PADI4 promotes epithelial-mesenchymal transition(EMT) in gastric cancer via the upregulation of interleukin 8.

BACKGROUND: Gastric cancer (GC) is one of the deadliest tumours due to its ability to metastasize. The Epithelial-to-mesenchymal transition plays a crucial role in promoting the GC metastasis, which increases the migration and metastasis of tumour cells. Peptidyl arginine deiminase IV (PADI4) is a susceptibility gene for gastric carcinoma. The aim of this study was to evaluate the functional roles of PADI4 in gastric cancer. METHODS: The expression of PADI4 was examined by qRT-PCR, western blot and immunohistochemistry. In addition, the functional roles of PADI4 were explored by over-expression PADI4 plasmids in gastric cancer cells. RESULTS: We found that the expression of PADI4 was up-regulated in GC. PADI4 overexpression in GC cells increased the proliferation, migration, metastasis, clone forming ability, and tumorigenic ability, but reduced the apoptosis ability. The Multi-Analyte ELISArray Kit results showed that interleukin 8 (IL-8) is upregulated in PADI4-overexpressing gastric cells. Using short interfering RNA (siRNA) to silence the expression of IL-8, we demonstrated that IL-8 silencing significantly inhibited the increased migratory capacity in PADI4-overexpressing GC cells. CONCLUSIONS: Our data suggest that PADI4 accelerate metastasis by promoting IL-8 expression in gastric cancer cells, indicating that it is a new PADI4/IL-8 signalling pathway in metastatic GC.

ARHGEF10L expression regulates cell proliferation and migration in gastric tumorigenesis.

We recently reported that Rho guanine nucleotide exchange factor 10-like protein (ARHGEF10L) activated Rho GTPases as guanine nucleotide exchange factor to stimulate liver tumorigenesis. The present study continued to explore the effect of ARHGEF10L on the tumorigenic process of gastric cancer. This study detected increased expression of ARHGEF10L in GC tissues compared to peritumoral tissue samples. SGC7901 cells with ARHGEF10L overexpression showed increased cell proliferation, cell migration, and tube-like structure formation abilities, as well as increased expression of GTP-RhoA, ROCK1, and phospho-Ezrin/Radixin/Moesin. ARHGEF10L overexpression downregulated the expression of E-cadherin and upregulated the expression of N-cadherin and Slug, indicating an activation of EMT in the transfected cells. RNA-sequencing assay detected an increased expression of Heat shock 70 kDa protein 6 in the SGC7901 cells overexpressing ARHGEF10L. The above results suggest that ARHGEF10L expression can stimulate gastric tumorigenesis by prompting RhoA-ROCK1-phospho-ERM signaling, inducing EMT and increasing HSPA6 expression.

B-cell specific Moloney leukemia virus insert site 1 and peptidyl arginine deiminase IV positively regulate carcinogenesis and progression of esophageal squamous cell carcinoma.

High expression of B-cell specific Moloney leukemia virus insert site 1 (Bmi-1) and peptidyl arginine deiminase IV (PADI4) is associated with esophageal carcinoma. However, few studies have investigated the association between the Bmi-1 and PADI4 genes. The aim of the present study was to evaluate the expression of Bmi-1 and PADI4 and identify the association between the Bmi-1 and PADI4 genes in esophageal squamous cell carcinoma (ESCC) tissues. Bmi-1 and PADI4 gene expression levels were measured using immunohistochemistry, western blotting and reverse transcription-quantitative polymerase chain reaction in ESCC tissues from 86 patients who had not received pre-operative chemoradiation. The results revealed that the Bmi-1 and PADI4 genes had increased expression in carcinoma tissues compared with pericarcinous tissue (P<0.05). Bmi-1 gene expression was revealed to be associated with differentiation degree, clinical stage and lymph node metastasis (P<0.05), but had no association with gender, age or depth of invasion (P>0.05). The expression of PADI4 was associated with clinical stage, depth of invasion and lymph node metastasis (P<0.05), but was not associated with gender, age or differentiation degree (P>0.05). In addition, there was a positive association between Bmi-1 and PADI4 gene expression in ESCC (P<0.05). These results indicated that Bmi-1 and PADI4 positively regulate carcinogenesis and progression of ESCC.

The role of peptidylarginine deiminase 4 in ovarian cancer cell tumorigenesis and invasion.

Peptidylarginine deiminase 4 (PADI4) is an enzyme that converts both histone arginine and mono-methyl arginine residues to citrulline, and it has been detected in various subtypes of ovarian cancer. However, the mechanism of action of PADI4 in ovarian carcinogenesis remains unknown. To examine the function of PADI4, we transfected two ovarian cancer cell lines, wild-type p53 A2780 and p53-null SKOV3, with PADI4-siRNA and negative control siRNA. The proliferation of both A2780 and SKOV3 cells decreased significantly following PADI4-siRNA treatment (P A2780 < 0.01; P SKOV3 < 0.001). The invasion and migration ability of A2780 cells also significantly decreased in response to PADI4-siRNA treatment (P < 0.001), but SKOV3 cells showed no such decrease. The apoptotic rate of A2780 cells increased in the presence of PADI4-siRNA, but there was no such increase in SKOV3 cells (P > 0.05). PCR arrays of A2780 cells treated with PADI4-siRNA revealed the up-regulated expression of six genes, including cell death-inducing DFFA-like effector a (CIDEA) and tumor necrosis factor receptor superfamily member 9 (TNFRSF9), and the down-regulation of seven genes, including integrin beta 3 (ITGB3) and BCL2-antagonist/killer 1 (BAK1). These results suggest an important role for PADI4 in the p53 pathway and the regulation of the proliferation, apoptosis, invasion and migration of ovarian cancer cells. Our study also demonstrated that PADI4 contributes to tumor metastasis by regulating the gene expression of insulin-like growth factor 1 (IGF1) and WAS/WASL-interacting protein family member 1 (WIPF1).

Ovarian carbonyl reductase-like 20beta-hydroxysteroid dehydrogenase shows distinct surge in messenger RNA expression during natural and gonadotropin-induced meiotic maturation in nile tilapia.

Meiotic maturation in fish is accomplished by maturation-inducing hormones. 17alpha,20beta-Dihydroxy-4-pregnen-3-one (17alpha,20beta-DP) was identified as the maturation-inducing hormone of several teleosts, including Nile tilapia. A cDNA encoding 20beta-hydroxysteroid dehydrogenase (20beta-HSD), the enzyme that converts 17alpha-hydroxyprogesterone to 17alpha,20beta-DP, was cloned from the ovarian follicle of Nile tilapia. Genomic Southern analysis indicated that 20beta-HSD probably exists as a single copy in the genome. The Escherichia coli-expressed cDNA product oxidized both carbonyl and steroid compounds, including progestogens, in the presence of NADPH. Carbonyl reductase-like 20beta-HSD is broadly expressed in various tissues of tilapia, including ovary, testis, and gill. Northern blot and reverse transcription polymerase chain reaction analyses during the 14-day spawning cycle revealed that the expression of 20beta-HSD in ovarian follicles is low from Day 0 to Day 8 after spawning and is not detectable on Day 11. Distinct expression was evident at Day 14, the day of spawning. In males, 20beta-HSD expression was observed continually in mature testes but not in immature testes of 30-day-old fish. In vitro incubation of postvitellogenic immature follicles (corresponding to Day 11 after spawning) with hCG induced the expression of 20beta-HSD mRNA transcripts within 1-2 h, followed by the final meiotic maturation of oocytes. In tissues such as gill, muscle, brain, and pituitary, however, hCG treatment did not induce any changes in the levels of mRNA transcripts. Actinomycin D blockade of hCG-induced 20beta-HSD expression and final oocyte maturation demonstrated the involvement of transcriptional factors. The carbonyl reductase-like 20beta-HSD plays an important role in the meiotic maturation of tilapia gametes.