Anti-tumorigenic Properties Research Articles

Cucurbitacin E, An Experimental Lead Triterpenoid with Anticancer, Immunomodulatory and Novel Effects Against Degenerative Diseases. A Mini-Review.

A growing number of studies have revealed that natural molecules own interesting antioxidant and anti-apoptotic properties in cell culture as well as in animal models of human diseases such as cancer, inflammatory and neurodegenerative diseases. During the past sixty years, several cucurbitacins have been isolated from a number of cucurbitaceous species, amongst others. Cucurbitacins are triterpenoid compounds originally identify as the bitter components of the Cucurbit family that demonstrated several pro-survival activities in various model of cellular decay. Specifically, Cucurbitacin E (CuE), an oxygenated tetracyclic triterpenoid, has been investigated in a wider array of bioactivities, mainly immunomodulatory. Recently, CuE has been reported to possess anti-inflammatory and anti-tumorigenic properties mediated by its action on the cellular cytoskeleton, on mitotic pathways as well as on cellular autophagy. Few studies also pinpoint the role of CuE in the nervous system as cytostatic for gliomas and neuroprotective in a model of Parkinson's diseases. This review deals with the use of CuE in various experimental models as one of the most promising therapeutic natural molecules against cancer proliferation, as an immunomudulator and for the prevention of neurodegeneration.

TCF4 Is a Molecular Target of Resveratrol in the Prevention of Colorectal Cancer.

The Wnt/β-catenin pathway plays an essential role in the tumorigenesis of colorectal cancer. T-cell factor-4 (TCF4) is a member of the TCF/LEF (lymphoid enhancer factor) family of transcription factors, and dysregulation of β-catenin is decisive for the initiation and progression of colorectal cancer. However, the role of TCF4 in the transcriptional regulation of its target gene remained poorly understood. Resveratrol is a dietary phytoalexin and present in many plants, including grape skin, nuts and fruits. Although resveratrol has been widely implicated in anti-tumorigenic and pro-apoptotic properties in several cancer models, the underlying cellular mechanisms are only partially understood. The current study was performed to elucidate the molecular mechanism of the anti-cancer activity of resveratrol in human colorectal cancer cells. The treatment of resveratrol and other phytochemicals decreased the expression of TCF4. Resveratrol decreases cellular accumulation of exogenously-introduced TCF4 protein, but did not change the TCF4 transcription. The inhibition of proteasomal degradation using MG132 (carbobenzoxy-Leu-Leu-leucinal) and lactacystin ameliorates resveratrol-stimulated down-regulation of TCF4. The half-life of TCF4 was decreased in the cells exposed to resveratrol. Resveratrol increased phosphorylation of TCF4 at serine/threonine residues through ERK (extracellular signal-regulated kinases) and p38-dependent pathways. The TCF4 knockdown decreased TCF/β-catenin-mediated transcriptional activity and sensitized resveratrol-induced apoptosis. The current study provides a new mechanistic link between resveratrol and TCF4 down-regulation and significant benefits for further preclinical and clinical practice.

Novel Evidence for Curcumin and Boswellic Acid-Induced Chemoprevention through Regulation of miR-34a and miR-27a in Colorectal Cancer.

Colorectal cancer is one of the most common causes of cancer-associated mortality worldwide, but it is truly a preventable disease. Both curcumin and boswellic acids are well-established dietary botanicals with potent antitumorigenic properties that have been shown to modulate multiple oncogenic pathways. Recent data suggest that the chemopreventive effects of these botanicals may, in part, be mediated through regulation of key cancer-related microRNAs (miRNA) and their downstream gene targets. Here, we investigated the antitumorigenic effects of curcumin and 3 acetyl-11-keto-β-boswellic acid (AKBA) on modulation of specific cancer-related miRNAs in colorectal cancer cells and validated their protective effects in vivo using a xenograft mouse model. Both curcumin and AKBA inhibited cellular proliferation, induced apoptosis and cell-cycle arrest in colorectal cancer cell lines, and these effects were significantly enhanced with combined treatment. Gene-expression arrays revealed that curcumin and AKBA regulated distinct cancer signaling pathways, including key cell-cycle regulatory genes. Combined bioinformatics and in silico analysis identified apoptosis, proliferation, and cell-cycle regulatory signaling pathways as key modulators of curcumin and AKBA-induced anticancer effects. We discovered that curcumin and AKBA induced upregulation of tumor-suppressive miR-34a and downregulation of miR-27a in colorectal cancer cells. Furthermore, we demonstrated in a mouse xenograft model that both curcumin and AKBA treatments suppressed tumor growth, which corresponded with alterations in the expression of miR-34a and miR-27a, consistent with our in vitro findings. Herein, we provide novel mechanistic evidence for the chemopreventive effects of curcumin and AKBA through regulation of specific miRNAs in colorectal cancer.

Phytochemical regulation of the tumor suppressive microRNA, miR-34a, by p53-dependent and independent responses in human breast cancer cells.

The tumor suppressive microRNA miR-34a is transcriptionally regulated by p53 and shown to inhibit breast cancer cell proliferation as well as being a marker of increased disease free survival. Indole-3-carbinol (I3C) derived from cruciferous vegetables, artemisinin, extracted from the sweet wormwood plant, and artesunate, a semi-synthetic derivative of artemisinin, are phytochemicals with anti-tumorigenic properties however, little is known about the role of microRNAs in their mechanism of action. Human breast cancer cells expressing wild-type (MCF-7) or mutant p53 (T47D) were treated with a concentration range and time course of each phytochemical under conditions of cell cycle arrest as detected by flow cytometry to examine the potential connection between miR-34a expression and their anti-proliferative responses. Real-time PCR and western blot analysis of extracted RNA and total protein revealed artemsinin and artesunate increased miR-34a expression in a dose-dependent manner correlating with down-regulation of the miR-34a target gene, CDK4. I3C stimulation of miR-34a expression required functional p53, whereas, both artemisinin and artesunate up-regulated miR-34a expression regardless of p53 mutational status or in the presence of dominant negative p53. Phytochemical treatments inhibited the luciferase activity of a construct containing the wild-type 3'UTR of CDK4, but not those with a mutated miR-34a binding site, whereas, transfection of miR-34a inhibitors ablated the phytochemical mediated down-regulation of CDK4 and induction of cell cycle arrest. Our results suggest that miR-34a is an essential component of the anti-proliferative activities of I3C, artemisinin, and artesunate and demonstrate that both wild-type p53 dependent and independent pathways are responsible for miR-34a induction.

Curcumin mediates chemosensitization to 5-fluorouracil through miRNA-induced suppression of epithelial-to-mesenchymal transition in chemoresistant colorectal cancer.

Resistance to cytotoxic chemotherapy is a major cause of mortality in colorectal cancer (CRC) patients. Chemoresistance has been linked primarily to a subset of cancer cells undergoing epithelial-mesenchymal transition (EMT). Curcumin, a botanical with antitumorigenic properties, has been shown to enhance sensitivity of cancer cells to chemotherapeutic drugs, but the molecular mechanisms underlying this phenomenon remain unclear. Effects of curcumin and 5-fluorouracil (5FU) individually, and in combination, were examined in parental and 5FU resistant (5FUR) cell lines. We performed a series of growth proliferation and apoptosis assays in 2D and 3D cell cultures. Furthermore, we identified and analyzed the expression pattern of a subset of putative EMT-suppressive microRNAs (miRNAs) and their downstream target genes regulated by curcumin. Chemosensitizing effects of curcumin were validated in a xenograft mouse model. Combined treatment with curcumin and 5FU enhanced cellular apoptosis and inhibited proliferation in both parental and 5FUR cells, whereas 5FU alone was ineffective in 5FUR cells. A group of EMT-suppressive miRNAs were upregulated by curcumin treatment in 5FUR cells. Curcumin suppressed EMT in 5FUR cells by downregulating BMI1, SUZ12 and EZH2 transcripts, key mediators of cancer stemness-related polycomb repressive complex subunits. Using a xenograft and mathematical models, we further demonstrated that curcumin sensitized 5FU to suppress tumor growth. We provide novel mechanistic evidence for curcumin-mediated sensitization to 5FU-related chemoresistance through suppression of EMT in 5FUR cells via upregulation of EMT-suppressive miRNAs. This study highlights the potential therapeutic usefulness of curcumin as an adjunct in patients with chemoresistant advanced CRC.

Antimelanogenic effect of ginsenoside Rg3 through extracellular signal-regulated kinase-mediated inhibition of microphthalmia-associated transcription factor

BackgroundPanax ginseng has been used to prolong longevity and is believed to be useful for improving skin complexion. Ginsenosides are the most active components isolated from ginseng, and ginsenoside Rg3 (G-Rg3) in particular has been demonstrated to possess antioxidative, antitumorigenic, and anti-inflammatory properties. The aim of this study was to examine the ability of G-Rg3 to inhibit melanogenesis. MethodsThe effects of G-Rg3 on melanin contents and the protein levels of tyrosinase, microphthalmia-associated transcription factor (MITF), and tyrosinase-related protein 1 (TRP1) were evaluated. Melanogenesis-regulating signaling molecules such as Akt and extracellular signal-regulated kinase (ERK) were also examined to explore G-Rg3-induced antimelanogenic mechanisms. ResultsG-Rg3 was found to significantly inhibit the synthesis of melanin in normal human epidermal melanocytes and B16F10 cells in a dose-dependent manner. The activity of cellular tyrosinase and the expression of MITF, tyrosinase, and TRP1 were all reduced, whereas ERK was strongly activated. PD98059 (a specific inhibitor of ERK) attenuated the G-Rg3-induced inhibition of melanin synthesis and tyrosinase activity. ConclusionTaken together, these results showed that G-Rg3 induces the activation of ERK, which accounts for its antimelanogenic effects. G-Rg3 may be a promising safe skin-whitening agent, adding to the long list of uses of P. ginseng for the enhancement of skin beauty.

Curcumin ameliorates high glucose-induced neural tube defects by suppressing cellular stress and apoptosis

Curcumin is a naturally occurring polyphenol present in the roots of the Curcuma longa plant (turmeric), which possesses antioxidant, antitumorigenic, and antiinflammatory properties. Here, we test whether curcumin treatment reduces high glucose-induced neural tube defects (NTDs), and if this occurs via blocking cellular stress and caspase activation. Embryonic day 8.5 mouse embryos were collected for use in whole-embryo culture under normal (100 mg/dL) or high (300 mg/dL) glucose conditions, with or without curcumin treatment. After 24 hours in culture, protein levels of oxidative stress makers, nitrosative stress makers, endoplasmic reticulum (ER) stress makers, cleaved caspase 3 and 8, and the level of lipid peroxides were determined in the embryos. After 36 hours in culture, embryos were examined for evidence of NTD formation. Although 10 μmol/L of curcumin did not significantly reduce the rate of NTDs caused by high glucose, 20 μmol/L of curcumin significantly ameliorated high glucose-induced NTD formation. Curcumin suppressed oxidative stress in embryos cultured under high glucose conditions. Treatment reduced the levels of the lipid peroxidation marker, 4-hydroxynonenal, nitrotyrosine-modified protein, and lipid peroxides. Curcumin also blocked ER stress by inhibiting phosphorylated protein kinase RNA-like ER kinase, phosphorylated inositol-requiring protein-1α (p-IRE1α), phosphorylated eukaryotic initiation factor 2α (p-eIF2α), C/EBP-homologous protein, binding immunoglobulin protein, and x-box binding protein 1 messenger RNA splicing. Additionally, curcumin abolished caspase 3 and caspase 8 cleavage in embryos cultured under high glucose conditions. Curcumin reduces high glucose-induced NTD formation by blocking cellular stress and caspase activation, suggesting that curcumin supplements could reduce the negative effects of diabetes on the embryo. Further investigation will be needed to determine if the experimental findings can translate into clinical settings.

The Flavonoid Apigenin Ameliorates Cisplatin-Induced Nephrotoxicity through Reduction of p53 Activation and Promotion of PI3K/Akt Pathway in Human Renal Proximal Tubular Epithelial Cells.

Apigenin is a member of the flavone subclass of flavonoids present in fruits and vegetables. Apigenin has long been considered to have various biological activities, such as antioxidant, anti-inflammatory, and antitumorigenic properties, in various cell types. Cisplatin was known to exhibit cytotoxic effect to renal cells by inducing apoptosis through activation of p53. The present study investigated the antiapoptotic effects of apigenin on the cisplatin-treated human renal proximal tubular epithelial (HK-2) cells. HK-2 cells were pretreated with apigenin (5, 10, 20 μM) for 1 h and then treated with 40 μM cisplatin for various times. Apigenin inhibited the cisplatin-induced apoptosis of HK-2 cells. Interestingly, apigenin itself exerted cytostatic activity because of its ability to induce cell cycle arrest. Apigenin inhibited caspase-3 activity and PARP cleavage in cisplatin-treated cells. Apigenin reduced cisplatin-induced phosphorylation and expression of p53, with no significant influence on production of ROS that is known to induce p53 activation. Furthermore, apigenin promoted cisplatin-induced Akt phosphorylation, suggesting that enhanced Akt activation may be involved in cytoprotection. Taken together, these results suggest that apigenin ameliorates cisplatin-induced apoptosis through reduction of p53 activation and promotion of PI3K/Akt pathway in HK-2 cells.

Protective Effect of Piper aduncum Capsule on DMBA-induced Breast Cancer in Rats.

The possible protective effect of Piper aduncum capsule on DMBA (dimethylbenz[α]anthracene)-induced breast cancer in rats was assessed by monitoring the tumor and lung metastases incidence and recording hematological and biochemical parameters and frequency of micronuclei. Mammary carcinogenesis was induced in 36 female Holtzman rats by providing a single subcutaneous injection of DMBA. Oral administration of P. aduncum capsule lowered adenocarcinoma and lymph node metastases incidence. Pulmonary metastasis was significantly lowered (P < 0.05). Hematological indicators showed that the triglyceride level was significantly lowered (P < 0.01) and high-density lipoprotein (HDL) level was significantly increased (P < 0.01). Also, P. aduncum capsule significantly lowered the C reactive protein (CRP) level (P < 0.01) and malondialdehyde level (P < 0.05). There was a significant decrease in the frequency of DMBA-induced micronucleated polychromatic erythrocyte (P < 0.01). Considering the antitumorigenic, hypolipidemic, anti-inflammatory, antioxidant, and antigenotoxic properties of P. aduncum capsule, we conclude that it has a protective effect on DMBA-induced breast cancer in rats.

Phosphorylation of Merkel Cell Polyomavirus Large Tumor Antigen at Serine 816 by ATM Kinase Induces Apoptosis in Host Cells

Merkel cell carcinoma is a highly aggressive form of skin cancer. Merkel cell polyomavirus (MCV) infection and DNA integration into the host genome correlate with 80% of all Merkel cell carcinoma cases. Integration of the MCV genome frequently results in mutations in the large tumor antigen (LT), leading to expression of a truncated LT that retains pRB binding but with a deletion of the C-terminal domain. Studies from our laboratory and others have shown that the MCV LT C-terminal helicase domain contains growth-inhibiting properties. Additionally, we have shown that host DNA damage response factors are recruited to viral replication centers. In this study, we identified a novel MCV LT phosphorylation site at Ser-816 in the C-terminal domain. We demonstrate that activation of the ATM pathway stimulated MCV LT phosphorylation at Ser-816, whereas inhibition of ATM kinase activity prevented LT phosphorylation at this site. In vitro phosphorylation experiments confirmed that ATM kinase is responsible for phosphorylating MCV LT at Ser-816. Finally, we show that ATM kinase-mediated MCV LT Ser-816 phosphorylation may contribute to the anti-tumorigenic properties of the MCV LT C-terminal domain.

Liver injury attenuation by curcumin in a rat NASH model: an Nrf2 activation-mediated effect?

Nuclear factor-erythroid 2-related factor-2 (Nrf2) acts as a defense system in the development of nonalcoholic steatohepatitis (NASH). Curcumin is a phenolic compound with lipid regulatory, anti-oxidative, anti-inflammatory and anti-tumorigenic properties that is beneficial in defending against NASH and was recently proved to be an Nrf2 activator. The aim of this study was to evaluate whether Nrf2 activation could be involved in NASH mitigation by curcumin. Hepatic, metabolic, and inflammatory parameters, along with hepatic Nrf2 protein expression were explored in adult Sprague-Dawley rats developing high-fat-diet-induced NASH and submitted to curcumin gavage for 6 weeks. Curcumin administration led to lower degrees of hepatic steatosis and inflammation; lower levels of serum aminotransferases, lipids, and homeostasis model assessment of insulin resistance; and lower serum and hepatic contents of tumor necrosis factor-α (TNF-α), interleukin-6, and malondialdehyde. In contrast, higher hepatic contents of glutathione, heme oxygenase-1 and superoxide dismutase were observed in rats with curcumin. Moreover, Nrf2 expression in liver cell nuclei was significantly higher in rats with curcumin. Curcumin can prevent and ameliorate NASH via lipid reduction, improve insulin resistance, improve anti-inflammatory, and have antioxidant effects, possibly related to its activation of Nrf2.

CS-38 * BAI1 IS A NEW TUMOR SUPPRESSOR IN MEDULLOBLASTOMA

Brain-specific Angiogenesis Inhibitor 1 (BAI1) is a seven transmembrane G protein-coupled receptor (GPCR) with potent anti-angiogenic and anti-tumorigenic properties in gliomas. Our novel findings show that BAI1 expression is significantly reduced in human medulloblastoma (MB) by epigenetic mechanisms, leading us to hypothesize that loss of expression of BAI1 may favor tumor development during cerebellar development. To test this hypothesis, we generated a Bai1 knockout (KO) mouse and detected aberrant activation of Sonic hedgehog signaling and a thicker external granular layer during early postnatal cerebellum development. Furthermore, upon crossing the Bai1 KO mice with mice heterozygous for patched 1 (ptc1 + /-), we found that deficiency of Bai1 dramatically accelerated MB tumorigenesis, the first demonstration that a reduction in Bai1 dosage can promote MB formation in vivo. Moreover, restoration of BAI1 expression in human MB cells inhibited cell growth both in vitro and in vivo. These results support that BAI1 is a novel tumor suppressor for MB and that down-regulation of BAI1 in the cerebellum may drive inappropriate downstream growth signaling and contribute to neoplastic transformation leading to the formation of MB. To further elucidate the molecular mechanisms, we are currently exploring the Bai1 downstream signaling involved in MB tumorigenesis and will present the related findings. Our results also suggest that restoration of BAI1 expression may represent a novel therapeutic intervention for MB. Specifically, we demonstrate that small molecule epigenetic inhibitors of either EZH2 or MBD2 can reactivate BAI1 expression. Taken together, our novel findings provide insight into the neurobiological mechanisms underlying MB tumorigenesis and provide the rationale for the use of epigenetic therapeutics against MB.

Identification of prohibitin 1 as a potential prognostic biomarker in human pancreatic carcinoma using modified aqueous two-phase partition system combined with 2D-MALDI-TOF-TOF-MS/MS.

Membrane proteins are an important source of potential targets for anticancer drugs or biomarkers for early diagnosis. In this study, we used a modified aqueous two-phase partition system combined with two-dimensional (2D) matrix-assisted laser desorption ionization (MALDI) time of flight (TOF) mass spectrometry (MS, 2D-MALDI-TOF-TOF-MS/MS) analysis to isolate and identify membrane proteins in PANC-1 pancreatic cancer cells. Using this method, we identified 55 proteins, of which 31 (56.4%) were membrane proteins, which, according to gene ontology annotation, are associated with various cellular processes including cell signal transduction, differentiation, and apoptosis. Immunohistochemical analysis showed that the expression level of one of the identified mitochondria membrane proteins, prohibitin 1 (PHB1), is correlated with pancreatic carcinoma differentiation; PHB1 is expressed at a higher level in normal pancreatic tissue than in well-differentiated carcinoma tissue. Further studies showed that PHB1 plays a proapoptotic role in human pancreatic cancer cells, which suggests that PHB1 has antitumorigenic properties. In conclusion, we have provided a modified method for isolating and identifying membrane proteins and demonstrated that PHB1 may be a promising biomarker for early diagnosis and therapy of pancreatic (and potentially other) cancers.

Abstract 4119: Novel evidence for chemopreventive effects of curcumin and boswellic acid through regulation of mir-27a and mir-34a in human colorectal cancer

Abstract Purpose: Colorectal cancer (CRC) is one of the most common causes of cancer-associated mortality worldwide, but it is truly a preventable disease. Accumulating evidence indicates that several dietary botanicals, including curcumin and boswellic acids, have potent anti-inflammatory and anti-tumorigenic properties. However, the molecular mechanisms underlying the anti-cancer potential of these compounds remain poorly understood. More recent data suggest that the chemopreventive effects of these botanicals may in part be mediated through regulation of key cancer-related microRNAs (miRNAs), and their downstream gene targets. This study aimed to determine whether curcumin and 3 acetyl-11-keto-β-boswellic acid (AKBA) exert their anti-tumorigenic effects through modulation of specific miRNAs in CRC cell lines and a xenograft mouse model. Experimental Design: We first determined the effects of curcumin and AKBA on cellular proliferation, apoptosis and cell cycle dynamics in a panel of CRC cell lines. Next, we used Illumina's Human HT-12 V4 array gene expression arrays to systematically identify specific gene signaling pathways regulated by curcumin and AKBA. Subsequently we used combined bioinformatics and in-silico approaches to identify miRNAs and molecular pathways activated by curcumin and AKBA individually, and their combination. We determined the functional role of curcumin and AKBA-related miRNAs in CRC cell lines, and validated these findings for the chemopreventive efficacy of curcumin and AKBA in a xenograft animal model. Results: Both curcumin and AKBA inhibited cellular proliferation, induced apoptosis and cell cycle arrests in all CRC cell lines, and these effects were significantly enhanced with combined vis-à-vis individual treatments with the botanicals. Gene-expression arrays revealed that curcumin and AKBA regulated key cell cycle controlling genes including: cMYC, CCND1, CCNE1 and CDK4. Combined bioinformatics and in-silico analysis identified apoptosis, proliferation and cell cycle regulatory signaling pathways as the key modulators of curcumin and AKBA-induced anti-cancer effects, and further discovered miR-27a and miR-34a as the most significantly differentially expressed miRNAs following treatment with the two botanicals. In support of our in vitro findings, mouse xenograft experiments further confirmed that both curcumin and AKBA suppressed tumor size and volume in mice, and that these effects were orchestrated through modulation of miR-27a and miR-34a expression in the animal model. Conclusion: We provide novel mechanistic evidence for the chemopreventive effects of curcumin and AKBA through regulation of specific miRNAs in CRC. The enhanced anti-tumorigenic effect by combined treatment with these botanicals provides a potential rationale for the use of such diet-based botanicals for the chemoprevention of this malignancy. Citation Format: Shusuke Toden, Yoshinaga Okugawa, Keun Hur, Thomas A. Jascur, Constanze Burhrmann, Durgha Nattamai, Esperanza Anguiano, Mehdi Shakibaei, C. Richard Boland, Ajay Goel. Novel evidence for chemopreventive effects of curcumin and boswellic acid through regulation of mir-27a and mir-34a in human colorectal cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4119. doi:10.1158/1538-7445.AM2014-4119

Abstract 410: Epigallocatechin gallate inhibits colon cancer cell proliferation by modulating epigenetic enzymes (DNMTs, HDACs, and HATs)

Abstract Epigallocatechin gallate (EGCG), a major constituent of green tea, has been shown to exhibit antioxidant and antitumorigenic properties using in vitro and in vivo models of colon cancer and in small cohort studies of colorectal cancer patients. The development of colon cancer is influenced by both genetic and epigenetic factors, with increased risk associated with age, lifestyle, and environmental exposures. Thus, parsing the interactions of genetic components and epigenetic modulators of gene expression in colon cancer development and progression is essential. The mechanism by which EGCG exerts antitumorigenic activity against colon cancer has not been completely elucidated. This study investigates potential mechanism(s) by which EGCG inhibits proliferation of HCT-116 and HT-29 colon cancer cell lines, via epigenetic pathways. Briefly, HCT-116 and HT-29 cells were treated with EGCG (5-150 µM) and control drugs: 5-FU (50-200 µg/mL), 5-AZA (5 µM), SAHA (1-10 µM), and anacardic acid (10 µM) for 48-72 h. Cell proliferation (MTT), cell cycle and apoptosis (PI-FC and TUNEL), enzyme activity, gene and protein expression were measured. EGCG inhibited proliferation of HCT-116 and HT-29 by promoting S-phase cell cycle arrest and apoptosis. Expression and global enzyme activity of DNMTs (1, 3a, 3b), HDACs (1-4), and HATs (P300, PCAF, P400) were differentially expressed in both cell lines. A consistent upregulation of DNMT3b and downregulation of HDAC3 in both cell lines were observed. Global and gene-specific regulation of DNA methylation and histone acetylation by EGCG is under current study in our lab. The antiproliferative effects of EGCG can potentially be attributed to restoring normal global and gene-specific methylation/acetylation pattern in colon cancer cells by regulating DNMTs, HDACs, and HATs. This study provides evidence for the utilization of EGCG as a potential chemopreventive agent against colon cancer. Furthermore, identifying mechanisms by which EGCG overrides tumor-driven genetic deregulation to inhibit carcinogenesis expands our knowledge on pathways contributing to colon cancer and plausible targets for epigenetic therapy/prevention. This project is supported by NIH: RO1CA96694 and P30CA054174. Citation Format: April B. Cabang, Yuan Fang, Jay Morris, Michael J. Wargovich. Epigallocatechin gallate inhibits colon cancer cell proliferation by modulating epigenetic enzymes (DNMTs, HDACs, and HATs). [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 410. doi:10.1158/1538-7445.AM2014-410

Recovery and purification of oligosaccharides from copra meal by recombinant endo-β-mannanase and deciphering molecular mechanism involved and its role as potent therapeutic agent.

Production of manno-oligosaccharides (MOSs) from pretreated and defatted copra meal (dFCO) hydrolysis was achieved by endo-mannanase. Structural characterization of dFCO by FT-IR and NMR exhibited resemblance with galactomannan. The time-dependent hydrolysis of dFCO by recombinant endo-β-(1 → 4)-mannanase of Clostridium thermocellum by TLC and HPAEC displayed the release of mannose and MOSs mannobiose and mannotriose. Purified MOSs yielded 40 % mannobiose and 18 % mannotriose confirmed by mass spectroscopy which showed mannobiose (m/z = 365) and mannotriose (m/z = 527). The homology based structural analysis of catalytic endo-mannanase (CtManT) showed the catalytic core composed of Glu181 and Glu300 acting as acid/base and Glu288 as a nucleophile during galactomannan hydrolysis. Sub-site mapping of CtManT exhibited two aglycone and four glycone sites at cleavage sites existing on either side of β-(1 → 4)-linkage of galactomannan. Isolated MOSs displayed potential prebiotic characteristics and supported higher growth of probiotic Lactobacillus acidophilus and Bifidobacterium infantis than with standard inulin. Moreover, MOSs displayed over 97 % tolerance to simulated gastric juice, intestinal fluid, and α-amylase proving its potential as a stable prebiotic over inulin. In vitro cytotoxicity assay of MOSs (500 µg/mL) on human epithelial colorectal adenocarcinoma cell line (HT-29) demonstrated 60 % decreased viability of cells after 48 h displaying anti-tumorigenic property.

The cytoskeletal inhibitors latrunculin A and blebbistatin exert antitumorigenic properties in human hepatocellular carcinoma cells by interfering with intracellular HuR trafficking

The impact of the RNA-binding protein HuR for the post-transcriptional deregulation of tumor-relevant genes is well established. Despite of elevations in HuR expression levels, an increase in cytoplasmic HuR abundance in many cases correlates with a high grade of malignancy. Here, we demonstrated that administration of the actin-depolymerizing macrolide latrunculin A, or blebbistatin, an inhibitor of myosin II ATPase activity, caused a dose- and time-dependent reduction in the high cytoplasmic HuR content of HepG2 and Huh7 hepatocellular carcinoma (HCC) cells. Subcellular fractionation revealed that in addition, both inhibitors strongly attenuated cytoskeletal and membrane-bound HuR abundance and conversely increased the HuR amount in nuclear cell fractions. Concomitant with changes in intracellular HuR localization, both cytoskeletal inhibitors markedly decreased the half-lives of cyclooxygenase-2 (COX-2), cyclin A and cyclin D1 encoding mRNAs resulting in a significant reduction in their expression levels in HepG2 cells. Importantly, a similar reduction in the expression of these HuR targets was achieved by a RNA interference (RNAi)-mediated knockdown of either HuR or nonmuscle myoin IIA. Using polysomal fractionation, we further demonstrate that the decrease in cytoplasmic HuR by latrunculin A or blebbistatin is accompanied by a marked change in the allocation of HuR and its mRNA cargo from polysomes to ribonucleoprotein (RNP) particles. Functionally, the basal migration and prostaglandin E2 synthesis are similarly impaired in inhibitor-treated and stable HuR-knockdown HepG2 cells. Our data demonstrate that interfering with the actomyosin-dependent HuR trafficking may comprise a valid therapeutic option for antagonizing pathologic posttranscriptional gene expression by HuR and furthermore emphasize the potential benefit of HuR inhibitory strategies for treatment of HCC.

Protective role of luteolin against cognitive dysfunction induced by chronic cerebral hypoperfusion in rats

Chronic cerebral hypoperfusion, a mild ischemic condition, is associated with the cognitive deficits of Alzheimer's disease (AD). Luteolin, a polyphenolic compound found in foods of plant origin, belonging to the flavone subclass of flavonoids, has been shown to possess antioxidant, anti-inflammatory and antitumorigenic properties. In the present study, the effects of luteolin on chronic cerebral hypoperfusion-associated neurocognitive pathologies were investigated by using rats with permanent bilateral common carotid artery occlusion, a rat model of chronic cerebral hypoperfusion. As expected, we found that luteolin could attenuate cognitive dysfunction in chronic cerebral hypoperfused rats, as assessed using Morris water maze tests. Daily oral administration of luteolin (50, 100 and 200mg/kg) significantly scavenged oxygen free radicals, enhanced antioxidant potential, decreased the lipid peroxide production and suppressed inflammatory reaction in the cerebral cortex and hippocampus induced by chronic cerebral hypoperfusion. Meanwhile, the results indicated that cerebral hypoperfusion activated nuclear factor-κB (NF-κB), increased the expression of β-site amyloid precursor protein cleaving enzyme (BACE1), as well as elevated amyloid beta (Aβ) levels in the cortex and hippocampus. However, long-term administration of luteolin significantly down-regulated the expression of NF-κB and BACE1, accompanied by diminishing the deposition of Aβ. Our results suggest a potential therapeutic use of luteolin for cerebral hypoperfusion associated cognitive dysfunction in AD.

Expression of programmed cell death 5 protein inhibits progression of lung carcinoma in vitro and in vivo via the mitochondrial apoptotic pathway

Lung cancer is one of the most common and serious types of cancer, and is characterized by uncontrolled cell growth and metastasis from lung tissues to other body parts. The programmed cell death 5 (Pdcd5) protein is known to accelerate apoptosis in different cell types of tumor. The aim of the present study was to explore the role of Pdcd5 in lung carcinoma and to identify the mechanisms underlying the antitumorigenic properties of Pdcd5 in lung cancer. First, we detected and compared the expression of Pdcd5 in healthy and highly differentiated adenocarcinoma lung tissues. The results of histochemical staining and western blot analysis demonstrated that Pdcd5 expression is markedly decreased in highly differentiated lung adenocarcinoma. Next, we used the lung adenocarcinoma cell line A549 to study the effects of Pdc5 expression on proliferation and colony formation. The results revealed that the expression of Pdcd5 significantly inhibits cell proliferation and colony formation in A549 cells. Importantly, Pdcd5 expression induced tumor cell apoptosis, and the apoptotic proteins caspase-3 and -9 were activated. The expression of B-cell lymphoma 2 (Bcl-2) was reduced and that of Bcl2‑associated X protein (Bax) was increased, overall suggesting that the intrinsic apoptotic pathway is activated. Furthermore, using a mice xenograft model and vectors for stable expression or silencing of Pdcd5, we showed that stable expression of the protein significantly increases the survival rate of mice in vivo (P<0.01 compared to control). In conclusion, both in vitro and in vivo experiments demonstrated that Pdcd5 expression inhibits proliferation and induces apoptosis in the A549 cell line, indicating that the Pdcd5 protein may play an important role in the progression of lung cancer. Therefore, Pdcd5 may be a promising target for the therapy of lung carcinoma.

Anticancer activities of mushroom polysaccharides on chemically-induced colorectal cancer in rats

Polysaccharides from mushroom Pleurotus sajor-caju (PS1) and Lactuca Sativa (PS2) were isolated and purified (22.40 and 26.80g/100g respectively). Cytotoxic activities of PS1 and PS2 were examined in vitro using colon (HCT 116), liver (HEPG2), cervical (HELA) and breast (MCF7) carcinoma cell lines. The present results indicated that these polysaccharides (PS1 andPS2) have more inhibitory effects on HCT-116 than the other carcinoma cell line (HEPG2, HELA and MCF7). Polysaccharides (PS1 and PS2)-treated HCT-116 cells showed a high percentage of cell death, indicating promising anti-tumorigenic properties, and demonstrate their direct effect on colon cancer cell proliferation. Evaluation of the two polysaccharides (PS1and PS2) was carried out through determination of the tumor markers (CEA and C19.9) in cancer rat groups treated with either PS1 or PS2 compared versus carcinogenic control rats. Polysaccharides (PS2) administration caused higher inhibitory effect on chemically-induced colorectal cancer in rats through the histological examination and a marked reduction in the levels of ALP and ALT more than that of PS1 in serum of rats. It can be concluded that polysaccharides (PS1 and PS2) are more effective for inhibition of chemically induced colorectal cancer in rats.