• IMMUNE NETWORK
• /
• v.13 no.5
• /
• pp.194-198
• /
• 2013

Recent papers have shown that the initial event in the pathogenesis of autoimmune type 1 diabetes (T1D) comprises sensing of molecular patterns released from apoptotic ${\beta}$-cells by innate immune receptors such as toll-like receptor (TLR). We have reported that apoptotic ${\beta}$-cells undergoing secondary necrosis called 'late apoptotic' ${\beta}$-cells stimulate dendritic cells (DCs) and induce diabetogenic T cell priming through TLR2. The role of other innate immune receptors such as TLR7 or TLR9 in the initiation of T1D has also been suggested. We hypothesized that TLR2 blockade could inhibit T1D at the initial step of T1D. Indeed, when a TLR2 agonist, $Pam3CSK_4$ was administered chronically, the development of T1D in nonobese diabetic (NOD) mice was inhibited. Diabetogenic T cell priming by DCs was attenuated by chronic treatment with $Pam3CSK_4$, indicating DC tolerance. For the treatment of established T1D, immune tolerance alone is not enough because ${\beta}$-cell mass is critically reduced. We employed TLR2 tolerance in conjunction with islet transplantation, which led to reversal of newly established T1D. Dipeptidyl peptidase 4 (DPP4) inhibitors are a new class of anti-diabetic agents that have beneficial effects on ${\beta}$-cells. We investigated whether a combination of DPP4 inhibition and TLR2 tolerization could reverse newly established T1D without islet transplantation. We could achieve normoglycemia by TLR2 tolerization in combination with DPP4 inhibition but not by TLR2 tolerization or DPP4 inhibition alone. ${\beta}$-cell mass was significantly increased by combined treatment with TLR2 tolerization and DPP4 inhibition. These results suggest the possibility that a novel strategy of TLR tolerization will be available for the inhibition or treatment of established T1D when combined with measures increasing critically reduced ${\beta}$-cell mass of T1D patients such as DPP4 inhibition or stem cell technology.

• Environmental Mutagens and Carcinogens
• /
• v.24 no.2
• /
• pp.51-66
• /
• 2004

Retinoids, better known as vitamin A, have been reported to inhibit the growth of several breast cancer cell lines in culture and to reduce breast tumor growth in animal models. Furthermore, retinoids can augment the action of other breast cancer cell growth inhibitors both in vitro and in vivo. Clinically, interest has increased in the potential use of retinoids for the prevention and treatment of human breast cancer. We have examine the effect of all-trans retinoic acid(tRA) and 9-cis retinoic acid(9-cis RA) on human breast cancer cell(MCF-10A, T47-D, MCF-7) proliferation using MTT assay and cell cycle analysis(FACS). Overexpression of cyclin D1 protein is observed in the majority of breast cancers, suggesting that dysregulated expression of cyclin D1 might be a critical event in breast cancer carcinogenesis. We investigated whether tRA and 9-cis RA might affect expression of cyclin D1 on human breast cancer cells(MCF-10A, T47-D, MCF-7) using RT-PCR and west-ern bolt. In MCF-10A cells, either tRA or 9-cis RA treatment did not affect the cell proliferation. In T47-D cells and MCF-7 cells, either tRA or 9-cis RA treatment showed the inhibition of the cell proliferation over control cells and also inhibit the estrogen stimulated cell proliferation when it was given together with estrogen. The effect of retinoids was dose- and time- dependent. T47-D cells treated with 1.0 $\muM$ tRA undergo G0/G1-phase arrest by Day 5. MCF-7 cells treated with 1.0 $\muM$ tRA undergo S-phase arrest by Day 5. All-trans retinoic acid(tRA) and 9-cis retinoic acid(9-cis RA) inhibited the cyelin D1 mRNA and protein expression levels of human MCF-7 and T47-D breast carcinoma cells in vitro. The data indicate that retinoids can reduce cyclin D1 expression levels in a variety of breast cell lines in vitro and result in inhibition of cell proliferation. tRA-mediated growth inhibition and cyclin D1 expression inhibition is more potent than 9-cis RA mediated that. tRA-mediated inhibition effect is more potent on T47-D cells than on MCF-7 cells. Our data suggest that retinoids activity is different according to property of cell lines. Future chemoprevention of breast cancer studies using retinoids will be necessary to determine the mechanism of the retinoids-mediated growth inhibition.

• Asian Pacific Journal of Cancer Prevention
• /
• v.17 no.5
• /
• pp.2683-2688
• /
• 2016

A salt compound of a curcumin analogue, potassium pentagamavunon-0 (K PGV-0) has been synthesized to improve solubility of pentagamavunon-0 which has been proven to have anti-proliferative effects on several cancer cells. The purpose of this study was to investigate cytotoxic activity and metastasis inhibition by K PGV-0 alone and in combination with achemotherapeutic agent, doxorubicin (dox), in breast cancer cells. Based on MTT assay analysis, K PGV-0 showed cytotoxic activity in T47D and 4T1 cell lines with $IC_{50}$ values of $94.9{\mu}M$ and $49.0{\pm}0.2{\mu}M$, respectively. In general, K PGV-0+dox demonstrated synergistic effects and decreased cell viability up to 84.7% in T47D cells and 62.6% in 4T1 cells. Cell cycle modulation and apoptosis induction were examined by flow cytometry. K PGV-0 and K PGV-0+dox caused cell accumulation in G2/M phase and apoptosis induction. Regarding cancer metastasis, while K PGV-0 alone did not show any inhibition of 4T1 cell migration, K PGV-0+dox exerted inhibition. K PGV-0 and its combination with dox inhibited the activity of MMP-9 which has a pivotal role in extracellular matrix degradation. These results show that a combination of K PGV-0 and doxorubicin inhibits cancer cell growth through cell cycling, apoptosis induction, and inhibition of cell migration and MMP-9 activity. Therefore, K PGV-0 may have potential for development as a co-chemotherapeutic agent.

• The Korean Journal of Physiology and Pharmacology
• /
• v.2 no.5
• /
• pp.601-609
• /
• 1998

The present study was undertaken to examine the role of phospholipase $A_2\;(PLA_2)$ in oxidant-induced inhibition of phosphate transport in primary cultured rabbit renal proximal tubule cells. Uptakes of phosphate and glucose were dose-dependently inhibited by an oxidant t-butylhydroperoxide (tBHP), and the significant inhibition appeared at 0.025 mM of tBHP, whereas tBHP-induced alterations in lipid peroxidation and cell viability were seen at 0.5 mM. tBHP stimulated arachidonic acid (AA) release in a dose-dependent fashion. A $PLA_2$ inhibitor mepacrine prevented tBHP-induced AA release, but it did not alter the inhibition of phosphate uptake and the decrease in cell viability induced by tBHP. tBHP-induced inhibition of phosphate transport was not affected by a PKC inhibitor, staurosporine. tBHP at 0.1 mM did not produce the inhibition of $Na^+-K^+-ATPase$ activity in microsomal fraction, although it significantly inhibited at 1.0 mM. These results suggest that tBHP can inhibit phosphate uptake through a mechanism independent of $PLA_2$ activation, irreversible cell injury, and lipid peroxidation in primary cultured rabbit renal proximal tubular cells.

• Ecology and Resilient Infrastructure
• /
• v.9 no.3
• /
• pp.183-193
• /
• 2022

The growth inhibitory effect of Microcystis aeruginosa according to the ultrasonic irradiation time was evaluated using a large algae sample volume (10 L) for various ultrasonic irradiation times (0.5, 1, 1.5, 2, 2.5 and 3 hr) at a laboratory scale. Based on the analysis of Chl-a and cell number of M. aerginosa, algae growth inhibition was observed with the decrease in Chl-a and cell number in all experimental groups after the ultrasonic irradiation. For the experimental group (T_B, T_C, T_D) with an ultrasonic irradiation time of less than 2 hours, rapid regrowth of algae was observed after growth inhibition, but the experimental group (T_E, T_F, T_G) with an irradiation time of more than 2 hours successfully inhibited algal growth lasting one or two more days. Based on the comparison of the recovery time to initial cell number the experimental group (T_B, T_C, T_D) took less than 20 days whereas the experimental group (T_E, T_F, T_G) took about 30 days. Correspondingly, the experimental group showed a high first order decay rate (𝜅) in proportion to the ultrasonic irradiation time during the growth inhibition period. Additionally, the specific growth rates (𝜇) during regrowth in the experimental group with irradiation time of more than 2 hours were relatively low compared to those in the experimental group with less than 2 hours. Therefore, ultrasonic irradiation for more than 2 hours is required for long-term (30 days) inhibition of algal growth in stagnant waters. However, the appropriate ultrasonic irradiation time for algae growth inhibition should be determined according to various field conditions such as the volume of stagnant water, water depth, flow rate, algae concentration, etc. Finally, damages to the algal cell surface and cell membrane were clearly observed, and both destruction and disturbance of gas vesicles of M. aeruginosa in the experimental group were discovered, indicating the growth inhibitory effect of Microcystis aeruginosa according to the ultrasonic irradiation time was confirmed.

• YAKHAK HOEJI
• /
• v.37 no.4
• /
• pp.389-396
• /
• 1993

An Actinomycetes strain JB isolated from Mt. Hanla had a strong antimicrobial activity against gram positive bacteria and tumor cell growth inhibition. Especially, it couldn't degrade starch and casein as organic compounds. It was resist on lincomycin and rifampicin. The spore mass of strain JB which was arethrospore was white. DAP of the cell wall was L, L-DAP. Antimicrobial material was heat stable, dissolved in ethyl acetate, and not dissolved in butanol. In the pressnce of 0.1% phenol and 4% sodium chloride, strain JB could grow, but it didn't growth at below $10^{\circ}C$. Strain JB didn't use dextran, sodium acetate and sodium citrate as sole carbon source and L-cystein and L-thereonine as nitrogen source. The filtered broth of strain JB had the antimicrobial activity against gram positive bacteria, especially Staphylococcus aureus (ATCC 65389) and the growth inhibition of tumor cell line.

• Journal of Microbiology
• /
• v.42 no.2
• /
• pp.111-116
• /
• 2004

It is known that Bacillus subtilis glutamyl-tRNA synthetase (GluRS) mischarges E. coli $tRNA_{1}$$^{Gln}$ with glutamate in vitro. It has also been established that the expression of B. subtilis GluRS in Escherichia coli results in the death of the host cell. To ascertain whether E. coli growth inhibition caused by B. subtilis GluRS synthesis is a consequence of Glu-$tRNA_{1}$$^{Gln}$ formation, we constructed an in vivo test system, in which B. subtilis GluRS gene expression is controlled by IPTG. Such a system permits the investigation of factors affecting E. coli growth. Expression of E. coli glutaminyl-tRNA synthetase (GlnRS) also amelio-rated growth inhibition, presumably by competitively preventing $tRNA_{1}$$^{Gln}$ misacylation. However, when amounts of up to 10 mM L-glutamine, the cognate amino acid for acylation of $tRNA_{1}$$^{Gln}$, were added to the growth medium, cell growth was unaffected. Overexpression of the B. subtilis gatCAB gene encoding Glu-$tRNA^{Gln}$ amidotransferase (Glu-AdT) rescued cells from toxic effects caused by the formation of the mis-charging GluRS. This result indicates that B. subtilis Glu-AdT recognizes the mischarged E. coli Glu-$tRNA_{1}$$^{Gln}$, and converts it to the cognate Gln-$tRNA_{1}$$^{Gln}$ species. B. subtilis GluRS-dependent Glu-$tRNA_{1}$$^{Gln}$ formation may cause growth inhibition in the transformed E. coli strain, possibly due to abnormal protein synthesis.

• Biomedical Science Letters
• /
• v.10 no.4
• /
• pp.341-346
• /
• 2004

Tumor necrosis factor-α (TNF-α) or its mRNA expression are increased in acute nephrosis of various types including ischemia/reperfusion injury. This study was undertaken to determine whether pentoxifylline (PTX), an inhibitor of TNF-α production, provides a protective effect against hypoxia-induced cell injury in rabbit renal cortical slices. To induce hypoxia-induced cell injury, renal cortical slices were exposed to 100% N₂ atmosphere. Control slices were exposed to 100% O₂ atmosphere. The cell injury was estimated by measuring lactate dehydrogenase (LDH) release and p-aminohippurate (PAH) uptake. Exposure of slices to hypoxia increased the LDH release in a time-dependent manner. However, when slices were exposed to hypoxia in the presence of PTX, the LDH release was decreased. The protective effect of PTX was dose-dependent over the concentrations of 0.05∼1 mM. Hypoxia did not increase lipid peroxidation, whereas an organic hydroperoxide t-butylhydroperoxide (tBHP) resulted in a significant increase in lipid peroxidation. PTX did not affect tBHP-induced lipid peroxidation. Hypoxia decreased PAH uptake, which was significantly attenuated by PTX and glycine. tBHP-induced inhibition of PAH uptake was not altered by PTX, although it was prevented by antioxidant deferoxarnine. The PAH uptake by slices in rabbits with ischemic acute renal failure was prevented by PTX pretreatment. These results suggest that PTX may exert a protective effect against hypoxia-induced cell injury and its effect may due to inhibition of the TNF-α production, but not by its antioxidant action.

• Food Science and Biotechnology
• /
• v.17 no.3
• /
• pp.598-602
• /
• 2008

Concentrated catfish Silurus asotus bile (SAB) containing high amounts of ursodeoxycholic acid (UDCA) and taurocholic acid may have immunosuppressive properties. To investigate the putative immunosuppressive properties of SAB, the anti-proliferation and suppression of early T cell activation markers, and the inhibition of cytokines induced by T cells in response to anti-CD3 mAb activation in mouse splenocytes were examined. The suppression of these activation repertoires are the main properties of calcineurin inhibitors. It was found that SAB effectively suppressed the activation of T cells, and cytokines from T cell activation, at levels similar to cyclosporine A, a calcineurin inhibitor. Although the mechanism in which suppression occurs is not clear, we speculate that SAB from Silurus asotus, which has been known to switch their intake habits to zoophagy during an early adult stage, may explain the suppressive effect of SAB as a result of high amounts of functional UDCA in bile. Our results suggest that the treatment or intake of SAB, either in therapy or as a food supplement, may act as an adjuvant therapy for the prevention of transplant rejection, although further investigation is required before this treatment can be applied clinically.

• Journal of Acupuncture Research
• /
• v.17 no.3
• /
• pp.176-187
• /
• 2000

Objectives : This study was purposed to investigate the antioxidative effects of Paeoniae radix aqua-acupuncture solution(PR) on culture liver cell system, lipid peroxidation and antioxidative enzyme activities in tert-butyl hydroperoxide(t-BHP) treatmented conditions. Methods : Cultured normal rat liver cell(Ac2F) were prepared and incubated with or without PR(at 2% volume in culture medium). After 16~18hr, cells placed in DMEM medium without serum, and then incubated with 1mM t-BHP for 2hr. Viable cells were detected by MTT assay, and the levels of lipid peroxide(LPO) were measured by TBA method. And catalase activity was measured as the decrease in hydrogen peroxide absorbance at 240nm on spectrophotometer using 30mM hydrogen peroxide. Superoxide dismutase(SOD) were assayed by recording the inhibition of nitro blue tetrazolium reduction with xanthine and xanthine oxidase. Glutathione peroxidase(GPX) activity was determined by the modified coupled assay developed by Paglia and Lawrence. The reaction was started by addition of 2.2mM hydrogen peroxide as substrate. The change in absorbance at 340nm was measured for 1min on spectrophotometer. Glutathione-S-transferase(GST) activity was assayed with CDNB as substrate and enzyme activity of GST towards the glutathione conjugation of CDNB. Results : Cell killing was significantly enhanced by addition of t-BHP compared to those of untreated group. PR pretreated cell resisted the toxic effects of t-BHP. LPO levels of t-BHP treatment group were significantly higher than other groups. This increased level was significandy reduced by PR pretreatment. The t-BHP treatment resulted in a decrease of catalase, GPX and GST activities. By contrast, PR pretreatment markedly increased compare to those of untreated groups. Conclusions : T-BHP which can produce intracellular free radical was used for inducer of the peroxidation of cellular lipids. PR protected the cell death induced by t-BHP and significantly increased cell viabiliry in the normal rat liver cell, and showed effective inhibition of lipid peroxidation, and elevations of catalase, GPX and GST activities. These results suggested that PR might play a protective role in lipid peroxidation by free radicals.