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Xian-Ying Fang,
Wei Chen,
Jun-Ting Fan, Ran Song,
Lu Wang,
Yan-Hong Gu,
Guang-Zhi Zeng,
Yan Shen,
Xue-Feng Wu,
Ning-Hua Tan,
Qiang Xu,
Yang Sun
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ABSTRACT: In the present paper, we examined the effects of a natural cyclopeptide RA-V on human breast cancer cells and the underlying mechanisms. RA-V significantly inhibited the growth of human breast cancer MCF-7, MDA-MB-231 cells and murine breast cancer 4T1 cells. In addition, RA-V triggered mitochondrial apoptotic pathway which was indicated by the loss of mitochondrial membrane potential, the release of cytochrome c, and the activation of caspase cascade. Further study showed that RA-V dramatically inhibited phosphorylation of AKT and 3-phosphoinositide dependent protein kinase 1 (PDK1) in MCF-7 cells. Moreover, RA-V disrupted the interaction between PDK1 and AKT in MCF-7 cells. Furthermore, RA-V-induced apoptosis could be enhanced by phosphatidylinositol 3-kinase inhibitor or attenuated by over-expression of AKT in all the three kinds of breast cancer cells. Taken together, this study shows that RA-V, which can induce mitochondria-mediated apoptosis, exerts strong anti-tumor activity against human breast cancer. The underlying anti-cancer mechanism of RA-V is related to the blockage of the interaction between PDK1 and AKT.
Toxicology and Applied Pharmacology 12/2012; · 4.45 Impact Factor
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ABSTRACT: In the present study, we demonstrate that SBF-1, a synthetic steroidal glycoside, has a strong antitumor activity against melanoma cells in vitro and in vivo. SBF-1 induced cell cycle arrest with a reduced expression of various cell cycle related proteins in B16BL6 melanoma cells without causing apoptosis. SBF-1 dramatically inhibited kinase activity of 3-phosphoinositide dependent protein kinase 1 (PDK1) and thus down-regulated phosphorylation of protein kinase B (AKT). Among three known isoforms of AKT, PDK1 only interacted with AKT3 in B16BL6 melanoma cells, and SBF-1 almost completely blocked this interaction. In addition, adhesion to fibronectin and expression of integrin α4 were significantly reduced in a concentration-dependent manner. Knockdown of AKT3 resulted in the decrease in integrin α4 expression and cell adhesion. Moreover, SBF-1 inhibited the growth of melanoma xenografts and down-regulated the phosphorylation of AKT in vivo. In a mouse model of spontaneous metastasis, SBF-1 at very low doses of 1 and 3 μg/kg enormously inhibited melanoma metastasis into draining popliteal lymph nodes. Taken together, this study shows a small molecular compound SBF-1 with a very strong anti-melanoma activity both in vitro and in vivo. Its mechanism underlying such antitumor effect is related to the blockage of the interaction between PDK1 and AKT3.
Biochemical pharmacology 04/2012; 84(2):172-81. · 4.25 Impact Factor
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ABSTRACT: A series of deoxybenzoin oximes were recently reported as potent immunosuppressive agents by our group. In order to continue the original research for potential immunosuppressive agents with high efficacy and low toxicity, we synthesized a series of new chalcone oximes and evaluated them for their cytotoxicities and immunosuppressive activities. Among the synthesized compounds, chalcone oximes 25 and 27 exhibited lower cytotoxicities and higher inhibitory activities on anti-CD3/anti-CD28 co-stimulated lymph node cells than other compounds. Specially, compound 27 displayed 200-fold lower cytotoxicity (CC(50)=2174.39 μM) than cyclosporin A (CC(50)=10.10 μM) and showed SI value (SI=176.69) close to cyclosporin A (SI=154.13). Besides, the preliminary mechanism of inhibition effect of compounds 25 and 27 was also detected by flow cytometry, and the compounds exerted immunosuppressive activities via inducing the apoptosis of activated lymph node cells in a dose dependent manner. Also, the deep mechanism of apoptosis was detected by Western blot analysis.
Bioorganic & medicinal chemistry letters 03/2012; 22(9):3039-43. · 2.65 Impact Factor
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ABSTRACT: Human liposarcoma is the most common soft tissue sarcoma. There is no effective therapy so far except for surgery. In this study, we report for the first time that curcumin induces endoplasmic reticulum (ER) stress in human liposarcoma cells via interacting with sarcoplasmic/endoplasmic reticulum Ca(2+)-ATPase 2 (SERCA2). Curcumin dose-dependently inhibited the cell survival of human liposarcoma cell line SW872 cells, but did not affect that of human normal adipose-derived cells. Curcumin-mediated ER stress via inhibiting the activity of SERCA2 caused increasing expressions of CHOP and its transcription target death receptor 5 (TRAIL-R2), leading to a caspase-3 and caspase-8 cascade-dependent apoptosis in SW872 cells in vitro and in vivo. Moreover, 70% of human liposarcoma tissues showed an elevated SERCA2 expression compared with normal adipose tissues. Curcumin dose-dependently inhibited the activity of SERCA2, and the interaction of molecular docking and colocalization in ER of curcumin with SERCA2 were further observed. These findings suggest that curcumin may serve as a potent agent for curing human liposarcoma via targeting SERCA2.
Molecular Cancer Therapeutics 01/2011; 10(3):461-71. · 5.23 Impact Factor
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ABSTRACT: In the search for potential immunosuppressive agents with high efficacy and low toxicity, a series of new deoxybenzoins were synthesized and evaluated for their cytotoxicity and immunosuppressive activity. Among the synthesized compounds, four deoxybenzoin oximes (compounds 31, 32, 37, and 38) exhibited lower cytotoxicity and higher inhibitory activity toward anti-CD3/anti-CD28 co-stimulated T-cell proliferation than other compounds. More significantly, compound 31 is >100-fold less cytotoxic than cyclosporine A (CsA) and is also more potent (31: SI>684.64, CsA: SI=235.44). The preliminary inhibition mechanism of compound 31 was also identified by flow cytometry, and this compound exerts immunosuppressive activity by inducing apoptosis in activated lymph node cells in a dose-dependent manner. In addition, the mechanism of apoptosis was detected by western blot analysis.
ChemMedChem 05/2010; 5(7):1117-22. · 3.15 Impact Factor
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ABSTRACT: Phosphatase of regenerating liver-3 (PRL-3) has been suggested as a potential target for anticancer drugs based on its involvement in tumor metastasis. However, little is known about a small-molecule inhibitor against PRL-3. In this study, we report that curcumin, the component of the spice turmeric, shows its antitumor effect by selectively down-regulating the expression of PRL-3 but not its family members PRL-1 and -2 in a p53-independent way. Curcumin inhibited the phosphorylation of Src and stat3 partly through PRL-3 down-regulation. Cells with PRL-3 stably knocked down show less sensitivity to curcumin treatment, which reveals that PRL-3 is the much further upstream target of curcumin. Curcumin treatment also remarkably prevented B16BL6 from invading the draining lymph nodes in the spontaneous metastatic tumor model, which is probably of relevance to PRL-3 down-regulation. Our results reveal a novel capacity of curcumin to down-regulate oncogene PRL-3, raising its possibility in therapeutic regimen against malignant tumor.
Molecular pharmacology 09/2009; 76(6):1238-45. · 4.53 Impact Factor
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ABSTRACT: Phosphatase of regenerating liver-3 (PRL-3) is a member of the novel phosphatases of regenerating liver family, characterized by one protein tyrosine phosphatase active domain and a C-terminal prenylation (CCVM) motif. Though widely proposed to facilitate metastasis in many cancer types, PRL-3's cellular localization and the function of its CCVM motif in metastatic process remain unknown.
In the present study, a series of Myc tagged PRL-3 wild type or mutant plasmids were expressed in B16F1 melanoma cells to investigate the relationship between PRL-3's cellular localization and metastasis. With immuno-fluorescence microcopy and cell adhesion/migration assay in vitro, and an experimental passive metastasis model in vivo, we found that CCVM motif is critical for the localization of PRL-3 on cell plasma membrane and the lung metastasis of melanoma. In particular, Cystine170 is the key site for prenylation in this process.
These results suggest that cellular localization of PRL-3 is highly correlated with its function in tumor metastasis, and inhibition of PRL-3 prenylation might be a new approach to cancer therapy.
PLoS ONE 02/2009; 4(2):e4450. · 4.09 Impact Factor
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ABSTRACT: Phosphatase of regenerating liver-3 (PRL-3) has been proposed to promote the invasion of tumor cells to metastasis sites. However, the effect of PRL-3 on spontaneous metastasis has not been clearly demonstrated, and whether PRL-3 could become a new therapeutic target in malignant tumor is still unknown. In this study, we used PRL-3 siRNA as a molecular medicine to specifically reduce the expression of PRL-3 in B16-BL6 cells, a highly metastatic melanoma cell line. In vitro, PRL-3 siRNA significantly inhibited cell adhesion and migration, but had no effect on cell proliferation. In the spontaneous metastatic tumor model in vivo, PRL-3 siRNA treatment remarkably inhibited the proliferation of primary tumor, prevented tumor cells from invading the draining lymph nodes, and prolonged the life span of mice. Therefore, our results indicate that PRL-3 plays a critical role in promoting the whole process of spontaneous metastasis and tumor growth initiation, and that inhibiting PRL-3 will improve malignant tumor therapy.
Molecular Medicine 13(3-4):151-9. · 3.76 Impact Factor
