Sphingolipid biosynthesis upregulation by TOR complex 2-Ypk1 signaling during yeast adaptive response to acetic acid stress.

Acetic acid-induced inhibition of yeast growth and metabolism limits the productivity of industrial fermentation processes, especially when lignocellulosic hydrolysates are used as feedstock in industrial biotechnology. Tolerance to acetic acid of food spoilage yeasts is also a problem in the preservation of acidic foods and beverages. Thus understanding the molecular mechanisms underlying adaptation and tolerance to acetic acid stress is increasingly important in industrial biotechnology and the food industry. Prior genetic screens for Saccharomyces cerevisiae mutants with increased sensitivity to acetic acid identified loss-of-function mutations in the YPK1 gene, which encodes a protein kinase activated by the target of rapamycin (TOR) complex 2 (TORC2). We show in the present study by several independent criteria that TORC2-Ypk1 signaling is stimulated in response to acetic acid stress. Moreover, we demonstrate that TORC2-mediated Ypk1 phosphorylation and activation is necessary for acetic acid tolerance, and occurs independently of Hrk1, a protein kinase previously implicated in the cellular response to acetic acid. In addition, we show that TORC2-Ypk1-mediated activation of l-serine:palmitoyl-CoA acyltransferase, the enzyme complex that catalyzes the first committed step of sphingolipid biosynthesis, is required for acetic acid tolerance. Furthermore, analysis of the sphingolipid pathway using inhibitors and mutants indicates that it is production of certain complex sphingolipids that contributes to conferring acetic acid tolerance. Consistent with that conclusion, promoting sphingolipid synthesis by adding exogenous long-chain base precursor phytosphingosine to the growth medium enhanced acetic acid tolerance. Thus appropriate modulation of the TORC2-Ypk1-sphingolipid axis in industrial yeast strains may have utility in improving fermentations of acetic acid-containing feedstocks.

Spinster 2, a sphingosine-1-phosphate transporter, plays a critical role in inflammatory and autoimmune diseases.

Sphingosine 1-phosphate (S1P) is a pleiotropic bioactive sphingolipid metabolite that regulates numerous processes important for immune responses. S1P is made within cells and must be transported out of cells to exert its effects through activation of 5 specific cell surface GPCRs in an autocrine or paracrine fashion. Spinster 2 (Spns2) transports S1P out of cells, and its deletion in mice reduces circulating levels of S1P, alters immune cell trafficking, and induces lymphopenia. Here we examined the effects of Spns2 deletion on adaptive immune responses and in autoimmune disease models. Airway inflammation and hypersensitivity as well as delayed-type contact hypersensitivity were attenuated in Spns2(-/-) mice. Similarly, Spns2 deletion reduced dextran sodium sulfate- and oxazolone-induced colitis. Intriguingly, Spns2(-/-) mice were protected from the development of experimental autoimmune encephalopathy, a model of the autoimmune disease multiple sclerosis. Deletion of Spns2 also strongly alleviated disease development in collagen-induced arthritis. These results point to a broad role for Spns2-mediated S1P transport in the initiation and development of adaptive immune related disorders.

Spns2, a transporter of phosphorylated sphingoid bases, regulates their blood and lymph levels, and the lymphatic network.

Sphingosine-1-phosphate (S1P), a ligand for 5 specific receptors, is a potent lipid mediator that plays important roles in lymphocyte trafficking and immune responses. S1P is produced inside cells and therefore must be secreted to exert its effects through these receptors. Spinster 2 (Spns2) is one of the cell surface transporters thought to secrete S1P. We have shown that Spns2 can export endogenous S1P from cells and also dihydro-S1P, which is active at all cell surface S1P receptors. Moreover, Spns2 mice have decreased levels of both of these phosphorylated sphingoid bases in blood, accompanied by increases in very long chain ceramide species, and have defective lymphocyte trafficking. Surprisingly, levels of S1P and dihydro-S1P were increased in lymph from Spns2 mice as well as in specific tissues, including lymph nodes, and interstitial fluid. Moreover, lymph nodes from Spns2 mice have aberrant lymphatic sinus that appeared collapsed, with reduced numbers of lymphocytes. Our data suggest that Spns2 is an S1P transporter in vivo that plays a role in regulation not only of blood S1P but also lymph node and lymph S1P levels and consequently influences lymphocyte trafficking and lymphatic vessel network organization.

Margin status, adjuvant treatment and recurrence in buccal cancer.

OBJECTIVE: To assess the prognostic importance of margin in resected buccal cancer within a framework of risk factor-driven postoperative adjuvant treatment. MATERIALS AND METHODS: Consecutive, treatment naïve patients undergoing primary surgical treatment for buccal cancer. Margin was defined as clear (≥5 mm), close (1-4 mm) and involved (<1 mm). Main outcome was association of margin with local recurrence free survival (LRFS). Subgroup analysis of close margin was performed according to receipt or no receipt of adjuvant treatment. A numerical margin cut-off in mm that could independently predict LRFS was sought to be identified. RESULTS: Of the 167 patients included, the frequency of clear, close and involved margins was 50 (30 %), 78 (47 %) and 39 (23 %) respectively, among whom 52 %, 44 % and 98 % received postoperative adjuvant treatment respectively. Clear and close margins had similar 3-year LRFS (89 % and 96 % respectively), while involved margin had worse 3-year LRFS at 65 %. Involved margin was confirmed to be strongly and independently associated with worse LRFS. Within close margin, receipt and no receipt of adjuvant treatment had similar 3-year LRFS (92 % and 100 % respectively). A margin cut-off of 2 mm was identified at or above which LRFS approximated that of clear margin. CONCLUSIONS: This single center cohort study of patients with resected buccal cancer suggests that close margin is distinct from and has a better LRFS than involved margin. A subset of close margin, with margin size ≥ 2 mm and no other adverse features, might be spared adjuvant treatment without compromising outcomes.

Photoaffinity labeling of the sigma-1 receptor with N-[3-(4-nitrophenyl)propyl]-N-dodecylamine: evidence of receptor dimers.

The sigma-1 receptor is a ligand-regulated endoplasmic reticulum (ER) resident chaperone involved in the maintenance of cellular homeostasis. Coupling of the sigma-1 receptor with various ER and/or plasma membrane ion channels is associated with its ability to regulate the locomotor activity and cellular proliferation produced in response to sigma-1 receptor ligands. A number of endogenous small molecules bind to the sigma-1 receptor and have been shown to regulate its activity; these include progesterone, N,N-dimethyltryptamine, d-erythro-sphingosine, and/or other endogenous lipids. We previously reported the synthesis of long chain N-alkylamine derivatives and the characterization of the structure-activity relationship between the chain length of N-alkylamine and affinities at the sigma-1 receptor. Here, we present data demonstrating the photoincorporation of one of these N-alkylamine derivatives, N-[3-(4-nitrophenyl)propyl]-N-dodecylamine (4-NPPC12), to the sigma-1 receptor. Matrix-assisted laser desorption ionization time-of-flight and tandem mass spectrometry showed that 4-NPPC12 photoinserted at histidine 154 of the derivatized population of the sigma-1 receptor. Interestingly, light-dependent photoinsertion of 4-NPPC12 resulted in an enhanced electrophoretic mobility of only 50% of the derivatized receptor molecules as assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The proposed binding and reactivity of 4-NPPC12 evoke a ligand binding model for the sigma-1 receptor that likely involves a receptor dimer and/or oligomer.

Bevacizumab and breast cancer: what does the future hold?

Breast cancer is a major health concern for many women, but despite the current standard therapies, many women still die of metastatic disease. Angiogenesis has been evaluated as a possible target for therapy and bevacizumab (Avastin(®), Genentech/Roche, CA, USA), a monoclonal antibody against VEGF-A, has been developed to target this. Current clinical trials utilizing bevacizumab have shown an increase in progression-free survival, but this has not translated to an increase in overall survival in breast cancer patients. In this article, we summarize the currently published trials utilizing bevacizumab in the treatment of breast cancer and describe various methods of measuring angiogenesis in vitro and in vivo. We also describe the related process of lymphangiogenesis, as this may contribute to the mechanism of cancer progression and may be a potential target for therapy in the future. Understanding these processes may help us develop new treatments for breast cancer.

Characterization of interactions of 4-nitrophenylpropyl-N-alkylamine with ς receptors.

Sigma receptors are small membrane proteins implicated in a number of pathophysiological conditions, including drug addiction, psychosis, and cancer; thus, small molecule inhibitors of sigma receptors have been proposed as potential pharmacotherapeutics for these diseases. We previously discovered that endogenous monochain N-alkyl sphingolipids, including d-erythro-sphingosine, sphinganine, and N,N-dimethylsphingosine, bind to the sigma-1 receptor at physiologically relevant concentrations [Ramachandran, S., et al. (2009) Eur. J. Pharmacol. 609, 19-26]. Here, we investigated several N-alkylamines of varying chain lengths as sigma receptor ligands. Although the K(I) values for N-alkylamines were found to be in the micromolar range, when N-3-phenylpropyl and N-3-(4-nitrophenyl)propyl derivatives of butylamine (1a and 1b, respectively), heptylamine (2a and 2b, respectively), dodecylamine (3a and 3b, respectively), and octadecylamine (4a and 4b, respectively) were evaluated as sigma receptor ligands, we found that these compounds exhibited nanomolar affinities with both sigma-1 and sigma-2 receptors. A screen of high-affinity ligands 2a, 2b, 3a, and 3b against a variety of other receptors and/or transporters confirmed these four compounds to be highly selective mixed sigma-1 and sigma-2 ligands. Additionally, in HEK-293 cells reconstituted with K(v)1.4 potassium channel and the sigma-1 receptor, these derivatives were able to inhibit the outward current from the channel, consistent with sigma receptor modulation. Finally, cytotoxicity assays showed that 2a, 2b, 3a, and 3b were highly potent against a number of cancer cell lines, demonstrating their potential utility as mixed sigma-1 and sigma-2 receptor anticancer agents.

Estradiol induces export of sphingosine 1-phosphate from breast cancer cells via ABCC1 and ABCG2.

Sphingosine 1-phosphate (S1P), a potent sphingolipid mediator produced by sphingosine kinase isoenzymes (SphK1 and SphK2), regulates diverse cellular processes important for breast cancer progression acting in an autocrine and/or paracrine manner. Here we show that SphK1, but not SphK2, increased S1P export from MCF-7 cells. Whereas for both estradiol (E(2)) and epidermal growth factor-activated SphK1 and production of S1P, only E(2) stimulated rapid release of S1P and dihydro-S1P from MCF-7 cells. E(2)-induced S1P and dihydro-S1P export required estrogen receptor-alpha, not GPR30, and was suppressed either by pharmacological inhibitors or gene silencing of ABCC1 (multidrug resistant protein 1) or ABCG2 (breast cancer resistance protein). Inhibiting these transporters also blocked E(2)-induced activation of ERK1/2, indicating that E(2) activates ERK via downstream signaling of S1P. Taken together, our findings suggest that E(2)-induced export of S1P mediated by ABCC1 and ABCG2 transporters and consequent activation of S1P receptors may contribute to nongenomic signaling of E(2) important for breast cancer pathophysiology.

Anti-hyperlipidemic and antioxidant potential of different fractions of Terminalia arjuna Roxb. bark against PX- 407 induced hyperlipidemia.

The three fractions diethyl ether, ethyl acetate and ethanol. of T. arjuna exerted hypolipidemic and antioxidative effects at two different doses levels of 175 and 350 mg/kg body weight in Poloxamer (PX)-407 induced hyperlipidemic albino Wistar rats. The hypolipidemic and antioxidant effects of T. arjuna fractions were noticed as EtOH > diethyl ether > ethyl acetate. The results suggest that ethanolic fraction of T. arjuna possesses the potent properties of being antioxidant and hypolipidemic than other fractions. In turn, it has therapeutic potential for the prevention of coronary arterial disease.

Comparative evaluation of hypoglycemic and hypolipidemic activity of various extract of Anogeissus latifolia bark in streptozotocin-induced diabetic rats.

Background Anogeissus latifolia Wall. (A. latifolia) bark has been traditionally used in the treatment of various diseases which includes diabetes and general debility. The present study was aimed to investigate the comparative hypoglycemic and hypolipidemic activity of various extracts of A. latifolia bark in streptozotocin-induced type 1 diabetic rats. Methods Acute toxicity was carried out at 2 g/kg dose of petroleum ether extract of A. latifolia bark (PEALB), chloroform extract of A. latifolia bark (CEALB) and methanol extract of A. latifolia bark (MEALB) in rats. Diabetes was induced by streptozotocin (STZ, 60 mg/kg, i.p.) and it was confirmed at 72 h. Diabetic rats received above extracts at 100 and 200 mg/kg doses for 28 days. Body weight and blood glucose level were determined at every week after the treatment schedule. Serum biochemical parameters and lipid profile levels were estimated at the end of the study. Results PEALB, CEALB and MEALB were non-toxic and no death was observed at 2 g/kg dose. Administration of MEALB at 100 and 200 mg/kg showed significant (p< 0.01, p< 0.05) improvement in body weight and reduction in blood glucose at third and fourth week of treatment. Altered serum biochemical parameters and lipid profiles level were brought to near normal level significantly (p<0.001) compared to diabetic control rats after the administration of both doses of MEALB. However, PEALB and CEALB did not exhibit significant hypoglycemic and hypolipidemic activity. Conclusions Our findings revealed that long-term (28 days) treatment of MEALB possesses significant hypoglycemic and hypolipidemic activity compared to PEALB and CEALB in type 1 diabetic rats and given evidence to the traditional use of A. latifolia bark in diabetes.

Protein kinase Gin4 negatively regulates flippase function and controls plasma membrane asymmetry.

Plasma membrane function requires distinct leaflet lipid compositions. Two of the P-type ATPases (flippases) in yeast, Dnf1 and Dnf2, translocate aminoglycerophospholipids from the outer to the inner leaflet, stimulated via phosphorylation by cortically localized protein kinase Fpk1. By monitoring Fpk1 activity in vivo, we found that Fpk1 was hyperactive in cells lacking Gin4, a protein kinase previously implicated in septin collar assembly. Gin4 colocalized with Fpk1 at the cortical site of future bud emergence and phosphorylated Fpk1 at multiple sites, which we mapped. As judged by biochemical and phenotypic criteria, a mutant (Fpk1(11A)), in which 11 sites were mutated to Ala, was hyperactive, causing increased inward transport of phosphatidylethanolamine. Thus, Gin4 is a negative regulator of Fpk1 and therefore an indirect negative regulator of flippase function. Moreover, we found that decreasing flippase function rescued the growth deficiency of four different cytokinesis mutants, which suggests that the primary function of Gin4 is highly localized control of membrane lipid asymmetry and is necessary for optimal cytokinesis.

Blood glucose-lowering effect of Tectona grandis flowers in type 2 diabetic rats: a study on identification of active constituents and mechanisms for antidiabetic action.

BACKGROUND: Ayurveda documents antidiabetic activity of Tectona grandis flowers. However, until now, the effects of T. grandis flowers in preclinical models of type 2 diabetes (T2D) have been unknown. Hence, the aim of the present study was to evaluate the blood glucose-lowering effect of methanol extract of T. grandis flowers (METGF) in T2D rats and to identify possible active constituents as well as the mechanisms for the antidiabetic action. METHODS: Rats were rendered diabetic by administration of streptozotocin-nicotinamide (65 mg/kg-110 mg/kg, i.p.). After the induction of diabetes, Groups 3 and 4 received METGF (100 and 200 mg/kg respectively) while Group 5 received glibenclamide (5 mg/kg) orally for 4 weeks. Blood glucose and body weight were determined at the end of Weeks 2 and 4. Hemoglobin, HbA1c, total protein, urea, creatinine, insulin, and lipid levels were determined in Week 4. Active constituents in METGF were identified using HPLC analysis. Antidiabetic mechanisms of METGF were evaluated by investigating the insulin sensitizing action and inhibition of α-amylase and α-glucosidase activity. RESULTS: Both METGF and glibenclamide significantly improved body weight, reduced blood glucose, and normalized altered biochemical parameters (P < 0.001) in T2D rats. The presence of polyphenolic active constituents, such as gallic acid, quercetin, rutin, ellagic acid, ferulic acid, and kaempferol, in METGF was confirmed by HPLC. In vitro, METGF, gallic acid, quercetin, and rutin exhibited significant (P < 0.001) insulin sensitizing action and inhibition of α-amylase and α-glucosidase activity. CONCLUSIONS: Polyphenolic active constituents present in METGF are possibly responsible for the blood glucose-lowering effect in T2D rats via an insulin-sensitizing action, as well as inhibition of α-amylase and α-glucosidase activity.

TORC2-dependent protein kinase Ypk1 phosphorylates ceramide synthase to stimulate synthesis of complex sphingolipids.

Plasma membrane lipid composition must be maintained during growth and under environmental insult. In yeast, signaling mediated by TOR Complex 2 (TORC2)-dependent protein kinase Ypk1 controls lipid abundance and distribution in response to membrane stress. Ypk1, among other actions, alleviates negative regulation of L-serine:palmitoyl-CoA acyltransferase, upregulating production of long-chain base precursors to sphingolipids. To explore other roles for TORC2-Ypk1 signaling in membrane homeostasis, we devised a three-tiered genome-wide screen to identify additional Ypk1 substrates, which pinpointed both catalytic subunits of the ceramide synthase complex. Ypk1-dependent phosphorylation of both proteins increased upon either sphingolipid depletion or heat shock and was important for cell survival. Sphingolipidomics, other biochemical measurements and genetic analysis demonstrated that these modifications of ceramide synthase increased its specific activity and stimulated channeling of long-chain base precursors into sphingolipid end-products. Control at this branch point also prevents accumulation of intermediates that could compromise cell growth by stimulating autophagy.

In Vivo and In Vitro Antidiabetic Activity of Terminalia paniculata Bark: An Evaluation of Possible Phytoconstituents and Mechanisms for Blood Glucose Control in Diabetes.

The present study was aimed to investigate in vivo, in vitro antidiabetic activity of aqueous extract of Terminalia paniculata bark (AETPB) and characterize its possible phytoconstituents responsible for the actions. Type 2 diabetes was induced in rats by streptozotocin-nicotinamide (65 mg/kg-110 mg/kg; i.p.) administration. Oral treatment of AETPB using rat oral needle at 100 and 200 mg/kg doses significantly (P < 0.001) decreased blood glucose and glycosylated haemoglobin levels in diabetic rats than diabetic control rats. AETPB-treated diabetic rats body weight, total protein, insulin, and haemoglobin levels were increased significantly (P < 0.001) than diabetic control rats. A significant (P < 0.001) reduction of total cholesterol and triglycerides and increase in high-density lipoprotein levels were observed in type 2 diabetic rats after AETPB administration. Presence of biomarkers gallic acid, ellagic acid, catechin, and epicatechin in AETPB was confirmed in HPLC analysis. AETPB and gallic acid showed significant (P < 0.001) enhancement of glucose uptake action in presence of insulin in muscle cells than vehicle control. Also AETPB inhibited pancreatic α -amylase and α -glucosidase enzymes. In conclusion, the above actions might be responsible for the antidiabetic activity of AETPB due to presence of gallic acid and other biomarkers.

Resection of the primary tumor improves survival in metastatic breast cancer by reducing overall tumor burden.

BACKGROUND: Although many retrospective studies suggest that resection of the primary tumor improves survival in metastatic breast cancer, animal studies suggest that resection induces metastasis. Moreover, there has been no critical evaluation of how well animal studies actually model metastatic breast cancer. We used our newly established orthotopic cancer implantation under direct vision model to evaluate the hypothesis that primary tumor resection improves survival in metastatic breast cancer by reducing overall tumor burden and improving immune responsiveness. METHODS: Murine mammary adenocarcinoma 4T1-luc2 cells that can be visualized by bioluminescence were implanted orthotopically into BALB/c mice under direct vision. Resection of the primary tumors at days 6, 10, and 28 were compared to sham resection of the contralateral normal mammary gland and observation alone. Tumor burden was quantified by bioluminescence. Tumor-draining lymph nodes were identified by intradermal injection of lymphazurin, and primary tumors, lymph nodes, and lungs were examined pathologically. Kaplan-Meier survival analyses were performed. Splenocyte myeloid-derived suppressor cells (MDSCs) and CD4 or CD8 single positive T lymphocytes were quantified by flow cytometry. RESULTS: Tumors invaded locally, metastasized to regional lymph nodes, and then metastasized to distant organs, with subsequent mortality. Surgical stress increased tumor burden only transiently without affecting survival. When primary tumor resection decreased overall tumor burden substantially, further growth of metastatic lesions did not increase the overall tumor burden compared to observation, and survival was improved, which was not the case when resection did not significantly reduce the overall tumor burden. Decreasing overall tumor burden through resection of the primary tumor resulted in decreased splenic MDSC numbers and increased CD4 and CD8 cells, suggesting the potential for an improved immunologic response to cancer. CONCLUSION: Decreasing overall tumor burden through resection of the primary breast tumor decreased MDSCs, increased CD4 and CD8 cells, and improved survival.

Investigation of hypoglycemic, hypolipidemic and antioxidant activities of aqueous extract of Terminalia paniculata bark in diabetic rats.

OBJECTIVE: To investigate the hypoglycemic, hypolipidemic and antioxidant activities of aqueous extract of Terminalia paniculata bark (AETPB) in streptozotocin (STZ)-induced diabetic rats. METHODS: Acute toxicity was studied in rats after the oral administration of AETPB to determine the dose to assess hypoglycemic activity. In rats, diabetes was induced by injection of STZ (60 mg/kg, i.p.) and diabetes was confirmed 72 h after induction, and then allowed for 14 days to stabilize blood glucose level. In diabetic rats, AETPB was orally given for 28 days and its effect on blood glucose and body weight was determined on a weekly basis. At the end of the experimental day, fasting blood sample was collected to estimate the haemoglobin (Hb), glycosylated haemoglobin (HbA1c), serum creatinine, urea, serum glutamate-pyruvate transaminase (SGPT), serum glutamate-oxaloacetate transaminase (SGOT) and insulin levels. The liver and kidney were collected to determine antioxidants levels in diabetic rats. RESULTS: Oral administration of AETPB did not exhibit toxicity and death at a dose of 2 000 mg/kg. AETPB treated diabetic rats significantly (P<0.001, P<0.01 and P<0.05) reduced elevated blood glucose, HbA1c, creatinine, urea, SGPT and SGOT levels when compared with diabetic control rats. The body weight, Hb, insulin and total protein levels were significantly (P<0.001, P<0.01 and P<0.05) increased in diabetic rats treated with AETPB compared to diabetic control rats. In diabetic rats, AETPB treatment significantly reversed abnormal status of antioxidants and lipid profile levels towards near normal levels compared to diabetic control rats. CONCLUSIONS: Present study results confirm that AETPB possesses significant hypoglycemic, hypolipidemic and antioxidant activities in diabetic condition.

Investigation of in vivo antioxidant property of Abelmoschus esculentus (L) moench. fruit seed and peel powders in streptozotocin-induced diabetic rats.

BACKGROUND: Abelmoschus esculentus (L.) Moench. fruit is a commonly consumed vegetable in many countries due to its rich medicinal value. However, till date, in vivo antioxidant property of A. esculentus has not been scientifically documented in animal models. OBJECTIVE: The present investigation was aimed to evaluate the in vivo antioxidant property of A. esculentus (L.) Moench. peel and seed powder (AEPP and AESP) in streptozotocin (STZ)-induced diabetic rats. MATERIALS AND METHODS: In rats, acute toxicity assessment of AEPP and AESP at 2 g/kg did not show any toxicity. Diabetes was induced by STZ (60 mg/kg, i.p.) injection and diabetic rats received AEPP (100 and 200 mg/kg) as well as AESP (100 and 200 mg/ kg) orally up to 28 days. At the end of the 28 day, diabetic rats were killed and liver, kidney and pancreas were collected to determine superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), reduced glutathione (GSH), and lipid peroxidation level. RESULTS: In diabetic rats, significant (P < 0.001) reduction of liver, kidney and pancreas SOD, CAT, GPx, GSH levels and increase in thiobarbituric acid reactive substances (TBARS) were observed as compared to normal control rats. Administration of both doses of AEPP and AESP significantly (P < 0.001 and P < 0.01) increased liver, kidney and pancreas SOD, CAT, GPx, GSH levels and decreased TBARS (P < 0.001) levels in diabetic rats compared to diabetic control rats. CONCLUSION: Our findings confirmed that A. esculentus peel and seed powder has significant in vivo antioxidant property in diabetic rats.

The ligand binding region of the sigma-1 receptor: studies utilizing photoaffinity probes, sphingosine and N-alkylamines.

The sigma-1 receptor is a 26 kDa endoplasmic reticulum resident membrane protein that has been shown to have chaperone activity in addition to its promiscuous binding to pharmacological agents. Ligand binding domain(s) of the sigma-1 receptor have been identified using the E. coli expressed and purified receptor protein and novel radioiodinated azido photoaffinity probes followed by proteolytic and chemical cleavage strategies. The outcome of these experiments indicates that the sigma-1 receptor ligand binding regions are formed primarily by juxtaposition of its second and third hydrophobic domains, regions where the protein shares considerable homology with the fungal enzyme, sterol isomerase that is essential for the biosynthesis of ergosterol. Data indicate that these hydrophobic steroid binding domain like (SBDL) regions on the sigma-1 receptor are likely to interact selectively with N-alkyl amines such as the endogenous sphingolipids and with synthetic N-alkylamines and N-aralkylamines derivatives. A proposed model for the sigma-1 receptor is presented.

Sphingosine-1-phosphate produced by sphingosine kinase 1 promotes breast cancer progression by stimulating angiogenesis and lymphangiogenesis.

Sphingosine-1-phosphate (S1P) is a pleiotropic bioactive lipid mediator that promotes breast cancer progression by diverse mechanisms that remain somewhat unclear. Here we report pharmacologic evidence of a critical role for sphingosine kinase 1 (SphK1) in producing S1P and mediating tumor-induced hemangiogenesis and lymphangiogenesis in a murine model of breast cancer metastasis. S1P levels increased both in the tumor and the circulation. In agreement, serum S1P levels were significantly elevated in stage IIIA human breast cancer patients, compared with age/ethnicity-matched healthy volunteers. However, treatment with the specific SphK1 inhibitor SK1-I suppressed S1P levels, reduced metastases to lymph nodes and lungs, and decreased overall tumor burden of our murine model. Both S1P and angiopoietin 2 (Ang2) stimulated hemangiogenesis and lymphangiogenesis in vitro, whereas SK1-I inhibited each process. We quantified both processes in vivo from the same specimen by combining directed in vivo angiogenesis assays with fluorescence-activated cell sorting, thereby confirming the results obtained in vitro. Notably, SK1-I decreased both processes not only at the primary tumor but also in lymph nodes, with peritumoral lymphatic vessel density reduced in SK1-I-treated animals. Taken together, our findings show that SphK1-produced S1P is a crucial mediator of breast cancer-induced hemangiogenesis and lymphangiogenesis. Our results implicate SphK1 along with S1P as therapeutic targets in breast cancer.

Antidiabetic, antihyperlipidemic and antioxidant potential of methanol extract of Tectona grandis flowers in streptozotocin induced diabetic rats.

OBJECTIVE: To investigate antidiabetic, antihyperlipidemic and antioxidant activity of methanol extract of Tectona grandis (T. grandis) flowers (METGF) in streptozotocin (STZ) induced diabetic rats to supports its traditional use. METHODS: Acute toxicity study of METGF was carried out in rat to determine its dose for the antidiabetic study. Oral glucose tolerance test (OGTT) was performed to evaluate METGF effect on elevated blood glucose level. Diabetes was induced in rats by administration of STZ (60 mg/kg, ip.) and it was confirmed 72 h after induction. METGF was orally given to the diabetic rats up to 28 days and blood glucose level were estimated each week. On 28 day of the experiment, diabetic rats were sacrificed after the blood collection for the biochemical parameters analysis and liver, kidney was collected to determine antioxidants levels. RESULTS: In acute toxicity, METGF did not show toxicity and death up to a dose 2 000 mg/kg in rats. Administration of METGF 100 and 200 mg/kg significantly (P<0.001) reduced blood glucose levels in OGTT and STZ-induced diabetic rats. Both doses of METGF treatment significantly (P<0.001, P<0.01 and P<0.05) increased body weight, serum insulin, haemoglobin (Hb) and total protein levels in diabetic rats. Also, MEGTF treatment reduced elevated glycosylated haemoglobin (HbA1c) and other biochemical parameters levels significantly (P<0.001) in diabetic rats. Altered lipid profiles and antioxidants levels were reversed to near normal in diabetic rats treated with METGF. CONCLUSIONS: These results concluded that METGF possesses antidiabetic, antihyperglycemic and antioxidant activity which supports its traditional use.