• The Korean Journal of Physiology and Pharmacology
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• v.22 no.5
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• pp.513-523
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• 2018

The tumor microenvironment greatly influences cancer cell characteristics, and acidic extracellular pH has been implicated as an essential factor in tumor malignancy and the induction of drug resistance. Here, we examined the characteristics of gastric carcinoma (GC) cells under conditions of extracellular acidity and attempted to identify a means of enhancing treatment efficacy. Acidic conditions caused several changes in GC cells adversely affecting chemotherapeutic treatment. Extracellular acidity did inhibit GC cell growth by inducing cell cycle arrest, but did not induce cell death at pH values down to 6.2, which was consistent with down-regulated cyclin D1 and up-regulated p21 mRNA expression. Additionally, an acidic environment altered the expression of atg5, HSPA1B, collagen XIII, collagen XXAI, slug, snail, and zeb1 genes which are related to regulation of cell resistance to cytotoxicity and malignancy, and as expected, resulted in increased resistance of cells to multiple chemotherapeutic drugs including etoposide, doxorubicin, daunorubicin, cisplatin, oxaliplatin and 5-FU. Interestingly, however, acidic environment dramatically sensitized GC cells to apoptosis induced by tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). Consistently, the acidity at pH 6.5 increased mRNA levels of DR4 and DR5 genes, and also elevated protein expression of both death receptors as detected by immunoblotting. Gene silencing analysis showed that of these two receptors, the major role in this effect was played by DR5. Therefore, these results suggest that extracellular acidity can sensitize TRAIL-mediated apoptosis at least partially via DR5 in GCs while it confers resistance to various type of chemotherapeutic drugs.

• BMB Reports
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• v.40 no.5
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• pp.636-643
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• 2007

This study was designed to identify and characterize the mechanism of macrophage activation by AAP, an acidic polysaccharide fraction isolated from the roots of Angelica sinensis (Oliv.) Diels. As a result, AAP significantly enhanced nitric oxide (NO) production and cellular lysosomal enzyme activity in murine peritoneal macrophages in vitro and in vivo. Furthermore, L-NAME, a specific inhibitor of inducible nitric oxide synthase (iNOS), effectively suppressed AAP-induced NO generation in macrophages, indicating that AAP stimulated macrophages to produce NO through the induction of iNOS gene expression and the result was further confirmed by the experiment of the increase of AAP-induced iNOS transcription in a dose-dependent manner. To further investigate, AAP was shown to strongly augment toll-like receptor 4 (TLR4) mRNA expression and the pretreatment of macrophages with anti-TLR4 antibody significantly blocked AAP-induced NO release and the increase of iNOS activity, and tumor necrosis factor-$\alpha$ (TNF-$\alpha$) secretion.

• Journal of Ginseng Research
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• v.41 no.3
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• pp.247-256
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• 2017

Background: KG-135, a standardized formulation enriched with Rk1, Rg3, and Rg5 ginsenosides, has been shown to inhibit various types of cancer cells; however, the underlying mechanisms are not fully understood. In this study, we explored its effects in A549 human lung cancer cells to investigate the induction of Forkhead Class box O3a (FOXO3a) and autophagy. Methods: Cell viability was determined by sulforhodamine B staining. Apoptosis and cell cycle distribution were analyzed using flow cytometry. The changes of protein levels were determined using Western blot analysis. Autophagy induction was monitored by the formation of acidic vesicular organelles stained with acridine orange. Results: KG-135 effectively arrested the cells in G1 phase with limited apoptosis. Accordingly, a decrease of cyclin-dependent kinase-4, cyclin-dependent kinase-6, cyclin D1, and phospho-retinoblastoma protein, and an increase of p27 and p18 proteins were observed. Intriguingly, KG-135 increased the tumor suppressor FOXO3a and induced the accumulation of autophagy hallmark LC3-II and acidic vesicular organelles without an increase of the upstream marker Beclin-1. Unconventionally, the autophagy adaptor protein p62 (sequestosome 1) was increased rather than decreased. Blockade of autophagy by hydroxychloroquine dramatically potentiated KG-135-induced FOXO3a and its downstream (FasL) ligand accompanied by the cleavage of caspase-8. Meanwhile, the decrease of Bcl-2 and survivin, as well as the cleavage of caspase-9, were also drastically enhanced, resulting in massive apoptosis. Conclusion: Besides arresting the cells in G1 phase, KG-135 increased FOXO3a and induced an unconventional autophagy in A549 cells. Both the KG-135-activated extrinsic FOXO3a/FasL/caspase-8 and intrinsic caspase-9 apoptotic pathways were potentiated by blockade of autophagy. Combination of KG-135 and autophagy inhibitor may be a novel strategy as an integrative treatment for cancers.

• Development and Reproduction
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• v.21 no.2
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• pp.139-150
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• 2017

Metformin is the most commonly prescribed anti-diabetic drug with relatively minor side effect. Substantial evidence has suggested that metformin is associated with decreased cancer risk and anticancer activity against diverse cancer cells. The tyrosine kinase inhibitor imatinib has shown powerful activity for treatment of chronic myeloid leukemia and also induces growth arrest and apoptosis in colorectal cancer cells. In this study, we tested the combination of imatinib and metformin against HCT15 colorectal cancer cells for effects on cell viability, cell cycle and autophagy. Our data show that metformin synergistically enhances the imatinib cytotoxicity in HCT15 cells as indicated by combination and drug reduction indices. We also demonstrate that the combination causes synergistic down-regulation of pERK, cell cycle arrest in S and $G_2/M$ phases via reduction of cyclin B1 level. Moreover, the combination resulted in autophagy induction as revealed by increased acidic vesicular organelles and cleaved form of LC3-II. Inhibition of autophagic process by chloroquine led to decreased cell viability, suggesting that induction of autophagy seems to play a cell protective role that may act against anticancer effects. In conclusion, our present data suggest that metformin in combination with imatinib might be a promising therapeutic option in colorectal cancer.

• Biomolecules & Therapeutics
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• v.32 no.1
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• pp.65-76
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• 2024

Bortezomib (BTZ) is a proteasome inhibitor used to treat multiple myeloma (MM). However, the induction of peripheral neuropathy is one of the major concerns in using BTZ to treat MM. In the current study, we have explored the effects of BTZ (0.01-5 nM) on rat neural stem cells (NSCs). BTZ (5 nM) induced cell death; however, the percentage of neurons was increased in the presence of mitogens. BTZ reduced the B-cell lymphoma 2 (Bcl-2)/Bcl-2 associated X protein ratio in proliferating NSCs and differentiated cells. Inhibition of βIII-tubulin (TUBB3) degradation was observed, but not inhibition of glial fibrillary acidic protein degradation, and a potential PEST sequence was solely found in TUBB3. In the presence of growth factors, BTZ increased cAMP response element-binding protein (CREB) phosphorylation, brain-derived neurotrophic factor (Bdnf) transcription, BDNF expression, and Tubb3 transcription in NSCs. However, in the neuroblastoma cell line, SH-SY5Y, BTZ (1-20 nM) only increased cell death without increasing CREB phosphorylation, Bdnf transcription, or TUBB3 induction. These results suggest that although BTZ induces cell death, it activates neurogenic signals and induces neurogenesis in NSCs.

• Food Science and Biotechnology
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• v.18 no.6
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• pp.1365-1370
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• 2009

Aspergillus kawachii extracellular pectinases were screened in liquid cultures with different carbon sources. The fungus grown on citrus pectin or lemon pomace produced at least one of these inducible pectinases: acidic polygalacturonase, pectin lyase, pectin methylesterase, $\alpha$-L-arabinofuranosidase, $\alpha$-1,5-endoarabinase, $\beta$-D-galactosidase/exogalactanase, and $\beta$-1,4-endogalactanase. The lemon-pomace filtrates also contained significant $\alpha$-L-rhamnosidase and $\beta$-D-fucosidase activities. Most of the screened pectinases were active at pH 2.0-2.5, indicating that the A. kawachii enzymes were acidophilic. Under the culture conditions employed we could not detect enzymatic degradation of soybean rhamnogalacturonan. The A. kawachii pectinase-production-related regulatory phenomena of induction-repression resemble those described for other Aspergillus sp.

• Bulletin of the Korean Chemical Society
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• v.11 no.4
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• pp.307-309
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• 1990

The stereoselectivity of the reaction between methyl vinyl ketone dimer, which contains two possible sites of chelation, and zinc borohydride or diisobutylaluminum hydride has been studied in order to illuminate the factors involved in the high levels of asymmetric induction obtained in the bicyclic system. The conditions for the formation of the exo-5,7-dimethyl-6,8-dioxabicyclo[3.2.1]octane are DIBAH reduction of MVK dimer in ether at reflux followed by acidic cyclizatioan, and for the endo isomer are $Zn(BH_4)_2$ reduction with $ZnCl_2$ at $0^{\circ}C.$.

• Korean Journal of Animal Reproduction
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• v.27 no.1
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• pp.15-23
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• 2003

Lactadherin (formerly known as BA46), a major glycoprotein of the human milk fat globule membrane, is abundant in human breast milk and breast carcinomas and may prevent symptomatic rotavirus infections. In this study, under the control of tissue specific and hormonal inducible mouse whey acidic protein (WAP) promote., the expression pattern of lactadherin (Ltd) in lactogenic hormone-dependent mouse mammary epithelial cell line HC11 were tested. pLNWLtd construct containing 2.4 kilobases of the WAP promoter and 1.5 kilobases of human lactadherin gene was stably transfered into HC11 cells using retroviral vector system. Integration and expression level of the transgene was estimated using PCR and RT-PCR, respectively. Prominent induction of Ltd gene under the WAP promoter was accomplished in the presence of insulin, hydrocortisone and prolactin. Compared to the control (cells cultured with insulin alone), however we observed that the WAP promoter was leaky. These data indicate that luther studies are needed in finding an appropriate promoter other than WAP promoter because of its leakiness.

• Journal of Dairy Science and Biotechnology
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• v.33 no.1
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• pp.83-91
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• 2015

Yogurt is a product of the acidic fermentation of milk, which affects the survival of lactic acid bacteria (LAB). The aim of this present study was to examine the survival and acid stress response of Lactobacillus rhamnosus GG to low pH environment. The survival of LAB in commercial yogurt was measured during long-term storage. The enumeration of viable cells of LAB was determined at 15-day intervals over 52-weeks at $5^{\circ}C$. L. acidophilus, L. casei, and Bifidobacterium spp. showed low viability. However, L. rhamnosus GG exhibited excellent survival throughout the refrigerated storage period. At the end of 52-weeks, L. rhamnosus GG survived 7.0 log10 CFU/mL. $F_0F_1$ ATPase activity in L. rhamnosus GG at pH 4.5 was also evaluated. The ATPase activities of the membranes were higher when exposed at pH 4.5 for 24 h. The survival of L. rhamnosus GG was attributable to the induction in $F_0F_1$ ATPase activity. In addition, the mRNA expression levels of acid stress-inducible genes at low pH were investigated by qRT-PCR. clpC and clpE genes were up-regulated after 1 h, and atpA and dnaK genes were up-regulated after 24 h of incubation at pH 4.5. These genes could enhance the survival of L. rhamnosus GG in the acidic condition. Thus, the modulation of the enzymes or genes to assist the viability of LAB in the low pH environment is thought to be important.

• Korean Journal of Plant Tissue Culture
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• v.21 no.2
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• pp.123-129
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• 1994

The potency of adventitious root initiation was investigated in relation with germination days and ike end of culture days healed with root induction medium on the initiation of adventitious roots from explants of soybean (Glycine max L.) cotyledon. Also, the changes in the pattern of protein profiles related with adventitious mot initiation have been examined by two-dimensional polyauyl-amide gel elecoophoresis during the germination and the initiation of adventitious roots. The potency of adventitious root initiation from germinated cotyledons was high after 4 days, and adventitious roots were initiated from after 4 days and very high after 6 days healed with mot induction medium There was a reproducible quantitative change in 34 specific protein spots during germination and adventitious root initiation. A necessary basic protein for adventitious root initiation with rotative molecular weight of 27 kD was induced during the germination. And three basic protein groups with relative molecular weight 22 kD, 23 kD and 33 kD, and two acidic protein groups with relative molecular weight 27kD and 29 kD were induced during the initiation of adventitious roots.