Akt Enzyme Research Articles

Oxidative Stress Induced by Cortisol in Human Platelets.

Hypercortisolism is known to affect platelet function. However, few studies have approached the effect of exogenous cortisol on human platelets, and the results obtained are conflicting and unconvincing. In this study, the effect of exogenous cortisol on several parameters indicative of oxidative status in human platelets has been analysed. We have found that cortisol stimulates ROS production, superoxide anion formation, and lipid peroxidation, with these parameters being in strict correlation. In addition, cortisol decreases GSH and membrane SH-group content, evidencing that the hormone potentiates oxidative stress, depleting platelet antioxidant defence. The involvement of src, syk, PI3K, and AKT enzymes in oxidative mechanisms induced by cortisol is shown. The main sources of ROS in cells can include uncontrolled increase of NADPH oxidase activity and uncoupled aerobic respiration during oxidative phosphorylation. Both mechanisms seem to be involved in ROS formation induced by cortisol, as the NADPH oxidase 1 inhibitor 2(trifluoromethyl)phenothiazine, and rotenone and antimycin A, complex I and III inhibitor, respectively, significantly reduce oxidative stress. On the contrary, the NADPH oxidase inhibitor gp91ds-tat, malate and NaCN, complex II and IV inhibitor, respectively, have a minor effect. It is likely that, in human platelets, oxidative stress induced by cortisol can be associated with venous and arterial thrombosis, greatly contributing to cardiovascular diseases.

Design, synthesis and evaluation of acridone-2-carbohydrazide derivatives as p-AKT Ser473 kinase inhibitors.

Aim: A series of benzylidene- and phenylethylidene-substituted acridone-2-carbohydrazide derivatives were designed, synthesized and evaluated for their cytotoxicity and response to p-AKT Ser473. Methods: The structures of the synthesized compounds were confirmed by spectroscopic techniques and evaluated for AKT enzyme inhibition activities. Molecular docking and in silico absorption, distribution, metabolism, elimination and toxicity studies were also performed. Results: Compounds 8k, 8v and 9h demonstrated good cytotoxicity against breast cancer cell lines. Especially, compounds 8v and 9h exhibited remarkable inhibition, with IC50 values of 1.75 and 2.40 μM, respectively. These compounds inhibited p-AKT Ser473 more specifically than total AKT in a dose-dependent manner. Moreover, they caused G0/G1-phase cell cycle arrest and cell apoptosis. Conclusion: This study identified compound 8v as a potent p-AKT Ser473 inhibitor.

BTEAC Catalyzed Ultrasonic-Assisted Synthesis of Bromobenzofuran-Oxadiazoles: Unravelling Anti-HepG-2 Cancer Therapeutic Potential through In Vitro and In Silico Studies.

In this work, BTEAC (benzyl triethylammonium chloride) was employed as a phase transfer catalyst in an improved synthesis (up to 88% yield) of S-alkylated bromobenzofuran-oxadiazole scaffolds BF1-9. These bromobenzofuran-oxadiazole structural hybrids BF1-9 were evaluated in vitro against anti-hepatocellular cancer (HepG2) cell line as well as for their in silico therapeutic potential against six key cancer targets, such as EGFR, PI3K, mTOR, GSK-3β, AKT, and Tubulin polymerization enzymes. Bromobenzofuran structural motifs BF-2, BF-5, and BF-6 displayed the best anti-cancer potential and with the least cell viabilities (12.72 ± 2.23%, 10.41 ± 0.66%, and 13.08 ± 1.08%), respectively, against HepG2 liver cancer cell line, and they also showed excellent molecular docking scores against EGFR, PI3K, mTOR, and Tubulin polymerization enzymes, which are major cancer targets. Bromobenzofuran-oxadiazoles BF-2, BF-5, and BF-6 displayed excellent binding affinities with the active sites of EGFR, PI3K, mTOR, and Tubulin polymerization enzymes in the molecular docking studies as well as in MMGBSA and MM-PBSA studies. The stable bindings of these structural hybrids BF-2, BF-5, and BF-6 with the enzyme targets EGFR and PI3K were further confirmed by molecular dynamic simulations. These investigations revealed that 2,5-dimethoxy-based bromobenzofuran-oxadiazole BF-5 (10.41 ± 0.66% cell viability) exhibited excellent cytotoxic therapeutic efficacy. Moreover, computational studies also suggested that the EGFR, PI3K, mTOR, and Tubulin polymerization enzymes were the probable targets of this BF-5 scaffold. In silico approaches, such as molecular docking, molecular dynamics simulations, and DFT studies, displayed excellent association with the experimental biological data of bromobenzofuran-oxadiazoles BF1-9. Thus, in silico and in vitro results anticipate that the synthesized bromobenzofuran-oxadiazole hybrid BF-5 possesses prominent anti-liver cancer inhibitory effects and can be used as lead for further investigation for anti-HepG2 liver cancer therapy.

Extracellular vesicles regulate the transmission of insulin resistance and redefine noncommunicable diseases.

Noncommunicable diseases (NCDs), such as diabetes and related neurological disorders, are considered to not be directly transmissible from one person to another. However, NCDs may be transmissible in vivo through extracellular vesicles (EVs). A long-term high-fat diet (HFD) can induce a series of health issues like hyperlipidemia, type 2 diabetes mellitus (T2DM), and diabetic peripheral neuropathy (DPN) due to insulin resistance. Multiple molecular signaling changes can stimulate insulin resistance, especially blocking insulin signaling by increased insulin resistance inducer (phosphorylation of negative regulatory sites of insulin receptor substrate (IRS) proteins) and decreased tyrosine phosphorylation of insulin receptor substrate (phosphorylation of positive regulatory sites of IRS), thus leading to reduced phosphorylation of AKT enzymes. Current efforts to treat T2DM and prevent its complications mainly focus on improving insulin sensitivity, enhancing insulin secretion, or supplementing exogenous insulin based on a common assumption that insulin resistance is noncommunicable. However, insulin resistance is transmissible within multiple tissues or organs throughout the body. Exploring the regulatory roles of EVs in developing insulin resistance may provide novel and effective preventive and therapeutic strategies.

Thrombin-Induced Oxidative Phosphorylation in Platelets Is Repressed By Dengue Virus through Inhibition of the PI3K/Akt Signaling Pathway

Background:There are many very important events that condition the progression to severe dengue, these include cytokine storm and a profound thrombocytopenia. Still, the molecular mechanisms underlying these events are not fully understood. Increasing evidence supports the fact that platelet dysfunction, in patients with dengue, could be due to direct interaction between platelets and dengue virus. This event induces changes in platelet function and contributes to pathogenesis. Recent results from our laboratory have shown that thrombin induces oxygen consumption through activation of glycoprotein Ib and subsequent phosphorylation of PI3K and Akt enzymes. Here we want to evaluate changes in these signalling pathways as well as their impact on mitochondrial function.Aims: To evaluate DENV2 effects on platelet function, PI3K/Akt signaling, oxidative phosphorylation and GPIb expression.Methods:Blood samples from healthy volunteers were collected and platelet fraction was obtained. Purified DENV2 particles were incubated with platelets for 2 h at 37ºC. Then, morphological changes, activation and aggregation, mitochondrial function and surface markers expression were tested in platelets.Results:We found that DENV2 induces conspicuous morphological changes on platelets not induced by other arboviruses; increases CD41 (p<0.05), CD62P (8979 ± 1189 vs1723 ± 160 MFI; p<0.05) and reduces CD42b (p<0.5) expressions on platelet surface; reduces agonist-induced platelet aggregation (30 ± 10 vs 71 ± 9%; p<0.05) through increases intracellular NO production (0.4 ± 0.2 vs 0.07 ± 0.01; p<0.05); inhibits thrombin-induced oxidative phosphorylation (45 ± 6.69 vs 348 ± 26.9 ngatomO/min/10 9 platelets; p<0.0001) through PI3K/Akt signaling pathways inhibition (p<0.001). Surprisingly, rDC-SIGN treatment reverts DENV2 effects on platelet activation (9693 ± 1033 vs 2379 ± 390 MFI; p<0.01).Conclusions:DENV2 inhibits thrombin-induced oxidative phosphorylation through PI3K/Akt signaling pathway inhibition. Dengue virus inhibits thrombin-induced phosphorylation at different levels in the platelet. First, by reducing the expression of the GPIb molecule on the platelet surface. This molecule is important for thrombin-induced intracellular signalling. Second, dengue virus inhibits the PI3K/Akat signalling pathway, which is important for the induction of oxidative phosphorylation in mitochondria. And third, dengue virus increases intracellular nitric oxide levels and promotes its excretion into the extracellular milieu, this mechanism could be involved in the inhibition of platelet aggregation processes.These changes induce by short-term interaction of platelets with DENV2 has a direct effect over platelet function and may be correlated with the clinical manifestations observed during severe dengue stage, such as thrombocytopenia and hemorrhages. The overall impact of these changes in signaling pathways related to immune activity remains to be determinate, as does the potential to develop new pharmacological treatments. DisclosuresNo relevant conflicts of interest to declare.

Structure activity evaluation and computational analysis identify potent, novel 3-benzylidene chroman-4-one analogs with anti-fungal, anti-oxidant, and anti-cancer activities

Significance 3-Benzylidene chroman-4-ones share close homology with naturally occurring bioactive compounds. Objectives This study evaluated the antifungal, antioxidant, and anticancer activities of novel 3-benzylidene chromanone analogs with respect to their structure–activity relationships. Methods Compounds 45e–64e were synthesized inhouse. Aspergillus niger (MTCC 1344) Aspergillus flavus and Botrytis cinerea were the fungal strains tested. Computational docking analysis was carried out for vanin-1, estrogen receptor (ER), and Akt proteins using Auto-dock vina. Free radical scavenging and total antioxidant capacity was analyzed using spectrophotometric methods. MCF-7 (breast cancer) cell line was used for anticancer assays. Flow cytometry was used to detect cell cycle and apoptosis. Results Out of the twenty compounds screened, compounds 47e, 50e, 52e, 57e, and 61e that possessed either methoxy and ethoxy/methyl/isopropyl group exhibited very good activity against all fungi. Compounds possessing methoxy group alone showed moderate activity and compounds devoid of methoxy, and ethoxy groups did not show any activity. When computationally analyzed against target proteins for antioxidant properties, the compounds exhibited excellent binging efficacy to vanin-1 and ERs. These predictions were translated in the in vitro free-radical scavenging and antioxidant assays. The compounds exhibited anti-proliferative efficacy in breast cancer cell line, increased the sub-G 0/G 1 cell cycle populations and total apoptosis in MCF-7 cells. Additionally, the compounds also depicted excelling binging energy when computationally analyzed for Akt enzyme binding. Conclusion In summary, our study identified potential analogs of 3-benzylidene chroman-4-one molecules with excellent anti-fungal, anti-oxidant, and anticancer activities which demand further research for drug developments.

Computational docking and in vitro analysis identifies novel arylidene analogue FPMXY-14 against renal cancer cells by attenuating Akt.

Targeted therapies are gaining global attention to tackle Renal Cancer (RC). This study aims to screen FPMXY-14 (novel arylidene analogue) for Akt inhibition by computational and in vitro methods. FPMXY-14 was subjected to proton NMR analysis and Mass spectrum analysis. Vero, HEK-293, Caki-1, and A498 cell lines were used. Akt enzyme inhibition was studied with the fluorescent-based kit assay. Modeller 9.19, Schrodinger 2018-1, LigPrep module, and Glide docking were used in computational analysis. The nuclear status was assessed by PI/Hoechst-333258 staining, cell cycle, and apoptosis assays were performed using flow cytometry. Scratch wound and migrations assays were performed. Western blotting was applied to study key signalling proteins. FPMXY-14 selectively inhibited kidney cancer cell proliferation with GI50 values of 77.5 nM and 101.40 nM in Caki-1 cells and A-498 cells, respectively. The compound dose-dependently inhibited Akt enzyme with an IC50 value of 148.5 nM and bound efficiently at the allosteric pocking of the Akt when computationally analyzed. FPMXY-14 caused nuclear condensation/fragmentation, increased the sub G0/G1, G2M populations, and induced early, late phase apoptosis in both cells when compared to controls. Treatment of the compound inhibited wound healing and migration of tumor cells, while proteins like Bcl-2, Bax, and caspase 3 were also altered. FPMXY-14 effectively inhibited the phosphorylation of Akt in these cancer cells, while total Akt was unaltered. FPMXY-14 exhibited anti-proliferative and anti-metastatic activities in kidney cancer cells by attenuating the Akt enzyme. Further pre-clinical research on animals with a detailed pathway elucidation is recommended.

Akt‐PI3K signaling pathway is a crucial player in dopamine D2 receptor‐mediated emesis in least shrews

Dopamine is a member of the catecholamine family involved in multiple physiological functions. Together with its five dopaminergic receptors (DRs), DA is associated with several neurological diseases including restless leg syndrome, schizophrenia, Parkinson’s disease, and depression. Unfortunately, most DR‐based agonists used to treat some of these diseases evoke nausea and vomiting as impending side‐effects. Coincidently, activation of the kinase phosphoinositide 3‐kinase (PI3K)/protein kinase B (Akt) pathway not only plays a significant role in the onset and the progression of neurodegenerative disorders but may also evoke emesis caused by stimulation of dopamine D2 receptor (DR2). Thus, the aim of this study was to decipher the role of Akt in DR2‐induced emesis using the least shrew model of vomiting (Cryptotis parva). Shrews were injected intraperitoneally (i.p.) with a fully effective emetic dose of the DR2 preferring agonist quinpirole (2 mg/kg) in the presence and the absence of either: i) a corresponding DR2 antagonist sulpiride (subcutaneous (s.c.), 8 mg/kg), or ii) incremental doses of the PI3K inhibitor LY294002 (0, 5, 10 mg/kg, i.p.). The treated shrews were observed for 30 mins for vomiting behavior following quinpirole injection. Another set of shrews were treated with 2 mg/kg quinpirole alone (N = 4 per group) and sacrificed at 5, 15, and 30 mins to determine the time‐dependent profile of Akt phosphorylation. The animals were then perfused, and brains collected for immunohistochemistry studies or brainstems harvested for Western blot analysis on protein extracts. For antagonist studies, different groups of shrews were given sulpiride (8 mg/kg, s.c) or LY294002 (10 mg/kg, i.p.) (N = 4–6 per group) for 30 mins prior to injection of quinpirole (2 mg/kg) and brainstems were collected after 15 mins for Western blot analysis. Behavioral results showed that quinpirole induced vomiting was significantly blocked by sulpiride (8 mg/kg) and LY296004 (10 mg/kg). Akt phosphorylation at Ser473 was significantly increased at 15 and 30 mins in the brainstem with quinpirole treatment alone. The increase of phospho‐Akt protein in brainstem emetic nuclei [area postrema (AP), nucleus of the solitary tract (NTS), and dorsal motor nucleus of the vagus (DMNX)] was further confirmed through immunostaining brainstem sections of quinpirole‐treated least shrews. Sulpiride on the other hand significantly inhibited quinpirole‐induced Akt and PI3K protein phosphorylation at 15 mins. Likewise, LY29004 prevented Akt activation at 15 mins. Our findings uncovered a crucial role for DR2‐mediated Akt activation in emesis and suggest targeting signals up upstream of Akt enzyme may offer new avenues for potential potent antiemetics.Support or Funding InformationThis work was supported in part by NIH‐NCI grant RO1CA207287 and the WesternU startup fund (1395) to ND.

Synthesis, Molecular Docking and Biological Evaluation of Novel Flavone Derivatives as Potential Anticancer Agents Targeting Akt

Flavonoids are naturally occurring compounds with versatile healthpromoting effects against various diseases. This aim of this paper is to synthesize and evaluate the biological activity of novel flavone derivatives against cancer. A new series of 2-hydroxy-α,β-unsaturated ketones 2a-h, was synthesized via the reaction of N-substituted-indole-3-carboxaldehyde 1a-h with 2-hydroxy acetophenone in the presence of piperidine. The oxidative cyclization of 2a-h using hydrogen peroxide/KOH and/or dimethyl sulfoxide/I2 produced the corresponding 2-(N-substituted-1H-indol-3-yl)-3-hydroxy-4H-chromen- 4-ones 3a-h and 2-(N-substituted-1H-indol-3-yl)-4H-chromen-4-ones 4a-h, respectively. Antiproliferative activities for synthesized series were investigated against HCT-116 colon and MCF- 7 breast cancer cell lines. Molecular downstream effects were evaluated using RT-PCR. Moreover, molecular docking was carried out to pinpoint the binding mode of the most active compounds into the active site of Akt enzyme (PDB ID: 3QKK). All compounds exhibited an anti-proliferative activity range of 52-97% and 67.2-99% against HCT-116 and MCF-7, respectively. Compounds 3b, 3h, 3g and 4h had a minimal inhibitory effect on normal BJ1 cells indicating their safety profile. Compounds 3b and 4h, in particular, exhibited the most potent antiproliferative activity against HCT116 and MCF7, meanwhile compounds 3g, 3h and 4g showed potent to moderate activity. Compound 3b had IC50 of 78.3 μM and 53.9 μM against HCT-116 and MCF-7 respectively with comparable IC50 for doxorubicin of 65.1 μM and 45.02 μM. Compound 3b exhibited significant down-regulation for Akt and significant up-regulation of CAS9 and CDKN1genes in all tested cell lines. The synthesized flavone derivatives and particularly compound 3b exhibited promising anticancer activity through Akt inhibition.

Comprehensive Study on Thiadiazole-Based Anticancer Agents Inducing Cell Cycle Arrest and Apoptosis/Necrosis Through Suppression of Akt Activity in Lung Adenocarcinoma and Glioma Cells.

Akt is considered as an attractive target for anticancer drug discovery and development and therefore extensive efforts have been devoted to the discovery of new potent anticancer agents targeting Akt. Due to the importance of thiadiazoles for anticancer drug discovery, herein eight 1,3,4-thiadiazole derivatives were investigated for their cytotoxic effects on C6 rat glioma and A549 human lung adenocarcinoma cell lines using the MTT assay. The effects of the most promising anticancer agents on apoptosis, caspase-3 activation, mitochondrial membrane potential, and cell cycle arrest were determined on a BD FACSAria (I) flow cytometer. Akt activity was measured in the C6 and A549 cell lines using an ELISA colorimetric method. Schrödinger's Maestro molecular modeling package was used to explore the possible binding modes of compounds 3 and 8 in the active site of Akt enzyme (PDB code: 3OW4). N-(4-Chlorophenyl)-2-[(5-((4-nitrophenyl)amino)-1,3,4-thiadiazol-2-yl)thio]acetamide (3) and N-(6-nitrobenzothiazol-2-yl)-2-[(5-((4- nitrophenyl)amino)-1,3,4-thiadiazol-2-yl)thio]acetamide (8) induced apoptosis and cell cycle arrest in the C6 cell line through inhibition of Akt activity (92.36% and 86.52%, respectively). The docking results of compounds 3 and 8 indicated that π-π interactions, H bonds, and salt-bridge formation were responsible for the observed Akt inhibitory activity. According to in vitro and docking studies, compounds 3 and 8 stand out as promising antiglioma agents.

Design, Synthesis, and Evaluation of a New Series of Thiazole-Based Anticancer Agents as Potent Akt Inhibitors.

In an attempt to develop potent anticancer agents targeting Akt, new thiazole derivatives (1–10) were synthesized and investigated for their cytotoxic effects on A549 human lung adenocarcinoma, C6 rat glioma, and NIH/3T3 (healthy) mouse embryonic fibroblast cell lines. The most potent compounds were also investigated for their effects on apoptosis and Akt pathway. The most promising anticancer agent was found to be 2-[2-((4-(4-cyanophenoxy)phenyl)methylene)hydrazinyl]-4-(4-cyanophenyl)thiazole (6), due to its selective inhibitory effects on A549 and C6 cells with IC50 values of 12.0 ± 1.73 µg/mL and 3.83 ± 0.76 µg/mL, respectively. Furthermore, compound 6 increased early and late apoptotic cell population (32.8%) in C6 cell line more than cisplatin (28.8%) and significantly inhibited the Akt enzyme. The molecular docking study was performed to predict the possible binding modes of compounds A, 6, and 8 inside the active site of Akt (PDB code: 4EJN). Molecular docking simulations were found to be in accordance with in vitro studies and, hence, supported the biological activity. A computational study for the prediction of absorption, distribution, metabolism and excretion (ADME) properties of all compounds was also performed. On the basis of Lipinski’s rule of five, the compounds were expected to be potential orally bioavailable agents.

Volatile Inhibitors of Phosphatidylinositol-3-Kinase (PI3K) Pathway: Anticancer Potential of Aroma Compounds of Plant Essential Oils.

Cancer is a grave health problem for the world as the global cancer burden rises to 14 million new cases with 8.2 million deaths every year which is expected to rise by 70% in the next 2 decades as reported by the WHO.These steady rises in death demand for rapid developments in anti-cancer agents. Essential oils, being natural and multi-component complex systems have recently attracted a lot of attention in this search for novel anti-cancer agents. The pharmaceutical attributes of essential oil components, specifically focusing on their affinity towards COX, 5-LOX, AKT, MDM2, PDK1 and mTOR which defines the phosphatidylinositol-3- kinase (PI3K) pathway, were assessed. 123 compounds present in essential oils of different plants were analyzed for their drug like attributes which were then allowed to dock with PI3K dependent receptors crucial for the development of cancer malignancies. Among them, 21 compounds were filtered possessing high druglikeness with favourable metabolism offered by major cytochromeP450 isoforms. Finally, the best docked compounds with highest binding affinities were employed for building a ligand based pharmacophore. Being inhibitors of P-glycoproteins, these molecules also exhibited good absorption profiles and noncarcinogenic properties. Further from these 21, six compounds were evaluated against A549 lung cancer cells. The pharmacophoric feature obtained can be applied for both designing and screening moieties for active inhibitors of the phosphatidylinositol-3-kinase pathway specifically from essential oil compounds and these final 21 compounds can be further promoted to studies for anti-cancer drug development. Among these, six compounds exhibited promising inhibitory results against A549 lung cancer cells. Furthermore, immunoblotting assay confirmed the efficacy of the compounds for inhibiting mTOR and AKT enzymes which are bandmasters for downstream signaling of thePI3K pathway. Methyl nonanoate, (R)-citronellol, cis-carveol (L-carveol), 3-methyl-Cyclohexanone, 4-carene and thujopsene were finally screened for PI3K targeted anti-cancer therapies which may find direct application as inhalers or sprays against lung cancer as these compounds are highly volatile.

IOX-101, a novel small molecule, reduces AML cell proliferation by Akt enzyme inhibition

Cancer of the blood continues to be a major mortality factor globally. Arylidene compounds are well known for their anticancer effects. Here we describe the biological efficacy of IOX-101, a potential lead-compound of arylidene in acute myeloid leukemia (AML). Initially, molecular docking analysis was performed to check the binding efficacy of the compound with protein kinase B (Akt). The ability of the molecule to inhibit AML proliferation was assessed in THP-1 and Kasumi-6 cells by a standard MTT assay. Hoechst 333258/propidium iodide (PI) staining was carried out to analyze the nuclear damage. Flow cytometry was performed to check the apoptotic and cell cycle changes in THP-1 cells. The effect of IOX-101 on Akt phosphorylation was assessed by Western blot analysis. Molecular docking revealed interaction and binding of IOX-101 with the active site of Akt enzyme. The compound reduced proliferation of both AML cell lines in a dose-responsive way. Nuclear staining and cell cycle results revealed DNA damage by IOX-101 in THP-1 cells, and a significant increase in early and late phase apoptotic cells. A dose-dependent dephosphorylation of Akt (Ser 473) by IOX-101 was observed, which indicated allosteric inhibition of Akt by the compound. Our results showed that the DNA damage-mediated antiproliferative effect of IOX-101 in AML cells was mediated by Akt enzyme inhibition, and that this molecule possesses an effective chemotherapeutic potential against AML. https://doi.org/10.2298/ABS170922049R Received: September 22, 2017; Revised: November 1, 2017; Accepted: November 7, 2017; Published online: November 28, 2017 How to cite this article: Rajagopalan Prasanna, Raju M, Aseeri H, Helal IM, Elbessoumy AA. IOX-101, a novel small molecule, reduces AML cell proliferation by Akt enzyme inhibition. Arch Biol Sci. 2018;70(2):321-7.

Biological evaluation of 2-arylidene-4, 7-dimethyl indan-1-one (FXY-1): a novel Akt inhibitor with potent activity in lung cancer.

Human lung cancer is contributed to be a major mortality factor in the cancer-related deaths. Arylidene indan-ones constitute a new class of potential anti-tumor compounds. Herein, we report the biological efficacy of the 2-arylidene-4, 7-dimethyl indan-1-one (FXY-1), a potential lead molecule of arylidene indan-ones in lung cancer models. We previously described anticancer activity of FXY-1 against human breast adenocarcinoma. FXY-1 efficacy was assessed by standard anticancer screening in NCI-H 460, A549, NCI-H 1975 and NCI-H 2170 cells. Initial molecular docking analysis was performed to check the interaction of compound to Akt enzyme. Anti-proliferation, anti-metastatic and transendothelial cell migration were performed to check efficacy of the drug. Western blot analysis was performed to understand the regulation of pro-apoptotic and anti-apoptotic proteins by the compound. The effect of FXY-1 on caspase induction and Akt phosphorylation were checked using Western blot analysis. Flow cytometry was used to reveal the cell cycle changes and apoptosis-inducing properties of FXY-1 in the lung cancer cells. In-vitro Akt inhibition property of the compound was studied using a fluorescence-based, coupled-enzyme reaction. The in-vivo efficacy of the compound was determined using a mouse xenograft model. Our molecular docking analysis reveals higher interaction of FXY-1 with Akt. FXY-1 depicted anti-proliferative and pro-apoptotic activity with higher therapeutic window in-vitro in NCI-H 460 and A549 cells. The compound treatment to lung cancer cells resulted in induction of DNA fragmentation, inhibition of transendothelial migration, caspase activation and poly (ADP-ribose) polymerase (PARP) cleavage. FXY-1 treatment resulted in G 0/G 1 arrest in both cell lines at lower concentrations, but led to apoptosis at higher doses. Western blot analysis revealed dephosphorylation of Akt (Ser 473) with activation of p53, Bax, Bak, Bid and reduction in Bcl-2 and Bcl-xL levels. Further mechanistic investigation showed that FXY-1 activity was facilitated through an allosteric inhibition of Akt enzyme. FXY-1 treatment significantly reduced the tumor growth and pAkt levels in mouse xenograft exhibiting the in-vivo efficacy in the compound. Collectively, our results suggest DNA damage-mediated activation by FXY-1 in lung cancer cells leading to extensive apoptosis through the mitochondrial pathway.

Sestrin2 Protein Positively Regulates AKT Enzyme Signaling and Survival in Human Squamous Cell Carcinoma and Melanoma Cells

Skin cancer is the most common cancer in the United States and is mainly caused by environmental UV radiation. Reducing skin cancer incidence is becoming an urgent issue. The stress-inducible protein Sestrin2 (Sesn2) plays an important role in maintaining redox and metabolic homeostasis and their related pathologies. However, the role of Sesn2 in cancer remains unclear. Here we show that UVB radiation induces Sesn2 expression in normal human keratinocytes, mouse skin, normal human melanocytes, and melanoma cells. In addition, Sesn2 promotes AKT activation through a PTEN-dependent mechanism. Sesn2 deletion or knockdown sensitizes squamous cell carcinoma (SCC) cells to 5-fluorouracil-induced apoptosis and melanoma cells to UVB- and vemurafenib-induced apoptosis. In mice Sesn2 knockdown suppresses tumor growth from injected human SCC and melanoma cells. Last, as compared with normal skin, Sesn2 is up-regulated in both human skin SCC and melanoma. Our findings demonstrate that Sesn2 promotes AKT activation and survival in response to UVB stress and chemotherapeutics and suggest that Sesn2 is oncogenic in skin SCC and melanoma.

Activation of PI3K/Akt signaling in rostral ventrolateral medulla impairs brain stem cardiovascular regulation that underpins circulatory depression during mevinphos intoxication

As the most widely used pesticides in the globe, the organophosphate compounds are understandably linked with the highest incidence of suicidal poisoning. Whereas the elicited toxicity is often associated with circulatory depression, the underlying mechanisms require further delineation. Employing the pesticide mevinphos as our experimental tool, we evaluated the hypothesis that transcriptional upregulation of nitric oxide synthase II (NOS II) by NF-κB on activation of the PI3K/Akt cascade in the rostral ventrolateral medulla (RVLM), the brain stem site that maintains blood pressure and sympathetic vasomotor tone, underpins the circulatory depressive effects of organophosphate poisons. Microinjection of mevinphos (10nmol) bilaterally into the RVLM of anesthetized Sprague-Dawley rats induced a progressive hypotension that was accompanied sequentially by an increase (Phase I) and a decrease (Phase II) of an experimental index for the baroreflex-mediated sympathetic vasomotor tone. There were also progressive augmentations in PI3K or Akt enzyme activity and phosphorylation of p85 or Akt(Thr308) subunit in the RVLM that were causally related to an increase in NF-κB transcription activity and elevation in NOS II or peroxynitrite expression. Loss-of-function manipulations of PI3K or Akt in the RVLM significantly antagonized the reduced baroreflex-mediated sympathetic vasomotor tone and hypotension during Phase II mevinphos intoxication, and blunted the increase in NF-κB/NOS II/peroxynitrite signaling. We conclude that activation of the PI3K/Akt cascade, leading to upregulation of NF-κB/NOS II/peroxynitrite signaling in the RVLM, elicits impairment of brain stem cardiovascular regulation that underpins circulatory depression during mevinphos intoxication.

Discovery and SAR of spirochromane Akt inhibitors

A novel series of spirochromane pan-Akt inhibitors is reported. SAR optimization furnished compounds with improved enzyme potencies and excellent selectivity over the related AGC kinase PKA. Attempted replacement of the phenol hinge binder provided compounds with excellent Akt enzyme and cell activities but greatly diminished selectivity over PKA.

Compensatory effects in the PI3K/PTEN/AKT signaling network following receptor tyrosine kinase inhibition

Overcoming de novo and acquired resistance to anticancer drugs that target signaling networks is a formidable challenge for drug design and effective cancer therapy. Understanding the mechanisms by which this resistance arises may offer a route to addressing the insensitivity of signaling networks to drug intervention and restore the efficacy of anticancer therapy. Extending our recent work identifying PTEN as a key regulator of Herceptin sensitivity, we present an integrated theoretical and experimental approach to study the compensatory mechanisms within the PI3K/PTEN/AKT signaling network that afford resistance to receptor tyrosine kinase (RTK) inhibition by anti-HER2 monoclonal antibodies. In a computational model representing the dynamics of the signaling network, we define a single control parameter that encapsulates the balance of activities of the enzymes involved in the PI3K/PTEN/AKT cycle. By varying this control parameter we are able to demonstrate both distinct dynamic regimes of behavior of the signaling network and the transitions between those regimes. We demonstrate resistance, sensitivity, and suppression of RTK signals by the signaling network. Through model analysis we link the sensitivity-to-resistance transition to specific compensatory mechanisms within the signaling network. We study this transition in detail theoretically by variation of activities of PTEN, PI3K, AKT enzymes, and use the results to inform experiments that perturb the signaling network using combinatorial inhibition of RTK, PTEN, and PI3K enzymes in human ovarian carcinoma cell lines. We find good alignment between theoretical predictions and experimental results. We discuss the application of the results to the challenges of hypersensitivity of the signaling network to RTK signals, suppression of drug resistance, and efficacy of drug combinations in anticancer therapy.

Inhibition of Akt signaling in hepatoma cells induces apoptotic cell death independent of Akt activation status

The serine/threonine kinase Akt, a downstream effector of phosphatidylinositol 3-kinase (PI3K), is involved in cell survival and anti-apoptotic signaling. Akt has been shown to be constitutively expressed in a variety of human tumors including hepatocellular carcinoma (HCC). In this report we analyzed the status of Akt pathway in three HCC cell lines, and tested cytotoxic effects of Akt pathway inhibitors LY294002, Wortmannin and Inhibitor VIII. In Mahlavu human hepatoma cells Akt was constitutively activated, as demonstrated by its Ser473 phosphorylation, downstream hyperphosphorylation of BAD on Ser136, and by a specific cell-free kinase assay. In contrast, Huh7 and HepG2 did not show hyperactivation when tested by the same criteria. Akt enzyme hyperactivation in Mahlavu was associated with a loss of PTEN protein expression. Akt signaling was inhibited by the upstream kinase inhibitors, LY294002, Wortmannin, as well as by the specific Akt Inhibitor VIII in all three hepatoma cell lines. Cytotoxicity assays with Akt inhibitors in the same cell lines indicated that they were all sensitive, but with different IC50 values as assayed by RT-CES. We also demonstrated that the cytotoxic effect was through apoptotic cell death. Our findings provide evidence for its constitutive activation in one HCC cell line, and that HCC cell lines, independent of their Akt activation status respond to Akt inhibitors by apoptotic cell death. Thus, Akt inhibition may be considered as an attractive therapeutic intervention in liver cancer.

Akt enzyme: new therapeutic target in cancer and diabetes?

Alteration of apoptotic processes plays a central role in the development and progression of several chronic disorders. Proteins responsible for the regulation of apoptosis are therapeutic targets; these include the Akt enzyme. Akt enzyme is expressed in most cell types. Akt activation is regulated by growth factors, insulin, and also environmental factors as altered oxygen tension and high temperature. Akt is a central regulator of cellular metabolism and survival. Akt function is reportedly altered in some disorders. An increased activity of Akt has been described in prostate, breast, colon, and pancreatic cancer, as well as in hematological malignancies. Akt is also a factor in the pathomechanism of diabetes as it determines beta-cell apoptosis of Langerhans islets and insulin sensitivity of the cells. Several studies revealed that some of the marketed drugs including statins, thiazolidinediones and ACE inhibitors modulate Akt activity. There are efforts to develop specific Akt inhibitors that may improve the efficacy of chemotherapy. Triciribine and perifosine are two Akt inhibitors in developmental phase 1 and 2 that may improve survival in breast cancer, pancreas cancer, gastrointestinal stroma tumor, sarcoma and melanoma, and in hematological malignancy.