Involvement of Mitochondrial Damage and Oxidative Stress in Apoptosis Induced by Betulin Plus Arsenic Trioxide in Neuroblastoma Cells.

BACKGROUND/AIM: Arsenic trioxide (As2O3), a potent toxin in traditional Chinese medicine, has been utilized as an anticancer agent in Chinese culture for over a millennium. Betulin, commonly extracted from the bark of birch trees, has been identified for its pharmacological properties, including antibacterial, anti-inflammatory, antitumor, and antiviral activities. The aim of this study was to determine the efficacy and underlying anticancer signaling cascade induced by As2O3 and betulin in neuroblastoma cells. MATERIALS AND METHODS: SK-N-SH cells were treated with As2O3 with or without betulin. Cell viability and apoptotic signaling were assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, measurement of mitochondrial membrane potential (MMP) loss and reactive oxygen species (ROS), and quantitative western blotting analysis. Student's t-test in addition to one- or two-way analysis of variance was used to examine significant differences between comparison groups. RESULTS: The combined treatment of As2O3 plus betulin was more effective than single treatments in suppressing cell viability and induction of apoptosis, which correlated well with elevated ROS levels. The apoptotic signaling cascade of As2O3 plus betulin was revealed as ROS elevation and relative loss of MMP, leading to the cleavage of caspase-3 and -9. As2O3 plus betulin treatment also reduced the expression of BCL2 apoptosis regulator, BH3-interacting domain death agonist, and BCL2-like-1. CONCLUSION: The novel combination of As2O3 plus betulin has the potential to serve as a practical anti-neuroblastoma drug.

Therapeutic Potential and Mechanisms of Novel Simple O-Substituted Isoflavones against Cerebral Ischemia Reperfusion.

Isoflavones have been widely studied and have attracted extensive attention in fields ranging from chemotaxonomy and plant physiology to human nutrition and medicine. Isoflavones are often divided into three subgroups: simple O-substituted derivatives, prenylated derivatives, and glycosides. Simple O-substituted isoflavones and their glycosides, such as daidzein (daidzin), genistein (genistin), glycitein (glycitin), biochanin A (astroside), and formononetin (ononin), are the most common ingredients in legumes and are considered as phytoestrogens for daily dietary hormone replacement therapy due to their structural similarity to 17-ß-estradiol. On the basis of the known estrogen-like potency, these above isoflavones possess multiple pharmacological activities such as antioxidant, anti-inflammatory, anticancer, anti-angiogenetic, hepatoprotective, antidiabetic, antilipidemic, anti-osteoporotic, and neuroprotective activities. However, there are very few review studies on the protective effects of these novel isoflavones and their related compounds in cerebral ischemia reperfusion. This review primarily focuses on the biosynthesis, metabolism, and neuroprotective mechanism of these aforementioned novel isoflavones in cerebral ischemia reperfusion. From these published works in in vitro and in vivo studies, simple O-substituted isoflavones could serve as promising therapeutic compounds for the prevention and treatment of cerebral ischemia reperfusion via their estrogenic receptor properties and neuron-modulatory, antioxidant, anti-inflammatory, and anti-apoptotic effects. The detailed mechanism of the protective effects of simple O-substituted isoflavones against cerebral ischemia reperfusion might be related to the PI3K/AKT/ERK/mTOR or GSK-3ß pathway, eNOS/Keap1/Nrf-2/HO-1 pathway, TLRs/TIRAP/MyD88/NFκ-B pathway, and Bcl-2-regulated anti-apoptotic pathway. However, clinical trials are needed to verify their potential on cerebral ischemia reperfusion because past studies were conducted with rodents and prophylactic administration.

Promotion of mitochondrial biogenesis via the regulation of PARIS and PGC-1α by parkin as a mechanism of neuroprotection by carnosic acid.

BACKGROUND: Impairment of mitochondrial biogenesis is associated with the pathological progression of Parkinson's disease (PD). Parkin-interacting substrate (PARIS) can be ubiquitinated by parkin and prevents the repression of proliferator-activated receptor gamma coactivator-1-alpha (PGC-1α). PURPOSE: This study investigated whether the neuroprotective mechanism of carnosic acid (CA) from rosemary is mediated via the regulation of PARIS and PGC-1α by parkin. METHODS: The Western blotting and RT-PCR were used to determine protein and mRNA, respectively. To investigate the protein-protein interaction of between PARIS and ubiquitin, the immunoprecipitation assay (IP assay) was utilized. Silencing of endogenous parkin or PGC-1α was performed by using transient transfection of small interfering RNA (siRNA). RESULTS: SH-SY5Y cells treated with 6-hydroxydopamine (6-OHDA) increased PARIS protein, decreased PGC-1α protein, and reduced protein and mRNA of mitochondrial biogenesis-related genes. CA pretreatment reversed the effects of 6-OHDA. By IP assay, the interaction of PARIS with ubiquitin protein caused by CA was stronger than that caused by 6-OHDA. Moreover, knockdown of parkin attenuated the ability of CA to reverse the 6-OHDA-induced increase in PARIS and decrease in PGC-1α expression. PGC-1α siRNA was used to investigate how CA influenced the effect of 6-OHDA on the modulation of mitochondrial biogenesis and apoptosis. In the presence of PGC-1α siRNA, CA could no longer significantly reverse the reduction of mitochondrial biogenesis or the induction of cleavage of apoptotic-related proteins by 6-OHDA. CONCLUSION: The cytoprotective of CA is related to the enhancement of mitochondrial biogenesis by inhibiting PARIS and inducing PGC-1α by parkin. The activation of PGC-1α-mediated mitochondrial biogenesis by CA prevents the degeneration of dopaminergic neurons, CA may have therapeutic application in PD.

Novel Combination of Arsenic Trioxide (As2O3) Plus Resveratrol in Inducing Programmed Cell Death of Human Neuroblastoma SK-N-SH Cells.

AIM: Arsenic trioxide (As2O3), known as pi-shuang and the most toxic compound in traditional Chinese medicine, has been used as an antitumor agent for thousands of years. Resveratrol (3,5,4'-trihydroxy-trans-stilbene) is a natural phenol that has significant anti-bacterial, anti-fungaI and antiaging activities. Our study aimed to examine the combined anticancer effects of As2O3 and resveratrol against human neuroblastoma SK-N-SH cells, and elucidate the underlying intracellular signaling. MATERIALS AND METHODS: SK-N-SH cells were treated with an extremely low-dose (2-4 µM) of As2O3 alone or combined with 75 µg/ml resveratrol for further comparisons. Cell viability, apoptotic signaling as well as synergistic cytotoxic effects were estimated using the MTT assay, microscopy observation, flow cytometric analysis for loss of mitochondrial membrane potential (MMP) and reactive oxygen species (ROS), and typical quantitative western blotting analysis. Student's t-test, and one- and two-way analysis of variance (ANOVA) were used for examination of significant differences. RESULTS: The combined treatment was more effective than single treatment of As2O3 or resveratrol alone in suppressing cell viability, which correlated with the elevation of ROS levels. The intracellular mechanisms of cytotoxicity of As2O3 plus resveratrol were revealed as ROS accumulation and relative decrease of MMP, leading to activation of caspase-3 and -9, but not of caspase-1, -7 and-8. Combination treatment reduced the expression of B-cell lymphoma 2 (BCL2), BH3 interacting domain death agonist (BID), and BCL-x/L. CONCLUSION: Combined treatment at extremely low concentration of two agents from natural products, As2O3 and resveratrol, has high potential as a cocktail of anticancer drugs for neuroblastoma.

Dithiothreitol enhanced arsenic-trioxide-induced cell apoptosis in cultured oral cancer cells via mitochondrial dysfunction and endoplasmic reticulum stress.

Arsenic is naturally occurring toxic metalloid and drinking As2 O3 containing water are recognized to be related to increased risk of neurotoxicity, liver injury, blackfoot disease, hypertension, and cancer. On the contrary, As2 O3 has been an ancient drug used in traditional Chinese medicine with substantial anticancer activities, especially in the treatment of acute promyelocytic leukemia as well as chronic wound healing. However, the cytotoxicity and detail mechanisms of As2 O3 action in solid cancer cells, such as oral cancer cells, are largely unknown. In this study, we have primarily cultured four pairs of tumor and nontumor cells from the oral cancer patients and treated the cells with As2 O3 alone or combined with dithiothreitol (DTT). The results showed that 0.5 µM As2 O3 plus 20 µM DTT caused a significant cell death of oral cancer cells but not the nontumor cells. Also As2 O3 plus DTT upregulated Bax and Bak, downregulated Bcl-2 and p53, caused a loss of mitochondria membrane potential in oral cancer cells. On the other way, As2 O3 also triggered endoplasmic reticulum stress and increased the levels of glucose-regulated protein 78, calpain 1 and 2. Our results suggest that DTT could synergistically enhance the effects of As2 O3 on killing oral cancer cells while nontoxic to the nontumor cells. The combination is promising for clinical practice in oral cancer therapy and worth further investigations. © 2015 Wiley Periodicals, Inc. Environ Toxicol 32: 17-27, 2017.

Baicalin Scavenged Reactive Oxygen Species and Protected Human Keratinocytes Against UVB-induced Cytotoxicity.

Ultraviolet B (UVB), with a wavelength of 280-320 nm, represents one of the most important environmental factors for skin disorders, including sunburn, hyperpigmentation, solar keratosis, solar elastosis and skin cancer. Therefore, protection against excessive UVA-induced damage is useful for prevention of sunburn and other human diseases. Baicalin, a major component of traditional Chinese medicine Scutellaria baicalensis, has been reported to possess antioxidant and cytostatic capacities. In this study, we examined whether baicalin is also capable of protecting human keratinocytes from UVB irradiation. The results showed that baicalin effectively scavenged reactive oxygen species (ROS) elevated within 4 h after UVB radiation and reversed the UVB-suppressed cell viability and UVB-induced apoptosis after 24 h. Our results demonstrated the utility of baicalin to complement the contributions of traditional Chinese medicine in UVB-induced damage to skin and suggested their potential application as pharmaceutical agents in long-term sun-shining injury prevention.

Andrographolide inhibits adipogenesis of 3T3-L1 cells by suppressing C/EBPß expression and activation.

Andrographolide, a diterpenoid, is the most abundant terpenoid in Andrographis paniculata, a popular Chinese herbal medicine. Andrographolide displays diverse biological activities including hypoglycemia, hypolipidemia, anti-inflammation, and anti-tumorigenesis. Recent evidence indicates that andrographolide displays anti-obesity property by inhibiting lipogenic gene expression, however, the underlying mechanisms remain to be elucidated. In this study, the effects of andrographolide on transcription factor cascade and mitotic clonal expansion in 3T3-L1 preadipocyte differentiation into adipocyte were determined. Andrographolide dose-dependently (0-15µM) inhibited CCAAT/enhancer-binding protein α (C/EBPα) and C/EBPß mRNA and protein expression as well as peroxisome proliferator-activated receptor γ (PPARγ) protein level during the adipogenesis of 3T3-L1 cells. Concomitantly, fatty acid synthase and stearoyl-CoA desaturase expression and lipid accumulation were attenuated by andrographolide. Oil-red O staining further showed that the first 48h after the initiation of differentiation was critical for andrographolide inhibition of adipocyte formation. Andrographolide inhibited the phosphorylation of PKA and the activation of cAMP response element-binding protein (CREB) in response to a differentiation cocktail, which led to attenuated C/EBPß expression. In addition, ERK and GSK3ß-dependent C/EBPß phosphorylation was attenuated by andrographolide. Moreover, andrographolide suppressed cyclin A, cyclin E, and CDK2 expression and impaired the progression of mitotic clonal expansion (MCE) by arresting the cell cycle at the Go/G1 phase. Taken together, these results indicate that andrographolide has a potent anti-obesity action by inhibiting PKA-CREB-mediated C/EBPß expression as well as C/EBPß transcriptional activity, which halts MCE progression and attenuates C/EBPα and PPARγ expression.

Inhibitory Effects of AVEMAR on Proliferation and Metastasis of Oral Cancer Cells.

Oral cancer is keeping its 4th rank on the death causing cancers among Taiwan males, and its metastatic and recurrent rates remain high and a life-threatening issue to the citizens. Fermented wheat germ extract (AVEMAR) is used in clinical cancer nutritional therapy in gastrointestinal cancers but not in oral cancer yet. In this study, the potential of AVEMAR to inhibit tumor proliferation and metastasis of oral cancer was first investigated. Antiproliferative activity of AVEMAR was determined in human oral squamous carcinoma SCC-4 cells by MTT methodology. Wound-healing migration, transwell invasion, and Western blotting assays were carried out to examine the in vitro antimetastatic effects and involved signaling molecules for AVEMAR in oral cancer cells. AVEMAR at 0.2-1.6 mg/ml significantly inhibited the cell viability with IC50 values of 1.19 and 0.98 mg/ml for 24-h and 48-h treatment. Furthermore, AVEMAR could induce cell apoptosis and inhibit the migration and invasion of metastatic SCC-4 cells at a similar dose range. Notably, AVEMAR suppressed the expression of matrix metalloproteinase (MMP)-2 and urokinase plasminogen activator (u-PA), but not MMP-1 or MMP-9, in SCC-4 cells. These results strongly support the antiproliferation and in vitro antimetastatic capacity of AVEMAR which may extend its contributions from cancer nutrition supplements to preventive agent for oral cancer.

Protective Effects of Pyridoxamine Against UVC-induced Programmed Cell Death in HaCaT Cells.

BACKGROUND: Exposure to ultraviolet (UV) light is closely related to human diseases, such as skin cancer, due to irreversible injuries to the skin cells. The UV-induced DNA damage and programmed cell death are important determinants for skin carcinogenesis. The aim of the present study was to investigate the anti-ultraviolet-C (UVC) effects of pyridoxamine in human keratinocyte HaCaT cells and its mechanisms of action. RESULTS: UVC-induced programmed cell death in HaCaT cells was abrogated by treated the cells immediately after UVC irradiation with 40, 80 and 160 µM of pyridoxamine. Monitoring the UVC-induced-specific reactive oxygen species, we found that 20, 40, 80 and 160 µM of pyridoxamine was also effective in suppressing the induction of reactive oxygen species by UVC. CONCLUSION: Overall, our results provided evidence showing that pyridoxamine was effective in protecting HaCaT cells from UVC-induced programmed cell death and may be a potential anti-UVC agent in life and clinical practice.

18-carbon polyunsaturated fatty acids ameliorate palmitate-induced inflammation and insulin resistance in mouse C2C12 myotubes.

Skeletal muscle is a major site of insulin action. Intramuscular lipid accumulation results in inflammation, which has a strong correlation with skeletal muscle insulin resistance (IR). The aim of this study was to explore the effects of linoleic acid, alpha-linolenic acid, and gamma-linolenic acid (GLA), 18-carbon polyunsaturated fatty acids (PUFAs), on palmitic acid (PA)-induced inflammatory responses and IR in C2C12 myotubes. Our data demonstrated that these three test 18-carbon PUFAs can inhibit PA-induced interleukin-6 and tumor necrosis factor-α messenger RNA (mRNA) expression and IR as evidenced by increases in phosphorylated AKT and the 160-kD AKT substrate, mRNA and plasma membrane protein expression of glucose transporter 4, and glucose uptake. Moreover, the 18-carbon PUFAs blocked the effects of PA on activation of mitogen-activated protein kinases (MAPKs), protein kinase C-θ (PKC-θ), AMP-activated protein kinase (AMPK) and nuclear factor-κB (NF-κB). Of note, supplementation with GLA-rich borage oil decreased proinflammatory cytokine production and hindered the activation of MAPKs, PKC-θ and NF-κB in the skeletal muscles of diabetic mice. The 18-carbon PUFAs did not reverse PA-induced inflammation or IR in C2C12 myotubes transfected with a constitutively active mutant IκB kinase-ß plasmid, which suggests the importance of the inhibition of NF-κB activation by the 18-carbon PUFAs. Moreover, blockade of AMPK activation by short hairpin RNA annulled the inhibitory effects of the 18-carbon PUFAs on PA-induced IR but not inflammation. Our findings suggest that the 18-carbon PUFAs may be useful in the management of PA-induced inflammation and IR in myotubes.

Irisflorentin modifies properties of mouse bone marrow-derived dendritic cells and reduces the allergic contact hypersensitivity responses.

Irisflorentin is an isoflavone component derived from the roots of Belamcanda chinensis (L.) DC. In traditional Chinese medicine, this herb has pharmacological properties to treat inflammatory disorders. Dendritic cells (DCs) are crucial modulators for the development of optimal T-cell immunity and maintenance of tolerance. Aberrant activation of DCs can induce harmful immune responses, and so agents that effectively improve DC properties have great clinical value. We herein investigated the effects of irisflorentin on lipopolysaccharide (LPS)-stimulated maturation of mouse bone marrow-derived DCs in vitro and in the contact hypersensitivity response (CHSR) in vivo. Our results demonstrated that treatment with up to 40 µM irisflorentin does not cause cellular toxicity. Irisflorentin significantly lessened the proinflammatory cytokine production (tumor necrosis factor-α, interleukin-6, and interleukin-12p70) by LPS-stimulated DCs. Irisflorentin also inhibited the expression of LPS-induced major histocompatibility complex class II and costimulatory molecules (CD40 and CD86) on LPS-stimulated DCs. In addition, irisflorentin diminished LPS-stimulated DC-elicited allogeneic T-cell proliferation. Furthermore, irisflorentin significantly interfered with LPS-induced activation of IκB kinase, c-Jun N-terminal kinase, and p38, as well as the nuclear translocation of NF-κB p65. Subsequently, treatment with irisflorentin obviously weakened 2,4-dinitro-1-fluorobenzene-induced delayed-type hypersensitivity. These findings suggest new insights into the role of irisflorentin as an immunotherapeutic adjuvant through its capability to modulate the properties of DCs.

Carnosic acid protects against 6-hydroxydopamine-induced neurotoxicity in in vivo and in vitro model of Parkinson's disease: involvement of antioxidative enzymes induction.

The neuroprotective effects of carnosic acid (CA), a phenolic diterpene isolated from rosemary (Rosmarinus officinalis), have been widely investigated in recent years, however, its protection in in vivo still unclear. In this study, we investigated the behavioral activity and neuroprotective effects of CA in a rat model of Parkinson's disease (PD) induced by 6-hydroxydopamine (6-OHDA). Rats were treated with 20mg/kg body weight of CA for 3 weeks before 6-OHDA exposure. Results indicated that CA improved the locomotor activity and reduced the apomorphine-caused rotation in 6-OHDA-stimulated rats. Significant protection against lipid peroxidation and GSH reduction was observed in the 6-OHDA rats pretreated with CA. Pretreatment with CA increased the protein expression of γ-glutamate-cysteine ligase catalytic subunit, γ-glutamate-cysteine ligase modifier subunit, superoxide dismutase, and glutathione reductase compared with 6-OHDA-stimulated rats and SH-SY5Y cells. Immunoblots showed that the reduction of the Bcl-2/Bax ratio, the induction of caspase 3 cleavage, and the induction of poly(ADP-ribose) polymerase (PARP) cleavage by 6-OHDA was reversed in the presence of SB203580 (a p38 inhibitor) or SP600125 (a JNK inhibitor) in SH-SY5Y cells. Rats treated with CA reversed the 6-OHDA-mediated the activation of c-Jun NH2-terminal kinase and p38, the down-regulation of the Bcl-2/Bax ratio, the up-regulation of cleaved caspase 3/caspase 3 and cleaved PARP/PARP ratio, and the down-regulation of tyrosine hydroxylase protein. However, BAM7, an activator of Bax, attenuated the effect of CA on apoptosis in SH-SY5Y cells. These results suggest that CA protected against 6-OHDA-induced neurotoxicity is attributable to its anti-apoptotic and anti-oxidative action. The present findings may help to clarify the possible mechanisms of rosemary in the neuroprotection of PD.

Induction of Pi form of glutathione S-transferase by carnosic acid is mediated through PI3K/Akt/NF-κB pathway and protects against neurotoxicity.

Carnosic acid (CA), a diterpene found in the rosemary (Rosmarinus officinalis), has been reported to have a neuroprotective effect. Glutathione S-transferase (GST) P (GSTP) is a phase II detoxifying enzyme that provides a neuroprotective effect. The aim of this study was to explore whether the neuroprotective effect of CA is via an upregulation of GSTP expression and the possible signaling pathways involved. SH-SY5Y cells were pretreated with 1 µM CA followed by treatment with 100 µM 6-hydroxydopamine (6-OHDA). Both immunoblotting and enzyme activity results show that CA also induced protein expression and enzyme activity of GSTP. Moreover, CA significantly increased the phosphorylation of phosphatidylinositol 3-kinase (PI3K)/Akt, the nuclear translocation of p65, but not mitogen-activated protein kinases (p < 0.05). Pretreatment with LY294002 (a PI3K/Akt inhibitor) suppressed the CA-induced phosphorylation of IκB kinase (IKK) and IκBα, p65 nuclear translocation, and nuclear factor-kappa B (NF-κB)-DNA binding activity as well as GSTP protein expression. Furthermore, CA attenuated 6-OHDA-induced caspase 3 activation, and cell death was reversed by GSTP siRNA or LY294002 treatment. Additionally, male Wistar rats with lesions induced by 6-OHDA treatment in the right striatum responded to treatment with CA, which significantly reversed the reduction in GSTP protein expression that resulted from lesioning. We suggest that CA prevents 6-OHDA-induced apoptosis through an increase in GSTP expression via activation of the PI3K/Akt/NF-κB pathway. Therefore, CA may be a promising candidate for use in the prevention of Parkinson's disease.

The mechanisms of carnosic acid attenuates tumor necrosis factor-α-mediated inflammation and insulin resistance in 3T3-L1 adipocytes.

SCOPE: Insulin resistance has been linked to a low-grade chronic inflammatory response. Carnosic acid (CA), which is found in rosemary, has been reported to have antioxidant, anti-inflammation, and anti-adipogenic properties. Here, we examined the effects of CA on inflammation and insulin resistance in 3T3-L1 adipocytes treated with tumor necrosis factor-α (TNF-α). METHODS AND RESULTS: CA attenuated the TNF-α-induced mRNA expression of inflammatory genes, including IL-6 and monocyte chemoattractant protein-1. CA also attenuated the TNF-α-mediated activation of extracellular signal-regulated kinase, c-Jun NH2-terminal kinase, and c-Jun; the phosphorylation of inhibitor-κB (IκB) kinase (IKK)α/ß, the phosphorylation and degradation of IκBα, the nuclear translocation of p65, and the DNA-binding activity of NF-κB and AP-1. CA or PP242 (an mTOR inhibitor) suppressed the TNF-α-induced protein expression of mTOR, p70S6K, eIF4E, and IL-6. Moreover, CA attenuated the TNF-α-mediated suppression of peroxisome proliferator-activated receptor γ, adiponectin, and adipocyte protein 2. CA reversed the TNF-α-mediated suppression of insulin-stimulated glucose uptake and the phosphorylation of Tyr(632) insulin receptor substrate-1 (IRS-1), Akt, and FoxO1, but decreased the TNF-α-induced phosphorylation of Ser(307) IRS-1 and total FoxO1. CONCLUSION: CA attenuates TNF-α-mediated inflammation via inhibition of NF-κB and AP-1 pathways and insulin resistance via Akt-dependent FoxO1 signaling in 3T3-L1 adipocytes.

Indigofera suffruticosa Mill extracts up-regulate the expression of the π class of glutathione S-transferase and NAD(P)H: quinone oxidoreductase 1 in rat Clone 9 liver cells.

Because induction of phase II detoxification enzyme is important for chemoprevention, we study the effects of Indigofera suffruticosa Mill, a medicinal herb, on the expression of π class of glutathione S-transferase (GSTP) and NAD(P)H: quinone oxidoreductase 1 (NQO1) in rat Clone 9 liver cells. Both water and ethanolic extracts of I. suffruticosa significantly increased the expression and enzyme activities of GSTP and NQO1. I. suffruticosa extracts up-regulated GSTP promoter activity and the binding affinity of nuclear factor erythroid 2-related factor 2 (Nrf2) with the GSTP enhancer I oligonucleotide. Moreover, I. suffruticosa extracts increased nuclear Nrf2 accumulation as well as ARE transcriptional activity. The level of phospho-ERK was augmented by I. suffruticosa extracts, and the ERK inhibitor PD98059 abolished the I. suffruticosa extract-induced ERK activation and GSTP and NQO-1 expression. Moreover, I. suffruticosa extracts, especially the ethanolic extract increased the glutathione level in mouse liver and red blood cells as well as Clone 9 liver cells. The efficacy of I. suffruticosa extracts in induction of phase II detoxification enzymes and glutathione content implies that I. suffruticosa could be considered as a potential chemopreventive agent.

Osthole Improves Spatial Memory Deficits in Rats via Hippocampal α 1-Adrenergic and D 1 /D 2 Receptors.

The present study evaluated the effect of osthole, an active ingredient isolated from Cnidium monnieri L. Cusson, on spatial memory deficits caused by central neurotoxins using the Morris water maze in rats. The involvement of catecholaminergic receptors on the memory-enhancing effect of osthole in rat hippocampus was further investigated by intrahippocampal injection of catecholaminergic receptor antagonists. Intracisternal injection of osthole (10 µ g/brain) improved the spatial performance and working memory impairments caused by the catecholaminergic neurotoxin 6-hydroxydopamine. No significant differences in swimming speeds were observed among sham, neurotoxin-induced, and osthole-treated groups. Intracisternal osthole injection also attenuated the spatial performance and working memory impairments caused by the α 1 receptor antagonist phenoxybenzamine, the D1 receptor antagonist SCH 23390, and the D2 receptor antagonist sulpiride. Therefore, we demonstrated that the effect of osthole on improving spatial memory deficits may be related to the activation of hippocampal α 1 and D1/D2 receptors.

Carnosic acid prevents 6-hydroxydopamine-induced cell death in SH-SY5Y cells via mediation of glutathione synthesis.

Understanding the neuroprotective effects of the rosemary phenolic diterpene carnosic acid (CA) has attracted increasing attention. We explored the mechanism by which CA modulates the neurotoxic effects of 6-hydroxydopamine (6-OHDA) in SH-SY5Y cells. Cells were pretreated with CA for 12 h followed by treatment with 100 µM 6-OHDA for 12 or 24 h. Cell viability determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolim bromide (MTT) assay indicated that 0.1 to 1 µM CA dose-dependently attenuated the cell death induced by 6-OHDA, whereas the effect of 3-5 µM CA was weaker. CA at 1 µM suppressed the 6-OHDA-induced nuclear condensation, reactive oxygen species generation, and cleavage of caspase 3 and PARP. Immunoblots showed that the phosphorylation of c-Jun NH(2)-terminal kinase (JNK) and p38 by 6-OHDA was reduced in the presence of CA. Incubation of cells with CA resulted in significant increases in the total glutathione (GSH) level and the protein expression of the γ-glutamylcysteine ligase catalytic subunit and modifier subunit. L-Buthionine-sulfoximine, an inhibitor of GSH synthesis, attenuated the effect of CA on cell death and apoptosis. Treatment with CA also led to an increase in nuclear factor erythroid-2 related factor 2 (Nrf2) activation, antioxidant response element (ARE)-luciferase reporter activity, and DNA binding to the ARE. Silencing of Nrf2 expression alleviated the reversal of p38 and JNK1/2 activation by CA. These results suggest that the attenuation of 6-OHDA-induced apoptosis by CA is associated with the Nrf2-driven synthesis of GSH, which in turn down-regulates the JNK and p38 signaling pathways. The CA compound may be a promising candidate for neuroprotection in Parkinson's disease.

Carnosic acid induces the NAD(P)H: quinone oxidoreductase 1 expression in rat clone 9 cells through the p38/nuclear factor erythroid-2 related factor 2 pathway.

The anticarcinogenic effect of rosemary has been partly attributed to the modulation of the activity and expression of phase II detoxification enzymes. Here we compared the effects of phenolic diterpenes from rosemary on the expression of NAD(P)H: quinone oxidoreductase 1 (NQO1) in rat Clone 9 liver cells. Cells were treated with 1-20 µmol/L of carnosic acid (CA) or carnosol (CS) for 24 h. Both CA and CS dose dependently increased NQO1 enzyme activity and protein expression, and the induction potency of CA was stronger than that of CS. The increase in NQO1 enzyme activity in cells treated with 10 µmol/L CA and CS was 4.1- and 1.9-fold, respectively (P < 0.05). RT-PCR showed that CA and CS induced NQO1 mRNA in a dose-dependent manner. Furthermore, CA dose dependently induced transcription of nuclear factor erythroid-2 related factor 2 (Nrf2) and antioxidant response element (ARE)-luciferase reporter activity. Silencing of Nrf2 expression alleviated NQO1 protein expression and ARE-luciferase activity by CA. Moreover, the phosphorylation of p38 was mainly stimulated in the presence of CA. Pretreatment with SB203580 or silencing of p38 expression inhibited Nrf2 activation and NQO1 induction. These results suggest that the increased NQO1 expression by CA is likely related to the p38-Nrf2 pathway and help to clarify the possible molecular mechanism of action of rosemary phenolic compounds in drug metabolism and cancer prevention.

Carnosic acid, a rosemary phenolic compound, induces apoptosis through reactive oxygen species-mediated p38 activation in human neuroblastoma IMR-32 cells.

Carnosic acid (CA), a rosemary phenolic compound, has been shown to display anti-cancer activity. We examined the apoptotic effect of CA in human neuroblastoma IMR-32 cells and elucidated the role of the reactive oxygen species (ROS) and mitogen-activated protein kinase (MAPK) associated with carcinogenesis. The result indicated that CA decreased the cell viability in a dose-dependent manner. Further investigation in IMR-32 cells revealed that cell apoptosis following CA treatment is the mechanism as confirmed by flow cytometry, hoechst 33258, and caspase-3/-9 and poly(ADP-ribose) polymerase (PARP) activation. Immunoblotting suggested a down-regulation of anti-apoptotic Bcl-2 protein in the CA-treated cells. In flow cytometric analysis, CA caused the generation of reactive oxygen species (ROS); however, pretreatment with the antioxidant N-acetylcysteine (NAC) attenuated the CA-induced generation of ROS and apoptosis. This effect was accompanied by increased activation of p38 and by decreased activation of extracellular signal-regulated kinase (ERK) as well as activation of c-Jun NH(2)-terminal kinase (JNK). Moreover, NAC attenuated the CA-induced phosphorylation of p38. Silencing of p38 by siRNA gene knockdown reduced the CA-induced activation of caspase-3. In conclusion, ROS-mediated p38 MAPK activation plays a critical role in CA-induced apoptosis in IMR-32 cells.

Andrographolide down-regulates hypoxia-inducible factor-1α in human non-small cell lung cancer A549 cells.

Andrographolide (Andro), a diterpenoid lactone isolated from a traditional herbal medicine Andrographis paniculata, is known to possess multiple pharmacological activities. In our previous study, Andro had been shown to inhibit non-small cell lung cancer (NSCLC) A549 cell migration and invasion via down-regulation of phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway. Here we demonstrated that Andro inhibited the expression of hypoxia-inducible factor-1α (HIF-1α) in A549 cells. HIF-1α plays an important role in tumor growth, angiogenesis and lymph node metastasis of NSCLC. The Andro-induced decrease of cellular protein level of HIF-1α was correlated with a rapid ubiquitin-dependent degradation of HIF-1α, and was accompanied by increased expressions of hydroxyl-HIF-1α and prolyl hydroxylase (PHD2), and a later decrease of vascular endothelial growth factor (VEGF) upon the treatment of Andro. The Andro-inhibited VEGF expression appeared to be a consequence of HIF-1α inactivation, because its DNA binding activity was suppressed by Andro. Molecular data showed that all these effects of Andro might be mediated via TGFß1/PHD2/HIF-1α pathway, as demonstrated by the transfection of TGFß1 overexpression vector and PHD2 siRNA, and the usage of a pharmacological MG132 inhibitor. Furthermore, we elucidated the involvement of Andro in HIF-1α transduced VEGF expression in A549 cells and other NSCLC cell lines. In conclusion, these results highlighted the potential effects of Andro, which may be developed as a chemotherapeutic or an anti-angiogenesis agent for NSCLC in the future.