research subjects, do represent an irreplaceable source of information not only for cell biologists, microscopists or anatomists, but also for biochemists, molecular biologists and biotechnologists.

HuR represses Wnt/β-catenin-mediated transcriptional activity by promoting cytoplasmic localization of β-catenin

β-Catenin is the key transcriptional activator of canonical Wnt signaling in the nucleus; thus, nuclear accumulation of β-catenin is a critical step for expressing target genes. β-Catenin accumulates in the nucleus of cancer cells where it activates oncogenic target genes. Hu antigen R (HuR) is a RNA binding protein that regulates multiple post-transcriptional processes including RNA stability. Thus, cytoplasmic HuR protein may be involved in tumorigenesis by stabilizing oncogenic transcripts, but the molecular mechanism remains unclear. Here, we observed that Wnt/β-catenin signaling induced export of the HuR protein, whereas HuR overexpression promoted accumulation of the β-catenin protein in the cytoplasm. Thus, Wnt/β-catenin-mediated transcriptional activity in the nucleus was reduced by overexpressing HuR. These results suggest novel and uncharacterized cytoplasmic β-catenin functions related to HuR-mediated RNA metabolism in cancer cells.

Cytoplasmic expression of Wilms tumor transcription factor-1 (WT1): a useful immunomarker for young-type fibromatoses and infantile fibrosarcoma

There is increasing evidence that Wilms' tumor transcription factor-1 (WT1) is expressed in the cytoplasm of neoplastic cells from different benign and malignant tumors. Only a few studies on WT1 cytoplasmic immunolocalization are available in pediatric tumors. The aim of the present study was to investigate immunohistochemically the expression and distribution of WT1 in a large series of soft tissue fibroblastic/myofibroblastic lesions occurring in children and adolescents. Notably WT1 was not expressed in nodular fasciitis and desmoid-type (adult) fibromatosis, while it stained diffusely and strongly in several infantile-type fibromatoses, such as fibrous hamartoma of infancy, myofibroma/myofibromatosis, and lipofibromatosis. Interestingly, WT1 cytoplasmic expression was also found in all cases (10/10) of infantile fibrosarcomas examined. The present study shows that a diffuse WT1 cytoplasmic expression is of complementary diagnostic value to conventional myofibroblastic markers (α-smooth muscle actin; desmin) in confirming diagnosis of young-type fibromatoses or infantile fibrosarcoma and in ruling out both desmoid-type fibromatoses and nodular fasciitis. WT1 cytoplasmic expression in infantile fibrosarcoma is a novel finding which could be exploitable as an immunomarker for this tumor. Although highly sensitive, WT1 cytoplasmic immunostaining is not specific for infantile fibrosarcoma, and thus it should be evaluated in the context of a wide immunohistochemical panel when pathologists are dealing with spindle cell lesions of soft tissues in children and adolescents. Accordingly we recommend that a correct diagnosis of fibroblastic/myofibroblastic soft tissue lesion in pediatric patients is usually achieved on the basis of a careful correlation of morphological and immunohistochemical findings in the appropriate clinical context. The different cellular localization of WT1, namely nuclear, cytoplasmic or nucleo-cytoplasmic, in different benign and malignant tumors supports the hypothesis that this transcription factor plays a complex role in tumorigenesis, likely as a chameleon protein functioning as either a tumor suppressor gene or an oncogene, depending on cellular context.

Silencing RhoA inhibits migration and invasion through Wnt/β-catenin pathway and growth through cell cycle regulation in human tongue cancer

Ras homolog gene family member A (RhoA) has been identified as a critical regulator of tumor aggressive behavior. In this study, we assessed the role of RhoA in the mechanisms underlying growth, migration, and invasion of squamous cell carcinoma of tongue (TSCC). Stable RhoA knockdown of TSCC cell lines SCC-4 and CAL27 were achieved using Lentiviral transfection. The effects of RhoA depletion on cell migration, invasion, and cell proliferation were determined. The possible underlying mechanism of RhoA depletion on TSCC cell line was also evaluated by determining the expression of Galectin-3 (Gal-3), β-catenin, and matrix metalloproteinase-9 (MMP-9) in vivo. Meanwhile, the underlying mechanism of TSCC growth was studied by analysis of cyclin D1/2, p21CIP1/WAF1, and p27Kip1 protein levels. Immunohistochemical assessments were performed to further prove the alteration of Gal-3 and β-catenin expression. We found that, in mice injected with human TSCC cells in the tongue, RhoA levels were higher in primary tumors and metastasized lymph nodes compared with those in the normal tissues. Silencing of RhoA significantly reduced the tumor growth, decreased the levels of Gal-3, β-catenin, MMP-9, and cyclin D1/2, and increased the levels of p21CIP1/WAF1 and p27Kip1. In vitro, RhoA knockdown also led to inhibition of cell migration, invasion, and proliferation. Our data suggest that RhoA plays a significant role in TSCC progression by regulating cell migration and invasion through Wnt/β-catenin signaling pathway and cell proliferation through cell cycle regulation, respectively. RhoA might be a novel therapeutic target of TSCC.

Preoperative chemoradiotherapy in rectal cancer induces changes in the expression of nuclear β-catenin: prognostic significance

BACKGROUND

Preoperative chemoradiotherapy (CRT) is the cornerstone of treatment for locally advanced rectal cancer (LARC). Although high local control is achieved, overall rates of distant control remain suboptimal. Colorectal carcinogenesis is associated with critical alterations of the Wnt/β-catenin pathway involved in proliferation and survival. The aim of this study was to assess whether CRT induces changes in the expression of β-catenin/E-cadherin, and to determine whether these changes are associated with survival.

METHODS

The Immunohistochemical expression of nuclear β-catenin and membranous E-cadherin was prospectively analysed in tumour blocks from 98 stage II/III rectal cancer patients treated with preoperative CRT. Tumour samples were collected before and after CRT treatment. All patients were treated with pelvic RT (46-50 Gy in 2 Gy fractions) and 5-fluorouracil (5FU) intravenous infusion (225 mg/m2) or capecitabine (825 mg/m2) during RT treatment, followed by total mesorectal excision (TME). Disease-free survival (DFS) was analysed using the Kaplan-Meier method and a multivariate Cox regression model was employed for the Multivariate analysis.

RESULTS

CRT induced significant changes in the expression of nuclear β-catenin (49% of patients presented an increased expression after CRT, 17% a decreased expression and 34% no changes; p = 0.001). After a median follow-up of 25 months, patients that overexpressed nuclear β-catenin after CRT showed poor survival compared with patients that experienced a decrease in nuclear β-catenin expression (3-year DFS 92% vs. 43%, HR 0.17; 95% CI 0.03 to 0.8; p = 0.02). In the multivariate analysis for DFS, increased nuclear β-catenin expression after CRT almost reached the cut-off for significance (p = 0.06).

CONCLUSIONS

In our study, preoperative CRT for LARC induced significant changes in nuclear β-catenin expression, which had a major impact on survival. Finding a way to decrease CRT resistance would significantly improve LARC patient survival.

Histochemistry as an irreplaceable approach for investigating functional cytology and histology

In agreement with the evolution of histochemistry over the last fifty years and thanks to the impressive advancements in microscopy sciences, the application of cytochemical techniques to light and electron microscopy is more and more addressed to elucidate the functional characteristics of cells and tissue under different physiological, pathological or experimental conditions. Simultaneously, the mere description of composition and morphological features has become increasingly sporadic in the histochemical literature. Since basic research on cell functional organization is essential for understanding the mechanisms responsible for major biological processes such as differentiation or growth control in normal and tumor tissues, histochemical Journals will continue to play a pivotal role in the field of cell and tissue biology in all its structural and functional aspects.

Stem cell populations in the heart and the role of Isl1 positive cells

Cardiac progenitor cells are multipotent stem cells isolated from both embryonic and adult hearts in several species and are able to differentiate at least into smooth muscle cells, endothelial cells and cardiomyocytes. The embryonic origin of these cells has not yet been demonstrated, but it has been suggested that these cells may derive from the first and secondary heart fields and from the neural crest. In the last decade, two diffe-rent populations of cardiac progenitor or stem cells have been identified and isolated, i.e., the Islet1 positive (Isl1+) and c-Kit positive (c-Kit+)/Stem Cell Antigen-1 positive (Sca-1+) cells. Until 2012, these two populations have been considered two separate entities with different roles and a different origin, but new evidence now suggests a con-nection between the two populations and that the two populations may represent two subpopulations of a unique pool of cardiac stem cells, derived from a common immature primitive cell. To find a common consensus on this concept is very important in furthe-ring the application of stem cells to cardiac tissue engineering.