Matrix Metalloproteinases in Human Decidualized Endometrial Stromal Cells.

Cyclic changes, such as growth, decidualization, shedding, and regeneration, in the human endometrium are regulated by the reciprocal action of female hormones, such as estradiol (E2), and progesterone (P4). Matrix metalloproteases (MMPs) and tissue inhibitors of MMPs (TIMPs) control the invasion of extravillous trophoblast cells after implantation. Several MMPs and TIMPs function in the decidua and endometrial stromal cells (ESCs). Here, we aimed to systematically investigate the changes in MMPs and TIMPs associated with ESC decidualization. We evaluated the expression of 23 MMPs, four TIMPs, and four anti-sense non-coding RNAs from MMP loci. Primary ESC cultures treated with E2 + medroxyprogesterone acetate (MPA), a potent P4 receptor agonist, showed significant down-regulation of MMP3, MMP10, MMP11, MMP12, MMP20, and MMP27 in decidualized ESCs, as assessed by quantitative reverse transcription PCR. Further, MMP15 and MMP19 were significantly upregulated in decidualized ESCs. siRNA-mediated silencing of Heart and Neural Crest Derivatives Expressed 2 (HAND2), a master transcriptional regulator in ESC decidualization, significantly increased MMP15 expression in untreated human ESCs. These results collectively indicate the importance of MMP15 and MMP19 in ESC decidualization and highlight the role of HAND2 in repressing MMP15 transcription, thereby regulating decidualization.

GTSE1 promotes SNAIL1 degradation by facilitating its nuclear export in hepatocellular carcin oma cells.

Snail family transcriptional repressor 1 (SNAIL1) is a master inducer of the epithelial­to­mesenchymal transition (EMT) process, contributing to tumor metastasis and recurrence. Our previous study reported that G2 and S phase­expressed­1 (GTSE1) served a role in regulating SNAIL1 expression in hepatocellular carcinoma (HCC). However, the underlying mechanism remains unknown. Therefore, the present study aimed to reveal the regulatory mechanism of GTSE1 on SNAIL1 expression using in vitro assays performed in HCC cell models. It was demonstrated that endogenous SNAIL1 expression was downregulated and upregulated by GTSE1 overexpression or small interfering RNA­mediated knockdown, respectively. Via cycloheximide chase experiments, it was identified that GTSE1 overexpression increased the protein turnover of SNAIL1, while knockdown of GTSE1 reduced its degradation rate. Furthermore, it was demonstrated that GTSE1 overexpression induced the cytoplasmic expression of SNAIL1 using immunofluorescence and subcellular fractionation methods. The nuclear export inhibitor leptomycin B was able to decrease the cytoplasmic retention of SNAIL1 caused by GTSE1 overexpression. In addition, TGF­ßI treatment increased both the mRNA and protein expression levels of GTSE1, and decreased the protein expression level of SNAIL1 without affecting its mRNA transcription in Huh7 cells. It was also found that TGF­ß signaling could upregulate the transcription of GTSE1 expression by transactivating the Smad binding elements in the GTSE1 promoter. Moreover, the TGF­ßI­induced decrease in SNAIL1 protein expression was GTSE1­dependent in Huh7 cells. In conclusion, the current study provides a novel mechanism via which GTSE1 affects the stability of SNAIL1 by regulating its subcellular localization in HCC cells.

Phosphorylation regulates cullin-based ubiquitination in tumorigenesis.

Cullin-RING ligases (CRLs) recognize and interact with substrates for ubiquitination and degradation, and can be targeted for disease treatment when the abnormal expression of substrates involves pathologic processes. Phosphorylation, either of substrates or receptors of CRLs, can alter their interaction. Phosphorylation-dependent ubiquitination and proteasome degradation influence various cellular processes and can contribute to the occurrence of various diseases, most often tumorigenesis. These processes have the potential to be used for tumor intervention through the regulation of the activities of related kinases, along with the regulation of the stability of specific oncoproteins and tumor suppressors. This review describes the mechanisms and biological functions of crosstalk between phosphorylation and ubiquitination, and most importantly its influence on tumorigenesis, to provide new directions and strategies for tumor therapy.

SNAI1 interacts with HDAC1 to control TGF­ß2­induced epithelial­mesenchymal transition in human lens epithelial cells.

The opacity of the lens capsule after cataract surgery is caused by epithelial­to­mesenchymal transition (EMT) of lens epithelial cells. Snail family transcriptional repressor 1 (SNAI1) is a transcriptional repressor that recruits multiple chromatin enzymes including lysine­specific histone demethylase 1A, histone deacetylase (HDAC) 1/2, polycomb repressive complex 2, euchromatic histone lysine methyltransferase 2 and suppressor of variegation 3­9 homolog 1 to the E­cadherin promoter, thereby suppressing E­cadherin expression. However, the functional relationship between SNAI1 and HDAC in the induction of EMT in human lens epithelial cells (HLECs) is still unclear. Therefore, the objective of the present study was to explore the possible functional relationship between SNAI1 and HDAC1 in the induction of EMT in HLECs. In the present study, SNAI1 was found to be increased in HLECs during transforming growth factor­ß2 (TGF­ß2)­induced EMT. Knockdown of SNAI1 by siRNA reversed TGF­ß2­induced downregulation of E­cadherin and upregulation of α­Smooth Muscle Actin. Furthermore, SNAI1 was found to be associated with HDAC1 in the E­cadherin promoter in TGF­ß2­treated HLECs. Inhibition of HDAC by trichostatin A and suberoylanilide hydroxamic acid could prevent TGF­ß2­induced EMT in HLECs. Collectively, SNAI1 interacted with HDAC1 to repress E­cadherin in the TGF­ß2­induced EMT in HLECs, suggesting that HDAC inhibitors may have potential therapeutic value for the prevention of EMT in HLECs.

MicroRNA-153 suppresses human laryngeal squamous cell carcinoma migration and invasion by targeting the SNAI1 gene.

Human laryngeal squamous cell carcinoma (LSCC) is a malignant cancer type. Epithelial-mesenchymal transition marker Snail family transcriptional repressor 1 (SNAI1) is associated with the occurrence, development, invasion and metastasis of numerous tumor types, such as lung, liver and ovarian cancer. Previous studies have indicated that microRNA-153 (miR-153) may serve as a novel tumor suppressor, which is involved in tumor metastasis; however, the role and clinical significance of miR-153 in LSCC are not fully understood. The aim of the present study was to determine the role of miR-153 in the growth and aggressiveness of LSCC cells. Bioinformatics prediction method, western blot analysis, Matrigel invasion assay and immunofluorescence were used to analyze whether SNAI1 can be regulated and controlled by miR-153 in LSCC cells. An inverse association between miR-153 and SNAI1 was observed in LSCC tissues. It was demonstrated that SNAI1 is a direct target of miR-153 in LSCC. In addition, the results indicated that miR-153 knockdown inhibited PCI-13 cell migration and invasion by targeting SNAI1, which may be a potential marker that can reflect the degree of malignancy in patients with LSCC. Furthermore, miR-153 knockdown decreased Twist family BHLH transcription factor 1 and metastasis-associated 1 family member 3 expression in LSCC cells. In conclusion, these data indicated that miR-153 regulates LSCC migration via the targeting of SNAI1 gene, which may be a potential predictor for patients with LSCC.

MicroRNA-124 suppresses growth and aggressiveness of osteosarcoma and inhibits TGF-ß-mediated AKT/GSK-3ß/SNAIL-1 signaling.

Osteosarcoma is one of the most common malignant tumors in adolescent populations and the prognosis remains incompletely understand. Previous reports have demonstrated that microRNA­124 (miR­124) has inhibitory effects on various human malignancies and is associated with tumor progression. However, the clinical significance and potential mechanisms of miR­124 in the progression of osteosarcoma is not clearly understood. In this study, the potential molecular mechanism of miR­124 in osteosarcoma tumorigenesis, growth and aggressiveness was investigated. The growth, proliferation, apoptosis, migration and invasion of osteosarcoma cells were investigated following miR­124 transfection were determined by colony formation assay, western blotting, immunofluorescence, migration/invasion assays and reverse transcription­quantitative polymerase chain reaction. In vivo anti­cancer effects of miR­124 were analyzed by a tumor growth assay, immunohistochemistry and survival rate observations. The results demonstrated that miR­124 transfection significantly decreased integrin expression in osteosarcoma cells, and further inhibited growth, proliferation, migration and invasion of osteosarcoma cells. Flow cytometry assays indicated that miR­124 transfection attenuated apoptosis resistance of osteosarcoma to tunicamycin, potentially via the downregulation of P53 and Bcl­2 apoptosis regulator expression. Mechanistic assays demonstrated that miR­124 transfection suppressed TGF­ß expression in osteosarcoma. An animal study revealed that tumor growth was reduced in tumor cells transfected with miR­124 compared with control cells, and the survival rate was prolonged in mice with miR­124 transfected xenografts compared with control tumors. In conclusion, these results indicate that miR­124 transection inhibits the growth and aggressive of osteosarcoma, potentially via suppression of TGF­ß­mediated AKT/GSK­3ß/snail family transcriptional repressor 1 (SNAIL­1) signaling, suggesting miR­124 may be a potential anti­cancer agent/target for osteosarcoma therapy.