The major challenge for progressive multiple sclerosis therapy is the promotion of remyelination from inflammation-induced demyelination. A switch from an M1-to an M2-dominant polarization of microglia is critical in these repair processes. In this study, we identified the homeobox gene msh-like homeobox-3 (Msx3) as a new pivotal regulator for microglial polarization. MSX3 was induced during microglia M2 polarization and repressed in M1 cells. The expression of MSX3 in microglia was dynamically regulated during experimental autoimmune encephalomyelitis (EAE), which is an animal model of multiple sclerosis. The overexpression of MSX3 in microglia promoted M2 but impeded M1 polarization. Interrupting MSX3 expression in microglia accelerated inflammation-induced demyelination and neurodegeneration. The conditioned medium from MSX3-transduced microglia promoted oligodendrocyte progenitor survival, differentiation, and neurite outgrowth. The adoptive transfer of MSX3-transduced microglia suppressed EAE and facilitated remyelination within the murine CNS in EAE and the LPC model. Mechanically, chromatin immunoprecipitation assays also indicated that MSX3 directly regulated three key genes associated with microglia M2 polarization, including Pparg, Stat6, and Jak3. Importantly, we found that overexpression of MSX3 in human-derived microglia represents the M2 phenotype and ameliorated EAE after intraventricular injection. Our findings suggest a new homeobox protein-dependent mechanism for driving microglia M2 polarization and identify MSX3 as an attractive therapeutic approach for preventing inflammation-induced demyelination and promoting remyelination.

Metastasis is a major cause of death in patients with breast cancer. In the process of cancer development, epithelial-mesenchymal transition (EMT) is crucial to promoting the invasion and migration of tumor cells. In a previous study, the role of resveratrol in migration and metastasis was investigated in MDA-MB-231 (MDA231) human breast cancer cells and a xenograft-bearing mouse model. Additionally, the related mechanism was explored. In the present study, in vitro Transwell assays showed that resveratrol can inhibit the migration of transforming growth factor (TGF)-β1-induced MDA231 cells in a concentration-dependent manner. An enzyme-linked immunosorbent assay (ELISA) showed that resveratrol can reduce the secretion of matrix metalloproteinase (MMP)-2 and MMP-9. Immunofluorescence was performed to confirm the expression of EMT-related markers. Immunofluorescence assays confirmed that resveratrol changed the expression of the EMT-related markers E-cadherin and vimentin. Western blot analysis demonstrated that resveratrol decreased the expression levels of MMP-2, MMP-9, Fibronectin, α-SMA, P-PI3K, P-AKT, Smad2, Smad3, P-Smad2, P-Smad3, vimentin, Snail1, and Slug, as well as increased the expression levels of E-cadherin in MDA231 cells. In vivo, resveratrol inhibited lung metastasis in a mouse model bearing MDA231 human breast cancer xenografts without marked changes in body weight or liver and kidney function. These results indicate that resveratrol inhibits the migration of MDA231 cells by reversing TGF-β1-induced EMT and inhibits the lung metastasis of MDA231 human breast cancer in a xenograft-bearing mouse model.

Abstract. The aim of the present study was to explore the effect of naringenin on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in a mouse model, as well as the underlying mechanism. The animals were randomly assigned to four groups: PBS-treated healthy control (Control), LPS-induced ALI (LPS), vehicle-treated ALI (LPS + Vehicle), and naringenin-treated ALI (LPS + Nar) group. Naringenin (100 mg/kg) was administered orally for 4 consecutive days, starting 3 days prior to induction of ALI. The survival rates of mice, lung wet/dry weight ratios, lung injury score, protein levels of bronchoalveolar lavage fluid (BALF), lactate dehydrogenase (LDH) activity in the BALF, lung myeloperoxidase (MPO) activity, the number of infiltrated neutrophils and reactive oxygen species (ROS) levels (H 2 O 2 and malondialdehyde) were assessed. In addition, the serum and BALF levels of inflammatory cytokines [tumor necrosis factor-α, interleukin (IL)-1β, IL-6 and macrophage inflammatory protein 2] were determined, along with the total and the phosphorylated protein levels of phosphatidylinositol 3-hydroxy kinase (PI3K) and AKT in lung tissues. The results showed that naringenin pre-treatment significantly increased the survival rate, improved histopathologic changes, alleviated pulmonary edema and lung vascular leak, downregulated the levels of ROS and reduced neutrophil infiltration as well as the levels of inflammatory cytokines in the serum and BALF. Moreover, naringenin pre-treatment reduced the total and the phosphorylated protein levels of PI3K and AKT. The present study suggested that naringenin pre-treatment ameliorated LPS-induced ALI through its anti-oxidative and anti-inflammatory activity and by inhibition of the PI3K/AKT pathway in mice.

The tumor suppressor p53 has a crucial role in cellular response to DNA damage caused by ionizing radiation, but it is still unclear whether p53 can modulate radiation-induced bystander effects (RIBE). In the present work, three different hepatoma cell lines, namely HepG2 (wild p53), PLC/PRF/5 (mutation p53) and Hep3B (p53 null), were irradiated with γ-rays and then co-cultured with normal Chang liver cell (wild p53) in order to elucidate the mechanisms of RIBE. Results showed that the radiosensitivity of HepG2 cells was higher than that of PLC/PRF/5 and Hep3B cells. Only irradiated HepG2 cells, rather than irradiated PLC/PRF/5 or Hep3B cells, could induce bystander effect of micronuclei (MN) formation in the neighboring Chang liver cells. When HepG2 cells were treated with 20 μm pifithrin-α, an inhibitor of p53 function, or 5 μm cyclosporin A (CsA), an inhibitor of cytochrome-c release from mitochondria, the MN induction in bystander Chang liver cells was diminished. In fact, it was found that after irradiation, cytochrome-c was released from mitochondria into the cytoplasm only in HepG2 cells in a p53-dependent manner, but not in PLC/PRF/5 and Hep3B cells. Interestingly, when 50 μg/ml exogenous cytochrome-c was added into cell co-culture medium, RIBE was significantly triggered by irradiated PLC/PRF/5 and Hep3B cells, which previously failed to provoke a bystander effect. In addition, this exogenous cytochrome-c also partly recovered the RIBE induced by irradiated HepG2 cells even with CsA treatment. Our results provide new evidence that the RIBE can be modulated by the p53 status of irradiated hepatoma cells and that a p53-dependent release of cytochrome-c may be involved in the RIBE.

Intrinsic and acquired resistance of cancer to radio-and chemotherapy is one of the major challenges in the treatment of esophageal squamous cell carcinoma (ESCC). Elevated reactive oxygen species (ROS) play an important role in the resistance to cisplatin in ESCCs. Super dismutase [Mn], mitochondrial (SOD-2), an important primary antioxidant enzyme located in mitochondria, could regulate ROS production. Our previous study showed that tumor necrosis factor-α (TNF-α)-mediated SOD-2 through NF-κB was involved in epithelial-mesenchymal transition and migration in A549 cells. Therefore, the present study aimed to identify if TNF-α mediated SOD-2 upregulation is involved in cisplatin resistance in ESCC. It was identified that a higher expression of SOD-2 in human ESCC samples was associated with TNF-α expression and poor overall survival in patients with ESCC, suggesting that SOD-2 may act as an oncogene in ESCC. To further confirm if TNF-α could upregulate SOD-2 to contribute to cell proliferation, the human ESCC cell line Eca-109 was treated with TNF-α in vitro. TNF-α could upregulate SOD-2 and induce cell proliferation in Eca109 cells, while blocking SOD-2 using small interfering RNA (siRNA) inhibited TNF-α-induced cell proliferation. Upregulation of SOD-2 by TNF-α was inhibited by blocking the NF-κB pathway, which suggested that SOD-2 by TNF-α/NF-κB contributes to cell proliferation in Eca109 cells. Furthermore, it was observed that TNF-α could induce cisplatin resistance in Eca109 cells, while transfection with SOD-2 siRNA could significantly increase the chemosensitivity of ESCC to cisplatin. Therefore, the present results suggested that SOD-2 may serve as an oncogene, and the upregulation of SOD-2 by TNF-α/NF-κB may contribute to cisplatin resistance in ESCC.

Abstract. In breast cancer, metastasis is the main reason for patient mortality. In the present study, we used breast cancer MDA-MB-231 cells and a mouse xenograft model to demonstrate the effect of emodin on the migration, invasion and metastasis of human breast cancer MDA-MB-231 cells and the related mechanisms. In vitro, wound healing and Transwell assays showed that emodin dose-dependently inhibited the migration and invasion of MDA-MB-231 cells. Enzyme-linked immunosorbent assay (ELISA) showed that emodin decreased the secretion of MMP-2 and MMP-9. Western blot analysis showed that emodin downregulated the expression levels of MMP-2, MMP-9, uPA and uPAR as well as p38 inhibitor SB203580 and ERK inhibitor PD980559, even though TIMP-1 and TIMP-2 were not obviously changed in the MDA-MB-231 cells. Furthermore, emodin inhibited the activity of p38 and ERK1/2 in the MDA-MB-231 cells. In vivo, emodin inhibited lung metastasis in mice bearing the breast cancer MDA-MB-231 xenografts with no obvious changes in body weight, liver and kidney functions. These results indicated that emodin inhibited the lung metastasis of human breast cancer in a mouse xenograft model, and inhibited the invasion of MDA-MB-231 cells associated with the downregulation of MMP-2, MMP-9, uPA and uPAR expression as well as decreased activity of p38 and ERK.

MHC‐II on alveolar type‐II (AT‐II) cells is associated with immune tolerance in an inflammatory microenvironment. Recently, we found TNF‐α upregulated MHC‐II in AT‐II in vitro. In this study, we explored whether TNF‐α‐mediated inflammation upregulates MHC‐II on AT‐II cells to trigger Treg expansion in inflammation‐driven lung adenocarcinoma (IDLA). Using urethane‐induced mice IDLA model, we found that IDLA cells mainly arise from AT‐II cells, which are the major source of MHC‐II. Blocking urethane‐induced inflammation by TNF‐α neutralization inhibited tumorigenesis and reversed MHC‐II upregulation on tumor cells of AT‐II cellular origin in IDLA. MHC‐II‐dependent AT‐II cells were isolated from IDLA‐induced Treg expansion. In human LA samples, we found high expression of MHC‐II in tumor cells of AT‐II cellular origin, which was correlated with increased Foxp3+ T cells infiltration as well as CXCR‐2 expression. CXCR‐2 and MHC‐II colocalization was observed in inflamed lung tissue and IDLA cells of AT‐II cellular origin. Furthermore, at the pro‐IDLA inflammatory stage, TNF‐α‐neutralization or CXCR‐2 deficiency inhibited the upregulation of MHC‐II on AT‐II cells in inflamed lung tissue. Thus, tumor cells of AT‐II cellular origin contribute to Treg expansion in an MHC‐II‐dependent manner in TNF‐α‐mediated IDLA. At the pro‐tumor inflammatory stage, TNF‐α‐dependent lung inflammation plays an important role in MHC‐II upregulation on AT‐II cells.

Tumor-associated inflammation plays a critical role in facilitating tumor growth, invasion and metastasis. Our previous study showed Aflatoxin G1 (AFG1) could induce lung adenocarcinoma in mice. Chronic lung inflammation associated with superoxide dismutase (SOD)-2 upregulation was found in the lung carcinogenesis. However, it is unclear whether tumor-associated inflammation mediates SOD-2 to contribute to cell invasion in AFG1-induced lung adenocarcinoma. Here, we found increased SOD-2 expression associated with vimentin, α-SMA, Twist1, and MMP upregulation in AFG1-induced lung adenocarcinoma. Tumor-associated inflammatory microenvironment was also elicited, which may be related to SOD-2 upregulation and EMT in cancer cells. To mimic an AFG1-induced tumor-associated inflammatory microenvironment in vitro, we treated A549 cells and human macrophage THP-1 (MΦ-THP-1) cells with AFG1, TNF-α and/or IL-6 respectively. We found AFG1 did not promote SOD-2 expression and EMT in cancer cells, but enhanced TNF-α and SOD-2 expression in MΦ-THP-1 cells. Furthermore, TNF-α could upregulate SOD-2 expression in A549 cells through NF-κB pathway. Blocking of SOD-2 by siRNA partly inhibited TNF-α-mediated E-cadherin and vimentin alteration, and reversed EMT and cell migration in A549 cells. Thus, we suggest that tumor-associated inflammation mediates SOD-2 upregulation through NF-κB pathway, which may contribute to EMT and cell migration in AFG1-induced lung adenocarcinoma.Introduction.