Efficient Suppression of Defects and Charge Trapping in High Density In-Sn-Zn-O Thin Film Transistor Prepared using Microwave-Assisted Sputter.

Amorphous oxide semiconductor-based thin film transistors (TFTs) have been considered as excellent switching elements for driving active-matrix organic light-emitting diodes (AMOLED) owing to their high mobility and process compatibility. However, oxide semiconductors have inherent defects, causing fast transient charge trapping and device instability. For the next-generation displays such as flexible, wearable, or transparent displays, an active semiconductor layer with ultrahigh mobility and high reliability at low deposition temperature is required. Therefore, we introduced high density plasma microwave-assisted (MWA) sputtering method as a promising deposition tool for the formation of high density and high-performance oxide semiconductor films. In this paper, we present the effect of the MWA sputtering method on the defects and fast charge trapping in In-Sn-Zn-O (ITZO) TFTs using various AC device characterization methodologies including fast I-V, pulsed I-V, transient current, low frequency noise, and discharge current analysis. Using these methods, we were able to analyze the charge trapping mechanism and intrinsic electrical characteristics, and extract the subgap density of the states of oxide TFTs quantitatively. In comparison to conventional sputtered ITZO, high density plasma MWA-sputtered ITZO exhibits outstanding electrical performance, negligible charge trapping characteristics and low subgap density of states. High-density plasma MWA sputtering method has high deposition rate even at low working pressure and control the ion bombardment energy, resulting in forming low defect generation in ITZO and presenting high performance ITZO TFT. We expect the proposed high density plasma sputtering method to be applicable to a wide range of oxide semiconductor device applications.

Anti-Proliferative Effect of Naringenin through p38-Dependent Downregulation of Cyclin D1 in Human Colorectal Cancer Cells.

Naringenin (NAR) as one of the flavonoids observed in grapefruit has been reported to exhibit an anti-cancer activity. However, more detailed mechanism by which NAR exerts anti-cancer properties still remains unanswered. Thus, in this study, we have shown that NAR down-regulates the level of cyclin D1 in human colorectal cancer cell lines, HCT116 and SW480. NAR inhibited the cell proliferation in HCT116 and SW480 cells and decreased the level of cyclin D1 protein. Inhibition of proteasomal degradation by MG132 blocked NAR-mediated cyclin D1 downregulation and the half-life of cyclin D1 was decreased in the cells treated with NAR. In addition, NAR increased the phosphorylation of cyclin D1 at threonine-286 and a point mutation of threonine-286 to alanine blocked cyclin D1 downregulation by NAR. p38 inactivation attenuated cyclin D1 downregulation by NAR. From these results, we suggest that NAR-mediated cyclin D1 downregulation may result from proteasomal degradation through p38 activation. The current study provides new mechanistic link between NAR, cyclin D1 downregulation and cell growth in human colorectal cancer cells.

Silymarin induces cyclin D1 proteasomal degradation via its phosphorylation of threonine-286 in human colorectal cancer cells.

Silymarin from milk thistle (Silybum marianum) plant has been reported to show anti-cancer, anti-inflammatory, antioxidant and hepatoprotective effects. For anti-cancer activity, silymarin is known to regulate cell cycle progression through cyclin D1 downregulation. However, the mechanism of silymarin-mediated cyclin D1 downregulation still remains unanswered. The current study was performed to elucidate the molecular mechanism of cyclin D1 downregulation by silymarin in human colorectal cancer cells. The treatment of silymarin suppressed the cell proliferation in HCT116 and SW480 cells and decreased cellular accumulation of exogenously-induced cyclin D1 protein. However, silymarin did not change the level of cyclin D1 mRNA. Inhibition of proteasomal degradation by MG132 attenuated silymarin-mediated cyclin D1 downregulation and the half-life of cyclin D1 was decreased in the cells treated with silymarin. In addition, silymarin increased phosphorylation of cyclin D1 at threonine-286 and a point mutation of threonine-286 to alanine attenuated silymarin-mediated cyclin D1 downregulation. Inhibition of NF-κB by a selective inhibitor, BAY 11-7082 suppressed cyclin D1 phosphorylation and downregulation by silymarin. From these results, we suggest that silymarin-mediated cyclin D1 downregulation may result from proteasomal degradation through its threonine-286 phosphorylation via NF-κB activation. The current study provides new mechanistic link between silymarin, cyclin D1 downregulation and cell growth in human colorectal cancer cells.

The induction of activating transcription factor 3 (ATF3) contributes to anti-cancer activity of Abeliophyllum distichum Nakai in human colorectal cancer cells.

BACKGROUND: Recently, Abeliophyllum distichum Nakai (A. distichum) has been reported to exert the inhibitory effect on angiotensin converting enzyme. However, no specific pharmacological effects from A. distichum have been described. We performed in vitro study to evaluate anti-cancer properties of A. distichum and then elucidate the potential mechanisms. METHODS: Cell viability was measured by MTT assay. ATF3 expression level was evaluated by Western blot or RT-PCR and ATF3 transcriptional activity was determined using a dual-luciferase assay kit after the transfection of ATF3 promoter constructs. In addition, ATF3-dependent apoptosis was evaluated by Western blot after ATF3 knockdown using ATF3 siRNA. RESULTS: Exposure of ethyl acetate fraction from the parts of A. distichum including flower, leaf and branch to human colorectal cancer cells, breast cancer cells and hepatocellular carcinoma reduced the cell viability. The branch extracts from A. distichum (EAFAD-B) increased the expression of activating transcription factor 3 (ATF3) and promoter activity, indicating transcriptional activation of ATF3 gene by EAFAD-B. In addition, our data showed that EAFAD-B-responsible sites might be between -147 and -85 region of the ATF3 promoter. EAFAD-B-induced ATF3 promoter activity was significantly decreased when the CREB site was deleted. However, the deletion of Ftz sites did not affect ATF3 promoter activity by EAFAD-B. We also observed that inhibition of p38MAPK and GSK3ß attenuated EAFAD-B-mediated ATF3 promoter activation. Also, EAFAD-B contributes at least in part to increase of ATF3 accumulation. CONCLUSION: These findings suggest that the anti-cancer activity of EAFAD-B may be a result of ATF3 promoter activation and subsequent increase of ATF3 expression.

The contribution of activating transcription factor 3 to apoptosis of human colorectal cancer cells by protocatechualdehyde, a naturally occurring phenolic compound.

Protocatechualdehyde (PCA) is one of the important compounds found in barley, green cavendish bananas and grapevine leaves. PCA shows anti-cancer activities in breast, leukemia and colorectal cancer cells. Previous study reported that PCA exerts anti-cancer activity through down-regulating cyclin D1 and HDAC2 in human colorectal cancer cells. However, the underlying mechanisms for the expression of activating transcription factor 3 (ATF3) by PCA has not been studied. Thus, we performed in vitro study to investigate if treatment of PCA affects ATF3 expression and ATF3-mediated apoptosis in human colorectal cancer cells. PCA decreased cell viability in a dose-dependent manner in HCT116 and SW480 cells. In addition, PCA reduced cell viability in MCF-7, MDA-MB-231 and HepG-2 cells. Exposure of PCA activated the levels of ATF3 protein and mRNA in HCT116 and SW480 cells. Inhibition of ERK1/2/ by PD98059 and p38 by SB203580 inhibited PCA-induced ATF3 expression and transcriptional activation. ATF3-knockdown inhibited PCA-induced apoptosis and cell viability. In addition, ATF3 overexpression enhanced PCA-mediated cleavage of PARP. These findings suggest that inhibition of cell viability and apoptosis by PCA may be result of ATF3 expression through ERK1/2 and p38-mediated transcriptional activation.

Anti-cancer activity of Ginger (Zingiber officinale) leaf through the expression of activating transcription factor 3 in human colorectal cancer cells.

BACKGROUND: Ginger leaf (GL) has long been used as a vegetable, tea and herbal medicine. However, its pharmacological properties are still poorly understood. Thus, we performed in vitro studies to evaluate anti-cancer properties of ginger leaf and then elucidate the potential mechanisms involved. METHODS: Cell viability was measured by MTT assay. ATF3 expression level was evaluated by Western blot or RT-PCR and ATF3 transcriptional activity was determined using a dual-luciferase assay kit after the transfection of ATF3 promoter constructs. In addition, ATF3-dependent apoptosis was evaluated by Western blot after ATF3 knockdown using ATF3 siRNA. RESULTS: Exposure of GL to human colorectal cancer cells (HCT116, SW480 and LoVo cells) reduced the cell viability and induced apoptosis in a dose-dependent manner. In addition, GL reduced cell viability in MCF-7, MDA-MB-231 and HepG-2 cells. ATF3 knockdown attenuated GL-mediated apoptosis. GL increased activating transcription factor 3 (ATF3) expressions in both protein and mRNA level and activated ATF3 promoter activity, indicating transcriptional activation of ATF3 gene by GL. In addition, our data showed that GL-responsible sites might be between -318 and -85 region of the ATF3 promoter. We also observed that ERK1/2 inhibition by PD98059 attenuated GL-mediated ATF3 expression but not p38 inhibition by SB203580, indicating ERK1/2 pathway implicated in GL-induced ATF3 activation. CONCLUSIONS: These findings suggest that the reduction of cell viability and apoptosis by GL may be a result of ATF3 promoter activation and subsequent increase of ATF3 expression through ERK1/2 activation in human colorectal cancer cells.

Anti-inflammatory and anti-cancer activity of mulberry (Morus alba L.) root bark.

BACKGROUND: Root bark of mulberry (Morus alba L.) has been used in herbal medicine as anti-phlogistic, liver protective, kidney protective, hypotensive, diuretic, anti-cough and analgesic agent. However, the anti-cancer activity and the potential anti-cancer mechanisms of mulberry root bark have not been elucidated. We performed in vitro study to investigate whether mulberry root bark extract (MRBE) shows anti-inflammatory and anti-cancer activity. METHODS: In anti-inflammatory activity, NO was measured using the griess method. iNOS and proteins regulating NF-κB and ERK1/2 signaling were analyzed by Western blot. In anti-cancer activity, cell growth was measured by MTT assay. Cleaved PARP, ATF3 and cyclin D1 were analyzed by Western blot. RESULTS: In anti-inflammatory effect, MRBE blocked NO production via suppressing iNOS over-expression in LPS-stimulated RAW264.7 cells. In addition, MRBE inhibited NF-κB activation through p65 nuclear translocation via blocking IκB-α degradation and ERK1/2 activation via its hyper-phosphorylation. In anti-cancer activity, MRBE deos-dependently induced cell growth arrest and apoptosis in human colorectal cancer cells, SW480. MRBE treatment to SW480 cells activated ATF3 expression and down-regulated cyclin D1 level. We also observed that MRBE-induced ATF3 expression was dependent on ROS and GSK3ß. Moreover, MRBE-induced cyclin D1 down-regulation was mediated from cyclin D1 proteasomal degradation, which was dependent on ROS. CONCLUSIONS: These findings suggest that mulberry root bark exerts anti-inflammatory and anti-cancer activity.

The cancer preventive seed peptide lunasin from rye is bioavailable and bioactive.

Lunasin is a unique 43-amino acid peptide that has been shown to be chemopreventive in mammalian cells and in a skin cancer mouse model against oncogenes and chemical carcinogens. In search for new sources of lunasin and to better understand the role of cereals in cancer prevention, we report here the properties of lunasin from rye. The stability and bioavailability were measured by in vitro digestibility assay using pepsin and pancreatin and feeding rats with lunasin-enriched rye (LER). Inhibition of histone acetyl transferase (HAT) and nuclear localization in mammalian cells were used to measure lunasin bioactivity. Lunasin is present in 15 out of 21 cultivars of rye analyzed. Lunasin present in rye crude protein preparation is stable to pepsin and pancreatin in in vitro digestion. The liver, kidney, and blood of rats fed LER show the presence of lunasin in Western blot. Lunasin extracted from these tissues inhibits the activities of HATs, confirming that the peptide is intact and bioactive. Lunasin purified from rye internalizes in the nuclei of mouse fibroblast cells. We conclude that lunasin in rye is bioavailable and bioactive and that consumption of rye may play an important role of cancer prevention in rye-consuming populations.

Antioxidant activity in essential oils of Cnidium officinale makino and Ligusticum chuanxiong Hort and their inhibitory effects on DNA damage and apoptosis induced by ultraviolet B in mammalian cell.

BACKGROUND: Owing to their high volatile aroma, the dried rhizomes of Cnidium officinale (C. officinale) and Ligusticum chuanxiong (L. chuanxiong) are used as herbal drugs to treat blood pressure depressant, a deficiency disease of antivitamin, inhibition of small intestine sympathetic nerve and as cosmetics for skin care. However, little has been known about the protective effect of their essential oils against ultraviolet B (UVB)-induced DNA damage. METHODS: In this study, we report antioxidant activity of their essential oils using DPPH and ABTS scavenging assay. In addition, the composition of essential oils was measured by GC/MS. We also investigated whether these essential oils could inhibit UVB-induced DNA damage and apoptosis in the mammalian cell using intracellular DNA migration and expression level of phospho-H2A.X. RESULTS: Twenty constituents in the essential oil were identified and they showed good antioxidant properties, in that IC(50) value in DPPH and ABTS showed 6.79 and 7.33microg/ml and 1.58 and 1.58microg/ml in C. officinale and L. chuanxiong. Their treatment inhibited the migration of damaged DNA induced by UV-B; furthermore, they decreased p21 expression and increased cyclin D1 expression as apoptosis-regulatory genes. CONCLUSIONS: These results suggest that essential oils in C. officinale and L. chuanxiong may exert inhibitory effects on DNA damage and apoptosis induced by UVB through their high free radical scavenging ability.

Protective effect of the extracts from Cnidium officinale against oxidative damage induced by hydrogen peroxide via antioxidant effect.

The dried rhizomes of Cnidium officinale are used as herbal drugs in the treatment of pain, inflammation, menstrual disturbance and antivitamin deficiency disease, and also act as a blood pressure depressant. In addition, there are several reports suggesting that they have pharmacological properties to tumor metastasis and angiogenesis, and that they act as an inhibitor of high glucose-induced proliferation of glomerular mesangial cells. However, little has been known about the functional role of the extracts from C. officinale on oxidative DNA damage and apoptosis caused by ROS. In this work, we have investigated the DPPH radical, hydroxyl radical and intracellular ROS scavenging capacity, and Fe(2+) chelating activity of the extracts from C. officinale. In addition, we evaluated whether the extracts are capable of reducing H(2)O(2)-induced DNA and cell damage in the human skin fibroblast cell. These extracts showed a dose-dependent free-radical scavenging capacity and a protective effect on DNA damage and the lipid peroxidation causing the cell damage by ROS. These antioxidant activities and inhibitory effects of the extracts on DNA and cell damage may further explain that C. officinale is useful as a herbal medicine for cancer chemoprevention.

Cancer-preventive peptide lunasin from Solanum nigrum L. inhibits acetylation of core histones H3 and H4 and phosphorylation of retinoblastoma protein (Rb).

Lunasin, a unique 43 amino acid, 4.8 kDa cancer-chemopreventive peptide initially reported in soybean and now found in barley and wheat, has been shown to be cancer-chemopreventive in mammalian cells and in a skin cancer mouse model against oncogenes and chemical carcinogens. To identify bioactive components in traditional herbal medicines and in search for new sources of lunasin, we report here the properties of lunasin from Solanum nigrum L. (SNL), a plant indigenous to northeast Asia. Lunasin was screened in the crude extracts of five varieties of the medicinal plants of Solanaceae origin and seven other major herbal plants. An in vitro digestion stability assay for measuring bioavailability was carried out on SNL crude protein and autoclaved SNL using pepsin and pancreatin. A nonradioactive histone acetyltransferase (HAT) assay and HAT activity colorimetric assay were used to measure the inhibition of core histone acetylation. The inhibitory effect of lunasin on the phosphorylation of retinoblastoma protein (Rb) was determined by immunoblotting against phospho-Rb. Lunasin isolated from autoclaved SNL inhibited core histone H3 and H4 acetylation, the activities of the HATs, and the phosphorylation of the Rb protein. Lunasin in the crude protein and in the autoclaved crude protein was very stable to pepsin and pancreatin in vitro digestion, while the synthetic pure lunasin was digested at 2 min after the reaction. We conclude that lunasin is a bioactive and bioavailable component in SNL and that consumption of SNL may play an important role in cancer prevention.