Licochalcone A (LicA), an estrogenic flavonoid, induces apoptosis in multiple types of cancer cells. In this study, the molecular mechanisms underlying the anti-cancer effects of LicA were investigated in HepG2 human hepatocellular carcinoma cells. LicA induced apoptotic cell death, activation of caspase-4, -9, and -3, and expression of endoplasmic reticulum (ER) stress-associated proteins, including C/EBP homologous protein (CHOP). Inhibition of ER stress by CHOP knockdown or treatment with the ER stress inhibitors, salubrinal and 4-phenylbutyric acid, reduced LicA-induced cell death. LicA also induced reactive oxygen species (ROS) accumulation and the anti-oxidant N-acetylcysteine reduced LicA-induced cell death and CHOP expression. In addition, LicA increased the levels of cytosolic Ca(2+), which was blocked by 2-aminoethoxydiphenyl borate (an antagonist of inositol 1,4,5-trisphosphate receptor) and BAPTA-AM (an intracellular Ca(2+) chelator). 2-Aminoethoxydiphenyl borate and BAPTA-AM inhibited LicA-induced cell death. Interestingly, LicA induced phosphorylation of phospholipase Cγ1 (PLCγ1) and inhibition of PLCγ1 reduced cell death and ER stress. Moreover, the multi-targeted receptor tyrosine kinase inhibitors, sorafenib and sunitinib, reduced LicA-induced cell death, ER stress, and cytosolic Ca(2+) and ROS accumulation. Finally, LicA induced phosphorylation of vascular endothelial growth factor receptor 2 (VEGFR2) and c-Met receptor and inhibition of both receptors by co-transfection with VEGFR2 and c-Met siRNAs reversed LicA-induced cell death, Ca(2+) increase, and CHOP expression. Taken together, these findings suggest that induction of ER stress via a PLCγ1-, Ca(2+)-, and ROS-dependent pathway may be an important mechanism by which LicA induces apoptosis in HepG2 hepatocellular carcinoma cells.

No abstract

Apicidin, a fungal metabolite that functions as a histone deacetylase inhibitor, induces apoptosis in cancer cells. We investigated the molecular mechanisms of the anti-cancer effects of apicidin in mouse Neuro-2a neuroblastoma cells. Apicidin induced apoptotic cell death and activation of caspase-12, -9, and -3. Apicidin induced expression of endoplasmic reticulum (ER) stress-associated proteins, including CCAAT/enhancer binding protein homologous protein (CHOP), cleavage of activating transcription factor 6α, and phosphorylation of eukaryotic initiation factor 2α. Inhibition of ER stress by CHOP knockdown or using the ER stress inhibitors, salubrinal and 4-phenylbutyric acid, reduced apicidin-induced cell death. Apicidin induced reactive oxygen species accumulation and mitochondrial membrane potential loss. An antioxidant, N-acetyl cysteine, reduced apicidin-induced cell death, CHOP expression, and mitochondrial dysfunction. In addition, apicidin increased cytosolic Ca(2+), which was blocked by 2-aminoethoxydiphenyl borate, an antagonist of inositol 1,4,5-trisphosphate receptor, and BAPTA-AM, an intracellular Ca(2+) chelator. 2-Aminoethoxydiphenyl borate and BAPTA-AM inhibited apicidin-induced cell death and ER stress. Interestingly, apicidin induced phosphorylation of phospholipase Cγ1 (PLCγ1) and epidermal growth factor receptor (EGFR), and inhibition of PLCγ1 and EGFR reduced cell death and ER stress. Finally, apicidin-induced histone H3 hyperacetylation and reduction of histone deacetylase 2 mRNA expression were not affected by either a PLCγ1 inhibitor, U73122, or the antioxidant, N-acetyl cysteine. Taken together, the results suggest that apicidin induces apoptosis by ER stress and mitochondrial dysfunction via PLCγ1 activation, Ca(2+) release, and reactive oxygen species accumulation in Neuro-2a neuroblastoma cells.

Objectives : The purpose of this study was to determine the anti-obesity effect and molecular mechanism of YY312, a herbal extract composed of Imperatae Rhizoma, Citri Unshius Pericarpium Immaturus, and Evodiae Fructus, on a high-fat diet-induced animal model and on 3T3-L1 cells. Methods : C57BL/6 mice were fed for 6 weeks with a normal diet or a high-fat diet (HFD). Then they orally administered daily with 300 mg/kg YY312 for next 10 weeks. Body weight and food consumption were recorded weekly and daily, respectively. Tissue weights, serum lipid, and glucose levels were analyzed at the end of the study. Additionally, the effects of YY312 on adipocyte differentiation in 3T3-L1 cells were examined. After differentiating 3T3-L1 cells were treated with YY312, Oil-red O staining, RT-PCR, and Western blotting were performed for lipid accumulation, mRNA expression of adipogenesis gene, and AMP-activated protein kinase (AMPK) phosphorylation, respectively. Results : YY312-administered mice showed a significant reduction of body weights and abdominal adipose tissue weights. YY312 also reduced the serum levels of triglycerides and total cholesterol, compared with the HFD group. Treatment with YY312 inhibited lipid accumulation and blocked expression of adipogenic transcription factors and lipogenesis genes, including peroxisome proliferator-activated receptor γ, CCAT/enhancer binding protein α and fatty acid synthase. YY312 increased AMPK phosphorylation in 3T3-L1 adipocytes.Conclusions : This study showed that herbal extract YY312 has an anti-obesity effect in vitro and in vivo.Thus, YY312 could be developed as a supplement for reduction of body weight gain induced by an HFD.

No abstract