• BMB Reports
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• 제36권1호
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• pp.43-48
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• 2003

Understanding the process of carcinogenesis will involve both the accumulation of many scientific facts derived from molecular, biochemical, cellular, physiological, whole animal experiments and epidemiological studies, as well as from conceptual understanding as to how to order and integrate those facts. From decades of cancer research, a number of the "hallmarks of cancer" have been identified, as well as their attendant concepts, including oncogenes, tumor suppressor genes, cell cycle biochemistry, hypotheses of metastasis, angiogenesis, etc. While all these "hallmarks" are well known, two important concepts, with their associated scientific observations, have been generally ignored by many in the cancer research field. The objective of the short review is to highlight the concept of the role of human adult pluri-potent stem cells as "target cells" for the carcinogenic process and the concept of the role of gap junctional intercellular communication in the multi-stage, multi-mechanism process of carcinogenesis. With these two concepts, an attempt has been made to integrate the other well-known concepts, such as the multi-stage, multi-mechanisn or the "initiation/promotion/progression" hypothesis; the stem cell theory of carcinogenesis; the oncogene/tumor suppression theory and the mutation/epigenetic theories of carcinogenesis. This new "integrative" theory tries to explain the well-known "hallmarks" of cancers, including the observation that cancer cells lack either heterologous or homologous gap junctional intercellular communication whereas normal human adult stem cells do not have expressed or functional gap junctional intercellular communication. On the other hand, their normal differentiated, non-stem cell derivatives do express connexins and express gap junctional intercellular communication during their differentiation. Examination of the roles of chemical tumor promoters, oncogenes, connexin knock-out mice and roles of genetically-engineered tumor and normal cells with connexin and anti-sense connexin genes, respectively, seems to provide evidence which is consistent with the roles of both stem cells and gap junctional communication playing a major role in carcinogenesis. The integrative hypothesis provides new strategies for chemoprevention and chemotherapy which focuses on modulating connexin gene expression or gap junctional intercellular communication in the premalignant and malignant cells, respectively.

• Biomolecules & Therapeutics
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• 제11권4호
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• pp.224-231
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• 2003

The aim of this study was to investigate the effect of resveratrol on the oxidative stress-induced inhibition of gap junctional intercellular communication in HaCaT keratinocytes. Anti-oxidative activity of resveratrol was measured by $\alpha,\alpha$-diphenyl-$\beta$-picrylhydrazyl assay and dichlorodihydrofluorescein diacetate oxidation assay. Gap junctional intercellular communication in HaCaT keratinocytes was assessed using the scrape loading/dye transfer technique. Western blots and reverse transcription-polymerase chain reaction were also analyzed for connexin 43 protein and mRNA expression, respectively. Resveratrol scavenged directly the stable $\alpha,\alpha$-diphenyl-$\beta$-picrylhydrazyl radical over a concentration range of 4 mg/ml ($78.2{\pm}2.7$% of control) to 500 mg/ml ($29.9{\pm}4.2$% of control) and decreased the intracellular reactive oxygen species induced by ultraviolet A (UVA) irradiation ($89.3{\pm}1.1$% of UVA group), ultraviolet B (UVB) irradiation ($70.9{\pm}1.7$% of UVB group) and 12-0-tet-radecanoylphorbol-13-acetate (TPA, $48.3{\pm}1.1$% of TPA group), respectively. UVA irradiation and TPA markedly reduced gap junctional intercellular communication, which was restored by resveratrol. There were no significant differences in the level of connexin 43 protein and mRNA expression among any of the experimental groups. Our data suggests that resveratrol has the protective effect on the oxidative stress-induced inhibition of gap junctional intercellular communication in HaCaT keratinocytes, and this protection is likely due to the scavenging of reactive oxygen species.

• 한국대기환경학회지
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• 제13권3호
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• pp.207-214
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• 1997

We collected airborne complex mixtures in a industrial area of Yeochun, and examined whether these complex mixtures could affect gap junctional intercellular communication (GJIC) in a cultured WBF-344 rat liver epithelial cells (LEC). Since the reduction of GJIC plays an important role in chemical carcinogenesis, measurement of changes of GJIC is a meaningful method to screen carcinogenicity of these mixtures. High and low volume samples were dissolved in dimethyl sulfoxide (DMSO) and tested. Blank filter extractions were also examined for exclud-ing possible toxicity of filter itself, and TPA (12-O-tetradecanoylphorbol-13-acetate) and DMSO were used as positive and negative control, respectively. When the cells were exposed to samples at concentration below that required to maintain rather than 85% cell viability based on the result of neutral red uptake assay, maximal inhibition of GJIC was observed at 1hr after treatment with both high and low volume samples by scrape-loading dye transfer assay. In fluorescence recovery after photobleaching assay, recovery rates via gap junctions were 33%/min in high volume sample and 62%/min in low volume sample. In together, airborne samples collected in Yeochun inhibited GJIC in a cultured WBF-344 rat LEC. These results suggest airborne samples tested in this experiment may attribute to cause a certain type and degree of cancers in in vivo when exposured for some periods.

• 한국독성학회:학술대회논문집
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• 한국독성학회 2003년도 추계학술대회
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• pp.123-123
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• 2003

Primary cultures of rat fetus brain exhibit phenotypes of neuron, oligodendrocyte, and astrocyte from "neurospheres". To understand the role of mitogen-activated protein kinase (MAPK) cascade and gap junctional intercellular communication (GJIC) in the differentiation of neurosphere-derived astrocyte, we investigated the effects of 12-O-tetradecanoylphorbol-13-acetate (TPA) on the cultured astrocyte morphology.(omitted)

• 한국식품과학회지
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• 제39권5호
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• pp.558-563
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• 2007

본 연구에서는 정상 세포인 간상피세포를 이용하여 BHT와 PG가 GJIC에 미치는 효과 및 그 작용 기전을 살펴보았다. BHT와 PG를 WB-F344세포에 각각 1.0mM, 0.75mM 이상 처리한 결과, 세포 생육이 80%이하로 저하되어 세포 독성을 보였고, BHT와 PG의 GJIC에 대한 억제효과는 이보다 낮은 농도인 0.6mM, 0.1mM에서 나타났으며 처리에 따른 Cx43 단백질의 발현 및 인산화를 측정한 결과, BHT와 PG 모두 농도의존적으로 Cx43의 인산화가 증가하였고, Cx43의 구조적 변화와 관련된 MAP kinase는 주요 biomarker인 ERK, p38, JNK의 발현 및 인산화를 측정한 결과, 농도의존적으로 ERK와 p38의 인산화가 증가하는 것으로 나타났다. 이는 WB-F344세포에 BHT와 PG의 처리가 세포독성을 나타내기 전 농도에서 GJIC의 억제하였음을 의미하며 이는 식품첨가물의 안전성 평가에도 활용될 수 있을 것으로 기대된다.

• Journal of Ginseng Research
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• 제30권2호
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• pp.64-69
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• 2006

Gap junctional channels, allowing rapid intercellular communication and synchronization of coupled cell activities, play crucial roles in many signaling processes, including a variety of cell activities. Consequently, a modulation of the gap junctional intercellular communication (GJIC) should be a potential pharmacological target. In the present, the GJIC of a epithelial-derived rat mammary cells (BICR-M1Rk) was assessed in the presence of ginseng saponin, by using an established method of scrape-loading dye transfer assay. The transfer of Lucifer yellow (diameter: 1.2 nm) among the neighboring BICR-M1Rk cells, in which connexin43 (Cx43) is a major gap junction channel-forming protein, was significantly retarded at a concentration of $10{\mu}g/ml$ ginseng saponin. By using both methods of RT-PCR and Western blotting, it was demonstrated that ginseng saponin modulated neither the mRNA synthesis of Cx43 nor the translational process of Cx43. This ginseng saponin-induced modification of GJIC was a similar phenomenon observed under the $\beta$-glycyrrhetinic acid treatment, a well-known gap junction channel blocker. Taken together, it is reasonable to conclude that the ginseng saponin inhibits GJIC only by modulating the gating property of gap junction channels.

• 한국식품위생안전성학회지
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• 제16권3호
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• pp.212-220
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• 2001

본 연구는 비수술적 중기 발암성 모델과 gap junction intercellular communication(GJIC)수식을 이용하여 태국에서 회춘약으로 알려진 Pueraria mirfica (Kawo Keur)식물의 항암 및 발암성 유무의 관계를 알아보기 위해 실시했다. 비수술적 중기 발암성 모델 시험의 경우, Pueraria mirifica 식물이 수컷 F344 랫드에 대하여 전암 병변의 발달에 어떠한 영향을 미치는지를 알기 위한 것으로 GST-p양성 병소의 수와 면적을 측정하여 그 수식 효과를 알아보았다. 6주령의 수컷 F344 랫트를 10 개군으로 나누어 간암을 유발하기 위하여 모든 동물에 대하여 시험 시작일에 200 mg/kg의 DEN을 투여하였고, 2주와 5주 말에 각각 300mg/kg의 DGA를 복강 투여하였다. 3군에서 6군까지에 대해서는 sodium phenobarbital을 0.05%의 농도로 음수 투여하였으며, 2군에 대해서는 발암유발 후의 6주 동안 AIN-76A에 10mg/kg의 PM 혼합 사료를, 6군은 시험 전 기간에 걸쳐 8주 동안 10mg/kg의 PM 혼합사료를 급여한 군이다. 또한, 7, 8, 9 및 10군은 2, 4, 5 및 6군과 같은 방법으로 1000mg/kg의 PM을 투여한 군으로 모든 동물은 DEN 투여 후 8주 째에 부검하였다. GST-p 면역염색 결과 양성 병소의 면적과 수에서 10mg/kg의 PM을 투여한 군들은 대조군과 비교시 유의한 차이가 나타나지 않았고, 1000mg/kg의 PM을 투여한 7, 8, 9 및 10군에서도 GST-p 양성 병소의 수와 면적에서 대조군과 비교해 보았을 때 유의한 차이를 관찰할 수 없었다. 또한 PM이 gap junction intercellular communication (GJIC)수식에 어떤 영향을 미치는지를 조사하기 위하여 사람 피부세포에서 SL/DT assay를 실시해 보았으나 이러한 gap junction assay에서도 PM은 GJIC에 영향을 주지 않았다. 이상의 결과를 종합하여 볼 때 Pueraria mirifica는 랫드에서의 실험적 간암 발생과정과 human keratinocyte에 gap junction intercellular communication에서 수식 효과를 가지고 있지 않는 것으로 보아 항암 및 발암성 여부와 관련이 없는 것으로 사료된다.

• 한국독성학회:학술대회논문집
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• 한국독성학회 2005년도 춘계 국제심포지엄 및 학술대회
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• pp.187-187
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• 2005

• 한국환경성돌연변이발암원학회:학술대회논문집
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• 한국환경성돌연변이발암원학회 2003년도 추계학술대회
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• pp.123-123
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• 2003

• Food Science and Biotechnology
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• 제16권5호
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• pp.747-752
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• 2007

This study was carried out to identify and quantify the flavonoids from 6 different plant parts of Allium victorialis var. platyphyllum (AVP), including the flower, leaf, root, stem, flower stalk, and flower seed, using liquid chromatography/ mass spectrometry. Two major flavonoids were structurally identified as quercetin (3,5,7,3'4,'-pentahydroxyflavone) and kaempferol (3,5,7,4'-tetrahydroxyflavone) at contents of 11.8-25.8 and $6.0-64.4\;{\mu}g/mL$, respectively. In particular, the flower and root plant parts contained the highest amounts of quercetin and kaempferol compared to the other parts. We also assessed the recovery effects of each plant-part extract of AVP on gap junctional intercellular communication (GJIC) in WB-F344 cells by the scrape-loading and dye transfer (SL/DT) method. According to the results, GJIC was reduced by approximately 70.2% ($62.3{\pm}12.5$ cells) compared to the control ($209{\pm}9.5$ cells, 100%) when 12-O-tetradecanoylphorbol-13-acetate (TPA) was treated alone in the WB-F344 rat liver epithelial cells. However, the stem extract (0.2 mg/mL) restored GJIC to basal levels (92%, $204{\pm}2.3$ cells, p<0.01) and the flower extract (0.2 mg/mL) stimulated GJIC to 82.5% ($172.6{\pm}8.3$ cells, p<0.05), when applied together with the TPA.