[Corrigendum] Synergic effect between 5­fluorouracil and celecoxib on hypoxic gastric cancer cells.

Following the publication of the above article, the authors have realized that Fig. 2 was published with an incorrect data panel: Essentially, Fig. 2D was erroneously selected from the representative images of the Fig. 1C data group during figure compilation. The authors were able to locate their original data, and the corrected version of Fig. 2, featuring the corrected data panel for Fig. 2D, is shown below. All the authors agree with this Corrigendum, and are grateful to the Editor of Molecular Medicine Reports for allowing them to publish it. The authors also regret that this inadvertent error was included in the paper, even though it did not substantially alter any of the major conclusions reported in the study, and apologize to the readership for any inconvenience caused. [the original article was published in Molecular Medicine Reports 11: 1160­1166, 2014; DOI: 10.3892/mmr.2014.2783].

Knockdown of ARK5 expression suppresses invasion of ovarian cancer cells.

The aim of the current study was to investigate the effects and the molecular mechanisms of ARK5 in ovarian cancer cell invasion. The plasmid pGCsilencerU6/GFP/Neo­RNAi­ARK5 and the control vector with a scramble sequence were transfected into SKOV3 cells to establish ARK5­deficient SKOV3 cells (siARK5/SKOV3) and a control cell line (Scr/SKOV3), respectively. Reverse transcription­polymerase chain reaction (RT­PCR) and Western blot analysis were used to determine the mRNA and protein expression levels of ARK5. Migration and invasion abilities of SKOV3 cells were determined in chemotaxis and invasion assays, respectively. The epidermal growth factor­1 (EGF­1)­induced expression of matrix metallopeptidase (MMP)­2 and MMP­9, epithelial­mesenchymal transition (EMT) and phosphorylation of mechanistic target of rapamycin kinase (mTOR) in siARK5/SKOV3 and Scr/SKOV3 cells were detected by western blot. RT­PCR and western blot analyses demonstrated that the expression of ARK5 was significantly downregulated in siARK5/SKOV3 cells at the mRNA and protein levels (P<0.01). The migration and invasion abilities of siARK5/SKOV3 cells were markedly decreased compared with Scr/SKOV3 cells (P<0.01). In addition, the results demonstrated that EGF­1­induced expression of MMP­2 and MMP­9, EMT and phosphorylation of mTOR were suppressed in siARK5/SKOV3 cells as compared with Scr/SKOV3 cells (P<0.01). The current study demonstrated that ARK5 is a critical factor involved in SKOV3 cell invasion and ARK5 increases invasive potential by promoting EMT and activating the Akt­mTOR­MMPs pathway.

Grb2-associated binder 2 expression and its roles in uveal melanoma invasion.

Uveal melanoma (UM) is characterized by high metastasis and poor prognosis. A more improved understanding of the metastatic mechanism in UM cells is essential for the design of molecular therapy. Grb2­associated binder 2 (Gab2) has been reported to serve important roles in the progression of various types of human cancer. However, the role of Gab2 in the migration and invasion of UM remains unclear. The present study sought to further assess the expression of Gab2 in UM and the role of Gab2 in the invasion of UM cells. Clinical UM tissue samples and UM cell lines were analyzed using western blot analysis for the expression of Gab2. RNA interference was used to investigate the effect of Gab2 on the migratory and invasive characteristics of UM cells in vitro. The expression levels of matrix metalloproteinase (MMP)2, MMP9 and fascin in Gab2­knockdown, and control cells were also detected using western blot analysis. A total of 20 clinical UM samples and a subset of UM cell lines were investigated with uniformly high Gab2 expression. In the in vitro experiment, reduction of Gab2 using small interfering RNA inhibited the migration and invasion of UM cells by mediating MMPs, and fascin expression. These data suggest that Gab2 is a useful prognostic marker for UM and a novel therapeutic target for UM metastasis intervention.

CC chemokine ligand 18(CCL18) promotes migration and invasion of lung cancer cells by binding to Nir1 through Nir1-ELMO1/DOC180 signaling pathway.

Non-small cell lung cancer (NSCLC) comprises nearly 80% of lung cancers and the poor prognosis is due to its high invasiveness and metastasis. CC chemokine ligand 18 (CCL18) is predominantly secreted by M2-tumor associated macrophages (TAMs) and promotes malignant behaviors of various human cancer types. In this study, we report that the high expression of CCL18 in TAMs of NSCLC tissues and increased expression of CCL18 in TAMs is correlated with the lymph node metastasis, distant metastasis, and poor prognosis NSCLC patients. CCL18 can increase the invasive ability of NSCLC cells by binding to its receptor Nir1. In addition, CCL18 is capable of modulating cell migration and invasion by regulating the activation of RAC1 which resulted in cytoskeleton reorganization in an ELMO1 dependent manner. Furthermore, we found that CCL18 could enhance adhesion of NSCLC cells via activating ELMO1-integrin ß1 signaling. Thus, CCL18 and its downstream molecules may be used as targets to develop novel NSCLC therapy. © 2016 Wiley Periodicals, Inc.

Autocrine IL-8 promotes F-actin polymerization and mediate mesenchymal transition via ELMO1-NF-κB-Snail signaling in glioma.

Glioma is the most common form of primary malignant brain cancers. Tumor cell invasiveness is a critical challenge in the clinical management of glioma patients. The invasive biological feature of glioma cell is stimulated by both autocrine and paracrine factors including chemokine IL-8. In this study, we report that the production of IL-8 is higher in glioma tissues and cells than adjacent nontumor tissues (ANT) and normal glial cells. Autocrine IL-8 can increase the invasive ability of glioma cells by binding to CXCR1. In addition, high expression of IL-8 indicates poor prognosis of glioma patients. Furthermore, IL-8 is capable of modulating cell migration and invasion by regulating the activation of RAC1 which resulted in cytoskeletal reorganisation in an ELMO1 dependent manner. Finally, we found that IL-8 could enhance mesenchymal transition(MT) of glioma cells by activating ELMO1-NF-κB-Snail signaling. Our data indicate that IL-8 autocrine is responsible for the invasive phenotype of glioma and IL-8 may be a useful prognostic marker for glioma and novel therapeutic target for glioma invasion intervention.

Synergic effect between 5­fluorouracil and celecoxib on hypoxic gastric cancer cells.

5­fluorouracil (5­FU) is commonly used in the treatment of gastric cancer; however, resistance to this drug occurs under hypoxic conditions. Celecoxib may be used to reverse this resistance. The aim of the present study was to elucidate the inhibitory effects and mechanisms of 5­FU and celecoxib on the gastric cancer cell line SGC7901 under hypoxic conditions. SGC7901 cells were divided into four groups: Hypoxic control group, 5­FU group, celecoxib group and 5­FU/celecoxib combination group. Following treatment, the inhibition rates of cells were determined using an MTT assay. Protein and messenger RNA (mRNA) expression of hypoxia­inducible factor 2α (HIF­2α), adenosine triphosphate­binding cassette sub­family G member 2 (ABCG2) and octamer binding protein 4 (Oct­4) were determined using immunohistochemistry, reverse transcription quantitative polymerase chain reaction (RT­qPCR) and western blot analysis. The results demonstrated that the 5­FU/celecoxib combination group had a significantly higher inhibition rate than the individually treated 5­FU and celecoxib groups (P<0.05); inhibition rates were 66.09, 52.61 and 46.1%, respectively. mRNA and protein expression levels of HIF­2α, ABCG2 and Oct­4 were significantly lower in the celecoxib and 5­FU/celecoxib combination groups (P<0.01) compared with those of the hypoxia control and 5­FU groups. The 5­FU group demonstrated the highest levels of the respective mRNA and proteins. In conclusion, the results of the present study indicated that celecoxib had anti­tumor effects, as it was shown to inhibit tumor cell growth via the inhibition of HIF­2α, ABCG2 and Oct­4. The 5­FU/celecoxib combination had a synergic effect on tumor growth inhibition. This therefore suggested that inhibition of HIF­2α, ABCG2 and Oct­4 may be a potential method of reducing chemotherapy resistance and enhancing the effectiveness of chemotherapy treatment.

Astragalus Polysaccharide Protects Astrocytes from Being Infected by HSV-1 through TLR3/NF-κB Signaling Pathway.

Astragalus polysaccharide (APS) is the most immunoreactive substance in Astragalus. APS can regulate the body's immunity and is widely used in many immune related diseases. However, till now, there is little information about its contribution to the protection of astrocytes infected by virus. Toll-like receptor 3 (TLR3) is a key component of the innate immune system and has the ability to detect virus infection and trigger host defence responses. This study was undertaken to elucidate the protective effect of APS on herpes simplex virus (HSV-1) infected astrocytes and the underlying mechanisms. The results showed that APS protected the astrocytes from HSV-1 induced proliferation inhibition along with increasing expression of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) markedly. Moreover, APS significantly promoted the expression of Toll-like receptor 3 (TLR3) and the activation of nuclear factor-κB (NF-κB) in astrocytes. In addition, while astrocytes were pretreated with TLR3 antibody before adding HSV-1 and APS, the expression of TLR3, TNF-α, and IL-6 and the activation of NF-κB decreased sharply. These results indicate that APS can protect astrocytes by promoting immunological function provoked by HSV-1 through TLR3/NF-κB pathway.

HSV-1 activates NF-kappaB in mouse astrocytes and increases TNF-alpha and IL-6 expression via Toll-like receptor 3.

OBJECTIVE: To investigate the effect of HSV-1 infection via TLR3 on the transcriptional activity of NF-kappaB and the expression of cytokines TNF-alpha and IL-6 in astrocytes. METHODS: HSV-1-infected primary astrocytes were cultured until the third passage and the mRNA and protein levels of TLR3, NF-kappaB, TNF-alpha, and IL-6 were assessed by immunofluorescence, RT-PCR, and Western blot. The effects of the NF-kappaB inhibitor pyrrolidine dithiocarbamate (PDTC) and TLR3-neutralizing antibody on the expression of NF-kappaB, TNF-alpha, and IL-6 were investigated. RESULTS: Uninfected astrocytes expressed TLR3 and NF-kappaB at the mRNA and protein levels. After infection with HSV-1, the TLR3 mRNA and protein levels were up-regulated and NF-kappaB protein was highly expressed. Also, the mRNA and protein levels of TNF-alpha and IL-6 were up-regulated. Pyrrolidine dithiocarbamate inhibited NF-kappaB activation, resulting in the down-regulation of nuclear NF-kappaB protein, which led to the down-regulation of the mRNA and protein levels of TNF-alpha and IL-6. After blocking astrocyte membrane TLR3, the nuclear NF-kappaB protein expression was down-regulated and the mRNA and protein levels of TNF-alpha and IL-6 were increased. The antiviral functions of astrocytes were weaker, as reflected by higher HSV-1 glycoprotein D (gD) mRNA expression and increased HSV-1 titers. CONCLUSION: Astrocytes infected with HSV-1 can activate NF-kappaB via TLR3 so as to up-regulate the expression of TNF-alpha and IL-6 that have antiviral functions.

Gab2 expression in glioma and its implications for tumor invasion.

Gliomas are characterized by high invasiveness and poor prognosis. Better understanding of the mechanism of invasion in glioma cells is essential to the design of effective therapy. Recently Grb2-associated binder 2 (Gab2), a member of the DOS/Gab family of scaffolding adapters, has been reported to play important roles in the development and progression of human cancers. However, it is not known whether Gab2 has any role in the migration and invasion of gliomas. This study attempts to investigate the association between Gab2 expression and progression of gliomas and the molecular mechanism of Gab2 in the glioma cell invasion. Methods. The expression of Gab2 in pairs of matched glioma tissues and their normal brain tissues was detected by Western blot. Immunohistochemistry was applied to evaluate the expression of Gab2 in 163 cases of histologically diagnosed gliomas. The invasive character of Gab2 decreased glioma cells and control glioma cells were investigated in vitro and in vivo in SCID mice brain. Results. Gab2 is found to be high expressed in gliomas and a subset of cancer cell lines. Statistical analysis suggested that the up-regulation of Gab2 correlated with the WHO grade of gliomas (p < 0.01) and that patients with high Gab2 expression levels exhibited shorter survival time (p < 0.01). In an animal experiment, knockdown of Gab2 through siRNA inhibited invasive ability of glioma cells into the brain of SCID mice. In cell research, reduction of Gab2 by siRNA inhibits the migration and invasion of glioma cells by mediating cytoskeleton rearrangement and MMPs expression. Additionally, IGF-1-induced pAkt and pmTOR phosphorylation was suppressed by the knockdown of Gab2. Conclusion. Gab2 may be a useful prognostic marker for gliomas and a novel therapeutic target for glioma invasion intervention.