• Korean Journal of Mathematics
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• v.31 no.2
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• pp.145-152
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• 2023

Let $P(z):=\sum\limits^{n}_{j=0}A_jz^j$, A_j ∈ ℂ^m×m, 0 ≤ j ≤ n be a matrix polynomial of degree n, such that A_n ≥ A_n-1 ≥ . . . ≥ A₀ ≥ 0, A_n > 0. Then the eigenvalues of P(z) lie in the closed unit disk. This theorem proved by Dirr and Wimmer [IEEE Trans. Automat. Control 52(2007), 2151-2153] is infact a matrix extension of a famous and elegant result on the distribution of zeros of polynomials known as Eneström-Kakeya theorem. In this paper, we prove a more general result which inter alia includes the above result as a special case. We also prove an improvement of a result due to Lê, Du, Nguyên [Oper. Matrices, 13(2019), 937-954] besides a matrix extention of a result proved by Mohammad [Amer. Math. Monthly, vol.74, No.3, March 1967].

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2004.11a
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• pp.163-164
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• 2004

• The Journal of Pediatrics of Korean Medicine
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• v.27 no.1
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• pp.59-68
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• 2013

Objectives The aim of this study is to investigate whether hwang-ryun-haedok-tang (HDT) affect proliferations of androgen-dependent LNCaP prostate cancer cells, androgen-independent PC-3, DU-145 prostate cancer cells, MCF-7 human breast cancer cells, A549, NCI-H292 human pulmonary cancer cells and K-562 human chronic myelogenous leukemia cells. Materials and Methods Effects of HDT on proliferations of each cancer cell line were investigated. 20,000 cells/well were plated in each well of 96-well culture plate. After 24 hrs, 0.01-10% of HDT in culture medium was added to cancer cells. The number of cells was counted by using SRB assay or direct cell counting method after 72 hours from drug treatment. Effect of baicalein or berebrine on proliferation was assessed according to the same method. Results (1) HDT inhibited proliferations of LNCaP, PC-3 and DU-145 prostate cancer cells. (2) HDT inhibited proliferation of MCF-7 breast cancer cells. (3) HDT also inhibited proliferations of A549, NCI-H292 pulmonary cancer cells and K-562 chronic myelogenous leukemia cells. (4) Baicalein and berberine also showed inhibitory effects on proliferations of prostate and breast cancer cells. Conclusion : HDT inhibited proliferations of human prostate, breast, pulmonary and blood cancer cells. These results suggest us the potential use of HDT as a chemopreventive or chemotherapeutic agent. Effect of HDT on human cancer should be further investigated using in vivo experimental models that can reflect pathophysiology of human cancer through another studies.

• Applied Microscopy
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• v.38 no.3
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• pp.245-250
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• 2008

Etoposide (Eto) is chemotherapeutic compounds that is currently used in the treatment of metastatic prostate cancer but new therapeutic agents are needed for the treatment of androgen-independent prostate cancer. The objective of the present study was to determine whether vitamin C (VC), the antioxidant, plays a role in regulating the growth of prostate cancer cell lines and whether VC has synergistic effect to tumor cell killing by chemotherapeutic drugs. Androgen-dependent LNCaP and androgen-independent DU-145 prostate cancer cell lines were used in this study. Both cells presented increase of dose- and time-dependent cytotoxicity in Eto-treated cultures. The combined treatment with Eto and VC significantly increased the percentage of apoptotic cells compared to Eto-treated cells(p<0.05). The present findings demonstrated that VC inhibited the growth of prostate cancer cell lines by Eto-mediated cytotoxicity and induced apoptosis. These results suggest that the chemotherapeutic effect of Eto on prostate cancer can be enhanced by VC.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.sup3
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• pp.125-130
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• 2016

Nepeta cataria L. has been used in traditional medicine of some countries. Here the cytotoxic and apoptogenic activity of methanol extracts, n-hexane, dichloromethane, ethyl acetate, n-butanol, and acqueous extracts and the essential oil obtained from the aerial parts of the plant were evaluated with PC3, DU-145 and MCF-7 cell lines. Cell viability, histograms of PI stained fragmented DNA in apoptotic cells and Western blot analysis of proteins involved in the cascade of apoptosis were compared in all samples. Thirty components were identified as volatile, representing 99.7% of essential oil composition after GC-MS analysis of the oil obtained from aerial parts of the N. cataria by hydro-distillation. The major oil components of the essential oil were nepetalactone stereoisomers. Comparing IC50 values showed estrogen receptor positive PC3 cells were more sensitive to the cytotoxic effects of N. cataria in comparison with low hormone-receptor presenting DU-145 cells. Among multiple extracts and essential oils of the plant, only the ethyl acetate extract could significantly decrease cell viability in PC3 cells, in a concentration dependent manner. Ethyl acetate extract of N. cataria treated cells showed a sub-G1 peak in PC3 cells in a concentration dependent manner that indicates the involvement of an apoptotic process in ethyl acetate extract-induced cell death. Western blotting analysis showed that in PC3 cells treated with ethyl acetate (48 h) caspase 3 and PARP were cleaved to active forms. Overall, the results suggest that further analytical elucidation of N. cataria in respect to finding new cytotoxic chemicals with anti-tumor activity is warranted.

• Biomolecules & Therapeutics
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• v.21 no.1
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• pp.49-53
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• 2013

A number of naturally-occurring or synthetic chemicals have been reported to exhibit prostate chemopreventive effects. Synthetic $5{\alpha}$-reductase (5-AR) inhibitors, e.g. finasteride and durasteride, gained special interests as possible prostate chemopreventive agents. Indeed, two large-scale epidemiological studies have demonstrated that finasteride or durasteride significantly reduced the incidence of prostate cancer formation in men. However, these studies have raised an unexpected concern; finasteride and durasteride increased the occurrence of aggressive prostate tumor formation. In the present study, we have observed that treatment of finasteride did not affect the growth of androgen-refractory PC-3 prostate cancer cells. Finasteride also failed to induce apoptosis or affect the expression of proto-oncogenes in PC-3 cells. Interestingly, we found that treatment of finasteride induced the expression of Nrf2 and HO-1 proteins in PC-3 cells. In particular, basal level of Nrf2 protein was higher in androgen-refractory prostate cancer cells, e.g. DU-145 and PC-3 cells, compared with androgen-responsive prostate cancer cells, e.g. LNCaP cells. Also, treatment of finasteride resulted in a selective induction of Nrf2 protein in DU-145 and PC-3 cells, but not in LNCaP cells. In view of the fact that upregulation of Nrf2-mediated phase II cytoprotective enzymes contribute to attenuating tumor promotion in normal cells, but, on the other hand, confers a selective advantage for cancer cells to proliferate and survive against chemical carcinogenesis and other forms of toxicity, we propose that finasteride-mediated induction of Nrf2 protein might be responsible, at least in part, for an increased risk of high-grade prostate tumor formation in men.

• Korean Journal of Materials Research
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• v.20 no.3
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• pp.132-136
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• 2010

This study examined the biostability and drug delivery efficiency of g-$Fe_2O_3$ magnetic nanoparticles (GMNs) by cytotoxicity tests using various tumor cell lines and normal cell lines. The GMNs, approximately 20 nm in diameter, were prepared using a chemical coprecipitation technique, and coated with two surfactants to obtain a water-based product. The particle size of the GMNs loaded on hangamdan drugs (HGMNs) measured 20-50 nm in diameter. The characteristics of the particles were examined by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-TEM) and Raman spectrometer. The Raman spectrum of the GMNs showed three broad bands at 274, 612 and $771\;cm^1$. A 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay showed that the GMNs were non-toxic against human brain cancer cells (SH-SY5Y, T98), human cervical cancer cells (Hela, Siha), human liver cancer cells (HepG2), breast cancer cells (MCF-7), colon cancer cells (CaCO2), human neural stem cells (F3), adult mencenchymal stem cells (B10), human kidney stem cells (HEK293 cell), human prostate cancer (Du 145, PC3) and normal human fibroblasts (HS 68) tested. However, HGMNs were cytotoxic at 69.99% against the DU145 prostate cancer cell, and at 34.37% in the Hela cell. These results indicate that the GMNs were biostable and the HGMNs served as effective drug delivery vehicles.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.1
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• pp.1-7
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• 2007

Antimutagenic and in vitro anticancer effects of doenjangs added with green tea extract and/or using bamboo salt were studied by Ames test using Salmonella enterica serovar Typhimurium (Salmonella Typhimurium) TA100 and 3-(4,5-dimethylthiazol) -2,5-diphenyltetrazolium bromide (MTT) assay on PC-3 and DU145 human prostate cancer cells, respectively. At the 1.25 mg/plate concentration, 1% green tea extract (GTE) added doenjang exhibited 85% antimutagenicity against aflatoxin $B_1$ ($AFB_1$), while the control doenjang revealed 63% antimutagenicity, showing increased antimutagenic effect by the addition of green tea extract during doenjang fermentation. GTE added doenjang also increased antimutagenic effect against MNNG. The inhibition rate of the control doenjang showed 34% at 0.625 mg/plate, while 1% and 2% GTE added doenjangs inhibited by 56% and 73% at the 0.625 and 1.25 mg/plate, respectively (p<0.05). In MTT assay, GTE added doenjangs caused 70% $\sim$ 77% inhibition on the proliferation of PC-3 human prostate cancer cells at 0.5 mg/mL while the control doenjang exhibited 46% inhibition. However, 2% GTE added doenjang showed 91% inhibition at 1.0 mg/mL. The trend of the inhibition rate was similar in DU14S human prostate adenocarcinoma cells. When bamboo salt was used instead of natural sea salt, the antimutagenicity against MNNG and in vitro anticancer effect on the prostate cancer cells greatly increased. From these results, it can be concluded that green tea extract addition to doenjang and the use of bamboo salt during doengjang preparation increased the antimutagenic and in vitro anticancer activities of the doenjang and showed a synergistic effect.

• BMB Reports
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• v.32 no.2
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• pp.173-180
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• 1999

The effects of agmatine on the enzymes responsible for the biosynthesis of polyamines, the resultant levels of polyamines, and their effect on the growth of DU145 human prostate tumor cells were investigated. When agmatine was added to the medium, ornithine decarboxylase (ODC, EC 4.1.1.17) activity was substantially reduced, but S-adenosylmethionine decarboxylase (SAMDC, EC 4.1.1.50) activity increased markedly. These changes in ODC and SAMDC activities were the result of an induction of ODC-antizyme and a decreased turnover rate of SAMDC in the presence of agmatine. Accordingly, there was a decrease in the intracellular levels of putrescine and spermidine but an increase in the intracellular level of spermine. Cell growth was markedly inhibited by agmatine treatment and this inhibition was not recovered by the addition of putrescine or spermidine. Our results suggest that agmatine alters the intracellular amounts of polyamine in the cells, closely related to the inhibition of cell growth.

• Proceedings of the Korean Society of Environment and Ecology Conference
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• 2010.04a
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• pp.142-145
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• 2010