Role of Peroxiredoxin 1 Induced by Epstein-Barr Virus Infection in Nasopharyngeal Carcinoma

BACKGROUND/AIM

Nasopharyngeal carcinoma (NPC), a common cancer in Southern China, is associated with Epstein-Barr Virus (EBV) infection. Although many therapies for NPC have been established, the definite role of EBV in NPC remains unclear. Therefore, this work focuses on LMP2A, a latent EBV gene, and investigates whether LMP2A is related to peroxiredoxin 1 (PRDX1) in EBV-positive NPC.

MATERIALS AND METHODS

The mRNA and protein expression levels of LMP2A, PRDX1, and beta-catenin were compared in patient samples. To identify molecular mechanisms, EBV-negative NP69 and EBV-positive C666-1 NPC cell lines were used. After making an agar cell block for cell slides, the intensity of LMP2A expression was observed visually. To measure the level of reactive oxygen species, both fluorescence microscope and flow cytometry were used. To investigate the intracellular signaling molecular mechanisms with and without the LMP2A gene, reverse transcription polymerase chain reaction and western blotting were used.

RESULTS

Both patient samples and cells of nasopharyngeal carcinoma infected with EBV had increased expression of LMP2A compared with controls, and high ROS levels were identified. Cell viability assay showed that LMP2A promoted cell growth by regulating gene expression. Furthermore, LMP2A induced the expression of PRDX1 and beta-catenin. LMP2A also increased the expression of both cyclin B1 and cyclin D1.

CONCLUSION

In NPC cells, PRDX1 and beta-catenin were regulated through LMP2A expression, which reduced cell growth through cell cycle-related gene expression. This study suggests that LMP2A could be a target molecule for inhibiting cancer progression in NPC cells infected with EBV.

Targeting isoforms of RON kinase (MST1R) drives antitumor efficacy

Recepteur d'origine nantais (RON, MST1R) is a single-span transmembrane receptor tyrosine kinase (RTK) aberrantly expressed in numerous cancers, including various solid tumors. How naturally occurring splicing isoforms of RON, especially those which are constitutively activated, affect tumorigenesis and therapeutic response, is largely unknown. Here, we identified that presence of activated RON could be a possible factor for the development of resistance against anti-EGFR (cetuximab) therapy in colorectal cancer patient tissues. Also, we elucidated the roles of three splicing variants of RON, RON Δ155, Δ160, and Δ165 as tumor drivers in cancer cell lines. Subsequently, we designed an inhibitor of RON, WM-S1-030, to suppress phosphorylation thereby inhibiting the activation of the three RON variants as well as the wild type. Specifically, WM-S1-030 treatment led to potent regression of tumor growth in solid tumors expressing the RON variants Δ155, Δ160, and Δ165. Two mechanisms for the RON oncogenic activity depending on KRAS genotype was evaluated in our study which include activation of EGFR and Src, in a trimeric complex, and stabilization of the beta-catenin. In terms of the immunotherapy, WM-S1-030 elicited notable antitumor immunity in anti-PD-1 resistant cell derived mouse model, likely via repression of M1/M2 polarization of macrophages. These findings suggest that WM-S1-030 could be developed as a new treatment option for cancer patients expressing these three RON variants.

Bone destruction in chronic otitis media is not mediated by the RANKL pathway or estrogen receptor-alpha

BACKGROUND

Chronic otitis media with or without cholesteatoma progresses with various degrees of bone resorption and remodeling. Estrogen mediates osteoprotective effects through the receptor activator of NF-κB ligand (RANKL) pathway, which is mainly mediated by estrogen receptor-alpha (ER-α).

OBJECTIVES

The present study investigated the expression patterns of receptor activator of NF-κB (RANK), osteoprotegerin (OPG), RANKL, and ER-α in pathological tissue from patients with chronic otitis media to determine the roles of those factors in osteolytic mechanisms underlying the pathogenesis of chronic otitis media.

METHODS

Normal and pathological specimens from 18 patients with chronic otitis media were examined.

RESULTS

There were no significant differences in RANK, OPG, RANKL, or ER-α mRNA expression between normal and pathological specimens of epithelial tissue.

CONCLUSIONS

Our findings suggested that RANK, OPG, RANKL, and ER-α are not associated with the bone destruction in chronic otitis media; other cytokines may directly activate the osteoclasts in chronic otitis media.

APX‑115A, a pan‑NADPH oxidase inhibitor, reduces the degree and incidence rate of dry eye in the STZ‑induced diabetic rat model

Dye eye disease (DED) is a common ocular disorder in patients with diabetes. It has been reported that APX-115A, a pan-nicotinamide adenine dinucleotide phosphate (NAPDH) oxidase inhibitor, has an apoptosis-inducing effect on Epstein-Barr virus-infected retinal epithelial cells, but its effects in DED are poorly understood. Therefore, a rat model of diabetes was used in the present study to investigate whether APX-115A has an impact on DED in diabetic rats. A diabetic model was established in male Sprague Dawley rats via the intraperitoneal injection of streptozotocin. The eyeballs of the rats were treated with a solution containing APX-115A or a saline control. Tear secretion was measured with the phenol red thread tear test, and the morphology of the eyeball and lacrimal gland tissues was determined using hematoxylin and eosin staining. In addition, localization of NAPDH oxidase 2 (NOX2) in the eyeball and lacrimal gland tissues was detected by immunohistochemistry. The APX-115A treatment had no effect on body weight, blood glucose level or the size of the lacrimal glands. However, morphological changes, namely intracellular vacuoles and acinar atrophy, were observed in the lacrimal glands of the diabetic rats, and APX-115A treatment attenuated these changes. Immunohistochemistry revealed that NOX2 expression was decreased in the lacrimal glands of the diabetic rats, and APX-115A treatment did not attenuate the reduction in NOX2. The corneas of the diabetic rats treated with APX-115A exhibited no change in thickness but had lower NOX2 expression levels compared with those of the control diabetic rats. APX-115A also increased tear secretion and ameliorated the histological changes associated with diabetes. Furthermore, the NOX2 expression levels in the corneas of the diabetic rats treated with APX-115A were restored to the levels observed in normal rats. These findings suggest that APX-115A has potential as a therapeutic agent for DED.

Upregulation of VSIG4 in Type 2 Diabetic Kidney Disease

Fibrosis is the final common finding in patients with advanced diabetic kidney disease. V-set Ig domain containing 4 (VSIG4) is related to fibrosis in several diseases. It also contributes to fibrosis under high-glucose conditions in renal tubule cells. To determine the role of VSIG4 in type 2 diabetes, we examined VSIG4 expression in a type 2 diabetic animal model and podocyte. Urinary excretion of albumin and VSIG4 was significantly higher in db/db mice than in the control group. Urine VSIGs levels for 6 h were about three-fold higher in db/db mice than in db/m mice at 20 weeks of age: 55.2 ± 37.8 vs. 153.1 ± 74.3 ng, p = 0.04. Furthermore, urinary VSIG4 levels were significantly correlated with urinary albumin levels (r = 0.77, p < 0.01). Intrarenal VSIG4 mRNA expression was significantly higher in db/db mice than in control mice (1.00 ± 0.35 vs. 1.69 ± 0.77, p = 0.04). Further, VSIG4 expression was almost twice as high in db/db mice at 20 weeks of age. Intrarenal VSIG immunoreactivity in db/db mice was also significantly higher than that in control mice. In cultured podocytes, both high glucose and angiotensin II significantly upregulated the expression of VSIG4 mRNA and protein. In conclusion, VSIG4 was upregulated in an animal model of type 2 diabetes and was related to albuminuria and pro-fibrotic markers. Considering these relationships, VSIG4 may be an important mediator of diabetic nephropathy progression.

One Autopsy Proved Neocortical Lewy Body Disease Without the Involvement of the Olfactory Bulb and Brainstem

Lewy bodies (LBs) and Lewy neurites (LNs) are pathological hallmarks of Parkinson's disease (PD) or dementia with LBs (DLB). Incidental Lewy body disease (iLBD) is defined when LBs and LNs are found in the brain of normal elderly individuals. A 65-year-old man presented with autopsy-proven Lewy body pathology (LBP). He had never complained of cognitive impairments or parkinsonian motor symptoms, and he had always maintained independence in activities of daily living. Hypopigmentations in the locus coeruleus and substantia nigra were discovered during the autopsy. The patient showed severe-to-extremely severe LBs in the neocortex and limbic areas, except in the nucleus basalis of Meynert, amygdala, and brainstem, according to microscopic findings. Hence, using several of the previously known staging systems, it was difficult to classify the patient's LBP type. Furthermore, these findings were unique because they had never been observed before in iLBD.

A Case of Pathologically Confirmed Corticobasal Degeneration Initially Presenting as Progressive Supranuclear Palsy Syndrome

Progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD) overlap clinically with parkinsonism or extrapyramidal signs and pathologically with tauopathy. Asymmetric parkinsonism and cortical dysfunctions are classical features of CBD. However, symmetric parkinsonism, frequent falls, and supranuclear gaze palsy are key features of PSP. Despite biochemically classified as 4R tauopathies, tufted astrocytes of PSP and astrocytic plaque of CBD show pathologically important differences. Herein, we report a 68-year-old man with pathologically confirmed CBD. He was clinically suspected to have PSP because of progressive gait disturbances, frequent falls, and vertical saccade limitation. Neurological examination performed at age 71 revealed symmetrical bradykinesia, axial rigidity, and postural instability with worsening of early existing symptoms. Magnetic resonance imaging of the brain taken at age 70 detected midbrain and left frontotemporal atrophy and right middle cerebral artery infarction. Left frontotemporoparietal hypometabolism and asymmetrically decreased fluoro-propyl-carbomethoxy-iodophenyl-tropane uptake in the basal ganglia were observed. The autopsy was performed at the time of his death (at age 72), which revealed severe pallor of the substantia nigra and mildly hypopigmented locus ceruleus. AT8 immunohistochemistry and Gallyas staining revealed tau-positive neuronal and glial inclusions, astrocytic plaques, ballooned neurons, and numerous threads in both gray and white matter. No abnormal inclusions were revealed by beta-amyloid, α-synuclein and TDP-43 immunohistochemistry. In our case, cerebral infarction, periventricular and deep white matter ischemic changes, and midbrain atrophy were likely to produce PSP-CBD overlapping symptoms. However, our patient was finally confirmed to have CBD based on pathological findings such as astrocytic plaques.

Morphologic Changes in Esophageal Body Movement During Bolus Transport After Peroral Endoscopic Myotomy in Type III Achalasia

Background/Aims

The effect of peroral endoscopic myotomy (POEM) on esophageal body movement in achalasia is poorly understood. This study aims to evaluate morphological changes in esophageal body movement after POEM in type III achalasia by analyzing intraluminal ultrasound (US) images in comparison to type I and II achalasia.

Methods

Intraluminal US images and impedance values of the distal esophagus from 47 achalasia patients who underwent POEM or pneumatic dilatation (PD) (30 patients in the POEM group and 17 patients in the PD group) with pre- and post-procedural high-resolution impedance manometry and intraluminal US examinations were analyzed. The muscle thickness (MT), muscle cross-sectional area, lumen cross-sectional area (LCSA), contractility and distensibility indices, swallow-to-distension interval, and distension duration during each bolus transport were analyzed.

Results

The MT increased and LCSA decreased significantly (P < 0.001), but the contractility index was not improved after POEM or PD in type I achalasia. Baseline MT increased and LCSA decreased significantly after POEM and PD in type II achalasia (P < 0.001). In contrast, MT and the swallow-to-distension interval decreased and the distension LCSA/duration and contractility index increased after POEM in type III achalasia (P < 0.001). In contrast to type I and II achalasia, in type III achalasia, these effects were unique to the POEM group.

Conclusions

POEM decreased the esophageal LCSA by decreasing intrabolus pressure without improving contractility in type I and II achalasia. In contrast, POEM increased esophageal body distension and contractility and improved the inhibitory process during bolus transport in type III achalasia.

Olaparib-induced Apoptosis Through EBNA1-ATR-p38 MAPK Signaling Pathway in Epstein-Barr Virus-positive Gastric Cancer Cells

BACKGROUND

Epstein-Barr virus (EBV)-associated gastric cancer has been identified as a cancer subtype with definitive clinical and molecular characteristics. Although olaparib, a poly ADP ribose polymerase (PARP) inhibitor, is considered a potential effective agent for gastric cancer, the effect and underlying mechanism of olaparib on gastric cancer depending on EBV infection is not fully understood.

MATERIALS AND METHODS

EBV-positive SNU719 and EBV-negative SNU638 gastric cancer cell lines were used to identify the effects of olaparib using the trypan blue exclusion method and annexin V staining assay. To observe the underlying cellular signaling mechanisms of olaparib-induced cell death, Epstein-Barr virus nuclear antigen 1 (EBNA1) and signaling related molecule expression were assessed using transfection, silencing of specific genes using small interfering RNA (siRNA), western blotting and signaling inhibition assay.

RESULTS

Olaparib decreased the cell viability of EBV-positive SNU719 gastric cancer cells through caspase-3-dependent apoptosis in a dose dependent manner, whereas EBV-negative SNU638 gastric cancer cells showed drug resistance to olaparib. EBNA1 was expressed in SUN719 gastric cancer cells; however, ataxia telangiectasia and Rad3 related (ATR) and phosphorylated ATR kinase were expressed in SNU638 gastric cancer cells. EBNA1 transfection decreased ATR phosphorylation through p38 mitogen-activated protein kinase (MAPK) phosphorylation in SUN638 gastric cancer cells, and silencing of ATR kinase increased the susceptibility of these cells to olaparib treatment. Moreover, VE-821, an ATR kinase specific inhibitor, also increased the sensitivity of SNU638 cells to olaparib. In contrast, SB203580, a p38 MAPK inhibitor, inhibited this increase in sensitivity to olaparib by EBNA1 transfection.

CONCLUSION

Olaparib treatment led to different cellular responses depending on EBV infection in gastric cancer cell lines. These results provide new insights into the mechanism of olaparib-induced apoptosis in gastric cancer cells and suggest that EBV infection should be considered when developing new potential therapeutic agents for gastric cancer.

Effects of Epstein-Barr Virus Infection on the Response of Human Breast Cancer Cells to Nicotine

BACKGROUND/AIM

The purpose of our study was to test whether EBV infection affects the response of human breast cancer cells to nicotine. In addition, the underlying signaling mechanisms were evaluated.

MATERIALS AND METHODS

EBV-infected MDA-MB-231 and LMP1-transfected MDA-MB-231 breast cancer cells were established. Reverse transcription-polymerase chain reaction and western blotting were performed to evaluate nicotine receptor expression. To verify the functional role and underlying signaling mechanism of nicotine receptor expression induced by EBV infection, morphologic analysis, and proliferation and inhibition assays were performed.

RESULTS

Both EBV infection and LMP1 transfection increased cell proliferation and induced the up-regulation of α9-nAChR expression. Additionally, nicotine treatment induced tumorigenic activity in both EBV-infected and LMP1-transfected MDA-MB-231 breast cancer cells. Western blot and inhibitor assays showed that the nicotine-induced signaling was mediated through MAPK/ERK and AKT signaling pathways in EBV-infected and LMP1-transfected breast cancer cells, respectively.

CONCLUSION

These results suggest that EBV infection and EBV-related LMP1 may act as potential molecular targets for breast cancer risk associated with nicotine, and provide a novel insight into the mechanism of nicotine stimulation in EBV-positive breast cancer cells.

Erlotinib Activates Different Cell Death Pathways in EGFR-mutant Lung Cancer Cells Grown in 3D Versus 2D Culture Systems

BACKGROUND/AIM

Non-small cell lung cancer patients with epidermal growth factor receptor (EGFR) mutation have been shown to have a good response to erlotinib, a receptor tyrosine kinase inhibitor of EGFR. In this study, we found that the cell death pathways activated by erlotinib in 2D and 3D culture systems are different.

MATERIALS AND METHODS

The cell death pathways induced by erlotinib were evaluated by flow cytometry and immunoblotting in both 2D and 3D culture systems of EGFR mutant lung cancer cells.

RESULTS

Treatment with erlotinib induced caspase 8 activation and up-regulation of TNF-related apoptosis-inducing ligand (TRAIL) expression only in 3D cultures. Knockdown of TRAIL attenuated both erlotinib-induced activation of caspase-8 and apoptosis in 3D cultures. Erlotinib also increased LC3, an autophagy marker, expression and c-Jun N terminal kinase (JNK) activation. Both 3-MA as an autophagy inhibitor and SP600125 as a JNK inhibitor, significantly inhibited erlotinib-induced cell death.

CONCLUSION

Erlotinib induces apoptotic cell death in 3D cultures through an autophagy-TRAIL-JNK pathway.

Nicotinamide adenine dinucleotide phosphate oxidase inhibitor induces apoptosis on Epstein-Barr virus positive B lymphoma cells

Over-expression of nicotinamide adenine dinucleotide phosphate oxidase (Nox) isoform enzymes was recently reported in various cancers including Burkitt’s lymphoma (BL). However, the functions of Nox isoform enzymes in BL remain poorly understood. In this study, Nox isoform expression and the effects of a Nox-specific inhibitor were evaluated in Epstein-Barr virus (EBV)-positive Raji BL cells in comparison with EBV-negative Ramos BL cells. To evaluate Nox enzyme expression in Raji and Ramos BL cells, polymerase chain reaction (PCR) and western blot analysis were performed. To verify the intracellular signaling mechanism of the Nox inhibitor-induced apoptosis of Raji cells, WST-1 assay, trypan blue exclusion method, flow cytometry, PCR, western blotting, and bromodeoxyuridine staining were conducted. Experiments using the pan-caspase inhibitor z-VAD, reactive oxygen species scavenger N-acetyl-L-cysteine (NAC), and Bim inhibitor 1 were performed. PCR and western blot results showed that Nox isoform enzymes were highly expressed in EBV-positive BL Raji cells compared with EBV-negative BL Ramos cells. The Nox2 inhibitor induced apoptosis of Raji cells in time- and dose-dependent manners. The Nox2 inhibitor also caused up-regulation of Bim and Noxa, down-regulation of Mcl-1, translocation of Bax, release of cytochrome c, and caspase cascade activation, resulting in apoptosis. Furthermore, z-VAD, NAC, and BI-1 effectively blocked the Nox2 inhibitor-induced apoptosis of Raji cells. Taken together, these results provide a novel insight into the mechanism of Nox inhibitor-induced apoptosis and evidence for Nox as a therapeutic target to treat EBV-positive malignancies.

VSIG4 Induces Epithelial-Mesenchymal Transition of Renal Tubular Cells under High-Glucose Conditions

High glucose-mediated tubular injury contributes to the development and progression of diabetic nephropathy through renal tubulointerstitial fibrosis. V-set immunoglobulin-domain-containing 4 (VSIG4), a B7 family-related protein, is a complement receptor. Although the role of epithelial–mesenchymal transition (EMT) has been reported in several diseases, little is known about its relationship with VSIG4 under diabetic conditions. This study aimed to investigate the role of VSIG4 in human tubule cells stimulated by high glucose (HG, 55 mM). HG upregulated both mRNA and protein levels of VSIG4 in proximal tubule cells (HK-2 cells) and Madin Darby Canine Kidney cells. These upregulations were accompanied by increased expression of mesenchymal markers such as fibronectin, N-cadherin, matrix metalloproteinase 9, and vimentin, and by decreased expression of the epithelial marker, E-cadherin. The siRNA-mediated inhibition of VSIG4 in HK-2 cells restored the dysregulation of EMT in cells. Interestingly, VSIG4 inhibition did not affect the expression of transforming growth factor (TGF)-β, whereas inhibition of TGF-β reduced VSIG4 expression, subsequently suppressing fibrosis markers. These findings suggest that VSIG4 plays an important role in mediating renal tubular EMT through the downstream action of HG-induced TGF-β activation.

Celecoxib upregulates ULBP-1 expression in lung cancer cells via the JNK/PI3K signaling pathway and increases susceptibility to natural killer cell cytotoxicity

Lung cancer has the highest cancer mortality rate in the world, and effective therapies are still required. Cyclooxygenase-2 (COX-2) is highly expressed in numerous types of cancer, and is therefore considered a possible target of cancer treatment. Celecoxib, a selective COX-2 inhibitor, has binding pockets that interact with COX-2 and disrupt its enzymatic activities. In addition, celecoxib is able to affect cellular functions in a COX-2-independent manner. The present study aimed to investigate if celecoxib affected natural killer (NK) cell receptors and susceptibility to NK cell toxicity. For this purpose, PCR, immunoblotting, flow cytometry analysis and NK cell cytotoxicity assays were performed. The present study revealed that sublethal concentrations of celecoxib increased the expression levels of UL16-binding protein 1 (ULBP-1), a natural-killer group 2 member D (NKG2D) ligand, in lung cancer A549 and H460 cell lines. ULBP-1 mRNA and protein expression was induced in a dose- and time-dependent manner after celecoxib treatment. Expression levels of other NKG2D ligands, such as ULBP-2, ULBP-3, MHC class I-related chain A (MICA) and MICB did not change considerably compared to ULBP-1 in response to celecoxib treatment. Fluorescence microscopic images revealed abundant ULBP-1 in the cytoplasm after celecoxib treatment. Both JNK and PI3K may be involved in the induction of ULBP-1 expression after celecoxib treatment in A549 and H460 cells. In a NK cytotoxicity assay, celecoxib increased the sensitivity to NK cell-mediated cytotoxicity via interaction with ULBP-1 in lung cancer cells. Overall, the present results demonstrated that celecoxib treatment induced ULBP-1 expression in lung cancer cells, thereby increasing their susceptibility to NK cell cytotoxicity. These results suggest that the effects of conventional anticancer therapy may potentially be enhanced by using celecoxib, which targets COX-2, to enhance the sensitivity of lung cancer cells to NK cell-mediated cytotoxicity.

APX-115A, a pan-NADPH Oxidase Inhibitor, Induces Caspase-dependent Cell Death by Suppressing NOX4-ROS Signaling in EBV-infected Retinal Epithelial Cells

PURPOSE

Epstein-Barr virus is a γ-herpes virus that infects primary B cells and can transform infected cells into immortalized lymphoblastoid cell lines (LCL). The role of EBV in malignancies such as Burkitt's lymphoma and nasopharyngeal carcinoma is well understood, however, its role in EBV-infected retinal cells remains poorly understood. Therefore, we investigated the effect of EBV on the growth of retinal cells.

METHODS

Previously, we established and reported a cell line model to address the relationship between EBV infection and retinal cell proliferation that used adult retinal pigment epithelium (ARPE-19) and EBV infection. To determine the effect of EBV on ARPE-19 cells, cell death was measured by propidium iodine/annexin V staining and reactive oxygen species (ROS) were measured by FACS, and protein expression was evaluated using western blot analysis. Also, downregulation of LMP1 and NADPH oxidase 4 (NOX4) expression was accomplished using siRNA technology.

RESULTS

We found that ROS were dramatically increased in EBV-infected ARPE19 cells (APRE19/EBV) relative to the parental cell line. Additionally, the expression level of NOX4, a main source of ROS, was upregulated by EBV infection. Interestingly, downregulation of LMP1, one of the EBV viral onco-proteins, completely decreased EBV-induced ROS accumulation and the upregulation of NOX4. Treatment with APX-115A, a pan-NOX inhibitor, induced apoptotic cell death of only the EBV-infected ARPE19 cells but not the parental cell line. Pretreatment with z-VAD, a pan-caspase inhibitor, inhibited NOX inhibitor-induced cell death in ARPE19/EBV cells. Furthermore, APX-115A-induced cell death mediated the activation of JNK and ERK. Finally, we confirmed the expression level of NOX4, and APX-115A induced cell death of EBV-infected human primary retina epithelial cells and the activation of JNK and ERK.

CONCLUSION

Taken together, these our results suggest that APX-115A could be a therapeutic agent for treating EBV-infected retinal cells or diseases by inhibiting LMP1-NOX4-ROS signaling.

Ampelopsin Induces DR5-Mediated Apoptotic Cell Death in EBV-Infected Cells through the p38 Pathway

Ampelopsin (AMP) is a well-known flavonoid that exerts a number of biological and pharmacological effects including anticancer effects against several cancer cell lines. In this study, we investigated the anticancer activity of AMP against Epstein-Barr virus (EBV)-positive cells and its mechanism of action. Our results showed that AMP dose-dependently inhibited cell viability and induced apoptotic cell death in EBV-positive cells without cytotoxicity in EBV-negative cells. In particular, AMP induced caspase-8 dependent apoptosis via upregulation of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and death receptor (DR5). Knockdown of DR5 by RNA interference blocked AMP-induced apoptosis. Furthermore, AMP dose-dependently activated p38 mitogen-activated protein kinases (MAPKs) in EBV-positive cells. Additionally, SB203580 (a p38-MAPK inhibitor) effectively inhibited apoptotic cell death. These results demonstrate that treatment with AMP induces the apoptosis of EBV-positive cells through upregulation of TRAIL/DR5 and activation of p38 signaling. Therefore, these results provide experimental information for developing AMP as a new therapeutic drug against EBV-positive cancer.

LMP1 and 2A Induce the Expression of Nrf2 Through Akt Signaling Pathway in Epstein-Barr Virus-Transformed B Cells

The transcription factor Nrf2, which regulates the expression of antioxidant and cytoprotective enzymes, contributes to cell proliferation and resistance to chemotherapy. Nrf2 is also dysregulated in many cancers such as lung, head and neck, and breast cancers, but its role in Epstein-Barr virus (EBV)–transformed B cells is still not understood. Here, we investigated EBV infection-induced Nrf2 activation in B cells by analyzing translocation of Nrf2 from the cytosol to the nucleus. In addition, we confirmed expression of the target genes in response to increased Nrf2 activation in EBV-transformed B cells. We demonstrated that knockdown of LMP1 and 2A blocks the translocation of Nrf2 to the nucleus and reduces ROS production in EBV-transformed B cells. Further, we showed that inhibition of Akt prevents Nrf2 activation. Moreover, knockdown of Nrf2 induces apoptotic cell death in EBV-transformed B cells. In conclusion, our study demonstrates that Nrf2 promotes proliferation of EBV-transformed B cells through the EBV-related proteins LMP1 and 2A and Akt signaling, implicating Nrf2 as a potential molecular target for EBV-associated disease.

High Glucose with Insulin Induces Cell Cycle Progression and Activation of Oncogenic Signaling of Bladder Epithelial Cells Cotreated with Metformin and Pioglitazone

Metformin and pioglitazone are two commonly prescribed oral hypoglycemic agents for diabetes. Recent evidence suggests that these drugs may contribute to bladder cancer. This study investigated molecular mechanism underlying effects of metformin and pioglitazone in bladder epithelial carcinogenesis in type 2 diabetes. The cells derived from human bladder epithelial cells (HBlEpCs) were treated with metformin or pioglitazone with high glucose and insulin. Cell viability and proliferation were evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and a bromodeoxyuridine incorporation assay, respectively, while cell cycle regulatory factors and oncogene expression were analyzed using western blotting. Metformin or pioglitazone suppressed cell viability concentration and time dependently, which was reversed by exposure to high glucose with or without insulin. Prolonged exposure to high glucose and insulin enhanced cyclin D, cyclin-dependent kinase 4 (Cdk4), and Cdk2 expression and suppressed cyclin-dependent kinase inhibitors p21 and p15/16 in HBlEpC cotreated with pioglitazone and metformin. Levels of tumor suppressor proteins p53 and cav-1 were downregulated while those of the oncogenic protein as c-Myc were upregulated under high glucose and insulin supplementation in HBlEpC cotreated with pioglitazone and metformin. Prolonged exposure to high glucose with or without insulin downregulated B cell lymphoma 2-associated X (Bax) and failed to enhance the expression of extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (p38MAPK) in drug-treated cells. These results suggest that hyperglycemic and insulinemic conditions promote cell cycle progression and oncogenic signaling in drug-treated bladder epithelial cells and uncontrolled hyperglycemia and hyperinsulinemia are probably greater cancer risk factors than diabetes drugs.

Interleukin-32α induces migration of human melanoma cells through downregulation of E-cadherin

Interleukin (IL)-32α, the shortest isoform of proinflammatory cytokine IL-32, is associated with various inflammatory diseases and cancers. However, its involvement in human melanoma is not understood. To determine the effect of IL-32α in melanoma, IL-32α levels were examined in human melanoma cell lines that exhibit different migratory abilities. IL-32α levels were higher in human melanoma cell lines with more migratory ability. An IL-32α-overexpressing G361 human melanoma cell line was generated to investigate the effect of IL-32α on melanoma migration. IL-32α-overexpressing G361 cells (G361-IL-32α) exhibit an increased migratory ability compared to vector control cells (G361-vector). To identify factors involved in IL-32α-induced migration, we compared expression of E-cadherin in G361-vector and G361-IL-32α cells. We observed decreased levels of E-cadherin in G361-IL-32α cells, resulting in F-actin polymerization. To further investigate signaling pathways related to IL-32α-induced migration, we treated G361-vector and G361-IL-32α cells with PD98059, a selective MEK inhibitor. Inhibition of Erk1/2 by PD98059 restored E-cadherin expression and decreased IL-32α-induced migration. In addition, cell invasiveness of G361-IL-32α cells was tested using an in vivo lung metastasis model. As results, lung metastasis was significantly increased by IL-32α overexpression. Taken together, these data indicate that IL-32α induced human melanoma migration via Erk1/2 activation, which repressed E-cadherin expression. Our findings suggest that IL-32α is a novel regulator of migration in melanoma.

Therapeutic effect of erythroid differentiation regulator 1 (Erdr1) on collagen-induced arthritis in DBA/1J mouse

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease, and multiple inflammatory cytokines are involved in RA pathogenesis. Interleukin (IL)-18, in particular, has a significant positive correlation with RA. In this study, we investigated the effect of erythroid differentiation regulator 1 (Erdr1), which is negatively regulated by IL-18, in an animal model of inflammatory arthritis, collagen-induced arthritis (CIA) in DBA/1J mice. Treatment of mice with recombinant (r)Erdr1 significantly suppressed the severity of arthritis, histologic features of arthritic tissue, and serum levels of anti-collagen autoantibodies (IgG, IgG1, IgG2a and IgM) in CIA. In addition, IL-18 expression was reduced in the affected synovium of rErdr1-treated mice. Interestingly, Erdr1 treatment suppressed migration in contrast to the pro-migratory effect of IL-18, indicating the therapeutic effects of Erdr1 on CIA through inhibiting synovial fibroblast migration. In addition, Erdr1 inhibited activation of ERK1/2, a key signaling pathway in migration of various cell types. Taken together, these data show that rErdr1 exerts therapeutic effects on RA by inhibiting synovial fibroblast migration, suggesting that rErdr1 treatment might be an effective therapeutic approach for RA.

Cyclooxygenase-2 expression is induced by celecoxib treatment in lung cancer cells and is transferred to neighbor cells via exosomes

Lung cancer is one of most common types of cancer worldwide. Lung cancer results in a death higher rate each year compared to colon, breast and prostate cancer combined. Celecoxib is a selective inhibitor of cyclooxygenase-2 (COX‑2), an enzyme of which the expression is induced by various stimuli, such as inflammation. In addition, celecoxib triggers COX-2 loading on exosomes. Exosomes are small vesicles composed of a lipid bilayer membrane and are found in most biological fluids, such as blood breast milk and urine. In this study, we focused on exosomes containing COX-2 proteins from lung cancer cells to determine their involvement in the interaction with neighbor cells following treatment with celecoxib. We found that celecoxib induced COX-2 expression in both the cytosol and exosomes in lung cancer cells. Exosomes from celecoxib-treated lung cancer cell culture supernatant were isolated and incubated with several types of cells. The THP-1, monocytic leukemia cell line effectively absorbed COX-2 by lung cancer cell-derived exosomes. Following incubation with exosomes, the COX-2 protein level was increased in the THP-1 cells; however, COX-2 mRNA expression was not affected. Moreover, prostaglandin E2 (PGE2) and vascular endothelial growth factor (VEGF) production by THP-1 cells was increased following incubation with exosomes from celecoxib-treated lung cancer cells. Conditioned medium from THP-1 following incubation with exosomes promoted formation in EA.hy926 cells. Taken together, our findings suggest that celecoxib induces COX-2 expression in lung cancer cells, and that highly expressed COX-2 in exosomes can be transferred to other cells.

RPS27a enhances EBV-encoded LMP1-mediated proliferation and invasion by stabilizing of LMP1

Epstein-Barr virus (EBV)-encoded latent membrane protein 1 (LMP1) is an oncoviral protein that plays a pivotal role in EBV-induced oncogenic transformation. The function of LMP1 in EBV-induced oncogenesis has been well studied. However, the molecular mechanisms underlying LMP1 protein stability remain poorly understood. In this study, we found that ribosomal protein s27a (RPS27a) regulates LMP1 stability by a tandem affinity purification analysis. RPS27a interacts directly with LMP1 in vitro and in vivo. Furthermore, overexpression of RPS27a increases the half-life of LMP1 in 293T cells, whereas downregulation of RPS27a using lentiviral shRNA technology accelerates the decrease in LMP1 protein level in EBV-transformed B cells. We show that LMP1 ubiquitination via the proteasome is completely inhibited by overexpression of RPS27a. RPS27a also enhances LMP1-mediated proliferation and invasion, suggesting that RPS27a interacts with LMP1 and stabilizes it by suppressing proteasome-mediated ubiquitination. These results suggest that RSP27a could be a potential target in EBV-infected LMP1-positive cancer cells.

Combination treatment with erlotinib and ampelopsin overcomes erlotinib resistance in NSCLC cells via the Nox2-ROS-Bim pathway

Erlotinib, a tyrosine kinase inhibitor (TKI) of epidermal growth factor receptor (EGFR), has been shown to have a dramatic effect in non-small cell lung cancer (NSCLC) patients with EGFR mutation. However, the presence of primary resistance or acquired resistance to EGFR-TKI is the most common reason for switching to other anti-cancer agents. Even though there are newer agents that have activity in the presence of the T790M mutation, identification of potential agents that could overcome resistance to EGFR-TKI is still needed for the treatment of NSCLC patients. In this study, we used erlotinib-resistant NSCLC cell lines to investigate the effects of combination treatment with erlotinib and ampelopsin. To determine the effect of Nox2 and Bim on the combined treatment with erlotinib and ampelopsin-induced cell death, we transfected with Nox2 or Bim specific siRNA and performed with western blot assay for evaluation of its expression. Combined treatment with erlotinib and ampelopsin at non-cytotoxic concentrations significantly induced caspase-dependent cell death in erlotinib-resistant NSCLC cells. Furthermore, cell death resulted in the accumulation of reactive oxygen species (ROS) through upregulation of nicotinamide adenine dinucleotide phosphate oxidase 2 (Nox2) expression, a direct source of ROS. The expression level of Bim increased with combination treatment, but not with either treatment alone. Here in this study, we demonstrate that the combination of erlotinib and ampelopsin induces cell death via the Nox2-ROS-Bim pathway, and ampelopsin could be used as a novel anti-cancer agent combined with EGFR-TKI to overcome resistance to erlotinib in EGFR-mutant NSCLC.

Vandetanib and ADAM inhibitors synergistically attenuate the pathological migration of EBV-infected retinal pigment epithelial cells by regulating the VEGF-mediated MAPK pathway

The extracellular signals induced by vascular endothelial growth factor (VEGF) are implicated in choroidal neovascularization (CNV) and thus, are associated with vision-limiting complications in the human retina. Vandetanib is an oral anticancer drug that selectively inhibits the activities of VEGF receptor and epidermal growth factor receptor tyrosine kinase; however, the effects of vandetanib on VEGF in retinal pigment epithelial (RPE) cells have not yet been studied. In the present study, a combined treatment of vandetanib and a disintegrin and metalloproteinase (ADAM) protein inhibitors were used to assess the regulation of Epstein-Barr virus (EBV)-infected ARPE19 cells (ARPE19/EBV) migration as a model of CNV. Vandetanib suppressed the expression of the mesenchymal markers ADAM10 and ADAM17 in ARPE19/EBV cells, and also upregulated epithelial cell markers of the RPE cells, E-cadherin and N-cadherin. The migratory activity of ARPE19/EBV induced by VEGF was efficiently blocked by vandetanib. Furthermore, co-treatment with vandetanib and an ADAM10 inhibitor (GI254023X) or ADAM17 inhibitor (Marimastat) synergistically prevented migration and the expression of vimentin, Snail and α-smooth muscle actin by regulating extracellular signal-regulated kinase and p38 mitogen-activated protein kinase. These results suggest that a combination treatment of vandetanib and ADAM inhibitors may be developed as a novel therapeutic regimen to control retina neovascular disease.

Combined treatment with vitamin C and sulindac synergistically induces p53- and ROS-dependent apoptosis in human colon cancer cells

Sulindac has anti-neoplastic properties against colorectal cancers; however, its use as a chemopreventive agent has been limited due to toxicity and efficacy concerns. Combinatorial treatment of colorectal cancers has been attempted to maximize anti-cancer efficacy with minimal side effects by administrating NSAIDs in combination with other inhibitory compounds or drugs such as l-ascorbic acid (vitamin C), which is known to exhibit cytotoxicity towards various cancer cells at high concentrations. In this study, we evaluated a combinatorial strategy utilizing sulindac and vitamin C. The death of HCT116 cells upon combination therapy occurred via a p53-mediated mechanism. The combination therapeutic resistance developed in isogenic p53 null HCT116 cells and siRNA-mediated p53 knockdown HCT116 cells, but the exogenous expression of p53 in p53 null isogenic cells resulted in the induction of cell death. In addition, we investigated an increased level of intracellular ROS (reactive oxygen species), which was preceded by p53 activation. The expression level of PUMA (p53-upregulated modulator of apoptosis), but not Bim, was significantly increased in HCT116 cells in response to the combination treatment. Taken together, our results demonstrate that combination therapy with sulindac and vitamin C could be a novel anti-cancer therapeutic strategy for p53 wild type colon cancers.

Effects of Memantine on Aminoglycoside-Induced Apoptosis of Spiral Ganglion Cells in Guinea Pigs

Objective

To explore whether memantine, an N-methyl-D-aspartate receptor antagonist, exerts a neuroprotective effect against apoptosis of spiral ganglion cells (SGCs) induced by gentamicin.

Study Design

An animal experiment.

Setting

Dong-A University College of Medicine, Busan, Korea.

Subjects and Methods

Gentamicin was injected into the left cochleae of guinea pigs to induce apoptosis of SGCs; the contralateral cochleae served as controls. Memantine was intraperitoneally injected 12 hours and 1 hour prior to gentamicin injection. At 1 week after gentamicin and/or memantine injection, the cochleae were removed and stained with hematoxylin and eosin to evaluate morphologic changes and apoptosis. Western blotting was performed to measure FasL expression and the extent of caspase activation in SGCs.

Results

SGC numbers remained stable after memantine treatment. Western blotting showed that FasL expression and activation of caspases 3, 8, and 9 were reduced in SGCs after memantine treatment.

Conclusion

Memantine attenuated the gentamicin-induced apoptosis of SGCs in guinea pigs. Moreover, memantine may affect Fas-FasL signaling in the receptor-mediated apoptotic pathway and caspase activation involved in the receptor-mediated and mitochondrial apoptotic pathways.

Expression of ADAM17 and ADAM10 in nasal polyps

BACKGROUND

The "a disintegrin and metalloproteases" (ADAMs) are a multifunctional gene family that contribute to the homeostasis of the extracellular matrix, transduction of specific intracellular signals, organogenesis, inflammation, tissue remodeling, adhesion, and cell migration. ADAM17 is the best-characterized of the "sheddases," and its putative substrates are widespread, including various inflammatory modulators. ADAM10 is the most similar to ADAM17 in terms of protein sequence and the structural properties of their catalytic domains. The objective of this work was to assess the roles of ADAM17 and ADAM10 in nasal polyps (NPs) by measuring their expression.

METHODS

The expression of ADAM10 and 17 was investigated in NPs at endonasal sinus surgery (n = 15) and compared with that in inferior turbinate mucosa samples obtained from nonallergic hypertrophic rhinitis patients (n = 15). Tissue samples were analyzed by real-time polymerase chain reaction (PCR), Western blotting, and immunohistochemical staining.

RESULTS

The ADAM17 messenger RNA (mRNA) and protein levels were significantly higher in the inferior turbinate than in NPs (p < 0.05). The ADAM10 mRNA and protein levels did not differ significantly between NPs and inferior turbinates (p > 0.05). ADAM10 and ADAM17 were expressed primarily in inflammatory cells, submucosal glandular cells, and lining epithelial cells.

CONCLUSION

ADAM17 may contribute to the development of NPs in contrast to ADAM10, based on their expression patterns. It may be important to discover the role of ADAM17 in the development of NP and helpful to examine the specific mechanism of the development of NPs.

Regulation of ADAM10 and ADAM17 by Sorafenib Inhibits Epithelial-to-Mesenchymal Transition in Epstein-Barr Virus-Infected Retinal Pigment Epithelial Cells

PURPOSE

The a-disintegrin-and-metalloprotease (ADAM) family proteins are widely expressed in the different layers of the retina throughout development. The effect of ADAM proteins on the epithelial-to-mesenchymal transition (EMT) in proliferative vitreoretinopathy (PVR) or AMD is yet to be elucidated. In this study we used Epstein-Barr virus (EBV)-transformed adult retinal pigment epithelial (ARPE) cells to investigate how sorafenib, a multikinase inhibitor, modulates ADAM proteins to control EMT.

METHODS

Epithelial to mesenchymal transition and related mechanisms in EBV-infected ARPE cells were determined by RT-PCR, Western blot, invasion assay, ELISA assay, and gene silencing with siRNA.

RESULTS

Mesenchymal-like ARPE/EBV cells exhibited considerably increased cellular migration and invasion compared with ARPE cells and produced EMT-related cytokines. Sorafenib significantly inhibited production of TGF-β1, VEGF, IL-6, IL-8, MCP-1, and TNF-α and blocked the activation of migration-related signaling molecules, such as HIF-1α, p-STAT3, MMP2, and Ang-1. The expression of mature ADAM10, ADAM17, and cleaved Notch 1 proteins in ARPE/EBV cells was downregulated after treatment with sorafenib through the regulatory activity of nardilysin (NRD-1). Gene silencing of NRD-1 in ARPE/EBV cells attenuated secretion of EMT-related cytokines and expression of ADAM10 and 17 and upregulated epithelial markers.

CONCLUSIONS

Sorafenib controls the mesenchymal characteristics of EBV-infected ARPE cells. Nardilysin and ADAM family proteins might be new targets for the prevention or control of EMT in retinal diseases.

Pre-stimulation of CD81 expression by resting B cells increases proliferation following EBV infection, but the overexpression of CD81 induces the apoptosis of EBV-transformed B cells

Hepatitis C virus (HCV) E2 protein binds to CD81, which is a component of the B cell co-stimulatory complex. The E2-CD81 interaction leads to B cell proliferation, protein tyrosine phosphorylation and to the hypermutation of immunoglobulin genes. Epidemiological studies have reported a high prevalence of B cell non-Hodgkin lymphoma (NHL) in HCV-positive patients, suggesting a potential association between HCV and Epstein-Barr virus (EBV) in the genesis of B lymphocyte proliferative disorders. In the present study, in order to investigate the association between EBV and HCV in B cells, we created an in vitro EBV-induced B cell transformation model. CD81 was gradually overexpressed during transformation by EBV. B cells isolated from HCV-positive patients grew more rapidly and clumped together earlier than B cells isolated from healthy donors following EBV infection. Pre-stimulation of CD81 expressed by resting B cells with anti-CD81 monoclonal antibody (mAb) or HCV E2 accelerated the generation of lymphoblastoid cell lines (LCLs) by EBV infection. These cells proliferated prominently through the early expression of interleukin-10 and intracellular latent membrane protein (LMP)-l. By contrast, the overexpression of CD81 on EBV-transformed B cells by anti-CD81 mAb or HCV E2 protein induced apoptosis through reactive oxygen species (ROS)-mediated mitochondrial dysfunction. These results suggest that the engagement of CD81 expressed by B cells has differential effects on B cell fate (proliferation or apoptosis) according to EBV infection and the expression level of CD81.

Expression profile of ADAM10 and ADAM17 in allergic rhinitis

BACKGROUND

A disintegrin and metalloprotease (ADAM) is a multifunctional gene family that contributes to the homeostasis of the extracellular matrix, transduction of specific intracellular signals, organogenesis, inflammation, tissue remodeling, adhesion, and cell migration. ADAM17 is the best characterized sheddase, with widespread putative substrates, including various inflammatory modulators. ADAM10 is the most similar ADAM to ADAM17 in terms of both protein sequence and the structural properties of their catalytic domains. The objective of this work was to assess the expression of ADAM10 and ADAM17 in allergic rhinitis to gain insight into their respective roles.

METHODS

The expression of ADAM10 and ADAM17 was investigated in the nasal mucosa under allergic and nonallergic conditions. Tissue samples were evaluated by reverse-transcription polymerase chain reaction (RT-PCR) and Western blotting, and data were analyzed semiquantitatively with densitometry.

RESULTS

The ADAM17 messenger RNA (mRNA) level was significantly (p < 0.001) lower in the allergic nasal mucosa than in the nonallergic nasal mucosa, whereas the ADAM10 mRNA level was significantly (p < 0.001) lower in the nonallergic nasal mucosa. The ADAM17 protein levels were also significantly (p < 0.001) lower in the allergic nasal mucosa, whereas the ADAM10 protein levels were lower in the nonallergic nasal mucosa (p = 0.002).

CONCLUSION

Decreased expression of ADAM17 and increased expression of ADAM10 may contribute to the development of allergic rhinitis through unknown pathways. We suggest that understanding the expression profile of ADAM17 and ADAM10 might help to elucidate the mechanism of allergic rhinitis.

Delivery of miR-155 to retinal pigment epithelial cells mediated by Burkitt's lymphoma exosomes

Exosomes are extracellularly secreted vesicles ranging from 40 to 100 nm in diameter that are thought to play important roles in intercellular communication. Exosomes contain numerous proteins, RNA, and lipids that can affect the status of recipient cells under various pathological conditions. MicroRNAs (miRNAs) are small non-coding RNAs that play a major role in post-transcriptional gene silencing by interacting with the 3'-untranslated regions of target genes. Epstein-Barr virus (EBV) has been reported to induce sustained elevation of cellular miRNAs such as miR-155. We hypothesized that miRNAs delivered by exosomes might affect the angiogenesis of retinal pigment epithelial (RPE) cells. Here, we demonstrated that co-culture of EBV-positive Burkitt's lymphoma (BL) cells (Raji) with retinal pigment epithelial (ARPE-19) cells increased the level of miR-155 in recipient cells whereas no major difference was detected for co-culture with EBV-negative BL cells (Ramos). Isolated Raji exosomes increased transcriptional and translational levels of VEGF-A in ARPE-19 cells, which was reversely correlated with von Hippel-Lindau expression. A human umbilical vein endothelial cell tube formation assay showed that delivery of ectopic miR-155 rendered ARPE-19 cells proangiogenic. Our results demonstrate that sustained accumulation of miR-155 mediated by exosomes might affect remote recipient cells such as retinal pigment epithelial cells.

Combining CAL-101 with Celecoxib Enhances Apoptosis of EBV-transformed B-Cells Through MAPK-induced ER Stress

BACKGROUND

Phosphoinositide-3 kinase (PI3K) inhibition attenuates proliferation and survival in B-cell malignancies. Celecoxib induces endoplasmic reticulum (ER) stress-induced apoptosis via a cyclo-oxgenase-2 (COX2)-independent manner in certain types of cancer cells. In the present study, we assessed the effects of combinations of drugs with a p110δ-specific inhibitor, CAL-101, and celecoxib to induce apoptosis in Epstein-Barr virus (EBV)-transformed B-cells and non-Hodgkin's lymphoma (NHL) cells.

MATERIALS AND METHODS

The apoptotic effect of combination treatment with CAL-101 and celecoxib on B-cell malignancies was determined by flow cytometry and immunoblotting.

RESULTS

Exposure to CAL-101 and celecoxib significantly increased apoptosis, which was accompanied by the inactivation of AKT, Ras homolog gene family, member A (RHOA), Rho-associated coiled-coil containing protein kinase 1 (ROCK1), and ROCK2 as well as up-regulation of Phosphatase and tensin homolog (PTEN). Co-treatment with CAL-101 and celecoxib triggered the ER stress response and the down-regulation of BCL2 and BCL-XL. SB203580, SP600125, and salubrinal effectively inhibited apoptosis and attenuated expression of phosphorylated protein kinase RNA-like endoplasmic reticulum kinase (PERK) and CCAAT-enhancer-binding protein homologous protein (CHOP). Levels of apoptosis signal-regulating kinase 1 (ASK1) were also increased after treatment with CAL-101 and celecoxib.

CONCLUSION

The apoptosis of EBV-transformed B-cells and NHL cells caused by CAL-101 and celecoxib might be related to inhibiting the RHOA/ROCK pathway and might also be associated with mitogen-activated protein kinase (MAPK)-mediated ER stress.

TLR3/TRIF signalling pathway regulates IL-32 and IFN-β secretion through activation of RIP-1 and TRAF in the human cornea

Toll-like receptor-3 (TLR3) and RNA helicase retinoic-acid-inducible protein-1 (RIG-I) serve as cytoplasmic sensors for viral RNA components. In this study, we investigated how the TLR3 and RIG-I signalling pathway was stimulated by viral infection to produce interleukin (IL)-32-mediated pro-inflammatory cytokines and type I interferon in the corneal epithelium using Epstein-Barr virus (EBV)-infected human cornea epithelial cells (HCECs/EBV) as a model of viral keratitis. Increased TLR3 and RIG-I that are responded to EBV-encoded RNA 1 and 2 (EBER1 and EBER2) induced the secretion of IL-32-mediated pro-inflammatory cytokines and IFN-β through up-regulation of TRIF/TRAF family proteins or RIP-1. TRIF silencing or TLR3 inhibitors more efficiently inhibited sequential phosphorylation of TAK1, TBK1, NF-κB and IRFs to produce pro-inflammatory cytokines and IFN-β than RIG-I-siRNA transfection in HCECs/EBV. Blockade of RIP-1, which connects the TLR3 and RIG-I pathways, significantly blocked the TLR3/TRIF-mediated and RIG-I-mediated pro-inflammatory cytokines and IFN-β production in HCECs/EBV. These findings demonstrate that TLR3/TRIF-dependent signalling pathway against viral RNA might be a main target to control inflammation and anti-viral responses in the ocular surface.

Hair-growth stimulation by conditioned medium from vitamin D3-activated preadipocytes in C57BL/6 mice

AIMS

Recently, immature adipocyte lineage cells have been suggested as a potential hair-growth stimulator. Diverse studies have been attempted to find methods for the preconditioning of immature adipocyte lineage cells. The present study investigates the effect of conditioned medium (CM) from vitamin D3 (Vd3) pre-activated preadipocytes on hair-growth ability.

MAIN METHODS

To test the effect of CM from Vd3 pre-activated preadipocytes on hair-growth efficiency in mice, we compared the differences in hair regenerated after injecting CM from mouse preadipocytes pre-activated with or without Vd3. Next, to determine the regulating factors, the VEGF level was measured by ELISA and angiogenesis level was evaluated by IHC. Finally, the signaling mechanism was investigated by inhibitor kinase assay and western blotting.

KEY FINDINGS

The CM from Vd3 pre-activated preadipocyte injection markedly promoted the ability of hair regeneration in mice. The VEGF levels were increased by Vd3 treatment in vitro and the CM from Vd3 pre-activated preadipocytes significantly increased the angiogenesis in vivo, suggesting the involvement of angiognensis in the hair regeneration induced by CM from pre-activated preadipocytes. In signaling study, Vd3-enhanced VEGF production was reduced by an ERK1/2 inhibitor and the level of ERK1/2 phosphorylation was increased by treatment with Vd3.

SIGNIFICANCE

This has been the first report on CM from Vd3 pre-activated preadipocyte displaying stimulatory effects on hair growth via the enhancement of angiogenesis in a hairless-induced C57BL/6 mice.

ERDR1 enhances human NK cell cytotoxicity through an actin-regulated degranulation-dependent pathway

Erythroid differentiation regulator 1 (ERDR1), which is a stress-related survival factor, exhibits anti-cancer effects against melanoma. However, the function of ERDR1 on immune cells has not been examined. We investigated whether ERDR1 regulates the cytotoxic ability of human natural killer (NK) cells, which are known as innate effector lymphocytes. In this study, treatment with recombinant ERDR1 resulted in enhanced NK cell cytotoxicity through the secretion of lytic granules. Furthermore, actin modulation was involved in the ERDR1-enhanced NK cell cytotoxicity. ERDR1 stimulated actin accumulation at the immunological synapse, which was induced by the activation of Vav-1 in NK cells. These findings suggest new insight into the function of ERDR1 function in the human immune system.

Apoptotic signaling through reactive oxygen species in cancer cells

Reactive oxygen species (ROS) take part in diverse biological processes like cell growth, programmed cell death, cell senescence, and maintenance of the transformed state through regulation of signal transduction. Cancer cells adapt to new higher ROS circumstance. Sometimes, ROS induce cancer cell proliferation. Meanwhile, elevated ROS render cancer cells vulnerable to oxidative stress-induced cell death. However, this prominent character of cancer cells allows acquiring a resistance to oxidative stress conditions relative to normal cells. Activated signaling pathways that increase the level of intracellular ROS in cancer cells not only render up-regulation of several genes involved in cellular proliferation and evasion of apoptosis but also cause cancer cells and cancer stem cells to develop a high metabolic rate. In over the past several decades, many studies have indicated that ROS play a critical role as the secondary messenger of tumorigenesis and metastasis in cancer from both in vitro and in vivo. Here we summarize the role of ROS and anti-oxidants in contributing to or preventing cancer. In addition, we review the activated signaling pathways that make cancer cells susceptible to death.

Silencing of galectin-3 represses osteosarcoma cell migration and invasion through inhibition of FAK/Src/Lyn activation and β-catenin expression and increases susceptibility to chemotherapeutic agents

Galectin-3 is involved in tumor cell proliferation, adhesion, angiogenesis and metastasis. Galectin-3 promotes β-catenin/Wnt signaling, and β-catenin-related oncogenesis has been frequently reported in osteosarcoma. However, the correlation between galectin-3 and β‑catenin signaling in osteosarcoma is poorly defined. We hypothesized that galectin-3 may control the migration and invasion of cancer cells and that silencing of galectin-3 would therefore, suppress motility in osteosarcoma cells. In the present study, we show that galectin-3 silencing in cultured human osteosarcoma cells had decreased cell migration and invasion capabilities; reduced the expression and activation of FAK, Src, Lyn, PI3K/Akt, ERK1/2 and β-catenin, which are key mediators of invasion; inhibited the expression and secretion of VEGF, MCP-1, IL-8, IL-6, MMP2/9 and phospho-Stat3; and potentiated sensitivity to cisplatin. Our results suggest that galectin-3 may be a feasible therapeutic target for osteosarcoma.

MiR-9 regulates the post-transcriptional level of VEGF165a by targeting SRPK-1 in ARPE-19 cells

PURPOSE

To investigate the effect of the overexpression of miRNA-9 to the ratio of pro- and anti-angiogenic isoforms of vascular endothelial growth factor (VEGF) in human retinal pigment cells (ARPE-19).

METHODS

Oxidative stress was induced to ARPE-19 cells by 4-hydroxynonenal (4-HNE), tert-butyl hydroperoxide (t-BH), and hypoxia chamber with 1% O₂. Expression patterns of miRNAs were validated by qPCR. Relative mRNA levels of VEGF and PEDF were measured by semi-quantitative PCR. After the transfection of miR-9 mimic and inhibitor, transcriptional levels of VEGF165a, VEGF 165b, and SRPK-1 were measured by qPCR.

RESULTS

We demonstrated that miR-9 expression is decreased in ARPE-19 human retinal pigment cells under hypoxic stress induced by 4-HNE, a lipid peroxidation end-product. We observed that miR-9 mimic transfection of ARPE-19 inhibited one of its targets, serine-arginine protein kinase-1 (SRPK-1), modulating the transcriptional level of VEGF165b. Transfection of miR-9 reduced the alternative splicing of VEGF165a mRNA in ARPE-19 cells under hypoxic conditions, suggesting that miR-mediated regulation of alternative splicing could be a potential therapeutic target in neovascular pathologies.

CONCLUSIONS

Hypoxic stress decreased the miR-9 level in ARPE-19 cells, which increased the transcriptional level of SRPK-1, resulting in alternative splicing shift to pro-angiogenic isoforms of VEGF165 in human retinal pigment epithelial cells.

Silencing of PKCη induces cycle arrest of EBV(+) B lymphoma cells by upregulating expression of p38-MAPK/TAp73/GADD45α and increases susceptibility to chemotherapeutic agents

PKCη is involved in proliferation, differentiation, and drug resistance. However, PKCη function in EBV(+) B lymphoma remains poorly understood. Gene silencing of PKCη through siRNA knockdown inhibited cellular proliferation, induced cell cycle arrest in G0/G1 and G2/M phases, and sensitized cells to chemotherapeutic drugs. Upon PKCη knockdown, expression levels of p21, GADD45α, and TAp73 were all increased, whereas expression levels of CDK2, CDK4, CDK6, cyclin E, cyclin B1, and cdc2 were all downregulated. PKCη silencing also activated p38-MAPK, which in turn contributed to the expression of cell cycle arrest-related molecules. These results suggest that siRNA-mediated silencing of PKCη can be a potent tool to complement existing chemotherapy regimens for treating EBV(+) B lymphoma.

The Epstein-Barr virus causes epithelial-mesenchymal transition in human corneal epithelial cells via Syk/src and Akt/Erk signaling pathways

PURPOSE

Although Epstein-Barr virus (EBV)-associated keratitis is rare, it can cause acute corneal necrosis and neovascularization. We aimed to examine the signaling mechanism by which EBV causes epithelial-mesenchymal transition (EMT) in human corneal epithelial cells (HCECs) in vitro.

METHODS

The cellular response to EBV was assessed by real-time PCR, Western blot, migration assay, invasion assay, inhibitor assay, and ELISA assay.

RESULTS

A model of EBV-induced EMT was established in HCECs. The EBV induced morphologic changes in the cells; the loss of epithelial markers E-cadherin, ZO-1, and β-catenin; and an increase in the mesenchymal markers N-cadherin, Vimentin, Snail, and TCF8/Zeb1. The EBV infection also led to the nuclear translocation of Snail and TCF8/Zeb1; enhanced the secretion of IL-6, IL-8, VEGF, TGF-β1, TNF-α, and MCP-1; and upregulated the expression of MMP2 and MMP9. The EBV-infected HCECs exhibited increased migration and invasiveness compared to uninfected HCECs. We measured the involvement of Syk, Src, PI3K/Akt, and Erk signaling, but not Smad, in EMT by EBV-induced TGF-β1. We demonstrated that treatment with TGF-β1, TGF-β receptors, Syk, or Src inhibitor blocked TGF-β1, Syk, or Src signaling activation, and EMT development by EBV. Moreover, these inhibitors prevented PI3K/Akt and Erk activation.

CONCLUSIONS

An EBV infection in HCECs can lead to a mesenchymal fibroblast-like morphology, and cause EMT through the activation of PI3K/Akt and Erk by TGF-β1-mediated Syk and Src signaling. This phenomenon may have implications for EBV-associated keratitis and molecular approaches to treatment.

Sequential treatment of HPV E6 and E7-expressing TC-1 cells with bortezomib and celecoxib promotes apoptosis through p-p38 MAPK-mediated downregulation of cyclin D1 and CDK2

Interruption of the cell cycle is accompanied by changes in several related molecules that result in the activation of apoptosis. The present study was performed to verify the apoptotic effects of sequential treatment with bortezomib and celecoxib in TC-1 cells expressing the human papillomavirus (HPV) E6 and E7 proteins. In TC-1 cells sequentially treated with bortezomib and celecoxib, apoptosis was induced through decreased expression of signal transducer and activator of transcription-3 (STAT3), cyclin D1 and cyclin-dependent kinase (CDK) 2, which are major regulators of the G0/G1 cell cycle checkpoint. In addition, increased levels of p21, CHOP, BiP and p-p38 MAPK were identified in these cells. The treatment-induced apoptosis was effectively inhibited by treatment with SB203580, an inhibitor of p-p38. Moreover, the growth of tumors sequentially treated with bortezomib and celecoxib was retarded compared to the growth of tumors exposed to a single treatment with either bortezomib or celecoxib in vivo. We demonstrated that sequential treatment with bortezomib and celecoxib induced apoptosis via p-p38-mediated G0/G1 cell cycle arrest and endoplasmic reticulum (ER) stress. Sequential treatment with these two drugs could therefore be a useful therapy for cervical cancer.

Paclitaxel-exposed ovarian cancer cells induce cancer‑specific CD4+ T cells after doxorubicin exposure through regulation of MyD88 expression

Ovarian cancer has the highest mortality rate among gynecological malignancies due to high chemoresistance to the combination of platinum with taxane. Immunotherapy against ovarian cancer is a promising strategy to develop from animal-based cancer research. We investigated changes in the immunogenicity of paclitaxel-exposed ovarian cancer cells following exposure to other chemotherapeutic drugs. Murine ovarian surface epithelial cells (MOSECs) showed some resistance to paclitaxel, a first-line therapy for ovarian cancer. However, MOSECs pre-exposed to paclitaxel died through apoptosis after incubation with doxorubicin or cisplatin for 2 h. Injected into mice, the paclitaxel-exposed MOSECs post-treated with doxorubicin induced more MOSEC-specific CD4(+) T cells and extended survival for a greater time than MOSECs treated with paclitaxel alone; and bone marrow-derived dendritic cells (BMDCs) expressed higher levels of co-stimulatory molecules and produced IL-12 after co-culture with paclitaxel-exposed MOSECs treated with doxorubicin. We also observed that in paclitaxel-exposed MOSECs treated with doxorubicin, but not cisplatin, the expression of MyD88 and related target proteins decreased compared to paclitaxel-exposed MOSECs only, while in BMDCs co-cultured with these MOSECs the expression of myeloid differentiation primary response gene 88 (MyD88) increased. These findings suggest that paclitaxel pre-exposed cancer cells treated with doxorubicin can induce significant apoptosis and a therapeutic antitumor immune response in advanced ovarian cancer.

Nasal polyp chitinolytic activity associated with smoking or allergy

BACKGROUND

Cells of the innate immune system that are implicated in allergy and immunity bind to chitin during tissue infiltration in a process negatively regulated by vertebrate chitinases. Both acidic mammalian chitinase (AMCase) and chitotriosidase (ChT) exert chitinolytic activity. The levels of activities of these enzymes in nasal polyps (NPs) of subjects who smoke or who suffer from allergies are unknown. In the present work, we measured the activities of AMCase and ChT in NPs of smokers and allergic subjects.

METHODS

We report a prospective cohort study in a tertiary care facility. AMCase and ChT activities of NPs were measured in buffers of several pH values using the fluorogenic substrate 4-methylumbelliferyl-β-d-N,N',N″-triacetyl-chitotriose.

RESULTS

The activities of AMCase and ChT in NPs did not differ significantly among smokers, nonsmokers, and ex-smokers. AMCase and ChT activities were significantly higher in NPs of allergic subjects than in NPs of those who did not suffer from allergy.

CONCLUSION

Increased levels of chitinolytic activities in NPs were associated with the allergic rhinitis. We suggest that control of such rhinitis may help to prevent the development and growth of NPs.

ROS-mediated JNK/p38-MAPK activation regulates Bax translocation in Sorafenib-induced apoptosis of EBV-transformed B cells

Sorafenib (SRF) is a multi-kinase inhibitor that has been shown to have antitumor activity against several types of cancers, but the effect of SRF on EBV-transformed B cells is unknown. We report that SRF can induce the apoptosis of EBV-transformed B cells through JNK/p38-MAPK activation. SRF triggered the generation of reactive oxygen species (ROS), translocation of Bax into the mitochondria, disruption of mitochondrial membrane potential, activation of caspase-9, caspase-3 and PARP, and subsequent apoptosis. Moreover, we found that SRF exposure activated the phosphorylation of JNK and p38-MAPK and suppressed the phosphorylation of PI3K-p85 and Akt. N-acetyl-l-cysteine (NAC) inhibited the activation of JNK and p38-MAPK. SP600125 and SB203580 blocked apoptosis and mitochondrial membrane disruption but did not affect ROS production after SRF treatment. These findings provide novel insights into the molecular mechanisms driving SRF-mediated cell death and suggest that SRF could be a potential therapeutic drug for the treatment of EBV-related malignant diseases.

Synthesis and solvent-dependent photochromic reactions of porphyrin-spiropyran hybrid compounds

Porphyrin(Por)-spiropyran(SP) hybrid compounds, including Por-SP dyad, Por-SP2 triad, and Por-SP4 pentad, were prepared and characterized by (1)H NMR, MALDI-TOF MS and UV-Vis spectroscopies. Upon 350 nm UV irradiation of Por-SPn (n=1, 2, 4) in dichloromethane, unusual red-shifted absorption spectra were observed with the colour change from pink into green. Probably due to the protonation of core nitrogens in porphyrin ring, their absorption maxima in dichloromethane were shifted from 418 (Soret band), 515, 550, 590, 645 (four Q bands) nm into 450 and 665 nm. Also, fluorescence maxima were also shifted from 650 and 715 nm to 692 nm. In the other hands, upon irradiation with 350nm UV light in THF, the colour changed from pink into violet and absorption band at 590 nm increased and the fluorescence spectra showed the decrease of 650 and 715 nm bands and increase of 600-640 nm band, due to the normal ring-opening reaction of spiropyran moiety into merocyanine. In the dark, original absorption and fluorescence spectra were recovered very slowly in dichloromethane, but quickly in THF. The reversible photochromic reactions of Por-SPn (n=1, 2, 4) in dichloromethane and THF were investigated by observing absorption and fluorescence spectral changes during UV irradiation or standing in the dark.