Ji Ho Yun

Induction of the Phase II Detoxification Enzyme NQO1 in Hepatocarcinoma Cells by Lignans from the Fruit of Schisandra chinensis through Nuclear Accumulation of Nrf2

The upregulation of phase II detoxification genes is believed to play an important role in cancer prevention. The molecular mechanism underlying the changes in gene expression that accompany cancer prevention involves activation of the transcription factor, NF-E2-related factor 2 (Nrf2). In traditional medicine, the fruit of Schisandra chinensis Baill is used as a tonic, an anti-tussive and an anti-aging drug. In the current study, nine lignans were isolated from S. chinensis and tested for their ability to induce quinone reductase (QR) activity in Hepa1c1c7 mouse hepatocarcinoma cells. Tigloylgomisin H (TGH) and angeloylgomisin H (AGH) significantly induced QR activity and exhibited a relatively high chemoprevention index (CI) (10.80 and 4.59, respectively) as compared to control. TGH also induced QR activity in BPrc1 mouse hepatocarcinoma cells as well, which are defective in aryl hydrocarbon nuclear translocator (Arnt). In HepG2 human hepatocarcinoma cells, TGH significantly activated gene expression mediated by the antioxidant response element (ARE), a key regulatory region in the promoters of detoxification enzymes, through the nuclear accumulation of Nrf2. The results of the current study suggest that TGH functions as a novel monofunctional inducer that specifically upregulates phase II enzymes through the Nrf2-ARE pathway. TGH thus represents a potential liver cancer prevention agent.

Youngia denticulata Protects Against Oxidative Damage Induced by tert-Butylhydroperoxide in HepG2 Cells

Improvement of liver function is one of the most popular commercial health claims of functional foods in Asian countries, including Korea. After examining the potential of several traditional Korean wild vegetables for enhancing liver function, we found that Youngia denticulata Kitam. has strong hepatoprotective effects against oxidative stress induced by tert-butylhydroperoxide (t-BHP). We are the first to report that the extract and ethyl acetate fractions of Y. denticulata have radical scavenging activities and inhibit oxidative stress-induced cell death and DNA damage in HepG2 cells. The extract and ethyl acetate fractions significantly decreased cellular reactive oxygen species production and apoptosis induced by t-BHP in HepG2 cells. In addition, they prevented the depletion of cellular glutathione, which is an important defense molecule against oxidizing xenobiotics. Chlorogenic acid and 3,5-dicaffeoylquinic acid were found to be major active components responsible for the activity of Y. denticulata and could serve as marker compounds for standardization. These data suggest that Y. denticulata could be promoted as a potential antioxidative functional food candidate, particularly for hepatoprotection against oxidative stress.

A polyacetylene from Gymnaster koraiensis exerts hepatoprotective effects in vivo and in vitro.

In the present study, we isolated a polyacetylene, gymnasterkoreayne B (GKB), from Gymnaster koraiensis and investigated the effect of GKB on the protection from oxidative stress-induced cytotoxicity through induction of the expression of cellular defense enzymes. GKB induced mRNA expression and enzyme activity of NAD(P)H:quinone oxidoreductase (NQO1) in vitro and in vivo, and potently increased expression of many cellular defense genes including glutathione-S-transferases, UDP-glucuronosyltransferase, and glutathione reductase (GSR) in normal rat liver. The nuclear factor erythroid 2-related factor 2 (Nrf2) which is known to induce various antioxidant and cytoprotective genes, and the genes containing the antioxidant response element (ARE), including NQO1, hemeoxygenease-1, GSR were induced by GKB in HepG2 human hepatocarcinoma cells. Pre-treatment of the cells with GKB accelerated the production of glutathione and mitigated menadione-induced cytotoxicity in HepG2 cells. Taken together, we found that GKB was a novel inducer of phase II detoxification enzymes and cellular defense enzymes, resulting in protection of the cells from oxidative stress and hepatotoxicity through regulation of detoxifying and antioxidant systems.

Antimicrobial Air Filters Using Natural Euscaphis japonica Nanoparticles

Controlling bioaerosols has become more important with increasing participation in indoor activities. Treatments using natural-product nanomaterials are a promising technique because of their relatively low toxicity compared to inorganic nanomaterials such as silver nanoparticles or carbon nanotubes. In this study, antimicrobial filters were fabricated from natural Euscaphis japonica nanoparticles, which were produced by nebulizing E. japonica extract. The coated filters were assessed in terms of pressure drop, antimicrobial activity, filtration efficiency, major chemical components, and cytotoxicity. Pressure drop and antimicrobial activity increased as a function of nanoparticle deposition time (590, 855, and 1150 µg/cm2filter at 3-, 6-, and 9-min depositions, respectively). In filter tests, the antimicrobial efficacy was greater against Staphylococcus epidermidis than Micrococcus luteus; ~61, ~73, and ~82% of M. luteus cells were inactivated on filters that had been coated for 3, 6, and 9 min, respectively, while the corresponding values were ~78, ~88, and ~94% with S. epidermidis. Although statistically significant differences in filtration performance were not observed between samples as a function of deposition time, the average filtration efficacy was slightly higher for S. epidermidis aerosols (~97%) than for M. luteus aerosols (~95%). High-performance liquid chromatography (HPLC) and electrospray ionization-tandem mass spectrometry (ESI/MS) analyses confirmed that the major chemical compounds in the E. japonica extract were 1(ß)-O-galloyl pedunculagin, quercetin-3-O-glucuronide, and kaempferol-3-O-glucoside. In vitro cytotoxicity and disk diffusion tests showed that E. japonica nanoparticles were less toxic and exhibited stronger antimicrobial activity toward some bacterial strains than a reference soluble nickel compound, which is classified as a human carcinogen. This study provides valuable information for the development of a bioaerosol control system that is environmental friendly and suitable for use in indoor environments.

The chemopreventive effects of Carpesium abrotanoides are mediated by induction of phase II detoxification enzymes and apoptosis in human colorectal cancer cells.

Cancer chemoprevention is thought to occur either by blocking the initiation of or suppressing the promotion of carcinogenesis. Phase II detoxification enzymes are known to play important roles in cancer chemoprevention because they enhance cytoprotection through detoxification and elimination of activated carcinogens at tumor initiation. Apoptosis is one of the most important inhibitory targets for tumor promotion. In this study, we have investigated the cancer chemopreventive activity of the ethanolic extract of Carpesium abrotanoides (CAE). We found that CAE induced quinone reductase [also known as NAD(P)H:quinone oxidoreductase (NQO1)] activity, increased NQO1 mRNA and protein expression, and had a relatively high chemoprevention index (12.04). CAE also significantly activated the antioxidant response element through the nuclear accumulation of NF-E2-related factor 2 in HCT116. Interestingly, we also found that CAE induced apoptosis, as evidenced by the externalization of phosphatidylserine, increased sub-G(0)/G(1) content, chromatin condensation, poly(ADP-ribose) polymerase cleavage, and p53. These data suggest that the chemopreventive effects of C. abrotanoides can result from both the induction of phase II detoxification enzymes and from apoptosis. Thus, CAE could potentially be developed as a cancer chemopreventive agent for prevention or treatment of human cancers.

Crepidiastrum denticulatum Extract Protects the Liver Against Chronic Alcohol-Induced Damage and Fat Accumulation in Rats

Alcohol is a severe hepatotoxicant that causes liver abnormalities such as steatosis, cirrhosis, and hepatocarcinoma. Crepidiastrum denticulatum (CD) is a well-known, traditionally consumed vegetable in Korea, which was recently reported to have bioactive compounds with detoxification and antioxidant properties. In this study, we report the hepatoprotective effect of CD extract against chronic alcohol-induced liver damage in vivo. The rats that were given CD extract exhibited decreased alanine aminotransferase, aspartate aminotransferase, and γ-glutamyl transpeptidase activities, which are liver damage markers that are typically elevated by alcohol consumption. The results were confirmed by histopathology with hematoxylin and eosin staining. Chronic alcohol consumption induced the formation of alcoholic fatty liver. However, treatment with CD extract dramatically decreased the hepatic lipid droplets. Treatment with CD extract also restored the antioxidative capacity and lipid peroxidation of the liver that had been changed by alcohol consumption. Furthermore, treatment with CD extract normalized the activities of the antioxidative enzymes superoxide dismutase, catalase, glutathione reductase, and glutathione peroxidase, which had been decreased by alcohol consumption. The results indicate that CD extract has protective effects against chronic alcohol hepatotoxicity in rats by increasing the livers antioxidant capacity, and has potential as a dietary supplement intervention for patients with alcohol-induced liver damage.

Chikusetsusaponin IVa methyl ester induces cell cycle arrest by the inhibition of nuclear translocation of β-catenin in HCT116 cells

We demonstrate that chikusetsusaponin IVa methyl ester (CME), a triterpenoid saponin from the root of Achyranthes japonica, has an anticancer activity. We investigate its molecular mechanism in depth in HCT116 cells. CME reduces the amount of β-catenin in nucleus and inhibits the binding of β-catenin to specific DNA sequences (TCF binding elements, TBE) in target gene promoters. Thus, CME appears to decrease the expression of cell cycle regulatory proteins such as Cyclin D1, as a representative target for β-catenin, as well as CDK2 and CDK4. As a result of the decrease of the cell cycle regulatory proteins, CME inhibits cell proliferation by arresting the cell cycle at the G0/G1 phase. Therefore, we suggest that CME as a novel Wnt/β-catenin inhibitor can be a putative agent for the treatment of colorectal cancers.

Stellera chamaejasme and its constituents induce cutaneous wound healing and anti-inflammatory activities.

Stellera chamaejasme L. (Thymelaeaceae) is a perennial herb that is widely used in traditional Chinese medicine to treat tumours, tuberculosis and psoriasis. S. chamaejasme extract (SCE) possesses anti-inflammatory, analgesic and wound healing activities; however, the effect of S. chamaejasme and its active compounds on cutaneous wound healing has not been investigated. We assessed full-thickness wounds of Sprague-Dawley (SD) rats and topically applied SCE for 2 weeks. In vitro studies were performed using HaCaT keratinocytes, Hs68 dermal fibroblasts and RAW 264.7 macrophages to determine cell viability (MTT assay), cell migration, collagen expression, nitric oxide (NO) production, prostaglandin E2 (PGE2) production, inflammatory cytokine expression and β-catenin activation. In vivo, wound size was reduced and epithelisation was improved in SCE-treated SD rats. In vitro, SCE and its active compounds induced keratinocyte migration by regulating the β-catenin, extracellular signal-regulated kinase and Akt signalling pathways. Furthermore, SCE and its active compounds increased mRNA expression of type I and III collagen in Hs68 fibroblasts. SCE and chamechromone inhibited NO and PGE2 release and mRNA expression of inflammatory mediators in RAW 264.7 macrophages. SCE enhances the motility of HaCaT keratinocytes and improves cutaneous wound healing in SD rats.

MicroRNA sequencing detects miR-424-5p up-regulation in ovarian cancer stem cells

Cancer stem cells (CSCs) are cancer cells that possess the ability to undergo continuous proliferation and self-renewal. It has been postulated that CSCs are responsible for tumor growth, heterogeneity, invasion, metastasis, and recurrence. MicroRNAs (miRNAs), small non-coding RNAs of approximately 22 nucleotides, are known to be involved in the maintenance of CSCs. To gain insight into the role of miRNAs in CSCs, we investigated the differential expression of miRNAs in ovarian CSCs compared to non-CSCs. Ovarian CSCs were isolated from the human ovarian cancer cell line SK-OV-3 using two ovarian CSC-specific surface markers, CD44 and CD117. The expression levels of miRNAs in CSCs and non-CSCs were estimated by miRNA sequencing. We detected four up-regulated miRNAs (miR-29a-5p, miR-34c-5p, miR-106a-5p, and miR-424-5p) in ovarian CSCs, and miR-424-5p was validated by real-time qPCR. MiR-424-5p target genes were predicted using several validated target databases and computational algorithms. Pathway analysis indicated that most miR-424-5p target genes are involved in cancer-related biological pathways. Overall, these results suggest that miR-424-5p is a potential regulator of CSCs that endows human ovarian tissue with tumorigenic potential and thus represents a potential therapeutic target for human ovarian cancer.

Phenethyl isothiocyanate suppresses cancer stem cell properties in vitro and in a xenograft model

BACKGROUND Cancer stem cells (CSCs) are a subset of cells within the bulk of a tumor that have the ability to self-renew and differentiate, and are thus associated with cancer invasion, metastasis, and recurrence. Phenethyl isothiocyanate (PEITC) is a natural compound found in cruciferous vegetables such as broccoli and is used as a cancer chemopreventive agent; however, its effects on CSCs are little known. PURPOSE To evaluate the effect of PEITC on CSCs in this study by examining CSC properties. METHODS NCCIT human embryonic carcinoma cells were treated with PEITC, and the expression of pluripotency factors Oct4, Sox-2, and Nanog were evaluated by luciferase assay and western blot. Effect of PEITC on self-renewal capacity and clonogenicity were assessed with the sphere formation, soft agar assay, and clonogenic assay in an epithelial cell adhesion molecule (EpCAM)-expressing CSC model derived from HCT116 colon cancer cells using a cell sorting system. The effect of PEITC was also investigated in a mouse xenograft model obtained by injecting nude mice with EpCAM-expressing cells. RESULTS We found that PEITC treatment suppressed expression of the all three pluripotency factors in the NCCIT cells, in which pluripotency factors are highly expressed. Moreover, PEITC suppressed the self-renewal capacity and clonogenicity in the EpCAM-expressing CSC model. EpCAM was used as a specific CSC marker in this study. Importantly, PEITC markedly suppressed both tumor growth and expression of three pluripotency factors in a mouse xenograft model. CONCLUSION These results demonstrate that PEITC might be able to slow down or prevent cancer recurrence by suppressing CSC stemness.