Intracellular claudin-1 at the invasive front of tongue squamous cell carcinoma is associated with lymph node metastasis

Capsaicin combined with cisplatin inhibits TGF-β1-induced EMT and TSCC cells migration via the Claudin-1/PI3K/AKT/mTOR signaling pathway

Tongue squamous cell carcinoma (TSCC) is one of the most common malignant tumors among oral cancers, and its treatment is based on radio-chemotherapy and surgery, which always produces more serious side effects and sequelae. Traditional medicine can compensate for the shortcomings of modern medical treatments and play a better therapeutic role. Currently, active ingredients derived from plants are attracting the attention of researchers and clinical professionals. We examined capsaicin (CAP), an active ingredient isolated from Capsicum annuum (family Solanaceae), and explored the effect of CAP combined with cisplatin (DDP) on epithelial-mesenchymal transition (EMT) and TSCC cells migration. Our results demonstrated that Transforming growth factor-β1(TGF-β1) induced EMT and promoted cell migration in TSCC cells. CAP combined with DDP inhibits non-TGF-β1-induced or TGF-β1-induced EMT and migration. Mechanistically, the inhibition of non-TGF-β1-induced EMT and migration by CAP combined with DDP was mediated by the AMPK/mTOR pathway, whereas TGF-β1-induced EMT and migration were regulated by the Claudin-1/PI3K/AKT/mTOR pathway. A nude lung metastasis mouse model was established for in vivo validation. These results support our hypothesis that the combination of CAP and DDP inhibits TSCC metastasis. These data set the stage for further studies aimed at validating CAP as an effective active ingredient for enhancing chemotherapy efficacy and reducing the dosage and toxicity of chemotherapeutic drugs, ultimately paving the way for translational research and clinical trials for TSCC eradication.

The activation of adenosine monophosphate-activated protein kinase inhibits the migration of tongue squamous cell carcinoma cells by targeting Claudin-1 via epithelial-mesenchymal transition

BACKGROUND

The role of Claudin-1 in tongue squamous cell carcinoma (TSCC) metastasis needs further clarification, particularly its impact on cell migration. Herein, our study aims to investigate the role of Claudin-1 in TSCC cell migration and its underlying mechanisms.

METHODS

36 TSCC tissue samples underwent immunohistochemical staining for Claudin-1. Western blotting and immunofluorescence analyses were conducted to evaluate Claudin-1 expression and distribution in TSCC cells. Claudin-1 knockdown cell lines were established using short hairpin RNA transfection. Migration effects were assessed through wound healing assays. Furthermore, the expression of EMT-associated molecules was measured via western blotting.

RESULTS

Claudin-1 expression decreased as TSCC malignancy increased. Adenosine monophosphate-activated protein kinase (AMPK) activation led to increased Claudin-1 expression and membrane translocation, inhibiting TSCC cell migration and epithelial-mesenchymal transition (EMT). Conversely, Claudin-1 knockdown reversed these inhibitory effects on migration and EMT caused by AMPK activation.

CONCLUSIONS

Our results indicated that AMPK activation suppresses TSCC cell migration by targeting Claudin-1 and EMT pathways.

Role of Stromal Fibroblast-Induced WNT7A Associated with Cancer Cell Migration Through the AKT/CLDN1 Signaling Axis in Oral Squamous Cell Carcinoma

Wnt signaling plays a crucial role in the progression of various cancers, including oral squamous cell carcinoma (OSCC). However, the tumor microenvironment (TME) regulating Wnt signaling has not yet been fully elucidated. In this study, we investigated whether cancer-associated fibroblasts (CAFs), the primary components of the TME, activate Wnt signaling and promote tumor progression in OSCC. We conducted a Transwell coculture assay using human OSCC cell lines and normal human dermal fibroblasts (NHDFs). NHDFs stimulated WNT7A expression in several OSCC cell lines, especially HO-1-N-1 and HSC-5. An immunohistochemical study using 122 human OSCC samples indicated that high WNT7A expression in tumor cells was significantly associated with invasion depth and poor prognosis. Moreover, WNT7A expression in OSCC cells was positively correlated with α-smooth muscle actin expression in CAFs. WNT7A knockdown in OSCC cells demonstrated that OSCC cells cocultured with NHDFs significantly promoted tumor cell migration and invasion, which was dependent on WNT7A expression in OSCC cells. We also isolated HSC-5 cells from the coculture and conducted microarray analysis to investigate the factors that promote tumor progression induced by WNT7A. Among the various differentially expressed genes, we identified a downregulated gene encoding CLDN1 and confirmed that WNT7A negatively regulated CLDN1 expression in OSCC cells and CLDN1 knockdown in OSCC cells promoted their migration. Phosphokinase array analysis showed that WNT7A activates protein kinase B (AKT) phosphorylation. Activating AKT signaling using the SC79 agonist induced CLDN1 downregulation in OSCC cells. In the coculture assay, the AKT inhibitor MK2206 significantly recovered CLDN1 expression downregulated by WNT7A, resulting in OSCC cell migration suppression. These results suggest that CAFs stimulate OSCC cells to produce WNT7A, following CLDN1 expression downregulation by activating AKT signaling, promoting cancer cell migration. These findings highlight the importance of molecular therapies targeting the TME in OSCC.

Aberrant Expression of Claudins in Head and Neck Carcinomas and Their Prognostic and Therapeutic Value: A Narrative Review

Head and neck carcinomas have been associated with poor prognosis. Recent studies have highlighted the role of claudins' expression in tumors throughout the body, and their prognostic and therapeutic role. Understanding the role of claudins and how their expression affects the progression of carcinomas in the head and neck region may allow for advances in the prognosis and management of this type of cancer. Several studies have highlighted the aberrant expression of the proteins in carcinomas in this region. Specifically, the overexpression of claudin-1 and downregulation of claudins-4, -7, and -17 have been linked with poor survival in oral squamous cell carcinoma patients. In laryngeal squamous cell carcinoma, increased levels of claudins-1 and reduced levels of claudins-3, -8, and -11 have been linked with poor outcomes. Targeting these proteins has shown promising outcomes as therapeutic in preclinical studies. However, studies remain extremely limited in nasal and hypopharyngeal carcinomas. In this review, we survey the available literature describing the aberrant expression of various claudins in carcinomas in this region, while highlighting their potential prognostic and therapeutic value. Then, we describe some molecular mechanisms involved in the aberrant expression of claudins and how they can be utilized as therapeutic targets.

Zengshengping improves lung cancer by regulating the intestinal barrier and intestinal microbiota

Lung cancer is a common malignant tumor in clinical practice, and its morbidity and mortality are in the forefront of malignant tumors. Radiotherapy, chemotherapy, and surgical treatment play an important role in the treatment of lung cancer, however, radiotherapy has many complications and even causes partial loss of function, the recurrence rate after surgical resection is high, and the toxic and side effects of chemotherapy drugs are strong. Traditional Chinese medicine has played a huge role in the prognosis and improvement of lung cancer, among them, Zengshengping (ZSP) has the effect of preventing and treating lung cancer. Based on the “gut-lung axis” and from the perspective of “treating the lung from the intestine”, the purpose of this study was to research the effect of Zengshengping on the intestinal physical, biological, and immune barriers, and explore its role in the prevention and treatment of lung cancer. The Lewis lung cancer and urethane-induced lung cancer models were established in C57BL/6 mice. The tumor, spleen, and thymus were weighed, and the inhibition rate, splenic and thymus indexes analyzed. Inflammatory factors and immunological indexes were detected by enzyme-linked immunosorbent assay. Collecting lung and colon tissues, hematoxylin and eosin staining was performed on lung, colon tissues to observe histopathological damage. Immunohistochemistry and Western blotting were carried out to detect tight junction protein expression in colon tissues and expression of Ki67 and p53 proteins in tumor tissues. Finally, the feces of mice were collected to investigate the changes in intestinal microbiota using 16SrDNA high-throughput sequencing technology. ZSP significantly reduced tumor weight and increased the splenic and thymus indexes. It decreased expression of Ki67 protein and increased expression of p53 protein. Compared with Model group, ZSP group reduced the serum levels of interleukin (IL)-1β, IL-6, tumor necrosis factor α (TNF-α), and ZSP group increased the concentration of secretory immunoglobulin A (sIgA) in the colon and the bronchoalveolar lavage fluid (BALF). ZSPH significantly increased the level of tight junction proteins such as ZO-1, Occludin and Claudin-1. Model group significantly reduced the relative abundance of Akkermansia (p < 0.05) and significantly promoted the amount of norank_f_Muribaculaceae, norank_f_Lachnospiraceae (p < 0.05) compared with that in the Normal group. However, ZSP groups increased in probiotic strains (Akkermansia) and decreased in pathogens (norank_f_Muribaculaceae, norank_f_Lachnospiraceae). Compared with the urethane-induced lung cancer mice, the results showed that ZSP significantly increased the diversity and richness of the intestinal microbiota in the Lewis lung cancer mice. ZSP played an important role in the prevention and treatment of lung cancer by enhancing immunity, protecting the intestinal mucosa and regulating the intestinal microbiota.

Differential Expression of Claudin 1 and 4 in Basal Cell Carcinoma of the Skin

Basal cell carcinoma (BCC) is the most common human malignancy. The biological behavior of this entity is remarkably indolent. Claudin plays an important role in tight junctions, regulating paracellular passage of variable substance including growth factors and maintaining the polarity of epithelia. Up- or downregulated claudin expression has been reported in many cancers. Nevertheless, claudin expression in BCC of the skin remains unclear. We therefore examined the status of claudin 1 and 4 expressions in BCC and adjacent normal skin by immunohistochemistry (IHC). Our IHC results demonstrated high claudin 1 expression and low claudin 4 expression in 33 of 34 lower-grade BCCs. In lower-grade BCC, claudin 1 was increased and claudin 4 was decreased compared with the normal skin. Claudin 1 was inclined to be highly expressed in the membrane and cytoplasm of tumour cells in the periphery of tumour nest. Conversely, almost all lower-grade BCCs (33/34) and one of two higher-grade BCC lacked or showed focal positivity for claudin 4. These results imply that the expression pattern is characteristics of lower-risk BCC. Interestingly, one of the two higher-grade BCCs demonstrated the converse expression patterns of claudins, with decreased claudin 1 and increased claudin 4. The combination of immunohistochemical claudin 1 and 4 expression may offer a useful ancillary tool for the pathological diagnosis of BCC. Furthermore, membranous and intracellular claudins may present future therapeutic targets for uncontrollable BCC.

Loss of intercellular bridges in the depth of invasion measurement area is a novel negative prognostic factor for oral squamous cell carcinoma: A retrospective study

OBJECTIVE

This study aimed to evaluate intercellular bridges in the depth of invasion (DOI) measurement area as prognostic factors in oral squamous cell carcinoma (OSCC).

STUDY DESIGN

The mode of invasion was determined based on the Yamamoto-Kohama classification system by observing the hematoxylin-eosin-stained whole-slide images of specimens obtained from 78 patients with OSCC, and the clinicopathologic features were characterized. The presence of intercellular bridges was analyzed in 46 patients with Yamamoto-Kohama classification grade ≥3 whose DOI was measured by dividing the measurement area into 3 parts: the surface, center, and front of the tumor.

RESULTS

Univariate analyses identified lymph node metastasis, loss of intercellular bridges in the DOI measurement area, DOI of ≥4500 µm, and pattern of invasion 4C-4D as negative prognostic factors. Multivariate analyses revealed that lymph node metastasis and the loss of intercellular bridges in the entire area were independent factors, with hazard ratios of 9.34 (95% confidence interval, 2.09-42.03; P = .003) and 3.64 (95% confidence interval, 1.10-11.99; P = .045), respectively.

CONCLUSIONS

Loss of intercellular bridges in the DOI measurement area is a negative prognostic factor for OSCC and may be useful in selecting treatment.

Tight junction protein CLDN17 serves as a tumor suppressor to reduce the invasion and migration of oral cancer cells by inhibiting epithelial-mesenchymal transition

OBJECTIVE

To investigate claudin-17 (CLDN17) expression in oral cancer and its effect on epithelial-mesenchymal transition (EMT), invasion and migration in oral cancer cells.

METHODS

The GEO2R tool was used to analyze gene expression in two microarray datasets (GSE74530 and GSE146483) derived from the Gene Expression Omnibus (GEO) database. Gene Expression Profiling Interactive Analysis (GEPIA) verified CLDN17 expression in head and neck squamous cell carcinoma (HNSC) patients. Moreover, oral cancer cells were transfected with CLDN17 overexpression plasmid or CLDN17 shRNA to evaluate cell invasion and migration. Gene and protein expression was detected by qRT-PCR, immunohistochemistry and western blotting.

RESULTS

CLDN17 was one of the top 200 differentially expressed genes in the GSE74530 and GSE146483 datasets and was downregulated in oral cancer. CLDN17 expression was higher in HNSC tissues, and it was related to TNM staging. In HNSC tumors, CLDN17 expression was positively correlated with CDH1 but negatively related to VIM, SNAIL1, SNAIL2, and TWIST1. Meanwhile, we found that CLDN17 expression was lower in oral cancer tissues; it declined with higher T status, N status, M status and staging, lower differentiation grade, and a worse prognosis. Upregulation of CLDN17 inhibited the invasion and migration of oral cancer cells, with elevated CDH1 and reduced VIM, SNAIL1, SNAIL2, and TWIST1, while CLDN17 downregulation had the opposite effects.

CONCLUSION

CLDN17 may serve as a tumor suppressor in oral cancer since it could reduce the invasion and migration of cells by inhibiting the EMT process, thus becoming a potential therapeutic target in oral cancer.

Long non-coding RNA VPS9D1-AS1 promotes growth of colon adenocarcinoma by sponging miR-1301-3p and CLDN1

Colon adenocarcinoma is a frequent malignancy among all colon cancer types. Long non-coding RNAs (lncRNAs) are involved in the progression of colon adenocarcinoma. This study aimed to uncover the molecular mechanism of VPS9D1-AS1 in regulating colon adenocarcinoma development. Quantitative reverse transcription-polymerase chain reaction (RT-qPCR) revealed that VPS9D1-AS1 expression was markedly upregulated in colon adenocarcinoma tissues and cell lines. Cell functional experiments showed that knockdown of VPS9D1-AS1 repressed the growth and invasion of colon adenocarcinoma cells but upregulated cell apoptosis. In addition, we confirmed the interaction of VPS9D1-AS1-miR-1301-3p-CLDN1 using a luciferase assay. Downregulation of miR-1301-3p promoted the progression of colon adenocarcinoma cells. In conclusion, VPS9D1-AS1 facilitated cell growth and suppressed apoptosis of colon adenocarcinoma cells by sponging miR-1301-3p and upregulating CLDN1, which may be effective therapeutic strategies for patients with colon adenocarcinoma.

Context-Dependent Roles of Claudins in Tumorigenesis

The barrier and fence functions of the claudin protein family are fundamental to tissue integrity and human health. Increasing evidence has linked claudins to signal transduction and tumorigenesis. The expression of claudins is frequently dysregulated in the context of neoplastic transformation. Studies have uncovered that claudins engage in nearly all aspects of tumor biology and steps of tumor development, suggesting their promise as targets for treatment or biomarkers for diagnosis and prognosis. However, claudins can be either tumor promoters or tumor suppressors depending on the context, which emphasizes the importance of taking various factors, including organ type, environmental context and genetic confounders, into account when studying the biological functions and targeting of claudins in cancer. This review discusses the complicated roles and intrinsic and extrinsic determinants of the context-specific effects of claudins in cancer.

CLDN15 is a novel diagnostic marker for malignant pleural mesothelioma

Malignant mesothelioma is a cancer with a poor survival rate. It is difficult to diagnose mesotheliomas because they show a variety of histological patterns similar to those of various other cancers. However, since currently used positive markers for mesotheliomas may show false positives or false negatives, a novel mesothelial positive marker is required. In the present study, we screened 25 claudins and found that claudin-15 is expressed in the mesothelial cells. We made new rat anti-human claudin-15 (CLDN15) monoclonal antibodies that selectively recognize CLDN15, and investigated whether CLDN15 is a good positive marker for malignant pleural mesotheliomas (MPMs) using MPM tissue samples by immunohistochemistry and semi-quantification of the expression level using an immunoreactive score (IRS) method. Of 42 MPM samples, 83% were positive for CLDN15. The positive ratio was equal to or greater than other positive markers for MPMs including calretinin (81%), WT-1 (50%), and D2-40 (81%). In 50 lung adenocarcinoma sections, four cases were positive for CLDN15 and the specificity (92%) was comparable with other markers (90–100%). Notably, CLDN15 was rarely detected in 24 non-mesothelial tumors in the tissue microarray (12/327 cases). In conclusion, CLDN15 can be used in the clinical setting as a positive marker for MPM diagnosis.

Reduced Claudin-12 Expression Predicts Poor Prognosis in Cervical Cancer

Background: Within the claudin (CLDN) family, CLDN12 mRNA expression is altered in various types of cancer, but its clinicopathological relevance has yet to be established due to the absence of specific antibodies (Abs) with broad applications. Methods: We generated a monoclonal Ab (mAb) against human/mouse CLDN12 and verified its specificity. By performing immunohistochemical staining and semiquantification, we evaluated the relationship between CLDN12 expression and clinicopathological parameters in tissues from 138 cases of cervical cancer. Results: Western blot and immunohistochemical analyses revealed that the established mAb selectively recognized the CLDN12 protein. Twenty six of the 138 cases (18.8%) showed low CLDN12 expression, and the disease-specific survival (DSS) and recurrence-free survival rates were significantly decreased compared with those in the high CLDN12 expression group. We also demonstrated, via univariable and multivariable analyses, that the low CLDN12 expression represents a significant prognostic factor for the DSS of cervical cancer patients (HR 3.412, p = 0.002 and HR 2.615, p = 0.029, respectively). Conclusions: It can be concluded that a reduced CLDN12 expression predicts a poor outcome for cervical cancer. The novel anti-CLDN12 mAb could be a valuable tool to evaluate the biological relevance of the CLDN12 expression in diverse cancer types and other diseases.

Intracellular claudin-1 at the invasive front of tongue squamous cell carcinoma is associated with lymph node metastasis

Claudins are the major component of tight junctions, which form a primary barrier to paracellular diffusion and maintain cell polarity in normal epithelia and endothelia. In cancer cells, claudins play additional roles besides serving as components of the tight junctions, and participate in anoikis or invasion. Among the claudin family proteins, claudin‐1 has the most promising potential, both diagnostically and prognostically, in many types of cancers, including oral, gastric, liver, and colon cancers. However, conflicting results have been reported in relation to the degree of claudin‐1 expression and the prognosis, suggesting that the expression level of claudin‐1 alone is not sufficient to analyze the relationship between claudin‐1 and cancer progression. As endocytic trafficking of claudin‐1 has been reported in several epithelial cell types in vitro, we aimed to determine whether intracellular localization of claudin‐1 is the missing aspect between claudin‐1 and cancer. We investigated the expression of claudin‐1 in 83 tongue squamous cell carcinoma (TSCC) pathological specimens. Although the expression level of claudin‐1 based on immunohistochemistry was not associated with TSCC progression, within the high claudin‐1 expression group, the incidence of intracellular localization of claudin‐1 was correlated with cervical lymph node metastasis. In an in vitro experiment, claudin‐1 was constitutively internalized in TSCC‐derived cells. Motility of TSCC‐derived cells was increased by deficiency of claudin‐1, suggesting that the decrease in cell‐surface claudin‐1 promoted the cell migration. Therefore, intracellular localization of claudin‐1 at the invasion front may represent a promising diagnostic marker of TSCC.