Dihydromyricetin suppresses cell metastasis in human osteosarcoma through SP-1- and NF-κB-modulated urokinase plasminogen activator inhibition.

BACKGROUND: Metastasis caused a decline in the 5-years survival rate of osteosarcoma. Therefore, developing new targeted therapeutics for osteosarcoma treatment is imperative. Dihydromyricetin (DHM) has several physiological functions: it counteracts inflammation, oxidation, and antitumor properties. However, the effects of DHM on osteosarcoma and its underlying mechanisms are still not well understood. PURPOSE: In this study, we investigated the antimetastatic properties of DHM in human osteosarcoma U-2 OS and HOS cells. METHODS: The effects of DHM (0, 25, 50, 75, and 100 µM) on cell viability, migration, and invasion were examined. Western blotting, RT-PCR, and quantitative real-time PCR (QPCR) were determined urokinase plasminogen activator (uPA) expression. The expression of transcriptional factor SP-1 and NF-κB was determined by using immunofluorescence assay, chromatin immunoprecipitation assay, and site-directed mutagenesis luciferase reporter. RESULTS: We observed that DHM suppresses cell migration and invasion in osteosarcoma cell lines. In addition, DHM inhibits metastasis by downregulating urokinase plasminogen activator (uPA) expression. Moreover, real-time polymerase chain reaction and promoter activity assays revealed that DHM decreased uPA expression at transcription levels. Furthermore, the inhibition of uPA expression was associated with the suppression of SP-1 and NF-κB, which bind to the uPA promoter. Regardless of blocking or inducing the extracellular signal-regulated kinase (ERK) pathway, we verified that the DHM-related suppression of uPA and cell metastasis occurred through the p-ERK pathway. CONCLUSION: We are the first study to propose that DHM suppresses osteosarcoma metastasis through the ERK pathway and through the suppression of SP-1 and NF-κB to inhibit downstream uPA expression. DHM is a potential therapeutic agent for antimetastatic therapy against osteosarcoma.

Molecular and Cellular Mechanisms of Melatonin in Osteosarcoma.

Osteosarcoma, the most common primary bone malignancy, occurs most frequently in adolescents with a peak of incidence at 11-15 years. Melatonin, an indole amine hormone, shows a wide range of anticancer activities. The decrease in melatonin levels simultaneously concurs with the increase in bone growth and the peak age distribution of osteosarcoma during puberty, so melatonin has been utilized as an adjunct to chemotherapy to improve the quality of life and clinical outcomes. While a large amount of research has been conducted to understand the complex pleiotropic functions and the molecular and cellular actions elicited by melatonin in various types of cancers, a few review reports have focused on osteosarcoma. Herein, we summarized the anti-osteosarcoma effects of melatonin and its underlying molecular mechanisms to illustrate the known significance of melatonin in osteosarcoma and to address cellular signaling pathways of melatonin in vitro and in animal models. Even in the same kind of osteosarcoma, melatonin has been sparingly investigated to counteract tumor growth, apoptosis, and metastasis through different mechanisms, depending on different cell lines. We highlighted the underlying mechanism of anti-osteosarcoma properties evoked by melatonin, including antioxidant activity, anti-proliferation, induction of apoptosis, and the inhibition of invasion and metastasis. Moreover, we discussed the drug synergy effects of the role of melatonin involved and the method to fortify the anti-cancer effects on osteosarcoma. As a potential therapeutic agent, melatonin is safe for children and adolescents and is a promising candidate for an adjuvant by reinforcing the therapeutic effects and abolishing the unwanted consequences of chemotherapies.

Geraniin inhibits oral cancer cell migration by suppressing matrix metalloproteinase-2 activation through the FAK/Src and ERK pathways.

Geraniin has been reported to have numerous biological activities, including antiviral, antihypertensive, antihyperglycaemic, liver protective, antidiabetic, and apoptotic activities. However, the anti-migration effects of geraniin on oral cancer remain elusive. In this study, we revealed the potential antitumor mechanisms of geraniin through the inhibition of the migration and invasion of human oral cancer cell lines SCC-9 and SCC-14. The results of gelatin zymography and Western blot assays revealed that geraniin significantly reduced the activity and expression of matrix metalloproteinase-2 (MMP-2) of oral cancer cells in a concentration-dependent manner. Furthermore, geraniin potently suppressed the phosphorylation of focal adhesion kinase (FAK), Src, and extracellular signal-regulated kinase (ERK)1/2 but did not affect the phosphorylation of p38 mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase 1/2. Moreover, blocking the MAPK/ERK1/2 pathway significantly enhanced the anti-migration ability of geraniin in oral cancer cells. In conclusion, we demonstrated that geraniin inhibits the motility of SCC-9 and SCC-14 cells in vitro through a molecular mechanism that involves the attenuation of MMP-2 expression and activity mediated by decreased FAK/Src and ERK1/2 pathways.

Selaginella tamariscina (Beauv.) possesses antimetastatic effects on human osteosarcoma cells by decreasing MMP-2 and MMP-9 secretions via p38 and Akt signaling pathways.

Selaginella tamariscina is a traditional medicinal plant for treatment of some advanced cancers in the Orient. However, the effect of S. tamariscina on metastasis of osteosarcoma and the underlying mechanism remain unclear. We tested the hypothesis that S. tamariscina suppresses cellular motility, invasion and migration and also investigated its signaling pathways. This study demonstrates that S. tamariscina, at a range of concentrations (from 0 to 50 µg/mL), concentration-dependently inhibited the migration/invasion capacities of three osteosarcoma cell lines without cytotoxic effects. Zymographic and western blot analyses revealed that S. tamariscina inhibited the matrix metalloproteinase (MMP)-2 and MMP-9 enzyme activity, as well as protein expression. Western blot analysis also showed that S. tamariscina inhibits phosphorylation of p38 and Akt. Furthermore, SB203580 (p38 inhibitor) and LY294002 (PI3K inhibitor) showed the similar effects as S. tamariscina in U2OS cells. In conclusion, S. tamariscina possesses an antimetastatic activity in osteosarcoma cells by down-regulating MMP-2 and MMP-9 secretions and increasing TIMP-1 and TIMP-2 expressions through p38 and Akt-dependent pathways. S. tamariscina may be a powerful candidate to develop a preventive agent for osteosarcoma metastasis.

Selaginellatamariscina attenuates metastasis via Akt pathways in oral cancer cells.

BACKGROUND: Crude extracts of Selaginellatamariscina, an oriental medicinal herb, have been evidenced to treat several human diseases. This study investigated the mechanisms by which Selaginellatamariscina inhibits the invasiveness of human oral squamous-cell carcinoma (OSCC) HSC-3 cells. METHODOLOGY/PRINCIPAL FINDINGS: Herein, we demonstrate that Selaginellatamariscina attenuated HSC-3 cell migration and invasion in a dose-dependent manner. The anti-metastatic activities of Selaginellatamariscina occurred at least partially because of the down-regulation of matrix metalloproteinases (MMP)-2 and MMP-9 gelatinase activity and the down-regulation of protein expression. The expression and function of both MMP-2 and MMP-9 were regulated by Selaginellatamariscina at a transcriptional level, as shown by quantitative real-time PCR and reporter assays. Chromatin immunoprecipitation (ChIP) data further indicated that binding of the cAMP response element-binding (CREB) protein and activating protein-1 (AP-1) to the MMP-2 promoter diminished at the highest dosage level of Selaginellatamariscina. The DNA-binding activity of specificity protein 1 (SP-1) to the MMP-9 promoter was also suppressed at the same concentration. Selaginellatamariscina did not affect the mitogen-activated protein kinase signaling pathway, but did inhibit the effects of gelatinase by reducing the activation of serine-threonine kinase Akt. CONCLUSIONS: These results demonstrate that Selaginellatamariscina may be a potent adjuvant therapeutic agent in the prevention of oral cancer.

Antimetastatic effects of Terminalia catappa L. on oral cancer via a down-regulation of metastasis-associated proteases.

The incidence and mortality of oral cancer in Taiwan have been increased during the last decade, which could be mainly resulted from the difficulty in treatment related to metastasis. As a potential and popular folk medicine, Terminalia catappa leaves have been proven to possess various biological benefits including anti-cancer activities. However, the detailed effects and molecular mechanisms of T. catappa leaves on the metastasis of oral cancer cells were still unclear. Thus, SCC-4 oral cancer cells were subjected to a treatment with ethanol extracts of T. catappa leaves (TCE) and then analyzed for the effect of TCE on the migration and invasion. Modified Boyden chamber assays revealed that TCE treatment significantly inhibited the cell migration/invasion capacities of SCC-4 cells. Furthermore, results of zymography and western blotting showed that activities and protein levels of MMP-2, MMP-9 and u-PA were all inhibited by TCE. Further studies indicated that TCE may inhibit phosphorylation of ERK1/2, JNK1/2 and Akt while the expression of nuclear protein NF-kappaB, c-Jun and c-Fos were inhibited as well. EMSA assay revealed that the DNA-binding activity with AP-1 and NF-kappaB was also decreased by TCE. In conclusion, TCE may serve as a powerful chemopreventive agent against oral cancer metastasis.