Acacetin inhibits the invasion and migration of human non-small cell lung cancer A549 cells by suppressing the p38α MAPK signaling pathway

The P110 subunit of PI3-K is a therapeutic target of acacetin in skin cancer

The identification of primary molecular targets of cancer-preventive phytochemicals is essential for a comprehensive understanding of their mechanism of action. In the present study, we investigated the chemopreventive effects and molecular targets of acacetin, a flavonoid found in Robinia p seudoacacia, also known as black locust. Acacetin treatment significantly suppressed epidermal growth factor (EGF)-induced cell transformation. Immunoblot analysis revealed that acacetin attenuated EGF-induced phosphorylation of Akt and p70(S6K), which are downstream effectors of phosphatidylinositol 3-kinase (PI3-K). An immunoprecipitation kinase assay of PI3-K and pull-down assay results demonstrated that acacetin substantially inhibits PI3-K activity by direct physical binding. Acacetin exhibited stronger inhibitory effects against anchorage-dependent and -independent cell growth in cells expressing higher PI3-K activity compared with those exhibiting relatively low PI3-K activity. Binding assay data combined with computational modeling suggest that acacetin binds in an adenosine triphosphate (ATP)-competitive manner with the p110α subunit of PI3-K and interacts with Val828, Glu826, Asp911, Trp760, Ile777, Ile825, Tyr813, Ile910 and Met900 residues. Acacetin was also found to significantly reduce SK-MEL-28 tumor growth and Akt phosphorylation in vivo. Taken together, these results indicate that acacetin is an ATP-competitive PI3-K inhibitor and a promising agent for melanoma chemoprevention.

Flt-1 in colorectal cancer cells is required for the tumor invasive effect of placental growth factor through a p38-MMP9 pathway

Background

Placenta growth factor (PlGF), a dimeric glycoprotein with 53% homology to VEGF, binds to VEGF receptor-1 (Flt-1), but not to VEGF receptor-2 (Flk-1), and may function by modulating VEGF activity. We previously have showed that PlGF displays prognostic value in colorectal cancer (CRC) but the mechanism remains elucidated.

Results

Overexpression of PlGF increased the invasive/migration ability and decreased apoptosis in CRC cells showing Flt-1 expression. Increased migration was associated with increasing MMP9 via p38 MAPK activation. Tumors grew faster, larger; with higher vascularity from PlGF over-expression cells in xenograft assay. In two independent human CRC tissue cohorts, PlGF, MMP9, and Flt-1 expressions were higher in the advanced than the localized disease group. PlGF expression correlated with MMP9, and Flt-1 expression. CRC patients with high PlGF and high Flt-1 expression in tissue had poor prognosis.

Conclusion

PlGF/Flt-1 signaling plays an important role in CRC progression, blocking PlGF/Flt-1 signaling maybe an alternative therapy for CRC.

Diet, nutrients, phytochemicals, and cancer metastasis suppressor genes

The major factor in the morbidity and mortality of cancer patients is metastasis. There exists a relative lack of specific therapeutic approaches to control metastasis, and this is a fruitful area for investigation. A healthy diet and lifestyle not only can inhibit tumorigenesis but also can have a major impact on cancer progression and survival. Many chemicals found in edible plants are known to inhibit metastatic progression of cancer. While the mechanisms underlying antimetastatic activity of some phytochemicals are being delineated, the impact of diet, dietary components, and various phytochemicals on metastasis suppressor genes is underexplored. Epigenetic regulation of metastasis suppressor genes promises to be a potentially important mechanism by which dietary components can impact cancer metastasis since many dietary constituents are known to modulate gene expression. The review addresses this area of research as well as the current state of knowledge regarding the impact of diet, dietary components, and phytochemicals on metastasis suppressor genes.

Mere15, a novel polypeptide from Meretrix meretrix, inhibits adhesion, migration and invasion of human lung cancer A549 cells via down-regulating MMPs

CONTEXT

Mere15 is a novel antitumor polypeptide purified from Meretrix meretrix Linn. (Veneridae). Previous studies have shown that the polypeptide induced cell death via intrinsic mitochondrial pathway.

OBJECTIVE

In the present study, the effects of Mere15 on cell adhesion, migration, invasion, as well as secretion and expression of matrix metalloproteinases (MMPs) were studied in human lung adenocarcinoma A549 cells.

MATERIALS AND METHODS

The effect of Mere15 on cell adhesion, migration and invasion were studied by cell adhesion and transwell assay. The expression of MMPs was determined by gelatin zymography and RT-PCR analysis.

RESULTS

The ability of cell adhesion was decreased by 86.74% at the concentration of 12.0 μg/mL of Mere15. And the migration and invasion of A549 cells were decreased with the inhibition ratio of, 69.22 and 53.84% when treated with 15.0 μg/mL of Mere15. Further study also revealed that treatment of the cancer cells with Mere15 (15.0 μg/mL), the secretion of MMP-2 and MMP-9 were down-regulated with the inhibition ratio of 72.00 and 93.24% and the inhibition rate of mRNA expression of MMP-2 and MMP-9 was 57.54 and 91.22%, respectively.

DISCUSSION AND CONCLUSION

The study demonstrates that Mere15 inhibits tumor growth via both pro-apoptotic and antimetastasis pathways, and the polypeptide has potential to be developed as a multi-target therapeutic agent for the treatment of human lung cancer.

Dietary acacetin reduces airway hyperresponsiveness and eosinophil infiltration by modulating eotaxin-1 and th2 cytokines in a mouse model of asthma

A previous study found that eosinophil infiltration and Th2 cell recruitment are important causes of chronic lung inflammation in asthma. The plant flavonoid acacetin is known to have an anti-inflammatory effect in vitro. This study aims to investigate the anti-inflammatory effect of orally administered acacetin in ovalbumin- (OVA-) sensitized asthmatic mice and its underlying molecular mechanism. BALB/c mice were sensitized by intraperitoneal OVA injection. OVA-sensitized mice were fed acacetin from days 21 to 27. Acacetin treatment attenuated airway hyperresponsiveness and reduced eosinophil infiltration and goblet cell hyperplasia in lung tissue. Additionally, eotaxin-1- and Th2-associated cytokines were inhibited in bronchoalveolar lavage fluid and suppressed the level of OVA-IgE in serum. Human bronchial epithelial (BEAS-2B) cells were used to examine the effect of acacetin on proinflammatory cytokines, chemokines, and cell adhesion molecule production in vitro. At the molecular level, acacetin significantly reduced IL-6, IL-8, intercellular adhesion molecule-1, and eotaxin-1 in activated BEAS-2B cells. Acacetin also significantly suppressed the ability of eosinophils to adhere to inflammatory BEAS-2B cells. These results suggest that dietary acacetin may improve asthma symptoms in OVA-sensitized mice.

Tissue factor/activated factor VIIa induces matrix metalloproteinase-7 expression through activation of c-Fos via ERK1/2 and p38 MAPK signaling pathways in human colon cancer cell

PURPOSE

Increased expression of tissue factor (TF) is associated with tumor invasion and metastasis in human colorectal cancer. We have previously observed that TF/FVIIa upregulates matrix metalloproteinase-7 (MMP-7) expression at the transcriptional level in colon cancer cells. MMP-7 overexpression is believed to play an important role in tumor invasion and metastasis. The aim of this study is to elucidate the molecular mechanisms by which TF/FVIIa induced MMP-7 expression and cell invasion in vitro.

METHODS

Reverse transcription polymerase chain reaction, Western blot, luciferase assay, and chromatin immunoprecipitation (ChIP) were used to determine the potential mechanism and signaling pathways by which TF/FVIIa induced MMP-7 expression and cell invasion in LoVo cells. Small interfering RNA (siRNA) and cell invasion assay was used to examine whether blocking c-Fos expression could abolish FVIIa-mediated upregulation of MMP-7 and cell invasion in vitro.

RESULTS

The results showed that FVIIa induced the upregulation of MMP-7 both at the mRNA and protein levels in a time- and dose-dependent manner and increased the invasive behavior of LoVo cells. FVIIa enhanced the promoter activity of MMP-7, and the activator protein-1 (AP-1) binding site was responsible for the activation. Site mutation of the AP-1 binding site in the promoter almost completely abolished FVIIa-mediated response. Furthermore, ChIP assay confirmed that FVIIa promoted the direct binding of c-Fos with the MMP-7 promoter in vivo. FVIIa also induced the expression and nuclear accumulation of the AP-1 subunit c-Fos. siRNA-mediated knockdown of c-Fos eliminated FVIIa-stimulated MMP-7 expression and cell migration in vitro. In addition, selective mitogen-activated protein kinase (MAPK) kinase (MEK1/2) inhibitor (PD98059) and p38 MAPK inhibitor SB203580 suppressed MMP-7 upregulation induced by FVIIa.

CONCLUSIONS

Our data suggest that a novel TF/FVIIa/MAPK/c-Fos/MMP-7 axis plays an important role in modulating the invasion of colon cancer cells and blockage of this pathway holds promise to treat colon cancer metastasis.

Oral intake of hydrogen-rich water inhibits intimal hyperplasia in arterialized vein grafts in rats

AIMS

Arterialized vein grafts often fail due to intimal hyperplasia. Hydrogen potently protects organs and cells from many insults via its anti-inflammatory and antioxidant properties. We investigated the efficacy of oral administration of hydrogen-rich water (HW) for prevention of intimal hyperplasia.

METHODS AND RESULTS

The inferior vena cava was excised, stored in cold Ringer solution for 2 h, and placed as an interposition graft in the abdominal aorta of syngeneic Lewis rats. HW was generated by immersing a magnesium stick in tap water (Mg + 2H(2)O → Mg (OH)(2) + H(2)). Beginning on the day of graft implantation, recipients were given tap water [regular water (RW)], HW or HW that had been subsequently degassed water (DW). Six weeks after grafting, the grafts in the rats given RW or DW had developed intimal hyperplasia, accompanied by increased oxidative injury. HW significantly suppressed intimal hyperplasia. One week after grafting, the grafts in HW-treated rats exhibited improved endothelial integrity with less platelet and white blood cell aggregation. Up-regulation of the mRNAs for intracellular adhesion molecules was attenuated in the vein grafts of the rats receiving HW. Activation of p38 mitogen-activated protein kinase, matrix metalloproteinase (MMP)-2, and MMP-9 was also significantly inhibited in grafts receiving HW. In rat smooth muscle cell (A7r5) cultures, hydrogen treatment for 24 h reduced smooth muscle cell migration.

CONCLUSION

Drinking HW significantly reduced neointima formation after vein grafting in rats. Drinking HW may have therapeutic value as a novel therapy for intimal hyperplasia and could easily be incorporated into daily life.

Acacetin inhibits VEGF expression, tumor angiogenesis and growth through AKT/HIF-1α pathway

Acacetin (5,7-dihydroxy-4'-methoxyflavone) is a flavone compound, some of which have anti-cancerous effects. Vascular endothelial growth factor (VEGF) plays an important role in angiogenesis and tumor growth. In this study, we found that acacetin decreased the steady level of VEGF mRNA level and inhibited VEGF transcriptional activation. To further determine the potential mechanism of acacetin in inhibiting VEGF expression, we showed that acacetin inhibited HIF-1α expression and AKT activation. Over-expression of HIF-1α or AKT restored acacetin-decreasing VEGF transcriptional activation, indicating that AKT and HIF-1 are the essential downstream targets of acacetin for inhibiting VEGF expression in the cells. Moreover, acacetin significantly inhibited ovarian cancer cell-induced angiogenesis and tumor growth in vivo through inhibiting HIF-1α and VEGF expression. Acacetin did not change HIF-1α mRNA level, but inhibited HIF-1α protein level through increasing its degradation and decreasing its stability. These results indicate that acacetin may be a useful natural compound for ovarian cancer prevention and treatment.