Two new alkaloids isolated from Dictamnus dasycarpus Turcz.

Two new quinoline alkaloids (1-2) together with twenty-two known alkaloids (3-24) were isolated and identified from Dictamnus dasycarpus Turcz. Compounds 6-7, 9, 11, 15-16, 19 and 24 were isolated from D. dasycarpus for the first time. The structures of all compounds were characterised by spectroscopic methods (1D, 2D NMR and HRESIMS). The anti-proliferative activity was mediated by the arrest of three human cancer cell lines (SW982, HepG2 and A549) of all the compounds that were evaluated by CCK-8 assay.

Protective effect and mechanism of baicalin on lung inflammatory injury in BALB/cJ mice induced by PM2.5.

The public health harms caused by fine particulate matter (PM2.5) have become a global focus, with PM2.5 exposure recognized as a critical risk factor for global morbidity and mortality. Chronic inflammation is the common pathophysiological feature of respiratory diseases induced by PM2.5 and is the most critical cause of all these diseases. However, presently there is a lack of effective preventive and therapeutic approaches for inflammatory lung injuries caused by PM2.5 exposure. Baicalin is a herb-derived effective flavonoid compound with multiple health benefits. This study established a murine lung inflammatory injury model via inhalation of PM2.5 aerosols. The data showed that after baicalin intervention, lung injury pathological score of baicalin (4.16 ± 0.54, 3.33 ± 0.76, 4.00 ± 0.45) and claricid (3.00 ± 0.78) treatments were markedly lower than PM2.5-treated mice (6.17 ± 0.31), and pathological damage was alleviated. Compared to the PM2.5 group, the spleen and lung indexes in the baicalin and claricid groups were significantly reduced. The inflammatory cytokines of TNF-α, IL-18, and IL-1ß in serum, alveolar lavage fluid, and lung tissue were significantly decreased in the baicalin and claricid groups. The expressions of inflammatory pathway-related genes and proteins HMGB1, NLRP3, ASC, and caspase-1 were up-regulated in the PM2.5 group. The expressions of these genes and proteins were significantly decreased following baicalin treatment. The lung function indicators showed that the MV (65.94 ± 8.19 mL), sRaw (1.79 ± 0.08 cm H2O.s), and FRC (0.52 ± 0.01 mL) in the PM2.5 group were higher than in the control and baicalin groups, and respiratory function was improved by baicalin. PM2.5 exposure markedly altered the bacterial composition at the genus level. The dominant flora relative abundances of uncultured_bacterium_f_Muribaculaceae, Streptococcus, and Lactobacillus, were decreased from the control group (9.20%, 8.53%, 6.21%) to PM2.5 group (6.26%, 5.49%, 4.77%), respectively. Following baicalin intervention, the relative abundances were 9.72%, 6.65%, and 3.57%, respectively. Therefore, baicalin could potentially prevent and improve mice lung inflammatory injury induced by PM2.5 exposure. Baicalin might provide a protective role by balancing oropharyngeal microbiota and affecting the expression of the HMGB1/Caspase1 pathway.

Two new terpenes from the aerial parts of Clematis chinensis Osbeck.

Two new acyclic sesquiterpenoids (1-2) and fourteen known monocyclic monoterpenoids (3-16) were isolated from the aerial parts of Clematis chinensis Osbeck. All compounds were isolated from C. chinensis for the first time. The structures of all compounds were characterized by spectroscopic methods (1 D, 2 D NMR and HRESIMS). In-vitro cytotoxic activity against two human cancer cell lines (MGC-803 and Ishikawa) of all the compounds were evaluated by CCK-8 assay.

Surgical results of infected preauricular sinus: No need for delay.

OBJECTIVES: This study was performed to propose the proper surgical timing of infected preauricular sinus (PAS) by comparing surgical results of active infection PAS group (AIPASG) to infection-controlled/or non-infected PAS group (IC/NIPASG). METHODS: Two hundred and twelve patients with PAS who underwent surgical excision using minimal supra-auricular approach by one surgeon (S.N.P) in a tertiary referral center between Apr 1999 and Dec 2016 were enrolled in this study. Medical records of 36 patients of AIPASG at surgical time point and 176 patients of IC/NIPASG were collected and their surgical results were compared. Postoperative wound infection, recurrence, need of drain insertion or external compression dressing and other clinical parameters including age, sex, follow up duration and previous incision & drainage (I&D) history were investigated and statistically compared between two groups. RESULTS: There were no significant differences of various clinical parameters between two groups, except previous I&D history (24 among 36 patients of AIPASG and 12 among 176 patients of NI/ICPASG, P < 0.05). Post-operative immediate but mild wound erythema was observed in 11 among 212 patients with no statistical difference between two groups (4 among 48 ears of AIPASG and 7 among 219 NI/ICPASG, P = 0.105) and was controlled by short-term antibiotics and conservative management. Only 1 patient of NI/ICPASG needed a revision surgery of wound exploration and curettage. No more recurrence of infection during their long-term follow-up period was observed in both groups. CONCLUSION: There was no significant difference in the surgical results of minimal supra-auricular approach of PAS excision between AIPASG and NI/ICPASG. Therefore, we suggest that this surgical technique can be performed even in the infected PAS which does not quickly respond to the conservative treatment.

Apoptotic and Anti-Inflammatory Effects of Eupatorium japonicum Thunb. in Rheumatoid Arthritis Fibroblast-Like Synoviocytes.

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease characterized by synovitis, hyperplasia, and the destruction of bone and cartilage. A variety of immunosuppressive biological agents have been developed because the pathogenesis of RA is related predominantly to the inflammatory response. However, rheumatoid arthritis fibroblast-like synovial cells (RAFLS), which are known to play an important role in RA progression, exhibit resistance to immunosuppressants through cancer-like properties. In this study, we identified a novel therapeutic compound for RA, which reduced inflammation and the abnormal proliferation of RAFLS in natural product library made from Korean native plants. Eupatorium japonicum Thunb. (EJT) extract, a component of the natural product library, most effectively reduced viability through the induction of ROS-mediated apoptosis in a dose-dependent manner. In addition, the increased ROS induced the expression of ATF4 and CHOP, key players in ER stress-mediated apoptosis. Interestingly, EJT extract treatment dose-dependently reduced the expression of IL-1ß and the transcription of MMP-9, which were induced by TNF-α treatment, through the inhibition of NF-κB and p38 activation. Collectively, we found that EJT extract exerted apoptotic effects through increases in ROS production and CHOP expression and exerted anti-inflammatory effects through the suppression of NF-κB activation, IL-1ß expression, and MMP-9 transcription.

Angelica gigas Nakai Has Synergetic Effects on Doxorubicin-Induced Apoptosis.

Natural products are valuable sources for drug discovery because they have a wide variety of useful chemical components and biological properties. A quick reevaluation of the potential therapeutic properties of established natural products was made possible by the recent development of the methodology and improvement in the accuracy of an automated high-throughput screening system. In this study, we screened natural product libraries to detect compounds with anticancer effects using HeLa cells. Of the 420 plant extracts screened, the extract of Angelica gigas Nakai (AGN) was the most effective in reducing cell viability of HeLa cells. Markers of apoptosis, such as exposure of phosphatidylserine and cleavage of caspase-7 and PARP, were increased by treatment with the AGN extract. Treatment of the AGN extract increased expression of PKR as well as ATF4 and CHOP, the unfolded protein response genes. In addition, cotreatment of doxorubicin and the AGN extract significantly increased doxorubicin-induced apoptosis in HeLa cells. Decursin and decursinol angelate, which were known to have anticancer effects, were the main components of the AGN extract. These results suggest that the extract of AGN containing, decursin and decursinol angelate, increases doxorubicin susceptibility.

New role of human ribosomal protein S3: Regulation of cell cycle via phosphorylation by cyclin-dependent kinase 2.

Human ribosomal protein S3 (hRpS3) is a component of the 40S ribosomal subunit that associated in protein synthesis. hRpS3 has additional ribosomal functions such as DNA repair, transcription, metastasis, and apoptosis via interaction with numerous signaling molecules and has different modifications. Cyclin-dependent kinases (CDKs) are heterodimeric serine/threonine protein kinases that regulate cell cycle progression. Among its members, the Cdk1-cyclin B complex is known to control cell progression in the G2/M phase, while Cdk2-cyclin E/A complexes function in G1/S and S/G2 transition. In our previous study, we observed interaction between hRpS3 and Cdk1. The present study investigated the interaction between hRpS3 and Cdk2. Cdk2 phosphorylated hRps3 at amino acid residues S6 and T221 during the S-phase. Furthermore, hRpS3 knockdown delayed cell cycle progression by modulating the expression of cell cycle-related proteins, including cyclin B1 and cyclin E1. These findings suggest that hRpS3 is involved in Cdk2-mediated cell cycle regulation.

MutY DNA Glycosylase Protects Cells From Tumor Necrosis Factor Alpha-Induced Necroptosis.

Numerous studies have implied that mutY DNA glycosylase (MYH) is involved in the repair of post-replicative mispairs and plays a critical role in the base excision repair pathway. Recent in vitro studies have shown that MYH interacts with tumor necrosis factor receptor type 1-associated death domain (TRADD), a key effector protein of tumor necrosis factor receptor-1 (TNFR1) signaling. The association between MYH and TRADD is reversed during tumor necrosis factor alpha (TNF-α)- and camptothecin (CPT)-induced apoptosis, and enhanced during TNF-α-induced survival. After investigating the role of MYH interacts with various proteins following TNF-α stimulation, here, we focus on MYH and TRADD interaction functions in necroptosis and its effects to related proteins. We report that the level of the MYH and TRADD complex was also reduced during necroptosis induced by TNF-α and zVAD-fmk. In particular, we also found that MYH is a biologically important necrosis suppressor. Under combined TNF-α and zVAD-fmk treatment, MYH-deficient cells were induced to enter the necroptosis pathway but primary mouse embryonic fibroblasts (MEFs) were not. Necroptosis in the absence of MYH proceeds via the inactivation of caspase-8, followed by an increase in the formation of the kinase receptor- interacting protein 1 (RIP1)-RIP3 complex. Our results suggested that MYH, which interacts with TRADD, inhibits TNF-α necroptotic signaling. Therefore, MYH inactivation is essential for necroptosis via the downregulation of caspase-8. J. Cell. Biochem. 118: 1827-1838, 2017. © 2017 Wiley Periodicals, Inc.

A triboelectric motion sensor in wearable body sensor network for human activity recognition.

The goal of this study is to design a novel triboelectric motion sensor in wearable body sensor network for human activity recognition. Physical activity recognition is widely used in well-being management, medical diagnosis and rehabilitation. Other than traditional accelerometers, we design a novel wearable sensor system based on triboelectrification. The triboelectric motion sensor can be easily attached to human body and collect motion signals caused by physical activities. The experiments are conducted to collect five common activity data: sitting and standing, walking, climbing upstairs, downstairs, and running. The k-Nearest Neighbor (kNN) clustering algorithm is adopted to recognize these activities and validate the feasibility of this new approach. The results show that our system can perform physical activity recognition with a successful rate over 80% for walking, sitting and standing. The triboelectric structure can also be used as an energy harvester for motion harvesting due to its high output voltage in random low-frequency motion.

Functional interaction between hMYH and hTRADD in the TNF-α-mediated survival and death pathways of HeLa cells.

UNLABELLED: The tumor necrosis factor (TNF) signaling pathway is a classical immune system pathway that plays a key role in regulating cell survival and apoptosis. The TNF receptor-associated death domain (TRADD) protein is recruited to the death domain of TNF receptor 1 (TNFR1), where it interacts with TNF receptor-associated factor 2 (TRAF2) and receptor-interacting protein (RIP) for the induction of apoptosis, necrosis, nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB), and mitogen-activated protein (MAP) kinase activation. In this study, we found that the human MutY homolog (hMYH) interacted with human TRADD (hTRADD) via the C-terminal domain of hMYH. Moreover, under conditions promoting TNF-α-induced cell death or survival in HeLa cells, this interaction was weakened or enhanced, respectively. The interaction between hMYH and hTRADD was important for signaling pathways mediated by TNF-α. Our results also suggested that the hTRADD-hMYH association was involved in the nuclear translocation of NFκB and formation of the TNFR1-TRADD complex. Thus, this study identified a novel mechanism through which the hMYH-hTRADD interaction may affect the TNF-α signaling pathway. IMPLICATIONS: In HeLa cells, the hTRADD-hMYH interaction functioned in both cell survival and apoptosis pathways following TNF-α stimulation.

Phosphorylation of cyclin O, a novel cyclin family protein containing a cyclin-like domain, is involved in the activation of cyclin-dependent kinase 2.

Cell cycles, ordered series of events modulating cell growth and division, are tightly regulated by complexes containing cyclin-dependent kinases (CDKs) and cyclins. Cyclin O is a novel cyclin family protein which interacts with CDK2. However, the molecular effects of cyclin O on the activity of CDK2 have not been fully evaluated. In this study, an interaction between cyclin O and CDK2 was identified by co-immunoprecipitation and the effect of cyclin O on the kinase activity of CDK2 was investigated using cyclin O point mutants. Co-immunoprecipitation was achieved using using HEK293 human embryonic kidney cells which were transiently transfected with vectors expressing cyclin O and CDK2, which revealed that cyclin O interacted with CDK2, particularly with the active form of endogenous CDK2. Cyclin O was expressed as several different bands with molecular weights between 45 and 50 kDa, possibly due to different post-translational modifications. When co-expressed with CDK2, cyclin O appeared as a band with a molecular weight of 50 kDa. Treatment with calf intestinal phosphatase reduced the intensity of the uppermost band. Mass spectroscopic analysis of cyclin O co-expressed with CDK2 revealed that the 81st serine residue of cyclin O was phosphorylated. The in vitro kinase activity of CDK2 phosphorylating histone H1 was markedly increased in the cells overexpressing cyclin O. This activity was reduced in cells overexpressing cyclin O, in which the 81st serine had been replaced with alanine (S81A). These results suggest that cyclin O is a novel cyclin family protein that regulates CDK2 kinase activity, which is mediated by the phosphorylation of the 81st serine residue of cyclin O.

The incidence of deep venous thrombosis after arthroscopically assisted anterior cruciate ligament reconstruction.

PURPOSE: The purpose of our study was to retrospectively assess and analyze the incidence of deep venous thrombosis (DVT) after arthroscopically assisted anterior cruciate ligament reconstruction (ACLR) at our institution. METHODS: We conducted a retrospective analysis of 249 arthroscopic ACLRs performed in our hospital between February 2009 and February 2012. The surgical procedure was standardized in all the patients and was conducted by the same 2 surgeons. Quadrupled hamstring autograft was used in all the patients. No patient was given nonsteroidal anti-inflammatory drugs for the first 2 weeks after surgery. A unilateral contrast venography examination was performed on the third postoperative day. Patients were confined to bed once DVT was confirmed, followed by therapeutic doses of batroxobin. The proportion of patients with DVT was calculated. The significance of the association between clinical factors and postoperative DVT was determined. RESULTS: This study included 171 patients (123 men and 48 women), with a mean age (±SD) of 30.1 ± 10.0 years. DVT was detected in 24 patients (14.0%; 95% confidence interval, 8.8% to 19.3%). Body mass index (BMI), operative time, operator, and duration of tourniquet application were not significant risk factors for DVT. The risk of DVT was significantly higher in patients aged 35 years or older (P < .01). Higher risk for DVT was also identified in female patients (P < .05). Pulmonary embolism did not develop after thrombolytic therapy in any of the 24 patients with DVT after ACLR. CONCLUSIONS: The incidence of DVT in patients who underwent arthroscopic ACLR was 14% in this study. Female patients and those aged 35 years or older have a significantly higher risk of DVT developing after ACLR; thus thromboprophylaxis is advocated in these patients. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Human MutY homolog induces apoptosis in etoposide-treated HEK293 cells.

Etoposide (ETP) treatment of ataxia telangiectasia mutated (ATM) and Rad3-related protein (ATR)-, topoisomerase-binding protein-1 (TopBP1) and human MutY homolog (hMYH)-depleted cells results in a significant reduction in apoptotic signaling. The association between ATR or TopBP1 and hMYH increased following ETP treatment. In hMYH knockdown cells, the interaction between ATR and TopBP1 decreased following ETP treatment. We suggest that hMYH functions as a sensor of ETP-induced apoptosis. The results suggest that in the absence of hMYH, cells are unable to recognize the damage signal and the ATR pathway is not activated.

Arresting cancer proliferation by controlling the surface crystallinity of carbon materials without generating reactive oxygen species.

This study demonstrated that the surface crystallinity of carbon nanostructures is an additional independent factor that should be considered for the inhibition of cancer proliferation without activating reactive oxygen species (ROS). In addition, cytotoxic evaluation of both proliferating cancer cells and fully differentiated nerve cells (i.e. non-proliferative) showed selective cytotoxicity: single-walled and highly crystalline carbon nanostructures aggressively inhibited the proliferation of glioma cancer cells, but exhibited no notable cytotoxicity effects on differentiated nerve cells. Although single-wall carbon nanotubes have been shown to elicit potent proinflammatory responses by means of trigger ROS, our results demonstrated that highly crystalline carbon structures can be utilized as a selective antiproliferative agent against brain tumor cells without increasing the ROS level and without significant cytotoxic effects to adjacent nerve cells.

Palmitate promotes the paracrine effects of macrophages on vascular smooth muscle cells: the role of bone morphogenetic proteins.

Saturated fatty acids are known to activate macrophages and induce vascular inflammation. Although cytokines from activated macrophage influence other vascular cells, the influence of saturated fatty acids on the paracrine effect of macrophages is not fully understood yet. Here we examined the impact of palmitate on the effect of macrophages on vascular smooth muscle cells (SMCs) and their mediators. SMCs proliferation increased significantly after treatment with conditioned media from palmitate-stimulated RAW264.7 cells. SMC migration was found to be greater after treatment with palmitate-conditioned media. SM α-actin and SM22α were decreased in SMCs treated with palmitate-conditioned media. When stimulated with palmitate, RAW264.7 cells secreted more bone morphogenetic protein (BMP)2 and BMP4 into the cell culture media. SMC proliferation, migration, and phenotypic changes were attenuated after treatment of neutralizing antibodies against BMPs or knockdown of BMPs with siRNA. The influences of these proteins were further confirmed by direct treatment of recombinant BMP2 and BMP4 on SMCs. Particularly, the effects of BMPs on SMC migration on phenotypic change were obvious, whereas their effect on SMC proliferation seemed not significant or modest. In conclusion, palmitate promoted macrophages' paracrine effects on SMC proliferation, migration, and phenotypic change. The effect of stimulated macrophages was mediated, at least in part, by BMP2 and BMP4. These results suggest a novel mechanism linking saturated fatty acids and the progression of vascular diseases that is possibly mediated by BMPs from macrophages.

Ubiquitin ligase CHIP induces TRAF2 proteasomal degradation and NF-κB inactivation to regulate breast cancer cell invasion.

Transcriptional factor nuclear factor-kappaB (NF-κB) plays a crucial role in human breast cancer cell invasion and metastasis. The carboxyl terminus of Hsc70-interacting protein (CHIP) is a U-box-type ubiquitin ligase that induces ubiquitination and proteasomal degradation of its substrate proteins. In this study, we investigated the role of CHIP in the NF-κB pathway in the invasion of MDA-MB-231 cells, a highly aggressive breast cancer cell line. We showed that overexpression of CHIP significantly inhibits the invasion of the MDA-MB-231 cells. The overexpression of CHIP suppressed expression of urokinase plasminogen activator (uPA) and matrix metalloproteinase-9 (MMP-9) in MDA-MB-231 cells. Moreover, CHIP strongly inhibited the nuclear localization and the transcriptional activity of NF-κB. The activation of the IkappaB kinase complex (IKK) was also blocked by CHIP overexpression. Importantly, CHIP overexpression resulted in a significant decrease in the level of TNF receptor-associated factor 2 (TRAF2), an upstream key player in the NF-κB pathway. However, the level of TRAF2 was restored after treatment with a proteasome inhibitor, MG-132. Moreover, CHIP overexpression promoted the ubiquitination of TRAF2. We also found cell invasion significantly decreased in cells transfected with TRAF2 small interfering RNA (siRNA). In contrast, when CHIP expression was suppressed by siRNA in poorly invasive MCF-7 cells, cell invasion significantly increased in conjunction with enhanced NF-κB activation and TRAF2 levels. Taken together, these results suggest that CHIP regulates NF-κB-mediated cell invasion via the down-regulation of TRAF2.

Locally synthesized HSP27 in hepatocytes: Is it possibly a novel strategy against human liver ischemia/reperfusion injury?

Ischemia/reperfusion injury (IRI) is a common complication after liver surgery. Approximately 10% of grafts lose function in the early stage after liver transplantation. However, there is no effective way against IRI yet. Heat shock protein 27 (HSP27), a member of the heat shock protein families, is recognized as a protective factor against liver IRI recently. Studies showed that HSP27 can lessen the induction of proinflammatory messenger, reduce neutrophil infiltration, decrease apoptosis (caspase 3 fragmentation and DNA laddering), and reduce disruption of filamentous actin. In addition, Kupffer cells inhibitor- gadolinium chloride can reduce lipid peroxidation and promote hepatocytes regeneration. Herein, we hypothesize that transfecting liver with HSP27 gene accompanied by gadolinium chloride might be a potentially novel treatment against IRI. Compared to passive defense, we firstly suggest positive protection against ischemia/reperfusion injury by hepatocytes automatically.

Induction of apoptotic cell death by synthetic naringenin derivatives in human lung epithelial carcinoma A549 cells.

Although flavonoids, which are both qualitatively and quantitatively one of the largest groups of natural products, exhibit a variety of beneficial health effects, the exact molecular mechanism of the cellular activities is still not fully explained and there currently exists a lack of evidence for any relationship between the structure-activity relationship and apoptosis-inducing activity. In order to determine the importance of the OH group or substitution of the 5 or carbon-7 in the diphenylpropane skeleton of flavonoids, we originally synthesized several modified naringenin derivatives, including 7-O-benzyl naringenin (KUF-1) and 7-O-(MeO-L-Leu-D-Pro-carbonylmethyl) naringenin (KUF-7). Treatment with KUF-1 or KUF-7 resulted in significant apoptosis-inducing effects concomitant with chromatin condensation, caspase activation, and intracellular ROS production. Our data indicate that originally synthesized naringenin derivatives, KUF-1 and KUF-7 differentially regulate the apoptosis of A549 cells via intracellular ROS production coupled with the concomitant activation of the caspase cascade signaling pathway, thereby implying that hydroxylation or substitution at Carbon-7 is critical for the apoptosis-inducing activity of flavonoids.

Genistein-induced apoptosis of human breast cancer MCF-7 cells involves calpain-caspase and apoptosis signaling kinase 1-p38 mitogen-activated protein kinase activation cascades.

The molecular mechanisms of genistein-induced apoptosis of human breast cancer MCF-7 cells were investigated. Genistein showed 50% cell growth inhibition at IC50=27.5+/-0.8 micromol/l in 24 h incubation under 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay conditions. Genistein is known to express both cell growth activity at nanomolar concentrations and anti-cell growth activity at micromolar concentrations. It was found that genistein at 100 micromol/l concentration effectively induced apoptosis of MCF-7 cells in 24 h. Genistein-induced apoptosis involved activation of calpain, caspase 7 and poly(ADP ribose) polymerase. Dantrolene, an inhibitor of Ca release from the endoplasmic reticulum, inhibited genistein-induced activation of calpain and caspase 7, in addition to effectively negating genistein-induced apoptosis. MCF-7 cells treated with genistein also showed increased phosphorylation of p38 mitogen-activated protein kinase, whereas no effect was observed for extracellular signal-regulating kinase 1/2. Phosphorylation of apoptosis signaling kinase 1, an upstream regulator of p38 mitogen-activated protein kinase, was also increased by genistein treatment. Genistein-induced phosphorylation of apoptosis signaling kinase 1 and p38 mitogen-activated protein kinase was diminished by the presence of dantrolene. These results suggest that genistein-induced apoptosis in MCF-7 cells is mediated through calpain-caspase 7 and apoptosis signaling kinase 1-p38 mitogen-activated protein kinase activation cascades that involve Ca release from the endoplasmic reticulum.

Acacetin-induced apoptosis of human breast cancer MCF-7 cells involves caspase cascade, mitochondria-mediated death signaling and SAPK/JNK1/2-c-Jun activation.

The mechanism of acacetin-induced apoptosis of human breast cancer MCF-7 cells was investigated. Acacetin caused 50% growth inhibition (IC50) of MCF-7 cells at 26.4% 0.7% M over 24 h in the MTT assay. Apoptosis was characterized by DNA fragmentation and an increase of sub-G1 cells and involved activation of caspase-7 and PARP (poly-ADP-ribose polymerase). Maximum caspase 7 activity was observed with 100 microM acacetin for 24 h. Caspase 8 and 9 activation cascades mediated the activation of caspase 7. Acacetin caused a reduction of Bcl-2 expression leading to an increase of the Bax:Bcl-2 ratio. It also caused a loss of mitochondrial membrane potential that induced release of cytochrome c and apoptosis inducing factor (AIF) into the cytoplasm, enhancing ROS generation and subsequently resulting in apoptosis. Pretreatment of cells with N-acetylcysteine (NAC) reduced ROS generation and cell growth inhibition, and pretreatment with NAC or a caspase 8 inhibitor (Z-IETD-FMK) inhibited the acacetin-induced loss of mitochondrial membrane potential and release of cytochrome c and AIF. Stress-activated protein kinase/c-Jun NH4-terminal kinase 1/2 (SAPK/ JNK1/2) and c-Jun were activated by acacetin but extracellular-regulated kinase 1/2 (Erk1/2) nor p38 mitogen-activated protein kinase (MAPK) were not. Our results show that acacetin-induced apoptosis of MCF-7 cells is mediated by caspase activation cascades, ROS generation, mitochondria-mediated cell death signaling and the SAPK/JNK1/2-c-Jun signaling pathway, activated by acacetin-induced ROS generation.