• Journal of Pharmaceutical Investigation
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• v.34 no.5
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• pp.393-399
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• 2004

For the efficient determination of activity against solid tumors, an in vitro tumor model that resembles the condition of in vivo solid tumors, is required. The purpose of this study was to establish a rapid culture method and viability assay for an in vitro 3-dimensional tumor model, multicellular spheroid (MCS). Among 12 human cancer cell lines, a few cell lines including DLD-1 (human colorectal carcinoma cells) formed fully compact MCS which was adequate for in vitro viability assay. DLD-1 MCS showed steady growth reaching $700\;{\mu}m$ diameter after 11 day culture. DLD-1 cells grown as MCS showed significant increase in $G_0/G_1$ phase compared to the monolayer cells (73.9% vs 45.7%), but necrotic regions or apoptotic cells were not observed. The cells cultured as MCS showed resistance to 5-FU (10.3 fold higher $IC_{50}$) compared to monolayers, however, tirapazamine (a hypotoxin) showed similar activity in both culture systems. In summary, MCS may be a valid in vitro model for activity screening of anticancer agents against human solid tumors and also exploitable for studying molecular markers of drug resistance in human solid tumors.

• Journal of Veterinary Science
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• v.22 no.3
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• pp.25.1-25.16
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• 2021

Background: Malignant lymphoma is the most common hematopoietic malignancy in dogs, and relapse is frequently seen despite aggressive initial treatment. In order for the treatment of these recurrent lymphomas in dogs to be effective, it is important to choose a personalized and sensitive anticancer agent. To provide a reliable tool for drug development and for personalized cancer therapy, it is critical to maintain key characteristics of the original tumor. Objectives: In this study, we established a model of hybrid tumor/stromal spheroids and investigated the association between canine lymphoma cell line (GL-1) and canine lymph node (LN)-derived stromal cells (SCs). Methods: A hybrid spheroid model consisting of GL-1 cells and LN-derived SC was created using ultra low attachment plate. The relationship between SCs and tumor cells (TCs) was investigated using a coculture system. Results: TCs cocultured with SCs were found to have significantly upregulated multidrug resistance genes, such as P-qp, MRP1, and BCRP, compared with TC monocultures. Additionally, it was revealed that coculture with SCs reduced doxorubicin-induced apoptosis and G2/M cell cycle arrest of GL-1 cells. Conclusions: SCs upregulated multidrug resistance genes in TCs and influenced apoptosis and the cell cycle of TCs in the presence of anticancer drugs. This study revealed that understanding the interaction between the tumor microenvironment and TCs is essential in designing experimental approaches to personalized medicine and to predict the effect of drugs.

• Journal of Korean Neurosurgical Society
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• v.30 no.3
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• pp.263-271
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• 2001

Objective : Glioblastomas, the most common type of primary brain tumors, are highly invasive and cause massive tissue destruction at both the tumor invading edges and in areas that are not in direct contact with glioma cells. As a result, patients with high-grade gliomas are faced with a poor prognosis. Such grim statistics emphasize the need to better understand the mechanisms that underlie glioma invasion, as these may lead to the identification of novel targets in the therapy of high grade gliomas. Protein kinase C(PKC) is a family of serine/threonine kinases and an important signal transduction enzyme that conveys signals generated by ligand-receptor interaction at the cell surface to the nucleus. PKC appears to be critical in regulating many aspects of glioma biology. The purpose of this study was to assess accurately the role of PKC in the invasion regulation of human gliomas based on hypothesis that protein kinase C(PKC) is functional in the process of glial tumor cell invasion. Method : To test this hypothesis, U-87 malignant glioma cell line intracellular PKC levels were up and down regulated and their invasiveness was tested. Intracellular PKC level was characterized using PKC activity assays. Invasion assays including barrier migration and spheroid confrontation were used to study the relationship between PKC concentration and invasiveness. Result : The cell line which were treated by PKC inhibitor tamoxifen and hypericin exhibited decreased PKC activity and decreased invasive abilities dose dependently both in matrigel invasion assay and tumor spheroid fetal rat brain aggregates(FRBA) confrontation assay. However, the cell line that was treated by PKC activator 12-O-tetradecanylphorbol-13acetate(TPA) did not exhibit increases in either PKC activity or invasive ability. Conclusion : These studies suggest that PKC may be a useful molecular target for the chemotherapy of glioblastoma and other malignancies and that a therapeutic approach based on the ability of PKC inhibitors may be helpful in preventing invasion.

• Journal of Life Science
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• v.34 no.7
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• pp.476-484
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• 2024

Although two-dimensional (2D) monolayer cell culture models are still widely used as the optimal models for anticancer activity research, three-dimensional (3D) multicellular tumor spheroid (3D MTS) models that can better approximate the tumor environment can offer an alternative to bridge the gap between in vitro and animal model studies. Isoalantolactone is among the sesquiterpene lactones found in medicinal plants, including the roots of Elecampane (Inula helenium L.), and is known to have various pharmacological activities, including anticancer activity. In this study, we investigated whether the anticancer activity of isoalantolactone observed in 2D models could be reproduced in a 3D MTS model derived from human hepatocellular carcinoma (HCC) Hep3B cells. According to our results, isoalantolactone inhibited the formation of MTSs in a manner dependent on the treatment concentration, which was accompanied by an increase in reactive oxygen species (ROS) generation. In particular, as isoalantolactone treatment and the culture time increased, the area of proliferating cells was replaced by cells in which apoptosis was induced. Additionally, in MTSs, isoalantolactone increased the expression of death-receptor-related proteins and the activity of caspase-3, and it decreased the expression of the Bax/Bcl-2 expression ratio and total poly(ADP-ribose) polymerase. However, when the production of ROS was artificially blocked, all these changes caused by isoalantolactone were attenuated and the cell survival rate of MTS cells was restored. Therefore, the results of this study suggest that the induction of apoptosis in Hep3B cell-derived MTSs by isoalantolactone is achieved through the activation of extrinsic and intrinsic pathways and is ROS-dependent.

• Molecules and Cells
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• v.40 no.5
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• pp.322-330
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• 2017

This study investigated the role of cancer/testis antigen DDX53 in regulating cancer stem cell-like properties. DDX53 shows co-expression with CD133, a marker for cancer stem cells. DDX53 directly regulates the SOX-2 expression in anti-cancer drug-resistant $Malme3M^R$ cells. DDX53 and miR-200b were found to be involved in the regulation of tumor spheroid forming potential of Malme3M and $Malme3M^R$ cells. Furthermore, the self-renewal activity and the tumorigenic potential of $Malme3M^R$-CD133 (+) cells were also regulated by DDX53. A miR-200b inhibitor induced the direct regulation of SOX-2 by DDX53 We therefore, conclude that DDX53 may serve as an immunotherapeutic target for regulating cancer stem-like properties of melanomas.

• BMB Reports
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• v.56 no.7
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• pp.410-415
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• 2023

Breast cancer has become the most common cancer among women worldwide. Among breast cancers, metastatic breast cancer is associated with the highest mortality rate. Twist1, one of the epithelial-mesenchymal transition-regulating transcription factors, is known to promote the intravasation of breast cancer cells into metastatic sites. Therefore, targeting Twist1 to develop anti-cancer drugs might be a valuable strategy. In this study, LY-290181 dose-dependently inhibited migration, invasion, and multicellular tumor spheroid invasion in breast cancer cell lines. These anti-cancer effects of LY-290181 were mediated through the down-regulation of Twist1 protein levels. LY-290181 inhibited extracellular signal-regulated kinase and c-Jun N-terminal kinase signaling pathways. Therefore, our findings suggest that LY-290181 may serve as a basis for future research and development of an anti-cancer agent targeting metastatic cancers.

• Journal of Life Science
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• v.26 no.11
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• pp.1313-1319
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• 2016

Cancer is a complex disease heterogeneously composed of various types of cells including cancer stem-like cells responsible for relapse and chemoresistance in the tumor microenvironment. The conventional two-dimensional cell culture-based platform has critical limitations for representing the heterogeneity of cancer cells in the three-dimensional tumor niche in vivo. To overcome this insufficiency, three-dimensional cell culture methods in a scaffold-dependent or -free physical environment have been developed. In this study, we improved and simplified the HCT-8 colon cancer cell-based spheroid culture protocol and evaluated the relationship between cancer stemness and responses of chemosensitivity to 5- Fluorouracil (5-FU), a representative anticancer agent against colon cancer. Supplementation with defined growth factors in the medium and the culture dish of the regular surface with low attachment were required for the formation of constant-sized spheroids containing $CD44^+$ and $CD133^+$ colon cancer stem cells. The chemo-sensitivities of $CD44^+$ cancer stem cells in the spheroids were much lower than those of $CD44^-$ non-stem-like cancer cells, indicating that the chemoresistance to 5-FU is due to the stemness of colon cancer cells. Taken together, the inflammation and oncogenic gut environment-sensitive HCT-8 cell-based colon cancer spheroid culture and comparative evaluation using the simplified model would be an efficient and applicable way to estimate colon cancer stemness and pharmaceutical response to anticancer drugs in the realistic tumor niche.

• Journal of Life Science
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• v.21 no.7
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• pp.953-960
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• 2011

Necrosis is characterized by the cell membrane rupture and release of the cellular contents, including high-mobility group box 1 protein (HMGB1), into the extracellular microenvironment. HMGB1 acts as a transcriptional regulator in nuclei, but exerts a pro-inflammatory and tumor-promoting cytokine activity when released into the extracellular space. Its overexpression is associated with tumor progression and chemoresistance. Thus, HMGB1 acts as a clinically important molecule in tumor biology. In this study, we examined whether HMGB1 affects cell death induced by anti-cancer drugs. Here we show that HMGB1 prevented cisplatin (alkylating agent)-induced apoptosis and switched the cell fate to necrosis in MCF-7, MDA-MB231, and MDA-MB361 cells. Similar apoptosis-to-necrosis switch effects of HMGB1 were observed in cells treated with 4-HC, another alkylating agent. In contrast, HMGB1 did not exert any significant effects on docetaxel (DOC)-induced apoptosis in MCF-7 cells. We also show that cisplatin-induced apoptosis was switched to necrosis in MCF-7 multicellular tumor spheroids (MTS) that were cultured for 8 days and had necrotic cores, but DOC-induced apoptosis was prevented without the apoptosis-to-necrosis switch. Finally, the levels of RAGE, a receptor of HMGB1, were increased with extended culture of MTS. These findings demonstrate that HMGB1 switches alkylating agent-induced apoptosis to necrosis, suggesting that the strategy to prevent necrosis occurring as an undesirable action of alkylating agent-based chemotherapy should be delineated to improve the efficacy of chemotherapy for cancer.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.129-130
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• 1994

The science of toxicology is the understanding of the mechanisms by which exogenous agents produce deleterious effects in biological systems. The actions of chemicals such as drugs are ultimately exerted at the cellular and gene levels. Over the past decade. several in vitro alternative methods such as cultured cells for assessing the toxicity of various xenobiotics have been proposed to reduce the use of animals. In this workshop three advanced methods will be presented. These methods are novel important models for toxicologic studies. Dr. Tabuchis group has establishcd two immortalized gastric surface mucosa cell lines from the pminary cultore of gastric fundic mucosal cells of adult transgenic mice harboring a temperature sensitive simian virus 40 large T-anugen gene. As the immortalized cell lines of various tissues possess unique characteristics to maintain their normal functions for several months, these cell lines are extremely useful for not only toxicity testing but also pharmacological screening in new drug development. Professor Funatsu have studied the formation of spherical multicelluar aggregates of adult rat hepatocytes(spheroid) having tissue like structure. The sphcroid shown thre is a prototype module of an artificial liver support system. Thus, the urea synthesis activity of the artificial liver was maintained at least to days in 100％ rat blood plasma. Dr. Takezawa and his coworkers have developed a novel culture system of multicellular spheroids considered 〃organoids〃 by utilizing a thermo-responsive polymer as a substratum of anchorage dependent cells. His final goal is to reconstitute the organoids of various normal organs, e.g., liver, skin etc. and also abnormal deseased organs such as tumor.

• Journal of Life Science
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• v.22 no.9
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• pp.1145-1151
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• 2012

Aspirin and its deacetylated form, sodium salicylate (NaSal), have been shown to exert chemopreventive activities against many human cancers including those of the colon, lung, and breast. Previously, we showed that combined treatment of NaSal and genistein synergistically induced apoptosis in A549 lung cancer cells, indicating that these two natural chemicals could be used in combination for cancer therapy. In this study, we examined effects of NaSal/genistein combined treatment on other cancer cells and in three-dimensional multicellular tumor spheroid (MTS) and in an in vitro solid tumor model. We found that the combined treatment induces apoptosis in the HCT116 cells and the A549 cells, but not in the MCF-7 cells. Interestingly, the MCF-7 cells responded to the NaSal/genistein combined treatment by undergoing cell death when they were cultivated as MTS. The combined treatment induced apoptosis at an earlier stage in the MCF-7 MTS culture. However, when the MCF-7 MTS was cultivated for a longer period, it induced necrosis rather than apoptosis. We further found that the apoptotic pattern observed in MCF-7 MTS was incomplete: the chromatins were condensed and fragmented, but the nuclear membrane was still intact. Taken together, these results demonstrate that the NaSal/genistein combined treatment induces incomplete apoptosis and necrosis in the MCF-7 MTS culture system.