Expression of β-catenin and AXIN2 in ameloblastomas

Targeting BRD4 attenuates the stemness and aggressiveness of ameloblastoma

BACKGROUND

BRD4, belonging to the bromodomain extra-terminal (BET) protein family, plays a unique role in tumor progression. However, the potential impact of BRD4 in ameloblastoma (AM) remains largely unknown. Herein, we aimed to assess the expression and functional role of BRD4 in AM.

METHODS

The expression level of BRD4 was assessed by immunohistochemistry. The proliferation, migration, invasion, and tumorigenic abilities of AM cells were assessed by a series of assays. To explore the molecular expression profile of BRD4-depleted AM cells, RNA sequencing (RNA-seq) was performed. Bioinformatic analysis was performed on AM expression matrices obtained from the Gene Expression Omnibus (GEO). The therapeutic efficacy of BET-inhibitors (BETi) was assessed with AM patient-derived organoids.

RESULTS

Upregulation of BRD4 was observed in conventional AMs, recurrent AMs, and ameloblastic carcinomas. Depletion of BRD4 inhibited proliferation, invasion, migration, and tumorigenesis in AM. Administration of BETi attenuated the aggressiveness of AM and the growth of AM patient-derived organoids. Bioinformatic analysis indicated that BRD4 may promote AM progression by regulating the Wnt pathway and stemness-associated pathways.

CONCLUSION

BRD4 increases the aggressiveness and promotes the recurrence of ameloblastoma by regulating the Wnt pathway and stemness-associated pathways. These findings highlight BRD4 as a promising therapeutic target in AM management.

Elevated pulmonary levels of Axin2 in mice exposed to herbicide 2,4-D with or without endotoxin

2,4-Dichlorophenoxyacetic acid (2,4-D), a member of the phenoxy family of herbicides is commonly used in agriculture for controlling broadleaf weeds but its uncontrolled and incoherent use has been linked to incidences of lung toxicity. The present study aimed to understand the molecular mechanisms behind the 2,4-D alone or in combination with endotoxin (lipopolysaccharide [LPS]) induced pulmonary toxicity. Blood and lung samples were collected from Swiss albino mice (n = 48) following chronic exposure to high (37 mg/kg; 1/10th of LD₅₀ ) and low (18.5 mg/kg; 1/20th of LD₅₀ ) doses of 2,4-D alone or in combination with endotoxin (80 µg/animal). Transcriptome analysis revealed Wnt Canonical signaling as one of the top dysregulated pathways in mice lung following exposure to 2,4-D with and without endotoxin (LPS) co-exposure. Global view of differentially expressed genes showed increased messenger RNA expression of Axin2 by 0.26, 2.58, 3.14, 2.59, and 2.97 folds following exposure to LPS, high dose alone or in combination with LPS and low dose alone or in combination with LPS, respectively. The microarray data were validated using quantitative polymerase chain reaction and immunohistochemistry. Furthermore, the plasma concentration of Axin2 was elevated in the high dose group as revealed by Sandwich ELISA. The data taken together suggest a role of Axin2 to activate the Canonical Wnt signaling pathway in 2,4-D and or endotoxin-induced lung damage in mice.

The Expression of Selected Wnt Pathway Members (FZD6, AXIN2 and β-Catenin) in Canine Oral Squamous Cell Carcinoma and Acanthomatous Ameloblastoma

The Wnt signaling pathway is well known to be involved in many types of human cancer; however, in veterinary medicine, the investigation of individual Wnt members' expression, and their role in or association with oral tumor pathogenesis, is still underevaluated. We aim to determine the expression pattern of Frizzled-6 (FZD6) as one of the Wnt receptors in two of the most common canine oral neoplastic lesions-canine oral squamous cell carcinoma (COSCC) and canine acanthomatous ameloblastoma (CAA). While COSCC is a malignant tumor with aggressive biological behavior and a tendency to metastasize, CAA is a benign tumor with high local invasiveness. In CAA, the expression of FZD6 was mostly located in the center of the epithelial tumorous tissue, and cells exhibiting features of squamous metaplasia were strongly positive. In well-differentiated COSCC, FZD6 was expressed in the tumorous epithelium as well as the tumorous stroma. There was a negative correlation between cytokeratin expression and FZD6 expression in COSCC, where the central parts of the epithelial tumorous tissue were often FZD6-negative. The non-differentiated COSCC with low expression of cytokeratin exhibited a diffuse FZD6 signal. The invasive front with areas of tumor budding exhibited high FZD6 expression with a loss of cytokeratin expression. Moreover, the expression of β-catenin and AXIN2 was increased in comparison to gingiva. In conclusion, our study revealed significant differences in the expression patterns and the levels of FZD6 between COSCC and CAA, indicating the differential engagement of the Wnt pathway in these tumors.

APC and AXIN2 Are Promising Biomarker Candidates for the Early Detection of Adenomas and Hyperplastic Polyps

Aberrant activation of the WNT/CTNNB1 pathway is notorious in colorectal cancer (CRC). Here, we demonstrate that the expression of specific and crucial WNT signaling pathway genes is linked to disease progression in colonic adenomatous (AP) and hyperplastic (HP) polyps in an Iranian patient population. Thus, we highlight potential gene expression profiles as candidate novel biomarkers for the early detection of CRC. From a 12-month study (2016-2017), 44 biopsy samples were collected during colonoscopy from the patients with colorectal polyps and 10 healthy subjects for normalization. Clinical and demographic data were collected in all cases, and mRNA expression of APC, CTNNB1, CDH1, AXIN1, and AXIN2 genes was investigated using real-time polymerase chain reaction (PCR). CTNNB1 and CDH1 expression levels were unaltered in AP and HP subjects, whereas mRNA expression of APC was decreased in AP contrasted with HP subjects, with a significant association between APC downregulation and polyp size. Although AXIN1 showed no changes between AP and HP groups, a significant association between AXIN1 and dysplasia grade was found. Also, significant upregulation of AXIN2 in both AP and HP subjects was detected. In summary, we have shown increased expression of AXIN2 and decreased expression of APC correlating with grade of dysplasia and polyp size. Hence, AXIN2 and APC should be explored as biomarker candidates for early detection of AP and HP polyps in CRC.

microRNA-544 promoted human osteosarcoma cell proliferation by downregulating AXIN2 expression

microRNAs (miRNAs) perform various oncogenic or tumor suppressor functions in carcinogenesis. Currently, the underlying mechanisms of miRNAs in osteosarcoma (OS) are poorly understood. In the present study, it is demonstrated that expression of miR-544 was markedly upregulated in OS cells and clinical tissues. Furthermore, overexpression of miR-544 enhanced OS cell proliferation in vitro. Bioinformatics analysis indicated that miR-544 may target the 3′-untranslated region of axis formation inhibitor 2, which was validated using luciferase reporter gene assays. The present study demonstrated a vital role for miR-544 in promoting OS cell proliferation, indicating that it may represent a novel prognostic factor or therapeutic target for OS.

Immunoexpression of Wnt/β-catenin signaling pathway proteins in ameloblastoma and calcifying cystic odontogenic tumor

Background

Wnt/β-catenin signaling pathway is essential for the beginning of odontogenesis and may be involved in the development and progression of some odontogenic tumors. Thus, the aim of this study was to comparatively evaluate the immunohistochemical expression of Wnt/β-catenin signaling pathway proteins in a series of AME and CCOT.

Material and Methods

Immunohistochemical reactions were performed using antibodies against Wnt1, Wnt5a and β-catenin in 17 cases of solid AME and 6 cases of CCOT.

Results

In the AME group, Wnt1 and Wnt5a were identified in the epithelium in most of the cases, and β-catenin was mainly identified in the cytoplasm of the tumoral cells. In the CCOT group, Wnt1 and Wnt5a were identified in the epithelium and in the ghost cells in almost all the cases, and β-catenin was mainly identified in the cytoplasm and in the nuclei of the tumoral cells.

Conclusions

These results contribute to support the importance of Wnt/β-catenin signaling pathway proteins in AME and CCOT tumorigenesis. The abnormal expression of cytoplasmic and/or nuclear β-catenin appears to contribute to the development of both AME and CCOT. In addition, it is possible that Wnt1 and Wnt5a expression in ghost cells can contribute to its histogenesis in CCOT.

Key words:Ameloblastoma, β-catenin, calcifying cystic odontogenic tumor, immunohistochemistry, Wnt.

Beta-catenin in disease

In continuation with the previous review on “β-catenin in health”, in this review we discuss the role of β-catenin in the pathogenesis of common oral lesions in the oral and maxillofacial region- oral potentially malignant disorders, their progression to oral squamous cell carcinoma, salivary gland tumors and odontogenic tumours. This review is based on a pubmed search of all the lesions included in the review.

miR-107 promotes hepatocellular carcinoma cell proliferation by targeting Axin2

BACKGROUND

A large number of studies demonstrated that microRNAs play important roles in the progression and development of human cancers. However, the expression level of miR-107 and its biological function in hepatocellular carcinoma (HCC) remains unclear.

METHOD

Quantitative real-time PCR (qRT-PCR) was used to evaluate the expression level of miR-107 in HCC tissues and cell lines. Then, we explored the function of miR-107 to determine its potential roles on HCC cell proliferation in vitro. Luciferase reporter assay was used to confirm the target gene of miR-107, and the results were validated in cell lines.

RESULTS

miR-107 was significantly up-regulated in HCC tissues and cell lines. The enforced expression of miR-107 was able to promote cell proliferation in HepG2 cells. At the molecular level, our results suggested that expression of Axin2 was negatively regulated by miR-107.

CONCLUSION

Our observations suggested that miR-107 could promote HCC cells proliferation via targeting Axin2 and might represent a potential therapeutic target for HCC.