Immunohistochemical analysis of beta-catenin, E-cadherin and p53 in canine gastrointestinal epithelial tumors

Activation of the Wnt/β-catenin signaling pathway and CTNNB1 mutations in canine intestinal epithelial proliferative lesions

Nuclear expression of β-catenin has been reported in canine intestinal epithelial tumors (IETs) and colorectal inflammatory polyps (CIPs) with dysplastic epithelia. However, the role of the Wnt/β-catenin signaling pathway in these lesions remains unclear. To investigate the association between the nuclear β-catenin expression and the activation of the Wnt/β-catenin signaling pathway, immunohistochemistry and mutation analyses were conducted on 64 IETs and 20 CIPs. IETs and CIPs with β-catenin nuclear and/or cytoplasm immunolabeling were classified as β-catenin (+). The immunostaining scores of c-Myc and Cyclin D1 and Ki-67 index were significantly higher in β-catenin (+) cases than in β-catenin (-) cases. Identical APC mutations (p.E154D and p.K155X) were detected in 6/41 β-catenin (+) IETs; all 6 of IETs with APC mutations were Jack Russell Terriers. CTNNB1 mutations were detected in 29/42 β-catenin (+) IETs, 3/11 β-catenin (+) CIPs, and 2/22 β-catenin (-) IETs, most of which were hotspots associated with human colorectal carcinoma. In one Miniature Dachshund diagnosed with a CIP that subsequently developed into an IET, the same CTNNB1 mutation was detected in both lesions. The immunohistochemical results suggest that cell proliferative activity in β-catenin (+) cases may be associated with activation of the Wnt/β-catenin signaling pathway. The mutation analysis results suggest that CTNNB1 mutations may be associated with cytoplasmic β-catenin accumulation in IET and CIP. Furthermore, the dysplastic epithelium in CIP may progress to IET through the activation of the Wnt/β-catenin signaling pathway by the CTNNB1 mutation.

High-fat diet enhances cell proliferation and compromises intestinal permeability in a translational canine intestinal organoid model

BACKGROUND

Emerging evidence underscores the responsiveness of the mammalian intestine to dietary cues, notably through the involvement of LGR5 + intestinal stem cells in orchestrating responses to diet-driven signals. However, the effects of high-fat diet (HFD) on these cellular dynamics and their impact on gut integrity remain insufficiently understood. Our study aims to assess the multifaceted interactions between palmitic acid (PA), cell proliferation, and the intestinal epithelial barrier using a canine colonoid model. Canine models, due to their relevance in simulating human intestinal diseases, offer a unique platform to explore the molecular mechanisms underlying HFD derived intestinal dysfunction.

RESULTS

Canine colonoids were subjected to PA exposure, a surrogate for the effects of HFD. This intervention revealed a remarkable augmentation of cell proliferative activity. Furthermore, we observed a parallel reduction in transepithelial electrical resistance (TEER), indicating altered epithelium barrier integrity. While E-cadherin exhibited consistency, ZO-1 displayed a noteworthy reduction in fluorescence intensity within the PA-exposed group.

CONCLUSIONS

By employing canine intestinal organoid systems, we provide compelling insights into the impact of PA on intestinal physiology. These findings underscore the importance of considering both cell proliferative activity and epithelial integrity in comprehending the repercussions of HFDs on intestinal health. Our study contributes to a deeper understanding of the consequences of HFD on intestinal homeostasis, utilizing valuable translational in vitro models derived from dogs.

Three-Dimensional Morphogenesis in Canine Gut-on-a-Chip Using Intestinal Organoids Derived from Inflammatory Bowel Disease Patients

Canine intestines possess similarities in anatomy, microbiology, and physiology to those of humans, and dogs naturally develop spontaneous intestinal disorders similar to humans. Overcoming the inherent limitation of three-dimensional (3D) organoids in accessing the apical surface of the intestinal epithelium has led to the generation of two-dimensional (2D) monolayer cultures, which expose the accessible luminal surface using cells derived from the organoids. The integration of these organoids and organoid-derived monolayer cultures into a microfluidic Gut-on-a-Chip system has further evolved the technology, allowing for the development of more physiologically relevant dynamic in vitro intestinal models. In this study, we present a protocol for generating 3D morphogenesis of canine intestinal epithelium using primary intestinal tissue samples obtained from dogs affected by inflammatory bowel disease (IBD). We also outline a protocol for generating and maintaining 2D monolayer cultures and intestine-on-a-chip systems using cells derived from the 3D intestinal organoids. The protocols presented in this study serve as a foundational framework for establishing a microfluidic Gut-on-a-Chip system specifically designed for canines. By laying the groundwork for this innovative approach, we aim to expand the application of these techniques in biomedical and translational research, aligning with the principles of the One Health Initiative. By utilizing this approach, we can develop more physiologically relevant dynamic in vitro models for studying intestinal physiology in both dogs and humans. This has significant implications for biomedical and pharmaceutical applications, as it can aid in the development of more effective treatments for intestinal diseases in both species.

Validation of p53 Immunohistochemistry (PAb240 Clone) in Canine Tumors with Next-Generation Sequencing (NGS) Analysis

In human medicine, p53 immunohistochemistry (IHC) is a common method that is used for the identification of tumors with TP53 mutations. In veterinary medicine, several studies have performed IHC for p53 in canine tumors, but it is not known how well it actually predicts the mutation. The aim of this study was to estimate the accuracy of the IHC method for p53 (clone PAb240) using a lab-developed NGS panel to analyze TP53 mutations in a subset of malignant tumors in dogs. A total of 176 tumors were analyzed with IHC and then 41 were subjected to NGS analysis; among them, 15 were IHC positive and 26 were negative, and 16 out of 41 (39%) were found to be inadequate for NGS analysis. Excluding the non-evaluable cases at NGS, of the remaining eight IHC-positive cases, six were mutants and two were wild-type. Among the 17 IHC-negative cases, 13 were wild type, and 4 were mutants. The sensitivity was 60%, specificity was 86.7%, and the accuracy was 76%. These results suggest that when using IHC for p53 with this specific antibody to predict mutation, up to 25% wrong predictions can be expected.

E-cadherin Expression in Canine Gastric Carcinomas: Association with Clinicopathological Parameters

E-cadherin (E-cad) is a cell-adhesion molecule known for its tumor-invasion suppressor function. E-cad expression was examined immunohistochemically in a series of canine tissue samples, including normal gastric mucosa (NGM; n = 3), gastric carcinomas (GC; n = 33), adjacent non-neoplastic mucosa (NNM; n = 32), neoplastic emboli (n = 16) and metastatic lesions (n = 9). The relationship between E-cad expression and clinicopathological features were investigated. In NGM, epithelial cells showed strong latero-lateral membranous expression of E-cad, and this pattern was considered normal. The membranous staining was preserved in all specimens of NNM (100%), whereas abnormal E-cad expression was found in 87.9% of the GCs. A marked difference in E-cad expression was observed between normal and malignant tissues (p < 0.0002). Abnormal E-cad expression was significantly more frequent in poorly/undifferentiated carcinomas (96%) and diffuse (95%) and indeterminate carcinomas (100%) than in well-differentiated/intestinal ones (62.5%; p = 0.0115 and p = 0.0392, respectively). There was significant association between abnormal E-cad expression and the depth of invasion (p = 0.0117), and the presence neoplastic emboli (p = 0.0194). No statistically significant differences in E-cad expression were observed concerning tumor location, histological type according to WHO classification, and presence of metastatic lesions. Therefore, deregulation of E-cad expression may play a role in canine gastric carcinogenesis and in tumor progression; moreover, it might be a prognostic tool for canine gastric cancer.

Sox9, Hopx, and survivin and tuft cell marker DCLK1 expression in normal canine intestine and in intestinal adenoma and adenocarcinoma

Self-renewal of the intestinal epithelium originates from stem cells located at the crypt base. Upregulation of various stem cell markers in intestinal epithelial neoplasms indicates a potential role of stem cells in tumorigenesis. In this study, the immunoreactivity of potential intestinal stem cell markers ( Sry box transcription factor 9 [Sox9], homeodomain-only protein [Hopx], survivin) and tuft cell marker doublecortin-like kinase 1 (DCLK1) in normal canine intestine and intestinal epithelial neoplasms was investigated. Formalin-fixed paraffin-embedded (FFPE) small and large intestine as well as intestinal neoplasms (55 colorectal adenomas [CRAs], 17 small intestinal adenocarcinomas [SICs], and 12 colorectal adenocarcinomas [CRCs]) were analyzed immunohistologically. Potential stem cell markers Sox9, Hopx, and survivin were detected in the crypts of normal canine small and large intestine. DCLK1+ tuft cells were present in decreasing numbers along the crypt-villus axis of the jejunum and rarely detectable in large intestine. In canine intestinal epithelial tumors, nuclear Sox9 immunoreactivity was detectable in 84.9% (CRA), 80% (CRC), and 77% of epithelial neoplastic cells (SIC). Hopx and survivin were expressed within cytoplasm and nuclei of neoplastic cells in benign and malignant tumors. DCLK1 showed a cytoplasmic reaction within neoplastic cells. The combined score of Hopx, DCLK1, and survivin varied among the examined cases. Overall, malignant tumors showed lower DCLK1 scores but higher Hopx scores in comparison with benign tumors. For survivin, no differences were detectable. In conclusion, stem cell markers Sox9, Hopx, and survivin were detectable at the crypt base and the immunoreactivity of Sox9, DCLK1, survivin, and Hopx was increased in canine intestinal adenomas and adenocarcinomas compared with normal mucosa.

EPRS/GluRS promotes gastric cancer development via WNT/GSK-3β/β-catenin signaling pathway

BACKGROUND

Glutamyl-prolyl-tRNA synthetase (EPRS/GluRS) is primarily part of the multi-synthetase complex that may play a key role in cancer development. However, the biological function, molecular mechanism, and inhibitor of EPRS have not been investigated in gastric cancer (GC).

METHODS

Immunohistochemistry was performed to detect the expression of EPRS in human gastric tumor tissues. Knocking down of EPRS, cell-derived xenograft mouse model, and patient-derived xenograft mouse model was used to identify the biological function of EPRS. Immunoprecipitation was applied to elucidate the interaction between EPRS and SCYL2. Computer docking model and multiple in vitro and in vivo experiments were conducted to discover EPRS inhibitors.

RESULTS

Here, we report that EPRS is frequently overexpressed in GC tissues compared to that adjacent controls and its overexpression predicts poor prognosis in GC patients. Functionally, high expression of EPRS positively co-relates with GC development both in vitro and in vivo. Mechanistically, EPRS directly binds with SCYL2 to enhance the activation of WNT/GSK-3β/β-catenin signaling pathway and the accumulation of β-catenin in the nuclear, leading to GC cell proliferation and tumor growth. Moreover, we identified that xanthoangelol (XA) and 4-hydroxyderricin (4-HD) can directly bind to EPRS to block WNT/GSK-3β/β-catenin signaling pathway. More importantly, XA and 4-HD restrain gastric cancer patient-derived xenograft tumor growth and Helicobacter pylori combined with alcohol-induced atrophic gastritis and gastric tumorigenesis.

CONCLUSION

These findings unveil a promising strategy for GC prevention and therapy by targeting EPRS-mediated WNT/GSK-3β/β-catenin cascades. Moreover, XA and 4-HD may be effective reagents used for GC prevention and therapy.

Canine Gastric Carcinomas: A Histopathological and Immunohistochemical Study and Similarities with the Human Counterpart

Simple Summary

Gastric carcinoma (GC) continues to be one of the leading causes of death in humans and is the most common neoplasm in the stomachs of dogs. In both species, previous studies have demonstrated that the disease is heterogeneous, with genetic and environmental factors playing a quintessential role in disease pathogenesis. Compared to humans, the incidence of gastric carcinoma in dogs is low although, in a small number of breeds, a higher incidence has been reported. In dogs, the etiology and molecular pathways involved remain largely unknown. This retrospective study reviews current signalment data, evaluates the inflammatory component and association with Helicobacter spp. presence in various canine gastric carcinoma histological subtypes, and investigates potential molecular pathways involved in one of the largest study cohorts to date. The benefit of such a comparative study is to highlight the parallel histological features and molecular pathways between dogs and humans.

Abstract

Canine gastric carcinoma (CGC) affects both sexes in relatively equal proportions, with a mean age of nine years, and the highest frequency in Staffordshire bull terriers. The most common histological subtype in 149 CGC cases was the undifferentiated carcinoma. CGCs were associated with increased chronic inflammation parameters and a greater chronic inflammatory score when Helicobacter spp. were present. Understanding the molecular pathways of gastric carcinoma is challenging. All markers showed variable expression for each subtype. Expression of the cell cycle regulator 14-3-3σ was positive in undifferentiated, tubular and papillary carcinomas. This demonstrates that 14-3-3σ could serve as an immunohistochemical marker in routine diagnosis and that mucinous, papillary and signet-ring cell (SRC) carcinomas follow a 14-3-3σ independent pathway. p16, another cell cycle regulator, showed increased expression in mucinous and SRC carcinomas. Expression of the adhesion molecules E-cadherin and CD44 appear context-dependent, with switching within tumor emboli potentially playing an important role in tumor cell survival, during invasion and metastasis. Within neoplastic emboli, acinar structures lacked expression of all markers, suggesting an independent molecular pathway that requires further investigation. These findings demonstrate similarities and differences between dogs and humans, albeit further clinicopathological data and molecular analysis are required.