SPINK5 inhibits esophageal squamous cell carcinoma metastasis via immune activity.

BACKGROUND: Esophageal squamous cell carcinoma (ESCC) is a predominant subtype of esophageal cancer with relatively high mortality worldwide. Serine peptidase inhibitor Kazal-type 5 (SPINK5) is reported to be downregulated in ESCC. However, its explicit role in ESCC remains further investigation. METHODS: The tumor tissues and adjacent non-cancerous tissues were obtained from 196 patients with ESCC for the determination of SPINK5 mRNA levels. Additionally, the relationship between SPINK5 mRNA levels and clinicopathological features of ESCC patients was explored. The effects of SPINK5 on the invasion and migration of ESCC cells were assessed using Transwell assays. Furthermore, SPINK5 mRNA and LEKTI protein were measured in ESCC cell lines after treatment with poly (I:C), lipopolysaccharide (LPS) or unmethylated CpG DNA. Moreover, the correlation between expression of SPINK5 and nuclear factor-kappa B (NF-κB) signaling pathway-related genes was analyzed in the TCGA-ESCC cohort, and the effects of SPINK5 on NF-κB transcription was analyzed using a luciferase reporter gene assay. Finally, the correlations between SPINK5 and infiltration of immune cells, immune scores, stromal scores and ESTIMATE (i.e., Estimation of STromal and Immune cells in MAlignant Tumor tissues using Expression data) scores were explored. RESULTS: SPINK5 mRNA levels were downregulated in tumor tissues, which was significantly correlated with higher lymph node metastases. Overexpressed SPINK5 inhibited cell invasion and migration in ESCC cell lines. Mechanistically, LPS-induced activation of Toll-like receptor 4 (TLR4) decreased SPINK5 mRNA and LEKTI in KYSE150 and KYSE70 cells. Spearman correlation analysis revealed that SPINK5 mRNA was significantly negatively correlated with a total of seven NF-κB signaling pathway-related genes in TCGA-ESCC patients. Moreover, downregulation of SPINK5 increased and upregulation of SPINK5 decreased the activity of the NF-κB promoter in HEK293T cells. Finally, immune cells infiltration analysis revealed that SPINK5 was significantly correlated with the infiltration of various immune cells, stromal scores, immune scores and ESTIMATE scores. CONCLUSIONS: SPINK5 plays critical roles in the TLR4/NF-κB pathway and immune cells infiltration, which might contribute to the ESCC metastasis. The findings of the present study may provide a promising biomarker for the diagnosis and treatment of esophageal squamous cell carcinoma.

Inhibition of the Tumor Suppressor Gene SPINK5 via EHMT2 Induces the Oral Squamous Cell Carcinoma Development.

Serine protease inhibitor Kazal-type 5 (SPINK5) has been revealed as a significant prognostic biomarker in oral squamous cell carcinoma (OSCC). However, there is little information regarding the detailed epigenetics mechanism underlying its dysregulation in OSCC. Using the Gene Expression Omnibus database, we identified SPINK5 as a significantly downregulated gene in OSCC tissues. Moreover, SPINK5 inhibited the malignant aggressiveness of HSC3 and squamous cell carcinomas (SCC)9 cells, whereas depletion of SPINK5 using shRNAs led to the opposite trend. The euchromatic histone lysine methyltransferase 2 (EHMT2) was found to bind to the SPINK5 promoter, and EHMT2 repressed the SPINK5 expression. SPINK5 reversed the stimulating effects of EHMT2 on the aggressiveness of HSC3 and SCC9 cells by impairing the Wnt/ß-catenin pathway. Wnt/ß-catenin inhibitor IWR-1 treatment reverted the malignant phenotype of OSCC cells in the presence of short hairpin RNA (sh)-SPINK5. Silencing of EHMT2 inhibited tumor growth and blocked the Wnt/ß-catenin signaling in OSCC, which was reversed by SPINK5 knockdown. Our study shows that SPINK5, mediated by the loss of EHMT2, can inhibit the development of OSCC by inhibiting Wnt/ß-catenin signaling and may serve as a treatment target for OSCC.

Lobelia chinensis Extract and Its Active Compound, Diosmetin, Improve Atopic Dermatitis by Reinforcing Skin Barrier Function through SPINK5/LEKTI Regulation.

The skin acts as a mechanical barrier that protects the body from the exterior environment, and skin barrier function is attributed to the stratum corneum (SC), which is composed of keratinocytes and skin lipids. Skin barrier homeostasis is maintained by a delicate balance between the differentiation and exfoliation of keratinocytes, and keratinocyte desquamation is regulated by members of the serine protease kalikrein (KLK) family and their endogenous inhibitor SPINK5/LEKTI (serine protease inhibitor Kazal type 5/lympho-epithelial Kazal-type-related inhibitor). Furthermore, SPINK5/LEKTI deficiency is involved in impaired skin barrier function caused by KLK over-activation. We sought to determine whether increased SPINK5/LEKTI expression ameliorates atopic dermatitis (AD) by strengthening skin barrier function using the ethanol extract of Lobelia chinensis (LCE) and its active compound, diosmetin, by treating human keratinocytes with UVB and using a DNCB-induced murine model of atopic dermatitis. LCE or diosmetin dose-dependently increased the transcriptional activation of SPINK5 promoter and prevented DNCB-induced skin barrier damage by modulating events downstream of SPINK5, that is, KLK, PAR2 (protease activated receptor 2), and TSLP (thymic stromal lymphopoietin). LCE or diosmetin normalized immune response in DNCB treated SKH-1 hairless mice as determined by reductions in serum immunoglobulin E and interleukin-4 levels and numbers of lesion-infiltrating mast cells. Our results suggest that LCE and diosmetin are good candidates for the treatment of skin barrier-disrupting diseases such as Netherton syndrome or AD, and that they do so by regulating SPINK5/LEKTI.

SPINK5 is a Tumor-Suppressor Gene Involved in the Progression of Nonsmall Cell Lung Carcinoma through Negatively Regulating PSIP1.

This study aimed to elucidate how SPINK5 affects the malignant phenotypes of NSCLC and the molecular mechanism. NSCLC and adjacent normal tissues were collected to detect the differential level of SPINK5. The influence of SPINK5 on pathological indicators of NSCLC was analyzed. Cellular functions of NSCLC cells overexpressing SPINK5 were assessed by CCK-8, EdU, and transwell assay. By confirming the downstream target of SPINK5, its molecular mechanism on regulating NSCLC was finally explored through rescue experiments. SPINK5 was lowly expressed in NSCLC tissues, and it predicted tumor staging and lymphatic metastasis. In vitro overexpression of SPINK5 declined proliferative and migratory rates in NSCLC cells. PSIP1 was verified as the target gene binding SPINK5, and they displayed a negative correlation in NSCLC tissues. Overexpression of PSIP1 was able to reverse the inhibited proliferative and migratory potentials in NSCLC cells overexpressing SPINK5. SPINK5 level has a close relation to tumor staging and lymphatic metastasis in NSCLC. It serves as a tumor-suppressor gene that inhibits proliferation and migration of NSCLC through negatively regulating PSIP1.

CEBPB knockdown sensitizes nasopharyngeal carcinoma cells to cisplatin by promoting the expression of serine protease inhibitor Kazal-type 5.

Serine protease inhibitor Kazal-type 5 (SPINK5) has been indicated to act as a prognostic predictor for patients with head and neck squamous cell carcinoma. However, its specific role in nasopharyngeal carcinoma (NPC), a malignancy that has a high propensity for chemoresistance, remains largely obscure. We, thus, sought to investigate the importance of SPINK5 expression in regulating chemoresistance in NPC. Differentially expressed genes in NPC were screened using the cancer genome atlas-head and neck squamous cell carcinoma database and microarray analysis. SPINK5 was downregulated in NPC tissues and cells. After SPINK5 upregulation, the cells treated with cisplatin showed reduced cell survival and the ability to migrate, invade and metastasize. Mechanistically, the transcription factors regulating SPINK5 were queried through the JASPAR website, followed by dual-luciferase and Chromatin immunoprecipitation assay validation. CCAAT enhancer-binding protein (CEBP) beta (CEBPB) bound to the SPINK5 promoter region in NPC cells. The silencing of CEBPB enhanced the expression of SPINK5. CEBPB overexpression reversed the inhibitory effects of cisplatin on NPC cell malignant phenotype in the presence of SPINK5 overexpression. In conclusion, CEBPB silencing promoted chemoresistance of NPC cells via activating SPINK5, signifying that targeting CEBPB was a new approach to enhance the chemotherapy efficacy in NPC.

Serine Protease Imbalance in the Small Airways and Development of Centrilobular Emphysema in Chronic Obstructive Pulmonary Disease.

Epithelial dysfunction in the small airways may cause the development of emphysema in chronic obstructive pulmonary disease. C/EBPα (CCAAT/enhancer binding protein-α), a transcription factor, is required for lung maturation during development, and is also important for lung homeostasis after birth, including the maintenance of serine protease/antiprotease balance in the bronchiolar epithelium. This study aimed to show the roles of C/EBPα in the distal airway during chronic cigarette smoke exposure in mice and in the small airways in smokers. In a model of chronic smoke exposure using epithelial cell-specific C/EBPα-knockout mice, significant pathological phenotypes, such as higher protease activity, impaired ciliated cell regeneration, epithelial cell barrier dysfunction via reduced zonula occludens-1 (Zo-1), and decreased alveolar attachments, were found in C/EBPα-knockout mice compared with control mice. We found that Spink5 (serine protease inhibitor kazal-type 5) gene (encoding lymphoepithelial Kazal-type-related inhibitor [LEKTI], an anti-serine protease) expression in the small airways is a key regulator of protease activity in this model. Finally, we showed that daily antiprotease treatment counteracted the phenotypes of C/EBPα-knockout mice. In human studies, CEBPA (CCAAT/enhancer binding protein-α) gene expression in the lung was downregulated in patients with emphysema, and six smokers with centrilobular emphysema (CLE) showed a significant reduction in LEKTI in the small airways compared with 22 smokers without CLE. LEKTI downregulation in the small airways was associated with disease development during murine small airway injury and CLE in humans, suggesting that LEKTI might be a key factor linking small airway injury to the development of emphysema.

TNF-α and IL-17A induce the expression of lympho-epithelial Kazal-type inhibitor in epidermal keratinocytes.

BACKGROUND: Serine proteases have important roles in skin barrier function and desquamation, and the aberrant expression or the dysfunction of serine proteases is associated with the pathogenesis of skin diseases. Serine protease activities are tightly regulated by serine proteases such as kallikrein-related peptidases (KLKs) and serine protease inhibitors such as lympho-epithelial Kazal-type related inhibitor (LEKTI). For a better understating of diseases' pathogenesis, the regulation mechanism of serine proteases and the inhibitors' expression in epidermal keratinocytes must be clarified. OBJECTIVES: To investigate the effects of the cytokines on the expression of LEKTI in epidermal keratinocytes. METHODS: Normal human epidermal keratinocytes (NHEKs) were stimulated with panels of inflammatory cytokines. The expression of serine protease inhibitors was analyzed using quantitative real-time PCR and ELISA. LEKTI expression in normal human skin and lesions from psoriasis or atopic dermatitis (AD) were analyzed by immunohistochemically and tape-stripping. Trypsin- and chymotrypsin-like serine protease activities in culture supernatants were measured by using specific substrates. RESULTS: TNF-α and IL-17A significantly induced the expression of LEKTI in NHEKs. The immunohistochemical and tape-stripping analysis revealed that psoriatic skin lesions had higher LEKTI expression compared to normal skin and AD lesions. Trypsin- and chymotrypsin-like protease activities in the culture media were upregulated 3-5 days later but attenuated 6-7 days later period by these cytokines. CONCLUSIONS: In epidermal keratinocytes, the Th1&Th17 cytokines TNF-α and IL-17A induce the expression of serine protease inhibitor LEKTI, and it might occur to suppress the increase in the serine protease activities under inflammation.

A novel tumor suppressor SPINK5 targets Wnt/ß-catenin signaling pathway in esophageal cancer.

Esophageal cancer is one of the most common tumor in the world, and the morbidity rate is as high as 100/100 000 in some parts of China. Therefore, it is important and urgent to explore the pathogenesis of esophageal cancer and find new therapeutic targets for esophageal cancer. In this study, we found that a novel tumor suppressor SPINK5 is significantly reduced in the development of esophageal cancer, and is closely related to the pathological differentiation and lymph node metastasis of esophageal cancer via bioinformatics analysis and esophageal cancer tissue array. Further studies have found that SPINK5 is closely related to Wnt/ß-catenin signaling pathway by bioinformatics analysis and western blot. In esophageal cancer cells, SPINK5 overexpression can inhibit Wnt/ß-catenin signaling pathway. Combined with LiCl or MG-132 treatment, SPINK5 can inhibit GSK3ß phosphorylation and promote ß-catenin protein degradation, thus inhibit Wnt/ß-catenin signaling pathway. In vivo study, SPINK5 overexpression can significantly inhibit the growth of esophageal cancer cells. Our study shows that SPINK5 can inhibit the proliferation, migration, and invasion of esophageal cancer cells by inhibiting Wnt/ß-catenin signaling pathway, and thus plays an important role in the development of esophageal cancer, and may serve as a treatment target of esophageal cancer.

Toll-like receptor signaling induces the expression of lympho-epithelial Kazal-type inhibitor in epidermal keratinocytes.

BACKGROUND: Lympho-epithelial Kazal-type inhibitor (LEKTI) tightly controls the activities of serine proteases such as kallikrein-related peptidase (KLK) 5 and KLK7 in the epidermis. LEKTI is known to be an essential molecule for the epidermal skin barrier, as demonstrated by SPINK5 nonsense mutation, which results in Netherton syndrome. Toll-like receptors (TLRs) recognize pathogen-associated molecular patterns or damage-associated molecular patterns and produce inflammatory cytokines, chemokines, and antimicrobial peptides. However, the effect of TLR signaling on the expression of LEKTI is not clear. OBJECTIVE: To investigate whether TLR signaling can affect expression of LEKTI in epidermal keratinocytes. METHODS: We stimulated a panel of TLR ligands and investigated the expression of LEKTI in normal human epidermal keratinocytes (NHEKs). We further measured trypsin or chymotrypsin-like serine protease activity in NHEK cultured media under stimulation with TLR3 ligand, poly (I:C). Immunostaining for LEKTI was performed using skin samples from skin infectious diseases. RESULTS: TLR1/2, 3, 5, and 2/6 ligands induced the expression of LEKTI in NHEKs. The trypsin or chymotrypsin-like serine protease activity in NHEKs was up-regulated with the stimulation of poly (I:C). The gene expressions of KLK6, KLK10, KLK11, and KLK13 were also increased by poly (I:C). An immunohistochemical analysis demonstrated that the expression of LEKTI was up-regulated in the lesions of varicella, pyoderma, and rosacea. CONCLUSIONS: TLR signaling induces the expression of LEKTI in epidermal keratinocytes, which might contribute to the control of aberrant serine protease activities in inflammatory skin diseases.

The antiprotease SPINK7 serves as an inhibitory checkpoint for esophageal epithelial inflammatory responses.

Loss of barrier integrity has an important role in eliciting type 2 immune responses, yet the molecular events that initiate and connect this with allergic inflammation remain unclear. We reveal an endogenous, homeostatic mechanism that controls barrier function and inflammatory responses in esophageal allergic inflammation. We show that a serine protease inhibitor, SPINK7 (serine peptidase inhibitor, kazal type 7), is part of the differentiation program of human esophageal epithelium and that SPINK7 depletion occurs in a human allergic, esophageal condition termed eosinophilic esophagitis. Experimental manipulation strategies reducing SPINK7 in an esophageal epithelial progenitor cell line and primary esophageal epithelial cells were sufficient to induce barrier dysfunction and transcriptional changes characterized by loss of cellular differentiation and altered gene expression known to stimulate allergic responses (for example, FLG and SPINK5). Epithelial silencing of SPINK7 promoted production of proinflammatory cytokines including thymic stromal lymphopoietin (TSLP). Loss of SPINK7 increased the activity of urokinase plasminogen-type activator (uPA), which in turn had the capacity to promote uPA receptor-dependent eosinophil activation. Treatment of epithelial cells with the broad-spectrum antiserine protease, α1 antitrypsin, reversed the pathologic features associated with SPINK7 silencing. The relevance of this pathway in vivo was supported by finding genetic epistasis between variants in TSLP and the uPA-encoding gene, PLAU We propose that the endogenous balance between SPINK7 and its target proteases is a key checkpoint in regulating mucosal differentiation, barrier function, and inflammatory responses and that protein replacement with antiproteases may be therapeutic for select allergic diseases.

Expressions of isopeptide bonds and corneodesmosin in middle ear cholesteatoma.

OBJECTIVE: Isopeptide bonds form cross-links between constituent proteins in the horny layer of the epidermis. Corneodesmosin (CDSN) is a major component of corneodesmosomes, which bind corneocytes together. Both play important roles in maintaining epidermal barrier functions. In the present study, we investigated the expressions of isopeptide bonds, CDSN, and related enzymes in middle ear cholesteatoma in comparison with the skin. DESIGN: Prospective case series of patients with middle ear cholesteatoma. SETTING: Tertiary medical institute. PARTICIPANTS: Cholesteatoma and normal postauricular skin were collected from patients with acquired middle ear cholesteatoma during tympanomastoidectomy. MAIN OUTCOME MEASURES: Expression of e-(g-glutamyl)lysine isopeptide bonds was examined by immunohistochemistry; Expressions of transglutaminase (TGase)1, TGase2, TGase3, and TGase5 by immunohistochemistry and quantitative RT-PCR (qRT-PCR); expression of CDSN by immunohistochemistry, qRT-PCR, and Western blot; and expressions of tissue kallikrein-related peptidase (KLK)5, KLK7, KLK14, and serine peptidase inhibitor Kazal type 5 (SPINK5) by qRT-PCR. RESULTS: TGase2 was higher (P=0.0046) and TGase5 was lower (P=0.0008) in cholesteatoma than in the postauricular skin. Immunoreactivity for isopeptide bonds was localized in the granular and horny layers, and was not different between the two tissues. Immunoreactivity for CDSN was localized in the granular layer, and was lower in cholesteatoma than in the skin (P=0.0090). Western blot and qRT-PCR confirmed that the expression of CDSN was lower in cholesteatoma than in the skin. Expressions of KLK5, KLK7, KLK14, or SPINK5 were not different between the two tissues. CONCLUSIONS: These results indicate that the production of CDSN is likely to be suppressed in cholesteatoma, which would account, at least in part, for the mechanical fragility and increased permeability of the cholesteatoma epithelium.