Hae-Young Yong

The p38 MAPK inhibitors for the treatment of inflammatory diseases and cancer.

Background: The p38 mitogen-activated protein kinase (MAPK) is activated by various pro-inflammatory and stressful stimuli. Mounting evidence suggests that the p38 MAPK signaling cascade is involved in various biological responses other than inflammation such as cell proliferation, differentiation, apoptosis and invasion, suggesting that the p38 MAPK can serve as a potential therapeutic target for the treatment of not only inflammatory diseases but also cancer. Methods: The unique characteristics of p38 MAPK are summarized with regard to activation and function of p38 MAPK signaling cascades. We then discuss the involvement of p38 MAPK in diseases and the implications of the possible therapeutic use of p38 MAPK inhibitors. The p38 MAPK inhibitors that have been used in the in vitro/in vivo systems as well as in the clinical trials are summarized. Results/conclusion: The p38 MAPK plays an important role in key cellular processes related to inflammation and cancer. Understanding the signal transduction mechanisms and gene regulation by p38 MAPK provides useful information in the development of p38 MAPK inhibitors with therapeutic benefits with reduced side effects. In this review, we summarize and present the list of p38 MAPK inhibitors in in vitro/in vivo studies as well as in clinical trials.

Roles of calcium-binding proteins, S100A8 and S100A9, in invasive phenotype of human gastric cancer cells.

Gastric cancer is one of the most common malignancies and is a frequent cause of cancer-related death in Korea. Cure rate of gastric cancer is quite low because of local invasion and metastasis. S100 proteins are calcium-binding proteins which exert various calcium-mediated cellular functions including cell growth, differentiation, migration and signal transduction. S100A8 and S100A9 are overexpressed in many human tumors and have been shown to be implicated in tumor development or progression. In the present study, we investigated the role of S100A8 and S100A9 in invasive phenotype of a human gastric cancer cell line, SNU484. Expression of S100A8 and S100A9 were detected in SNU484 cells. When the expression of these proteins was suppressed by small-interfering RNA (siRNA) targeting S100A8 or S100A9, the invasive and migratory phenotypes of SNU484 cells were significantly inhibited. The siRNAs for S100A8 and S100A9 inhibited matrix metalloproteinase (MMP)-2 expression in SNU484 cells as evidenced by gelatin zymogram assay, immunoblot analysis and reverse transcription (RT)-PCR. These results demonstrate that S100A8 and S100A9 are required for transcriptional activation of MMP-2 gene in SNU484 cells. Taken together, this study revealed a functional contribution of S100A8 and S100A9 proteins to processes required for malignant progression including invasion, migration and proteinase expression in SNU484 human gastric cancer cells.

Denbinobin, a phenanthrene from dendrobium nobile, inhibits invasion and induces apoptosis in SNU-484 human gastric cancer cells

Dendrobium nobile is widely used as an analgesic, an antipyretic, and a tonic to nourish the stomach in traditional medicine. Mounting evidence suggests an antitumor activity of denbinobin, a major phenanthrene isolated from stems of Dendrobium nobile. The present study aimed to investigate the inhibitory effect of denbinobin on the invasive ability of human cancer cells. The cytotoxicity of denbonobin was examined in several human cancer cell lines including SK-Hep-1 hepato-carcinoma cells, SNU-484 gastric cancer cells, and HeLa cervix cancer cells. Because SNU-484 cells showed the lowest IC50 value, we examined the effect of denbinobin on the invasive ability of SNU-484 cells. The present study revealed, for the first time, that denbinobin inhibits the invasive phenotype of SNU-484 human gastric cancer cells in a dose-dependent manner. Expressions of matrix metalloproteinase (MMP)-2 and MMP-9 were significantly decreased by denbinobin, suggesting that MMP-2/-9 may be responsible for the anti-invasive activity of denbinobin. We also provide evidence that denbinobin induces apoptosis through down-regulation of Bcl-2 and an up-regulation of Bax. Taken together, this study demonstrates that denbinobin inhibits invasion and induces apoptosis in highly invasive SNU-484 human gastric cancer cells. Given that gastric cancer has been estimated to be one of the most common causes of cancer-related death among Asians and the major cause of death from gastric cancer is the metastatic spread of the disease, our findings may provide useful information regarding the application of denbinobin as a chemopreventive agent that could prevent or alleviate metastatic gastric cancer.

Abstract 5263: Identification of a lipid raft protein that is required for H-Ras activation and breast cancer aggressiveness

Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA In an attempt to identify biomarkers and/or therapeutic targets for malignant breast cancer, the present study showed a comparative proteome profiling of invasive MCF10A human breast epithelial cells engineered to express active H-Ras and non-invasive cells expressing active N-Ras. Here, we identified a lipid raft protein DS-20, a crucial regulator of H-Ras activation, as a potential marker for invasive breast cancer. DS-20 (amino acid residues 1-38) interacted with H-Ras (residues 166-189) in lipid rafts and their interaction was important for H-Ras activation. DS-20 knockdown inhibited H-Ras activation and invasion in Hs578T triple-negative breast cancer cells (TNBC) and T24 bladder carcinoma cells in which H-Ras is endogenously activated, suggesting a crucial role of DS-20 in the invasive program which relies on the activation of H-Ras. We further showed that DS-20 was required for epidermal growth factor-induced H-Ras activation, but not that of N-Ras, in MDA-MB-231 TNBC cells. Intravasation of MDA-MB-231 cells treated with shRNA DS-20 in the chick chorioallantoic membrane model was markedly reduced, indicating that DS-20 is required for an invasive capacity in vivo. In a xenograft mice tumor model, DS-20 was essential for in vivo tumor aggressiveness of Hs578T cells, suggesting DS-20 as a potential target for the treatment of breast cancer. Using human breast cancer samples, we provide clinical evidence for the tumorigenic potential of DS-20 and its association with H-Ras. Taken together, our findings provide a new insight into the molecular basis of Ras isoform-specific interplay with plasma membrane leading to cell invasion. Citation Format: Hae-Young Yong, Eun-Sook Kim, Minsoo Koh, Hwajin Son, You Rim Jeon, Jin-Sun Hwang, Myeong-Ok Kim, Yujin Cha, Wahn Soo Choi, Dong-Young Noh, Kyung-Min Lee, Ki-Bum Kim, Jae-Seon Lee, Hyung Joon Kim, Hong-Hee Kim, Eun Joo Kim, So Yeon Park, Hyeong-Reh Choi Kim, Aree Moon. Identification of a lipid raft protein that is required for H-Ras activation and breast cancer aggressiveness. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5263. doi:10.1158/1538-7445.AM2014-5263

Abstract 4165: Identification of flotillin-1 as a regulator of H-Ras activation in lipid raft

Proceedings: AACR 103rd Annual Meeting 2012‐‐ Mar 31‐Apr 4, 2012; Chicago, IL Metastatic spread is the major cause of death from breast cancer. We previously showed that H-Ras, but not N-Ras, induces invasive/migratory phenotypes of MCF10A human breast epithelial cells, while both H-Ras and N-Ras induce proliferation/transformation. Here, we identified flotillin-1 as an H-Ras-induced lipid raft protein through comparative proteome profiling of lipid raft proteins. Flotillin-1 interacts with H-Ras in lipid raft at a higher affinity than with N-Ras. Small interfering RNA(siRNA)-mediated flotillin-1 knockdown significantly reduced H-Ras activation and H-Ras-mediated motility/invasion in MCF10A cells engineered to express active H-Ras as well as in Hs578T breast carcinoma and T24 bladder carcinoma cells that express endogenous active mutant of H-Ras. These results suggest a positive signal amplification loop between flotillin-1 and H-Ras for the invasive signaling program. Flotillin-1 was crucial for the activation of the Ras-GRF1 exchange factor and its interaction with H-Ras in lipid rafts. Using a xenograft tumor model, we show that knockdown of flotillin-1 reduces the tumor growth in vivo. Importantly, tissue microarrays of 289 breast cancer patients revealed that flotillin-1 expression in the plasma membrane positively correlates with HER2/neu expression(p<0.001) and high histologic grade(p=0.014). Although infrequent, the membranous flotillin-1 expression is significantly associated with poor disease-free survival of patients(p=0.005), suggesting the clinical importance of predicting the characteristics of a small subpopulation of malignant breast cancer. Taken together, our findings provide new insight into the molecular basis of the Ras isoform-specific signaling mechanism leading to cell invasion that depends on the lipid-based sorting platforms. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4165. doi:1538-7445.AM2012-4165

Abstract 1062: Identification of flotilin-1 as an H-Ras-interacting lipid raft protein: Its implications in breast epithelial cell invasion

Proceedings: AACR 102nd Annual Meeting 2011‐‐ Apr 2‐6, 2011; Orlando, FL Metastatic spread is the major cause of death from breast cancer. We previously showed that H-Ras, but not N-Ras, induces invasive/migratory phenotypes of MCF10A human breast epithelial cells, while both H-Ras and N-Ras induce proliferation/transformation. Here, we identified flotillin-1 as an H-Ras-induced lipid raft protein through comparative proteome profiling of lipid raft proteins. Flotillin-1 interacts with H-Ras in lipid raft at a higher affinity than with N-Ras, elucidating a molecular nature of the crucial link between lipid rafts and the function of H-Ras. Small interfering RNA (siRNA)-mediated flotillin-1 knockdown significantly reduced H-Ras activation and H-Ras-mediated motility/invasion in MCF10A cells engineered to express H-Ras and in highly invasive human breast carcinoma Hs578T cells that express endogenous H-Ras. These results suggest a positive signal amplification loop between flotillin-1 and H-Ras for the invasive signaling program in breast epithelial cells. Importantly, tissue microarrays of 289 patients with invasive breast cancer revealed that flotillin-1 expression positively correlates with lymph node metastases (p=0.027), HER2/neu oncogene expression (p<0.001), and high histologic grade (p=0.014). Although infrequent, the membranous flotillin-1 expression is significantly associated with poor disease-free survival of patients (p=0.005), suggesting the clinical importance of predicting the characteristics of a small subpopulation of malignant breast cancer. Taken together, our findings provide new insight into the molecular basis of the Ras isoform-specific signaling mechanism that depends on the lipid-based sorting platforms. [This work was supported by the Korea government (Nos.ROA-2008-000-20070-0)] Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1062. doi:10.1158/1538-7445.AM2011-1062

Abstract 5197: Comparative proteome analysis reveals flotillin-1 as an H-Ras-interacting lipid raft protein critical for breast epithelial cell invasion

Metastatic spread is the major cause of death from breast cancer. The objective of our study is to unveil signal transduction pathways specific to breast epithelial cell invasion and migration apart from cell proliferation/transformation. We previously showed that the active H-Ras, but not N-Ras, induces invasive/migratory phenotypes of MCF10A human breast epithelial cells via activation of Rac1/p38 signaling leading to MMP-2 up-regulation, while both H-Ras and N-Ras induce cell proliferation and transformation. In the present study, we hypothesized that the Ras isoform-specific signaling pathway is initiated by differential involvement of lipid raft proteins. To address this, we characterized proteome profiles of lipid raft proteins from three cell lines: normal MCF10A; N-Ras-transformed, non-invasive MCF10A; and H-Ras-transformed, invasive MCF10A cells. Among twenty-four lipid raft proteins that were up-regulated in an H-Ras-specific manner, we tested whether flotillin-1 plays a causative role for H-Ras-mediated MCF10A cell invasion/migration. Here, we show that flotillin-1 interacts with H-Ras and H-Ras signaling increases flotillin-1 expression, suggesting a signaling amplification loop between flotillin-1 and H-Ras. Importantly, siRNA-mediated flotillin-1 knockdown significantly reduced H-Ras-mediated motility/invasion accompanied with down-regulation of Rac1/p38 and MMP-2. We also show that flotillin-1 co-localizes with H-Ras in the plasma membrane, while the interaction between flotillin-1 and N-Ras was negligible. Taken together, this study identified flotillin-1 as an H-Ras-interacting lipid raft protein critical for activation of H-Ras-specific signaling resulting invasive phenotype in breast epithelial cells. Consistently, flotillin-1 mRNA was significantly higher in malignant breast cancer tissues, supporting our hypothesis that flotillin-1 may contribute to breast carcinoma invasion. Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5197.