• Biomolecules & Therapeutics
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• v.19 no.2
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• pp.174-180
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• 2011

Experiments were carried out to determine the role of Raf-1 kinase in the development of drug resistance to paclitaxel in v-H-ras transformed NIH 3T3 fibroblasts (Ras-NIH 3T3). We established a multidrug-resistant cell line (Ras-NIH 3T3/Mdr) from Ras-NIH 3T3 cells by stepwise increases in paclitaxel. Drug sensitivity assays indicated that the $IC_{50}$ value for drug-resistant Ras-NIH 3T3/Mdr cells was more than 1 ${\mu}M$ paclitaxel, 10- or more-fold higher than for the parental Ras-NIH 3T3 cells. Western blot and RT-PCR analysis showed that the drug efflux pump a P-glycoprotein were highly expressed in Ras-NIH 3T3/Mdr cells, while not being detectable in Ras-NIH 3T3 cells. Additionally, verapamil, which appears to inhibit drug efflux by acting as a substrate for P-glycoprotein, completely reversed resistance to paclitaxel in Ras-NIH 3T3/Mdr cell line, indicating that resistance to paclitaxel is associated with overexpression of the multidrug resistance gene. Interestingly, Ras-NIH 3T3/Mdr cells have higher basal Raf-1 activity compared to Ras-NIH 3T3 cells. Unexpectedly, however, the colocalization of Raf-1 and its negative regulator Spry2 was less observed in cytoplasm of Ras-NIH 3T3/Mdr cells due to translocation of Spry2 around the nucleus in the perinuclear zone, implying that Raf-1 may be released from negative feedback inhibition by interacting with Spry2. We also showed that shRNA-mediated knockdown of Raf-1 caused a moderate increase in cell susceptibility to paclitaxel. Thus, the results presented here suggest that a Raf-1-dependent pathway plays an important role in the development of acquired drug-resistance.

• Journal of Life Science
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• v.17 no.3 s.83
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• pp.375-380
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• 2007

Dynamin plays a key role in the scission event common to various types of endocytosis. It has been previously reported that the SH3 domain-mediated association of Grb2 with dynamin-2 was dominantly found in Ras transformed cells. However, whether this association results from the increased expression of dynamin-2 and Grb2 in Ras transformed cells or not is still unknown. So in this study we first analyzed the expression levels of dynamin-2 and Grb2 and found that the expression of dynamin-2 protein was dramatically increased in Ras-transformed NIH3T3 (NIH3T3(Ras)) cells. Furthermore competitive PCR data revealed that the mRNA transcripts for dynamin-2 were increased about 100-fold in NIH3T3(Ras) compared to those of NIH3T3 cells. However, the protein level and mRNA transcript of Grb2 were not changed in these two cells. We also examined promoter activity of dynamin-2 in NIH3T3(Ras) cells and suggest the existence of Ras-responsive sequence in promoter region -300 to -200.

• Korean Journal of Microbiology
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• v.27 no.1
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• pp.10-15
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• 1989

The plasmid pKOneo, containing SV40 transcriptional promoter, has been used in the mouse tumorigenicity assay for oncogene studies. This assay employs a cotransfection of NIG3T3 fibroblast cells with the desired DNA and the plasmid pKOneo. This oncogene assay, however, has been speculated due to the SV40 transcriptional promoter in the plasmid pKOneo. This research was designed to investigate if the plasmid pKOneo alone is capable of transforming NiH3T3 fibroblast cells. The NIH3T3 subclones were established after the NIH3T3 cells were transfected with the plasmid pKOneo alone. The estabilished NIH3T3 subclones, containing the exogeneous plasmid pKOneo in their chromosomes, were examined for their expression of transformation-associated parameters. The results indicate that this plasmid pKOneo alone has positive effects on transformation of NIH3T3 cells after integration into cellular chromosomes.

• Applied Microscopy
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• v.35 no.3
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• pp.121-128
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• 2005

It has been known that ras signaling transduction leads to cell proliferation and migration including various adaptor molecules. Dynamin protein has been implicated in the formation of nascent vesicles in both the endocytic and secretory pathways. Dynamin was classified into three isoforms: dynamin I is only expressed in neuronal tissue, dynamin II is expressed ubiquitously in all tissue but that of dynamin III is confined to testis. We have reported in previous study that Grb2, binding to ras, was associated with dynamin II in NIH3T3 cells. Therefore we have tried to identify the relative expression of dynamin II according to overexpressed ras protein in ras oncogene transfected cells (NIH3T3 (ras)). For the detection of differential expression of dynamin II, we have used immunofluorescent staining and western blot methods in NIH3T3 and NIH3T3 (ras) cells. Next we have described the morphological differences between NIH3T3 and NIH3T3 (ras) cells using SEM and TEM. From these experiments dynamin II was highly expressed in NIH3T3 (ras) cells. NIH3T3 cells was transformed to more spindle shape with many cell process by transfection of ras oncogene. Moreover dynamin II was more concentrated in endocytotic membrane of the NIH3T3 (ras) cells compared to that of NIH3T3 cells. The present results suggested that dynamin II may involve the intermediate messenger in Ras signaling transduction pathway.

• Biomolecules & Therapeutics
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• v.20 no.4
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• pp.393-398
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• 2012

Recently, we reported that defective autophagy may contribute to the inhibition of the growth in response to PP2 (4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine), a selective SFK inhibitor, in multidrug-resistant v-Ha-ras-transformed NIH 3T3 cells (Ras-NIH 3T3/Mdr). In this study, we demonstrated that PP2 induces LC3 conversion via a mechanism that is uncoupled from autophagy and increases apoptosis in Ras-NIH 3T3/Mdr cells. PP2 preferentially induced autophagy in Ras-NIH 3T3 cells rather than in Ras-NIH 3T3/Mdr cells as determined by LC3-I to LC3-II conversion and GFP-LC3 fluorescence microscopy. Beclin 1 knockdown experiments showed that, regardless of drug resistance, PP2 induces autophagy via a Beclin 1-dependent mechanism. PP2 induced a conformational change in Beclin 1, resulting in the enhancement of the pro-autophagic activity of Beclin 1, in Ras-NIH 3T3 cells. Further, PI3K inhibition induced by wortmannin caused a significant increase in apoptosis in Ras-NIH 3T3 cells, as demonstrated by flow cytometric analysis of Annexin V staining, implying that autophagy inhibition through PI3K increases apoptosis in response to PP2 in Ras-NIH 3T3 cells. However, despite the fact that wortmannin abrogates PP2-induced GFP-LC3 punctae formation, some LC3 conversion remains in Ras-NIH 3T3/Mdr cells, suggesting that LC3 conversion may occur in an autophagy-independent manner. Taken together, these results suggest that PP2 induces LC3 conversion independent of PI3K, concomitant with the uncoupling of LC3 conversion from autophagy, in multidrug-resistant cells.

• Restorative Dentistry and Endodontics
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• v.28 no.5
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• pp.419-424
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• 2003

이 연구의 목적은 원래의 치수조직과 유사한 조직을 재생하기 위한 pulp tissue engineering의 한 방법으로 건전한 조직으로부터 배양된 치수세포와 쥐의 조섬유세포(NIH 3T3 cell)를 Rat tail type I collagen solution에서 3차원적으로 관찰하기 위한 것으로, 콜라젠 젤의 수축량과 세포의 증식 량을 비교하였으며, 또한 마모된 사람치아의 표면과 배양용기에서 두 세포의 증식 량을 비교하여 다음과 같은 결과를 얻었다. 1. 콜라젠 젤에 NIH 3T3 세포를 배양한 경우 그 수축량은 최소였으나, 치수세포를 배양한 경우 그 수축량은 현저하였다. 2. 서로 다른 수의 치수세포를 콜라젠 젤에서 배양시킨 경우 세포 수가 많을수록 수축량이 증가하였으며, 세포가 없는 콜라젠 젤은 수축하지 않았다. 3. 치수세포를 콜라젠 젤에서 18일간 배양시킨 후 세포의 증식은 거의 없는 반면, NIH 3T3 세포는 계속 증식하였다. 4. 마모된 사람 치아 표면과 배양 용기에서 치수세포와 NIH 3T3세포를 배양한 경우 NIH 3T3세포가 치수세포에 비해 빠르게 증식 하였으며 , 특히 사람 치아의 표면에서 NIH 3T3세포가 현저히 빠른 증식을 보였다. 이상의 결과는 치수세포를 type I collagen gel에서 3차원 적으로 배양 후 치수조직의 재생을 유도하는 pulp tissue engineering에 관한 연구에 발판이 될 것으로 사료된다.

• The Korea Journal of Herbology
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• v.21 no.4
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• pp.143-148
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• 2006

Objectives : It is demonstrated that oxygen free radicals have cytotoxic effect on NIH3T3 fibroblast cells. Recently, many of herb extracts have an effect of antioxidant in oxygen free radical-induced cytotoxicity. But, the toxic mechanism of oxygen free radical is left unknown. The purpose of this study was to examine the cytotoxicity of hydrogen peroxide ($H_2O_2$) and antioxidant effect of Citri reticulatae pericarpium (CRP) on NIH3T3 fibroblasts. Methods : The cytotoxicy was measured by cell viability by XTT assay in NIH3T3 fibroblasts. XTT assay is regarded as a very sensitive screening method for the determination of the cell viability on various chemicals. Results : In this study, H2O2 decreased cell viability according to the dose- and time dependent manners after NIH3T3 fibroblasts were treated with various concentrations of H2O2 for 4 hours. And also, CRP showed the effect of antioxidant on $H_2O_2-induced $ cytotoxicity in cultured NIH3T3 fibroblasts. Conclusion : These results suggest that $H_2O_2$ has highly cytotoxic effect on cultured NIH3T3 fibroblasts by the decrease of cell viavility, and the herb extract such as CRP was showed the effect of antioxidant on $H_2O_2-induced$ cytotoxicity in these cultures.

• Journal of Life Science
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• v.12 no.2
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• pp.182-187
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• 2002

In this study we have investigated the effect of Caesalpina sappann L. extracts on the apoptosis in NIH3T3 cells exposed to methylmethan sulfonate (MMS), an alkylating agent. MTT assay study showed that Caesalpina sappan L. extracts potentiate the MMS-induced viability. Cell morphology studies, acridine orange (AO) staining, and DNA fragmentation analysis indicated that the postincubation of Caesalpina sappan L. extracts increase the nuclear condensation of MMS-induced apoptotosis. These results suggest that Caesalpina sampan L. extracts contain components potentiating MMS-induced apoptosis of NIH3T3 cells.

• Toxicological Research
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• v.16 no.2
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• pp.173-178
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• 2000

This study was carried out to investigate cytotoxicity of several herbicides (Bentazone, Butachlor. Paraquat and Ethalfluralin) in cultured mouse NIH 3T3 fibroblasts. Tetrazolium (MTT), neutral red (NR) and sulforhodamine protein B (SRB) of the colorimetric assays were performed to evaluate the cytotoxicity on cell organelles. 2 x 10$^4$cell/$m\ell$ of NIH 3T3 fibroblast in each well of 24 multidish were cultured. After 24 hours, the cells were treated with solution (1, 25, 50 or 100 $\mu$M) of each herbicide. After the NIH 3T3 fibroblasts of all groups were cultured in the same condition for 48 hours, MTT, NR and SRB assays were performed to evaluate the cytotoxicity. The light microscopic study was carried out to examine morphological changes of cultured NIH 3T3 fibroblasts. The MTT$_{50}$ of Bentazone, Butachlor, Paraquat and Ethalfluralin were 1560.97 $\mu$M, 56.15 $\mu$M, 3138.81 $\mu$M and 1301.82 $\mu$M, respectively. The NR$_{50}$ of Bentazone, Butachlor. Paraquat and Ethalfluralin were 1763.93 $\mu$M, 45.98 $\mu$M, 1030.85 $\mu$M and 1808.29 $\mu$M, respectively. The SRB$_{50}$ of Bentazone, Butachlor. Paraquat and Ethalfluralin were 1913.38 $\mu$M, 65.30 $\mu$M, 1860.73 $\mu$M and 1086.93 $\mu$M, respectively. The morphological changes of NIH 3T3 fibroblasts showed severe degeneration in Butachlor 50 $\mu$M and 100 $\mu$M concentrations. These results indicate that Butachlor has high cytotoxicity, Bentazone, Paraquat and Ethalfluralin very weak cytotoxicity against NIH 3T3 fibroblasts.lasts.

• Biomedical Science Letters
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• v.14 no.3
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• pp.187-192
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• 2008

To clerify the protective effect of omega-3 of polyunsaturated fatty acid docosahexaenoic acid (DHA) on the cytotoxicity induced by organic mercury in cultured NIH3T3 fibroblasts. The measurement of cell viability on ogranic mercury wad done by XTT assay after NIH3T3 fibroblasts were cultured with various concentrations of methyl mercuric chloride (MMC). And also, the effect of DHA on the MMC-mediated cytotoxicity was examined by cell viability, and antioxidant effect of DHA was also assessed by superoxide dismutase (SOD)-like activity and the lipid peroxidation activity in cultured NIH3T3 fibroblasts. In this study, MMC decreased cell viability and $XTT_{50}$ value was determined at $50{\mu}M$ of MMC in these culture. In the effect of DHA against the cytotoxicity induced by MMC, DHA significantly increased the cell viability damaged by MMC in cultured NIH3T3 fibroblasts. And also, DHA showed the antioxidant effect by showing the increase of SOD-like activity and the decrease of lipid peroxidation activity. From these results, it is suggested that organic mercury such as MMC has highly toxic effect on cultured NIH3T3 fibroblasts, and also, omega-3 of polyunsaturated fatty acid, DHA showed the protection on MMC-induced cytotoxicity and antioxidant effect.