• YAKHAK HOEJI
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• v.48 no.2
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• pp.153-158
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• 2004

Paecilomyces tenuipes is one of the famous Chinese medicinal entomopathogenic fungi that parasite in the lavae of silkworm. A cytotoxic compound, 4$\beta$-acetoxyscirpendiol (ASD) was isolated from a methanolic extracts of Paecilomyces tenuipes. The ASD compound belongs to scirpenol subfamily of trichothecene mycotoxin. In a continuation of the elucidation of the mechanism of ASD, we report here the evidences of induction of apoptosis by ASD in human Jurkat T cell line. In MTT reduction assay for monitoring cell viability, ASD showed strong toxicity. The 50 percent inhibitory concentrations of ASD against human T lymphoid Jurkat cell was 59.5 ng/$m\ell$. Phosphatidylserine externalization was increased by ASD at 3 and 6 hrs when compared with that of 6 hrs in the cell line showing in a time-dependent manner. When whole lysates of cells treated with ASD were subjected to western blot assay, 113 kDa poly(ADP-ribose) polymerase (PARP) was significantly cleaved to 89 kDa fragment. Time-dependent DNA fragmentation was also observed when Jurkat T cells were treated with ASD at 100 ng/$m\ell$ for 6 hrs and 18 hrs at the ratios of 8.5% and 15.0%, respectively. From these data, Jurkat T lymphocytes treated with ASD from Paecilomyces tenuipes underwent typical cascades of apoptotic cell death.

• Biomolecules & Therapeutics
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• v.17 no.1
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• pp.86-91
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• 2009

In our ongoing search for biological components from the Korea endemic plants, the MeOH extract of Ailanthus altissima leaves (Simaroubaceae) showed cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX) dual inhibitory activity by assessing their effects on the production of prostaglandin $D_2$ ($PGD_2$) and leukotriene $C_4$ ($LTC_4$) in mouse bone marrow-derived mast cells (BMMCs). In further study, eight compounds, squalene (1), ${\beta}$-sitosterol (2), scopoletin (3), quercetin (4), luteolin (5), astragalin (6), scopolin (7), and daucosterol (8) were isolated, the chemical structures were elucidated on the basis of physicochemical and spectroscopic data and by comparison with those of published literatures. Among the compounds, 2, 4, and 5 strongly inhibited both the COX-2-dependent PGD2 generation with $IC_{50}$ values of 2.6, 7.3 and 2.5 ${\mu}M$, respectively and the generation of $LTC_4$ in the 5-LOX dependent phase with $IC_{50}$ values of 2.0, 5.1 and 1.8 ${\mu}M$, respectively, which suggest that the anti-inflammatory activity of A. altissima might occur in part via the inhibition of both $PGD_2$ and $LTC_4$ generation by 2, 4 and 5.

• Archives of Pharmacal Research
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• v.19 no.6
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• pp.490-496
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• 1996

Naphtodianthrone hypericin produced a potent antitumor activity in vitro against several tumor cells. However, it did not show any cytotoxicity on normal cells such as Macaccus rheus monkey kidney cells (MA-104) and primary cultured rat hepatocytes up to $500{\mu}M$ concentration. Hypericin added to A431 human epidermoid carcinoma cell membrane inhibited the autophosphorylation of the epidermal growth factor (EGF) receptor and the tyrosine phosphorylation of RR-SRC peptide catalyzed by an EGF-receptor. Similarly, treatment of the A431 cells with hypericin inhibited the tyrosine phosphorylation of EGF-dependent endogenous EGF-receptor by western blotting analysis. Hypericin also inhibited the T cell PTK, $P56^{lck}$, in a dose-dependent fashion with an $IC_{50}=5{\mu}M$. The tyrosine phosphorylation, on RR-SRC peptide and EGF-induced receptor autophosphorylation, either in vitro or in intact cells was inhibited by hypericin at the same concentration as that in A431 cell proliferation. These data suggest that hypericin directly inhibits EGF-receptor and $P56^{lck}$ PTK activity in vitro and can mediate such action in vivo.

• Biomedical Science Letters
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• v.29 no.1
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• pp.26-33
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• 2023

Ziziphus jujuba Mill. (ZJM), a traditional folk medicine and functional food in South Korea and China, has been reported to having pharmacological activities against anti-cancer, anti-oxidative, and anti-obesity. However, the effect of ZJM related to myoblast differentiation has not been known. In this study, we investigated the effects and mechanism of ZJM on myogenic differentiation of C2C12 cells. ZJM promotes myogenic differentiation and elevates the formation of multinucleated myotube compared to the control group. ZJM significantly increased the mRNA and protein expression of MyHC1, myogenin and MyoD in dose- and time-dependent manner. Interestingly, ZJM significantly inhibited the mRNA and protein expression of protein degradation markers, atrogin-1 and MuRF-1, in dose- and time-dependent manner. Taken together, our data suggest that ZJM is a potential functional candidate for muscle growth and strength by promoting myogenic differentiation.

• Journal of the Korean Society of Tobacco Science
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• v.26 no.2 s.52
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• pp.152-158
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• 2004

Among short-term in vitro genotoxicity assays, micronucleus assays are rapid, inexpensive, and less labor-intensive system. We have undertaken a comparative study of sensitivity of cigarette smoke condensate(CSC) by general micronucleus(MN) assay and cytokinesis-block micronucleus(CBMN) assay. In this study, V79 Chinese hamster cells were employed to evaluate and compare the genotoxicity of CSC of Kentucky Reference Cigarette 2R4F by 2 kinds of in vitro MN assay methods. To determine the optimum concentration of cytochalasin B(CYB) to obtain the maximal number of binucleated cells for CBMN assay, triplicate cultures of growing cells were treated with CYB for 15 h. CYB treatments caused a concentration-dependent increase in cytotoxicity($1\~4{\mu}g/mL$) and proportion($0.25\~1\;{\mu}g/mL$) of binucleated cells. These data suggested that 1 ug/mL of CYB is as an optimum dose for CBMN assay in binucleated V79 cells. Short treatment(4 h) of CSC induced a micronucleated cells with a concentration-dependent response in the presence or absence of CYB, but CSC-induced MNs were weakened when S9 was present. Long treatments(19 h) of CSC also induced a significant increase MN formation with a concentration-dependent response. At a concentration of 75 ${mu}g/mL$, the MN cell frequencies of general MN assay and CBMN assay were $6.5\%\;and\;11.7\%$, respectively. Linear regression analysis revealed a good correlation in CBMN assay between a concentration of CSC and MN cell frequency. All these data indicated that CBMN assay is more sensitive to the induction CSC-induced MN than general MN assay.

• BMB Reports
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• v.52 no.3
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• pp.208-213
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• 2019

Chemoresistance is the primary obstacle in the treatment of locally advanced and metastatic nasopharyngeal carcinoma (NPC). Recent evidence suggests that the transcription factor forkhead box M1 (FoxM1) is involved in chemoresistance. Our group previously confirmed that FoxM1 is overexpressed in NPC. In this study, we investigated the role of FoxM1 in cisplatin resistance of the cell lines 5-8F and HONE-1 and explored its possible mechanism. Our results showed that FoxM1 and NBS1 were both overexpressed in NPC tissues based on data from the GSE cohort (GSE12452). Then, we measured FoxM1 levels in NPC cells and found FoxM1 was overexpressed in NPC cell lines and could be stimulated by cisplatin. MTT and clonogenic assays, flow cytometry, ${\gamma}H2AX$ immunofluorescence, qRT-PCR, and western blotting revealed that downregulation of FoxM1 sensitized NPC cells to cisplatin and reduced the repair of cisplatin-induced DNA double-strand breaks via inhibition of the MRN (MRE11-RAD50-NBS1)-ATM axis, which might be related to the ability of FoxM1 to regulate NBS1. Subsequently, we demonstrated that enhanced sensitivity of FoxM1 knockdown cells could be reduced by overexpression of NBS1. Taken together, our data demonstrate that downregulation of FoxM1 could improve the sensitivity of NPC cells to cisplatin through inhibition of MRN-ATM-mediated DNA repair, which could be related to FoxM1-dependent regulation of NBS1.

• Toxicological Research
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• v.17 no.2
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• pp.131-137
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• 2001

Baicalein, a major flavonoid of extract from Scutellaria baicalensis Georgi, has been shown to exhibit antioxidant and anti proliferative effects. In the present study, we investigate the effects of baicalein on viability and induction of apoptosis in human promyelocytic leukemia HL-60 cells. Baicalein was found to induce apoptosis of HL-60 cells in a concentration-dependent and time-dependent manner. When HL-60 cells were exposed to 100 $\mu\textrm{M}$ baicalein for 6h, the viability was decreased remarkably to 27% of control, whereas DNA fragmentation was significantly increased to 64%. Nucleosomal fragmentation of baicalein treated HL-60 cells, a hallmark of apoptosis, was further identified by agarose gel electrophoresis (DNA ladder). Flow cytometric analysis showed that apoptotic cells were increased to 66.6% after treatment with 100 $\mu\textrm{M}$ baicalein for 6 h. Baicalein-induced apoptosis of HL-60 cells was reduced by 1h pretreatment with inhibitor of caspases, z-Asp-$CH_2$-DCB. At 3 and 10 $\mu\textrm{M}$ of z-Asp-$CH_2$-DCB, DNA fragmentation of HL-60 cells induced by baicalein (50 $\mu\textrm{M}$) was 36.8 and 17.1 %, respectively, whereas, that of HL-60 cells treated by baicalein (50 $\mu\textrm{M}$) without pretreatment with inhibitor of caspases was 62.7%. These data suggest that baicalein induces apoptosis in human leukemia HL-60 cells, and that caspase enzymes might be involved in baicalein-induced apoptosis.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.7
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• pp.3185-3189
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• 2014

Background: Breast cancer evolution and tumor progression are controlled by complex interactions between steroid receptors and growth factor receptor signaling. Aberrant growth factor receptor signaling can augment or suppress estrogen receptor function in hormone-dependent breast cancer cells. Thus, we aimed to investigate antitumor effects of sorafenib and lapatinib alone and in combination on MCF-7 breast cancer cells. Materials and Methods: Cytotoxicity of the sorafenib and lapatinib was tested in MCF-7 cells by XTT assays. 50, 25, 12.5 and $6.25{\mu}M$ concentrations of sorafenib and 200, 100, 50 and $25{\mu}M$ concentrations of lapatinib were administered alone and in combination. Results were evaluated as absorbance at 450nM and $IC_{50}$ values are calculated according to the absorbance data Results: Both sorafenib and lapatinib showed concentration dependent cytotoxic effects on MCF-7 cells. Sorafenib exerted cytotoxic effects with an $IC_{50}$ value of $32.0{\mu}M$; in contrast with lapatinib the $IC_{50}$ was $136.6{\mu}M$. When sorafenib and lapatinib combined, lapatinib increased cytotoxic effects of sorafenib at its ineffective concentrations. Also at the concentrations where both drugs had cytotoxic effects, combination show strong anticancer effects and killed approximately 70 percent of breast cancer cells. Conclusions: Combinations of tyrosine kinase inhibitors and cytotoxic agents or molecular targeted therapy has been successful for many types of cancer. The present study shows that both sorafenib and lapatinib alone are effective in the treatment of breast cancer. Also a combination of these two agents may be a promising therapeutic option in treatment of breast cancer.

• BMB Reports
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• v.49 no.1
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• pp.63-68
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• 2016

The serine/threonine kinase mTOR is essential for the phosphoinositide 3-kinases (PI3K) signaling pathway, and regulates the development and function of immune cells. Aberrant activation of mTOR signaling pathway is associated with many cancers including leukemia. Here, we report the contributions of mTOR signaling to growth of human leukemic cell lines and mouse T-cell acute leukemia (T-ALL) cells. Torin, an ATP-competitive mTOR inhibitor, was found to have both cytotoxic and cytostatic effects on U-937, THP-1, and RPMI-8226 cells, but not on Jurkat or K-562 cells. All cells were relatively resistant to rapamycin even with suppressed activity of mTOR complex 1. Growth of T-ALL cells induced by Notch1 was profoundly affected by torin partially due to increased expression of Bcl2l11 and Bbc3. Of note, activation of Akt or knockdown of FoxO1 mitigated the effect of mTOR inhibition on T-ALL cells. Our data provide insight on the effect of mTOR inhibitors on the survival and proliferation of leukemic cells, thus further improving our understanding on cell-context-dependent impacts of mTOR signaling. [BMB Reports 2016; 49(1): 63-68]

• Communications for Statistical Applications and Methods
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• v.23 no.5
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• pp.385-397
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• 2016

The stress-strength models have been intensively investigated in the literature in regards of estimating the reliability ${\theta}$ = P(X > Y) using parametric and nonparametric approaches under different sampling schemes when X and Y are independent random variables. In this paper, we consider the problem of estimating ${\theta}$ when (X, Y) are dependent random variables with a bivariate underlying distribution. The empirical and kernel estimates of ${\theta}$ = P(X > Y), based on bivariate ranked set sampling (BVRSS) are considered, when (X, Y) are paired dependent continuous random variables. The estimators obtained are compared to their counterpart, bivariate simple random sampling (BVSRS), via the bias and mean square error (MSE). We demonstrate that the suggested estimators based on BVRSS are more efficient than those based on BVSRS. A simulation study is conducted to gain insight into the performance of the proposed estimators. A real data example is provided to illustrate the process.