Jong Soon Choi

Mountain ginseng extract exhibits anti-lung cancer activity by inhibiting the nuclear translocation of NF-κB

Administration of mountain ginseng (MG) extract can restore advanced cancer to a normal state. To elucidate the mechanism by which MG extract prevents the progression of lung cancer, the processes of proliferation and death of lung cancer cells (A549) were examined after treatment with MG extract. Butanol-extracted MG (BX-MG) showed a high inhibitory effect (IC(50) = 2 mg/ml) by attenuating proliferation and inducing apoptosis in lung cancer cells. By HPLC-UV analysis of BX-MG, ginsenosides, Rb1 was identified as the most abundant ginsenoside, followed by Rg1, Re, Rc and Rb2. BX-MG induced caspase-3 dependent apoptosis by inhibiting NF-κB. In addition, BX-MG activated p53 and p21, resulting in the attenuated proliferation of A549 cells. Reduced activity of the NF-κB promoter and increased activity of the p53 promoter indicate that BX-MG regulates apoptosis at the level of transcription in lung cancer cells. Furthermore, BX-MG blocked the nuclear translocation of RelA and the associated reduction in surviving. These results suggest that BX-MG inhibits lung cancer cell growth by activating tumor suppressors and inhibiting nuclear translocation of NF-κB.

Lactobacillus casei Extract Induces Apoptosis in Gastric Cancer by Inhibiting NF-κB and mTOR-Mediated Signaling

Lactobacillus casei extract (LBX) has been reported to prevent gastric cancer, but the underlying mechanism remains unclear. The proliferation and cell death of gastric cancer KATO3 cells were examined after treatment with LBX for various times and at various doses. LBX inhibited the growth of gastric cancer cells and induced apoptosis by inactivating NF-κB promoter activity. Apoptosis induced by LBX, however, is not directly associated with the intrinsic mitochondrial pathway. Immunoblot analysis revealed that LBX decreased the expressions of NF-κB and IκB. The reduced NF-κB levels led to the decreased phosphorylation of mTOR signaling components, such as PI3K, Akt, and p70S6 kinase. These results showed for the first time that LBX induced apoptosis in gastric cancer cells by inhibiting NF-κB and mTOR-mediated signaling.

Differential Expression of Extracellular Matrix Proteins in Senescent and Young Human Fibroblasts: a Comparative Proteomics and Microarray Study

The extracellular matrix (ECM) provides an essential structural framework for cell attachment, proliferation, and differentiation, and undergoes progressive changes during senescence. To investigate changes in protein expression in the extracellular matrix between young and senescent fibroblasts, we compared proteomic data (LTQ-FT) with cDNA microarray results. The peptide counts from the proteomics analysis were used to evaluate the level of ECM protein expression by young cells and senescent cells, and ECM protein expression data were compared with the microarray data. After completing the comparative analysis, we grouped the genes into four categories. Class I included genes with increased expression levels in both analyses, while class IV contained genes with reduced expression in both analyses. Class II and Class III contained genes with an inconsistent expression pattern. Finally, we validated the comparative analysis results by examining the expression level of the specific gene from each category using Western blot analysis and semiquantitative RT-PCR. Our results demonstrate that comparative analysis can be used to identify differentially expressed genes.

An enzymatically fortified ginseng extract inhibits proliferation and induces apoptosis of KATO3 human gastric cancer cells via modulation of Bax, mTOR, PKB and IκBα

Accumulative evidence suggests ginseng extract and/or its major components, ginsenosides and compound K, a metabolized ginseng saponin, have anti-cancer effects. In the present study, the effects of a ginseng butanolic extract (GBX) and an enzymatically fortified ginseng extract (FGX), with enriched ginsenosides and compound K, on the growth of KATO3 human gastric cancer cells were investigated using a cell viability assay. While treatment with GBX at 31.25-125 mg/ml for 24 h did not affect the proliferation of KATO3 cells, FGX under the same conditions inhibited cell proliferation in a concentration-dependent manner. Furthermore, Annexin V/PI-staining and flow cytometric analysis demonstrated that the population of apoptotic KATO3 cells was increased following treatment with FGX, which was greater than in the GBX-treated cells, suggesting that FGX had a stronger apoptotic effect than GBX. To investigate the underlying mechanism of the cytostatic and cytotoxic effects of the ginseng extracts, apoptosis-associated proteins were assessed using western blot analysis. The data revealed higher expression levels of B-cell lymphoma 2-associated X protein (Bax), lower expression of nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor α (IκBα) and reduced phosphorylation of mammalian target of rapamycin (mTOR) and protein kinase B (PKB) in the FGX-treated KATO3 cells than in the GBX-treated cells. Collectively, these results demonstrated for the first time, to the best of our knowledge, that FGX had stronger anti-proliferative and pro-apoptotic effects on KATO3 cells than GBX. The anti-proliferative and/or pro-apoptotic effects of FGX appeared to be mediated via the upregulation of Bax, IκBα proteolysis (activation of nuclear factor-κB) and the blocking of mTOR and PKB signals.

Development of Lectin-Linked Immunomagnetic Separation for the Detection of Hepatitis A Virus

The accuracy and sensitivity of PCR-based methods for detection of hepatitis A virus (HAV) are dependent on the methods used to separate and concentrate the HAV from the infected cells. The pH and ionic strength affect the binding affinity of the virus to cells. In this study, we initially investigated the effects of pH (4.0–10.0) and metal ions (Fe2+, Co2+, Cu2+, Mg2+, K+, and Ca2+) on the binding of HAV to oyster digestive cells. The lowest relative binding (RB) of HAV to the cells was found at pH 4.0 and in FeSO4 solution (64.6% and 68.1%, respectively). To develop an alternative to antibody-dependent immunomagnetic separation prior to detection of HAV using RT-PCR, the binding of HAV to five lectins, peanut agglutinin (PNA), Dolichos biflorus agglutinin (DBA), Helix pomatia agglutinin (HPA), Ulex europaeus agglutinin (UEA-1) and soybean agglutinin (SBA), was evaluated using ELISAs. SBA showed significantly higher RB to HAV than the other lectins tested. In addition, HAV could be concentrated within 30 min using SBA-linked magnetic bead separation (SMS) prior to the RT-PCR assay. Our findings demonstrate the feasibility of using SMS combined with RT-PCR to detect HAV at dilutions ranging from 10−1–10−4 of a HAV stock (titer: 104 TCID50/mL).

Tetraspanin-2 promotes glucotoxic apoptosis by regulating the JNK/β-catenin signaling pathway in human pancreatic β cells

Diabetes mellitus is a complex and heterogeneous disease, which has b‐cell dysfunction at its core. Glucotoxicity affects pancreatic islets, causing b‐cell apoptosis. However, the role of JNK/β‐catenin signaling in glucotoxic b‐cell apoptosis is not well understood. Recently, we identified tetraspanin‐2 (TSPAN2) protein as a proapoptotic b‐cell factor induced by glucose, suggesting that TSPAN2 might contribute to pancreatic b‐cell glucotoxicity. To investigate the effects of glucose concentration on TSPAN2 expression and apoptosis, we used reverted immortalized RNAKT‐15 human pancreatic b cells. High TSPAN2 levels up‐regulated phosphorylated (p) JNK and induced apoptosis. p‐JNK enhanced the phosphorylation of β‐catenin and Dickkopf‐1 (Dkk1). Dkk1 knockdown by small interfering (si)RNA up‐regulated nuclear β‐catenin, suggesting that it is a JNK/β‐catenin‐dependent pathway. siRNA‐mediated TSPAN2 depletion in RNAKT‐15 cells increased nuclear β‐catenin. This decreased BCL2associated X protein (Bax) activation, leading to marked protection against high glucose–induced apoptosis. Bax subfamily proteins induced apoptosis through caspase‐3. Thus, TSPAN2 might have induced Bax translocation and caspase‐3 activation in pancreatic b cells, thereby promoting the apoptosis of RNAKT‐15 cells by regulating the JNK/ β‐catenin pathway in response to high glucose concentrations. Targeting TSPAN2 could be a potential therapeutic strategy to treat glucose toxicity‐induced b‐cell failure.—Hwang, I.‐H., Park, J., Kim, J.M., Kim, S. I., Choi, J.‐S., Lee, K.‐B., Yun, S. H., Lee, M.‐G., Park, S. J., Jang, I.‐S. Tetraspanin‐2 promotes glucotoxic apoptosis by regulating the JNK/β‐catenin signaling pathway in human pancreatic β cells. FASEB J. 30, 3107–3116 (2016). www.fasebj.org

Draft Genome Sequence of Petroleum Oil-Degrading Marine Bacterium Pseudomonas taeanensis Strain MS-3, Isolated from a Crude Oil-Contaminated Seashore

ABSTRACT Pseudomonas taeanensis MS-3T, isolated from a crude oil-contaminated seashore in South Korea, is capable of degrading petroleum oils, such as gasoline, diesel, and kerosene. Here, we report the draft genome sequence of this strain, which consists of 5,477,045 bp, with a G+C content of 60.72%.

Draft Genome Sequence of an Aniline-Degrading Bacterium, Burkholderia sp. K24

ABSTRACT Burkholderia sp. K24 is an aniline-degrading soil bacterium that utilizes aniline and its analogues as sole carbon and nitrogen sources. Here, we report the draft genome sequence of this strain that consists of 8,344,181 bp, with a G+C content of 61.7%.

Abstract 4853: Reduced expression of DRAM2/TMEM77 in tumor cells interferes with cell death

Although the role of autophagy in tumorigenesis remains controversial, recent reports support the notion that inhibition of autophagy promotes tumor formation. Damageregulated autophagy regulator (DRAM) has been identified as an effector molecule that is critical for p53-mediated apoptosis, and we investigated whether there might be other DRAM-like molecules linking autophagy and apoptosis. In this study, we cloned a novel DRAM-homologous protein, DRAM2, and showed that the expression of DRAM2 is down-regulated in ovarian tumors. DRAM2 is mainly localized in the lysosome, and colocalizes with DRAM. While expression of DRAM or DRAM2 individually did not induce cell death, co-expression of DRAM2 with DRAM significantly induced cell death, while the silencing of endogenous DRAM2 attenuated cell death, suggesting that DRAM2 is involved in cell death. Thus, we propose that reduced expression of DRAM2 may contribute to enhanced cell survival in tumor cells. Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4853.