• 한국동물학회지
• /
• 제38권4호
• /
• pp.542-549
• /
• 1995

Extracellular matrix(ECM) 단백질이 SK-N-SH 및 IMR-32 세포주가 신경계 세포로 분화되는 데 미치는 영향을 조사하였다. Laminin과 collagen으로 도말한 배양기에서 7일간 배양했을 때 SK-N-SH세포는 잘 발달된 신경측색생장을 보였으나 IMR-32세포는 뚜렷한 형태변화를 나타내지 않았다. 왜 IMR-32세포가 ECM 단백질에 반응을 하지 않는가를 규명하기 위하여 ECM단백질에 의한 초기 신호전달기작을 두 세포주에서 분석하였다. ECM 단백질을 도말한 배양기에 세포를 깔았을 때 한시간 만에 tyrosine 인산화된 단백질이 두 세포 모두 증가함을 볼 수 있었다. 아울러 focal adhesion kinase(FAK)의 tyrosine 인산화도 두 세포주 모두에서 증가하였다. 이러한 결과는 두 세포주가 ECM 단백질에 의한 초기 신호전달체계가 정상임을 의미한다. 신경세포 분화과정에 증가한다고 알려진 Bcl-2 및 NSE의 량을 ECM 단백질 처리후 조사하였을 때 SK-N-SH 세포주는 두 단백질이 증가 했지만 IMR-32 세포주는 변화가 없었다. 이러한 결과는 IMR-32 세포주가 ECM 단백질에 반응하지 않는 것이 ECM 단백질에 의한 신호전달체계에 문제가 있다기 보다 신경계세포로 분화되는 데 필요한 유전인자의 발현조절에 문제가 있음을 시사한다.

• Biomolecules & Therapeutics
• /
• 제14권3호
• /
• pp.137-142
• /
• 2006

Apigenin, a natural flavonoid found in a variety of vegetables and fruits, has been shown to possess many biological functions. In this study we investigated the role of apigenin in the production of reactive oxygen species (ROS) through the modulation of activity of $K^+-Cl^-$-cotransport (KCC) in IMR-32 human neuroblastoma cells. Apigenin induced $Cl^-$-dependent $K^+$ efflux, a hallmark of KCC activity, which was markedly prevented by different kinds of KCC inhibitors (calyculin-A, genistein and $BaCl_2$). These results indicate that KCC is functionally present, and activated by apigenin in the IMR-32 cells. Treatment with apigenin also induced a sustained increase in the level of intracellular ROS. The KCC inhibitors also significantly inhibited the apigenin-induced ROS generation. Taken together, these results suggest that apigenin can modulate ROS generation through the activation of a membrane ion transporter, KCC. These results further suggest that the alteration of KCC activity may play a role in the mechanism of degenerative diseases and/or carcinogenesis in neuronal tissues through the regulation of ROS production.

• 대한의생명과학회지
• /
• 제3권1호
• /
• pp.11-20
• /
• 1997

신경아세포종 세포 분화의 조절에 대한 연구는 아직 초기 단계에 불과하나 신경아세포종양의 임상적인 치료에 매우 중요한 기초가 된다. 본 연구는 신경아세포종 세포의 분화를 유도 할 수 있는 유용한 시약을 찾아내고자 하는 노력의 일환으로, 잘 알려진 DNA 합성 억제제가 신경 아세포종의 분화를 유도할 수 있는지를 살펴보고자 신경아세포종양 세포의 형태적, 생화학적 및 유전자 발현에 미치는 효과를 살펴보았다. 신경아세포종양으로부터 수립된 세포주, IMR-32 세포에 DNA 합성 억제제인 sodium butyrate, hydroxyurea, cytosine arabinoside를 각각 처리한 결과 처리하지 않은 대조군과는 달리 정상신경 세포 분화시 볼 수 있는 신경 돌기의 성장이 유도됨을 관찰할 수 있었으며 ,신경 전달 물질인 acetylcholine의 합성 효소인 choline acetyltransferase의 활성도가 현저히 증가되었다. 또한DNA합성 억제제를 처리하지 않은 IMR-32세포에서 탐지되지 않았던 c-myc 유전자의 발현이 시약 처리시 확연히 탐지됨을 관찰할 수 있었다. 이러한 실험 결과들은 DNA합성 억제제가 IMR-32세포의 성장을 억제하고 분화를 유도했음을 보여준 것이며, 어린 아이 시기에 많이 발병되는 신경아세포종양의 급속한 악성화나 전이의 억제기전을 제시해 줄 수 있으리라 생각한다.

• Animal cells and systems
• /
• 제9권4호
• /
• pp.191-198
• /
• 2005

The effects of 6-aminonicotinamide (6-AN) on viability of IMR32 neuroblastoma cells in the presence of ATP or $NAD^+$ have been investigated. 6-AN caused marked reduction in cell viability and similar observations were also made with cells treated with 6-AN+ATP. However, cells treated with $6-AN+NAD^+$ showed cell viability similar to untreated cells. Morphologically, 6-AN and 6-AN+ATP treated cells showed loss of neurites, polyhedric shapes, shrinkage of cell bodies and formation of lysed cells, while $6-AN+NAD^+$ cells did not show any such changes. The flow cytometry analysis demonstrated that 6-AN increased cell population in $G_0/G_1$ phase and decreased cell population in Sand $G_2/M$ phase following a 72 h exposure. Western blot analysis showed that 6-AN stimulated a substantial increase in the level of the cdk inhibitor $p27^{kip1}$, but lowered the levels of cdk2, cyclin E and p-Rb. However, cdc25A and p53R2 were not significantly affected. Immunofluorscence staining of $p27^{kip1}$, cdk2, cyclin E and p-Rb revealed close correlation between the signal observed in the Western blot analysis. 6AN+ATP treated cells showed similar results obtained with 6-AN treated cells in expression of cdk2, cyclin E, p-Rb proteins and $p27^{kip1}$, $6-AN+NAD^+$ cells showed greater expression of cdk2, cyclin E and p-Rb than those in 6-AN and 6-AN+ATP treated cells. The results suggest that 6-AN induced the $G_0/G_1$ phase arrest in IMR32 neuroblastoma cell lines through the increase of $p27^{kip1}$ and the decrease of cdk2, cyclin E and p-Rb.

• Journal of Genetic Medicine
• /
• 제1권1호
• /
• pp.45-50
• /
• 1997

Neuroblastoma, a pediatric malignant neoplasm of neural crest origin, has a wide range of clinical virulence. The mechanisms contributing to the development of neuroblastomas are largely unclear, but non-random chromosomal changes identified over the past years suggest the involvement of genetic alterations. Amplification of the human N-myc proto-oncogene is frequently seen either in extrachromosomal double minutes or in homogeneously staining regions (HSRs) of aggressively growing neuroblastomas. N-myc maps to chromosome 2 band 24, but HSR have never been observed at this band, suggesting transposition of N-myc during amplification. We have constructed and analyzed the region-specific painting probe for HSR in neuroblastoma IMR-32 to determine the derivative chromosomes. Microdissection was performed on HSR using an inverted microscope with the help of microglass needles and an micromanipulator. We pretreated the microdissected fragments with Topoisomerase I which catalyzes the relaxation of supercolled DNA, and performed two initial rounds of DNA synthesis with T7 DNA polymerase followed by conventional PCR to enable the reliable preparation of Fluorescent in situ hybridization probe from a single microdissected chromosome. With this method, it was possible to construct the region-specific painting probe for HSR. The probe hybridized specifically to the HSRs of IMR-32, and to 2p24, 2p13 of normal chromosome. Our results suggest there was coamplification of N-myc together with DNA of the chromosome 2p24 and 2p13. Moreover, the fluorescent signals for the amplified chromosomal regions in IMR-32 cells were also easily recognized at a Thus this painting probe can be applied to detect the similar amplification of N-myc in neuroblastoma tissue, and the probe pool for HSR may be used to identify the cancer-relevant genes.

• The Korean Journal of Physiology and Pharmacology
• /
• 제3권1호
• /
• pp.19-27
• /
• 1999

Apoptosis has been implicated in the pathophysiological mechanisms of various neurodegenerative diseases. In a variety of cell types, oxidative stress has been demonstrated to play an important role in the apoptotic cell death. However, the exact mechanism of oxidative stress-induced apoptosis in neuronal cells is not known. In this study, we induced oxidative stress in IMR-32 human neuroblastoma cells with tert- butylhydroperoxide (TBHP), which was confirmed by significantly reduced glutathione content and glutathione reductase activity, and increased glutathione peroxidase activity. TBHP induced decrease in cell viability and increase in DNA fragmentation, a hallmark of apoptosis, in a dose-dependent manner. TBHP also induced a sustained increase in intracellular $Ca^{2+}$ concentration, which was completely prevented either by EGTA, an extracellular $Ca^{2+}$ chelator or by flufenamic acid (FA), a non-selective cation channel (NSCC) blocker. These results indicate that the TBHP-induced intracellular $Ca^{2+}$ increase may be due to $Ca^{2+}$ influx through the activation of NSCCs. In addition, treatment with either an intracellular $Ca^{2+}$ chelator (BAPTA/AM) or FA significantly suppressed the TBHP-induced apoptosis. Moreover, TBHP increased the expression of p53 gene but decreased c-myc gene expression. Taken together, these results suggest that the oxidative stress-induced apoptosis in neuronal cells may be mediated through the activation of intracellular $Ca^{2+}$ signals and altered expression of p53 and c-myc.

• Archives of Pharmacal Research
• /
• 제22권4호
• /
• pp.404-409
• /
• 1999

The inhibitory effects of the constituents of Gastrodia elata Bl. (GE) on glutamate-induced apoptosis in human neuronal cells were investigated using IMR32 human neuroblastoma cells. Glutamate (GLU) induced DNA fragmentation, a hallmark of apoptosis, in a dose-dependent manner. GLU also induced a slow and sustained increase in intracellular $Ca^{2+}$ concentration. Treatment with EGTA, an extracellular $Ca^{2+}$ chelator, in a nominal $Ca^{2+}$ -free buffer solution abolished the GLU-induced intracellular $Ca^{2+}$ increase, indicating that GLU stimulated Ca2+ influx pathway in the IMR32 cells. BAPTA, an intracellualr $Ca^{2+}$ chelator, significantly inhibited the GLU-induced apoptosis assessed by the flow cytometry measuring hypodiploid DNA content indicative of apoptosis, implying that intracellular $Ca^{2+}$ rise may mediate the apoptotic action of GLU. Vanillin (VAN) and p-hydroxybenzaldehyde(p-HB), known constituents of GE, significantly inhibited both intracellular $Ca^{2+}$ rise and apoptosis induced by GLU. These results suggest that the apoptosis-inhibitory actions of the constituents of GE may account, at least in part, for the basis of their antiepileptic activities. These results further suggest that intracelluarl $Ca^{2+}$ signaling pathway may be a molecular target of the constituents of GE.

• Bulletin of the Korean Chemical Society
• /
• 제32권1호
• /
• pp.53-58
• /
• 2011

Cysteine and histidine-capped water-dispersible ZnS:Mn nanocrystals (ZnS:Mn-Cys and ZnS:Mn-His) were synthesized and their effects on E. coli and human cells were investigated. Particle sizes of these nanocrystals were found from HR-TEM images to be 3.5 nm and 4.0 nm, respectively. Their solution photoluminescence spectra showed identical broad emission peaks at 580 nm. ZnS:Mn-His significantly suppressed the growth of E. coli at $100{\mu}g/mL$ and 1 mg/mL concentrations, something not observed with ZnS:Mn-Cys. Consistent with this, greater inhibition of cell proliferation and viability were observed in HEK293 and IMR90 cells in ZnS:Mn-His at $100{\mu}g/mL$ and 1 mg/mL concentrations.

• Nutrition Research and Practice
• /
• 제4권6호
• /
• pp.455-461
• /
• 2010

The tumor microenvironment, particularly sufficient nutrition and oxygen supply, is important for tumor cell survival. Nutrition deprivation causes cancer cell death. Since apoptosis is a major mechanism of neuronal loss, we explored neuronal apoptosis in various microenvironment conditions employing neuroblastoma (NB) cells. To investigate the effects of tumor malignancy and differentiation on apoptosis, the cells were exposed to poor microenvironments characterized as serum-free, low-glucose, and hypoxia. Incubation of the cells in serum-free and low-glucose environments significantly increased apoptosis in less malignant and more differentiated N-type IMR32 cells, whereas more malignant and less differentiated I-type BE(2)C cells were not affected by those treatments. In contrast, hypoxia (1 % $O_2$) did not affect apoptosis despite cell malignancy. It is suggested that DLK1 constitutes an important stem cell pathway for regulating self-renewal, clonogenicity, and tumorigenicity. This raises questions about the role of DLK1 in the cellular resistance of cancer cells under poor microenvironments, which cancer cells normally encounter. In the present study, DLK1 overexpression resulted in marked protection from apoptosis induced by nutrient deprivation. This in vitro model demonstrated that increasing severity of nutrition deprivation and knock-down of DLK1 caused greater apoptotic death, which could be a useful strategy for targeted therapies in fighting NB as well as for evaluating how nutrient deprived cells respond to therapeutic manipulation.

• 생약학회지
• /
• 제38권4호
• /
• pp.308-311
• /
• 2007

Inhibition of acetylcholinesterase and amyloid beta(1-42) peptide is good drug targets for Alzheimer's disease therapeutics. Among the twenty enthusiasm reducing herbals, the 70% methanol extracts (1 mg/ml) of Moutan Radicis Cortex and Forsythiae Fructus showed 91.5% and 85.3% about acethylcholinesterase inhibition, respectively. The extracts (1 mg/ml) of Coptidis Rhizoma and Paeoniae Radix Rubra showed more than 85% inhibition rate against amyloid beta (1-42) peptide aggregation. The neuroprotective effect of the extracts (1 mg/ml) of Moutan Radicis Cortex, Forsythiae Fructus and Paeoniae Radix Rubra showed 90.0%, 87.4% and 85.1% to compare with amyloid beta (1-42) peptide treated cells (IMR-32), respectively. Three herbs, Moutan Radicis Cortex, Forsythiae Fructus and Paeoniae Radix Rubra are promising candidates from natural products for development of Alzheimer's disease therapeutics.