The Fractionated Toona sinensis Leaf Extract Induces Apoptosis of Human Osteosarcoma Cells and Inhibits Tumor Growth in a Murine Xenograft Model.

BACKGROUND: Osteosarcoma is a malignant bone tumor prevalent in adolescents with poor prognosis. Toona sinensis showed potent antiproliferation effect on lung, melatonin, ovary, colon, and liver cancers. However, the effects of the species on osteosarcoma cells are rarely investigated. RESULTS: In this study, we found fraction 1 of Toona sinensis leaf (TSL-1) resulted in inhibition of cell viability in MG-63, Saos-2, and U2OS osteosarcoma cell lines, while it only caused a moderate suppressive effect on normal osteoblasts. In addition, TSL-1 significantly elevated lactate dehydrogenase leakage and induced apoptosis and necrosis in Saos-2 cells. TSL-1 increased mRNA expression of pro-apoptotic factor Bad. Most important, TSL-1 significantly suppressed Saos-2 xenograft tumor growth in nude mice by increasing caspase-3. The IC-50 of TSL-1 for the 3 tested osteosarcoma cells is around 1/9 of that for lung cancer cells. CONCLUSION: We demonstrated that TSL-1, a fractionated extract from TSL, caused significant cytotoxicity to osteosarcoma cells due to apoptosis. In vivo xenograft study showed that TSL-1 suppressed the growth of osteosarcoma cells at least in part by inducing apoptosis. Our results indicate that TSL-1 has potential to be a promising anti-osteosarcoma adjuvant functional plant extract.

Chemopreventive effect of Toona sinensis leaf extract on 7,12-dimethylbenz[a]anthracene-induced hamster buccal pouch squamous cell carcinogenesis.

OBJECTIVE: Toona sinensis leaf extract (TSL) has been shown to have anti-tumor effects on cancer cell lines. This study aimed to investigate the chemopreventive potential and the underlying mechanism of TSL during 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster buccal pouch (HBP) carcinogenesis. METHODS: One hundred hamsters were divided into control (n=30), carcinogenic (n=20), preventive (n=42), and therapeutic (n=8) groups. The animals in carcinogenic and preventive groups were administered reverse osmosis water (carcinogenic group) or TSL (1g/kg bw) (preventive group) by gavage daily for 4 weeks, and their bilateral pouches were painted with a 0.5% DMBA solution for 4, 9, and 12 weeks. The animals in the therapeutic group were treated with DMBA for 12 weeks prior to TSL administration for 4 weeks. Expression levels of survivin, X chromosome-linked inhibitor of apoptosis (XIAP), proliferating cell nuclear antigen (PCNA), inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2) proteins were analyzed by immunohistochemistry. Apoptotic activity was examined by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) method, cytochrome C, and poly (ADP-ribose) polymerase (PARP). RESULTS: In the preventive group, the results showed significant decreases not only in the incidences of squamous cell carcinoma (SCC) (50%) and epithelial dysplasia (62.5%) but also in the tumor number, tumor volume, tumor burden, and the severity of dysplastic lesions. The down-regulation of survivin, XIAP, PCNA, iNOS, and COX-2 proteins and the increased apoptotic activity indicated anti-proliferative and apoptosis-inducing abilities of TSL on DMBA-induced HBP carcinogenesis. CONCLUSIONS: The results suggested that TSL might be a promising candidate for the prevention of oral cancer.

Toona sinensis leaf extract has antinociceptive effect comparable with non-steroidal anti-inflammatory agents in mouse writhing test.

BACKGROUND: The antinociceptive effect of an aqueous extract from the leaves of Toona sinensis (TS, [A. Juss., M. Roem.]) was studied using the writhing test in mice. METHODS: Different extraction fractions from TS leaf extracts (TSL1 to TSL5) were administered orally 1 h before intraperitoneal injection of acetic acid. RESULTS: After treatment with TSL1, TSL2, TSL3, TSL4, and TSL5 at a dose of 1 g/kg, the respective writhing responses were 39.9% (P < 0.001), 19.9% (P < 0.05), 11.7% (P = 0.052), 8.1% (P = 0.188), and 11.4% (P = 0.057) lower than the control group. Mice treated with TSL1 at 1 g/kg (39.9%, P < 0.001), 0.3 g/kg (38.0%, P < 0.001), 0.1 g/kg (46.9%, P < 0.001), and 0.03 g/kg (31.1%, P < 0.001) had significantly lower writhing responses compared with control mice. A time-course experiment was performed, which involved oral administration of TSL1 (0.1 g/kg) at 0, 0.5, 1, 2, and 6 h before acetic acid intraperitoneal injection. The most effective dose of TSL1 was 0.1 g/kg orally, with the effect beginning 30 min before treatment and persisting until 6 h. CONCLUSIONS: This study showed that TS has anti-visceral pain properties comparable with those of rofecoxib (a cyclooxygenase-2 inhibitor) and diclofenac, which suggests promise for the treatment of intractable visceral pain in humans.

Antiproliferative effect of Toona sinensis leaf extract on non-small-cell lung cancer.

Toona sinensis (TS), which is also known as Cedrela sinensis, belongs to Meliaceae family, the compounds identified from this TS leaves possess a wide range of biologic functions, such as hypoglycemic effects, anti-LDL glycative activity, antioxidant activities, and inhibition of sudden acute respiratory syndrome (SARS) coronavirus replication. However, their effect against cancer cells is not well explored. In this study, to understand the cytotoxic effect and molecular mechanism stimulated by TSL-1 (TS leaf extract fraction) we employed three different non-small-cell lung cancer (NSCLC) cell lines: H441 cells (lung adenocarcinoma), H661 cells (lung large cell carcinoma) and H520 cells (lung squamous cell carcinoma). IC50 value was varied between these three cell lines, the least IC(50) value was observed in TSL-1-treated H661cells. Exposure of NSCLC cells to TSL-1 caused cell-cycle arrest in subG1 phase and caused apoptosis. Moreover, TSL-1 treatment decreased the cell-cycle regulators; cyclin D1 and CDK4 proteins by up regulating p27 expression in a dose-dependent manner. Thus, the TSL-1-induced apoptosis was further confirmed by cell morphology, subG1 peak accumulation, poly(adenosine diphosphate [ADP]-ribose) polymerase (PARP) cleavage, propidium iodide (PI)-Annexin-V double staining, and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assay. The decreased Bcl2 protein level was concurrent with an increased Bax protein level in all 3 cell lines. Additionally, the tumoricidal effect of TSL-1 was measured using a xenograft model, after 5 weeks of TSL-1 treatment by various regimen caused regression of tumor. Taken together both these in vitro and in vivo studies revealed that TSL-1 is a potent inhibitor against NSCLC growth and our provoking result suggest that TSL-1 can be a better nutriceutical as a singlet or along with doublet agents (taxane, vinorelbine, and gemcitabine) for treating NSCLC.

Antiproliferative and antitumorigenic activity of Toona sinensis leaf extracts in lung adenocarcinoma.

Toona sinensis is a traditional Chinese herb, and the extracts of T. sinensis leaf possess a variety of biological functions. This study attempted to test the antiproliferative effect of TSL-1 (a bioactive fraction of T. sinensis) in H441 cells (lung adenocarcinoma). The data showed that the antiproliferative effect of TSL-1 on H441 cells is prominent using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. TSL-1-induced apoptosis was confirmed by cell morphology, sub-G(1) peak accumulation, cleavage of poly(ADP)-ribose polymerase, and propidium iodide-annexin V double staining. Furthermore, decreased Bcl-2 accompanied by increased Bax (in western blotting) was found with TSL-1 treatment of H441 cells. TSL-1 treatment-induced G(1) arrest was concurrent with the down-regulation of protein levels of cyclin D1 and cyclin-dependent kinase 4 in H441 cells. Peroral and intraperitoneal administrations of TSL-1 were performed to evaluate the therapeutic efficacy, and peroral administration of TSL-1 was also used to elucidate the therapeutic efficacy in the H441 cell xenograft model in vivo. The data revealed that TSL-1 treatment inhibited H441 tumor growth in both therapeutic and preventive experiments. Taken together, these results demonstrate that TSL-1 possesses the capability of preventing and alleviating lung cancer proliferation in vitro and in vivo with proven nephrological and hepatic safety and has the potential to be developed as an anti-lung cancer drug.

Toona sinensis extracts induced cell cycle arrest and apoptosis in the human lung large cell carcinoma.

Toona sinensis extracts have been shown to exhibit anti-cancer effects in human ovarian cancer cell lines, human promyelocytic leukemia cells and human lung adenocarcinoma. Its safety has also been confirmed in animal studies. However, its anti-cancer properties in human lung large cell carcinoma have not been studied. Here, we used a powder obtained by freeze-drying the supernatant of centrifuged crude extract from Toona sinensis leaves (TSL-1) to treat the human lung carcinoma cell line H661. Cell viability was evaluated by the 3-(4-,5-dimethylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide assay. Flow cytometry analysis revealed that TSL-1 blocked H661 cell cycle progression. Western blot analysis showed decreased expression of cell cycle proteins that promote cell cycle progression, including cyclin-dependent kinase 4 and cyclin D1, and increased the expression of proteins that inhibit cell cycle progression, including p27. Furthermore, flow cytometry analysis showed that TSL-1 induced H661 cell apoptosis. Western blot analysis showed that TSL-1 reduced the expression of the anti-apoptotic protein B-cell lymphoma 2, and degraded the DNA repair protein, poly(ADP-ribose) polymerase. TSL-1 shows potential as a novel therapeutic agent or for use as an adjuvant for treating human lung large cell carcinoma.

Gallic acid, a major component of Toona sinensis leaf extracts, contains a ROS-mediated anti-cancer activity in human prostate cancer cells.

Prostate cancer, the most frequently diagnosed malignancy in elderly males of the United States, has become a major health issue in Asia. Previous studies have demonstrated that leaf extracts of Toona sinensis Roem. contain cytotoxic activity on several cancer cells including prostate cancer cells. In this study, gallic acid is identified as the major anti-cancer compound in T. sinensis leaf extracts. It is cytotoxic to DU145 prostate cancer cells, through generation of reactive oxygen species (ROS) and mitochondria-mediated apoptosis, which were reversed by antioxidants catalase and N-acetylcysteine. Furthermore, gallic acid is shown to block the growth of DU145 cells at G2/M phases by activating Chk1 and Chk2 and inhibiting Cdc25C and Cdc2 activities. In addition, gallic acid has a synergistic effect with doxorubicin in suppressing the growth of DU145 cells. Taken together, our results suggest that gallic acid has the potential to be developed into an anti-prostate cancer drug and is worthy of further studies.

Retinoid X receptor alpha participation in dexamethasone-induced rat bile acid coenzyme A-amino acid N-acyltransferase expression in septic liver.

UNLABELLED: To test the hypothesis that dexamethasone (Dex) treatment would restore rat hepatic bile acid coenzyme A-amino acid N-acyltransferase (rBAT) expression in septic rats after cecal ligation and puncture by increasing expression of retinoic acid X receptor alpha (RXRalpha), we assessed survival rate and bile and bile salt concentration in the Dex-treated septic group and compared these results with those for a nontreated septic group, a Dex-treated nonseptic group, and a sham group. Dexamethasone treatment (0.01 mg/kg) significantly improved the survival rate and increased the bile and bile salt concentration in the bile ducts of septic rats (P = <0.05). In our assessment of bile salt-related genes, during sepsis, there were decreases in protein and mRNA expression of rBAT and cholesterol 7 alpha-hydroxylase (CYP7A1). Treatment with Dex restored expression of rBAT and RXR[alpha] but not CYP7A1, bile salt export pump, or multidrug resistance associated protein 2 (MRP2). Na+-taurocholate cotransport protein and organic anion transporting polypeptide 1 were unchanged. In addition, treatment with Dex also restored the DNA-binding activity of RXR/farnesoid-X receptor to rBAT promoter containing inverted repeat 1 sequence. In an experiment to confirm our findings, RXR[alpha] siRNA was found to significantly block Dex-induced increases in expression of rBAT in hepatocytes taken from septic rats (P < 0.01). CONCLUSION: Dex restored the expression of rBAT in septic rats by enhancing RXR[alpha], a process that might explain the mechanism underlying Dex's anticholestatic effect.

Toona sinensis Roem tender leaf extract inhibits SARS coronavirus replication.

AIM OF THE STUDY: Severe acute respiratory syndrome (SARS) is a life-threatening disease caused by the SARS coronavirus (SARS-CoV). The development of new antiviral agents for SARS-CoV is an important issue. We tried to find potential resource from Traditional Chinese medicine (TCM) for development of new drugs against SARS-CoV. MATERIALS AND METHODS: Our team recruited the potential TCM formulae (also known as Kampo) from two TCM books, Shang-Han Lun (Discussion of Cold-Induced Disorders) and Wen-Bing Tiau-Bein (Differential Management of Febrile Diseases). Several herbs, which were believed to be beneficial for SARS by experienced TCM doctors were also recruited. In addition, a vegetable polular in Taiwan, China and Malaysia, the tender leaf of Toona sinensis Roem (also known as Cedrela sinensis, belongs to the family Meliacceae) was also recruited under the suggestion of botanic experts. These TCM products and plant extrats were then tested for the effectiveness against SARS-CoV in vitro. RESULTS: Only TSL-1, the extract from tender leaf of Toona sinensis Roem was found to have an evident effect against SARS-CoV with selectivity index 12 approximately 17. CONCLUSION: This paper reports for the first time that extract from a vegetable, the tender leaf of Toona sinensis Roem, can inhibit SARS-CoV in vitro. Thererfore, the tender leaf of Toona sinensis Roem may be an important resource agninst SARS-CoV.

Toona sinensis Roem (Meliaceae) leaf extract alleviates hyperglycemia via altering adipose glucose transporter 4.

In this study we tested the effects of Toona sinensis leaf extracted with water (TSL1) on alloxan-induced (50 mg/kgBwt, i.v.) diabetic Long-Even rats. Diabetic rats given TS leaf with water (TSL1), with 50% alcohol (TSL3) or with H2O extract (TSL5) showed lower levels of plasma glucose. Normal rats given Glibenclamide (GC) had lower levels of plasma glucose, but TSL1 administration showed no significant effect on plasma glucose. By contrast, TSL1 or GC given to alloxan-induced diabetic rats showed a 40% reduction in plasma glucose compared to diabetic rats. Diabetic rats had lower levels of insulin. Interestingly, TSL1 or GC given to diabetic rats showed improvements in plasma insulin levels. Diabetic rats had lower expressions of glucose transporter 4 (GLUT4) mRNA (RT-PCR) and GLUT4 protein (Western blot) in brown and white adipose tissues; in contrast, diabetic rats given TSL1 or GC showed a significant increase in both GLUT4 mRNA and protein levels. Moreover, the expressions of GLUT4 mRNA in red and white muscles were not significantly different among diabetic rats, diabetic rats given TSL1 or GC, and the normal rats. Compared to diabetic rats, diabetic rats given TSL1 or GC had lower levels of GLUT4 protein in white muscle but not in red muscle. Conclusively, T. sinensis Roem (Meliaceae) leaf possesses the hypoglycemia effect underlying an increment of insulin to mediate the adipose glucose transporter 4 mechanism.

Antioxidant activities of Toona Sinensis leaves extracts using different antioxidant models.

The aim of the present study was to investigate the antioxidant activity of aqueous extracts of Toona sinensis (TS; 0-100 microg/mL) and gallic acid (0-50 microg/mL), with the purified natural phenolic components evaluated using different antioxidant models. It was found that the TS extracts and gallic acid possess effective antioxidant activity against various oxidative systems in vitro, including the scavenging of free and superoxide anion radicals, reducing power, and metal chelation. However, antioxidant activity in terms of metal chelation was not observed for the gallic acid. Moreover, TS extracts and gallic acid appear to possess powerful antioxidant properties with respect to oxidative modification of human LDL induced by CuSO4, AAPH or sodium nitroprusside, as assessed by the relative electrophoretic mobility, TBARS formation, and cholesterol degradation of oxidized LDL. Furthermore, AAPH-induced oxidative hemolysis, lipid peroxidation, and decline in superoxide dismutase (SOD) activity in human erythrocytes were prevented by both the TS extracts and the gallic acid. Our findings suggest that T. sinensis may act as a chemopreventative agent, providing antioxidant properties and offering effective protection from atherogenesis.

Toona sinensis Roem (Meliaceae) leaf extract alleviates liver fibrosis via reducing TGFbeta1 and collagen.

Toona sinensis Roem (TS) leaf tea as a health food for the improvement of blood sugar and hypertension has been demonstrated. Thioacetamide (TAA), a hepatotoxin, causes the progression of liver fibrosis. In this study, we tested the effects of TS leaf on TAA-induced liver injury. TAA (200mg/kg Bwt/3 days, i.p.) treated rats were orally administrated with TS leaf extract (1g/kg Bwt/10 days) three times. After 30 days treatment, the morphological data showed that TS leaf extract given to TAA-treated rats had less liver fibrosis. The GOT/GPT, collagen 1 and collagen 3 mRNAs of livers in TAA-treated rats were elevated when compared to normal rats. The improvements of GOT/GPT, collagen 1 and collagen 3 mRNAs were shown in the TS leaf extract given to TAA-treated rats. TS leaf extract given to TAA-treated rats showed higher levels of cytochrome P450 (1A1, 2A and reductase) than those of TAA-treated rats. Compared to the TAA-treated group, TGFbeta1 mRNA (RT-PCR) was decreased with an increase of TGFbetaR1 protein (western blot) in the TS leaf extract given to TAA-treated rats. The decreased tendency of FGFR2 was found in the TS leaf extract given to TAA-treated rats. The result implies that TS leaf possesses beneficial effects on liver injury through increments of detoxification and the metabolic pathway.

Role of retinoid-X receptor-alpha in the suppression of rat bile acid coenzyme A-amino acid N-acyltransferase in liver during sepsis.

Sepsis causes intrahepatic cholestasis and leads to hepatic failure. However, the pathophysiology of hepatic events is unclear. Expression of rat hepatic bile acid coenzyme A-amino acid N-acyltransferase (rBAT), a major enzyme for the conjugation of bile acids, is significantly decreased during sepsis. rBAT transcriptional regulation is mainly by a heterodimer of farnesoid-X receptor (FXR) and retinoid-X receptor-alpha (RXR-alpha) via the inverted repeat 1 sequence. During sepsis, nuclear receptors and translocation of RXR-alpha from cytosol to nucleus decrease. The purpose of this study was to further clarify the mechanisms of RXR-alpha-mediated rBAT regulation during polymicrobial sepsis and with dexamethasone treatment. Polymicrobial sepsis was induced in rats by cecal ligation and puncture (CLP). Liver tissues obtained 3, 6, 9, and 18 h after CLP were studied, and hepatocytes were isolated from rats with sepsis. Post-CLP decreases were observed in mRNA levels of rBAT (6 h), protein levels of rBAT (6 h), RXR-alpha (6 h), and FXR (9 h). DNA binding activity of FXR/RXR significantly decreased at 6 h after CLP. Dexamethasone reversed sepsis-inhibited RXR-alpha expression and the binding activity of FXR/RXR to rBAT DNA as well as rBAT protein expression. The results suggest that suppression of rBAT occurs at the transcriptional level, and the decrease in RXR-alpha by septic insult may play a critical role in rBAT suppression at the early stage of polymicrobial sepsis.

Intracellular redistribution of dihydropyridine receptor in the rat heart during the progression of sepsis.

BACKGROUND: Dihydropyridine receptor (DHPR) regulates the rate and force of cardiac muscle contraction. This study examined the alteration in the intracellular redistribution of DHPR and its association with the development of the two distinct cardiodynamic states in the rat heart during the progression of sepsis. MATERIAL AND METHODS: Sepsis was induced by cecal ligation and puncture (CLP). DHPRs were assayed using [(3)H]PN200-100 binding and photoaffinity labeling with [(3)H]azidopine followed by polyacrylamide gel electrophoresis. RESULTS: [(3)H]PN200-110 binding shows that during the early hyperdynamic phase of sepsis (9 h post-CLP), the Bmax was increased by 27% in sarcolemma while decreased by 24% in light vesicle. During the late hypodynamic phase of sepsis (18 h post-CLP), the Bmax was decreased by 39% in sarcolemma but increased by 59% in light vesicle. The sum of the Bmax for both membrane fractions was increased by 16% during early sepsis while decreased by 17% during late sepsis. Photoaffinity labeling shows that the incorporation of [(3)H]azidopine into 165 kDa peptides during early sepsis was increased by 28% in sarcolemma whereas decreased by 23% in light vesicle. During late sepsis, the incorporation was decreased by 38% in sarcolemma but increased by 46% in light vesicle. The sum of the 165 kDa peptides for both membrane fractions was increased by 13% during early while decreased by 13% during late sepsis. CONCLUSIONS: These data indicate that DHPRs in the rat heart were externalized from light vesicles to sarcolemma during the early hyperdynamic phase whereas they were internalized from surface membranes to intracellular sites during the late hypodynamic phase of sepsis. Furthermore, DHPRs were overexpressed during early sepsis while they were underexpressed during late sepsis. Alterations in the expression and intracellular redistribution of DHPRs may contribute to the development of the biphasic cardiodynamic states during the progression of sepsis.

Toona sinensis extracts induces apoptosis via reactive oxygen species in human premyelocytic leukemia cells.

Toona sinensis (T. sinensis), well known in Taiwan as a traditional Chinese medicine, has been shown to exhibit antioxidant effects. In this study, therefore, the ability of T. sinensis to induce apoptosis was studied in cultured human premyelocytic leukemia HL-60 cells. Treatment of the HL-60 cells with a variety of concentrations of the aqueous extracts of T. sinensis (TS extracts) (10-75 microg/ml) and gallic acid (5-10 microg/ml), the natural phenolic components purified from TS extracts, resulted in dose- and time-dependent sequences of events marked by apoptosis, as shown by loss of cell viability and internucleosomal DNA fragmentation. Furthermore, apoptosis in the HL-60 cells was accompanied by the release of cytochrome c, caspase 3 activation and specific proteolytic cleavage of poly (ADP-ribose) polymerase (PARP). This increase in TS extracts- and gallic acid-induced apoptosis was also associated with a reduction in the levels of Bcl-2, a potent cell-death inhibitor, and an increase in those of the Bax protein, which heterodimerizes with and thereby inhibits Bcl-2. Interestingly, TS extracts- and gallic acid-induced dose-dependent reactive oxygen species (ROS) generation in HL-60 cells. We found that catalase significantly decreased TS extracts- or gallic acid-induced cytotoxicity, DNA fragmentation, and ROS production, however, slight reduction was observed with vitamins C and E. Our results indicate that TS extracts- or gallic acid-induced HL-60 apoptotic cell death could be due to the generation of ROS, especially H(2)O(2). The data suggest that T. sinensis exerts antiproliferative action and growth inhibition on HL-60 cells through apoptosis induction, and, therefore, that it may have anticancer properties valuable for application in food and drug products.

The fractionated Toona sinensis leaf extract induces apoptosis of human ovarian cancer cells and inhibits tumor growth in a murine xenograft model.

OBJECTIVE: Aqueous extract from the leaves of Toona sinensis Roem. has been shown to have an anti-proliferative effect on human lung cancer cells. In this study, we analyzed the anti-cancer activity/effect of different extraction fractions of the extract from T. sinensis leaves on ovarian cancer cells. METHODS: Cell viability was determined by XTT cell proliferation assay and cell survival assay. Apoptotic effect was detected by morphological analysis and immunoblotting. Cell cycle effect was evaluated by flow cytometry analysis and immunoblotting. In vivo therapeutic effect was evaluated by the subcutaneous inoculation of SKOV3 cells in nude mice (Foxnlnu/Foxnlnu) model. RESULTS: TSL2 of T. sinensis was more cytotoxic than other fractions and exhibited selectivity for ovarian cancer cell lines. TSL2 arrested SKOV3 ovarian cancer cells at the G2/M phase and induced cancer cells go through apoptotic pathway. Ex vivo xenograft study of nude mice showed that intraperitoneal injection of TSL2 was able to suppress the proliferation of ovarian cancer cells without significant nephrotoxicity, liver toxicity, or bone marrow suppression.

Role of cAMP-response element-binding protein phosphorylation in hepatic apoptosis under protein kinase C alpha suppression during sepsis.

Previous studies have shown that a decrease in protein kinase C (PKC) alpha levels contributes to hepatic failure and/or apoptosis during sepsis, and suppression of PKCalpha plays a critical role in triggering caspase-dependent apoptosis, which can modulate expression of Bcl-xL. However, the underlying molecular mechanism remains uncertain. In the present study, we examined whether a decrease in the nuclear PKCalpha levels causes hepatic apoptosis via modulation of cAMP-response element-binding protein (CREB) or nuclear factor-kappaB (NFkappaB), the crucial factors regulating the expression of prosurvival Bcl-xL. For polymicrobial sepsis induction, a cecal ligation and puncture model was used; at 9 or 18 h after CLP, experiments were terminated, referring as early or late sepsis, respectively. Additionally, PKCalpha was suppressed by stable transfection of antisense PKCalpha plasmid into a Clone-9 rat hepatic epithelial cell. The results showed that the nuclear PKCalpha was significantly decreased in the liver during sepsis, which was accompanied by decreases in phospho-CREB content, DNA-binding activity of CREB, and Bcl-xL expression. Likewise, the binding activity of NFkappaB increased significantly, which was associated with a decrease in cytosolic inhibitory-kappaBalpha content. The in vitro suppression of PKCalpha also resulted in decreases in the phospho-CREB content and DNA-binding activity, which were accompanied by down-regulation of Bcl-xL and apoptosis, but no significant alteration in NFkappaB-binding activity. The in vivo and in vitro results suggest that the suppression of PKCalpha results in a decreased CREB phosphorylation and subsequent down-regulation of Bcl-xL, which may contribute to the hepatic apoptosis during sepsis.

Gene regulation by NMDA receptor activation in the SDN-POA neurons of male rats during sexual development.

The present study was designed to identify possible signaling pathways, which may play a role in prevention of neuronal apoptosis in the sexually dimorphic nucleus of the preoptic area (SDN-POA) after physiological activation of the N-methyl-D-aspartate (NMDA) receptor. Gene response to the blockage of the NMDA receptor by an antagonist (dizocilpine hydrogen maleate; MK-801) was screened after suppression subtractive hybridization (SSH). The results showed that differential screening after SSH detected the presence of some neurotrophic genes (RNA binding motif protein 3 (RBM3), alpha-tubulin) as well as apoptosis-related genes (Bcl-2, cytochrome oxidase subunit II, cytochrome oxidase subunit III) in the SDN-POA of male rats, which were down-regulated by blocking the NMDA receptor. The RT-PCR products of the aforementioned genes in MK-801-treated males were significantly less than that in untreated males. In particular, the expression of Bcl-2 mRNA, including Bcl-2 protein, in male rats were significantly suppressed by MK-801 treatment. Moreover, the binding activity of nuclear factor kappaB (NFkappaB) was significantly higher in male rats than in females, but significantly diminished by blocking the NMDA receptor with MK-801 in male rats. No significant difference in cAMP response element-binding protein (CREB) binding activity was observed among untreated male, MK-801-treated male, untreated female and MK-801-treated female groups. These results suggest that genes regulated by NMDA receptor activation might participate in neuronal growth and/or anti-apoptosis, and support an important signaling pathway of NFkappaB activation and its target gene, Bcl-2, in preventing neuronal apoptosis in the SDN-POA of male rats during sexual development.

Regulatory mechanism of Toona sinensis on mouse leydig cell steroidogenesis.

Toona sinensis (TS), a kind of arbor, widely distributes nowadays in Asia. The leaves of TS have been used as an effective nutritious food in Chinese society for a long time. It was reported that Toona sinensis can induce apoptosis of cancer cells, reduce plasma glucose in diabetic rats, and improve lipolysis of differentiated 3T3-L1 adipocyte and its uptake of glucose. It has also been shown that TS may increase dynamic activity of human sperm. Thus, we are interested to investigate whether Toona sinensis has any effect on mouse Leydig cell testosterone production, which correlates to sperm activity. Primary mouse Leydig cells were purified to conduct the in vitro experiments. Different concentrations of crude Toona sinensis were added to primary mouse Leydig cells and the testosterone production was determined. The results showed that crude TS significantly inhibited both basal and human chorionic gonadotropin (hCG)-stimulated testosterone productions in dose dependent manner, respectively (P<0.05). Crude TS also reduced the forskolin- and dibutyryl-cAMP (dbcAMP)-stimulated testosterone production (P<0.05), which indicated that crude TS might affect protein kinase A (PKA) signal transduction pathway at the site after the formation of cyclic AMP. Moreover, TS inhibited Leydig cell steroidogenesis by suppressing the activity of steroidogenic enzymes including P450 side chain cleavage enzyme, 3 beta-hydroxysteroid dehydrogenase, 17 alpha-hydroxylase, 20 alpha-hydroxylase and 17 beta-hydroxysteroid dehydrogenase (P<0.05). In summary, these results suggested that TS inhibited steroidogenesis by suppressing the cAMP-PKA signaling pathway and the activities of steroidogenic enzymes in normal mouse Leydig cells.

Perinatal androgenization prevents age-related neuron loss in the sexually dimorphic nucleus of the preoptic area in female rats.

To investigate the effect of perinatal testosterone exposure, which simulates the endogenous testosterone peak, on neuron loss during aging, nuclear morphology was evaluated in male and female rats as well as in female rats treated with testosterone perinatally followed by ovariectomy (TE/Ovx). Additionally, neuronal apoptosis, which occurred primarily at postnatal day 8 (PND8), was identified by in situ TUNEL staining. Neuronal density, nuclear volume, total neuronal number and pyknotic ratio were estimated after HE stain at PND8, middle age and old age. The results showed that age-related decrease in neuronal nuclear volume and total neuron number in the sexually dimorphic nucleus of the preoptic area (SDN-POA) of female rats was significantly diminished by TE/Ovx. The pyknotic ratio in the SDN-POA of female rats at PND8 was significantly higher than that of males, and neuronal death was reversed by testosterone exposure, while no significant difference of pyknotic ratios was observed among male, female and TE/Ovx female rats at both middle and old age. Moreover, the high apoptotic incidence of female rats at PND8 was significantly diminished by testosterone exposure. These results suggest that neuron loss in the SDN-POA during aging may be predominantly determined by perinatal testosterone through modulation of postnatal neuronal apoptosis.