The Roles of Tricellular Tight Junction Protein Angulin-1/Lipolysis-Stimulated Lipoprotein Receptor (LSR) in Endometriosis and Endometrioid-Endometrial Carcinoma

Treatment with TNFα and lipolysis-stimulated lipoprotein receptor (LSR) antibody in the presence of HDAC inhibitors promotes apoptosis in human salivary duct adenocarcinoma

Lipolysis-stimulated lipoprotein receptor (LSR), a lipid metabolism-related factor localized in tricellular tight junctions (tTJs), plays an important role in maintaining the epithelial homeostasis. LSR is highly expressed in well-differentiated cancers, and its expression decreases during malignancy. The LSR antibody inhibits cell growth and promotes apoptosis in some cancers. Histone deacetylases (HDACs) are thought to play a crucial role in carcinogenesis, and HDAC inhibitors promote differentiation and prevent cell proliferation and migration in cancers. HDAC inhibitors together with TNFα also induce apoptosis via TNFα-related apoptosis-inducing ligand (TRAIL) in some cancers. In this study, we investigated the apoptosis signaling induced by an anti-LSR antibody in human salivary duct adenocarcinoma (SDC) cell line A253, compared to TRAIL-induced apoptosis. A253 cells were treated with human recombinant TNFα with or without HDAC inhibitor trichostatin A (TSA) and quisinostat (JNJ-26481585). Treatment using TNFα with HDAC inhibitors markedly induced apoptosis in A253 cells and the anti-TNFα antibody prevented the induced apoptosis. A253 cells were treated with an antibody against the extracellular N-terminal domain of human LSR (LSR-N-ab) with or without HDAC inhibitors. Treatment with HDAC inhibitors induced LSR expression in the membranes of A253 cells. Treatment using LSR-N-ab with HDAC inhibitors markedly promoted apoptosis in A253 cells. The tricellular signaling pathway JNK inhibitor SP600125 and Hippo pathway MST1/2 inhibitor XMU-MP-1 prevented the apoptosis induced by treatment using TNFα or LSR-N-ab with HDAC inhibitors. Our findings indicated that treatment with TNFα or LSR-N-ab with HDAC inhibitors might be useful in the therapy for human SDC by enhancing apoptosis.

The roles of tight junction protein cingulin in human endometrioid endometrial cancer

The bicellular tight junction molecule cingulin (CGN) binds to microtubules in centrosomes. Furthermore, CGN contributes to the tricellular tight junction (tTJ) proteins lipolysis-stimulated lipoprotein receptor (LSR) and tricellulin (TRIC). CGN as well as LSR decreased during the malignancy of endometrioid endometrial cancer (EEC). Although tTJ protein LSR is involved in the malignancy of some cancers, including EEC, the role of CGN is unknown. In this study, we investigated the roles of CGN with tTJ proteins in human EEC cells by using the CGN-overexpressing EEC cell line Sawano. In 2D cultures, CGN was colocalized with LSR and TRIC at tTJ or at γ-tubulin-positive centrosomes. In immunoprecipitation with CGN antibodies, CGN directly bound to LSR, TRIC, and β-tubulin. Knockdown of CGN by the siRNA decreased the epithelial barrier and enhanced cell proliferation, migration and invasion, as well as knockdown of LSR. In the Sawano cells cocultured with normal human endometrial stromal cells, knockdown of CGN decreased expression of LSR and TRIC via MAPK and AMPK pathways. In 2.5D cultures, knockdown of CGN induced the formation of abnormal cysts and increased the permeability of FD-4 to the lumen. In 2D and 2.5D cultures, treatment with β-estradiol with or without EGF or TGF-β decreased CGN expression and the epithelial permeability barrier and enhanced cell migration, and pretreatment with EW7197+AG1478, U0126 or an anti-IL-6 antibody prevented this. In conclusion, CGN, with tTJ proteins might suppress the malignancy of human EEC and its complex proteins are sensitive to estrogen and growth factors derived from stromal cells.

Di-(2-ethylhexyl) phthalate aggravates psoriasis-like skin lesions: In vitro and in vivo evaluation

Di-(2-ethylhexyl) phthalate (DEHP), which is a widely used phthalate (PAE), has recently received public attention owing to it causing health problems. The aim of this study was to elucidate the aggravating effects of DEHP on psoriasis and skin toxicity. Human keratinocyte (HaCaT) cells were treated with gradient concentrations of DEHP, and mice with imiquimod (IMQ)-induced psoriasiform dermatitis were hypodermically injected with 40 μg/kg/day of DEHP for seven consecutive days. The skin condition was assessed based on the psoriasis area and severity index score, which indicated the deterioration of IMQ-induced psoriasis-like skin lesions after DEHP exposure. To further analyze the effect of DEHP on psoriasis, the proliferation, inflammation, and tight junction (TJ) damage were examined, which correlated with the development and severity of psoriasis. The results showed that DEHP promoted proliferation both in vivo and in vitro, which manifested as epidermal thickening; an increase in cell viability; upregulation of Ki67, CDK2, cyclinD1, and proliferating cell nuclear antigen; and downregulation of p21. An excessive inflammatory response is an important factor that exacerbates psoriasis, and our results showed that DEHP can trigger the release of inflammatory cytokines as well as the infiltration of T cells. TJ disorders were found in mice and cells after DEHP treatment. Additionally, p38 mitogen-activated protein kinase (MAPK) was strongly activated during this process, which may have contributed to skin toxicity caused by DEHP. In conclusion, DEHP treatment promotes proliferation, inflammation, TJ disruption, and p38 MAPK activation in HaCaT cells and psoriasis-like skin lesions.

Expression patterns of claudins in cancer

Claudins are four-transmembrane proteins, which were found in tight junctions. They maintain cell barriers and regulate cell differentiation and proliferation. They are involved in maintaining cellular polarity and normal functions. Different claudins show different expression patterns. The expression level and localization of claudins are altered in various cancers. They promote or inhibit proliferation, invasion, and migration of cancer cells through multiple signaling pathways. Therefore, claudins may serve as diagnostic markers, novel therapeutic targets, and prognostic risk factors. The important roles of claudins in cancer aroused our great interest. In the present review, we provide a summary of insights into expression patterns of claudins in cancer, which is more comprehensive and provides new ideas for further research.

Research advances in endometriosis-related signaling pathways: A review

Endometriosis (EM) is characterized by the existence of endometrial mucosa outside the uterine cavity, which causesinfertility, persistent aches, and a decline in women's quality of life. Both hormone therapies and nonhormone therapies, such as NSAIDs, are ineffective, generic categories of EM drugs. Endometriosis is a benign gynecological condition, yet it shares a number of features with cancer cells, including immune evasion, survival, adhesion, invasion, and angiogenesis. Several endometriosis-related signaling pathways are comprehensively reviewed in this article, including E2, NF-κB, MAPK, ERK, PI3K/Akt/mTOR, YAP, Wnt/β-catenin, Rho/ROCK, TGF-β, VEGF, NO, iron, cytokines and chemokines. To find and develop novel medications for the treatment of EM, it is essential to implicitly determine the molecular pathways that are disordered during EM development. Additionally, research on the shared pathways between EM and tumors can provide hypotheses or suggestions for endometriosis therapeutic targets.

Selenomethionine protects against Escherichia coli-induced endometritis by inhibiting inflammation and necroptosis via regulating the PPAR-γ/NF-κB pathway

Endometritis, inflammation of the endometrium, is a major cause of subfertility in women. Selenomethionine (SeMet)is known to exert anti-inflammatory activity. We aimed to verify the protective roles of SeMet on Escherichia coli (E.coli)-induced endometritis. The extent of uterus damage was assessed by detecting histopathology and inflammatory mediators. The results revealed that SeMet significantly prevented E.coli-induced endometritis by attenuating uterine histopathology and inflammatory cytokine production. E.coli-induced MPO activity and MDA content were inhibited by SeMey. E.coli-induced ZO-1 and occludin were upregulated by SeMet. E.coli-induced necroptosis was also inhibited by SeMet. Additionally, E.coli-induced NF-κB activation was alleviated by SeMet. PPAR-γ expression was upregulated by SeMet. Notably, the protective effects of SeMet on endometritis were abolished by a PPAR-γ inhibitor. In conclusion, SeMet inhibits E.coli-induced endometritis by attenuating inflammation and necroptosis, which is mediated by the PPAR-γ/NF-κB signaling pathway.

Deciphering the role of predicted miRNAs of polyomaviruses in carcinogenesis

Human polyomaviruses are relatively common in the general population. Polyomaviruses maintain a persistent infection after initial infection in childhood, acting as an opportunistic pathogen in immunocompromised populations and their association has been linked to carcinogenesis. A comprehensive understanding of the underlying molecular mechanisms of carcinogenesis in consequence of polyomavirus infection remains elusive. However, the critical role of viral miRNAs and their potential targets in modifying the transcriptome profile of the host remains largely unknown. Polyomavirus-derived miRNAs have the potential to play a substantial role in carcinogenesis. Employing computational approaches, putative viral miRNAs along with their target genes have been predicted and possible roles of the targeted genes in many significant biological processes have been obtained. Polyomaviruses have been observed to target intracellular signal transduction pathways through miRNA-mediated epigenetic regulation, which may contribute to cancer development. In addition, BKPyV-infected human renal cell microarray data was coupled with predicted target genes and analysis of the downregulated genes indicated that viruses target multiple signaling pathways (e.g. MAPK signaling pathway, PI3K-Akt signaling pathway, PPAR signaling pathway) in the host as well as turning off several tumor suppression genes (e.g. FGGY, EPHX2, CACNA2D3, CDH16) through miRNA-induced mechanisms, assuring cell transformation. This study provides a conceptual framework for the underlying molecular mechanisms involved in the course of carcinogenesis upon polyomavirus infection.

LSR antibody promotes apoptosis and disrupts epithelial barriers via signal pathways in endometrial cancer

Lipolysis-stimulated lipoprotein receptor (LSR), a lipid metabolism-related factor localized in tricellular tight junctions (tTJs), plays an important role in maintaining the epithelial barrier. LSR is highly expressed in well-differentiated endometrial endometrioid carcinoma (EEC), and its expression decreases during malignancy. Angubindin-1, a novel LSR ligand peptide, regulates tTJs without cytotoxicity, enhances paracellular permeability, and regulates epithelial barrier via c-Jun N-terminal kinase (JNK)/cofilin. In this study, we investigated the immune-modulatory roles of an anti-LSR antibody in the treatment of EEC in vitro compared to those of angubindin-1. We prepared an antibody against the extracellular N-terminal domain of human LSR (LSR-N-ab) and angubindin-1. EEC cell-line Sawano cells in 2D and 2.5D cultures were treated with 100 μg/ml LSR-N-ab or 2.5 μg/ml angubindin-1 with or without protein tyrosine kinase 2β inhibitor PF431396 (PF43) and JNK inhibitor SP600125 (SP60) at 10 μM. Treatment with LSR-N-ab and angubindin-1 decreased LSR at the membranes of tTJs and the activity of phosphorylated LSR and phosphorylated cofilin in 2D culture. Treatment with LSR-N-ab and angubindin-1 decreased the epithelial barrier measured as TEER values in 2D culture and enhanced the epithelial permeability of FD-4 in 2.5D culture. Treatment with LSR-N-ab, but not angubindin-1, induced apoptosis in 2D culture. Pretreatment with PF43 and SP60 prevented all the changes induced by treatment with LSR-N-ab and angubindin-1. Treatment with LSR-N-ab and angubindin-1 enhanced the cell metabolism measured as the mitochondrial respiration levels in 2D culture. LSR-N-ab and angubindin-1 may be useful for therapy of human EEC via enhanced apoptosis or drug absorption.