• Journal of Microbiology and Biotechnology
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• v.26 no.2
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• pp.287-294
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• 2016

The effect of kaempferol (3,5,7,4-tetrahydroxyflavone), a flavonoid compound that was identified in barnyard millet (Echinochloa crus-galli var. frumentacea) grains, on G₂-checkpoint and apoptotic pathways was investigated in human acute leukemia Jurkat T cell clones stably transfected with an empty vector (J/Neo) or a Bcl-xL expression vector (J/Bcl-xL). Exposure of J/Neo cells to kaempeferol caused cytotoxicity and activation of the ATM/ATR-Chk1/Chk2 pathway, activating the phosphorylation of p53 (Ser-15), inhibitory phosphorylation of Cdc25C (Ser-216), and inactivation of cyclin-dependent kinase 1 (Cdk1), with resultant G₂-arrest of the cell cycle. Under these conditions, apoptotic events, including upregulation of Bak and PUMA levels, Bak activation, mitochondrial membrane potential (Δψm) loss, activation of caspase-9, -8, and -3, anti-poly (ADP-ribose) polymerase (PARP) cleavage, and accumulation of apoptotic sub-G₁ cells, were induced without accompanying necrosis. However, these apoptotic events, except for upregulation of Bak and PUMA levels, were completely abrogated in J/Bcl-xL cells overexpressing Bcl-xL, suggesting that the G₂-arrest and the Bcl-xL-sensitive mitochondrial apoptotic events were induced, in parallel, as downstream events of the DNA-damage-mediated G₂-checkpoint activation. Together these results demonstrate that kaempferol-mediated antitumor activity toward Jurkat T cells was attributable to G₂-checkpoint activation, which caused not only G₂-arrest of the cell cycle but also activating phosphorylation of p53 (Ser-15) and subsequent induction of mitochondria-dependent apoptotic events, including Bak and PUMA upregulation, Bak activation, Δψm loss, and caspase cascade activation.

• Journal of Physiology & Pathology in Korean Medicine
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• v.21 no.4
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• pp.973-981
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• 2007

In the present study, we investigated the antiproliferative activity of the water extract of Samgibopae-tang (SGBPT) in NCI-H460 and A549 non-small-cell lung cancer cell lines. We found that exposure of A549 cells to SGBPT resulted in the growth inhibition in a dose-dependent manner as measured by MTT assay, however SGBPT did not affect the growth of NCI-H460 cells. The antiproliferative effect by SGBPT treatment in A549 cells was associated with morphological changes such as membrane shrinking and cell rounding up. SGBPT treatment did not induce the cell cycle arrest in both cell lines, however the frequency of sub-G1 population was concentration-dependently increased by SGBPT treatment in A549 cells. SGBPT treatment partially induced the expression of tumor suppressor p53 in A549 cells and the expression of cyclin-dependent kinase inhibitor p21(WAF1/CIP1) was markedly increased in both transcriptional and translational levels in A549 cells. The up-regulation of p21 by SGBPT occurred in a similar a concentration dependent manner to that observed with the inhibition of cell viability and induction of sub-G1 population of the cell cycle. However SGBPT treatment did not affect other growth regulation-related genes such as early growth response-1 (Egr-1), nonsteroidal anti-inflammatory drug-activated gene-1 (NAG-1), inducible nitric oxide synthease (iNOS), cyclooxygenases (COXs), telomere-regulatory factors in A549 as well as NCI-H460 cells. Taken together, these findings suggested that SGBPT-induced inhibition of human lung carcinoma A549 cell growth was aoosciated with the induction of p21 and the results provided important new insights into the possible molecular mechanisms of the anti-cancer activity of SGBPT.

• 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.

• Journal of Life Science
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• v.21 no.10
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• pp.1494-1499
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• 2011

${\beta}$-lapachone, a quinone of lapachol extracted from the bark of the lapacho tree, has been found to induce apoptosis in various human cancer cells. In the present study, we investigated further possible mechanisms by which ${\beta}$-lapachone exerts its pro-apoptotic action in cultured human lung cancer A549 cells. ${\beta}$-lapachone treatment resulted in inhibition of growth and induction of apoptosis in a concentration-dependent manner, as determined by MTT assay and flow cytometry analysis. The induction of apoptosis by ${\beta}$-lapachone was associated with up-regulation of the expression of p53 and p21 in both transcriptional and translational levels, and the phosphorylation of p53. In addition, ${\beta}$-lapachone activated caspase-3 and -9, and induced degradation of caspase-3 target proteins such as poly (ADP-ribose) polymerase (PARP) and ${\beta}$-catenin. Furthermore, ${\beta}$-lapachone treatment caused a progressive decrease in the expression levels of cyclooxygenase (COX)-2 without significant changes in the levels of COX-1, which was correlated with a decrease in prostaglandin E2 synthesis. Taken together, these results indicated that ${\beta}$-lapachone may have therapeutic potential in human lung cancer treatment.

• Journal of Physiology & Pathology in Korean Medicine
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• v.21 no.5
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• pp.1226-1232
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• 2007

Phellinus linteus is a well-known Oriental medicinal fungus that has various biological activities, including immunomodulatory and anti-tumor activities, the mechanisms of which are poorly understood. In the present study, we investigated the anti-proliferative activity of the methanol extract of P. linteus-Barley corn (MEPLB) in human lekemic U937 cells. It was found that exposure of U937 cells to MEPLB resulted morphological change and growth inhibition in a dose-dependent manner as measured by trypan blue count and MTT assay. Upon treatment with MEPLB, U937 cells developed many of the hallmark features of apoptosis, including condensation of chromatin and an increase in the sub-G1 population suggesting that the anti-proliferative effect of MEPLB is associated with the induction of apoptosis. The anti-proliferative and apoptotic effects of MEPLB were connected with a marked induction of the pro-apoptotic Bax and cyclin-dependent kinase (Cdk) inhibitor p21 in a p53-independent manner. Additionally, MEPLB treatment significantly induced the caspase-3 activity in U937 cells. Taken together, the present results suggest that apoptotic signals evoked by MEPLB in human leukemic U937 cells may converge caspase-3 activation through an up-regulation of Bax rather than a down-regulation of Bcl-2 or Bel-xL.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.1
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• pp.1-6
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• 2004

$\beta$-Sitosterol is the major phytosterol in higher plants, including fruits and vegetables. The molecule has been shown to have the potential for prevention and therapy for human cancer. We investigated the effects of $\beta$-sitosterol on the cell proliferation of HCT116 human colon cancer cells in order to understand its anti-proliferative mechanism. $\beta$-Sitosterol treatment resulted in the inhibition of cell proliferation in a concentration-dependent manner. The anti-proliferative effect of HCT116 cells by $\beta$-sitosterol was associated with formation of apoptotic bodies and degradation of $\beta$-catenin protein. In addition, $\beta$-sitosterol-treatment induced a marked accumulation of tumor suppressor p53 and a concomitant induction of cyclin-dependent kinase (Cdk) inhibitor p21 without alteration in the levels of cyclins and Cdks. Taken together, these findings provide important new insights into the possible molecular mechanisms of the anti-cancer activity of $\beta$-sitosterol.

• The Journal of Internal Korean Medicine
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• v.29 no.1
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• pp.130-148
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• 2008

Objective : This study was designed to investigate the effect of the water extract of Gamisamgibopae-tang(GMSGBPT), an oriental herbal formulation, on the growth of NCI-H460 and A549 human non-small-cell lung cancer cell lines. Methods : Cytotoxicity and cell morphology were evaluated by MTT assay and inverted microscope, respectively. Apoptosis was detected using agarose gel electrophoresis and flow cytometer. The expression levels of mRNAs and proteins of target genes were determined by RT-PCR and western blot analyses, respectively Result and Conclusion : We found that exposure of A549 cells to GMSGBPT resulted in the growth inhibition in a dose-dependent manner as measured by MTT assay, but GMSGBPTdid not affect the growth of NCI-H460 cells. The anti-proliferative effect of GMSGBPT treatment in A549 cells was associated with morphological changes, formation of apoptotic bodies and DNA fragmentation, and flow cytometry analysis confirmed that GMSGBPT treatment increased the populations of apoptotic-sub G1 phase. Growth inhibition and apoptotic cell death by GMSGBPT were connected with a up-regulation of cyclin-dependent kinase inhibitor p21 (WAF1/CIP1) mRNA and protein in a tumor suppressor p53-independent fashion. However GMSGBPT treatment did not affect other growth regulation-related genes such as early growth response-1 (Egr-1), nonsteroidal anti-inflammatory drug (NSAID)-activated gene-1 (NAG-1), inducible nitric oxide synthase (iNOS), cyclooxygenases (COXs), telomere-regulatory factors in A549 orNCI-H460 cells. Taken together, these findings partially provide novel insights into the possible molecular mechanism of the anti-cancer activity of GMSGBPT.

• Journal of Life Science
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• v.18 no.6
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• pp.804-813
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• 2008

Cordyceps militaris, the Chinese medicinal fungal genus Cordyceps, is reported to possess many pharmacological activities including immunological stimulating, anti-cancer, anti-virus and anti-infection activities. However, the molecular mechanisms of C. militaris on biochemical actions in cancer have not been clearly elucidated yet. In the present study, we investigated the anti-proliferative activity of the water extract of C. militaris (WECM) in human hepatocellular carcinoma HepG2 cells. It was found that WECM could inhibit the cell growth in a dose-dependent manner, which was associated with morphological changes and apoptotic cell death such as formation of apoptotic bodies and increased populations of apoptotic sub-G1 phase. Apoptotic cell death of HepG2 cells by WECM was connected with a up-regulation of pro-apoptotic Bax expression, tumor suppressor p53 and cyclin-dependent kinase inhibitor p21 (WAF1/CIP1). In addition, WECM treatment induced the proteolytic activation of caspase-3 and a concomitant degradation and/or inhibition of poly (ADP-ribose) polymerase (PARP), ${\beta}-catenin$ and phospholipase $(PLC)-{\gamma}1$ protein. Furthermore, caspase-3 inhibitor, z-DEVD-fmk, significantly inhibited WECM-induced apoptosis demonstrating the important role of caspase-3 in the observed cytotoxic effect. Taken together, these findings provide important new insights into the possible molecular mechanisms of the anti-cancer activity of C. militaris.

• Journal of Life Science
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• v.25 no.4
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• pp.441-449
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• 2015

Endlicheria anomala, a neotropical plant, is found in northern South America and the Amazon region. It is traditionally used to remove poisons and cure gangrene. According to recent data, this plant has diverse biological properties such as anti-oxidative, anti-inflammatory and anti-melanogenic properties. However, the anti-cancer effect of E. anomala and its molecular mechanisms remain unclear. In this study, we examined the anti-cancer effect and the active mechanism of methanol extract of E. anomala (MEEA) in human lung adenocarcinoma cells (A549) and human liver cancer cells (HepG2). Our data revealed that MEEA showed cytotoxic activity in a dose-dependent manner and induced apoptosis both in A549 and HepG2 cells. We verified evidences of apoptosis via formation of chromatin condensation, apoptotic body and accumulation of cells in the subG1 phase. Following observed apoptosis-related phenomena, we found that the induction of apoptosis by MEEA was associated with the increase of tumor suppressor p53 and cyclin-dependent kinase inhibitor p21 (WAF1/CIP1) expression. Furthermore, MEEA-induced apoptosis was characterized with proteolytic activation of caspase-3, degradation of poly ADP ribose polymerase (PARP), and up-regulation of pro-apoptotic Bax expression. Taken together, these findings indicate that MEEA may have potential cancer therapeutic utility in A549 and HepG2 cells.

• Journal of Marine Bioscience and Biotechnology
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• v.1 no.2
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• pp.76-83
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• 2006

Epidemiological studies have indicated that the ubiquitous consumption of seaweeds is a protective factor against some types of cancer. Previous results showed that the administration of seaweed powder or extract reduced the incidence rate of chemically induced tumorigenesis using in vivo animal model. Recently, we reported that the extracts of Gloiopeltis furcata, a kind of Korean edible seaweed, caused he cell growth inhibition of various human cancer cell lines, among them methanol extract exhibited a relatively strong antiproliferative activity. However, the molecular mechanisms of this seaweed in malignant cells have been poorly studied until now. To elucidate this problem, we investigated the effects of methanol extract of G. furcata (MEGF) on the growth inhibition in several human cancer cell lines, and further we analyzed the effects of this extract were tested on the activity of apoptosis induction in human leukemic cells. The results demonstrated that MEGF treatment resulted in the morphological changes and the growth inhibition in a dose-dependent manner. Furthermore, MEGF potently suppresses the growth of human leukemic U937 cells by induction of apoptosis, which was associated with induction of cyclin-dependent kinase inhibitor p21(WAF1/CIP1) in a tumor suppressor p53-independent fashion and up-regulation of Fas/FasL system. Further studies will be needed to identify the active compounds that confer the anticancer activity of MEGF. Once such compounds are identified, the mechanisms by which they exert their effects can begin to be characterized.