Anti-Ischemic Effects of PIK3IP1 Are Mediated through Its Interactions with the ETA-PI3Kγ-AKT Axis.

Oxidative stress, caused by the accumulation of reactive oxygen species (ROS) during acute myocardial infarction (AMI), is one of the main factors leading to myocardial cell damage and programmed cell death. Phosphatidylinositol-3-kinase-AKT (PI3K-AKT) signaling is essential for regulating cell proliferation, differentiation, and apoptosis. Phosphoinositide-3-kinase (PI3K)-interacting protein 1 (PIK3IP1) is an intrinsic inhibitor of PI3K in various tissues, but its functional role during AMI remains unknown. In this study, the anti-ischemic role of PIK3IP1 in an in vitro AMI setting was evaluated using H9c2 cells. The MTT assay demonstrated that cell viability decreased significantly via treatment with H2O2 (200-500 µM). The TUNEL assay results revealed substantial cellular apoptosis following treatment with 200 µM H2O2. Under the same conditions, the expression levels of hypoxia-inducible factor (HIF-1α), endothelin-1 (ET-1), bcl-2-like protein 4 (BAX), and cleaved caspase-3 were elevated, whereas those of PIK3IP1, LC3II, p53, and Bcl-2 decreased significantly. PIK3IP1 overexpression inhibited H2O2-induced and PI3K-mediated apoptosis; however, PIK3IP1 knockdown reversed this effect, suggesting that PIK3IP1 functions as an anti-apoptotic molecule. To identify both the upstream and downstream molecules associated with PIK3IP1, ET-1 receptor type-specific antagonists (BQ-123 and BQ-788) and PI3K subtype-specific antagonists (LY294002 and IPI-549) were used to determine the participating isoforms. Co-immunoprecipitation was performed to identify the binding partners of PIK3IP1. Our results demonstrated that ROS-induced cardiac cell death may occur through the ETA-PI3Kγ-AKT axis, and that PIK3IP1 inhibits binding with both ETA and PI3Kγ. Taken together, these findings reveal that PIK3IP1 plays an anti-ischemic role by reducing the likelihood of programmed cell death via interaction with the ETA-PI3Kr-AKT axis.

A novel system-level approach using RNA-sequencing data identifies miR-30-5p and miR-142a-5p as key regulators of apoptosis in myocardial infarction.

This study identified microRNAs involved in myocardial infarction (MI) through a novel system-level approach using RNA sequencing data in an MI mouse model. This approach involved the extraction of DEGs and DEmiRs from RNA-seq data in sham and MI samples and the subsequent selection of two miRNAs: miR-30-5p (family) and miR-142a-5p, which were downregulated and upregulated in MI, respectively. Gene Set Enrichment Analysis (GSEA) using the predicted targets of the two miRNAs suggested that apoptosis is an essential gene ontology (GO)-associated term. In vitro functional assays using neonatal rat ventricular myocytes (NRVMs) demonstrated that miR-30-5p is anti-apoptotic and miR-142a-5p is pro-apoptotic. Luciferase assays showed that the apoptotic genes, Picalm and Skil, and the anti-apoptotic genes, Ghr and Kitl, are direct targets of miR-30-5p and miR-142a-5p, respectively. siRNA studies verified the results of the luciferase assays for target validation. The results of the system-level high throughput approach identified a pair of functionally antagonistic miRNAs and their targets in MI. This study provides an in-depth analysis of the role of miRNAs in the pathogenesis of MI which could lead to the development of therapeutic tools. The system-level approach could be used to identify miRNAs involved in variety of other diseases.

Effects of Viola mandshurica on Atherosclerosis and Hepatic Steatosis in ApoE[Formula: see text] via the AMPK Pathway.

Atherosclerosis was previously thought to be a disease that primarily involves lipid accumulation in the arterial wall. In this report, we investigated the effect of Viola mandshurica W. Becker (V. mandshurica) water extract on atherosclerosis in apolipoprotein E deficient (ApoE[Formula: see text]) mice. The administration of V. mandshurica to high-fat diet-fed mice reduced body weight, liver weight, and serum levels of lipids (total cholesterol, low-density lipoprotein-cholesterol, triglycerides), glucose, alanine transaminase, and aspartate transaminase. Histopathologic analyses of the aorta and liver revealed that V. mandshurica attenuated atherosclerotic lesions and reduced lipid accumulation, inflammatory responses and fatty acid synthesis. V. mandshurica also increased phosphorylation of adenosine monophosphate-activated protein kinase (AMPK), thereby reducing acetyl-CoA carboxylase (ACC) in liver tissue and inhibiting sterol regulatory element-binding protein 1c (SREBP-1c). V. mandshurica reduced protein expression levels of adhesion molecules (intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and E-selectin) as well as ACC, fatty acid synthase, and SREBP-1c. In addition, quantitative analysis of V. mandshurica by high-performance liquid chromatography revealed the presence of esculetin and scopoletin. Esculetin and scopoletin reduced adhesion molecules in human aortic smooth muscle cells. Our results indicate that the anti-atherosclerotic effects of V. mandshurica may be associated with activation of the AMPK pathway. Therefore, AMPK-dependent phosphorylation of SREBP-1c by V. mandshurica may be an effective therapeutic strategy for combatting atherosclerosis and hepatic steatosis.

The Korean herbal medicine, Do In Seung Gi-Tang, attenuates atherosclerosis via AMPK in high-fat diet-induced ApoE(-/-) mice.

BACKGROUND: Do In Seung Gi-Tang (DISGT) is an herbal mixture of traditional Korean medicine that is composed of Rheum undulatum Linne, Prunus Persica (L.) Batsch, Conyza canadensis L., Cinnamomum Cassia Presl, and Glycytthiza uralensis Fischer (8: 6: 4: 4: 4 ratio). We investigated the effect of DISGT on vascular inflammation and lipid accumulation in apolipoprotein E-deficient (ApoE(-/-)) mice. METHODS: ApoE(-/-) mice that were fed a high-fat diet (HFD) were treated with DISGT (300 mg/kg/day) or statin (10 mg/kg/day) for 16 weeks. Serum lipid levels were analyzed. Oil Red O staining was used to evaluate atherosclerotic lesions and lipid accumulation in the aorta and liver, respectively. The expression of adhesion molecules (intercellular adhesion molecule-1 [ICAM-1], vascular cell adhesion molecule-1 [VCAM-1], and E-selectin), fatty acid synthase (FAS), adenosine monophosphate-activated protein kinase (AMPK), and acetyl-coA carboxylase (ACC) in the aorta or liver tissues was measured by western blot analysis. Lipid synthesis and inflammatory responses were assessed by immunohistochemistry and hematoxylin & eosin staining, respectively. RESULTS: Treatment of HFD-fed mice with DISGT significantly lowered body weight, liver weight, and the levels of lipids, including total cholesterol, low-density lipoprotein-cholesterol, and triglycerides. Glucose levels were also lowered. In the aorta, DISGT attenuated atherosclerotic lesions and reduced the expression of ICAM-1, VCAM-1, and E-selectin. Moreover, DISGT decreased lipid accumulation, inflammatory responses, and FAS levels, and it activated AMPK and reduced ACC expression in liver tissues. CONCLUSIONS: The beneficial, anti-lipolytic, and anti-inflammatory effects of DISGT were mediated by the AMPK pathway. As a result, the expression of inflammatory factors was reduced. Our data provide evidence that DISGT may have strong therapeutic potential in treating vascular diseases, such as atherosclerosis.

Induction of mitochondria-dependent apoptosis in HepG2 human hepatocellular carcinoma cells by timosaponin A-III.

Timosaponin A-III (TSA-III), a saponin isolated from the rhizome of Anemarrhena asphodeloides, exhibits potent cytotoxicity and has the potential to be developed as an anticancer agent. However, the molecular mechanism underlying the anticancer activity of TSA-III has not been fully elucidated. In this study, the apoptotic effects of TSA-III were investigated in HepG2 cells. Treatment with TSA-III significantly inhibited cell growth in a concentration- and time-dependent manner by inducing apoptosis in HepG2 cells. This induction was associated with increased fluorescence intensity of Annexin V-FITC, activation of caspases, and altered expression of inhibitor of apoptosis protein (IAP) family members. In addition, TSA-III mediated mitochondrial dysfunction with the release of HtrA2/Omi, Smac/Diablo, and cytochrome c. These findings suggest that TSA-III induces mitochondria-mediated and caspase-dependent apoptosis in HepG2 cells by altering expression of the IAP family. Thus, TSA-III could possibly be used to treat other types of cancer with similar pathologic mechanisms.

Deep sequencing-generated modules demonstrate coherent expression patterns for various cardiac diseases.

As sequencing technology rapidly develops, gene annotations have also become increasingly sophisticated with incorporation of information regarding the temporal-spatial context of alternative splicing patterns, developmental stages, and tissue specificity. The present study aimed to identify the heart-enriched genes based on next-generation sequencing data and to investigate the gene modules demonstrating coherent expression patterns for various cardiac disease-related perturbations. Seven gene modules, including 382 heart-enriched genes, were identified. At least two modules containing differentially expressed genes were experimentally confirmed to be highly sensitive to various cardiac diseases. Transcription factors regulating the gene modules were then analyzed based on knowledgebase information; the expression of eight transcription factors changed significantly during pressure-overload cardiac hypertrophy, suggesting possible regulation of the modules by the identified transcription factors. Collectively, our results contribute to the classification of heart-enriched genes and their modules and would aid in identification of the transcription factors involved in cardiac pathogenesis in the future.

Protective activity ethanol extract of the fruits of Illicium verum against atherogenesis in apolipoprotein E knockout mice.

BACKGROUND: Illicium verum Hook. fil. Illiciaceae (Illicium v.) has been traditionally used in herbal medicine for treating many inflammatory diseases, including skin inflammation and rheumatism. We investigated its use as a preventive agent against inflammatory and vascular diseases in a murine model of atherosclerosis using apolipoprotein E-knockout (ApoE(-/-)) mice fed on a high-fat diet (HFD). METHODS: We investigated the effect of Illicium v. on cytotoxicity, NF-κB activity, and adhesion molecule expression in TNF-α--stimulated HASMCs (Human Aortic smooth muscle cells). ApoE(-/-)mice, fed a HFD and treated daily for 12 weeks by oral administration of either Illicium v. (100 or 200 mg/kg) or atorvastatin (10 mg/kg), were evaluated for atherosclerotic lesions and inflammatory responses by performing Oil red O and iNOS staining, respectively. Expression of inflammatory cytokines (i.e., NF-κB, TNF-α, IL-1ß, COX, IκB-α, Iκκ-α/ß) and adhesion molecules in the aorta were measured by western blot analysis. RESULTS: In TNF-α-stimulated HASMCs, Illicium v. treatment decreased NF-κB transcriptional activity, and NF-κB protein levels were reduced in a dose-dependent manner over a range of 10-100 µg/mL Illicium v. Also, Illicium v. attenuated the expression of adhesion molecules that are responsible for inflammation in these cells. In animal experiments, treatment with Illicium v. or atorvastatin counteracted the characteristic changes in body weight, blood pressure, and lipid levels seen in HFD-fed ApoE(-/-) mice. In addition, Illicium v. treatment reduced aortic atherosclerotic plaque lesions and the immunoreactivity of iNOS activation. The aortic expression of inflammatory adhesion molecules and cytokines (TNF-α, IL-1ß, NF-κB, COX, IκB-α, Iκκ-α/ß), which is characteristic of HFD-fed ApoE(-/-) mice, was attenuated by 12-week treatment with daily oral administration of Illicium v. or atorvastatin, and the most potent effect was seen with the herbal tincture. CONCLUSIONS: The beneficial effects of Illicium v. are consistent with a significant decrease in the iNOS-mediated inflammatory response, resulting in reduction of inflammation-associated gene expression. Treatment with Illicium v. may be the basis of a novel therapeutic strategy for hyperlipidemia-atherosclerosis.

Anti-metastatic effects of Rheum Palmatum L. extract in human MDA-MB-231 breast cancer cells.

Rheum palmatum L. (RP) has been widely used in traditional medicine for the treatment of various diseases in Asian countries. The molecular mechanism of its anti-metastasis effect remains elusive. The present study assessed the effect of RP ethanol extract (RPE) on the highly metastatic human MDA-MB-231 breast cancer cells in vitro. At a non-toxic concentration, RPE inhibited migration, motility and invasion in a concentration-dependent manner. To investigate the mechanisms involved, real-time PCR and Western blot analyses were performed. Results showed that RPE down-regulated the levels of extracellular matrix degradation-associated proteins, including MMP-2/-9, uPA and uPAR, and up-regulated PAI-1. In addition, RPE affected NF-κB by degrading IkBα, and affected the mitogen-activated protein kinase signal transduction pathway by depressing the activation of p38, ERK and Akt. These results suggest that RPE has potential anti-metastatic activity and warrants further investigation.

Pik3ip1 modulates cardiac hypertrophy by inhibiting PI3K pathway.

Cardiac hypertrophy is an adaptive response to various physiological and pathological stimuli. Phosphoinositide-3 kinase (PI3K) is a highly conserved lipid kinase involved in physiological cardiac hypertrophy (PHH). PI3K interacting protein1 (Pik3ip1) shares homology with the p85 regulatory subunit of PI3K and is known to interact with the p110 catalytic subunit of PI3K, leading to attenuation of PI3K activity in liver and immune cells. However, the role of Pik3ip1 in the heart remains unknown. In the present study, the effects of Pik3ip1 on cardiac hypertrophy were examined. We found that the expression level of Pik3ip1 was markedly higher in cardiomyocytes than in fibroblasts. The interaction of Pik3ip1 with the p110a subunit of PI3K in the heart was identified by immunoprecipitation using neonatal rat cardiomyocytes (NRCM). Approximately 35% knockdown of Pik3ip1 was sufficient to induce myocardial hypertrophy. Pik3ip1 deficiency was shown to lead to activation of PI3K/protein kinase B (AKT)/ mammalian target of rapamycin (mTOR) signaling pathway, increasing protein synthesis and cell size. However, adenovirus-mediated overexpression of Pik3ip1 attenuated PI3K-mediated cardiac hypertrophy. Pik3ip1 was upregulated by PHH due to swimming training, but not by pathological cardiac hypertrophy (PAH) due to pressure-overload, suggesting that Pik3ip1 plays a compensatory negative role for PHH. Collectively, our results elucidate the mechanisms for the roles of Pik3ip1 in PI3K/AKT signaling pathway.

Ampelopsis japonica ethanol extract suppresses migration and invasion in human MDA­MB­231 breast cancer cells.

Ampelopsis japonica (AJ) is a well­known traditional oriental herb with anti­inflammatory and anticancer activities. However, the molecular mechanisms by which AJ inhibits metastasis in breast cancer cells remain to be elucidated. The aim of the present study was to investigate the effects of AJ ethanol extract (EAJ) on highly metastatic human MDA­MB­231 breast cancer cells in vitro. AJ was extracted and chemically characterized. Cell proliferation was determined using a CCK­8 assay and migration was detected using a wound healing motility assay. A Transwell assay was used to evaluate the invasion and metastatic capabilities of the MDA­MB­231 cells. In addition, the mRNA expression levels of metalloproteinase (MMP)­2 and MMP­9 and tissue inhibitors of metalloproteinases (TIMP)­1 and TIMP­2 were evaluated using reverse transcription quantitative polymerase chain reaction in vitro. The results of the present study characterized the signaling cascades that mediated the antimetastatic activity of AJ in the human MDA­MB­231 breast cancer cell line. EAJ significantly suppressed the migration and invasion of MDA­MB­231 cells in vitro and inhibited the expression of metalloproteinase (MMP)­2 and MMP­9. These findings identified the biological activity of EAJ in an in vitro model of cancer metastasis and provided a rationale for further investigation.

Anti-metastatic effect of Smilax china L. extract on MDA-MB-231 cells.

Cancer metastases are not always cured by chemotherapy. Conventional and alternative drugs, including Chinese herbal remedies, have been developed to target metastatic cancer cells. Smilax china L. (SCL), a member of the Smilacaceae family, exerts anti-inflammatory, detoxification and anti-cancer effects. However, the effect of SCL on breast cancer cell metastasis and the underlying mechanisms are yet to be elucidated. The aim of this study was to investigate the effect of a SCL ethanol extract (SCLE) on the proliferation and migration of MDA-MB-231 human breast cancer cells, as well as the expression of urokinase plasminogen activator (uPA), uPA receptor (uPAR) and tissue inhibitors of metalloproteinases (TIMPs). Cell proliferation was assessed using the Cell Counting Kit­8 and cell migration was determined by wound healing assay. Quantitative polymerase chain reaction was performed to quantify the mRNA levels of uPA, uPAR and TIMPs. SCLE markedly inhibited the proliferation and migration of MDA-MB-231 cells, and reduced the mRNA levels of the extracellular matrix (ECM) degradation-associated molecules uPA, uPAR. By contrast, SCLE significantly increased the mRNA levels of TIMP1 and TIMP2. These findings show that SCLE exerts an anti-metastatic effect on human breast cancer cells, which may involve the modulation of ECM degradation.

An ethyl acetate fraction derived from Houttuynia cordata extract inhibits the production of inflammatory markers by suppressing NF-кB and MAPK activation in lipopolysaccharide-stimulated RAW 264.7 macrophages.

BACKGROUND: Houttuynia cordata Thunb. (Saururaceae) has been used in traditional medicine for treatment of inflammatory diseases. This study evaluated the anti-inflammatory effects of an ethyl acetate fraction derived from a Houttuynia cordata extract (HCE-EA) on the production of inflammatory mediators and the activation of nuclear factor-κB (NF-κB) and mitogen-activated protein kinases (MAPKs) in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. METHODS: To measure the effects of HCE-EA on pro-inflammatory cytokine and inflammatory mediator's expression in RAW 264.7 cells, we used the following methods: cell viability assay, Griess reagent assay, enzyme-linked immunosorbent assay, real-time polymerase chain reaction and western blotting analysis. RESULTS: HCE-EA downregulated nitric oxide (NO), prostaglandin E2 (PGE2), tumor necrosis factor-α (TNF-α), and interleukin (IL-6) production in the cells, as well as inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression. Furthermore, HCE-EA suppressed nuclear translocation of the NF-κB p65 subunit, which correlated with an inhibitory effect on IκBα (nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha) phosphorylation. HCE-EA also attenuated the activation of MAPKs (p38 and JNK). CONCLUSIONS: Our results suggest that the anti-inflammatory properties of HCE-EA may stem from the inhibition of pro-inflammatory mediators via suppression of NF-κB and MAPK signaling pathways.

Corosolic acid induces apoptotic cell death in human lung adenocarcinoma A549 cells in vitro.

Corosolic acid (CRA), a triterpenoid from medicinal herbs, has been shown to induce apoptosis in several cell lines, with the exception of A549 cells. In this report, we investigated the apoptotic effect and mechanism of CRA in A549 cells. The present study shows that CRA significantly inhibits cell viability in a concentration- and time-dependent manner. Exposure to CRA induces sub-G1 cell cycle arrest and causes apoptotic death in A549 cells. CRA also triggers the activation of caspases and poly(ADP-ribose) polymerase, an effect antagonized by z-vad-fmk. In addition, exposure to CRA leads to a significant increase in the levels of reactive oxygen species (ROS) in A549 cells. Furthermore, exposure to the ROS scavenger N acetylcysteine (NAC)prevents CRA-induced apoptosis, suggesting a role for ROS in CRA-induced apoptosis. ROS are critical regulators of caspase-mediated apoptosis in A549 cells. These results indicate that CRA induces mitochondria-mediated and caspase-dependent apoptosis in A549 cells by altering anti-apoptotic proteins in a ROS-dependent manner.

Topical application of an ethanol extract prepared from Illicium verum suppresses atopic dermatitis in NC/Nga mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Illicium verum is a traditional herbal medicine with anti-inflammatory properties used in Asia. However, its usefulness in the treatment of allergic diseases remains unclear. This study evaluated the anti-inflammatory and antiallergic effects of I. verum extract (IVE) in a mouse model of atopic dermatitis. MATERIALS AND METHODS: We investigated the effects of IVE on compound 48/80-induced histamine release, and phorbol 12-myristate13-acetate and calcium ionophore A23187-stimulated cytokines secretion in MC/9 mast cells. Atopic dermatitis was induced in NC/Nga mice by exposure to extract of house dust mite (Dermatophagoides farinae). After a topical application of IVE on ear and skin lesions, we evaluated the severity of skin symptoms, ear thickness, inflammatory cell infiltration, and serum levels of immunoglobulin E (IgE), histamine, interleukin (IL)-6, and intercellular adhesion molecule (ICAM)-1. In addition, we determined the expression of IL-4, IL-6, tumor necrosis factor (TNF)-α, interferon (IFN)-γ thymus- and activation-regulated chemokine (TARC), regulated on activation, normal T cell expressed and secreted (RANTES), ICAM-1, and vascular cell adhesion molecule (VCAM)-1 in ear tissues. RESULTS: IVE inhibited secretion of histamine, IL-4, IL-6, and TNF-α from mast cells in a dose-dependent manner. Topical application of IVE significantly reduced dermatitis scores, ear thickness, and serum levels of IgE, histamine, IL-6, and ICAM-1. Histopathological analysis demonstrated decreased epidermal thickening and dermal infiltration by inflammatory cells. In the ear lesions, IVE treatment reduced expression of IL-4, IL-6, TNF-α, TARC, RANTES, ICAM-1, and VCAM-1, but not IFN-γ. CONCLUSIONS: These results indicate that IVE inhibits atopic dermatitis-like skin lesions by suppressing the expression of cytokines, chemokines, and adhesion molecules. These results suggest that IVE may be a potential therapeutic candidate for atopic dermatitis.

Inhibitory effects of Drynaria fortunei extract on house dust mite antigen-induced atopic dermatitis in NC/Nga mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Drynaria fortunei (Kunze) J. Sm has been widely used in traditional medicine for the treatment of inflammation, hyperlipidemia, arteriosclerosis, rheumatism, and bone healing. We investigated the anti-inflammatory effects of a 70% ethanol extract of Drynaria fortunei (DFE). MATERIALS AND METHODS: We evaluated the anti-inflammatory effects of topically applied DFE on house dust mite Dermatophargoides farinae-induced atopic dermatitis-like skin lesions in NC/Nga mice. RESULTS: Treatment of NC/Nga mice with DFE reduced the dermatitis score, ear thickness, and serum levels of IgE, IgG1, and IL-6. Histopathological analyses of ear and skin lesions showed inhibition of the thickening of the epidermis and reduced epidermal/dermal infiltration of inflammatory cells. In ear lesions, mRNA expression levels of IL-4, IL-6, and tumor necrosis factor-α were reduced by DFE treatment. CONCLUSIONS: DFE inhibited the development of dermatitis-like skin lesions in NC/Nga mice. These results suggest that DFE may be a therapeutic candidate for the treatment of AD.

Ethanol Extract of Dianthus chinensis L. Induces Apoptosis in Human Hepatocellular Carcinoma HepG2 Cells In Vitro.

Dianthus chinensis L. is used to treat various diseases including cancer; however, the molecular mechanism by which the ethanol extract of Dianthus chinensis L. (EDCL) induces apoptosis is unknown. In this study, the apoptotic effects of EDCL were investigated in human HepG2 hepatocellular carcinoma cells. Treatment with EDCL significantly inhibited cell growth in a concentration- and time-dependent manner by inducing apoptosis. This induction was associated with chromatin condensation, activation of caspases, and cleavage of poly (ADP-ribose) polymerase protein. However, apoptosis induced by EDCL was attenuated by caspase inhibitor, indicating an important role for caspases in EDCL responses. Furthermore, EDCL did not alter the expression of bax in HepG2 cells but did selectively downregulate the expression of bcl-2 and bcl-xl, resulting in an increase in the ratio of bax:bcl-2 and bax:bcl-xl. These results support a mechanism whereby EDCL induces apoptosis through the mitochondrial pathway and caspase activation in HepG2 cells.

Agrimonia pilosa ethanol extract induces apoptotic cell death in HepG2 cells.

ETHNOPHARMACOLOGICAL RELEVANCE: Agrimonia pilosa (AP) has been used as a traditional herbal medicine for treating various cancers and diseases in Asian countries. MATERIALS AND METHODS: Cell viability along with caspase-3/-7, caspase-8 and caspase-9 activity were measured to detect apoptosis. The activity of the apoptotic factors bcl-2, bcl-xl, mcl-1, XIAP, BID, BIK, caspase-3, caspase-9 and PARP were measured by Western blotting. FACS analysis was used to analyze the cell cycle. RESULTS: APE inhibited the proliferation of HepG2 cells. Growth inhibition was associated with increased caspase activity and sub-G1 apoptotic fractions. When we measured the affect of APE on intracellular signaling, APE stimulated the apoptotic factors bcl-2, bcl-xl, mcl-1, XIAP, BID, BIK, caspase-3, caspase-9 and PARP in HepG2 cells. CONCLUSIONS: The results indicate that APE induces programmed cell death (apoptosis) in HepG2 cells and demonstrates one of the mechanisms underlying the therapeutic effects of the extract reported in previous studies.