• Title/Summary/Keyword: Anti-tumor agents

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Induction of Apoptosis by Pectenotoxin-2 Isolated from Marine Sponges in U937 Human Leukemic Cells (인체 혈구암세포 U937에서 해양해면동물에서 추출된 Pectenotoxin-2에 의한 Apoptosis의 유발에 관한 연구)

  • Shin, Dong Yeok;Kang, Ho Sung;Bae, Song-Ja;Jung, Jee H.;Choi, Yung Hyun
    • Journal of Marine Bioscience and Biotechnology
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    • v.1 no.2
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    • pp.63-70
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    • 2006
  • Natural product compounds are the source of numerous therapeutic agents. The marine environment produces natural products from a variety of structural classes exhibiting activity against numerous disease targets including anticancer agents. Among these, pectenotoxin-2 (PTX-2), which was first identified as a cytotoxic entity in marine sponges, which depolymerizes actin filaments, was found to be highly effective and more potent to activate an intrinsic pathway of apoptosis in p53-deficient tumor cells compared to those with functional p53 both in vitro and in vivo. However, the anti-proliferative mechanism of the compound at non-cytotoxic concentrations has not yet been explored. In the current study, we sought to investigate anti-proliferation and apoptosis of PTX-2 against U937 human leukemic cells and its underlying molecular mechanism. Exposure of U937 cells to PTX-2 resulted in growth inhibition and induction of apoptosis in dose- and time-dependent manner as measured by MTT assay, fluorescent microscopy and flow cytometric analysis. The anti-proliferative effect of PTX-2 was associated with a marked increase in the expression of cyclin-dependent kinase p21 (WAF1/CIP1) mRNA which was tumor suppressor p53-independent. The increase in apoptosis was connected with a time-dependent down-regulation of anti-apoptotic Bcl-XL and inhibitor of apoptosis proteins (IAPs) family such as XIAP and cIAP-2. Though additional studies are needed, these findings suggested that PTX-2-induced inhibition of U937 cells was associated with the induction of apoptotic cell death and the results provided important new insights into the possible molecular mechanisms of the anti-cancer activity of PTX-2.

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Styrylpyrone Derivative Induces Apoptosis through the Up-Regulation of Bax in the Human Breast Cancer Cell Line MCF-7

  • Chien, Alvin Lee Teck;Pihie, Azimahtol Hawariah Lope
    • BMB Reports
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    • v.36 no.3
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    • pp.269-274
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    • 2003
  • In the fight against cancer, novel chemotherapeutic agents are constantly being sought to complement existing drugs. Various studies have presented evidence that the apoptosis that is induced by these anticancer agents is implicated in tumor regression, and Bcl-2 family genes play a part in apoptosis following treatment with various stimuli. Here, we present data that a styrylpyrone derivative (SPD) that is extracted from the plant Goniothalamus sp. showed cytotoxic effects on the human breast cancer cell line MCF-7. SPD significantly increased apoptosis in MCF-7 cells, as visualized by phase contrast microscopy and evaluated by the Tdt-mediated dUTP nick end-labeling assay and nuclear morphology. Western blotting and immunostaining revealed up-regulation of the proapoptotic Bax protein expression. SPD, however, did not affect the expression of the anti-apoptotic protein, Bcl-2. These results, therefore, suggest SPD as a potent cytotoxic agent on MCF-7 cells by inducing apoptosis through the modulation of Bax levels.

Ornithine Decarboxylase: A Promising and Exploratory Candidate Target for Natural Products in Cancer Chemoprevention

  • Luqman, Suaib
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.5
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    • pp.2425-2427
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    • 2012
  • Ornithine decarboxylase (ODC), the first enzyme in the polyamine biosynthesis, plays an important role in tumor progression, cell proliferation and differentiation. In recent years, ODC has been the subject of intense study among researchers, as a target for anti-cancer therapy and specific inhibitory agents, have the potential to suppress carcinogenesis and find applications in clinical therapy. In particular, it is suggested that ODC is a promising candidate target for natural products in cancer chemoprevention. Future exploration of ornithine decarboxyalse inhitors present in nature may offer great hope for finding new cancer chemporeventive agents.

Cyclic Peptides as Therapeutic Agents and Biochemical Tools

  • Joo, Sang-Hoon
    • Biomolecules & Therapeutics
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    • v.20 no.1
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    • pp.19-26
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    • 2012
  • There are many cyclic peptides with diverse biological activities, such as antibacterial activity, immunosuppressive activity, and anti-tumor activity, and so on. Encouraged by natural cyclic peptides with biological activity, efforts have been made to develop cyclic peptides with both genetic and synthetic methods. The genetic methods include phage display, intein-based cyclic peptides, and mRNA display. The synthetic methods involve individual synthesis, parallel synthesis, as well as split-and-pool synthesis. Recent development of cyclic peptide library based on split-and-pool synthesis allows on-bead screening, in-solution screening, and microarray screening of cyclic peptides for biological activity. Cyclic peptides will be useful as receptor agonist/antagonist, RNA binding molecule, enzyme inhibitor and so on, and more cyclic peptides will emerge as therapeutic agents and biochemical tools.

Studies on the Synthesis and Antitumor Actiities of Potential Antineoplastic Agents. IV. Synthesis and Antitumor Activities of N-Substituted-p-Arsanilic Acid (제암성물질의 합성및 항종양시험에 관한 연구 IV N-치환, p-Arsanilic Acid 유도체의 합성 및 항종양시험)

  • 정원근;천문우;김중협;이남복
    • YAKHAK HOEJI
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    • v.15 no.1
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    • pp.16-23
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    • 1971
  • Seven organic arsine compounds are synthesized as potential anti-tumor agents are subjected to the screening test of activity against SN-36 Leukemia, Sarcoma 180 and Ehrlich ascites carcinoma. Three compounds, namely N-(5-Nitrofroyl)-p-arsanilic acid, N-(2, 4-Dihydroxybenzoethyl)-p-arsanilic acid and N-$\alpha$(p-arsanilido) acetyl thiourea of the all synthesized compounds showed comparatively potential activities against experimental ascitic tumors both through cytological findings and survival duration.

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Study on the Antitumor Activity of Tripterygium Regelii Sprague (미역줄나무의 항암활성에 관한 연구)

  • Park, Wan-Su
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.19 no.2
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    • pp.441-445
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    • 2005
  • Tripterygium regelii has been used as an oriental medicine, especially antiparasitic, anti-inflammatory and detoxifying agents in East asia. During our research to develop new antitumor agents from natural products, MeOH ext. and CH2Cl2 ext. of Tripterygium regelii showed the potent antitumor activity. In order to purify active compounds from Tripterygium regelii, activity-guided fractionation was carried out. Silica gel and RP-18 column chromatography for the active fraction led to the isolation of two compounds and their antitumor activities were studied. Those two compounds didn't show potent antitumor activity against human tumor cell lines. The structure of two compounds were determined by $^1H-NMR$, $^{13}C-NMR$, DEPT, $^1H-^{13}C$ COSY and IR spectrum. Compound I and Compound II were turned out to be Celastrol, and ${\beta}-sitosteryl-3-o-{\beta}-D-glucopyranoside$ respectively.

Cytotoxic Effect of Urushiol-ethanol Micro-particles on Human Cervical Carcinoma Cells (우루시올-에탄올 수분산 미립자의 자궁경부암세포에 대한 독성효과)

  • Kim, Jin-Woo;Ryu, Kyu-Eun;Jang, Hong-Seok;Ahn, Woong-Shick;Choi, Jong-Oh;Chun, Heung-Jae
    • Journal of Pharmaceutical Investigation
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    • v.34 no.1
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    • pp.23-27
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    • 2004
  • The urushiol-ethanol corpuscle of 320 nM in average particle size was prepared and concentrated by ultra homogenization and centrifugation. The cytotoxic profiles of this particle for use as anti-tumor agent have been evaluated in vitro in cultures of human fibroblasts (MRC-9) and celvical carcinoma cells (CUMC-3). The cytotoxicty assays revealed that the inhibitor effect of $10^{-5}$ M urushiol-ethanol particle on the growth of MRC-9 was hardly detected, while CUMC-3 cells exhibited over 50% of growth inhibition under the same conditions. In addition, a clear multiple-unit ladder pater of apoptotic DNA was observed for the urushiol treated CUMC-3 cells. Thus, the results indicated that urushiol inhibited growth of celvical carcinoma cells by inducing apoptosis, which is a mechanism observed with other typical antitumor agents.

[6]-Gingerol Inhibits Phorbol Ester-Induce d Expression of Cyclooxygenase-2 in Mouse Skin: p38 MAPK and p65/RelA as Possible Molecular Targets

  • Kim, Sue-Ok;Chun, Kyung-Soo;Surh, Young-Joon
    • Proceedings of the Korean Society of Toxicology Conference
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    • 2003.05a
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    • pp.95.1-95
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    • 2003
  • Ginger (Zingiber officinale Roscoe, Zingiberaceae) has a wide array of pharmacologic effects. Our previous studies have demonstrated that [6]-gingerol, a major pungent ingredient of ginger, inhibits mouse skin tumor promotion and anchorage-independent growth of cultured mouse epidermal cells stimulated with epidermal growth factor. In this study, we have investigated the molecular mechanisms underlying chemopreventive effects of [6]-gingerol on mouse skin carcinogenesis. Cyclooxygenase-2 (COX-2), a key enzyme in the formation of prostaglandins, has been recognized as a molecular target of many chemopreventive as well as anti-inflammatory agents. The murine COX-2 promoter contains several transcriptional elements, particularly those involved in regulating inflammatory processes. One of the essential transcription factors responsible for COX-2 induction is NF-kappa B. Topical application of [6]-gingerol inhibited the COX-2 expression through suppression of NF-kappa B activation in phorbol ester-treated mouse skin. [6]-Gingerol, through down-regulation of p38 MAPK, abrogated the DNA binding activity of NF-kappa B by blocking phosphorylation of p65/RelA at the Ser 536 residue. These findings suggest that [6]-gingerol exerts an anti-tumor promotional activity through inhibition of the p38 MAPK-NF-kappa B siganling cascade in mouse skin.

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Sequence Analysis and Potential Action of Eukaryotic Type Protein Kinase from Streptomyces coelicolor A3(2)

  • Roy, Daisy R.;Chandra, Sathees B.C.
    • Genomics & Informatics
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    • v.6 no.1
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    • pp.44-49
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    • 2008
  • Protein kinase C (PKC) is a family of kinases involved in the transduction of cellular signals that promote lipid hydrolysis. PKC plays a pivotal role in mediating cellular responses to extracellular stimuli involved in proliferation, differentiation and apoptosis. Comparative analysis of the PKC-${\alpha},{\beta},{\varepsilon}$ isozymes of 200 recently sequenced microbial genomes was carried out using variety of bioinformatics tools. Diversity and evolution of PKC was determined by sequence alignment. The ser/thr protein kinases of Streptomyces coelicolor A3 (2), is the only bacteria to show sequence alignment score greater than 30% with all the three PKC isotypes in the sequence alignment. S.coelicolor is the subject of our interest because it is notable for the production of pharmaceutically useful compounds including anti-tumor agents, immunosupressants and over two-thirds of all natural antibiotics currently available. The comparative analysis of three human isotypes of PKC and Serine/threonine protein kinase of S.coelicolor was carried out and possible mechanism of action of PKC was derived. Our analysis indicates that Serine/ threonine protein kinase from S. coelicolor can be a good candidate for potent anti-tumor agent. The presence of three representative isotypes of the PKC super family in this organism helps us to understand the mechanism of PKC from evolutionary perspective.

Emerging Targets for Systemic Treatment of Gastric Cancer: HER2 and Beyond

  • In-Ho Kim
    • Journal of Gastric Cancer
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    • v.24 no.1
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    • pp.29-56
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    • 2024
  • In recent years, remarkable progress has been made in the molecular profiling of gastric cancer. This progress has led to the development of various molecular classifications to uncover subtype-specific dependencies that can be targeted for therapeutic interventions. Human epidermal growth factor receptor 2 (HER2) is a crucial biomarker for advanced gastric cancer. The recent promising results of novel approaches, including combination therapies or newer potent agents such as antibody-drug conjugates, have once again brought attention to anti-HER2 targeted treatments. In HER2-negative diseases, the combination of cytotoxic chemotherapy and programmed cell death-1/programmed cell death ligand-1 (PD-1/PD-L1) inhibitors has become the established standard of care in first-line settings. In the context of gastric cancer, potential biomarkers such as PD-L1 expression, Epstein-Barr virus, microsatellite instability, and tumor mutational burden are being considered for immunotherapy. Recently, promising results have been reported in studies on anti-Claudin18.2 and fibroblast growth factor receptor 2 treatments. Currently, many ongoing trials are aimed at identifying potential targets using novel approaches. Further investigations will be conducted to enhance the progress of these therapies, addressing challenges such as primary and acquired resistance, tumor heterogeneity, and clonal evolution. We believe that these efforts will improve patient prognoses. Herein, we discuss the current evidence of potential targets for systemic treatment, clinical considerations, and future perspectives.