PI3-kinase Protein Research Articles

Photobiomodulation hastens diabetic wound healing via modulation of the PI3K/AKT/FoxO1 pathway in an adipose derived stem cell-fibroblast co-culture

Prolonged inflammation and impaired redox balance are important causes of delayed wound healing. Photobiomodulation (PBM) enhances delayed wound healing by modulating various cellular signaling pathways involved in the wound healing process. This study aimed to reveal the mechanisms of action of PBM in accelerating wound healing in a diabetic adipose derived stem cell (ADSC)-fibroblast co-culture cell model. ADSC-fibroblast co-culture cells were divided into normal (N), normal wounded (NW), diabetic (D) and diabetic wounded (DW) groups and were irradiated (wavelength: 660 or 830 nm; energy density: 5 J/cm2). Unirradiated cells (0 J/cm2) served as controls. Wound closure/migration was recorded in NW and DW groups using light microscopy. Signaling pathway proteins (PI3 kinase, AKT and FoxO1) modulated by PBM were evaluated by immunofluorescence and western blotting. ELISA was used to measure the levels of antioxidants (HMOX1, SOD and CAT). PBM treatment effectively enhanced cell migration and wound closure in irradiated groups. Furthermore, PBM elevated PI3 kinase and AKT signaling proteins that in turn elevated antioxidant levels. These results demonstrate that PBM at 660 and 830 nm increases migration of co-culture cells and is mediated at least in part through the activation/regulation of the PI3K/AKT/FoxO1 signaling pathway. PBM could be a promising therapeutic approach which can be used in chronic wound treatment.

A phase 2 biomarker-driven study of ruxolitinib demonstrates effectiveness of JAK/STAT targeting in T-cell lymphomas

AbstractSignaling through JAK1 and/or JAK2 is common among tumor and nontumor cells within peripheral T-cell lymphoma (PTCL). No oral therapies are approved for PTCL, and better treatments for relapsed/refractory disease are urgently needed. We conducted a phase 2 study of the JAK1/2 inhibitor ruxolitinib for patients with relapsed/refractory PTCL (n = 45) or mycosis fungoides (MF) (n = 7). Patients enrolled onto 1 of 3 biomarker-defined cohorts: (1) activating JAK and/or STAT mutations, (2) ≥30% pSTAT3 expression among tumor cells by immunohistochemistry, or (3) neither or insufficient tissue to assess. Patients received ruxolitinib 20 mg PO twice daily until progression and were assessed for response after cycles 2 and 5 and every 3 cycles thereafter. The primary endpoint was clinical benefit rate (CBR), defined as the combination of complete response, partial response (PR), and stable disease lasting at least 6 months. Only 1 of 7 patients with MF had CBR (ongoing PR > 18 months). CBR among the PTCL cases (n = 45) in cohorts 1, 2, and 3 were 53%, 45%, and 13% (cohorts 1 & 2 vs 3, P = .02), respectively. Eight patients had CBR > 12 months (5 ongoing), including 4 of 5 patients with T-cell large granular lymphocytic leukemia. In an exploratory analysis using multiplex immunofluorescence, expression of phosphorylated S6, a marker of PI3 kinase or mitogen-activated protein kinase activation, in <25% of tumor cells was associated with response to ruxolitinib (P = .05). Our findings indicate that ruxolitinib is active across various PTCL subtypes and support a precision therapy approach to JAK/STAT inhibition in patients with PTCL. This trial was registered at www.clincialtrials.gov as #NCT02974647.

Progression-free survival of prostate cancer patients is prolonged with a higher regucalcin expression in the tumor tissues: Overexpressed regucalcin suppresses the growth and bone activity in human prostate cancer cells

Prostate cancer, which is a bone metastatic cancer, is the second leading cause of cancer-related death in men. There is no effective treatment for metastatic prostate cancer. Regucalcin has been shown to contribute as a suppressor in various types of human cancers. In the present study, furthermore, we investigate an involvement of regucalcin in suppression of prostate cancer. Regucalcin expression was compared in 131 primary tumor tissues and 19 metastatic tumor tissues in prostate cancer patients. Regucalcin expression in the metastatic tumor was found to be reduced as compared with that in primary tumor. The progression-free survival rate was prolonged in patients with a higher regucalcin expression. Translationally, overexpression of regucalcin in bone metastatic human prostate cancer PC-3 and DU-145 cells suppressed colony formation and cell growth in vitro. Mechanistically, overexpressed regucalcin enhanced the levels of p53, Rb, and p21, and decreased the levels of Ras, PI3 kinase, Akt, and mitogen-activated protein kinase, leading to suppression of cell growth. Furthermore, higher regucalcin expression suppressed the levels of nuclear factor-κB p65, β-catenin, and signal transducer and activator of transcription 3, which regulate a transcription activity. Cell growth was promoted by culturing with the calcium agonist Bay K 8644. This effect was blocked by overexpression of regucalcin. Notably, overexpressed regucalcin suppressed bone metastatic activity of PC-3 and DU-145 cells when cocultured with preosteoblastic or preosteoclastic cells. Regucalcin may suppress the development of human prostate cancer, suggesting that gene delivery systems in which its expression is forced may be a novel therapeutic strategy.

Design, synthesis, in-silico and in-vitro evaluation of di-cationic pyridinium ionic liquids as potential anticancer scaffolds

An array of dicationic pyridinium ionic liquids (DILs) based hydrazone linkage were designed and synthesized via the quaternization of the appropriate bispyridine hydrazone with different phenacyl halides and led to the formation of halogenated DILs, which undergo metathesis reaction to give the specific task dicationic pyridinium liquids carrying fluorinated counter anions (PF6−, BF4−, CF3COO−). The newly synthesized DILs were well characterized using whole spectroscopic data. The Anticancer evaluation of DILs against breast and colon cancer cell lines revealed that compound 22 appears to be the most active compound in the series with IC50 in the two-digit micromolar range. The in-vitro anticancer results were further supported by in-silico molecular docking studies revealing the highest potency of compound 22. The docking analysis demonstrated good docking score and binding affinities of the synthesized compounds on the target protein PI3Kinase.

High Glucose-Mediated Tyrosine Nitration of PI3-Kinase: A Molecular Switch of Survival and Apoptosis in Endothelial Cells.

Diabetes and hyperglycemia are associated with increased retinal oxidative and nitrative stress and vascular cell death. Paradoxically, high glucose stimulates expression of survival and angiogenic growth factors. Therefore, we examined the hypothesis that high glucose-mediated tyrosine nitration causes inhibition of the survival protein PI3-kinase, and in particular, its regulatory p85 subunit in retinal endothelial cell (EC) cultures. Retinal EC were cultured in high glucose (HG, 25 mM) for 3 days or peroxynitrite (PN, 100 µM) overnight in the presence or absence of a peroxynitrite decomposition catalyst (FeTPPs, 2.5 µM), or the selective nitration inhibitor epicatechin (100 µM). Apoptosis of ECs was assessed using TUNEL assay and caspase-3 activity. Immunoprecipitation and Western blot were used to assess protein expression and tyrosine nitration of p85 subunit and its interaction with the p110 subunit. HG or PN accelerated apoptosis of retinal ECs compared to normal glucose (NG, 5 mM) controls. HG- or PN-treated cells also showed significant increases in tyrosine nitration on the p85 subunit of PI3-kinase that inhibited its association with the catalytic p110 subunit and impaired PI3-kinase/Akt kinase activity. Decomposing peroxynitrite or blocking tyrosine nitration of p85 restored the activity of PI3-kinase, and prevented apoptosis and activation of p38 MAPK. Inhibiting p38 MAPK or overexpression of the constitutively activated Myr-Akt construct prevented HG- or peroxynitrite-mediated apoptosis. In conclusion, HG impairs pro-survival signals and causes accelerated EC apoptosis, at least in part via tyrosine nitration and inhibition of PI3-kinase. Inhibitors of nitration can be used in adjuvant therapy to delay diabetic retinopathy and microvascular complication.

415 - High Glucose-Mediated Tyrosine Nitration Inhibits Survival Signal in Endothelial Cells

Introduction Evidence of retinal oxidative and nitrative stress has been well-documented in models of diabetic retinopathy. Here, we examined the effects of high glucose and peroxynitrite on tyrosine nitration and inhibition of the survival protein PI3-kinase and in particular p85 subunit in retinal endothelial cells. Methods Retinal endothelial cells were cultured in high glucose (25mM) for 3-days or peroxynitrite (100μM) for 1-day in the presence or absence a peroxynitrite decomposition catalyst (FeTPPs, 2.5μM) or the selective nitration inhibitor epicatechin (100μM). Tyrosine nitration of p85 subunit and its association with the p110 subunit were examined using immunoprecipitation. Endothelial cell apoptosis was examined using TUNEL assays and caspase-3 activity. Results High glucose or exogenous peroxynitrite caused significant increase in apoptosis of retinal endothelial cells compared to controls. Treatment with FeTPPs or epicatechin blocked these effects, implying a causal role of peroxynitrite. High glucose- or peroxynitrite-treated cells also showed significant increases in tyrosine nitration on the p85 subunit of PI 3-kinase that inhibited its association with p110 subunit and inhibition of PI 3-kinase/Akt kinase activity. Inhibiting peroxynitrite formation or blocking tyrosine nitration of p85 restored the activity of PI 3-kinase and Akt kinase and normalized pro-survival function. Conclusions High glucose impairs pro-survival signal and causes accelerated endothelial cell apoptosis via the action of peroxynitrite in causing tyrosine nitration of PI 3-kinase and inhibiting activity of Akt kinase. Inhibitors of nitration can be further developed to combat vascular complication in diabetes.

Palmitic acid suppresses apolipoprotein M gene expression via the pathway of PPARβ/δ in HepG2 cells

It has been demonstrated that apolipoprotein M (APOM) is a vasculoprotective constituent of high density lipoprotein (HDL), which could be related to the anti-atherosclerotic property of HDL. Investigation of regulation of APOM expression is of important for further exploring its pathophysiological function in vivo. Our previous studies indicated that expression of APOM could be regulated by platelet activating factor (PAF), transforming growth factors (TGF), insulin-like growth factor (IGF), leptin, hyperglycemia and etc., in vivo and/or in vitro. In the present study, we demonstrated that palmitic acid could significantly inhibit APOM gene expression in HepG2 cells. Further study indicated neither PI-3 kinase (PI3K) inhibitor LY294002 nor protein kinase C (PKC) inhibitor GFX could abolish palmitic acid induced down-regulation of APOM expression. In contrast, the peroxisome proliferator-activated receptor beta/delta (PPARβ/δ) antagonist GSK3787 could totally reverse the palmitic acid-induced down-regulation of APOM expression, which clearly demonstrates that down-regulation of APOM expression induced by palmitic acid is mediated via the PPARβ/δ pathway.

Natriuretic Peptide Receptor-C Agonist Attenuates the Expression of Cell Cycle Proteins and Proliferation of Vascular Smooth Muscle Cells from Spontaneously Hypertensive Rats: Role of Gi Proteins and MAPkinase/PI3kinase Signaling

Vascular smooth muscle cells (VSMC) from spontaneously hypertensive rats (SHR) exhibit hyperproliferation and overexpression of cell cycle proteins. We earlier showed that small peptide fragments of cytoplasmic domain of natriuretic receptor-C (NPR-C) attenuate vasoactive peptide-induced hyperproliferation of VSMC. The present study investigated if C-ANP4–23, a specific agonist of NPR-C, could attanuate the hyperproliferation of VSMC from SHR by inhibiting the overexpression of cell cycle proteins and examine the underlying signaling pathways contributing to this inhibition. The proliferation of VSMC was determined by [3H] thymidine incorporation and the expression of proteins was determined by Western blotting. The hyperproliferation of VSMC from SHR and overexpression of cyclin D1,cyclin A, cyclin E, cyclin-dependent kinase 2 (cdk2), phosphorylated retinoblastoma protein (pRb), Giα proteins and enhanced phosphorylation of ERK1/2 and AKT exhibited by VSMC from SHR were attenuated by C-ANP4–23 to control levels. In addition, in vivo treatment of SHR with C-ANP4–23 also attenuated the enhanced proliferation of VSMC. Furthemore, PD98059, wortmannin and pertussis toxin, the inhibitors of MAP kinase, PI3kinase and Giα proteins respectively, also attenuated the hyperproliferation of VSMC from SHR and overexpression of cell cycle proteins to control levels. These results indicate that NPR-C activation by C-ANP4–23 attenuates the enhanced levels of cell cycle proteins through the inhibition of enhanced expression of Giα proteins and enhanced activation of MAPkinase/PI3kinase and results in the attenuation of hyperproliferation of VSMC from SHR. It may be suggested that C-ANP4–23 could be used as a therapeutic agent in the treatment of vascular complications associated with hypertension, atherosclerosis and restenosis.

Monoclonal Antibody Against ROR1 in Chronic Lymphocytic Leukemia Cells Induced Apoptosis Via PI3-Kinase/AKT/CREB Pathway

AbstractAbstract 1769 Background:Phosphoinositide 3-kinase (PI3K)/AKT cascade regulates cell survival, proliferation and differentiation in a variety of cells. In CLL cells PI3K pathway is constitutively activated leading to AKT activation and phosphorylation of cAMP response element-binding protein (CREB). CREB is a transcription factor overexpressed and constitutively phosphorylated in a variety of cancers and seems to have a role in tumor pathobiology. There is a great need to develop novel strategies for targeted therapy in CLL. Monoclonal antibodies (mAbs) specifically targeting leukemic cells might be a rewarding approach. ROR1 is a type I transmembrane receptor tyrosine kinase belonging to one of the twenty families of receptor tyrosine kinases (RTKs). ROR1 is overexpressed on CLL cells but not in white blood cells of healthy donors. ROR1 is constitutively phosphorylated in CLL and siRNA transfection induced apoptosis. We have developed a unique anti-ROR1 mAb directed against CRD (cysteine-rich domain) of the extracellular region of ROR1 capable of inducing direct apoptosis of primary CLL cells. Our anti-CRD mAb induced dephosphorylation of the ROR1 molecule. Aims:To study the apoptotic effect of an anti-ROR1 CRD mAb and effects on downstream signaling pathways involved in CLL, specially the PI3-kinase/AKT/CREB pathway using primary CLL cells. Methods:Using a peptide-based mouse mAb generation method we produced several mAbs against the three extracellular domains of ROR1. In the current study we used one of the best anti-ROR1 antibodies, an anti-CRD mAb raised against the CRD region of ROR1 (Daneshmanesh et al., Leukemia. 2012 Jun;26(6):1348-55). Flow cytometry was used for surface staining of ROR1. Primary CLL cells were incubated with the anti-ROR1 CRD mAb and apoptosis was detected by the MTT assay and Annexin V/propidium iodide (flow cytometry) methods in a 24 h assay. Antibody untreated and treated cell lysates were prepared and subjected to Western blot analysis for identification of signaling molecules involved in apoptosis induced by the anti-ROR1 CRD mAb. We analysed total and phosphorylated levels of the following signaling proteins: AKT, p-AKT, PI3K, p-PI3K, CREB, p-CREB, ERK, p-ERK, PKC and p-PKC. Phosphoproteins were measured before incubation with the mAb and after 20 min-2 h. Results:ROR1 surface expression was detected on 80–85% of the CLL cells. The frequency of apoptotic cells induced by the anti-CRD mAb was in the range of 45–50% which is in accordance with our previous reports (see above). Time kinetics experiments using anti-ROR1 CRD mAb incubated with primary CLL cells revealed dephosphorylation of ROR1 downstream signaling molecules. We analysed the following molecules known to be involved in CLL: PKC, PI3-kinase and ERK1/2. After co-culturing CLL cells with the anti-ROR1 CRD mAb, Western blot analysis showed decreased level of phosphorylated AKT in treated compared to untreated samples. No changes in the phosphorylation levels of ERK1/2 and PKC proteins were seen. Furthermore, we analysed the PI3-kinase protein which is upstream of AKT, and noticed that in CLL cells treated with the anti-ROR1 CRD mAb, the phosphorylation intensity of PI3-kinase p85 isoform has decreased but not p55 isoforrn. Moreover, we also studied the CREB phosphorylation in treated and untreated CLL samples and detected dephosphorylation of CREB in treated as compared to untreated samples. Conclusion:Incubation of CLL cells with an anti-ROR1 CRD mAb induced apoptosis of primary CLL cells. Apoptosis was preceded by dephosphorylation within 2 h of PI3-kinase, AKT and CREB proteins indicating deactivation of these signaling proteins by the anti-ROR1 mab. In untreated CLL cells no effect on phosphorylation of these proteins was noted. Furthermore our ROR1 mAb did not dephosphorylate PKC or ERK. Our data may suggest that activation of CREB molecule might occur via the PI3K/AKT pathway and may be a survival signal in CLL cells associated with the aberrant expression of ROR1. The constitutive phosphorylation of PKC and ERK1/2 seen in CLL might not be related to the overexpression of ROR1. Further studies are warranted for a better understanding of signaling pathways associated with ROR1 and the downstream signaling effects of ROR1 targeting drugs. Disclosures:No relevant conflicts of interest to declare.

Puerarin activates endothelial nitric oxide synthase through estrogen receptor-dependent PI3-kinase and calcium-dependent AMP-activated protein kinase

The cardioprotective properties of puerarin, a natural product, have been attributed to the endothelial nitric oxide synthase (eNOS)-mediated production of nitric oxide (NO) in EA.hy926 endothelial cells. However, the mechanism by which puerarin activates eNOS remains unclear. In this study, we sought to identify the intracellular pathways underlying eNOS activation by puerarin. Puerarin induced the activating phosphorylation of eNOS on Ser1177 and the production of NO in EA.hy926 cells. Puerarin-induced eNOS phosphorylation required estrogen receptor (ER)-mediated phosphatidylinositol 3-kinase (PI3K)/Akt signaling and was reversed by AMP-activated protein kinase (AMPK) and calcium/calmodulin-dependent kinase II (CaMKII) inhibition. Importantly, puerarin inhibited the adhesion of tumor necrosis factor (TNF)-α-stimulated monocytes to endothelial cells and suppressed the TNF-α induced expression of intercellular cell adhesion molecule-1. Puerarin also inhibited the TNF-α-induced nuclear factor-κB activation, which was attenuated by pretreatment with N G -nitro- l-arginine methyl ester, a NOS inhibitor. These results indicate that puerarin stimulates eNOS phosphorylation and NO production via activation of an estrogen receptor-mediated PI3K/Akt- and CaMKII/AMPK-dependent pathway. Puerarin may be useful for the treatment or prevention of endothelial dysfunction associated with diabetes and cardiovascular disease.

“Arginine paradox” in cardiomyocytes of Sprague Dawley and spontaneously hypertensive rats: α2-adrenoreceptor-mediated regulation of L-type Ca2+ currents by L-arginine

The “arginine paradox” in cardiomyocytes isolated from the left ventricle of Spraque Dawlay (SD) and spontaneously hypertensive rats (SHR) was studied. With 1 mM L-arginine in the bath, the addition of 5 mM L-arginine to incubation medium increased NO production and inhibited amplitude of L-type Ca2+ currents in SD cardiomyocytes. A variety of compounds, including the antagonist of α2-adrenoceptors yohimbine and inhibitors of PI3 kinase (wortmanine), NO synthase (7NI), and cGMP-dependent protein kinase (KT5823), dramatically weakened the inhibitory effects of 5 mM L-arginine on Ca2+ currents. The agonist of α2-adrenoceptors guanabenz acetate increased NO production and inhibited Ca2+ currents, while wortmanine, 7NI, and KT5823 antagonized guanabenz. In SHR cardiomyocytes, the “arginine paradox” was not observed: 5 mM L-arginine affected neither NO production nor Ca2+ currents. Consistently, guanabenz acetate did not alter NO production and inhibited Ca2+ currents to a much smaller extent in SHR cardiomyocytes as compared to SD cardiomyocytes. Taken together, the data of the inhibitory analysis suggest that millimolar L-arginine serves as an agonist of α2-adrenoceptors, which are coupled to PI3K-Akt pathway as well as downstream NO-cGMP pathway to control activity of L-type Ca2+ channels, thus providing new insights into the “arginine paradox” in cardiomyocytes.

Single Cell Network Profiling as a Platform to Reveal Leukemia-Specific Signaling Signatures and Sensitivity to Kinase Inhibitor Therapies

AbstractAbstract 2753Aberration in kinase activity by either the gain-of-function mutations or overexpression of the encoding genes plays a pivotal role in myeloid leukemogenesis. An increasing number of kinase inhibitors are being developed as “targeted therapies” for the treatment of acute myeloid leukemia (AML) and other myeloproliferative disorders. However, given the biologic and clinical heterogeneity inherent to these diseases, an unmet medical need exists for tools to guide the choice of inhibitor(s) most relevant for individual patients. With the aim of developing a platform for the biological characterization of patient-specific tumors, which could assist patient stratification strategies for clinical trials, we combined signaling pathway analysis and drug response profiling in AML samples using Single Cell Network Profiling (SCNP) assays. This technology allows for the simultaneous measurement of the activation state of multiple signaling proteins at the single cell level. Cryopreserved mononuclear cells from blood leukapheresis of patients with AML (N=6) were analyzed in two experimental arms. #1 Signaling Arm:A panel of kinase inhibitors targeting FLT3, cKit, PI3 kinase, mTor, MEK, and JAK proteins was added at varying concentrations to the AML cells followed by stimulation with G-CSF, IL-27, cKit ligand (SCF), FLT3 ligand (FLT3L), or a vehicle control. Using multiparameter flow cytometry, the phosphoylation status of AKT, ERK, S6 Ribosome, STAT1, STAT3, and STAT5 were measured in multiple leukemia cell subsets defined by expression of CD34, cKit, CD3, and light scatter properties. Per sample, there were a total of 68 treatments measuring 3 phospho-proteins in 3 cell subsets. #2 Apoptosis/Cytostasis Arm:The leukemic cells were driven into cell cycle by exposure to IL-3, SCF, and FLT3L, followed by a 48-hr incubation with a combination of 1 to 5 kinase inhibitors targeting the same pathways referred to previously. The kinase inhibitor impact was measured on distal functional readouts, including apoptosis (cleaved PARP) and cell cycle (CyclinB1-S/G2 phase; p-Histone H3-M phase). These results were compared with results using bone marrow samples from healthy donors (N=6). Results:Each patient's sample generated a unique signaling profile. A broad range of protein-specific phosphorylation status of AKT, ERK, S6 Ribosome, STAT1, STAT3, and STAT5 was observed in response to growth factor stimulation. Response was measured by setting a region gate that captures the overall percentage of cells with fluorescence above the unstimulated level. The percentage of SCF, G-CSF and FLT3L responsive cells ranged between 6%-49%, 3%-56%, and 3%-22%, respectively. Overall, patient samples could be grouped based on their signaling profile, proliferative potential, and sensitivity to kinase inhibitor treatment. Specifically, the 2 samples with the greatest SCF and G-CSF signaling response also showed the most robust in vitro proliferation and were most sensitive to the JAK inhibitor, CP-690,550 (1μM) (as measured by cytostasis readouts). Whereas, 2 other samples that displayed only modest SCF and G-CSF signaling, but robust FLT3L signaling expanded slowly in culture and were particularly sensitive to the cytostatic effects of the PI3K inhibitor, GDC-0941, (1uM) or the Flt3 inhibitor, tandutinib, (1uM). Finally, the last 2 AML samples had weak growth factor signaling and did not proliferate in culture and therefore could not be tested for kinase inhibitor-induced cytostasis. While the successfully tested patient samples showed variable sensitivity (as measured by cytostasis and apoptosis) to different drug combinations, the samples from healthy donors showed considerable similarity in response across all inhibitor combinations. Conclusions:This study provides preliminary proof-of-concept on the utility of SCNP to dissect the pathophysiologic heterogeneity of hematologic tumors and assess their differential response to single and combination therapies. Ultimately, this functional pathway profiling and drug sensitivity assay may be useful to stratify patients to different kinase combination treatments tested in clinical trials. Disclosures:Covey:Nodality Inc.: Employment, Equity Ownership. Gulrajani:Nodality Inc.: Employment, Equity Ownership. Cesano:Nodality Inc.: Employment, Equity Ownership.

Proanthocyanidins from the American Cranberry (Vaccinium macrocarpon) inhibit matrix metalloproteinase‐2 and matrix metalloproteinase‐9 activity in human prostate cancer cells via alterations in multiple cellular signalling pathways

Prostate cancer is one of the most common cancers in the Western world, and it is believed that an individual's diet affects his risk of developing cancer. There has been an interest in examining phytochemicals, the secondary metabolites of plants, in order to determine their potential anti-cancer activities in vitro and in vivo. In this study we document the effects of proanthocyanidins (PACs) from the American Cranberry (Vaccinium macrocarpon) on matrix metalloproteinase (MMP) activity in DU145 human prostate cancer cells. Cranberry PACs decreased cellular viability of DU145 cells at a concentration of 25 µg/ml by 30% after 6 h of treatment. Treatment of DU145 cells with PACs resulted in an inhibition of both MMPs 2 and 9 activity. PACs increased the expression of TIMP-2, a known inhibitor of MMP activity, and decreased the expression of EMMPRIN, an inducer of MMP expression. PACs decreased the expression of PI-3 kinase and AKT proteins, and increased the phosphorylation of both p38 and ERK1/2. Cranberry PACs also decreased the translocation of the NF-κB p65 protein to the nucleus. Cranberry PACs increased c-jun and decreased c-fos protein levels. These results suggest that cranberry PACs decreases MMP activity through the induction and/or inhibition of specific temporal MMP regulators, and by affecting either the phosphorylation status and/or expression of MAP kinase, PI-3 kinase, NF-κB and AP-1 pathway proteins. This study further demonstrates that cranberry PACs are a strong candidate for further research as novel anti-cancer agents.

Ginsenoside Rg3 increases nitric oxide production via increases in phosphorylation and expression of endothelial nitric oxide synthase: Essential roles of estrogen receptor-dependent PI3-kinase and AMP-activated protein kinase

We previously showed that ginsenosides increase nitric oxide (NO) production in vascular endothelium and that ginsenoside Rg3 (Rg3) is the most active one among ginseng saponins. However, the mechanism for Rg3-mediated nitric oxide production is still uncertain. In this study, we determined whether Rg3 affects phosphorylation and expression of endothelial nitric oxide synthase (eNOS) in ECV 304 human endothelial cells. Rg3 increased both the phosphorylation and the expression of eNOS in a concentration-dependent manner and a maximal effect was found at 10μg/ml of Rg3. The enzyme activities of phosphatidylinositol 3-kinase (PI3-kinase), c-Jun N-terminal kinase (JNK), and p38 kinase were enhanced as were estrogen receptor (ER)- and glucocorticoid receptor (GR)-dependent reporter gene transcriptions in Rg3-treated endothelial cells. Rg3-induced eNOS phosphorylation required the ER-mediated PI3-kinase/Akt pathway. Moreover, Rg3 activates AMP-activated protein kinase (AMPK) through up-regulation of CaM kinase II and Rg3-stimulated eNOS phosphorylation was reversed by AMPK inhibition. The present results provide a mechanism for Rg3-stimulated endothelial NO production.

GPR30 Signaling in Neonatal Hamster Ovary Involves PI3 Kinase (PI3K) and ERK-1/2 Pathways.

We have shown that estradiol (E2) stimulates the formation and development of hamster primordial follicles in vivo and in vitro. A part of the E2 action is mediated by GPR30, but the mechanisms are not known. The objective of this study was to investigate whether GPR30 signaling during primordial follicle formation involved PI3 kinase or ERK-1/2 pathway. Wortmannin or U0126 suppressed the stimulatory effect E2-BSA on primordial follicle formation. PI3 kinase protein was detected in the oocytes of 13-day old fetus (E13), but the enzyme appeared in somatic cells on postnatal day 6 (P6). The intensity of PI3K immunosignal increased in the granulosa cells of newly formed primordial follicles on P8 and primary follicles on P9. PI3K expression correlated well with the formation of primordial follicles, with a higher expression on P8, when the first cohort of primordial follicles appear. The levels of phosphoAkt (pAkt) also increased from P7 and reached a peak on P9, suggesting that PI3K action via Akt might be involved in primordial follicle formation. pAkt immunosignal was located mainly in the oocytes and in adjacent somatic cells before the formation of primordial follicles. After follicle formation, pAkt immunosignal shifted to the granulosa cells of primordial and primary follicles. Similarly, higher ERK-1/2 immunosignal was present in the oocytes and adjacent somatic cells, and increased ERK1/2 phosphorylation correlated with the appearance of the first cohort of primordial follicles. Treatment of cultured P6 ovarian cells with 10 nM E2 significantly increased the levels of pAkt and pERK-1/2 within 10 min, while 1 µM E2 had no effect. 10 nM E2 also stimulated the phosphorylation of cRaf and MEK. Whereas Wortmannin blocked E2-induced Akt phosphorylation without affecting ERK-1/2 phosphorylation, U0126 blocked E2-induced ERK1/2 phosphorylation without affecting Akt phosphorylation. Similar phosphorylation patterns were observed when cells were exposed to G1, a GPR30 specific ligand. siRNA knockdown of GPR30 significantly reduced E2- or G1-induced Akt and ERK1/2 phosphorylation, thus providing additional evidence for a GPR30-mediated action. These results together with our previous findings suggest that the mechanisms of E2-regulated primordial follicle formation may involve two parallel signaling modalities, and GPR30 mediates a part of the E2 action during primordial follicle formation. (platform)

Analysis of Binding Properties of Phosphoinositide 3-kinase Through In silico Molecular Docking

Phosphoinositide 3-kinases (PI3-kinases) are increasingly considered to have a key role in intracellular signal transduction in health and disease. Particularly the enzymes plays vital role in wide range of cancer such as breast, ovarian, myeloid leukemia, prostate, Small Cell Lung cancer (SCLC) etc., Compounds such as Wortmannin, LYS2002 are the inhibitors of PI3-kinases but these compounds shown adverse side effects . Hence five natural flavanoids having inhibitory effects on PI3-kinase namely Andrographolide, Kaempferol, Luteolin, Quercetin and Gingerol were taken for in silico prediction of binding affinities of the protein PI3- kinase. Our reports can be used to develop new inhibitors with better binding affinities towards the protein PI3-kinase protein. For the binding analysis the catalytic subunit of the protein PI-3 Kinase p110? was taken for the study as it considered being a potential target in cancer treatment.

Maternal Protein Restriction Affects Postnatal Growth and the Expression of Key Proteins Involved in Lifespan Regulation in Mice

We previously reported that maternal protein restriction in rodents influenced the rate of growth in early life and ultimately affected longevity. Low birth weight caused by maternal protein restriction followed by catch-up growth (recuperated animals) was associated with shortened lifespan whereas protein restriction and slow growth during lactation (postnatal low protein: PLP animals) increased lifespan. We aim to explore the mechanistic basis by which these differences arise. Here we investigated effects of maternal diet on organ growth, metabolic parameters and the expression of insulin/IGF1 signalling proteins and Sirt1 in muscle of male mice at weaning. PLP mice which experienced protein restriction during lactation had lower fasting glucose (P = 0.038) and insulin levels (P = 0.046) suggesting improved insulin sensitivity. PLP mice had higher relative weights (adjusted by body weight) of brain (P = 0.0002) and thymus (P = 0.031) compared to controls suggesting that enhanced functional capacity of these two tissues is beneficial to longevity. They also had increased expression of insulin receptor substrate 1 (P = 0.021) and protein kinase C zeta (P = 0.046). Recuperated animals expressed decreased levels of many insulin signalling proteins including PI3 kinase subunits p85α (P = 0.018), p110β (P = 0.048) and protein kinase C zeta (P = 0.006) which may predispose these animals to insulin resistance. Sirt1 protein expression was reduced in recuperated offspring. These observations suggest that maternal protein restriction can affect major metabolic pathways implicated in regulation of lifespan at a young age which may explain the impact of maternal diet on longevity.

PI3-kinase and mitogen-activated protein kinase in cumulus cells mediate EGF-induced meiotic resumption of porcine oocyte

Previous studies have shown that epidermal growth factor (EGF) has the ability to promote in vitro cultured porcine oocyte maturation. However, little is known about the detailed downstream events in EGF-induced meiotic resumption. We designed this study to determine the relationship of EGF, EGFR, phosphatidylinositol 3-kinase (PI3-kinase), MAPK, and germinal vesicle breakdown (GVBD) during oocyte maturation. Our results showed that GVBD in cumulus-enclosed oocytes (CEOs) but not in denuded oocytes (DOs) was induced by EGF in a dose-dependent manner, which indicated that cumulus cells but not oocyte itself were the main target for EGF-induced meiotic resumption. Furthermore, we found that MAPK in cumulus cells rather than in oocyte was activated immediately after EGF administration. To explore whether EGF exerts its functions through MAPK pathway, the activities of EGF receptor (EGFR) and MAPK were inhibited by employing AG1478 and U0126, respectively. Inhibition of MAPK blocked EGF-induced GVBD, whereas inhibition of EGFR prevented MAPK activation. Both AG1478 and U0126 could lead to the failure of EGF-induced GVBD singly. Notably, we found that LY294002, a specific inhibitor of PI3-kinase, effectively inhibited EGF-induced MAPK activation as well as subsequent oocyte meiotic resumption and this inhibition could not be reversed by adding additional EGF. Thus, PI3-kinase-induced MAPK activation in cumulus cells mediated EGF-induced meiotic resumption in porcine CEOs. Together, this study provides evidences demonstrating a linear relationship of EGF/EGFR, PI3-kinase, MAPK and GVBD and presents a relatively definitive mechanism of EGF-induced meiotic resumption of porcine oocyte.

Clinical aspects of physical exercise for diabetes/metabolic syndrome

Evidence-based medicine (EBM) has come to be regarded as essential in all fields of medical sciences and practical medicine. In the field of diabetes and exercise, among the epidemiological studies of physical exercise, recent mega-trials such as the Diabetes Prevention Program (DPP) in the U.S. have shown that lifestyle intervention programs involving diet and/or exercise reduce the progression of impaired glucose tolerance (IGT) to type 2 diabetes. In studies examining the endocrinological and metabolic effects of exercise, it has been demonstrated that physical exercise promotes the utilization of blood glucose and free fatty acids in muscles and lowers blood glucose levels in well-controlled diabetic patients. Long-term, mild, regular jogging increases the action of insulin in both carbohydrate and lipid metabolism without influencing body mass index or maximal oxygen uptake. A significant correlation has been observed between delta MCR (Δinsulin sensitivity) and the average number of steps performed in a day. Our recent data suggested that the improved effectiveness of insulin that occurs as a result of physical exercise is attributable, at least in part, to increases in GLUT4 protein, IRS1 and PI3-kinase protein in skeletal muscle. As a prescription for exercise, aerobic exercise of mild to moderate intensity, including walking and jogging, 10–30 min a day, 3–5 days a week, is recommended. Resistance training of mild intensity with the use of light dumbbells and stretch cords should be combined in elderly individuals who have decreased muscle strength. An active lifestyle is essential in the management of diabetes, which is one of typical lifestyle-related diseases.

The adipose tissue triglyceride lipase ATGL/PNPLA2 is downregulated by insulin and TNF-α in 3T3-L1 adipocytes and is a target for transactivation by PPARγ

The minimal adipose phenotype of hormone-sensitive lipase (HSL)-null mice suggested that other hormonally responsive lipase(s) were present in adipocytes. Recent studies have characterized a new adipose tissue triglyceride lipase, ATGL/PNPLA2/destnutrin/iPLA2zeta/TTS2.2 (ATGL). We had previously cloned a novel adipose-enriched transcript by differential screening and recently determined its identity with murine ATGL. We report here on the regulation of ATGL by TNF-alpha and insulin in 3T3-L1 adipocytes and identify ATGL as a target for transcriptional activation by the key adipogenic transcription factor PPARgamma. Insulin at 100 nM resulted in a marked decrease in ATGL transcript that was effectively blocked by inhibitors for PI 3-kinase and p70 ribosomal protein S6 kinase. TNF-alpha treatment decreased ATGL transcript in a time-dependent manner that paralleled TNF-alpha downregulation of PPARgamma with a maximal decrease noted by 6 h. TNF-alpha effects on ATGL were attenuated by pretreatment with PD-98059, LY-294002, or rapamycin, suggesting involvement of the p44/42 MAP kinase, PI 3-kinase, and p70 ribosomal protein S6 kinase signals. To study transcriptional regulation of ATGL, we cloned 2,979 bp of the murine ATGL 5'-flanking region. Compared with promoterless pGL2-Basic, the -2979/+21 ATGL luciferase construct demonstrated 120- and 40-fold increases in activity in white and brown adipocytes, respectively. Luciferase reporter activities for a series of eight ATGL promoter deletions revealed that the -928/+21, -1738/+21, -1979/+21, and -2979/+21 constructs were transactivated by PPARgamma. Our findings identify the novel lipase ATGL to be a target gene for TNF-alpha and insulin action in adipocytes and reveal that it is subject to transcriptional control by PPARgamma-mediated signals.