• Korean Journal of Medicinal Crop Science
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• v.10 no.5
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• pp.403-408
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• 2002

We prepared extracts from bark, leaf and fruit of Sorbus commixta Hedl using by water and ethanol. To test for mutagenicity and antimutagenicity on extracts, we used Rec assay and Ames test. The result of Rec assay, the extracts of the Sorbus commixta Hedl did not show a DNA-damage activity. The results of Ames test were provided that extracts of Sorbus commixta Hedl showed $43{\sim}73\;%$ antimutagenic activities. In the inhibition ratio of the growth of several human cancer cells (A549, HepG2, MCF7), 91% of MCF7 cell growth, 94% of A549 cell growth and 91% HepG2 cell growth were inhibited by adding 1mg/ml of fruit ethanol extracts, bark ethanol extracts and fruit ethanol extracts, respectively. There was a little cytotoxicity on human normal hephatocyte (WRL68), extracts(1mg/ml) showed over the 70% survival.

• The Korean Journal of Physiology and Pharmacology
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• v.26 no.6
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• pp.457-468
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• 2022

It has been demonstrated that APPL1 (adaptor protein, phosphotyrosine interacting with PH domain and leucine zipper 1) is involved in the regulation of several growth-related signaling pathways and thus closely associated with the development and progression of some cancers. Diallyl trisulfide (DAT), a garlic-derived bioactive compound, exerts selective cytotoxicity to various human cancer cells through interfering with pro-survival signaling pathways. However, whether and how DAT affects survival of human hepatocellular carcinoma (HCC) cells remain unclear. Herein, we tested the hypothesis of the involvement of APPL1 in DAT-induced cytotoxicity in HCC HepG2 cells. We found that Lys 63 (K63)-linked polyubiquitination of APPL1 was significantly decreased whereas phosphorylation of APPL1 at serine residues remained unchanged in DAT-treated HepG2 cells. Compared with wild-type APPL1, overexpression of APPL1 K63R mutant dramatically increased cell apoptosis and mitigated cell survival, along with a reduction of phosphorylation of STAT3, Akt, and Erk1/2. In addition, DAT administration markedly reduced protein levels of intracellular TNF receptor-associated factor 6 (TRAF6). Genetic inhibition of TRAF6 decreased K63-linked polyubiquitination of APPL1. Moreover, the cytotoxicity impacts of DAT on HepG2 cells were greatly attenuated by overexpression of wild-type APPL1. Taken together, these results suggest that APPL1 polyubiquitination probably mediates the inhibitory effects of DAT on survival of HepG2 cells by modulating STAT3, Akt, and Erk1/2 pathways.

• Journal of Life Science
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• v.17 no.10
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• pp.1447-1451
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• 2007

Through the screening of marine natural compounds that inhibit cancer cell proliferation, we previously reported that pectenotoxin-2 (PTX-2) isolated from marine sponges exhibits selective cytotoxicity against several cell lines in p53-deficient tumor cells compared to those with functional p53. However, the molecular mechanisms of its anti-proliferative action on malignant cell growth are not completely known. To further explore the mechanisms of its anti-cancer activity and to test whether the status of p53 in liver cancer cells correlates with their chemo-sensitivities to PTX-2, we used two well-known hepatocarcinoma cell lines, p53-deficient Hep3B and p53-wild type HepG2. We have demonstrated that PTX-2 markedly inhibits Hep3B cell growth and induces apoptosis whereas HepG2 cells are much more resistant to PTX-2 suggesting that PTX-2 seems to act by p53-independent cytotoxic mechanism. The apoptosis induced by PTX-2 in Hep3B cells was associated with the modulation of DNA fragmentation factor (DFF) family proteins, up-regulation of pro-apoptotic Bcl-2 family members such as Bax and Bcl-xS and activation of caspases (caspase-3, -8 and -9). Blockade of the caspase-3 activity by caspase-3 inhibitor, z-DEVD-fmk, prevented the PTX-2-induced growth inhibition in Hep3B cells. Moreover, treatment with PTX-2 also induced phosphorylation of AKT and extracellular-signal regulating kinase (ERK), but not c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MARK). Specific inhibitors of PI3K inhibitor (LY294002) and ERK1/2 inhibitor (PD98059) significantly blocks PTX-2-induced-anti-proliferative effects, whereas a JNK inhibitor (SP600125) and a p38 MAPK inhibitor (SB203580) have no significant effects demonstrating that the pro-apoptotic effect of PTX-2 mediated through activation of AKT and ERK signal pathway in Hep3B cells.

• Archives of Pharmacal Research
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• v.28 no.11
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• pp.1270-1274
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• 2005

The vascular endothelial growth factor (VEGF) plays a key role in angiogenesis, which is a process where new blood vessels develop from the endothelium of a pre-existing vasculature. VEGF exerts its activity by binding to its receptor tyrosine kinase, KDR/Flk-1, which is expressed on the surface of endothelial cells. A methanol extract and organic solvent (n-hexane, ethyl acetate, n-butanol, aqueous) fractions from Rubus coreanus were examined for their inhibitory effects on VEGF binding to the VEGF receptor. The methanol extract from the crude drug were found to significantly inhibit VEGF binding to the VEGF receptor ($IC_{50}$$\thickapprox$27 $\mu$g/mL). Among the fractions examined, the aqueous fraction from the medicinal plant showed potent inhibitory effects against the binding of KDR/Flk-1-Fc to immobilized $VEGF_{165}$ in a dose­dependent manner ($IC_{50}$$\thickapprox$11 $\mu$g/mL). Sanguiin H-6 was isolated as an active principle from the aqueous fraction, and inhibited the binding of KDR/Flk-1-Fc to immobilized $VEGF_{165}$ in a dose­dependent manner ($IC_{50}$$\thickapprox$0.3 $\mu$g/mL). In addition, sanguiin H-6 efficiently blocked the VEGF­induced HUVEC proliferation in a dose-dependent manner ($IC_{50}$$\thickapprox$7.4 $\mu$g/mL) but had no effect on the growth of HT1080 human fibrosarcoma cells. This suggests that sanguiin H-6 might be a potential anti-angiogenic agent.

• Journal of Life Science
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• v.26 no.2
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• pp.265-274
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• 2016

Toxin-antitoxin (TA) systems are ubiquitous genetic modules that are evolutionally conserved in bacteria and archaea. TA systems composed of an intracellular toxin and its antidote (antitoxin) are currently classified into five types. Commonly, activation of toxins under stress conditions inhibits diverse cellular processes and consequently induces cell death or reversible growth inhibition. These effects of toxins play various physiological roles in such as regulation of gene expression, growth control (stress response), programmed cell arrest, persister cells, programmed cell death, phage protection, stabilization of mobile genetic elements or postsegregational killing of plasmid-free cells. Accordingly, bacterial TA systems are commonly considered as stress-responsive genetic modules. However, molecule screening for activation of toxin in TA system is available as development of antimicrobial agents. In addition, cytotoxic effect induced by toxin is used as effective cloning method with antitoxic effect of antitoxin; consequently cells containing cloning vector inserted a target gene can survive and false-positive transformants are removed. Also, TA system is applicable to efficient single protein production in biotechnology industry because toxins that are site-specific ribonuclease inhibit protein synthesis except for target protein. Furthermore, some TA systems that induce apoptosis in eukaryotic cells such as cancer cells or virus-infected cells would have a wide range of applications in eukaryotes, and it will lead to new ways of treating human disease. In this review, we summarize the current knowledge on bacterial TA systems and their applications.

• Journal of Life Science
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• v.24 no.10
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• pp.1137-1143
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• 2014

Doxorubicin is a general chemotherapy drug widely used for a number of cancers. However, the correlation between endogenous nitric oxide ($NO^{\bullet}$) levels and chemoresistance to doxorubicin remains unclear. In this study, we investigated the effect of endogenous $NO^{\bullet}$ on the anticancer activity of doxorubicin in human colon cancer cell lines HCT116 and HT29 with different p53 status. The cells were treated with either doxorubicin alone or in combination with the $NO^{\bullet}$ synthase (NOS) inhibitor $N^G$-monomethyl-L-arginine (NMA). Doxorubicin differentially inhibited the growth of both the HCT116 (p53-WT) and HT29 (p53-MUT) cells, which was mitigated by cotreatment with NMA. Further studies revealed that inhibition of endogenous $NO^{\bullet}$ mitigated doxorubicin-induced apoptosis in the HCT116 and HT29 cells, as evidenced by apoptotic DNA fragmentation and the sub-G1 peak of apoptotic markers. Apoptosis was delayed in the HT29 cells, and its magnitude was greatly reduced, underscoring the importance of the modulation of p53 in the response. RT-PCR analysis revealed that doxorubicin down-regulated levels of inhibitors of the apoptosis family (cellular IAP-1 and-2). Collectively, these data show that induction of apoptosis by doxorubicin in human colon cancer cells is possibly related to modulation of endogenous $NO^{\bullet}$, the expression of the IAP family of genes, and the status of p53. The underlying mechanisms may represent potential targets for adjuvant strategies to improve the efficacy of chemotherapy for colon cancer.

• Journal of Life Science
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• v.21 no.6
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• pp.893-900
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• 2011

Prostatic acid phosphatase (PAP) is one of the widely used biomarkers in the diagnosis of prostate cancer. It was initially identified in 1935 and is the most abundant phosphatase in the human prostate. PAP is a prostate-specific enzyme that is synthesized in prostate epithelial cells. It belongs to the acid phosphatase group that shows enzymatic activity in acidic conditions. PAP is abundant in prostatic fluid and is thought to have a role in fertilization and oligospermia. It also has a potential role in reducing chronic pain. But one of the most apparent functions of PAP is the dephosphorylation of macromolecules such as HER-2 and PI3P that are involved in the ERK1/2 and MAPK pathways, which in turn leads to inhibition of cell growth and tumorigenesis. Currently, clinical trials using PAP DNA vaccine are underway and FDA-approved immunotherapy using PAP is commercially available. Despite these clinically important aspects, molecular mechanisms underlying PAP regulation are not fully understood. The promoter region of PAP was reported to be regulated by NF-${\kappa}B$, TNF-${\alpha}$, IL-1, androgen and androgen receptors. Here, the features of PAP gene and protein structures together with the function, regulation and roles of PAP in prostate cancer are discussed.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.12
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• pp.4773-4780
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• 2014

Background: To investigate the effects of small interference RNA (siRNA) targeting BCR/ABL mRNA on proliferation and apoptosis in the K562 human chronic myeloid leukemia (CML) cell line and to provide a theoretical rationale and experimental evidence for its potential clinical application for anti-CML treatment. Materials and Methods: The gene sequence for BCR/ABL mRNA was found from the GeneBank. The target gene site on the BCR/ABL mRNA were selected according to Max-Planck-Institute (MPI) and rational siRNA design rules, the secondary structure of the candidate targeted mRNA was predicted, the relevant thermodynamic parameters were analyzed, and the targeted gene sequences were compared with BLAST to eliminate any sequences with significant homology. Inhibition of proliferation was evaluated by MTT assay and colony-formation inhibiting test. Apoptosis was determined by flow cytometry (FCM) and the morphology of apoptotic cells was identified by Giemsa-Wright staining. Western blotting was used to analyze the expression of BCR/ABL fusion protein in K562 cells after siRNA treatment. Results: The mRNA local secondary structure calculated by RNA structure software, and the optimal design of specific siRNA were contributed by bioinformatics rules. Five sequences of BCR/ABL siRNAs were designed and synthesized in vitro. Three sequences, siRNA1384, siRNA1276 and siRNA1786, which showed the most effective inhibition of K562 cell growth, were identified among the five candidate siRNAs, with a cell proliferative inhibitory rate nearly 50% after exposure to 12.5nmol/L~50nmol/L siRNA1384 for 24,48 and 72 hours. The 50% inhibitory concentrations ($IC_{50}$) of siRNA1384, siRNA1276 and siRNA1786 for 24hours were 46.6 nmol/L, 59.3 nmol/L and 62.6 nmol/L, respectively, and 65.668 nmol/L, 76.6 nmol/L, 74.4 nmol/L for 72 hours. The colony-formation inhibiting test also indicated that, compared with control, cell growth of siRNA treated group was inhibited. FCM results showed that the rate of cell apoptosis increased 24 hours after transfecting siRNA. The results of annexinV/PI staining indicated that the rate of apoptosis imcreased (1.53%, 15.3%, 64.5%, 57.5% and 21.5%) following treamtne with siRNAs (siRNA34, siRNA372, siRNA1384, siRNA1276 and siRNA1786). Morphological analysis showed td typical morphologic changes of apoptosis such as shrunken, fragmentation nucleus as well as "apoptotic bodies" after K562 cell exposure to siRNA. Western blot analysis showed that BCR/ABL protein was reduced sharply after a single dose of 50nmol/L siRNA transfection. Conclusions: Proliferation of K562 cells was remarkbly inhibited by siRNAs (siRNA1384, siRNA1276 and siRNA1786) in a concentration-dependent manner in vitro, with effective induction of apoptosis at a concentration of 50 nmol/L. One anti-leukemia mechanism in K562 cells appeared that BCR/ABL targeted protein was highly down-regulated. The siRNAs (siRNA1384, siRNA1276 and siRNA1786) may prove valuable in the treatment of CML.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.29 no.5
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• pp.272-281
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• 2003

Nontraditional or alternative medicine is becoming an increasingly attractive approach for the treatment of various inflammatory disorders and cancers. Curcumin is the major constitute of turmoric powder extracted from the rhizomes of the plant Curcuma longa. Resveratrol is a phytoalexin present in grapes and a variety of medicinal plants. In this report, We investigated the effect of curcumin and resveratrol on regulatory protein of cell cycle, induction of apoptosis and MMP activity. Treatment with 75 M curcumin for 24 hrs produced morphological changing in HN-4 cells. Curcumin and resveratrol inhibited the cellular growth in HN-4 cells. Inhibition of cell growth was associated with down-regulation of cell cycle regulatory proteins. Curcumin-induced caspase-3 activation and Bax degradation were dose-dependent with a maximal effect at a concentration of 100 M. The elevated caspase-3 activity in curcumin treated HN-4 cells are correlated with down-regulation of survivin and cIAP1, but not cIAP2. Curcumin induced a dose-dependent increase of cytochrome c in the cytosol. Curcumin induced-apoptosis was mediated through the release of cytochrome c. In addition, curcumin-induced apoptosis was caused by the generation of reactive oxygen species, which was prevented by antioxidant N-acetyl-cysteine (NAC). Cotreatment with NAC markedly prevented cytochrome c release, Bax cleavage and cell death. Also resveratrol-induced apoptosis was preceded by down-regulation of the anti-apoptotic Bcl-2, cIAP1, and caspase-3 activity. However, resveratrol-induced apoptosis was not prevented by antioxidant NAC. In addition, HN-4 cells release basal levels of MMP2 when cultured in serum-free medium. Treatment of the cells with various concentrations of PMA for 24 hr induced the expression and secretion of latent MMP9 as determined by gelatin zymography. HN-4 cells were treated with various concentrations of curcumin and resveratrol in the presence of 75 nM PMA, and MMP2 and 9 activities were inhibited by curcumin and resveratrol. These findings have implications for developing curcumin-based anticancer and anti-inflammation therapies.

• Radiation Oncology Journal
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• v.22 no.2
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• pp.77-90
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• 2004

Purpose: The purpose of this review Is to provide an update on novel radiation treatments for head and neck cancer Recent Findings: Despite the remarkable advances In chemotherapy and radiotherapy techniques, the management of advanced head and neck cancer remains challenging. Epidermal growth factor receptor (EGFR) Is an appealing target for novel therapies In head and neck cancer because not only EGFR activation stimulates many important signaling pathways associated with cancer development and progression, and importantly, resistance to radiation. Furthermore, EGFR overexpression Is known to be portended for a worse outcome in patients with advanced head and neck cancer. Two categories of compounds designed to abrogate EGFR signaling, such as monoclonal antibodies (Cetuxlmab) and tyrosine kinase inhibitors (ZD1839 and 051-774) have been assessed and have been most extensively studied In preclinical models and clinical trials. Additional TKIs In clinical trials include a reversible agent, Cl-1033, which blocks activation of all erbB receptors. Encouraging preclinical data for head and neck cancers resulted In rapid translation Into the clinic. Results from Initial clinical trials show rather surprisingly that only minority of patients benefited from EGFR inhibition as monotherapy or In combination with chemotherapy. In this review, we begin with a brief summary of erbB- mediated signal transduction. Subsequently, we present data on prognostic-predictive value of erbB receptor expression in HNC followed by preclinlcal and clinical data on the role of EGFR antagonists alone or in combination with radiation In the treatment of HNC. Finally, we discuss the emerging thoughts on resistance to EGFR biockade and efforts In the development of multiple-targeted therapy for combination with chemotherapy or radiation. Current challenges for investigators are to determine (1 ) who will benefit from targeted agents and which agents are most appropriate to combine with radiation and/or chemotherapy, (2) how to sequence these agents with radiation and/or cytotoxlc compounds, (3) reliable markers for patient selection and verification of effective blockade of signaling in vivo, and (4) mechanisms behind intrinsic or acquired resistance to targeted agents to facilitate rational development of multi-targeted therapy, Other molecuiar-targeted approaches In head and neck cancer were briefly described, Including angloenesis Inhibitors, farnesyl transferase inhibitors, cell cycle regulators, and gene therapy Summary: Novel targeted theraples are highly appealing in advanced head and neck cancer, and the most premising strategy to use them Is a matter of intense Investigation.