Optimization of adipose tissue-derived mesenchymal stromal cells transplantation for bone marrow repopulation following irradiation.

BACKGROUND: Bone marrow (BM) suppression is one of the most common side effects of radiotherapy and the primary cause of death following exposure to irradiation. Despite concerted efforts, there is no definitive treatment method available. Recent studies have reported using mesenchymal stromal cells (MSCs), but their therapeutic effects are contested. AIM: We administered and examined the effects of various amounts of adipose-derived MSCs (ADSCs) in mice with radiation-induced BM suppression. METHODS: Mice were divided into three groups: Normal control group, irradiated (RT) group, and stem cell-treated group following whole-body irradiation (WBI). Mouse ADSCs (mADSCs) were transplanted into the peritoneal cavity either once or three times at 5 × 105 cells/200 µL. The white blood cell count and the levels of, plasma cytokines, BM mRNA, and BM surface markers were compared between the three groups. Human BM-derived CD34+ hematopoietic progenitor cells were co-cultured with human ADSCs (hADSCs) or incubated in the presence of hADSCs conditioned media to investigate the effect on human cells in vitro. RESULTS: The survival rate of mice that received one transplant of mADSCs was higher than that of mice that received three transplants. Multiple transplantations of ADSCs delayed the repopulation of BM hematopoietic stem cells. Anti-inflammatory effects and M2 polarization by intraperitoneal ADSCs might suppress erythropoiesis and induce myelopoiesis in sub-lethally RT mice. CONCLUSION: The results suggested that an optimal amount of MSCs could improve survival rates post-WBI.

Conditioned secretome of adipose-derived stem cells improves dextran sulfate sodium-induced colitis in mice.

BACKGROUND: Inflammatory bowel diseases (IBD) is related to uncontrolled immune response. Currently, there is no successful treatment for significant improvement in IBD. Stem cells display their therapeutic effects through their repopulating capacity or secreting factors. AIM: To investigate the effects of conditioned mouse adipose-derived stem cells (mADSCs) secretome on colitis-induced mice. METHODS: mADSCs were isolated from adipose tissue of C57BL/6 mice. Conditioned mADSCs secrectome was obtained by culturing of mADSCs with lipopolysaccharides (LPS, 1 µg/mL) for 24 h. Acute colitis was induced by 2% dextran sulfate sodium (DSS) drinking water for 7 d and then normal drinking water for 4 d. The mice were treated with normal culture medium (NM group), conditioned mADSCs secretome (CM group) or mADSCs (SC group). The length of colon and histopatholgy of colon tissues were evaluated. The mRNA expression levels of inflammatory cytokines in colon tissue and the serum interleukin (IL)-6 levels were determined. RESULTS: The isolated mADSCs maintained the mADSCs specific gene expression profiles during experiment. The conditioned mADSCs secretome released by the treatment of mADSCs with LPS contained mainly inflammatory chemokines, colony-stimulating factors and inflammatory cytokines. The loss of body weight and reduction in colon length were ameliorated in the CM group. The conditioned mADSCs secretome reduced the histological score in colon tissue. The expression of IL-1b and IL-6 mRNAs in colon tissues significantly inhibited in the CM group compared to SC group and NM group, respectively. The elevation of serum IL-6 levels was also ameliorated in the CM group. These results indicate that the conditioned mADSCs secretome suppressed the synthesis of inflammatory cytokines in damaged colon tissue and the elevation of serum IL-6 concentration in DSS-induced mice. CONCLUSION: Conditioned mADSCs secretome might play regenerative roles by the suppression of IL-6 in serum and tissue during acute colitis, and may be more effective than stem cells themselves in the regeneration of colon tissue.

Topical cell-free conditioned media harvested from adipose tissue-derived stem cells promote recovery from corneal epithelial defects caused by chemical burns.

Corneal chemical burns can lead to blindness following serious complications. As most of these complications are caused by failure of reepithelization during the acute phase, treatment at this stage is critical. Although there have been some studies on corneal injury recovery using adipose tissue-derived stem cells (ADSCs), none has reported the effect of topical cell-free conditioned culture media (CM) derived from ADSCs on corneal epithelial regeneration. Here, the best conditions for CM were selected and used for in vitro and in vivo experiments. Corneal burn in rats was induced using 100% alcohol. The chosen CM was administered to corneal burn rats (CM-treated [CT] group) four times a day for three days and this group was compared with the normal control and corneal burn (CB) groups. Biomicroscopic fluorescence images and the actual physical corneas were taken over time and used for analysis. mRNA levels of hepatocyte growth factor and epidermal growth factor (EGF) were significantly increased, whereas those of vascular endothelial growth factor, interleukin (IL)-1ß, IL-6, IL-10, and matrix metalloproteinase-9 were significantly decreased in the CT group compared with those in the CB group. The numbers of proliferating cell nuclear antigen- and zonular occludens-1-positive cells in the CT group were significantly higher than those in the CB group. The macrophage-infiltrating corneas in the CT group expressed significantly more of the M2 marker arginase than corneas in the CB group. Optimal CM (× 0.5 concentration) treatment significantly accelerated the migration of corneal epithelial cells and induced upregulation of the expression of IL-6, EGF, and C-X-C chemokine receptor type 4 mRNAs. Overall, in this study, topical administration of cell-free CM promoted regeneration of the corneal epithelium after induction of chemical burns.

Thymoquinone-Induced Tristetraprolin Inhibits Tumor Growth and Metastasis through Destabilization of MUC4 mRNA.

Tristetraprolin (TTP), a well-characterized AU-rich element (ARE) binding protein, functions as a tumor suppressor gene. The purpose of this study was to investigate whether a bioactive substance derived from a natural medicinal plant affects the induction of TTP and to elucidate its mechanism. We examined the effects of natural bioactive materials including Resveratrol (RSV), thymoquinone (TQ) and curcumin on the expression of TTP in cancer cell. TQ derived from a natural plant Nigella sativa increased the expression levels of TTP mRNA and proteins in a dose-dependent manner in gastric and breast cancer cells. TQ-induced TTP increased the instability of MUC4 mRNA by direct binding of TTP to ARE in the 3'UTR of MUC4 mRNA. The induction of TTP by TQ also reduced the proliferation, migration and invasion of cancer cells. The expression of the epithelial-mesenchymal (EMT)-related genes, which were target genes of TTP, was also decreased by the TQ treatment. In the in vivo experiments using mouse melanoma cells, TQ-induced TTP inhibited metastasis of tumor cells. We have found that TQ-induced TTP might inhibit metastasis by reducing tumor cell migration and invasion through destabilization of MUC4 mRNA, which suggest the MUC4 as a novel target to TTP.

Ciprofloxacin Enhances TRAIL-Induced Apoptosis in Lung Cancer Cells by Upregulating the Expression and Protein Stability of Death Receptors through CHOP Expression.

Ciprofloxacin (CIP) is a potent antimicrobial agent with multiple effects on host cells and tissues. Previous studies have highlighted their proapoptotic effect on human cancer cells. The current study showed that subtoxic doses of CIP effectively sensitized multiple cancer cells to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis. Although TRAIL alone mediated the partial proteolytic processing of procaspase-3 in lung cancer cells, co-treatment with CIP and TRAIL efficiently restored the complete activation of caspases. We found that treatment of lung cancer with CIP significantly upregulated the expression and protein stability of death receptor (DR) 5. These effects were mediated through the regulation of transcription factor CCAT enhancer-binding protein homologous protein (CHOP) since the silencing of these signaling molecules abrogated the effect of CIP. Taken together, these results indicated that the upregulation of death receptor expression and protein stability by CIP contributed to the restoration of TRAIL-sensitivity in lung cancer cells.

Genome-wide evidences of bisphenol a toxicity using Schizosaccharomyces pombe.

To clarify reliable toxic mechanisms of bisphenol A (BPA), an endocrine disrupting chemical, we approached an alternative animal and whole genome analyses with the yeast knockout library (YKO) of Schizosaccharomyces pombe. As results, the 50% growth inhibition concentrations (GI50) of BPA was approximately 600 µM and the YKO-three step screening revealed the top 10 target candidate genes including dbp2, utp18, srs1, tif224, use1, qcr1, etc. The screening results were confirmed in human embryonic stem cell (hES)-derived hepatic cells and HepG2 human liver cancer cells. We found BPA down-regulated UQCRC, the human orthlog of S. pombe- qcr1, as a part of the mitochondrial respiratory chain, in HepG2 cells and hESs during cell differentiation into hepatic cells. Therefore, BPA may induce mitochondrial dysfunction and disruption of differentiation by suppressing UQCRC1.

Correlation of IGF1R expression with ABCG2 and CD44 expressions in human osteosarcoma.

Osteosarcoma is the most common type of malignant bone tumors. Insulin Growth Factor 1 receptor (IGFR1) has been known as a prognostic factor for metastasis of osteosarcoma. ABC subfamily G member2 (ABCG2) is related to resistance to anti-cancer drug, and CD44 has a role in tumor growth and metastasis. The purpose of this study is to investigate the relationship among expression patterns of IGF1R, ABCG2, and CD44 in osteosarcoma. The expression levels of IGF1R, ABCG2, and CD44 proteins were determined in tissue arrays containing osteosarcoma tissues from 59 osteosarcoma patients. The expression pattern of IGF1R was highly correlated with the expression pattern of ABCG2 (r = 0.88) in overall osteosarcoma patients. According to pathological types, the expression pattern of IGF1R showed the higher correlation with ABGC2 (r = 0.90) and CD44 (r = 0.61) in osteoblatic type than in chondroblastic type. According to gender with pathologic type, the correlation between the expression patterns of IGF1R and CD44 was higher in male with osteoblatic type than in female with osteoblatic type. Among different age groups, the 1-10 years age group showed higher correlation in IGF1R versus CD44 (r = 0.90) and ABCG2 versus CD44 (0.80) than in other age groups. These results showed that the expression of IGF1R appears to be highly correlated with the expression of ABCG2 in osteosarcoma and with the expression of CD44 in osteosarcoma patients under age of 10, which suggests that ABCG2 and CD44 can be used as prognostic factors with IGF1R for specific prognosis and efficient treatment of osteosarcoma.

Clinical and genomic landscape of gastric cancer with a mesenchymal phenotype.

Gastric cancer is a heterogeneous cancer, making treatment responses difficult to predict. Here we show that we identify two distinct molecular subtypes, mesenchymal phenotype (MP) and epithelial phenotype (EP), by analyzing genomic and proteomic data. Molecularly, MP subtype tumors show high genomic integrity characterized by low mutation rates and microsatellite stability, whereas EP subtype tumors show low genomic integrity. Clinically, the MP subtype is associated with markedly poor survival and resistance to standard chemotherapy, whereas the EP subtype is associated with better survival rates and sensitivity to chemotherapy. Integrative analysis shows that signaling pathways driving epithelial-to-mesenchymal transition and insulin-like growth factor 1 (IGF1)/IGF1 receptor (IGF1R) pathway are highly activated in MP subtype tumors. Importantly, MP subtype cancer cells are more sensitive to inhibition of IGF1/IGF1R pathway than EP subtype. Detailed characterization of these two subtypes could identify novel therapeutic targets and useful biomarkers for prognosis and therapy response.

Changes in skin reactivity and associated factors in patients sensitized to house dust mites after 1 year of allergen-specific immunotherapy.

BACKGROUND: Allergen-specific immunotherapy (SIT) can significantly improve symptoms and reduce the need for symptomatic medication. OBJECTIVE: The aim of this study was to investigate changes in skin reactivity to house dust mites (HDMs) as an immunologic response and associated factors after 1 year of immunotherapy. METHODS: A total of 80 patients with allergic airway diseases who received subcutaneous SIT with HDMs from 2009 to 2014 were evaluated. The investigated parameters were basic demographic characteristics, skin reactivity and specific IgE for HDM, serum total IgE level, blood eosinophil counts, and medication score. RESULTS: The mean levels of skin reactivity to HDMs, blood eosinophil counts, and medication scores after 1 year were significantly reduced from baseline. In univariate comparison of the changes in skin reactivity to HDMs, age ≤30 years, HDMs only as target of immunotherapy, and high initial skin reactivity (≥2) to HDMs were significantly associated with the reduction in skin test reactivity. In multivariate analysis, high initial skin reactivity and HDMs only as target allergens were significantly associated with changes in skin reactivity to HDMs. In the receiver operating characteristic curve of the initial mean skin reactivity to HDMs for more than 50% reduction, the optimal cutoff value was 2.14. CONCLUSION: This study showed significant reductions in allergen skin reactivity to HDMs after 1 year of immunotherapy in patients sensitized to HDMs. The extent of initial allergen skin reactivity and only HDMs as target allergen were important predictive factors for changes in skin reactivity.

A polymorphic minisatellite region of BORIS regulates gene expression and its rare variants correlate with lung cancer susceptibility.

Aberrant expression of BORIS/CTCFL (Brother of the Regulator of Imprinted Sites/CTCF-like protein) is reported in different malignancies. In this study, we characterized the entire promoter region of BORIS/CTCFL, including the CpG islands, to assess the relationship between BORIS expression and lung cancer. To simplify the construction of luciferase reporter cassettes with various-sized portions of the upstream region, genomic copies of BORIS were isolated using TAR cloning technology. We analyzed three promoter blocks: the GATA/CCAAT box, the CpG islands and the minisatellite region BORIS-MS2. Polymorphic minisatellite sequences were isolated from genomic DNA prepared from the blood of controls and cases. Of the three promoter blocks, the GATA/CCAAT box was determined to be a critical element of the core promoter, while the CpG islands and the BORIS-MS2 minisatellite region were found to act as regulators. Interestingly, the polymorphic minisatellite region BORIS-MS2 was identified as a negative regulator that repressed the expression levels of luciferase reporter cassettes less effectively in cancer cells compared with normal cells. We also examined the association between the size of BORIS-MS2 and lung cancer in a case-control study with 590 controls and 206 lung cancer cases. Rare alleles of BORIS-MS2 were associated with a statistically significantly increased risk of lung cancer (odds ratio, 2.04; 95% confidence interval, 1.02-4.08; and P=0.039). To conclude, our data provide information on the organization of the BORIS promoter region and gene regulation in normal and cancer cells. In addition, we propose that specific alleles of the BORIS-MS2 region could be used to identify the risk for lung cancer.

Inactivation of Hippo Pathway Is Significantly Associated with Poor Prognosis in Hepatocellular Carcinoma.

PURPOSE: The Hippo pathway is a tumor suppressor in the liver. However, the clinical significance of Hippo pathway inactivation in HCC is not clearly defined. We analyzed genomic data from human and mouse tissues to determine clinical relevance of Hippo pathway inactivation in HCC. EXPERIMENTAL DESIGN: We analyzed gene expression data from Mst1/2(-/-) and Sav1(-/-) mice and identified a 610-gene expression signature reflecting Hippo pathway inactivation in the liver [silence of Hippo (SOH) signature]. By integrating gene expression data from mouse models with those from human HCC tissues, we developed a prediction model that could identify HCC patients with an inactivated Hippo pathway and used it to test its significance in HCC patients, via univariate and multivariate Cox analyses. RESULTS: HCC patients (National Cancer Institute cohort, n = 113) with the SOH signature had a significantly poorer prognosis than those without the SOH signature [P < 0.001 for overall survival (OS)]. The significant association of the signature with poor prognosis was further validated in the Korean (n = 100, P = 0.006 for OS) and Fudan University cohorts (n = 242, P = 0.001 for OS). On multivariate analysis, the signature was an independent predictor of recurrence-free survival (HR, 1.6; 95% confidence interval, 1.12-2.28: P = 0.008). We also demonstrated significant concordance between the SOH HCC subtype and the hepatic stem cell HCC subtype that had been identified in a previous study (P < 0.001). CONCLUSIONS: Inactivation of the Hippo pathway in HCC is significantly associated with poor prognosis.

Activation of EZH2 and SUZ12 Regulated by E2F1 Predicts the Disease Progression and Aggressive Characteristics of Bladder Cancer.

PURPOSE: Previous study identified E2F1 as a key mediator of non-muscle-invasive bladder cancer (NMIBC) progression. The aim of this study was to identify the E2F1-related genes associated with poor prognosis and aggressive characteristics of bladder cancer. EXPERIMENTAL DESIGN: Microarray analysis was performed to find E2F1-related genes associated with tumor progression and aggressiveness in the gene expression data from 165 primary patients with bladder cancer. The biologic activity of E2F1-related genes in tumor progression and aggressiveness was confirmed with experimental assays using bladder cancer cells and tumor xenograft assay. RESULTS: The expression of E2F1 was significantly associated with EZH2 and SUZ12. The overexpression of E2F1, EZH2, and SUZ12 enhanced cancer progression including cell colony formation, migration, and invasiveness. Knockdown of these genes reduced motility, blocked invasion, and decreased tumor size in vivo. E2F1 bound the proximal EZH2 and SUZ12 promoter to activate transcription, suggesting that E2F1 and its downstream effectors, EZH2 and SUZ12, could be important mediators for the cancer progression. In addition, we confirmed an association between these genes and aggressive characteristics. Interestingly, the treatment of anticancer drugs to the cells overexpressing E2F1, EZH2, and SUZ12 induced the expression of CD44, KLF4, OCT4, and ABCG2 known as cancer stem cell (CSC)-related genes. CONCLUSIONS: The link between E2F1, EZH2, and/or SUZ12 revealed that E2f1 directly regulates transcription of the EZH2 and SUZ12 genes. The signature of E2F1-EZH2-SUZ12 shows a predictive value for prognosis in bladder tumors and the E2F1-EZH2-SUZ12-driven transcriptional events may regulate the cancer aggressiveness and chemo-resistance, which may provide opportunity for development of new treatment modalities.

Tunicamycin promotes apoptosis in leukemia cells through ROS generation and downregulation of survivin expression.

Tunicamycin (TN), one of the endoplasmic reticulum stress inducers, has been reported to inhibit tumor cell growth and exhibit anticarcinogenic activity. However, the mechanism by which TN initiates apoptosis remains poorly understood. In the present study, we investigated the effect of TN on the apoptotic pathway in U937 cells. We show that TN induces apoptosis in association with caspase-3 activation, generation of reactive oxygen species (ROS), and downregulation of survivin expression. P38 MAPK (mitogen-activated protein kinase) and the generation of ROS signaling pathway play crucial roles in TN-induced apoptosis in U937 cells. We hypothesized that TN-induced activation of p38 MAPK signaling pathway is responsible for cell death. To test this hypothesis, we selectively inhibited MAPK during treatment with TN. Our data demonstrated that inhibitor of p38 (SB), but not ERK (PD) or JNK (SP), partially maintained apoptosis during treatment with TN. Pre-treatment with NAC and GSH markedly prevented cell death, suggesting a role for ROS in this process. Ectopic expression of survivin in U937 cells attenuated TN-induced apoptosis by suppression of caspase-3 cleavage, mitochondrial membrane potential, and cytochrome c release in U937 cells. Taken together, our results show that TN modulates multiple components of the apoptotic response of human leukemia cells and raise the possibility of a novel therapeutic strategy for hematological malignancies.

Genomic predictors for recurrence patterns of hepatocellular carcinoma: model derivation and validation.

BACKGROUND: Typically observed at 2 y after surgical resection, late recurrence is a major challenge in the management of hepatocellular carcinoma (HCC). We aimed to develop a genomic predictor that can identify patients at high risk for late recurrence and assess its clinical implications. METHODS AND FINDINGS: Systematic analysis of gene expression data from human liver undergoing hepatic injury and regeneration revealed a 233-gene signature that was significantly associated with late recurrence of HCC. Using this signature, we developed a prognostic predictor that can identify patients at high risk of late recurrence, and tested and validated the robustness of the predictor in patients (n = 396) who underwent surgery between 1990 and 2011 at four centers (210 recurrences during a median of 3.7 y of follow-up). In multivariate analysis, this signature was the strongest risk factor for late recurrence (hazard ratio, 2.2; 95% confidence interval, 1.3-3.7; p = 0.002). In contrast, our previously developed tumor-derived 65-gene risk score was significantly associated with early recurrence (p = 0.005) but not with late recurrence (p = 0.7). In multivariate analysis, the 65-gene risk score was the strongest risk factor for very early recurrence (<1 y after surgical resection) (hazard ratio, 1.7; 95% confidence interval, 1.1-2.6; p = 0.01). The potential significance of STAT3 activation in late recurrence was predicted by gene network analysis and validated later. We also developed and validated 4- and 20-gene predictors from the full 233-gene predictor. The main limitation of the study is that most of the patients in our study were hepatitis B virus-positive. Further investigations are needed to test our prediction models in patients with different etiologies of HCC, such as hepatitis C virus. CONCLUSIONS: Two independently developed predictors reflected well the differences between early and late recurrence of HCC at the molecular level and provided new biomarkers for risk stratification. Please see later in the article for the Editors' Summary.

Methylene blue-mediated photodynamic therapy enhances apoptosis in lung cancer cells.

Combined treatment with a photosensitizer and iodide laser [photodynamic therapy (PDT)] has improved the outcome of various cancers. In this study, we investigated the effects of using the photosensitizer methylene blue (MB) in PDT in human lung adenocarcinoma cells. We found that MB enhances PDT-induced apoptosis in association with downregulation of anti-apoptotic proteins, reduced mitochondrial membrane potential (MMP), increased phosphorylation of the mitogen-activated protein kinase (MAPK) and the generation of reactive oxygen species (ROS). In MB-PDT-treated A549 cells, we observed PARP cleavage, procaspase-3 activation, downregulation of the anti-apoptotic proteins Bcl-2 and Mcl-1, and the reduction of mitochondrial membrane potential (MMP). Western blot data showed that phosphorylation of p38 was increased in MB-PDT-treated A549 cells, indicating that several signaling molecules participate in the apoptotic cascade. Our data also showed that apoptotic cell death in MB-PDT-treated cells occurred through a series of steps beginning with the photochemical generation of ROS. Demonstrating the role of ROS, pretreatment of A549 cells with the antioxidant N-acetylcysteine (NAC) followed by MB-PDT resulted in increased cell viability and reduced proteolytic cleavage of PARP.

Transcriptional characterization of Wnt pathway during sequential hepatic differentiation of human embryonic stem cells and adipose tissue-derived stem cells.

Human embryonic stem cells (hESs) and adipose-derived stem cells (hADSCs) are able to differentiate into hepatocytes. However, a role of Wnt signaling in hepatic differentiation of stem cells is unclear. This study characterized the transcriptional expression pattern of Wnt signaling genes during the sequential hepatocytes differentiation of hES and hADSC. The sequential hepatocytes differentiation of hES and hADSC was induced by three steps including induction, differentiation and maturation steps with the treatment of cytokines. Hepatocytes differentiation was more efficient in hES than hADSC in terms of the expression of hepatocyte-specific genes and the cellular uptake of ICG. The expression of WNT2B, WNT5A, and WISP1 increased at late hepatic differentiation of hES, but the expression of DKK1 and CCND1 decreased during early hepatic differentiation of hES. During hepatic differentiation of hADSC, the expression of WNT2B and WISP1 decreased, but the expression of WNT5B and DKK1 increased at late hepatic differentiation. These results showed that Wnt signaling appears to be activated in hepatic differentiation of hES, but repressed in hepatic differentiation of hADSC in a time-dependent manner, which suggests the differential regulation of Wnt signaling for hepatic differentiation of hES and hADSC.

Association of MUC6-minisatellite variants with susceptibility to rectal carcinoma.

A secreted MUC6 mucin is reported to be expressed highly in the stomach and gall bladder. In previous our study, the five minisatellites were identified and a significant association between MUC6-MS5 alleles and gastric cancer was reported. Because of aberrant MUC6 expression is often found in gastrointestinal diseases, we evaluated a relationship between MUC6-MS5 and susceptibility to colorectal cancers. Case-control study was performed with 1,103 cancer-free controls and 414 rectal cancer cases. A significant association (OR = 2.70) between short rare MUC6-MS5 alleles (7, 9 repeats) and the occurrence of cancer was observed in rectal cancer [95 % confidence interval (CI), 1.12-6.54; p = 0.022]. Furthermore, a comparison by gender showed the differences in the association ratios between rectal cancer and short rare MUC6-MS5 alleles: male, 3.97 (CI: 1.36-11.5; p = 0.006) versus female 0.91 (CI: 0.18-4.75; p = 0.913). We also examined the association according to lymphovascular invasion (LVI). The frequency of LVI positive rectal cancer was increased in short rare allele cases than in the total rectal cases: 16.2 % versus 42.9 %. Therefore, we suggest that the short rare MUC6-MS5 alleles may be related to cancer development in male and these cancer cases may be related the bad prognosis.

Nuclear factor-kappa B is not involved in titanium dioxide-induced inflammation.

Research over recent years have shown that titanium dioxide (TiO2) nanoparticles (NPs) induce inflammation in various lung, kidney, liver and brain cells. Although the mechanism of inflammation is unclear, existing literature suggests the underlying role of oxidative stress. On the other hand, it has also been shown that nuclear factor-kappa B (NF-kappaB) is activated in response to pro-inflammatory cytokines. In this study we investigated the involvement of NF-kappaB in TiO2-induced inflammation in human lung adenocarcinomic epithelial cells (A549 cells). After 24h of treatment, IL-8 protein release from A549 cells, induced by 10, 50 and 250 microg/ml of P25 TiO2 NPs, were statistically significantly raised, compared to that of the control. This finding corroborates existing literature in that TiO2 NPs induce a dose-dependent increase in the release of IL-8 protein when exposed to A549 cells. However, the binding of NF-kappaB DNA was not affected after 6 h of incubation with P25. Therefore, NF-kappaB DNA binding is not the likely transcription pathway that leads to TiO2-induced inflammation.

Tunicamycin sensitizes human prostate cells to TRAIL-induced apoptosis by upregulation of TRAIL receptors and downregulation of cIAP2.

The addition of tunicamycin to prostate cancer cells enhances cell death mediated by tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). In this study, we investigated whether tunicamycin, an endoplasmic reticulum stress inducer, can potentiate TRAIL-induced apoptosis in human prostate cancer cells. We evaluated the combination of tunicamycin and TRAIL and found synergistic promotion of apoptosis in prostate cancer cells. The combined treatment with tunicamycin and TRAIL significantly induced apoptosis, and stimulated caspase-3, -8 and -9 activity, as well as the cleavage of poly (ADP-ribose) polymerase. We found that tunicamycin promoted TRAIL-induced apoptosis by the upregulation of death receptor (DR)4 and DR5 and the downregulation of cellular inhibitor of apoptosis 2 (cIAP2). In addition, downregulation of cIAP2 expression using small interfering RNA significantly attenuated the apoptosis induced by TRAIL. Taken together, our results demonstrate that the combination of tunicamycin and TRAIL may provide a novel strategy for treating prostate cancer by overcoming critical mechanisms of apoptosis resistance.

Direct and indirect contribution of human embryonic stem cell-derived hepatocyte-like cells to liver repair in mice.

BACKGROUND & AIMS: Many studies of embryonic stem cells have investigated direct cell replacement of damaged tissues, but little is known about how donor cell-derived signals affect host tissue regeneration. We investigated the direct and indirect roles of human embryonic stem cell-derived cells in liver repair in mice. METHODS: To promote the initial differentiation of human embryonic stem cells into mesendoderm, we activated the ß-catenin signaling pathway with lithium; cells were then further differentiated into hepatocyte-like cells. The differentiated cells were purified by indocyanine green staining and laser microdissection and characterized by immunostaining, polymerase chain reaction, biochemical function, electron microscopy, and transplantation analyses. To investigate indirect effects of these cells, secreted proteins (secretomes) were analyzed by a label-free quantitative mass spectrometry. Carbon tetrachloride was used to induce acute liver injury in mice; cells or secreted proteins were administered by intrasplenic or intraperitoneal injection, respectively. RESULTS: The differentiated hepatocyte-like cells had multiple features of normal hepatocytes, engrafted efficiently into mice, and continued to have hepatic features; they promoted proliferation of host hepatocytes and revascularization of injured host liver tissues. Proteomic analysis identified proteins secreted from these cells that might promote host tissue repair. Injection of the secreted proteins into injured livers of mice promoted significant amounts of tissue regeneration without cell grafts. CONCLUSIONS: Hepatocyte-like cells derived from human embryonic stem cells contribute to recovery of injured liver tissues in mice, not only by cell replacement but also by delivering trophic factors that support endogenous liver regeneration.