Perineural differentiation in neurotized nevi

BACKGROUND

Perineuriomatous melanocytic nevi are rare and this may indicate the similar embryological source of melanocytes and peripheral nerves in the neural crest. Neurotized melanocytic nevi may resemble nerve sheath tumors histologically, and show schwannian differentiation. However, literature on whether neurotized nevi differentiate into perineural cells is controversial. We examined our cases of neurotized nevi for evidence of perineural differentiation.

MATERIALS AND METHODS

A total of 100 benign nevi with large neurotized component (microscopically involved a low power field 4.2 mm in diameter) were prospectively evaluated in excisional biopsy samples. Immunohistochemical stainings for EMA, Claudin1, Glut1 and neurofilament were performed.

RESULTS

Perineural differentiation was immunohistochemically detected in the neurotized component of the nevi in 61% of the cases with EMA and in all the cases with Glut1 and Claudin1. Axonal differentiation was not detected with neurofilament. The expression pattern, especially with Glut1, was usually in form of partial or complete staining surrounding the Meissner's corpuscle-like structure (MCLS). Also, a linear/curvilinear staining pattern was observed particularly with Claudin1. A diffuse staining pattern with EMA, Glut1 and Claudin1 was detected in a case with a microscopically distinct whorl structure, and in which spindle cells are separated from the superficial epithelioid melanocytes with an abrupt transition histologically. These findings of the case are compatible with previous reports of perineuromatous nevus.

CONCLUSION

Perineural differentiation is not uncommon and immunohistochemically observed in all nevi with a relatively large component of neurotization. To prevent misdiagnosing desmoplastic melanoma and overtreating patients, it is crucial to be aware of perineuromatous nevi.

USP40 promotes hepatocellular carcinoma cell proliferation, migration and stemness by deubiquitinating and stabilizing Claudin1

BACKGROUND

Hepatocellular carcinoma (HCC) is a prevalent malignant tumor that poses a major threat to people's lives and health. Previous studies have found that multiple deubiquitinating enzymes are involved in the pathogenesis of HCC. The purpose of this work was to elucidate the function and mechanism of the deubiquitinating enzyme USP40 in HCC progression.

METHODS

The expression of USP40 in human HCC tissues and HCC cell lines was investigated using RT-qPCR, western blotting and immunohistochemistry (IHC). Both in vitro and in vivo experiments were conducted to determine the crucial role of USP40 in HCC progression. The interaction between USP40 and Claudin1 was identified by immunofluorescence, co-immunoprecipitation and ubiquitination assays.

RESULTS

We discovered that USP40 is elevated in HCC tissues and predicts poor prognosis in HCC patients. USP40 knockdown inhibits HCC cell proliferation, migration and stemness, whereas USP40 overexpression shows the opposite impact. Furthermore, we confirmed that Claudin1 is a downstream gene of USP40. Mechanistically, USP40 interacts with Claudin1 and inhibits its polyubiquitination to stabilize Claudin1 protein.

CONCLUSIONS

Our study reveals that USP40 enhances HCC malignant development by deubiquitinating and stabilizing Claudin1, suggesting that targeting USP40 may be a novel approach for HCC therapy.

Expression of TLE1, INI1, β-catenin, Claudin1, CK7, CK19, SS18 and calponin in synovial sarcoma

Background and Objectives

Synovial sarcomas (SS) are enigmatic soft tissue tumors, which are yet to have a defined cell of origin. SS have a variety of differential diagnosis depending upon the age of the patient and the site of presentation. This makes diagnosis cumbersome unless the specific fusion SS18:SSX is identified by reverse transcription-polymerase chain reaction (RT-PCR) or fluorescence in situ hybridization (FISH). Immunohistochemistry is a useful tool in resource-poor settings in helping to narrow the differentials and help diagnose this tumor. This study set about assessing possible candidate immunohistochemical markers in their utility to recognize SS.

Methods

Forty cases of SS, proven by FISH were included. A tissue microarray (TMA) was constructed, and immunohistochemistry was done using antibodies - TLE1 (OTI1F5), β-catenin (14), INI1 (MRQ-27), CK7 (OV-TL), CK19 (polyclonal), SS18 (polyclonal), calponin (CALP), and claudin1 (Polyclonal). The expression was analyzed to arrive at sensitivity and specificity.

Results

TLE1 had a sensitivity of 92.5% and a specificity of 100%; β-Catenin had a sensitivity of 17.5% and specificity of 100%; Calponin had a sensitivity of 97.5% and a specificity of 81.25%; SS18 had a sensitivity of 95% and specificity of 100%; INI1 had a sensitivity of 95% and specificity of 100%; CK7 had a sensitivity of 90% and specificity of 87.5%; CK19 had a sensitivity of 90% and a specificity of 59.38%; and Claudin had a sensitivity of 85% and a specificity of 78.12%.

Interpretation and Conclusions

The study showed both TLE1 and SS18 are robust diagnostic markers of synovial sarcoma with a sensitivity of 92% and 95%, respectively. INI1 can be used to discriminate SS from nonepithelioid and nonrhabdoid differentials. Calponin expression is helpful to differentiate poorly differentiated SS from its mimics. CK7 is a better marker than CK19 and can be used as a replacement for EMA in the initial screening panel. The use of claudin1 was restricted to delineating the epithelial component. β-Catenin had poor sensitivity, restricting its utility in SS.

Human antigen R (HuR) and Cold inducible RNA-binding protein (CIRP) influence intestinal mucosal barrier function in ulcerative colitis by competitive regulation on Claudin1

To investigate the effects of RNA-binding proteins cold-inducible RNA binding protein (CIRP) and human antigen R (HuR) on expression of Claudin1 and mucosal barrier function in ulcerative colitis (UC). The clinical specimens of UC patients and healthy volunteers were collected. In the clinical experiments, the expressions of CIRP, Claudin1, and HuR, along with their correlations in tissues of UC patients were analyzed by qRT-PCR, Western blot and Pearson correlation coefficient, respectively. The chi-square test was utilized to assess the relevance between CIRP/HuR/Claudin1 level and clinicopathological characteristics of UC patients. The in vitro and in vivo models of UC were established by lipopolysaccharide treatment or dextran sulfate sodium injection. For cell experiments, after loss- and gain-of-function, the roles of CIRP or HuR in the apoptosis and proliferation of enterocytes were examined by flow cytometry and CCK-8 assay. The intestinal epithelial barrier function was inspected after determination on transepithelial electrical resistance value, horseradish peroxidase permeability and expressions of tight junction proteins (Occludin, ZO-1, and JAM-1). The relationship between HuR, CIRP, and Claudin1 was performed by RNA immunoprecipitation and dual-luciferase reporter gene assay. For in vivo experiments, the disease activity index score, weight loss and colon length of mice were assessed to observe the effect of CIRP or HuR on the UC mouse models. Histological analysis of colon tissues was conducted by H&E staining. FITC-dextran tracking was applied to inspect the intestinal mucosal barrier function of UC mouse models. In this study, high expression of CIRP and low expressions of HuR and Claudin1 were observed in patients, cells and mouse models of UC. The expressions of CIRP, HuR, and Claudin1 were correlated with the severity of patients with UC. There was a negative correlation between CIRP and Claudin1, and as a positive correlation between HuR and Claudin1. Claudin1 can be suppressed by CIRP, while enhanced by HuR. HuR and CIRP can competitively bind to Claudin1. HuR upregulation or CIRP downregulation promoted proliferation, suppressed apoptosis and ameliorated the damage of the barrier function in enterocytes. The in vivo experiments verified that the ameliorated damage of the intestinal mucosal barrier function in UC mice occurred with HuR overexpression or CIRP knockdown. CIRP and HuR confer pivotal effect on the intestinal mucosal barrier function of UC through competitively binding to Claudin1 mRNA.

UNC13C Suppress Tumor Progression via Inhibiting EMT Pathway and Improves Survival in Oral Squamous Cell Carcinoma

Potential function of UNC13C in variety of cancers including, oral squamous cell carcinoma (OSCC) remains obscure. In the present study, immunohistochemical staining in tissue microarrays containing 268 OSCC samples showed that UNC13C protein levels were inversely correlated with AJCC Stage III and IV (P = 0.002) and death (P = 0.0134). Patients with lower UNC13C expression had a significantly shorter survival (P = 0.0231) than those with higher UNC13C expression. We also identified decreased overall UNC13C expression in oral cancer cell lines. In addition, our functional analysis of UNC13C shows that overexpression of UNC13C inhibited migration and invasion capacities of SCC-9 and SAS cells compared with the empty plasmid transfected cells. Further experiments suggested that transcription factors (Slug, Snail, Twist, and ZEB1) and mesenchymal marker (Vimentin) were down regulated and Tight Junction Protein (Claudin1) was up regulated after UNC13C overexpression in SCC9 and SAS cells. The novel role of UNC13C is revealed for the first time in OSCC. In summary, these results suggest that UNC13C as a novel tumor suppressor and an essential regulator of EMT signaling pathway during OSCC progression, and thus it could be used as a target for preventing oral cancer metastasis.

FH535 inhibits proliferation and migration of colorectal cancer cells by regulating CyclinA2 and Claudin1 gene expression

Wnt signaling pathway plays a major role in the progression of colorectal cancer (CRC). Small molecules which can cut off this signal transduction can be promising anti-cancer drugs for CRC therapy. Therefore, we aimed to investigate the mechanisms of FH535, an inhibitor of the Wnt signaling pathway, on inhibiting proliferation and migration of colorectal cancer cells DLD-1 and SW620. We found that FH535 could significantly suppress the growth of DLD-1 and SW620 cells in a concentration-dependent and time-dependent manner. The results of cell cycle tests showed that FH535 could significantly induce G2/M arrest in colorectal cancer cells. Transwell and Wound-healing assays revealed that FH535 notably inhibited cell migration. Moreover, we found that FH535 down-regulated β-catenin and CyclinA2 expressions while up-regulating Claudin-1 expression at both mRNA and protein levels, which may contribute to the FH535-induced inhibitory effect on proliferation and migration in human colorectal cancer cells. Our study revealed that FH535 inhibited proliferation and migration of colorectal cancer cells by regulating CyclinA2 and Claudin1 gene expression, which enriches regulatory network of FH535 and may contribute to being promising anti-cancer drugs for CRC therapy.

Delocalized Claudin-1 promotes metastasis of human osteosarcoma cells

Tight junction proteins (TJPs) including Claudins, Occludin and tight junction associated protein Zonula occludens-1 (ZO-1), are the most apical component of junctional complex that mediates cell-cell adhesion in epithelial and endothelial cells. In human malignancies, TJPs are often deregulated and affect cellular behaviors of tumor cells. In this study, we investigated alternations of TJPs and related biological characteristics in human osteosarcoma (OS). Claudin1 was increased in the metastatic OS cells (KRIB and KHOS) compared with the normal osteoblast cells (hFOB1.19) or primary tumor cells (HOS and U2OS), whereas no significant difference was found in Occludin and ZO-1. Immunohistochemistry, immunofluorescence and Western blotting revealed that Claudin1 was initially localized at cell junctions of normal osteoblasts, but substantially delocalized to the nucleus of metastatic OS cells. Phenotypically, inhibition of the nucleus Claudin1 expression compromised the metastatic potential of KRIB and KHOS cells. Moreover, we found that protein kinase C (PKC) but not PKA phosphorylation influenced Claudin1 expression and cellular functions, as PKC inhibitor (Go 6983 and Staurosporine) or genetic silencing of PKC reduced Claudin1 expression and decreased the motility of KRIB and KHOS cells. Taken together, our study implied that delocalization of claudin-1 induced by PKC phosphorylation contributes to metastatic capacity of OS cells.

PKCδ-iPLA2-PGE2-PPARγ signaling cascade mediates TNF-α induced Claudin 1 expression in human lung carcinoma cells

Claudin 1 (CLDN1) is a critical component of tight junction adhesion complexes that maintains the structural integrity of epithelial cell layers. Dysregulation of CLDN1 is associated with the growth and metastasis of human lung adenocarcinoma. TNF-α treatment was previously shown to increase expression of CLDN1 that mediated lung cancer cell morphology changes and migration. This study aimed to elucidate the molecular mechanisms involved in TNF-α induced CLDN1 expression in human lung carcinoma A549 cells. Chemical inhibition or siRNA downregulation of Src, PI3K, Akt, MAPKs, NFκB, caspase and PKC demonstrated that PKC, specifically PKCδ, is required for TNF-α induced CLDN1 expression. Further investigation of the PKC pathway revealed that CLDN1 expression is enhanced by the downstream molecules iPLA2, PGE2, 15-keto PGE2 and PPARγ. Conversely, inhibition of these molecules decreased CLDN1 expression. Additionally, a wound-healing assay demonstrated that TNF-α stimulation, PKC activation, prostaglandin treatment or PPARγ activation enhanced cell migration. In conclusion, TNF-α induced CLDN1 expression is regulated by the PKCδ-iPLA2-PGE2-PPARγ signaling cascade in human lung carcinoma A549 cells.