Chitinase 3-like 1 protein plays a critical role in respiratory syncytial virus-induced airway inflammation.

BACKGROUND: Chitinase 3-like 1 protein (CHI3L1) (YKL-40 in humans and breast regression protein [BRP]-39 in mice) is required for optimal allergen sensitization and Th2 inflammation in various chronic inflammatory diseases including asthma. However, the role of CHI3L1 in airway inflammation induced by respiratory viruses has not been investigated. The aim of this study was to investigate the relationship between CHI3L1 and airway inflammation caused by respiratory syncytial virus (RSV) infection. METHODS: We measured YKL-40 levels in human nasopharyngeal aspirate (NPA) from hospitalized children presenting with acute respiratory symptoms. Wild-type (WT) and BRP-39 knockout (KO) C57BL/6 mice were inoculated with live RSV (A2 strain). Bronchoalveolar lavage fluid and lung tissue samples were obtained on day 7 after inoculation to assess lung inflammation, airway reactivity, and expression of cytokines and BRP-39. RESULTS: In human subjects, YKL-40 and IL-13 levels in NPA were higher in children with RSV infection than in control subjects. Expression of BRP-39 and Th2 cytokines, IL-13 in particular, was increased following RSV infection in mice. Airway inflammation caused by RSV infection was reduced in BRP-39 KO mice as compared to WT mice. Th2 cytokine levels were not increased in the lungs of RSV-infected BRP-39 KO mice. BRP-39 regulated M2 macrophage activation in RSV-infected mice. Additionally, treatment with anti-CHI3L1 antibody attenuated airway inflammation and Th2 cytokine production in RSV-infected WT mice. CONCLUSION: These findings suggest that CHI3L1 could contribute to airway inflammation induced by RSV infection. CHI3L1 could be a potential therapeutic candidate for attenuating Th2-associated immunopathology during RSV infection.

Curcumin Treatment in Combination with Glucose Restriction Inhibits Intracellular Alkalinization and Tumor Growth in Hepatoma Cells.

Dysregulation of cellular energy metabolism is closely linked to cancer development and progression. Calorie or glucose restriction (CR or GR) inhibits energy-dependent pathways, including IGF-1/PI3K/Akt/mTOR, in cancer cells. However, alterations in proton dynamics and reversal of the pH gradient across the cell membrane, which results in intracellular alkalinization and extracellular acidification in cancer tissues, have emerged as important etiopathogenic factors. We measured glucose, lactate, and ATP production after GR, plant-derived CR-mimetic curcumin treatment, and curcumin plus GR in human hepatoma cells. Intracellular pH regulatory effects, in particular, protein-protein interactions within mTOR complex-1 and its structural change, were investigated. Curcumin treatment or GR mildly inhibited Na+/H+ exchanger-1 (NHE1). vATPase, monocarboxylate transporter (MCT)-1, and MCT4 level. Combination treatment with curcumin and GR further enhanced the inhibitory effects on these transporters and proton-extruding enzymes, with intracellular pH reduction. ATP and lactate production decreased according to pH change. Modeling of mTOR protein revealed structural changes upon treatments, and curcumin plus GR decreased binding of Raptor and GßL to mTOR, as well as of Rag A and Rag B to Raptor. Consequently, 4EBP1 phosphorylation was decreased and cell migration and proliferation were inhibited in a pH-dependent manner. Autophagy was increased by curcumin plus GR. In conclusion, curcumin treatment combined with GR may be a useful supportive approach for preventing intracellular alkalinization and cancer progression.

Inhibition of tumour angiogenesis and growth by small hairpin HIF-1α and IL-8 in hepatocellular carcinoma.

BACKGROUND & AIMS: Hypoxia-inducible factor-1α (HIF-1α), a key transcription factor in the cellular response to hypoxia, and interleukin 8 (IL-8), a key mediator of angiogenesis, are important in cancerous tumour growth. In this study, we evaluated the effects of HIF-1α and IL-8 knockdown on angiogenesis and tumour growth in hepatocellular carcinoma (HCC). METHODS: Hepatocellular carcinoma cell lines were infected with adenoviruses expressing small-hairpin RNA (shRNA) specific for HIF-1α or IL-8, cultured under hypoxic conditions (1% O2), and examined for their levels of HIF-1α, IL-8, and angiogenesis factors using immunoblot. The effects of adenovirus-mediated shRNA-induced HIF-1α and IL-8 knockdown on tumour growth and angiogenesis were also investigated in a subcutaneous Hep3B-tumour mouse model. RESULTS: Hypoxia-inducible factor-1α knockdown directly repressed tumour growth, whereas IL-8 knockdown indirectly repressed tumour growth. Combined knockdown of HIF-1α and IL-8 increased survival rates of mice. HIF-1α and IL-8 knockdown also decreased microvessel density and tumour volume in vivo. Similarly, HIF-1α and IL-8 knockdown inhibited the angiogenic effects of HCC cell-conditioned media on tube formation and invasion by endothelial cells in vitro. CONCLUSION: These findings indicate that shRNA-induced HIF-1α and IL-8 knockdown inhibit angiogenesis and tumour growth in HCC. Further development of HIF-1α and IL-8 shRNA technologies could lead to effective therapies for HCC.

Pre-S mutations of hepatitis B virus affect genome replication and expression of surface antigens.

BACKGROUNDS AND AIMS: In chronic hepatitis B virus (HBV) infection, quantitative HBV surface antigen (qHBsAg) is useful for monitoring viral replication and treatment responses. We aimed to determine whether pre-S mutations have any effect on circulating qHBsAg. METHODS: Plasmids expressing 1­8 amino acid deletion in pre-S1 ("pre-S1Δ1-8") and 3-25 amino acid deletion in pre-S2 ("pre-S2Δ3-25") were constructed. At 72 h posttransfection into Huh7 cells, qHBsAg were measured using electrochemiluminescence immunoassay analyzer. To mimic milieus of quasispecies, we co-transfected either pre-S1Δ1-8 or pre-S2Δ3-25 with wild type (WT). RESULTS: Pre-S mutations affected transcription and replication ability of HBV because of altered overlapping polymerase. Compared with WT, extracellular qHBsAg in pre-S1Δ1-8 and pre-S2Δ3-25 were on average 3.87-fold higher and 0.92-fold lower, respectively, whereas intracellular qHBsAg in pre-S1Δ1-8 and pre-S2Δ3-25 were 0.57-fold lower and 1.60-fold higher, respectively. Immunofluorescence staining of cellular HBsAg showed that pre-S1Δ1-8 had less staining and that pre-S2Δ3-25 had denser staining. As ratios of either pre-S1Δ1-8 or pre-S2Δ3-25:WT increased from 0:10 to 10:0 gradually, relative extracellular qHBsAg increased from 1.0 to 3.85 in pre-S1Δ1-8 co-transfection, whereas those decreased from 1.0 to 0.88 in pre-S2Δ3-25 co-transfection. CONCLUSION: Pre-S mutations exhibit different phenotypes of genome replication and HBsAg expression according to their locations. Thus, qHBsAg level for diagnosis and prognostification in chronic HBV infection should be used more cautiously, considering emergences of pre-S deletion mutants.

Zinc inhibits osteoclast differentiation by suppression of Ca2+-Calcineurin-NFATc1 signaling pathway.

BACKGROUND: Zinc, an essential trace element, inhibits osteoclast differentiation in vitro and in vivo. The molecular mechanism for the inhibitory effect of zinc, however, is poorly understood. The purpose of this study was to investigate the effect of zinc and determine its molecular mechanism on receptor activator of NF-κB ligand (RANKL)-induced osteoclastogenesis in mouse bone marrow-derived monocyte cells (BMMs) and RAW264.7 cells. RESULTS: In BMMs, zinc treatment during osteoclast differentiation decreased RANKL-induced osteoclast formation in a dose-dependent manner. We show that zinc suppressed the mRNA levels of nuclear factor of activated T-cells, cytoplasmic 1 (Nfatc1). Zinc also accumulated phospho-Nfatc1 (p-Nfatc1) in the cytosol in a dose-dependent manner and inhibited the translocation of Nfatc1 to the nucleus in RAW264.7 cells. Zinc suppressed the activities of Nfatc1 in the nucleus without changing the activities of NF-κB in RAW264.7 cells. In contrast, calcineurin activity decreased in response to zinc but its protein level was unchanged. RANKL-induced Ca2+ oscillations were inhibited by zinc treatment, but phospho-phospholipase Cγ1 (p-PLCγ1), the upstream signaling molecule of Ca2+ oscillations, was unaffected. Moreover, a constitutively active form of Nfatc1 obviously rescued suppression of osteoclastogenesis by zinc. CONCLUSIONS: Taken together, these results demonstrate for the first time that the inhibitory effect of zinc during osteoclastogesis is caused by suppressing the Ca2+-Calcineurin-NFATc1 signaling pathway. Thus, zinc may be a useful therapeutic candidate for the prevention of bone loss caused by NFATc1 activation in osteoclasts.

Cell-to-cell contact with hepatitis C virus-infected cells reduces functional capacity of natural killer cells.

The distinct feature of hepatitis C virus (HCV) infection is a high incidence of chronicity. The reason for chronic HCV infection has been actively investigated, and impairment of innate and adaptive immune responses against HCV is proposed as a plausible cause. Whereas functional impairment of HCV-specific T cells is well characterized, the role and functional status of natural killer (NK) cells in each phase of HCV infection are still elusive. We therefore investigated whether direct interaction between NK cells and HCV-infected cells modulates NK cell function. HCV-permissive human hepatoma cell lines were infected with cell culture-generated HCV virions and cocultured with primary human NK cells. Cell-to-cell contact between NK cells and HCV-infected cells reduced NK cells' capacity to degranulate and lyse target cells, especially in the CD56(dim) NK cell subset, which is characterized by low-density surface expression of CD56. The decrease in degranulation capacity was correlated with downregulated expression of NK cell-activating receptors, such as NKG2D and NKp30, on NK cells. The ability of NK cells to produce and secrete gamma interferon (IFN-γ) also diminished after exposure to HCV-infected cells. The decline of IFN-γ production was consistent with the reduction of NK cell degranulation. In conclusion, cell-to-cell contact with HCV-infected cells negatively modulated functional capacity of NK cells, and the inhibition of NK cell function was associated with downregulation of NK-activating receptors on NK cell surfaces. These observations suggest that direct cell-to-cell interaction between NK cells and HCV-infected hepatocytes may impair NK cell function in vivo and thereby contribute to the establishment of chronic infection.

Delayed-Onset Anaphylaxis Caused by IgE Response to Influenza Vaccination.

Influenza vaccine-associated anaphylaxis is a very rare allergic reaction to vaccines, but the most concerning and life-threatening adverse reaction. Although the safety of influenza vaccines has been well documented, occasional cases of anaphylaxis in vaccinated patients have been reported. In this study, we analyzed the immunoglobulin E (IgE) response to whole influenza vaccines in a pediatric case of delayed-onset anaphylaxis after influenza vaccination. The patient showed elevated specific IgE levels against whole influenza vaccines, especially with split virion from egg-based manufacturing process. Specific IgE levels to influenza vaccines showed decreased over. We evaluated a causal relationship between influenza vaccine and anaphylaxis event by enzyme-linked immunosorbent assay. Delayed-onset anaphylaxis after influenza vaccination can occur in children without predisposing allergic diseases. In addition, the results suggested that formulation and production system of influenza vaccines could affect the probability of severe allergic reaction to vaccines.

Effects of transarterial chemoembolization on regulatory T cell and its subpopulations in patients with hepatocellular carcinoma.

BACKGROUND: Regulatory T cell (Treg) plays an essential role in regulating anti-tumor immunity. The aim of this study was to investigate the effect of transarterial chemoembolization (TACE) on Treg in hepatocellular carcinoma (HCC) patients. METHOD: The frequency of peripheral blood Tregs in 27 HCC patients who underwent TACE were measured at baseline and 1 month after TACE. The frequency of peripheral blood Tregs at baseline were compared with those in 23 healthy controls. Tregs were further classified into three subpopulations [Treg (I), Treg (II), Treg (III)] based on expression levels or markers and their function. The patients were divided into two groups according to tumor response after TACE; complete response group and incomplete response group. The correlations between the frequency of Treg and clinical factors were analyzed. RESULTS: The frequency of Treg in HCC patients (7.52%) was significantly higher than in healthy controls (4.99%) at baseline. Regarding Treg subpopulations, the frequency of Treg (II) was significantly higher in HCC patients (2.51%) than in healthy controls (0.60%). In comparison of Treg numbers at baseline and post-TACE by tumor response, the change of Treg (III) in complete response group from baseline to post-TACE was significantly decreased (63.8 → 53.2/mm3). Patients with a high post-TACE Treg (III) (3.8 months) exhibited a significantly shorter median time to progression than those with a low post-TACE Treg (III) (11.6 months). In multivariate analyses, hypoalbuminemia (hazard ratio 3.324; 95% CI 1.098-10.063, p = 0.034) and high post-TACE Treg (III) (hazard ratio 3.080; 95% CI 1.091-8.696, p = 0.034) were significant factors for associating with progression. CONCLUSIONS: The frequency of Tregs in HCC patients was significantly higher than in healthy controls. In addition, patients with a high post-TACE Treg (III) exhibited a significantly lower progression-free survival rate than those with a low post-TACE Treg (III).

Evaluation of the role of hexokinase type II in cellular proliferation and apoptosis using human hepatocellular carcinoma cell lines.

UNLABELLED: The (18)F-FDG uptake pattern on PET could be an indicator of the prognosis and aggressiveness of various tumors, including hepatocellular carcinoma (HCC). Hexokinase, especially hexokinase type II (HKII), plays a critical role in (18)F-FDG uptake in rapidly growing tumors. We established a stable cell line overexpressing HKII by the transfection of full DNA of HKII to HCC cells (SNU449) that express low levels of HKII and investigated how (18)F-FDG uptake mechanisms, especially overexpression of HKII, are linked to tumor proliferation mechanisms. METHODS: The HKII gene was stably transfected to SNU449 cells with an expression vector. HKII expression in the cells was verified by reverse-transcriptase polymerase chain reaction, Western blot analysis, adenosine triphosphate (ATP) and lactate production, (18)F-FDG uptake measurement, and confocal microscopy. Cellular proliferation activity and response to the anticancer drug cisplatin were evaluated by cell counting using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. For the evaluation of molecular pathways involved in tumor proliferation, the phosphatidylinositol 3-kinase (PI3K)/Akt pathway was investigated. RESULTS: The stable cell line produced HKII effectively, but expression of other enzymes or transporters for glycolysis, such as glucose-6-phosphatase (G6Pase), HKI and III, and glucose transporter type 1 and 2 (Glut-1 and Glut-2), did not show any changes. (18)F-FDG uptake was significantly increased after transfection. ATP and lactate production was also increased after transfection. Overexpressed HKII was associated with mitochondria on confocal microscopy. Cells with overexpression of HKII, compared with the nontransfected cell line, showed 1.5- to 2-fold higher cell survival and resistance to the anticancer agent cisplatin (2- to 8-fold). In the molecular study, the activated form of Akt was increased after transfection, and PI3K inhibitor dissociated the mitochondrial HKII to the cytoplasm. In addition, the adenosine monophosphate-activated protein kinase (AMPK) pathway is also involved in Akt signaling. CONCLUSION: HKII plays an important role in (18)F-FDG uptake and tumor proliferation by both the PI3K-dependent and the PI3K-independent Akt signal pathways; therefore, the (18)F-FDG uptake pattern on a PET scan can be a surrogate marker of prognosis in HCC.

Characteristics of B-cell-specific growth substance produced by Bacillus licheniformis E1.

A B cell-specific growth substance (BGS) was isolated from the slime layer of Bacillus licheniformis E1. Unlike LPS, the BGS was not affected by polymixin B, an inhibitor of LPS, or by TLR4, and resulted in the growth of B cells. When BALB/c mice were treated with the BGS, the B cell population was found to increase in both the bone marrow and the spleen, with a marked increase after 24 h in the bone marrow and after 48 h in the spleen. When using antibodies to B cell lineage-restricted surface molecules to analyze the B cell population changes resulting from treatment with the BGS, an increase in immature B cells (IgM(+) and AA4.1(+)) and mature B cells (IgM(+) and IgD(+)) was found in the bone marrow 24 h after treatment with the BGS, whereas a decrease in mature B cells and increase in IgG(+) B cells were found in the spleen. When the BGS and OVA antigen were injected into the peritoneal cavity of BALB/c mice, this resulted in a high OVA-specific antibody titer in the sera, similar to that induced by aluminum hydroxide. Therefore, it is anticipated that the mass production of the BGS by B. licheniformis E1 could be used for studies of B cells in immunology, and contribute to the development of a new adjuvant for vaccine manufacture.

Development of a HA1-specific enzyme-linked immunosorbent assay against pandemic influenza virus A H1N1.

PURPOSE: Enzyme-linked immunosorbent assay (ELISA) has been used in the diverse field to evaluate influenza virus infection; for the surveillance, diagnosis, efficacy evaluation, and development of the vaccine. The aim of this study was to establish an ELISA for detecting HA strain-specific antibodies using recombinant pandemic A H1N1 (pH1N1) HA1 (rHA1) protein. MATERIALS AND METHODS: rHA1 was produced in baculovirus system. The clinical performance of the developed ELISA was validated using human serum samples, by comparison with standard methods for detecting a neutralizing antibody; hemagglutination inhibition (HI) assay and microneutralization test (MNT). The ability of the ELISA system to evaluate the efficacy test of an influenza vaccine was explored by measuring antibody levels in the serum of vaccinated mice. RESULTS: Our ELISA could detect anti-rHA1 antibody in influenza-infected patients and vaccinated subjects. Compared to HI assay and MNT as reference methods, our method showed good performance in detection of anti-rHA1 antibody. Detection of the anti-rHA1 antibody in vaccinated mice and its correlation with titers in HI assay was also proved in a mice model. CONCLUSION: An ELISA system using rHA1 of pH1N1 influenza virus was developed, and showed good clinical performance in diagnosis of influenza virus infection and evaluation of the vaccination efficacy in both human and animal models.

Role of reactive oxygen species-mediated mitochondrial dysregulation in 3-bromopyruvate induced cell death in hepatoma cells : ROS-mediated cell death by 3-BrPA.

Hexokinase type II (HK II) is the key enzyme for maintaining increased glycolysis in cancer cells where it is overexpressed. 3-bromopyruvate (3-BrPA), an inhibitor of HK II, induces cell death in cancer cells. To elucidate the molecular mechanism of 3-BrPA-induced cell death, we used the hepatoma cell lines SNU449 (low expression of HKII) and Hep3B (high expression of HKII). 3-BrPA induced ATP depletion-dependent necrosis and apoptosis in both cell lines. 3-BrPA increased intracellular reactive oxygen species (ROS) leading to mitochondrial dysregulation. NAC (N-acetyl-L: -cysteine), an antioxidant, blocked 3-BrPA-induced ROS production, loss of mitochondrial membrane potential and cell death. 3-BrPA-mediated oxidative stress not only activated poly-ADP-ribose (PAR) but also translocated AIF from the mitochondria to the nucleus. Taken together, 3-BrPA induced ATP depletion-dependent necrosis and apoptosis and mitochondrial dysregulation due to ROS production are involved in 3-BrPA-induced cell death in hepatoma cells.

Raf-1 and protein kinase B regulate cell survival through the activation of NF-kappaB in hepatitis B virus X-expressing cells.

We previously demonstrated that activation of NF-kappaB by the hepatitis B virus X (HBx) gene plays an important role in cell survival. In the present study, we explored the upstream mediators of NF-kappaB activation and their correlations with cell survival. XTT assays and colony generation assays revealed that inhibition of NF-kappaB activation indeed increased cell death in HBx-expressing cells. Utilizing inactivating mutants of signal transducers, we showed that dominant negative mutants of stress-activated protein kinase/extracellular signal-regulated kinase (SEK1) or PKCalpha significantly diminished the HBx-mediated NF-kappaB activation. However, neither of these mutants significantly affected the cell survival in colony generation assays. In contrast, inactivating mutants of Raf-1 or PKB (protein kinase B)/Akt abrogated the HBx-mediated NF-kappaB activation and also suppressed the cell survival. Our results suggest that the Raf-1 or PKB-mediated NF-kappaB activation promotes cell survival in HBx-expressing cells.

Combined effects of swim training and ginseng supplementation on exercise performance time, ROS, lymphocyte proliferation, and DNA damage following exhaustive exercise stress.

The purpose of this study was to analyze the combined effects of regular exercise and ginseng supplementation on peritoneal exudate ROS (reactive oxygen species), lymphocyte proliferation by splenocytes, and DNA damage following exhaustive exercise stress. Thirty-six female BALB/c mice were randomly divided into control (UT, n = 12), trained (TR, n = 12), and ginseng supplemented and trained (GT, n = 12) groups. Each group was divided into two equal subgroups where mice were studied at rest (UTre, TRre, and GTre) or immediately after exhaustive exercise stress (UTex, TRex, and GTex). Animals were bred in the animal facility, where they were housed at 22-24 degrees C and relative humidity (RH) 50-60% in a controlled environment with a 12-hour photoperiod, and provided food and water ad libitum. The trained mice underwent 10 weeks of endurance swim training (5 times/week) in water at 27-30 degrees C for 60 minutes. The analytical items examined were weight, proliferative activity, the production of ROS from peritoneal exudate cells, and DNA damage following exhaustive exercise stress (2 h exercise stress). Significant level was set at p < 0.05. The results obtained showed that the trained group had a significantly lower mean body weight than the untrained group (p < 0.05). However, there was no significant difference between UT and GT. Swim training increased swim survival time in TRex and GTex, and TRex showed the highest swim survival time. With regard to mitogenic activities of splenocytes in response to exhaustive exercise stress, all groups showed much lower lymphocyte proliferative activity when stimulated with media (Med), concanavalin A (ConA), or lipopolysaccharide (LPS) after exhaustive exercise stress. However, GTex had a higher proliferative activity than the other groups. Trained and ginseng-supplemented groups showed lower peritoneal ROS responses and lymphocyte DNA damage levels after exhaustive exercise. These findings suggest that the combined effect of swim training and ginseng supplementation sustain lymphocyte function in the presence of reduced ROS production and DNA damage following acute exercise stress.

Hepatitis C virus impairs natural killer cell activity via viral serine protease NS3.

Hepatitis C virus (HCV) infection is characterized by a high frequency of chronic cases owing to the impairment of innate and adaptive immune responses. The modulation of natural killer (NK) cell functions by HCV leads to an impaired innate immune response. However, the underling mechanisms and roles of HCV proteins in this immune evasion are controversial, especially in the early phase of HCV infection. To investigate the role of HCV nonstructural proteins especially NS3 in the impairment of NK functions, NK cells were isolated from the PBMCs by negative selection. To assess the direct cytotoxicity and IFN-γ production capability of NK cells, co-cultured with uninfected, HCV-infected, HCV-NS3 DNA-transfected Huh-7.5, or HCV-NS replicon cells. To determine the effect of an NS3 serine protease inhibitor, HCV-infected Huh-7.5 cells were treated with BILN-2061. Then, NK cells were harvested and further co-cultured with K-562 target cells. NK cell functions were analyzed by flow cytometry and enzyme-linked immunosorbent assay. When co-cultured with HCV-infected Huh-7.5 cells, the natural cytotoxicity and IFN-γ production capability of NK cells were significantly reduced. NK cell functions were inhibited to similar levels upon co-culture with HCV-NS replicon cells, NS3-transfected cells, and HCV-infected Huh-7.5 cells. These reductions were restored by BILN-2061-treatment. Furthermore, BILN-2061-treatment significantly increased degranulation against K-562 target cells and IFN-γ productivity in NK cells. Consistent with these findings, the expression levels of activating NK cell receptors, such as NKp46 and NKp30, were also increased. In HCV-infected cells, the serine protease NS3 may play a role in the abrogation of NK cell functions in the early phase of infection through downregulation of NKp46 and NKp30 receptors on NK cells. Together, these results suggest that NS3 represents a novel drug target for the treatment of HCV infections.

Role of LOXL2 in the epithelial-mesenchymal transition and colorectal cancer metastasis.

Colorectal cancer (CRC) is one of the most dangerous types of malignant tumors, and cancer metastasis is a major factor in the failure of CRC therapy. Recently, LOXL2 (lysyl oxidase-like 2) has been shown to represent a regulator of epithelial-mesenchymal transition (EMT) in different cancer types. However, LOXL2 has not been reported to be involved in CRC metastasis. In this study, we demonstrated that LOXL2 expression is strongly correlated with the rate of CRC metastasis, it participates in the regulation of EMT-related molecule expression in CRC cells in vitro, and it is involved in migratory potential alterations. Additionally, tissue microarray analysis of CRC patients showed an increase in the probability of developing CRC distant metastasis and a decrease in the survival rate of patients with high LOXL2 expression. The results obtained in this study indicate that LOXL2 is involved in the development and progression of CRC metastasis, and therefore, its expression levels may represent a useful prognostic marker.

Cellular inhibitor of apoptosis protein 2 promotes the epithelial-mesenchymal transition in triple-negative breast cancer cells through activation of the AKT signaling pathway.

Triple-negative breast cancer (TNBC) represents approximately 10-17% of all breast cancers, and patients with TNBC show a poorer short-term prognosis than patients with other types of breast cancer. TNBCs also have a higher tendency for early distant metastasis and cancer recurrence due to induction of the epithelial-mesenchymal transition (EMT). Several recent reports have suggested that inhibitor of apoptosis (IAP) proteins function as regulators of the EMT. However, the roles of these proteins in TNBC are not clear. Accordingly, we investigated the roles of cIAP2 in TNBC. Among eight IAP genes, only cIAP2 was upregulated in TNBC cells compared with that in other breast cancer subtypes. Analysis of TMAs revealed that expression of cIAP2 was upregulated in TNBCs. In vitro studies showed that cIAP2 was highly expressed in TNBC cells compared with that in other types of breast cancer cells. Furthermore, silencing of cIAP2 in TNBC cells induced mesenchymal-epithelial transition (MET)-like processes and subsequently suppressed the migratory ability and invasion capacity of the cells by regulation of Snail through the AKT signaling pathway. In contrast, ectopic expression of cIAP2 in luminal-type breast cancer cells induced activation of the AKT signaling pathway. These results collectively indicated that cIAP2 regulated the EMT in TNBC via activation of the AKT signaling pathway, contributing to metastasis in TNBC. Our study proposes a novel mechanism through which cIAP2 regulates the EMT involving AKT signaling in TNBC cells. We suggest that cIAP2 may be an attractive candidate molecule for the development of targeted therapeutics in the future.

Troglitazone Enhances the Apoptotic Response of DLD-1 Colon Cancer Cells to Photodynamic Therapy.

PURPOSE: The aim of this study was to investigate whether the peroxisomal proliferator-activated receptor gamma (PPARγ) ligand troglitazone in combination with photodynamic therapy (PDT) enhances the apoptotic response of DLD-1 colon cancer cells. MATERIALS AND METHODS: The effects of troglitazone, PDT, and troglitazone in combination with PDT on cell viability and apoptosis were assessed in DLD-1 cells. Cell viability and proliferation were evaluated using the tetrazolium-based MTT assay, and apoptosis was evaluated via cell staining with propidium iodide (PI) and annexin V-FITC. The levels of pro-caspase-3 were measured via Western blot analyses. RESULTS: Treatment of troglitazone and PDT induced the growth retardation and cell death of DLD-1 cells in a dose-dependent manner, respectively. The combination treatment significantly suppressed cell growth and increased the apoptotic response of DLD-1 and resulted in apoptosis rather than necrosis, as shown by PI/annexin V staining and degradation of procaspase-3. CONCLUSION: These results document the anti-proliferative and apoptotic activities of PDT in combination with the PPARγ ligand troglitazone and provide a strong rationale for testing the therapeutic potential of combination treatment in colon cancer.

Regulation of HK2 expression through alterations in CpG methylation of the HK2 promoter during progression of hepatocellular carcinoma.

Hexokinase 2 (HK2) is a rate-determining enzyme in aerobic glycolysis, a process upregulated in tumor cells. HK2 expression is controlled by various transcription factors and epigenetic alterations and is heterogeneous in hepatocellular carcinomas (HCCs), though the cause of this heterogeneity is not known. DNA methylation in the HK2 promoter CpG island (HK2-CGI) and its surrounding regions (shore and shelf) has not previously been evaluated, but may provide clues about the regulation of HK2 expression. Here, we compared HK2 promoter methylation in HCCs and adjacent non-cancerous liver tissues using a HumanMethylation450 BeadChip array. We found that, while the HK2-CGI N-shore was hypomethylated, thereby enhancing HK2 expression, the HK2-CGI was itself hypermethylated in some HCCs. This hypermethylation suppressed HK2 expression by inhibiting interactions between HIF-1α and a hypoxia response element (HRE) located at -234/-230. HCCs that were HK2negative and had distinct promoter CGI methylation were denoted as having a HK2-CGI methylation phenotype (HK2-CIMP), which was associated with poor clinical outcome. These findings indicate that HK2-CGI N-shore hypomethylation and HK2-CGI hypermethylation affect HK2 expression by influencing the interaction between HIF 1α and HRE. HK2-CGI hypermethylation induces HK2-CIMP and could represent a prognostic biomarker for HCC.

Synergic chemoprevention with dietary carbohydrate restriction and supplementation of AMPK-activating phytochemicals: the role of SIRT1.

Calorie restriction or a low-carbohydrate diet (LCD) can increase life span in normal cells while inhibiting carcinogenesis. Various phytochemicals also have calorie restriction-mimetic anticancer properties. We investigated whether an isocaloric carbohydrate-restriction diet and AMP-activated protein kinase (AMPK)-activating phytochemicals induce synergic tumor suppression. We used a mixture of AMPK-activating phytochemical extracts including curcumin, quercetin, catechins, and resveratrol. Survival analysis was carried out in a B16F10 melanoma model fed a control diet (62.14% kcal carbohydrate, 24.65% kcal protein and 13.2% kcal fat), a control diet with multiple phytochemicals (MP), LCD (16.5, 55.2, and 28.3% kcal, respectively), LCD with multiple phytochemicals (LCDmp), a moderate-carbohydrate diet (MCD, 31.9, 62.4, and 5.7% kcal, respectively), or MCD with phytochemicals (MCDmp). Compared with the control group, MP, LCD, or MCD intervention did not produce survival benefit, but LCDmp (22.80±1.58 vs. 28.00±1.64 days, P=0.040) and MCDmp (23.80±1.08 vs. 30.13±2.29 days, P=0.008) increased the median survival time significantly. Suppression of the IGF-1R/PI3K/Akt/mTOR signaling, activation of the AMPK/SIRT1/LKB1pathway, and NF-κB suppression were the critical tumor-suppression mechanisms. In addition, SIRT1 suppressed proliferation of the B16F10 and A375SM cells under a low-glucose condition. Alterations in histone methylation within Pten and FoxO3a were observed after the MCDmp intervention. In the transgenic liver cancer model developed by hydrodynamic transfection of the HrasG12V and shp53, MCDmp and LCDmp interventions induced significant cancer-prevention effects. Microarray analysis showed that PPARα increased with decreased IL-6 and NF-κB within the hepatocytes after an MCDmp intervention. In conclusion, an isocaloric carbohydrate-restriction diet and natural AMPK-activating agents induce synergistic anticancer effects. SIRT1 acts as a tumor suppressor under a low-glucose condition.