In Vivo Vascular Permeability Detection in Mouse Submandibular Gland.

Saliva plays an important role in oral and overall health. The intact endothelial barrier function of blood vessels enables saliva secretion, whereas the endothelial barrier dysfunction is related to many salivary gland secretory disorders. The present protocol describes an in vivo paracellular permeability detection method to evaluate the function of endothelial tight junctions (TJs) in mouse submandibular glands (SMG). First, fluorescence-labeled dextrans with different molecular weights (4 kDa, 40 kDa, or 70 kDa) were injected into the angular veins of mice. Afterward, the unilateral SMG was dissected and fixed in the customized holder under a two-photon laser-scanning microscope, and then images were captured for blood vessels, acini, and ducts. Utilizing this method, the real-time dynamic leakage of the different-sized tracers from blood vessels into the basal sides of the acini and even across the acinar epithelia into the ducts was monitored to evaluate the alteration of the endothelial barrier function under physiological or pathophysiological conditions.

Interleukin-13 promotes cellular senescence through inducing mitochondrial dysfunction in IgG4-related sialadenitis.

Immunoglobulin G4-related sialadenitis (IgG4-RS) is an immune-mediated fibro-inflammatory disease and the pathogenesis is still not fully understood. The aim of this study was to explore the role and mechanism of interleukin-13 (IL-13) in the cellular senescence during the progress of IgG4-RS. We found that the expression of IL-13 and IL-13 receptor α1 (IL-13Rα1) as well as the number of senescent cells were significantly higher in the submandibular glands (SMGs) of IgG4-RS patients. IL-13 directly induced senescence as shown by the elevated activity of senescence-associated ß-galactosidase (SA-ß-gal), the decreased cell proliferation, and the upregulation of senescence markers (p53 and p16) and senescence-associated secretory phenotype (SASP) factors (IL-1ß and IL-6) in SMG-C6 cells. Mechanistically, IL-13 increased the level of phosphorylated signal transducer and activator of transcription 6 (p-STAT6) and mitochondrial-reactive oxygen species (mtROS), while decreased the mitochondrial membrane potential, ATP level, and the expression and activity of superoxide dismutase 2 (SOD2). Notably, the IL-13-induced cellular senescence and mitochondrial dysfunction could be inhibited by pretreatment with either STAT6 inhibitor AS1517499 or mitochondria-targeted ROS scavenger MitoTEMPO. Moreover, IL-13 increased the interaction between p-STAT6 and cAMP-response element binding protein (CREB)-binding protein (CBP) and decreased the transcriptional activity of CREB on SOD2. Taken together, our findings revealed a critical role of IL-13 in the induction of salivary gland epithelial cell senescence through the elevated mitochondrial oxidative stress in a STAT6-CREB-SOD2-dependent pathway in IgG4-RS.

Contribution of Interleukin-4-Induced Epithelial Cell Senescence to Glandular Fibrosis in IgG4-Related Sialadenitis.

OBJECTIVE: IgG4-related sialadenitis (IgG4-RS) is a chronic fibroinflammatory disease characterized by glandular fibrosis and hyposalivation. This study was undertaken to explore the role of cellular senescence in the pathogenesis of IgG4-RS-related fibrosis. METHODS: The expression of senescence markers and proinflammatory cytokines in the submandibular glands (SMGs) of IgG4-RS patients (n = 18) and controls (n = 14) was determined by proteomics, real-time polymerase chain reaction, Western blotting, and immunohistochemistry. After interleukin-4 (IL-4) treatment, high-throughput RNA sequencing was performed to identify the differentially expressed genes in SMG-C6 cells. A glandular fibrosis model was established by the intraglandular injection of IL-4 into mouse SMGs (n = 8 per group). RESULTS: Salivary acinar and ductal epithelial cells underwent senescence in IgG4-RS patients, as indicated by the elevated activity of senescence-associated ß-galactosidase, lipofuscin accumulation, enhanced expression of senescence markers (p53 and p16INK4A ), and up-regulation of senescence-associated secretory phenotype factors. Moreover, there was a significant increase in IL-4 levels in SMGs from IgG4-RS patients (P < 0.01), which positively correlated with p16INK4A expression and the fibrosis score. Incubation with IL-4 exacerbated salivary epithelial cell senescence by increasing the expression of p16INK4A through the reactive oxygen species (ROS)/p38 MAPK pathway. Supernatant collected from IL-4-induced senescent SMG-C6 cells enhanced fibroblast activation and matrix protein production (P < 0.05). Furthermore, injecting mice with IL-4 promoted fibrosis and senescence phenotypes in SMGs in vivo. CONCLUSION: The cellular senescence induced by IL-4 through the ROS/p38 MAPK-p16INK4A pathway promotes fibrogenesis in IgG4-RS. Our data suggest that cellular senescence could serve as a novel therapeutic target for treating IgG4-RS.

A pair of long intergenic non-coding RNA LINC00887 variants act antagonistically to control Carbonic Anhydrase IX transcription upon hypoxia in tongue squamous carcinoma progression.

BACKGROUND: Long noncoding RNAs (lncRNAs) are important regulators in tumor progression. However, their biological functions and underlying mechanisms in hypoxia adaptation remain largely unclear. RESULTS: Here, we established a correlation between a Chr3q29-derived lncRNA gene and tongue squamous carcinoma (TSCC) by genome-wide analyses. Using RACE, we determined that two novel variants of this lncRNA gene are generated in TSCC, namely LINC00887_TSCC_short (887S) and LINC00887_TSCC_long (887L). RNA-sequencing in 887S or 887L loss-of-function cells identified their common downstream target as Carbonic Anhydrase IX (CA9), a gene known to be upregulated by hypoxia during tumor progression. Mechanistically, our results showed that the hypoxia-augmented 887S and constitutively expressed 887L functioned in opposite directions on tumor progression through the common target CA9. Upon normoxia, 887S and 887L interacted. Upon hypoxia, the two variants were separated. Each RNA recognized and bound to their responsive DNA cis-acting elements on CA9 promoter: 887L activated CA9's transcription through recruiting HIF1α, while 887S suppressed CA9 through DNMT1-mediated DNA methylation. CONCLUSIONS: We provided hypoxia-permitted functions of two antagonistic lncRNA variants to fine control the hypoxia adaptation through CA9.

7SK Acts as an Anti-tumor Factor in Tongue Squamous Cell Carcinoma.

Increasing evidence has shown the mechanistic insights about non-coding RNA 7SK in controlling the transcription. However, the biological function and mechanism of 7SK in cancer are largely unclear. Here, we show that 7SK is down-regulated in human tongue squamous carcinoma (TSCC) and acts as a TSCC suppressor through multiple cell-based assays including a migration assay and a xenograft mouse model. The expression level of 7SK was negatively correlated with the size of tumors in the 73 in-house collected TSCC patients. Through combined analysis of 7SK knockdown of RNA-Seq and available published 7SK ChIRP-seq data, we identified 27 of 7SK-regulated genes that were involved in tumor regulation and whose upstream regulatory regions were bound by 7SK. Motif analysis showed that the regulatory sequences of these genes were enriched for transcription factors FOXJ3 and THRA, suggesting a potential involvement of FOXJ3 and THRA in 7SK-regulated genes. Interestingly, the augmented level of FOXJ3 in TSCC patients and previous reports on THRA in other cancers have suggested that these two factors may promote TSCC progression. In support of this idea, we found that 21 out of 27 aforementioned 7SK-associated genes were regulated by FOXJ3 and THRA, and 12 of them were oppositely regulated by 7SK and FOXJ3/THRA. We also found that FOXJ3 and THRA dramatically promoted migration in SCC15 cells. Collectively, we identified 7SK as an antitumor factor and suggested a potential involvement of FOXJ3 and THRA in 7SK-mediated TSCC progression.

Disruption of tight junction structure contributes to secretory dysfunction in IgG4-related sialadenitis.

IgG4-related sialadenitis (IgG4-RS) is a chronic fibro-inflammatory disease characterized by swelling of salivary glands and varying degrees of xerostomia. Tight junctions (TJs) play an essential role in maintaining secretory function by regulating the paracellular flow of ions and water. However, whether TJs are altered and contribute to the hyposecretion in IgG4-RS is not fully understood. Here, a total of 399 differentially expressed proteins were identified in IgG4-RS submandibular glands (SMGs) and enriched in the regulation of actin cytoskeleton and the salivary secretion. Real-time PCR results showed that the mRNA levels of claudin-3, -4, -6, -7, -8, -10, -12, occludin, and ZO-1 were significantly lower, whereas claudin-1 and -5 were higher in IgG4-RS SMGs. Immunohistochemical and immunofluorescence staining revealed that claudin-1, -3, -4, occludin, and ZO-1 were mainly distributed at apicolateral membranes in acini and ducts of SMGs from controls, whereas claudin-1 protein intensity at apicolateral membrane was elevated, while the staining of claudin-3, -4, and ZO-1 were reduced in IgG4-RS SMGs. Occludin was dispersed into cytoplasm of acini and ducts in SMGs of patients. Among them, claudin-3 and ZO-1 protein levels were positively correlated with saliva flow rate. Furthermore, the decreased fluorescence intensity of F-actin at peri-apicolateral membranes and the loss of ZO-1 staining at the same location were observed in acinar and ductal cells of IgG4-RS SMGs, which might be responsible for disorganization of TJ complex. Taken together, these findings indicate that the integrity of TJ complex of SMGs is impaired and might contribute to hyposalivation of IgG4-RS patients.

Clinicopathological and prognostic significance of homeobox transcript antisense RNA expression in various cancers: A meta-analysis.

BACKGROUND: Increased expression of the homeobox (HOX) transcript antisense RNA (HOTAIR) has been reported in multiple types of malignancies and enhances the proliferation and migration of cancer cells. However, the association between HOTAIR expression and tumor progression and prognosis remains controversial. We performed a meta-analysis to clarify the association between the expression of HOTAIR and the clinicopathological features and prognosis in different cancers. METHODS: A systematic search of the PubMed, Web of Science, EMBASE, and Ovid databases was conducted, up to September 2016, for eligible studies involving HOTAIR expression and malignancies. The odds ratios (ORs), hazard ratios (HRs), and corresponding 95% confidence intervals (CIs) were calculated using fixed- or random-effect models. Any publication bias was evaluated using Begg and Egger tests, and adjusted using the trim and fill method if a bias existed. RESULTS: A total of 4116 patients from 44 studies were included in our meta-analysis. The results showed that high HOTAIR expression was associated with an advanced clinical tumor stage (OR = 3.90, 95% CI = 3.02-5.03, P < .001), lymph node metastasis (OR = 3.11, 95% CI = 2.15-4.49, P < .001), poor differentiation of the tumor (OR = 1.56, 95% CI = 1.01-2.41, P = .03), and worse prognosis (HR = 2.16, 95% CI = 1.73-2.69, P < .001) in different cancer types. HOTAIR expression was more predictive in monitoring the clinical tumor stage of patients and there was no significant heterogeneity or publication bias found in the analysis. CONCLUSION: Our meta-analysis suggests that HOTAIR is positively correlated with tumor development and negatively correlated with clinical outcome. Thus, an increase in HOTAIR expression may be a potential biomarker for tumor progression and evaluation of prognosis.

Interleukin-17A promotes tongue squamous cell carcinoma metastasis through activating miR-23b/versican pathway.

Interleukin-17A (IL-17A), a proinflammatory cytokine mainly produced by T helper 17 cells, exerts protumor or antitumor effects in different cancer entities. However, the exact role of IL-17A in carcinogenesis and progression of tongue squamous cell carcinoma (TSCC) remains unclear. Here, we found that the levels of IL-17A in serum and tumor samples were significantly increased in TSCC patients and positively correlated with tumor metastasis and clinical stage. Besides, IL-17A enhanced cell migration and invasion in SCC15, a TSCC cell line. Furthermore, IL-17A inversely correlated with miR-23b expression in TSCC specimens. In vitro, NF-κB inhibited miR-23b transcription by directly binding to its promoter region. IL-17A downregulated miR-23b expression via activating NF-κB signaling pathway characterized by increasing p65 expression in the nuclear and elevating the levels of p-IKKα and p-IκBα. Overexpression of miR-23b inhibited, whereas knockdown of miR-23b promoted migration and invasion abilities of SCC15 cells. Moreover, extracellular matrix protein versican was proved to be the direct target of miR-23b through luciferase assay. IL-17A increased versican levels in vitro and knockdown of versican by siRNA inhibited SCC15 cell migration and invasion. Taken together, these results reveal a novel mechanism that IL-17A in TSCC microenvironment promotes the migration and invasion of TSCC cells through targeting miR-23b/versican pathway.