Amentoflavone induces caspase-dependent/-independent apoptosis and dysregulates cyclin-dependent kinase-mediated cell cycle in colorectal cancer in vitro and in vivo.

Colorectal cancer (CRC) is recognized as the third most common malignancy and the second most deadly in highly developed countries. Although the treatment of CRC has improved in the past decade, the mortality rate of CRC is still increasing. Amentoflavone, one of the flavonoids detected in medical plants, is reported to possess potential anticancer properties in various cancers. However, its role in CRC has not been studied. This study aimed to investigate the role and underlying mechanism of amentoflavone on CRC in vitro and in vivo. We identified the cytotoxicity, apoptosis effect, cell cycle alteration, DNA damage induction and tumor progression inhibition of amentoflavone in HT-29 model by using MTT assay, flow cytometry, immunofluorescence (IF) staining, Western blotting and animal experiments. Amentoflavone induced cytotoxicity is caused by triggering G1 arrest, DNA damage and apoptosis in HT-29 cells. The expression of cyclin D1, CDK4 and CDK6 was decreased by amentoflavone; in contrast, the phosphorylation of ATM and CHK2 and the expression of p21 and p27 were increased. The apoptosis induction of amentoflavone in CRC is not only caspase-dependent but also increases EndoG and AIF nuclear translocation in a caspase-independent manner. Importantly, the apoptosis induction of amentoflavone is not affected by the activity of p53 in CRC. Amentoflavone suppressed the progression of CRC by initiating G1 arrest and ATM/CHK2-mediated DNA damage-responsive, caspase-dependent/independent apoptotic effects. We uncovered a novel tumor-inhibitory role of amentoflavone in CRC that is not associated with p53 activity, which may serve as a potential treatment for CRC.

Magnolol Suppresses ERK/NF-κB Signaling and Triggers Apoptosis Through Extrinsic/Intrinsic Pathways in Osteosarcoma.

BACKGROUND/AIM: Osteosarcoma is an aggressive primary malignant bone tumor that occurs in childhood. Although the diagnostic and treatment options have been improved, osteosarcoma confers poor prognosis. Magnolol, an active component of Magnoliae officinalis cortex, has been widely applied in herb medicine and has been shown to have multiple pharmacological activities. However, whether magnolol possesses anti-osteosarcoma capacity remains unknown. MATERIALS AND METHODS: We examined magnolol is cytotoxicity, and whether it regulates apoptosis and oncogene expression using MTT, flow cytometry and Western blotting assays in osteosarcoma cells. RESULTS: Magnolol exerted toxicity towards U-2 OS cells by inducing intrinsic/extrinsic apoptosis pathways. Additionally, treatment of U-2 OS cells with magnolol inhibited MAPK1 mitogen-activated protein kinase 1 (ERK)/Nuclear factor kappa B (NF-B) signaling involved in tumor progression and reduced the expression of anti-apoptotic and metastasis-associated genes. CONCLUSION: Magnolol may induce apoptosis and inactivate ERK/NF-B signal transduction in osteosarcoma cells.

Amentoflavone Inhibits Hepatocellular Carcinoma Progression Through Blockage of ERK/NF-ĸB Activation.

AIM: The aim of the present study was to confirm therapeutic efficacy and find probable mechanism of action of amentoflavone in hepatocellular carcinoma (HCC) in vivo. MATERIALS AND METHODS: Luciferase reporter vector pGL4.50_transfected SK-Hep1 (SK-Hep1/luc2) tumor-bearing mice were treated with vehicle or amentoflavone (100 mg/kg/day by gavage) for 14 days. Tumor growth, amentoflavone toxicity, and extracellular signal-regulated kinase (ERK)/nuclear factor-kappaB (NF-ĸB) signaling in tumor progression were evaluated with digital caliper, bioluminescence imaging, computed tomography, body weight, pathological examination of liver, and immunohistochemistry staining. RESULTS: Amentoflavone significantly inhibited tumor growth, ERK/NF-ĸB activation, and expression of tumor progression-associated proteins as compared to vehicle-treated group. In addition, body weight and liver morphology of mice were not influenced by amentoflavone treatment. CONCLUSION: These results suggest that amentoflavone inhibits HCC progression through suppression of ERK/NF-ĸB signaling.

Amentoflavone Inhibits ERK-modulated Tumor Progression in Hepatocellular Carcinoma In Vitro.

BACKGROUND/AIM: A previous study indicated that amentoflavone inhibits tumor growth of breast cancer. However, the anti-cancer effects and mechanism of amentoflavone in hepatocellular carcinoma (HCC) have not been elucidated. The aim of the present study was to verify the effect of amentoflavone on tumor progression in HCC. MATERIALS AND METHODS: HCC SK-Hep1 cells were treated with different concentrations of amentoflavone or 10 µM PD98059 (extracellular signal-regulated kinases (ERK) inhibitor) for 48 h, respectively, and then cell viability, NF-κB activation, levels of tumor progression-associated proteins, and cell invasion were evaluated with 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), NF-κB reporter gene assay, western blotting, and cell invasion assay. RESULTS: The results demonstrated that both amentoflavone and PD98059 not only significantly reduced cell viability, NF-κB activation, and cell invasion, but also inhibited the expression of tumor progression-associated proteins. In addition, we found that amentoflavone suppresses ERK phosphorylation. CONCLUSION: The results of the present study suggest that amentoflavone down-regulates ERK-modulated tumor progression in HCC.