Effects of resistin-like molecule β over-expression on gastric cancer cells in vitro

Investigating resistin like beta (RETNLB) as a tumor promoter for oral squamous cell carcinoma

BACKGROUND

Oral cavity cancer ranks the sixth most common malignancy worldwide, of which oral squamous cell carcinoma is the predominant type. This study aimed to investigate the function and the underlying mechanism of resistin like beta (RETNLB) in oral squamous cell carcinoma.

METHODS

The data of oral squamous cell carcinoma samples from The Cancer Genome Atlas database was used to examine RETNLB expression and assess its correlation with the clinical outcomes. Biological functions of RETNLB on the growth, invasion and migration of cells were determined by cell counting kit 8, clonogenic growth, and Transwell assays. Gene set enrichment analysis was utilized to identify the important gene sets associated with RETNLB expression, which was further confirmed by western blot.

RESULTS

We found that RETNLB was upregulated in oral squamous cell carcinoma tissues and cells. High expression of RETNLB was closely linked to age and pathological tumor, and significantly related to poor survival of oral squamous cell carcinoma patients. Further functional experiments showed that knockdown of RETNLB significantly reduced the viability, mobility and invasiveness of cells. Moreover, gene set enrichment analysis suggested that Toll-like receptor signaling pathway was significantly correlated with high RETNLB expression. Further western blot analysis verified that silencing RETNLB could notably suppress the protein levels of Toll-like receptor 2, Toll-like receptor 4 and phosphor- extracellular signal-regulated kinase.

CONCLUSIONS

These results suggested that downregulation of RETNLB may restrain the progression of oral squamous cell carcinoma by inactivating TLR/2/4/ERK pathway.

Helicobacter pylori Infection Facilitates the Expression of Resistin-like Molecule Beta in Gastric Carcinoma and Precursor Lesions

Helicobacter pylori (H. pylori) was reported to be associated with gastric carcinogenesis. Resistin-like molecule beta (RELMβ), a recently described goblet cell-specific protein, was demonstrated to aberrantly express in gastric cancer and correlated with its clinicopathological features. This study aimed to examine the association between H. pylori and RELMβ expression in gastric carcinoma and precursor lesions. H. pylori infection and RELMβ expression were immunohistochemically evaluated in gastric biopsies from 230 patients. The biopsies consisted of normal gastric mucosa (n=20), mucosa with chronic gastritis (n=41), intestinal metaplasia (n=42), dysplasia (n=31), intestinal-type adenocarcinoma (n=56), and diffuse-type adenocarcinoma (n=40). RELMβ expression was measured in gastric biopsies after H. pylori eradication therapy in a subgroup of 32 patients. Cultured gastric cancer cell line SGC-7901 was infected with H. pylori strains, and RELMβ expression was detected by reverse transcription PCR, real-time PCR and Western blotting. Higher RELMβ immunoreactivity was observed in H. pylori-positive intestinal metaplasia (P=0.003), dysplasia (P=0.032), intestinal-type (P=0.037) and diffuse-type adenocarcinomas (P=0.001) than in H. pylori-negative specimens. Expression rates of RELMβ in dysplasia (P=0.005), intestinal-type adenocarcinoma (P<0.001), and diffuse-type adenocarcinoma (P=0.001) were significantly correlated with the grade of H. pylori density. In addition, H. pylori eradication reduced the RELMβ intensity in intestinal metaplasia (P=0.001). Infection of gastric cancer SGC-7901 cells with cag pathogenicity island (PAI)-positive H. pylori TN2, but not with its PAI totally deleted mutant (TN2-ΔPAI) for 4-8 h, resulted in enhanced protein and transcript levels of RELMβ (P<0.05). In summary, our study suggested that H. pylori infection facilitated the expression of RELMβ in gastric garcinoma and precursor lesions.

microRNA-558 facilitates the expression of hypoxia-inducible factor 2 alpha through binding to 5'-untranslated region in neuroblastoma

Neuroblastoma (NB) is the most common extracranial solid tumor in childhood. Our previous studies have shown that hypoxia-inducible factor 2 alpha (HIF-2α), one member of the bHLH-PAS transcription factor family, facilitates the progression of NB under non-hypoxic conditions. However, the mechanisms underlying HIF-2α expression in NB still remain largely unknown. Herein, through analyzing the computational algorithm programs, we identified microRNA-558 (miR-558) as a crucial regulator of HIF-2α expression in NB. We demonstrated that miR-558 promoted the expression of HIF-2α at translational levels in NB cells through recruiting Argonaute 2 (AGO2). Mechanistically, miR-558 directly bound with its complementary site within 5′-untranslated region (5′-UTR) to facilitate the binding of AGO2 to eukaryotic translation initiation factor 4E (eIF4E) binding protein 1, resulting in increased eIF4E enrichment and HIF-2α translation. In addition, miR-558 promoted the growth, invasion, metastasis, and angiogenesis of NB cells in vitro and in vivo, and these biological features were rescued by knockdown of AGO2, eIF4E, or HIF-2α. In clinical NB specimens, miR-558, AGO2, and eIF4E were highly expressed and positively correlated with HIF-2α expression. Patients with high miR-558, HIF-2α, AGO2, or eIF4E levels had lower survival probability. Taken together, these results demonstrate that miR-558 facilitates the expression of HIF-2α through bindingto its 5′-UTR, thus promoting the tumorigenesis and aggressiveness of NB.

Deletion of resistin-like molecule-beta attenuates angiotensin II-induced abdominal aortic aneurysm

In the present study, we want to test whether deletion of resistin-like molecule-beta (RELMβ) attenuates angiotensin II (Ang II)-induced formation of abdominal aortic aneurysm (AAA). RELMβ gene expression was inhibited by siRNA both in vivo and in vitro. Apolipoprotein E-knockout (ApoE^−/−) mice were randomly divided into saline, Ang II, siRNA negative control (si-NC) and siRNA RELMβ (si-RELMβ) groups (n=15 each), and mice in the last three groups underwent Ang II infusion for 4 weeks to induce AAA. RELMβ gene deficiency significantly decreased AAA incidence and severity, which was associated with reduced macrophage accumulation and decreased expression of proinflammatory cytokines (monocyte chemoattractant protein 1 and interleukin 6), matrix metalloproteinase 2 (MMP-2) and MMP-9 in the aortic wall. In cultured macrophages, RELMβ deficiency blunted the response of macrophages to Ang II and downregulated the levels of proinflammatory cytokines, MMP-2 and MMP-9. Recombinant RELMβ promoted the secretion of proinflammatory cytokines, MMP-2 and MMP-9 in macrophages and activated extracellular signal-regulated kinase 1/2 (ERK1/2) and c-Jun N-terminal kinase (JNK) signaling, which was reversed with pretreatment with inhibitors of ERK1/2 and JNK. Deletion of RELMβ attenuated Ang II-induced AAA formation in ApoE^−/− mice. The inherent mechanism may involve the reduced expression of proinflammatory cytokines, MMP-2 and MMP-9, which was mediated by ERK1/2 and JNK activation. Therefore, inhibiting RELMβ secretion may be a novel approach for anti-aneurysm treatment.

IFN-γ regulates human dental pulp stem cells behavior via NF-κB and MAPK signaling

During caries, dental pulp expresses a range of pro-inflammatory cytokines in response to the infectious challenge. Interferon gamma (IFN-γ) is a dimerized soluble cytokine, which is critical for immune responses. Previous study has demonstrated that IFN-γ at relative high concentration (100 ng/mL) treatment improved the impaired dentinogenic and immunosuppressive regulatory functions of disease-derived dental pulp stem cells (DPSCs). However, little is known about the regulatory effects of IFN-γ at relative low concentration on healthy DPSC behavior (including proliferation, migration, and multiple-potential differentiation). Here we demonstrate that IFN-γ at relatively low concentrations (0.5 ng/mL) promoted the proliferation and migration of DPSCs, but abrogated odonto/osteogenic differentiation. Additionally, we identified that NF-κB and MAPK signaling pathways are both involved in the process of IFN-γ-regulated odonto/osteogenic differentiation of DPSCs. DPSCs treated with IFN-γ and supplemented with pyrrolidine dithiocarbamate (PDTC, an NF-κB inhibitor) or SB203580 (a MAPK inhibitor) showed significantly improved potential for odonto/osteogenic differentiation of DPSCs both in vivo and in vitro. These data provide important insight into the regulatory effects of IFN-γ on the biological behavior of DPSCs and indicate a promising therapeutic strategy for dentin/pulp tissue engineering in future endodontic treatment.

Resistin-Like Molecule-β Promotes Invasion and Migration of Gastric Carcinoma Cells

Background

Resistin-like molecule-β (RELMβ) is a novel secretory protein from intestinal goblet cells and participates in epithelial differentiation, tumor occurrence, and immune response. RELMβ is absent in normal gastric mucosa but is abundantly expressed in gastric carcinoma tissues, and is correlated with tumor invasion and metastasis. Epithelial-mesenchymal transition (EMT) is an important mechanism governing tumor cell invasion. This study thus investigated the modulation of RELMβ in gastric cancer metastasis and its correlation with EMT.

Material/Methods

We used RELMβ-low expression AGS cell line of gastric cancer and normal mucosa cell line GES1 as in vitro models, on which RELMβ0-expressing vector was transfected. The invasion and migration of cells were quantified by Transwell assay. EMT-related protein including E-cadherin, N-cadherin, Snail, and Vimentin were detected by Western blotting in transfected AGS cells.

Results

RELMβ transfection significantly potentiated invasion and migration abilities of AGS cells, whose RELMβ protein level was significantly elevated compared to those in untransfected AGS or GES1 cells. After RELMβ transfection, EMT-related proteins, including N-cadherin, Snail, and Vimentin levels, were elevated, but E-cadherin expression was depressed.

Conclusions

RELMβ-overexpression can facilitate invasion and migration of gastric carcinoma cells and it increases the expression of EMT-related proteins, such as N-cadherin, Snail, Vimentin, but decreases E-cadherin level, thus promoting the progression of EMT.

Resistin as a biomarker linking obesity and inflammation to cancer: potential clinical perspectives

Excess body weight is associated with various types of malignancies. Resistin, originally described as an adipocyte-specific hormone modulating insulin resistance in rodents, may exhibit proliferative, antiapoptotic, proinflammatory, proangiogenic and metastatic properties. Accumulating evidence supports a role of resistin as a risk factor and potential diagnostic and prognostic biomarker in cancer. In this report, the current knowledge about resistin's properties and pathophysiological implications in cancer in the context of dysregulated adipose tissue in obesity is summarized; clinical translations, preventive and therapeutic considerations, and future perspectives in the field of resistin research are discussed. At the same time, several enigmatic issues involving resistin receptor and signaling pathways remain to be clarified in order to unmask its ontological role in cancer pathophysiology.

JWA suppresses tumor angiogenesis via Sp1-activated matrix metalloproteinase-2 and its prognostic significance in human gastric cancer

JWA, a multifunctional microtubule-binding protein, plays an important role in regulating tumor metastasis via inhibition of matrix metalloproteinase-2 (MMP-2). Recent investigations suggest that MMP-2 is an angiogenesis-associated molecule. In this study, we provide novel evidence that JWA inhibits tumor angiogenesis in gastric cancer (GC). In two independent retrospective GC cohorts, we found that the expression of JWA was downregulated and that of MMP-2 was upregulated in GC tissues compared with the same in normal gastric mucosa. For patients treated with surgery alone, a strong and independent negative prognostic value was shown for low JWA and high MMP-2 expressions separately, which was even stronger when combined (hazard ratio = 7.75, P < 0.001, in the training cohort; hazard ratio = 2.31, P < 0.001, in the validation cohort). Moreover, we found that loss of JWA expression was strongly correlated with increased GC angiogenesis. In vitro, JWA inhibited MMP-2 at both messenger RNA and protein levels by modulating Sp1 activity. Knockdown of endogenous JWA resulted in enhanced human umbilical vein endothelial cell tube formation and MMP-2 expression. Furthermore, JWA was found to inhibit Sp1 activity via an ubiquitin-proteasome-dependent mechanism and to downregulate the expression of the proangiogenic MMP-2. Our findings imply that JWA and MMP-2 may serve as promising prognostic markers in resectable GC, with JWA as a useful biomarker of angiogenesis in GC and a potential therapeutic target by MMP-2 modulation.

Resistin promotes the expression of vascular endothelial growth factor in ovary carcinoma cells

Resistin is a novel hormone that is secreted by human adipocytes and mononuclear cells and is associated with obesity, insulin resistance and inflammation. Recently, resistin has been postulated to play a role in angiogenesis. Here, we investigated the hypothesis that resistin regulates ovary carcinoma production of vascular endothelial growth factor (VEGF) and the angiogenic processes. We found that in human ovarian epithelial carcinoma cells (HO-8910), resistin (10–150 ng/mL) enhanced both VEGF protein and mRNA expression in a time- and concentration-dependent manner, as well as promoter activity. Furthermore, resistin enhanced DNA-binding activity of Sp1 with VEGF promoter in a PI3K/Akt-dependent manner. PI3K/Akt activated by resistin led to increasing interaction with Sp1, triggering a progressive phosphorylation of Sp1 on Thr453 and Thr739, resulting in the upregulation of VEGF expression. In an in vitro angiogenesis system for endothelial cells (EA.hy926) co-cultured with HO-8910 cells, we observed that the addition of resistin stimulated endothelial cell tube formation, which could be abolished by VEGF neutralizing antibody. Our findings suggest that the PI3K/Akt-Sp1 pathway is involved in resistin-induced VEGF expression in HO-8910 cells and indicates that antiangiogenesis therapy may be beneficial treatment against ovarian epithelial carcinoma, especially in obese patients.