Epithelial-to-mesenchymal transition (EMT) is a critical cellular phenomenon regulating tumor metastases. In the present study, we investigated whether ginkgolic acid can affect EMT in lung cancer cells and the related underlying mechanism(s) of its actions. We found that ginkgolic acid C15:1 (GA C15:1) inhibited cell proliferation, invasion, and migration in both A549 and H1299 lung cancer cells. GA C15:1 also suppressed the expression of EMT related genes (Fibronectin, Vimentin, N-cadherin, MMP-9, MMP-2, Twist and Snail) and suppressed TGF-β-induced EMT as assessed by reduced expression of mesenchymal markers (Fibronectin, Vimentin, N-cadherin), MMP-9, MMP-2, Twist and Snail. However, GA C15:1 did not affect the expression of various epithelial marker proteins (Occludin and E-cadherin) in both A549 and H1299 cells. TGF-β-induced morphologic changes from epithelial to mesenchymal cells and induction of invasion and migration were reversed by GA C15:1. Finally, GA C15:1 not only abrogated basal PI3K/Akt/mTOR signaling cascade, but also reduced TGF-β-induced phosphorylation of PI3K/Akt/mTOR pathway in lung cancer cells. Overall, these findings suggest that GA C15:1 suppresses lung cancer invasion and migration through the inhibition of PI3K/Akt/mTOR signaling pathway and provide a source of potential therapeutic compounds to control the metastatic dissemination of tumor cells. J. Cell. Physiol. 232: 346-354, 2017. © 2016 Wiley Periodicals, Inc.

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Persistent STAT3 activation is seen in many tumor cells and promotes malignant transformation. Here, we investigated whether capsazepine (Capz), a synthetic analogue of capsaicin, exerts anticancer effects by inhibiting STAT3 activation in prostate cancer cells. Capz inhibited both constitutive and induced STAT3 activation in human prostate carcinoma cells. Capz also inhibited activation of the upstream kinases JAK1/2 and c-Src. The phosphatase inhibitor pervanadate reversed Capz-induced STAT3 inhibition, indicating that the effect of Capz depends on a protein tyrosine phosphatase. Capz treatment increased PTPε protein and mRNA levels. Moreover, siRNA-mediated knockdown of PTPε reversed the Capz-induced induction of PTPε and inhibition of STAT3 activation, indicating that PTPε is crucial for Capz-dependent STAT3 dephosphorylation. Capz also decreased levels of the protein products of various oncogenes, which in turn inhibited proliferation and invasion and induced apoptosis. Finally, intraperitoneal Capz administration decreased tumor growth in a xenograft mouse prostate cancer model and reduced p-STAT3 and Ki-67 expression. These data suggest that Capz is a novel pharmacological inhibitor of STAT3 activation with several anticancer effects in prostate cancer cells.

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Energy expenditure is a target gaining recent interest for obesity treatment. The antiobesity effect of vanillic acid (VA), a well-known flavoring agent, was investigated in vivo and in vitro. High-fat diet (HFD)-induced obese mice and genetically obese db/db mice showed significantly decreased body weights after VA administration. Two major adipogenic markers, peroxisome proliferator activated receptor γ (PPARγ) and CCAAT/enhancer-binding protein α (C/EBPα), were reduced while the key factor of energy metabolism, AMPKα, was increased in the white adipose tissue and liver tissue of VA-treated mice. Furthermore, VA inhibited lipid accumulation and reduced hepatotoxic/inflammatory markers in liver tissues of mice and HepG2 hepatocytes. VA treatment also decreased differentiation of 3T3-L1 adipocytes by regulating adipogenic factors including PPARγ and C/EBPα. AMPKα small interfering RNA was used to examine whether AMPK was associated with the actions of VA. In AMPKα-nulled 3T3-L1 cells, the inhibitory action of VA on PPARγ and C/EBPα was attenuated. Furthermore, in brown adipose tissues of mice and primary cultured brown adipocytes, VA increased mitochondria- and thermogenesis-related factors such as uncoupling protein 1 and PPARγ-coactivator 1-α. Taken together, our results suggest that VA has potential as an AMPKα- and thermogenesis-activating antiobesity agent.-Jung, Y., Park, J., Kim, H.-L., Sim, J.-E., Youn, D.-H., Kang, J., Lim, S., Jeong, M.-Y., Yang, W. M., Lee, S.-G., Ahn, K. S., Um, J.-Y. Vanillic acid attenuates obesity via activation of the AMPK pathway and thermogenic factors in vivo and in vitro.

Ginkgolic acid C 17:1 (GAC 17:1) extracted from Ginkgo biloba leaves, has been previously reported to exhibit diverse antitumor effect(s) through modulation of several molecular targets in tumor cells, however the detailed mechanism(s) of its actions still remains to be elucidated. Signal transducer and activator of transcription 3 (STAT3) is an oncogenic transcription factor that regulates various critical functions involved in progression of diverse hematological malignancies, including multiple myeloma, therefore attenuating STAT3 activation may have a potential in cancer therapy. We determined the anti-tumor mechanism of GAC 17:1 with respect to its effect on STAT3 signaling pathway in multiple myeloma cell lines. We found that GAC 17:1 can inhibit constitutive activation of STAT3 through the abrogation of upstream JAK2, Src but not of JAK1 kinases in U266 cells and also found that GAC can suppress IL-6-induced STAT3 phosphorylation in MM.1S cells. Treatment of protein tyrosine phosphatase (PTP) inhibitor blocked suppression of STAT3 phosphorylation by GAC 17:1, thereby indicating a critical role for a PTP. We also demonstrate that GAC 17:1 can induce the substantial expression of PTEN and SHP-1 at both protein and mRNA level. Further, deletion of PTEN and SHP-1 genes by siRNA can repress the induction of PTEN and SHP-1, as well as abolished the inhibitory effect of drug on STAT3 phosphorylation. GAC 17:1 down-regulated the expression of STAT3 regulated gene products and induced apoptosis of tumor cells. Overall, GAC 17:1 was found to abrogate STAT3 signaling pathway and thus exert its anticancer effects against multiple myeloma cells.

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