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International Journal of Biological... 2016Crowding and changes in food availability are two critical environmental conditions that impact an animal's trajectory toward either migration or reproduction. Many...
Crowding and changes in food availability are two critical environmental conditions that impact an animal's trajectory toward either migration or reproduction. Many insects facing this challenge have evolved wing polyphenisms. When conditions favor reproduction, wing polyphenic species produce adults that either have no wings or short, non-functional wings. Facultative wing growth reflects a physiological and evolutionary trade-off between migration and reproduction, triggered by environmental conditions. How environmental cues are transduced to produce these alternative forms, and their associated ecological shift from migration to reproduction, remains an important unsolved problem in evolutionary ecology. The brown planthopper, a wing polymorphic insect exhibiting strong trade-offs in investment between migration and reproduction, is one of the most serious rice pests in Asia. In this study, we investigated the function of four genes in the insulin-signaling pathway known to couple nutrition with growth, PI3 Kinase (PI3K), PDK1, Akt (Protein Kinase B), and the forkhead gene FOXO. Using a combination of RNA interference and pharmacological inhibitor treatment, we show that all four genes contribute to tissue level regulation of wing polymorphic development in this insect. As predicted, silencing of the NlPI3K, NlAkt and NlPDK1 through dsRNA and with the pharmacological inhibitor Perifosine resulted in short-winged brown planthoppers, whereas knockdown of NlFOXO resulted in long-winged planthoppers. Morphometric analyses confirm that phenotypes from our manipulations mimic what would be found in nature, i.e., major parameters such as bristle number, wing area and body weight are not significantly different from non-experimental animals. Taken together, these data implicate the insulin-signaling pathway in the transduction of environmental factors into condition-dependent patterns of wing growth in insects.
Topics: Animal Migration; Animals; Female; Hemiptera; Male; Phosphatidylinositol 3-Kinases; Reproduction; Signal Transduction; Wings, Animal
PubMed: 27143957
DOI: 10.7150/ijbs.14802 -
Oncotarget Apr 2016DDX3 plays a dual role in colorectal cancer; however, the role and underlying mechanism of DDX3 in colorectal tumorigenesis remains unclear. Here, we provide evidence...
DDX3 plays a dual role in colorectal cancer; however, the role and underlying mechanism of DDX3 in colorectal tumorigenesis remains unclear. Here, we provide evidence that DDX3 enhances oncogenic KRAS transcription via an increase in SP1 binding to its promoter. Accelerating oncogenic KRAS expression by DDX3 promotes the invasion capability via the ERK/PTEN/AKT/β-catenin cascade. Moreover, the β-catenin/ZEB1 axis is responsible for DDX3-induced cell invasiveness and xenograft lung tumor nodule formation. The xenograft lung tumor nodules induced by DDX3-overexpressing T84 stable clone were nearly suppressed by the inhibitor of AKT (perifosine) or β-catenin (XAV939). Among patients, high KRAS, positive nuclear β-catenin expression and high ZEB1 were more commonly occurred in high-DDX3 tumors than in low-DDX3 tumors. High-DDX3, high-KRAS, positive nuclear β-catenin tumors, and high-ZEB1 exhibited worse overall survival (OS) and relapse free survival (RFS) than their counterparts. In conclusion, DDX3 may play an oncogenic role to promote tumor growth and invasion in colon cancer cells via the β-catenin/ZEB1 axis due to increasing KRAS transcription. We therefore suggest that AKT or β-catenin may potentially act as a therapeutic target to improve tumor regression and outcomes in colorectal cancer patients who harbored high-DDX3 tumors.
Topics: Animals; Colorectal Neoplasms; DEAD-box RNA Helicases; Gene Expression Regulation, Neoplastic; Heterografts; Humans; Kaplan-Meier Estimate; Mice; Neoplasm Invasiveness; Proto-Oncogene Proteins p21(ras); Zinc Finger E-box-Binding Homeobox 1; beta Catenin
PubMed: 27007150
DOI: 10.18632/oncotarget.8143 -
Drug Design, Development and Therapy 2015Ghrelin is a 28-amino-acid gut hormone that was first discovered as a potent growth hormone secretagogue. Recently, it has been shown to exert a strong anti-inflammatory...
BACKGROUND AND AIMS
Ghrelin is a 28-amino-acid gut hormone that was first discovered as a potent growth hormone secretagogue. Recently, it has been shown to exert a strong anti-inflammatory effect. The purpose of the study reported here was to explore the effect and mechanism of ghrelin on concanavalin (Con) A-induced acute hepatitis.
METHODS
Balb/C mice were divided into four groups: normal control (NC) (mice injected with vehicle [saline]); Con A (25 mg/kg); Con A + 10 μg/kg ghrelin; and Con A + 50 μg/kg ghrelin (1 hour before Con A injection). Pro-inflammatory cytokine levels were detected. Protein levels of phosphoinositide 3-kinase (PI3K); phosphorylated Akt (p-Akt); caspase 3, 8, and 9; and microtubule-associated protein 1 light chain 3 (LC3) were also detected. Perifosine (25 mM) (an Akt inhibitor) was used to investigate whether the protective effect of ghrelin was interrupted by an Akt inhibitor. Protein levels of p-AKT; Bcl-2; Bax; and caspase 3, 8, and 9 were also detected.
RESULTS
Aspartate aminotransferase, alanine aminotransferase, and pathological damage were significantly ameliorated by ghrelin pretreatment in Con A-induced hepatitis. Inflammatory cytokines were significantly reduced by ghrelin pretreatment. Bcl-2; Bax; and caspase 3, 8, and 9 expression were also clearly affected by ghrelin pretreatment, compared with the Con A-treated group. However, the Akt kinase inhibitor reversed the decrease of Bax and caspase 3, 8, 9, and reduced the protein level of p-Akt and Bcl-2. Ghrelin activated the PI3K/Akt/Bcl-2 pathway and inhibited activation of autophagy.
CONCLUSION
Our results demonstrate that ghrelin attenuates Con A-induced acute immune hepatitis by activating the PI3K/Akt pathway and inhibiting the process of autophagy, which might be related to inhibition of inflammatory cytokine release, and prevention of hepatocyte apoptosis. These effects could be interrupted by an Akt kinase inhibitor.
Topics: Animals; Anti-Infective Agents; Apoptosis; Apoptosis Regulatory Proteins; Autophagy; Chemical and Drug Induced Liver Injury; Concanavalin A; Cytokines; Cytoprotection; Disease Models, Animal; Ghrelin; Inflammation Mediators; Liver; Mice, Inbred BALB C; Necrosis; Signal Transduction; Time Factors
PubMed: 26451091
DOI: 10.2147/DDDT.S89096 -
PloS One 2015Although high density lipoprotein (HDL) improves the functions of endothelial progenitor cells (EPCs), the effect of HDL ApoAI mimetic peptide reverse-D-4F (Rev-D4F) on...
Although high density lipoprotein (HDL) improves the functions of endothelial progenitor cells (EPCs), the effect of HDL ApoAI mimetic peptide reverse-D-4F (Rev-D4F) on EPC mobilization and repair of EPC dysfunctions remains to be studied. In this study, we investigated the effects of Rev-D4F on peripheral blood cell subpopulations in C57 mice treated with a high fat diet and the mechanism of Rev-D4F in improving the function of EPCs impaired by tumor necrosis factor-α (TNF-α). The high fat diet significantly decreased the number of EPCs, EPC migratory functions, and the percentage of lymphocytes in the white blood cells. However, it significantly increased the number of white blood cells, the percentage of monocytes in the white blood cells, and the level of vascular endothelial growth factor (VEGF) and TNF-α in the plasma. Rev-D4F clearly inhibited the effect of the high fat diet on the quantification of peripheral blood cell subpopulations and cytokine levels, and increased stromal cell derived factor 1α (SDF-1α) in the plasma. We provided in vitro evidence that TNF-α impaired EPC proliferation, migration, and tube formation through inactive AKT and eNOS, which was restored by Rev-D4F treatment. In contrast, both the PI3-kinase (PI3K) inhibitor (LY294002) and AKT inhibitor (perifosine) obviously inhibited the restoration of Rev-4F on EPCs impaired by TNF-α. Our results suggested that Rev-D4F increases the quantity of endothelial progenitor cells through increasing the SDF-1α levels and decreasing the TNF-α level of peripheral blood in high fat diet-induced C57BL/6J mice, and restores TNF-α induced dysfunctions of EPCs partly through stimulating the PI3K/AKT signal pathway.
Topics: Animals; Cardiovascular Diseases; Cells, Cultured; Chemokine CXCL12; Diet, High-Fat; Drug Evaluation, Preclinical; Endothelial Progenitor Cells; Mice, Inbred C57BL; Nitric Oxide Synthase Type III; Peptides; Proto-Oncogene Proteins c-akt; Tumor Necrosis Factor-alpha
PubMed: 26398523
DOI: 10.1371/journal.pone.0138832 -
Oncotarget Sep 2015Most tumors circumvent telomere-length imposed replicative limits through expression of telomerase, the reverse transcriptase that maintains telomere length. Substantial...
Most tumors circumvent telomere-length imposed replicative limits through expression of telomerase, the reverse transcriptase that maintains telomere length. Substantial evidence that AKT activity is required for telomerase activity exists, indicating that AKT inhibitors may also function as telomerase inhibitors. This possibility has not been investigated in a clinical context despite many clinical trials evaluating AKT inhibitors. We tested if Perifosine, an AKT inhibitor in clinical trials, inhibits telomerase activity and telomere maintenance in tissue culture and orthotopic xenograft models as well as in purified CLL samples from a phase II Perifosine clinical trial. We demonstrate that Perifosine inhibits telomerase activity and induces telomere shortening in a wide variety of cell lines in vitro, though there is substantial heterogeneity in long-term responses to Perifosine between cell lines. Perifosine did reduce primary breast cancer orthotopic xenograft tumor size, but did not impact metastatic burden in a statistically significant manner. However, Perifosine reduced telomerase activity in four of six CLL patients evaluated. Two of the patients were treated for four to six months and shortening of the shortest telomeres occurred in both patients' cells. These results indicate that it may be possible to repurpose Perifosine or other AKT pathway inhibitors as a novel approach to targeting telomerase.
Topics: Animals; Breast Neoplasms; Cell Line, Tumor; Clinical Trials, Phase II as Topic; Enzyme Inhibitors; Female; Humans; Leukemia, Lymphocytic, Chronic, B-Cell; Mice; Mice, Inbred NOD; Mice, SCID; Neoplasms; Phosphorylcholine; Telomerase; Telomere; Xenograft Model Antitumor Assays
PubMed: 26307677
DOI: 10.18632/oncotarget.5200 -
Oncoscience 2015Sorafenib, a tyrosine kinase inhibitor, has been demonstrated to exert anti-tumor effects. However, the molecular mechanisms underlying its effects on bladder cancer...
Sorafenib induces cathepsin B-mediated apoptosis of bladder cancer cells by regulating the Akt/PTEN pathway. The Akt inhibitor, perifosine, enhances the sorafenib-induced cytotoxicity against bladder cancer cells.
Sorafenib, a tyrosine kinase inhibitor, has been demonstrated to exert anti-tumor effects. However, the molecular mechanisms underlying its effects on bladder cancer remain unknown. Here, we evaluated the mechanisms responsible for the sorafenib-induced anti-tumor effects on 5637 and T24 bladder cancer cells. We demonstrated that sorafenib reduces cell viability, stimulates lysosome permeabilization and induces apoptosis of bladder cancer cells. These effects are dependent by the activation of cathepsin B released from lysosomes. The sorafenib-increased cathepsin B activity induced the proteolysis of Bid into tBid that stimulates the intrinsic pathway of apoptosis characterized by mitochondrial membrane depolarization, oxygen radical generation and cytochrome c release. Moreover, we found that cathepsin B enzymatic activity, induced by sorafenib, is dependent on its dephosphorylation via PTEN activation and Akt inactivation. Pretreatment with orthovanadate rescued bladder cancer cells from apoptosis. In addition, the Akt inhibitor perifosine increased the sensitivity of bladder cancer cells to sorafenib-induced cytotoxicity. Overall, our results show that apoptotic cell death induced by sorafenib in bladder cancer cells is dependent on cathepsin B activity and involved PTEN and Akt signaling pathways. The Akt inhibitor perifosine increased the cytotoxic effects of sorafenib in bladder cancer cells.
PubMed: 26097873
DOI: 10.18632/oncoscience.147 -
Oncotarget Jun 2015Ewing's sarcoma (ES) is the second most common bone cancer in children and young people. Edelfosine (1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine) is the...
Ewing's sarcoma (ES) is the second most common bone cancer in children and young people. Edelfosine (1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine) is the prototype of a family of synthetic antitumor compounds, collectively known as alkylphospholipid analogs (APLs). We have found that APLs ranked edelfosine>perifosine>erucylphosphocholine>miltefosine for their capacity to promote apoptosis in ES cells. Edelfosine accumulated in the endoplasmic reticulum (ER) and triggered an ER stress response that eventually led to caspase-dependent apoptosis in ES cells. This apoptotic response involved mitochondrial-mediated processes, with cytochrome c release, caspase-9 activation and generation of reactive oxygen species. Edelfosine-induced apoptosis was also dependent on sustained c-Jun NH2-terminal kinase activation. Oral administration of edelfosine showed a potent in vivo antitumor activity in an ES xenograft animal model. Histochemical staining gave evidence for ER stress response and apoptosis in the ES tumors isolated from edelfosine-treated mice. Edelfosine showed a preferential action on ES tumor cells as compared to non-transformed osteoblasts, and appeared to be well suited for combination therapy regimens. These results demonstrate in vitro and in vivo antitumor activity of edelfosine against ES cells that is mediated by caspase activation and ER stress, and provide the proof of concept for a putative edelfosine- and ER stress-mediated approach forES treatment.
Topics: Animals; Antineoplastic Agents; Apoptosis; Bone Neoplasms; Endoplasmic Reticulum; Humans; Mice; Mice, SCID; Phospholipid Ethers; Sarcoma, Ewing; Xenograft Model Antitumor Assays
PubMed: 25999349
DOI: 10.18632/oncotarget.4053 -
Oncotarget Mar 2015T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive neoplastic disorder in which chemotherapy resistance and refractory relapses occur, with a poorer prognostic...
T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive neoplastic disorder in which chemotherapy resistance and refractory relapses occur, with a poorer prognostic outcome.Constitutively active PI3K/Akt/mTOR pathway is a common feature of T-ALL upregulating cell proliferation, survival and drug resistance. This pathway is currently under clinical trials with small molecules inhibitors (SMI).To verify whether a multi-inhibition treatment against Akt protein could enhance the efficacy of individual drug administration and overcome drug resistance as well as to obtain a decrease in single drug concentration, we tested on T-ALL cell lines the effects of combined treatments with three Akt inhibitors with different mode of action, GSK690693, MK-2206 and Perifosine.In cells with hyperactivated Akt, combined administration of the drugs displayed a significant synergistic and cytotoxic effect and affected PI3K/Akt/mTOR pathway at much lower concentration than single drug use. Highest synergistic effect for full inhibition of Akt was also related to the timing of every drug administration. Furthermore the triple treatment had greater efficacy in inducing cell cycle arrest in G0/G1 phase and both apoptosis and autophagy.Targeting Akt as a key protein of PI3K/Akt/mTOR pathway with multiple drugs might represent a new and promising pharmacological strategy for treatment of T-ALL patients.
Topics: Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Autophagy; Cell Cycle Checkpoints; Dose-Response Relationship, Drug; Drug Synergism; Enzyme Activation; Heterocyclic Compounds, 3-Ring; Humans; Jurkat Cells; Molecular Targeted Therapy; Oxadiazoles; Phosphatidylinositol 3-Kinase; Phosphorylation; Phosphorylcholine; Precursor T-Cell Lymphoblastic Leukemia-Lymphoma; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Signal Transduction; TOR Serine-Threonine Kinases
PubMed: 25788264
DOI: 10.18632/oncotarget.3260 -
Cancer Chemotherapy and Pharmacology May 2015Central nervous system tumors are histologically and biologically heterogeneous. Standard treatment for malignant tumors includes surgery, radiation and chemotherapy,...
PURPOSE
Central nervous system tumors are histologically and biologically heterogeneous. Standard treatment for malignant tumors includes surgery, radiation and chemotherapy, yet surgical resection is not always an option and chemotherapeutic agents have limited benefit. Recent investigations have focused on molecularly targeted therapies aimed at critical tumorigenic pathways. Several tumor types, including high-grade gliomas and pediatric pontine gliomas, exhibit Akt activation. Perifosine, an orally bioavailable, synthetic alkylphospholipid and potent Akt inhibitor, has demonstrated activity in some preclinical models, but absent activity in a genetically engineered mouse model of pontine glioma. We evaluated the plasma and cerebrospinal fluid pharmacokinetics of orally administered perifosine in a non-human primate model to evaluate CNS penetration.
METHODS
Perifosine was administered orally to three adult rhesus monkeys as a single dose of 7.0 mg/kg perifosine. Serial paired plasma and CSF samples were collected for up to 64 days. Perifosine was quantified with a validated HPLC/tandem mass spectrometry assay. Pharmacokinetic parameters were estimated using non-compartmental methods. CSF penetration was calculated from the areas under the concentration-time curves.
RESULTS
Peak plasma concentrations (C max) ranged from 11.7-19.3 µM, and remained >1 µM for >28 days. Time to C max (T max) was 19 h. The median (range) AUCPl was 3148 (2502-4705) µM/h, with a median (range) terminal half-life (t 1/2) of 193 (170-221) h. Plasma clearance was 494 (329-637) mL/h/kg. Peak CSF concentrations were 4.1-10.1 nM (T max 64-235 h). CSF AUCs and t 1/2 were 6358 (2266-7568) nM/h and 277 (146-350) h, respectively. Perifosine concentrations in the CSF remained over nM for >35 days. The mean CSF penetration was 0.16 %.
CONCLUSION
CNS penetration of perifosine after systemic administration is poor. However, levels were measurable in both plasma and CSF for an extended time (>2 months) after a single oral dose.
Topics: Administration, Oral; Animals; Macaca mulatta; Male; Models, Animal; Phosphorylcholine; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-akt
PubMed: 25740692
DOI: 10.1007/s00280-015-2711-1 -
Molecular Cancer Research : MCR Apr 2015The aim of this study was to determine the role of AKT as a therapeutic target in ovarian clear cell carcinoma (CCC), an aggressive, chemoresistant histologic subtype of...
UNLABELLED
The aim of this study was to determine the role of AKT as a therapeutic target in ovarian clear cell carcinoma (CCC), an aggressive, chemoresistant histologic subtype of ovarian cancer. AKT activation was assessed by immunohistochemistry (IHC) using human tissue microarrays of primary ovarian cancers, composed of both CCC and serous adenocarcinoma (SAC). The growth-inhibitory effect of AKT-specific targeting by the small-molecule inhibitor, perifosine, was examined using ovarian CCC cell lines in vitro and in vivo. Finally, the activity of perifosine was examined using in CCC-derived tumors that had acquired resistance to anti-VEGF or chemotherapeutics such as bevacizumab or cisplatin, respectively. Interestingly, AKT was frequently activated both in early-stage and advanced-stage CCCs. Treatment of CCC cells with perifosine attenuated the activity of AKT-mTORC1 signaling, inhibited proliferation, and induced apoptosis. The effect of perifosine was more profound under conditions of high AKT activity compared with low AKT activity. Increased AKT activation and enhanced sensitivity to perifosine were observed in the context of cisplatin-resistant CCC. Treatment with perifosine concurrently with cisplatin significantly enhanced the antitumor effect of cisplatin. Moreover, perifosine showed significant antitumor activity in CCC-derived tumors that had acquired resistance to bevacizumab or cisplatin. Collectively, these data reveal that AKT is frequently activated in ovarian CCCs and is a promising therapeutic target in aggressive forms of ovarian cancer.
IMPLICATIONS
AKT-targeted therapy has value in a first-line setting as well as a second-line treatment for recurrent disease developing after platinum-based chemotherapy or bevacizumab treatment.
Topics: Adenocarcinoma, Clear Cell; Animals; Antineoplastic Agents; Cell Line, Tumor; Cisplatin; Drug Resistance, Neoplasm; Drug Synergism; Female; Humans; Mechanistic Target of Rapamycin Complex 1; Mice; Multiprotein Complexes; Ovarian Neoplasms; Phosphorylcholine; Proto-Oncogene Proteins c-akt; Signal Transduction; TOR Serine-Threonine Kinases; Xenograft Model Antitumor Assays
PubMed: 25519148
DOI: 10.1158/1541-7786.MCR-14-0314