• The Korean Journal of Physiology and Pharmacology
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• 제22권5호
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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.

• Biomolecules & Therapeutics
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• 제15권3호
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• pp.145-149
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• 2007

We have previously shown that 2,4,3',5'-tetramethoxystilbene (TMS), a synthetic trans-stilbene analogue acting as a potent inhibitor of human cytochrome P450 1B1, induces apoptotic cell death in human cancer cells. In the present studies, we report the mechanisms of apoptotic cell death by TMS in human promyelocytic leukemic HL-60 cells. We found that treatment of HL-60 cells with TMS suppressed the cell growth in a concentration-dependent manner with $IC_{50}$ value of about 0.8 ${\mu}M$. Immunoblot experiments revealed that DMHS-induced apoptosis was associated with cleavage of poly (ADP-ribose) polymerase. The release of cytochrome c from mitochondria into the cytosol was significantly increased in response to TMS. TMS caused activation of caspase-3 in a concentration-dependent manner and TMS-mediated caspase-3 activation was partially prevented by the caspase inhibitor, zVAD-fmk. Interestingly, we found that the cytotoxic effect of anticancer drugs such as paclitaxel, docetaxel, or etoposide was enhanced in the presence of TMS. Simultaneous treatment with TCDD also significantly increased cytotoxic effects of TMS alone or TMS and anti-cancer agents. Taken together, our present results indicated that TMS leads to apoptotic cell death in HL-60 cells through activation of caspase-3 activity and release of cytochrome c into cytosol. The ability of TMS to increase cytotoxic effect of anticancer drugs may contribute to its usefulness for cancer chemotherapy.

• Journal of Chest Surgery
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• 제26권1호
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• pp.47-53
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• 1993

The high relapse rate after curative surgery of lung cancer suggests that tumor cells are remained at the site of resection and in the distant organs. Postoperative radiochemoimmunotherapy including protein-bound polysaccharide PS-K[Copolang] and/or chemotherapy to improve the prognosis in lung cancer has been adopted. The patients with lung cancer who were treated with a combined modality therapy after surgery were reviewed to determine the effects of adjuvant immunotherapy[PS-K] and the relationship between midterm survival and clinicopathologic variables. During the past 5 years, 95 patients with lung cancer underwent resective operation. Of them, 30 cases were curative surgery, 29 were relative curative surgery, and the remainders were non-curative surgery. Postoperative combination therapies consisted of three types of therapies: postoperative BRM[biological response modifiers] with PS-K [Copolang] 50 mg/kg for 24 weeks[Group 1], chemoimmunotherapy with chemotherapy[a combination of cisplatin, etoposide, vindesine] and PS-K [Group 2], radioimmunotherapy with postoperative prophylactic irradiation to the mediastinum at total dose of 54 Gy-60 Gy and PS-K [Group 3] and surgery without adjuvant therapy[Group 4]. Twenty months survival rates of localized disease [Stages I and II] treated with PS-K, with radioimmunotherapy and no therapy were 73 %, 60 %, and 50 %, respectively [p [0.05]. Three-year survival rates of regionally advanced cases [stage Ilia and IIIb] were 23 % in Group 1.57 % in Group 2.20 % in Group 3, and 0 % in Group 4, respectively.According to above results, we suggest that postoperative combination therapy including PS-K might improve the prognosis of lung cancer. The similar survival pattern of patients with squamous cell carcinoma and adenocarcinoma treated with BRM, chemoimmunotherapy or radioimmunotherapy need to evaluate the role of postoperative immunotherapy[PS-K] in randomized studies.

• Molecules and Cells
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• 제24권2호
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• pp.261-267
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• 2007

Apoptotic signals are typically accompanied by activation of aspartate-specific cysteine proteases called caspases, and caspase-3 and -7 play crucial roles in the execution of apoptosis. Previously, using the proteomic approach, protein disulfide isomerase (PDI) was found to be a candidate substrate of caspase-7. This abundant 55 kDa protein introduces disulfide bonds into proteins (via its oxidase activity) and catalyzes the rearrangement of incorrect disulfide bonds (via its isomerase activity). PDI is abundant in the ER but is also found in non-ER locations. In this study we demonstrated that PDI is cleaved by caspase-3 and -7 in vitro. In addition, in vivo experiment showed that it is cleaved during etoposide-induced apoptosis in HL-60 cells. Subcellular fractionation showed that PDI was also present in the cytosol. Furthermore, only cytosolic PDI was clearly digested by caspase-3 and -7. It was also confirmed by confocal image analysis that PDI and caspase-7 partially co-localize in both resting and apoptotic MCF-7 cells. Overexpression of cytosolic PDI (ER retention sequence deleted) inhibited cell death after an apoptotic stimulus. These data indicate that cytosolic PDI is a substrate of caspase-3 and -7, and that it has an anti-apoptotic action.

• 대한한의학회지
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• 제23권1호
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• pp.24-36
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• 2002

Objectives: The chemotherapeutic potential of Gagamgilgyung-tang for the treatment of human lung cancer, the antitumorigenic effects of Gagamgilgyung-tang on the proliferation and apoptosis of human lung cancer cell line A427 were investigated using molecular biological approaches, Methods: To determine Gagamgilgyung-tang concentrations which do not evoke cytotoxic damage to the cell line, cell viability was examined by MTT assay. To prove Gagamgilgyung-tang's antitumorigenic potential to human lung cancer, [3H]thymidine incorporation assay, trypan blue exclusion and Cpp32 protease activity assays and quantitative RT-PCR analysis were examined. Results: While A427 cells treated with $0.1-2.0{\mu\textrm{g}}/ml$ of Gagamgilgyung-tang showed no recognizable effect, marked reductions of cell viability were detected at concentrations over $5.0{\;}\mu\textrm{g}/ml$. DNA replication of A427 cells was inhibited by Gagamgilgyung-tang in a dose-dependent manner and Gagamgilgyung-tang induced the G1 cell cycle arrest through inhibition of DNA replication. Gagamgilgyung-tang triggered apoptotic cell death of A427 and enhanced the apoptotic sensitivity of the cells that were injured by a DNA damage-inducing chemotherapeutic drug etoposide. Gagamgilgyung-tang induces expression of growth-inhibiting genes such as p53 and p21/Wafl whereas it inhibited expression of growth-promoting genes such as c-Myc and Cyclin D1. Expression of a representative apoptosis-inducing gene Bax was also found to be induced by Gagamgilgyung-tang while apoptosis-suppressing Bcl-2 expression was not changed. Conclusions: Gagamgilgyung-tang could suppress the abnormal growth of tumor cells by suppressing the survival of genetically altered cells via induction of apoptosis. This study suggests that Gagamgilgyung-tang might have an antitumorigenic potential to human lung cancer cells, which might be associated with its growth-inhibiting and apoptosis-inducing properties.

• 한국식품영양과학회:학술대회논문집
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• 한국식품영양과학회 2001년도 International Symposium on Food,Nutrition and Health for 21st Century
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• pp.69-73
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• 2001

Two opioid peptides, YPLDL and YPLDLF, were isolated from enzymatic digests of spinach ribulose-1, 5-bisphosphate carboxylase/oxygenase (RuBisCO) and named rubiscolin-5 and -6, respectively. These peptides were selective for delta-receptor and the latter was about 3 times more potent than the former. After oral administration in mice at the dose of 100 mg/kg, rubiscolin-6 showed analgesic activity in tail pinch test. It also stimutated learning performance at the same dose in passive avoidance experiment using step-through apparatus. An immunostimulating peptide, MITLAIPVNKPGR, was isolated from a trypsin digest of soybean protein and named soymetide. Immunostimulating activy of soymetide was mediated by fMLP receptor. Interestingly, after oral administration in rats at a dose of 300 mg/kg (po.), soymetide-4 (MITL) protected alopecia (hair-loss) induced by etoposide, a cancer chemotherapy agent. Stimulation of IL-1 release by the peptide was involved in the mechanism. Ovokinin(2-7), RADHPF, is a vasorelaxing peptide released from ovalbumin by the action of chymotrypsin. It lowered blood pressure of spontaneously hypersensive rats (SHR) after oral administration at a dose of 10 mg/kg. RPLKPW, which was designed by replacing 4 amino acid residues in ovokinin(2-7), exhibited hypotensive activity at a dose of 0.1 mg/kg (po.). This peptides was introduced into 3 homologous sites in soybean beta-conglycinin alpha' subunit by site-directed mutagenesis of the cDNA and expressed in E. coli. The minimum effective dose for hypotensive activity of the genetically modified beta-conglycinin alpha' subunit was 10 mg/kg (po.), which is about 1/200 that of ovalbumin.

• Bulletin of the Korean Chemical Society
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• 제30권7호
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• pp.1463-1469
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• 2009

Eleven novel oxiranyl and thiiranyl phenolic compounds were synthesized as potential antitumor agents using epichlorohydrin and epithiohydrin in the presence of $K_2CO_3$. Cytotoxicities were found in range of I$C_{50}$ values of 2.5-14.8 $\mu$M, which was partially attributed to topoisomerase II inhibition. Bis-thiiranyl anthraquinone analog, 19 showed more cytotoxicity against MDA-MB-231 (breast cancer cell) and PC3 (prostate cancer cell) after 24 and/or 48 h and more potent topoisomerase II inhibitory activity than etoposide.

• 약학회지
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• 제35권3호
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• pp.203-215
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• 1991

Using the calorimetric [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] (MTT)assay, we evaluated the chemosensitivity of 8 anticancer drugs{vincristine(VCR), vinblastine(VBL), adriamycin(ADR), cisplatin(CPDD), etoposide(VP-16), cytosine arabinoside(ara-C), bleomycin (Bleo) and cyclophosphamide(CYC)} and the cytotoxicity-enhancing effects of ($\pm$)-ar-turmerone and the extracts of the crude drugs {Lithospermum eythrorhizon(LE) and Scutellaria baicalensis (SB)} on the above mentioned anticancer drugs against HL-60 and KG-1 cells among 8 anticancer drugs, VCR, VBL, ADR, and CPDD inhibited the growth of both cell lines by more than 50%, while VP-16, ara-C, Bleo, and CYC were less effective. ($\pm$)-ar-Turmerone had significant inhibitory effects against both cell lines, showing the ID$_{50}$ values of 11.730 $\mu\textrm{g}$/ml and 0.292 $\mu\textrm{g}$/ml for HL-60 and KG-1 cells. respectively. But the extracts of LE and SB roots showed no significant cytotoxic effects. According to ID$_{50}$ values, the cytotoxicities of VCR, VBL and ADR against HL-60 were enhanced two, eight and three times by mixing ($\pm$)-ar-turmerone, five, seven and three times by adding the extract of LE root, and twenty, six and three times by mixing the extract of SB root, respectively. The cytotoxicities of the above mentioned drugs against KG-1 cell were enhanced two, seven and three times by mixing ($\pm$)-ar-turmerone, two, three and three times by combining wilth the extract of LB root, and two, five and two times by adding the extract of SB root, respectively. The cytotoxicity-potentiating effects of ($\pm$)-ar-turmerone and the extracts of LE and SB roots against HL-60 cell were greater than KG-1 cell.

• 한국식품과학회지
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• 제35권4호
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• pp.680-683
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• 2003

한약재로부터 U937 세포주를 사용한 caspase-3 유도저해물질을 탐색한 결과 소목(Caesalpiniae sappan)을 선발하였다. 소목의 메탄올 추출물로부터 silica gel column chromatography, HPLC 등을 사용하여 저해물질을 분리하였으며, ESI-MS, $^1H-NMR,\;^{13}C-NMR$ 등의 기기분석을 실시하여 brazilin이 동정되었다. 이 물질은 $IC_{50}\;4.5\;{\mu}g/mL$의 농도로 U937세포주의 etoposide에 의한 caspase-3 유도를 저해하였으며, DPPH 라디칼 소거능도 나타내었다.

• 한국식품과학회지
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• 제32권2호
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• pp.448-453
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• 2000

천연물로부터 U937 세포주를 사용한 caspase-3 유도저해물질을 탐색한 결과 머위(Petasites japonicum)를 선발하였다. 머위의 메탄올 추출물로부터 Sephadex LH-20 column chromatography, HPLC 등을 사용하여 저해물질을 분리하였으며, UV, EIMS, 1H-NMR, $^{13}C-NMR$, HMBC등의 기기분석을 실시한 결과 [3-(3,4-dihydroxyphenyl)-2-oxopropyl] ester로 동정되었다. 이 물질은 $IC_{50}\;8\;{\mu}g/ml$의 농도로 U937 세포주의 etoposide에 의한 caspase 3 유도를 저해하였으며, DNA fragmentation도 저해하였다. 또한 1,1-diphenyl-2-picrylhydrazyl(DPPH) 라디칼 소거능을 나타내었다.