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121 AMPK-p63 signaling in lovastatin-induced Fadu hypopharyngeal carcinoma cell death
Abstracts 121 POSTER AMPK-p63 signaling in lovastatin-induced Fadu hypopharyngeal carcinoma cell death Y.F. Chuang1 . 1 Taipei Medical University, Graduate Institute of Medical Sciences, Taipei, Taiwan
S7 123 POSTER Src-FAK-STAT3 signaling in Interleukin-6-induced lymphatic endothelial cell vascular endothelial growth factor-C expression and lymphangiogenesis Y.H. Huang1 . 1 Taipei Medical University, Graduate Institute of Medical Sciences, Taipei, Taiwan
Background: Histone deacetylase (HDAC) inhibitors have been shown to exhibit anti-tumor effects by inducing cell cycle arrest, cell apoptosis, and suppressing metastasis. Thus, HDAC inhibitors have emerged as a new class of anti-tumor agents. Statins, the 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, were recently demonstrated to inhibit HDACs and exhibit anti-tumor activities. However, the molecular mechanism underlying statin-induced cancer cell death remains to be fully defined. Elevated survivin level is found in various types of tumors. It has also been implicated in the progression of tumorigenesis. Survivin thus represents a potential molecular target in the treatment of cancer. Material and Methods: In this study, we explored the underlying mechanisms of lovastatin in inducing Fadu hypopharyngeal carcinoma cell death. Results: Lovastatin decreased cell viability and induced cell apoptosis in Fadu cells. These results are associated with the modulation of p21(cip/Waf1), cyclin D1 and survivin. Lovastatin caused an increase in p63 phosphorylation and acetylation. Lovastatin’s actions on p21cip/Waf, cyclin D1 and survivin were reduced in Fadu cells with p63 knockdown. In addition, lovastatin activated AMP-activated protein kinase (AMPK), whereas AMPK dominant negative mutant (AMPK-DN) abrogated lovastatin’s effects of increasing p63 phosphorylation. Lovastatin’s effects in modulating p21cip/Waf1, surviving and cyclin D1 levels were also reduced by AMPKDN. Over-expression of HDAC3 and HDAC4 abrogated lovastatin’s effects of increasing p63 acetylation. Moreover, Sp1 binding to the survivin promoter region decreased while p63 binding to the promoter region increased after lovastatin exposure. Furthermore, lovastatin suppressed tumor growth in in vivo xenograft animal model. Conclusions: Lovastatin activates the AMPK-p63-survivin cascade to cause Fadu hypopharyngeal carcinoma cell death. No conflict of interest.
Background: The difficulties in cancer treatment are attributed to the metastatic ability of cancer cells. Interleukin-6 (IL-6), a potent proinflammatory cytokine, is highly up-regulated in various cancers. It has been shown to increase pro-lymphangiogenic factor vascular endothelial growth factor-C (VEGF-C) in tumor cells as well as lymphatic endothelial cells (LECs). Although lymphangiogenesis is associated with lymph node metastasis and also resistance to conventional therapy in various cancers, the precise mechanisms of lymphangiogenesis in LECs remain to be fully defined. Material and Methods: In this study, we explored the underlying mechanisms of IL-6 in inducing VEGF-C expression in murine LECs (SVLECs). Results: IL-6/sIL-6R-stimulated migration and tubular formation of SVLECs were suppressed in the presence of focal adhesion kinase (FAK) inhibitor. In addition to FAK, Src, which is the upstream regulator of FAK, also contributes to IL-6/sIL-6R-induced migration and tubular formation. FAK inhibitor abrogated the IL-6/sIL-6R’s effects of increasing VEGF-C level as well as promoter-luciferase activities. Moreover, IL-6/sIL-6R-increased phosphorylation of ERK1/2, p38MAPK, C/EBP and STAT3 were all reduced by FAK inhibitor. C/EBPb-, úB- and STAT3-luciferase activities were also reduced by FAK inhibitor despite the presence of IL-6/sIL-6R. In addition, Src-FAK signaling blockade attenuated IL-6/sIL-6R’s effects on STAT3 binding to the VEGF-C promoter region. Furthermore, transfection of cells with STAT3 siRNA attenuated IL-6/sIL-6R − increased VEGF-C mRNA and protein levels in SV-LECs. Conclusions: We report a Src-mediated FAK activation resulting in STAT3 binding to the promoter region of VEGF-C, leading to VEGF-C expression in IL-6-exposed SV-LECs. No conflict of interest.
122 POSTER Src signaling in Interleukin-6-induced epithelial-mesenchymal transition in HCT116 colorectal cancer cells
124 POSTER A novel angiogenesis inhibitor, DDA, inhibits tumor growth and angiogenesis
M.J. Hsu1 . 1 Taipei Medical University, Department of Pharmacology, Taipei, Taiwan
S.W. Huang1 . 1 National Taiwan University, Graduate Institute of Pharmacology, Taipei, Taiwan
Background: Cancer is an increasingly prevalent health problem around the world. The difficulties in cancer treatment are attributed to the metastatic spread of tumor cells, which is the leading cause of cancer related deaths. The aberrant activation of epithelial-to-mesenchymal transition (EMT) has been implicated in the enhanced metastasis. Growing evidence suggest that inflammation promotes epithelial-to-mesenchymal transition (EMT). A crucial mediator of the tumor-promoting effects of inflammation is interleukin-6 (IL-6). Elevated serum IL-6 has been associated with advanced stages, metastasis and decreased survival of colorectal cancer patients. However, the molecular mechanisms underlying these associations remain to be fully defined. Material and Methods: In this study, we explored the underlying mechanisms of IL-6 in inducing EMT in HCT116 colorectal cancer cells. Results: Treatment of HCT116 colorectal cancer cells with IL-6 results in EMT, as evidenced by induction of the mesenchymal markers snail, slug and twist, repression of the epithelial marker E-cadherin and increased cell motility. IL-6 caused increases in phosphorylation of Src, FAK, ERK1/2, p38MAPK, STAT3 and C/EBP. In contrast, PP2, an inhibitor of Src signaling, abrogated IL-6’s effects on FAK, ERK1/2 and p38MAPK phosphorylation as well as STAT3 and C/EBP phosphorylation. Moreover, PP2 and STAT3 siRNA suppressed IL-6-induced EMT. Results from chromatin immunoprecipitation (ChIP) analysis further showed that STAT3 and C/EBP binding to the twist promoter region were increased after IL-6 exposure in HCT116 cells. Conclusions: These results suggest that IL-6 may induce EMT in HCT116 colorectal cancer cells via Src signaling. Activation of STAT3 and C/EBP resulting in twist elevation may also contribute to IL-6 actions. No conflict of interest.
Background: Angiogenesis plays a role in the pathogenesis of ischemic, inflammatory, immune disorders and numerous malignancies. It is a balanced process that involves proliferation, migration, differentiation and tube formation of endothelial cells. As a critical factor in inducing angiogenesis, vascular endothelial growth factor (VEGF) has become an attractive target for anti-angiogenesis treatment. Material and Methods: In an effort to develop inhibitors to block VEGF signaling and angiogenesis, an anthraquinone derivative, DDA, was evaluated for its anti-angiogenesis activity using human umbilical endothelial cells (HUVECs). Results: DDA concentration-dependently inhibited VEGF-induced proliferation, migration and tube formation of HUVECs. DDA also suppressed VEGF-induced microvessel sprouting from aortic rings in an ex vivo model. Furthermore, DDA blocked angiogenesis in a matrigel plugs assay. In addition, DDA inhibited VEGF-induced VEGFR2 phosphorylation and suppressed the activity of VEGFR-2-mediated signaling cascades such as focal adhesion kinase (FAK), STAT3, Akt and ERK. Using an implanted matrigel plugs angiogenesis model, DDA attenuated MDAMB-231 breast cancer cells-induced angiogenesis. In addition, in a colorectal cancer xenografts model, systemic administration of DDA suppressed the tumor growth and tumor angiogenesis in vivo. Conclusions: Our findings reveal that DDA inhibits VEGF-induced angiogenesis via downregulation of VEGFR2-mediated signaling, suggesting that DDA is a potential drug candidate in anti-cancer therapy through suppressing tumor-induced angiogenesis. No conflict of interest.
S7 123 POSTER Src-FAK-STAT3 signaling in Interleukin-6-induced lymphatic endothelial cell vascular endothelial growth factor-C expression and lymphangiogenesis Y.H. Huang1 . 1 Taipei Medical University, Graduate Institute of Medical Sciences, Taipei, Taiwan
Background: Histone deacetylase (HDAC) inhibitors have been shown to exhibit anti-tumor effects by inducing cell cycle arrest, cell apoptosis, and suppressing metastasis. Thus, HDAC inhibitors have emerged as a new class of anti-tumor agents. Statins, the 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, were recently demonstrated to inhibit HDACs and exhibit anti-tumor activities. However, the molecular mechanism underlying statin-induced cancer cell death remains to be fully defined. Elevated survivin level is found in various types of tumors. It has also been implicated in the progression of tumorigenesis. Survivin thus represents a potential molecular target in the treatment of cancer. Material and Methods: In this study, we explored the underlying mechanisms of lovastatin in inducing Fadu hypopharyngeal carcinoma cell death. Results: Lovastatin decreased cell viability and induced cell apoptosis in Fadu cells. These results are associated with the modulation of p21(cip/Waf1), cyclin D1 and survivin. Lovastatin caused an increase in p63 phosphorylation and acetylation. Lovastatin’s actions on p21cip/Waf, cyclin D1 and survivin were reduced in Fadu cells with p63 knockdown. In addition, lovastatin activated AMP-activated protein kinase (AMPK), whereas AMPK dominant negative mutant (AMPK-DN) abrogated lovastatin’s effects of increasing p63 phosphorylation. Lovastatin’s effects in modulating p21cip/Waf1, surviving and cyclin D1 levels were also reduced by AMPKDN. Over-expression of HDAC3 and HDAC4 abrogated lovastatin’s effects of increasing p63 acetylation. Moreover, Sp1 binding to the survivin promoter region decreased while p63 binding to the promoter region increased after lovastatin exposure. Furthermore, lovastatin suppressed tumor growth in in vivo xenograft animal model. Conclusions: Lovastatin activates the AMPK-p63-survivin cascade to cause Fadu hypopharyngeal carcinoma cell death. No conflict of interest.
Background: The difficulties in cancer treatment are attributed to the metastatic ability of cancer cells. Interleukin-6 (IL-6), a potent proinflammatory cytokine, is highly up-regulated in various cancers. It has been shown to increase pro-lymphangiogenic factor vascular endothelial growth factor-C (VEGF-C) in tumor cells as well as lymphatic endothelial cells (LECs). Although lymphangiogenesis is associated with lymph node metastasis and also resistance to conventional therapy in various cancers, the precise mechanisms of lymphangiogenesis in LECs remain to be fully defined. Material and Methods: In this study, we explored the underlying mechanisms of IL-6 in inducing VEGF-C expression in murine LECs (SVLECs). Results: IL-6/sIL-6R-stimulated migration and tubular formation of SVLECs were suppressed in the presence of focal adhesion kinase (FAK) inhibitor. In addition to FAK, Src, which is the upstream regulator of FAK, also contributes to IL-6/sIL-6R-induced migration and tubular formation. FAK inhibitor abrogated the IL-6/sIL-6R’s effects of increasing VEGF-C level as well as promoter-luciferase activities. Moreover, IL-6/sIL-6R-increased phosphorylation of ERK1/2, p38MAPK, C/EBP and STAT3 were all reduced by FAK inhibitor. C/EBPb-, úB- and STAT3-luciferase activities were also reduced by FAK inhibitor despite the presence of IL-6/sIL-6R. In addition, Src-FAK signaling blockade attenuated IL-6/sIL-6R’s effects on STAT3 binding to the VEGF-C promoter region. Furthermore, transfection of cells with STAT3 siRNA attenuated IL-6/sIL-6R − increased VEGF-C mRNA and protein levels in SV-LECs. Conclusions: We report a Src-mediated FAK activation resulting in STAT3 binding to the promoter region of VEGF-C, leading to VEGF-C expression in IL-6-exposed SV-LECs. No conflict of interest.
122 POSTER Src signaling in Interleukin-6-induced epithelial-mesenchymal transition in HCT116 colorectal cancer cells
124 POSTER A novel angiogenesis inhibitor, DDA, inhibits tumor growth and angiogenesis
M.J. Hsu1 . 1 Taipei Medical University, Department of Pharmacology, Taipei, Taiwan
S.W. Huang1 . 1 National Taiwan University, Graduate Institute of Pharmacology, Taipei, Taiwan
Background: Cancer is an increasingly prevalent health problem around the world. The difficulties in cancer treatment are attributed to the metastatic spread of tumor cells, which is the leading cause of cancer related deaths. The aberrant activation of epithelial-to-mesenchymal transition (EMT) has been implicated in the enhanced metastasis. Growing evidence suggest that inflammation promotes epithelial-to-mesenchymal transition (EMT). A crucial mediator of the tumor-promoting effects of inflammation is interleukin-6 (IL-6). Elevated serum IL-6 has been associated with advanced stages, metastasis and decreased survival of colorectal cancer patients. However, the molecular mechanisms underlying these associations remain to be fully defined. Material and Methods: In this study, we explored the underlying mechanisms of IL-6 in inducing EMT in HCT116 colorectal cancer cells. Results: Treatment of HCT116 colorectal cancer cells with IL-6 results in EMT, as evidenced by induction of the mesenchymal markers snail, slug and twist, repression of the epithelial marker E-cadherin and increased cell motility. IL-6 caused increases in phosphorylation of Src, FAK, ERK1/2, p38MAPK, STAT3 and C/EBP. In contrast, PP2, an inhibitor of Src signaling, abrogated IL-6’s effects on FAK, ERK1/2 and p38MAPK phosphorylation as well as STAT3 and C/EBP phosphorylation. Moreover, PP2 and STAT3 siRNA suppressed IL-6-induced EMT. Results from chromatin immunoprecipitation (ChIP) analysis further showed that STAT3 and C/EBP binding to the twist promoter region were increased after IL-6 exposure in HCT116 cells. Conclusions: These results suggest that IL-6 may induce EMT in HCT116 colorectal cancer cells via Src signaling. Activation of STAT3 and C/EBP resulting in twist elevation may also contribute to IL-6 actions. No conflict of interest.
Background: Angiogenesis plays a role in the pathogenesis of ischemic, inflammatory, immune disorders and numerous malignancies. It is a balanced process that involves proliferation, migration, differentiation and tube formation of endothelial cells. As a critical factor in inducing angiogenesis, vascular endothelial growth factor (VEGF) has become an attractive target for anti-angiogenesis treatment. Material and Methods: In an effort to develop inhibitors to block VEGF signaling and angiogenesis, an anthraquinone derivative, DDA, was evaluated for its anti-angiogenesis activity using human umbilical endothelial cells (HUVECs). Results: DDA concentration-dependently inhibited VEGF-induced proliferation, migration and tube formation of HUVECs. DDA also suppressed VEGF-induced microvessel sprouting from aortic rings in an ex vivo model. Furthermore, DDA blocked angiogenesis in a matrigel plugs assay. In addition, DDA inhibited VEGF-induced VEGFR2 phosphorylation and suppressed the activity of VEGFR-2-mediated signaling cascades such as focal adhesion kinase (FAK), STAT3, Akt and ERK. Using an implanted matrigel plugs angiogenesis model, DDA attenuated MDAMB-231 breast cancer cells-induced angiogenesis. In addition, in a colorectal cancer xenografts model, systemic administration of DDA suppressed the tumor growth and tumor angiogenesis in vivo. Conclusions: Our findings reveal that DDA inhibits VEGF-induced angiogenesis via downregulation of VEGFR2-mediated signaling, suggesting that DDA is a potential drug candidate in anti-cancer therapy through suppressing tumor-induced angiogenesis. No conflict of interest.