• Asian Pacific Journal of Cancer Prevention
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• v.17 no.8
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• pp.3865-3869
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• 2016

Curcumin, a polyphenolic compound isolated from the rhizomes of an herbaceous perennial plant, Curcuma longa, is known to possess anticancerous activity. However, the mechanism of apoptosis induction in cancers differs. In this study, we have (1) investigated the anticancerous activity of curcumin on REH and RS4;11 leukemia cells and (2) studied the chemo-sensitizing potential of curcumin for doxorubicin, a drug presently used for leukemia treatment. It was found that curcumin induced a dose dependent decrease in cell viability because of apoptosis induction as visualized by annexin V-FITC/ PI staining. Curcumin-induced apoptosis of leukemia cells was mediated by PARP-1 cleavage. An increased level of caspase-3, apoptosis inducing factor (AIF), cleaved PARP-1 and decreased level of Bcl2 was observed in leukemia cells after 24h of curcumin treatment. In addition, curcumin at doses lower than the $IC_{50}$ value significantly enhanced doxorubicin induced cell death. Therefore, we conclude that curcumin induces apoptosis in leukemia cells via PARP-1 mediated caspase-3 dependent pathway and further may act as a potential chemo-sensitizing agent for doxorubicin. Our study highlights the chemo-preventive and chemo-sensitizing role of curcumin.

• The Journal of Pediatrics of Korean Medicine
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• v.22 no.1
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• pp.113-121
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• 2008

Objectives In human myeloid leukemia cells, there are no specific features of apoptosis compared with apoptosis in other cell types. Solanum nigrum L.(SNL) is a deciduous tree, which is widely distributed in Korea with reported anti-tumor, anti-inflammatory and non-specific immune-enhancing properties. Although the plant has been clinically used for treating a variety of diseases, its bioactive ingredients are unknown and its mode of action potential has never been investigated. Thus anti-tumor property of methanol extract was investigated. Methods In this study, anti-tumor property of methanol extract was investigated by determining its in vitro growth-inhibitory effects on human myeloid leukemia cells. XTT proliferation assay, DNA fragmentation, immunoblot analysis, densitometric analysis were used. Results 1. The methanol fraction of the extracts of SNL induced mitochondria-mediated apoptosis in human myeloid leukemia cells. 2. The methanol fraction exhibited relatively higher cytotoxic activity in a dose-dependent manner than chloroform, and hexane fraction. 3. Typical ladder profile of Oligonucleosomal fragments were appeared. 4. The secreted cytosolic cytochrome C level was increased by treatment of methanol fraction. Conclusions Methanol fraction of SNL is capable of inducing apoptosis in human myeloid leukemia cells.

• BMB Reports
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• v.45 no.2
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• pp.85-90
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• 2012

Our previous study demonstrated that CopA3, a disulfide dimer of the coprisin peptide analogue (LLCIALRKK), has antibacterial activity. In this study, we assessed whether CopA3 caused cellular toxicity in various mammalian cell lines. CopA3 selectively caused a marked decrease in cell viability in Jurkat T, U937, and AML-2 cells (human leukemia cells), but was not cytotoxic to Caki or Hela cells. Fragmentation of DNA, a marker of apoptosis, was also confirmed in the leukemia cell lines, but not in the other cells. CopA3-induced apoptosis in leukemia cells was mediated by apoptosis inducing factor (AIF), indicating induction of a caspase-independent signaling pathway.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.2
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• pp.629-635
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• 2014

Background: Acute myeloid leukemia (AML) is a fatal hematological malignancy which is resistant to a variety of chemotherapy drugs. Myeloid cell leukemia-1 (Mcl-1), a death-inhibiting protein that regulates apoptosis, has been shown to be overexpressed in numerous malignancies. In addition, it has been demonstrated that the expression level of the Mcl-1 gene increases at the time of leukemic relapse following chemotherapy. The aim of this study was to target Mcl-1 by small interference RNA (siRNA) and analyze its effects on survival and chemosensitivity of acute myeloid leukemia cell line HL-60. Materials and Methods: siRNA transfection was performed with a liposome approach. The expression levels of mRNA and protein were measured by real-time quantitative PCR and Western blot analysis, respectively. Trypan blue assays were performed to evaluate tumor cell growth after siRNA transfection. The cytotoxic effects of Mcl-1 siRNA (siMcl-1) and etoposide were determined using MTT assay on their own and in combination. Apoptosis was quantified using a DNA-histone ELISA assay. Results: Transfection with siMcl-1 significantly suppressed the expression of Mcl-1 mRNA and protein in a time-dependent manner, resulting in strong growth inhibition and spontaneous apoptosis. Surprisingly, pretreatment with siMcl-1 synergistically enhanced the cytotoxic effect of etoposide. Furthermore, Mcl-1 down-regulation significantly increased apoptosis sensitivity to etoposide. No significant biological effects were observed with negative control siRNA treatment. Conclusions: Our results suggest that specific suppression of Mcl-1 by siRNA can effectively induce apoptosis and overcome chemoresistance of leukemic cells. Therefore, siMcl-1 may be a potent adjuvant in leukemia chemotherapy.

• Journal of Physiology & Pathology in Korean Medicine
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• v.16 no.5
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• pp.932-937
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• 2002

The purpose of this research was to investigate the effect of Yonggak-san (YGS) on the immune reaction and apoptosis of leukemia cells. Administration of YGS(500 mg/kg) enhanced proliferation of splenocytes, thymocytes and mesenteric lymph node cells, and also YGS accelerated subpopulation of splenic Band T, thymic T and mesenteric lymph node-T lymphocytes, especially significantly increased CD4+-TH cells in BALB/c mice. YGS accelerated phagocytic activity and production of nitric oxide in peritoneal macrophages. YGS induced apoptosis of transplanted-L1210 cells in vivo, increased apoptotic cell death of cultured-L1210 and/or Molt4 human leukemia cells, decreased of mitochondrial transmembrane potential of both cells in vitro. These results suggest that YGS have an immune-regulatory effect and anti-cancer property.

• Journal of Microbiology and Biotechnology
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• v.19 no.9
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• pp.946-950
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• 2009

In the course of screening for apoptotic substances that induce apoptosis in human leukemia U937 cells, a fungal strain, F000487, which exhibits potent inducible activity, was selected. The active compound was purified from an ethyl acetate extract of the microorganism by Sep-pak $C_{18}$ column chromatography and HPLC, and was identified as atromentin by spectroscopic methods. This compound induced caspase-3 processing in human leukemia U937 cells. The caspase-3 and poly (ADP-ribose) polymerase (PARP) were induced by atromentin in a dose-dependent manner. Furthermore, DNA fragmentation was also induced by this compound in a dose-dependent manner. These results show that atromentin potently induces apoptosis in U937 cells and that atromentin-induced apoptosis is related to the selective activation of caspases.

• Journal of Physiology & Pathology in Korean Medicine
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• v.23 no.6
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• pp.1404-1408
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• 2009

Methanol extracts of Rubus Coreanus Miquel (RCM) were found to exhibit apoptosis induction of U937 human histiocytic leukemia cells. Treatment of RCM exerted strong cytotoxicity against U937 human leukemia cells. RCM induced apoptosis of U937 leukemia cells in a dose dependent manner. Nitric oxide (NO) production was increased in RCM-treated RAW264.7 macrophage cell line. RCM increased the p53 and $NF{\kappa}B$ gene and decreased the $I{\kappa}B$ gene expression in U937 cells. RCM also increased the $NF{\kappa}B$ protein expression, but decreased the PCNA and BcL-xL protein expression in cultured U937 cells. These data suggest that RCM are effective on the apoptosis induction of human leukemia cells and anti-cancer properties.

• BMB Reports
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• v.35 no.4
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• pp.377-383
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• 2002

Arsenic trioxide ($As_O_3$) was recently demonstrated to be an effective inducer of apoptosis in patients with relapsed acute promyelocytic leukemia (APL) as well as patients with APL in whom all-trans-retinoic acid and conventional chemotherapy failed. Chronic myelogenous leukemia cells are highly resistant to chemotherapeutic drugs. To determine if $As_O_3$ might be useful for the treatment of chronic myelogenous leukemia, we examined the ability of $As_O_3$ to induce apoptosis in K562 cells. In vitro cytotoxicity of $As_O_3$ was evaluated in K562 cells by a MTT assay: the $IC_50$ value for $As_O_3$ was determined to be $10\;{\mu}m$. When analyzed by agarose gel electorphoresis, the DNA fragments became evident after incubation of the cells with $20\;{\mu}m$ $As_O_3$ for 24 h. We also found morphological changes and chromatin condensation of the cells undergoing apoptosis. Activation of caspase-3 was observed 6 h after treatment with $20\;{\mu}m$ $As_O_3$ by a Western blot analysis. Next, we examined the MAP kinase-signaling pathway of $As_O_3$-induced apoptosis in K562 cells. $As_O_3$ at $10\;{\mu}m$ strongly induced the activation of p38, inhibited $As_O_3$ induced apoptotic cell death. These results suggest that $As_O_3$ is able to induce the apoptotic activity in K562 cells, and its apoptotic mechanism may be associated with the activation of p38.

• Biomolecules & Therapeutics
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• v.18 no.2
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• pp.178-183
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• 2010

Costunolide is an active compound isolated from the stem bark of Magnolia sieboldii, and is considered a potential therapeutic for the treatment of various cancers. In this study, we investigated the underlying mechanism whereby costunolide induces the apoptosis of human leukemia cells. Using apoptosis analysis and quantitative reverse transcription-polymerase chain reaction (RT-PCR) results obtained during this study show that costunolide is a potent inducer of apoptosis and that it is triggered due to the premature activation of Cdc2. $G_1$-synchronized cells, which cannot undergo mitosis, were found to be more sensitive to costunolide, and Cdc2 mRNA levels were increased by costunolide treatment. Furthermore, the Cdk inhibitors, olomucine and butyrolactone I, were found to suppress costunolide-induced apoptosis. In addition, the PKC activator TPA rescued cells from cell death by costunolide, and this was prevented by the PKC inhibitor staurosporin. The present study suggests that costunolide induces the apoptosis of HL-60 leukemic cells by modulating cyclin-dependent kinase Cdc2.

• Food Science and Biotechnology
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• v.17 no.6
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• pp.1305-1309
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• 2008

Baicalein, one of the major flavonoid in Scutellaria baicalensis, has been known for its effects on proliferation and apoptosis of many tumor cell lines. Most biological effects of baicalein are thought to be from its antioxidant and prooxidant activities. In this report, baicalein was found to induce apoptosis in HL60 human promyelocytic leukemia cell line. Baicalein treatment induced DNA fragmentation and typical morphological features of apoptosis. To elucidate the mechanism of baicalein-induced apoptosis, the activities of the members of caspase family were measured. Interestingly caspase 2, 3, and 6 were significantly activated whereas caspase 1, 8, and 9 were not activated, suggesting selective involvement of specific caspases. Further, treatment with caspase inhibitors also supports the involvement of caspase 2 in apoptosis process. Although it has been reported that baicalein can induce apoptosis through many caspase pathways, the present study indicates that caspase 2 not caspase 9 pathway may be the important step in apoptosis on HL60 cell line.