Displaying publications 41 - 60 of 112 in total

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  1. 14-Deoxy-11,12-didehydroandrographolide induces DDIT3-dependent endoplasmic reticulum stress-mediated autophagy in T-47D breast carcinoma cells
    Tan HK, Muhammad TST, Tan ML
    Toxicol Appl Pharmacol, 2016 06 01;300:55-69.
    PMID: 27049118 DOI: 10.1016/j.taap.2016.03.017
    14-Deoxy-11,12-didehydroandrographolide (14-DDA), a major diterpenoid isolated from Andrographis paniculata (Burm.f.) Nees, is known to be cytotoxic and elicits a non-apoptotic cell death in T-47D breast carcinoma cells. In this study, the mechanistic toxicology properties of 14-DDA in T-47D cells were further investigated. 14-DDA is found to induce the formation of endoplasmic reticulum (ER) vacuoles and autophagosomes, with concurrent upregulation of LC3-II in the breast carcinoma cells. It stimulated an increase in cytosolic calcium concentration and caused a collapse in mitochondrial membrane potential in these cells. In addition, both DDIT3 and GADD45A, molecules implicated in ER stress pathway, were significantly upregulated. DDIT3 knockdown suppressed the formation of both ER vacuoles and autophagosomes, indicating that 14-DDA-induced ER stress and autophagy is dependent on this transcription factor. Collectively, it is possible that GADD45A/p38 MAPK/DDIT3 pathway is involved in the 14-DDA-induced ER-stress-mediated autophagy in T-47D cells.
    Matched MeSH terms: Proto-Oncogene Proteins c-akt/metabolism
  2. Fulltext Fibroblast growth factor receptor 4 (FGFR4) and fibroblast growth factor 19 (FGF19) autocrine enhance breast cancer cells survival
    Tiong KH, Tan BS, Choo HL, Chung FF, Hii LW, Tan SH, et al.
    Oncotarget, 2016 Sep 06;7(36):57633-57650.
    PMID: 27192118 DOI: 10.18632/oncotarget.9328
    Basal-like breast cancer is an aggressive tumor subtype with poor prognosis. The discovery of underlying mechanisms mediating tumor cell survival, and the development of novel agents to target these pathways, is a priority for patients with basal-like breast cancer. From a functional screen to identify key drivers of basal-like breast cancer cell growth, we identified fibroblast growth factor receptor 4 (FGFR4) as a potential mediator of cell survival. We found that FGFR4 mediates cancer cell survival predominantly via activation of PI3K/AKT. Importantly, a subset of basal-like breast cancer cells also secrete fibroblast growth factor 19 (FGF19), a canonical ligand specific for FGFR4. siRNA-mediated silencing of FGF19 or neutralization of extracellular FGF19 by anti-FGF19 antibody (1A6) decreases AKT phosphorylation, suppresses cancer cell growth and enhances doxorubicin sensitivity only in the FGFR4+/FGF19+ breast cancer cells. Consistently, FGFR4/FGF19 co-expression was also observed in 82 out of 287 (28.6%) primary breast tumors, and their expression is strongly associated with AKT phosphorylation, Ki-67 staining, higher tumor stage and basal-like phenotype. In summary, our results demonstrated the presence of an FGFR4/FGF19 autocrine signaling that mediates the survival of a subset of basal-like breast cancer cells and suggest that inactivation of this autocrine loop may potentially serve as a novel therapeutic intervention for future treatment of breast cancers.
    Matched MeSH terms: Proto-Oncogene Proteins c-akt/metabolism
  3. Bisleuconothine A Induces Autophagosome Formation by Interfering with AKT-mTOR Signaling Pathway
    Wong CP, Seki A, Horiguchi K, Shoji T, Arai T, Nugroho AE, et al.
    J Nat Prod, 2015 Jul 24;78(7):1656-62.
    PMID: 26176165 DOI: 10.1021/acs.jnatprod.5b00258
    We have previously reported that bisleuconothine A (Bis-A), a novel bisindole alkaloid isolated from Leuconotis griffithii, showed cytostatic activity in several cell lines. In this report, the mechanism of Bis-A-induced cytostatic activity was investigated in detail using A549 cells. Bis-A did not cause apoptosis, as indicated by analysis of annexin V and propidium iodide staining. Expression of all tested apoptosis-related proteins was also unaffected by Bis-A treatment. Bis-A was found to increase LC3 lipidation in MCF7 cells as well as A549 cells, suggesting that Bis-A cytostatic activity may be due to induction of autophagy. Subsequent investigation via Western blotting and immunofluorescence staining indicated that Bis-A induced formation but prevented degradation of autophagosomes. Mechanistic studies showed that Bis-A down-regulated phosphorylation of protein kinase B (AKT) and its downstream kinase, PRAS40, which is an mTOR repressor. Moreover, phosphorylation of p70S6K, an mTOR-dependent kinase, was also down-regulated. Down-regulation of these kinases suggests that the increase in LC3 lipidation may be due to mTOR deactivation. Thus, the cytostatic activity shown by Bis-A may be attributed to its induction of autophagosome formation. The Bis-A-induced autophagosome formation was suggested to be caused by its interference with the AKT-mTOR signaling pathway.
    Matched MeSH terms: Proto-Oncogene Proteins c-akt/metabolism
  4. Fulltext Current therapies and targets for type 2 diabetes mellitus
    Chellappan DK, Yap WS, Bt Ahmad Suhaimi NA, Gupta G, Dua K
    Panminerva Med, 2018 Sep;60(3):117-131.
    PMID: 29696964 DOI: 10.23736/S0031-0808.18.03455-9
    The prevalence of type 2 diabetes mellitus (T2DM) has been increasing at an alarming rate. With an increased understanding of the pathophysiology and pathogenesis of T2DM, various new therapeutic options have been developed to target different key defects in T2DM. Incremental innovations of existing therapies either through unprecedented drug combinations, modified drug molecules, or improved delivery systems are capable to nullify some of the undesirable side effects of traditional therapies as well as to enhance effectiveness. The existing administration routes include inhalation, nasal, buccal, parenteral and oral. Newer drug targets such as protein kinase B (Akt/PKB), AMP-activated protein kinase (AMPK), sirtuin (SIRT), and others are novel approaches that act via different mechanisms and possibly treating T2DM of distinct variations and aetiologies. Other therapies such as endobarrier, gene therapy, and stem cell technology utilize advanced techniques to treat T2DM, and the potential of these therapies are still being explored. Gene therapy is plausible to fix the underlying pathology of T2DM instead of using traditional reactive treatments, especially with the debut of Clustered Regularly Interspaced Short Palindromic Repeats-CRISPR associated protein9 (CRISPR-Cas9) gene editing tool. Molecular targets in T2DM are also being extensively studied as it could target the defects at the molecular level. Furthermore, antibody therapies and vaccinations are also being developed against T2DM; but the ongoing clinical trials are relatively lesser and the developmental progress is slower. Although, there are many therapies designed to cure T2DM, each of them has their own advantages and disadvantages. The preference for the treatment plan usually depends on the health status of the patient and the treatment goal. Therefore, an ideal treatment should take patient's compliance, efficacy, potency, bioavailability, and other pharmacological and non-pharmacological properties into account.
    Matched MeSH terms: Proto-Oncogene Proteins c-akt/metabolism
  5. Improvement of mitochondrial function by celastrol in palmitate-treated C2C12 myotubes via activation of PI3K-Akt signaling pathway
    Abu Bakar MH, Tan JS
    Biomed Pharmacother, 2017 Sep;93:903-912.
    PMID: 28715871 DOI: 10.1016/j.biopha.2017.07.021
    Compelling evidences posited that high level of saturated fatty acid gives rise to mitochondrial dysfunction and inflammation in the development of insulin resistance in skeletal muscle. Celastrol is a pentacyclic triterpenoid derived from the root extracts of Tripterygium wilfordii that possesses potent anti-inflammatory properties in a number of animal models with metabolic diseases. However, the cellular mechanistic action of celastrol in alleviating obesity-induced insulin resistance in skeletal muscle remains largely unknown. Therefore, the present investigation evaluated the attributive properties of celastrol at different concentrations (10, 20, 30 and 40nM) on insulin resistance in C2C12 myotubes evoked by palmitate. We demonstrated that celastrol improved mitochondrial functions through significant enhancement of intracellular ATP content, mitochondrial membrane potential, citrate synthase activity and decrease of mitochondrial superoxide productions. Meanwhile, augmented mitochondrial DNA (mtDNA) content with suppressed DNA oxidative damage were observed following celastrol treatment. Celastrol significantly enhanced fatty acid oxidation rate and increased the level of tricarboxylic acid (TCA) cycle intermediates in palmitate-treated cells. Further analysis revealed that the improvement of glucose uptake activity in palmitate-loaded myotubes was partly mediated by celastrol via activation of PI3K-Akt insulin signaling pathway. Collectively, these findings provided evidence for the first time that the protection from palmitate-mediated insulin resistance in C2C12 myotubes by celastrol is likely associated with the improvement of mitochondrial functions-related metabolic activities.
    Matched MeSH terms: Proto-Oncogene Proteins c-akt/metabolism*
  6. Activation of phosphatidylinositol 3-kinase/Akt signaling by EGF downregulates membranous E-cadherin and β-catenin and enhances invasion in nasopharyngeal carcinoma cells
    Yip WK, Seow HF
    Cancer Lett, 2012 May 28;318(2):162-72.
    PMID: 22182447 DOI: 10.1016/j.canlet.2011.12.018
    Dysregulation of E-cadherin and β-catenin function in cell-cell adhesion is common in nasopharyngeal carcinoma (NPC) and correlates with metastatic disease. In this study, we examined the role of EGF-activated phosphatidylinositol 3-kinase (PI3K)-Akt signaling in E-cadherin and β-catenin regulation. We found that reduced membranous E-cadherin and β-catenin expression was positively correlated with Akt phosphorylation in NPC tissues. EGF treatment disrupted cell-cell adhesion and resulted in mesenchymal morphological features in NPC cell lines (TW01, TW04, and TW06). Western blot analysis showed that the E-cadherin protein level was partially reduced in TW04 cells only and the β-catenin levels were not considerably affected upon EGF treatment. In contrast, quantitative real-time RT-PCR showed that the E-cadherin, but not β-catenin, mRNA levels were markedly reduced by EGF in all cell lines. Immunofluorescent staining revealed that E-cadherin and β-catenin appeared to be markedly reduced on the cell surface and more localized in the cytoplasm. Inhibition of PI3K by LY294002 did not abolish the EGF-induced downregulation of E-cadherin protein or mRNA in TW04 cells but moderately increased the β-catenin protein level in TW01 cells and mRNA level in TW06 cells. However, LY294002 substantially restored or increased cell surface E-cadherin and β-catenin in all EGF-treated cell lines, in concordance with the inhibition of cell morphological changes. Moreover, LY294002 significantly blocked EGF-driven cell invasion, correlating with the elevation of membranous E-cadherin and β-catenin levels. In conclusion, EGF-induced epithelial-to-mesenchymal transition may not be only dependent on downregulation of E-cadherin protein/mRNA but also on mislocalization of E-cadherin and β-catenin. The mechanisms involved may be related, at least in part, to the PI3K-Akt pathway.
    Matched MeSH terms: Proto-Oncogene Proteins c-akt/metabolism*
  7. Zerumbone suppresses the activation of inflammatory mediators in LPS-stimulated U937 macrophages through MyD88-dependent NF-κB/MAPK/PI3K-Akt signaling pathways
    Haque MA, Jantan I, Harikrishnan H
    Int Immunopharmacol, 2018 Feb;55:312-322.
    PMID: 29310107 DOI: 10.1016/j.intimp.2018.01.001
    Zerumbone (ZER), isolated mainly from the Zingiber zerumbet (Z. zerumbet) rhizomes was found to be effective against numerous inflammatory and immune disorders, however, the molecular and biochemical mechanisms underlying its anti-inflammatory and immunosuppressive properties have not been well studied. This study was carried out to examine the profound effects of ZER on inflammatory mediated MyD88-dependent NF-κB/MAPK/PI3K-Akt signaling pathways in LPS-stimulated U937 human macrophages. ZER significantly suppressed the up-regulation pro-inflammatory mediators, TNF-α, IL-1β, PGE2, and COX-2 protein in LPS-induced human macrophages. Moreover, ZER significantly downregulated the phosphorylation of NF-κB (p65), IκBα, and IKKα/β as well as restored the degradation of IκBα. ZER correspondingly showed remarkable attenuation of the expression of Akt, JNK, ERK, and p38 MAPKs phosphorylation in a concentration-dependent manner. ZER also diminished the expression of upstream signaling molecules TLR4 and MyD88, which are prerequisite for the NF-κB, MAPK and PI3K-Akt activation. Additionally, quantification of relative gene expression of TNF-α, IL-1β, and COX-2 indicated that, at a higher dose (50μM), ZER significantly downregulated the elevated mRNA transcription levels of the stated pro-inflammatory markers in LPS-stimulated U937 macrophages. The strong suppressive effects of ZER on the activation of inflammatory markers in the macrophages via MyD88-dependent NF-κB/MAPK/PI3K-Akt signaling pathways suggest that ZER can be a preventive and potent therapeutic candidate for the management of various inflammatory-mediated immune disorders.
    Matched MeSH terms: Proto-Oncogene Proteins c-akt/metabolism
  8. LY294002, a PI3K pathway inhibitor, prevents leptin-induced adverse effects on spermatozoa in Sprague-Dawley rats
    Md Mokhtar AH, Malik IA, Abd Aziz NAA, Almabhouh FA, Durairajanayagam D, Singh HJ
    Andrologia, 2019 Apr;51(3):e13196.
    PMID: 30456785 DOI: 10.1111/and.13196
    This study examined the effects of PI3K and AMPK signalling pathway inhibitors on leptin-induced adverse effects on rat spermatozoa. Sprague-Dawley rats, aged 14-16 weeks, were randomised into control, leptin-, leptin + dorsomorphin (AMPK inhibitor)-, and leptin+LY294002 (PI3K inhibitor)-treated groups with six rats per group. Leptin was given once daily for 14 days via the intraperitoneal (i.p.) route at a dose of 60 ug kg-1 body weight. Rats in the leptin and inhibitor-treated groups received concurrently either dorsomorphin (5 mg kg-1  day-1 ) or LY294002 (1.2 mg kg-1  day-1 ) i.p. for 14 days. Controls received 0.1 ml of normal saline. Upon completion, sperm count, sperm morphology, seminiferous tubular epithelial height (STEH), seminiferous tubular diameter (STD), 8-hydroxy-2-deoxyguanosine (8-OHdG) and phospho-Akt/total Akt ratio were estimated. Data were analysed using ANOVA. Sperm count, STEH and STD were significantly lower, while the percentage of spermatozoa with abnormal morphology and the level of 8-OHdG were significantly higher in rats treated with leptin and leptin + dorsomorphin when compared to those in controls and LY294002-treated rats. Testicular phospho-Akt/total Akt ratio was significantly higher in leptin and leptin + LY294002-treated rats. In conclusion, LY294002 prevents leptin-induced changes in rat sperm parameters, suggesting the potential role of the PI3K signalling pathway in the adverse effects of leptin on sperm parameters.
    Matched MeSH terms: Proto-Oncogene Proteins c-akt/metabolism
  9. Caralluma pauciflorabased Ag-NPs activate ROS - induced apoptosis through down-regulation of AKT, mTOR and pI3K signaling in human gastric cancer (AGS) cells
    Navaneethan RD, N C J PL, Ramaiah M, Ravindran R, T AK, Chinnathambi A, et al.
    Nanotechnology, 2024 Feb 21;35(19).
    PMID: 38320329 DOI: 10.1088/1361-6528/ad26d9
    The phytochemicals found inCaralluma pauciflorawere studied for their ability to reduce silver nitrate in order to synthesise silver nanoparticles (AgNPs) and characterise their size and crystal structure. Thunbergol, 1,1,6-trimethyl-3-methylene-2-(3,6,9,13-tetram, Methyl nonadecanoate, Methyl cis-13,16-Docosadienate, and (1R,4aR,5S)-5-[(E)-5-Hydroxy-3-methylpent were the major compounds identified in the methanol extract by gas chromatography-mass spectrum analysis. UV/Vis spectra, Fourier-transform infrared spectroscopy, x-ray diffraction, scanning electron microscope with Energy Dispersive Xâray Analysis (EDAX), Dynamic Light Scattering (DLS) particle size analyser and atomic force microscope (AfM) were used to characterise theCaralluma paucifloraplant extract-based AgNPs. The crystal structure and estimated size of the AgNPs ranged from 20.2 to 43 nm, according to the characterization data. The anti-cancer activity of silver nanoparticles (AgNPs) synthesised fromCaralluma paucifloraextract. The AgNPs inhibited more than 60% of the AGS cell lines and had an IC50 value of 10.9640.318 g, according to the findings. The cells were further examined using fluorescence microscopy, which revealed that the AgNPs triggered apoptosis in the cells. Furthermore, the researchers looked at the levels of reactive oxygen species (ROS) in cells treated with AgNPs and discovered that the existence of ROS was indicated by green fluorescence. Finally, apoptotic gene mRNA expression analysis revealed that three target proteins (AKT, mTOR, and pI3K) were downregulated following AgNP therapy. Overall, the findings imply that AgNPs synthesised from Caralluma pauciflora extract could be used to treat human gastric cancer.
    Matched MeSH terms: Proto-Oncogene Proteins c-akt/metabolism
  10. Fulltext Targeting extracellular matrix remodeling in disease: Could resveratrol be a potential candidate?
    Agarwal R, Agarwal P
    Exp Biol Med (Maywood), 2017 Feb;242(4):374-383.
    PMID: 27798117 DOI: 10.1177/1535370216675065
    Disturbances of extracellular matrix homeostasis are associated with a number of pathological conditions. The ability of extracellular matrix to provide contextual information and hence control the individual or collective cellular behavior is increasingly being recognized. Hence, newer therapeutic approaches targeting extracellular matrix remodeling are widely investigated. We reviewed the current literature showing the effects of resveratrol on various aspects of extracellular matrix remodeling. This review presents a summary of the effects of resveratrol on extracellular matrix deposition and breakdown. Mechanisms of action of resveratrol in extracellular matrix deposition involving growth factors and their signaling pathways are discussed. Involvement of phosphoinositol-3-kinase/Akt and mitogen-activated protein kinase pathways and role of transcription factors and sirtuins on the effects of resveratrol on extracellular matrix homeostasis are summarized. It is evident from the literature presented in this review that resveratrol has significant effects on both the synthesis and breakdown of extracellular matrix. The major molecular targets of the action of resveratrol are growth factors and their signaling pathways, phosphoinositol-3-kinase/Akt and mitogen-activated protein kinase pathways, transcription factors, and SIRT-1. The effects of resveratrol on extracellular matrix and the molecular targets appear to be related to experimental models, experimental environment as well as the doses.
    Matched MeSH terms: Proto-Oncogene Proteins c-akt/metabolism*
  11. Syringin from Tinospora crispa downregulates pro-inflammatory mediator production through MyD88-dependent pathways in lipopolysaccharide (LPS)-induced U937 macrophages
    Arshad L, Haque MA, Harikrishnan H, Ibrahim S, Jantan I
    Mol Biol Rep, 2024 Jul 11;51(1):789.
    PMID: 38990383 DOI: 10.1007/s11033-024-09722-z
    BACKGROUND: Syringin, a phenylpropanoid glycoside, has exhibited numerous biological properties including inhibitory activities against various immune and inflammatory disorders. In this study, syringin isolated from Tinospora crispa was evaluated for its ability to down-regulate activated nuclear factor-kappa B (NF-κB), phosphoinositide-3-kinase-Akt (PI3K-Akt) and mitogen-activated protein kinases (MAPKs) signal transducing networks in U937 macrophages activated by lipopolysaccharide.

    METHODS: The attenuating effects of syringin on the productions of prostaglandin E2 (PGE2), cyclooxygenase-2 (COX-2), interleukin-1β (IL-1β), and tumor necrosis factor-α (TNF-α), and the expressions of signaling molecules of the signaling pathways were investigated by using ELISA, Western blot, and qRT-PCR.

    RESULTS: Syringin downregulated the NF-κB, MAPKs, and PI3K-Akt signal networks by significantly reducing PGE2 production in the macrophages via suppression of COX-2 gene and protein expression levels. It also reduced TNF-α and IL-1β secretion and their mRNA expression, suppressed phosphorylation of NF-κB (p65), IKKα/β, and IκBα, and restored ability of IκBα to degrade. Syringin dose-dependently attenuated Akt, p38 MAPKs, JNK, and ERK phosphorylation. Also, the expression of corresponding upstream signaling molecules toll-like receptor 4 (TLR4) and myeloid differentiation primary response gene 88 (MyD88) were down-regulated in response to syringin treatment.

    CONCLUSION: The suppressive effect of syringin on the inflammatory signaling molecules in MyD88-dependent pathways suggested it's potential as a drug candidate for development into an agent for treatment of various immune-mediated inflammatory disorders.

    Matched MeSH terms: Proto-Oncogene Proteins c-akt/metabolism
  12. Fulltext Expression of fibroblast growth factor receptor 4 (FGFR-4) in nasopharyngeal carcinoma (NPC) cell lines and its potential as therapeutic target
    Hooi Yeen Yap, Jack Bee Chook, Sin Yeang Teow
    Malaysian Journal of Medicine and Health Sciences, 2019;15(108):49-49.
    MyJurnal
    ntroduction: Nasopharyngeal carcinoma (NPC) is a prevalent cancer among human population in Southern China, Hong Kong and Southeast Asia. In Malaysia, NPC is the fourth most common cancer in both sexes, predominantly in the Chinese. Epstein-Barr virus (EBV) infection is known to be highly associated with NPC. Fibroblast growth factor receptor-4 (FGFR4) is part of the family of tyrosine kinase receptors that regulate cell survival, differentiation and pro-liferation. The binding of FGFR4 ligands such as fibroblasts growth factors (FGFs) has been shown to activate various oncogenic signalling pathway including MAPK, Ras and PI3K-Akt pathways. In the past, FGFR4 has been shown to promote tumorigenesis and tumour progression in various cancers such as liver, colon, breast and pancreatic and gastric cancers. However, its role in NPC establishment and pathogenesis is under-explored. This study aimed to evaluate the FGFR4 expression in NPC using various cell lines and its potential as a therapeutic target for NPC treat-ment by gene silencing. Methods: The basal FGFR4 level of NPC (EBV-positive: C666-1 and EBV-negative: HONE1 and HK1) and nasopharyngeal epithelial (NPE) normal (NP69 and NP460) cell lines was determined by western blot analysis and RT-qPCR. FGFR4 level at different time points (0, 24, 48, and 72 hours) in HONE1 and C666-1 cell lines were determined by western blot analysis. Luminescence-based assay was performed to determine the cell prolifer-ation of NPC cells in correlation with the FGFR4 expression. NPC cells were then treated with the optimised FGFR4 siRNA or FGFR inhibitor, BLU-9931 and the silencing/ inhibition of FGFR4 expression was confirmed by western blot analysis. The effect of FGFR4 inhibition on the cell proliferation and aggressiveness of NPC cells was then investigat-ed through wound healing assay and invasion marker analysis. Results: Out of the five tested cell lines, HONE1 and C666-1 highly expressed FGFR4, NP69 showed very low expression while HK1 and NP460 did not express FGFR4. In the time-point study, the FGFR4 level of HONE1 and C666-1 peaked at 24-48 hours which is the exponential phase of cells. Following that, the FGFR4 level decreased corresponding to the decreased cell growth rate due to the nutrient deprivation. siRNA experiments showed that 6.25nM of four siRNAs (5, 6, 9 and 10) could effectively target and silence the FGFR4 expression of HONE1, but not in C666-1 even up to 250nM was tested. When BLU-9931 was used, only modest inhibition was observed in both cells at 3uM. Compared to the untreated control, FGFR4-inhibited HONE1 exhibited decreased cell proliferation rate. Cell migration and invasion capabilities of HONE1 were also significantly reduced following the FGFR4 silencing, suggesting the potential of utilising FGFR4 as the therapeutic target. Conclusion: FGFR4 is highly expressed in C666-1 (EBV-positive) and HONE1 (initially EBV-positive, but lost EBV genome in subsequent in vitro passage) NPC cells, but not in EBV-negative HK1 NPC cell and normal NPE cells. FGFR4 gene silencing effectively inhibited the cell proliferation, migration and invasive potentials of NPC cell line. These findings highlight the therapeutic value of targeting FGFR4 for NPC treatment. Further investigations are war-ranted to reveal the molecular mechanism and the possible role of EBV in regulating FGFR4 pathway.
    Matched MeSH terms: Proto-Oncogene Proteins c-akt
  13. Fulltext Estrogen Receptors in Nonfunctioning Pituitary Neuroendocrine Tumors: Review on Expression and Gonadotroph Functions
    Haydar Ali Tajuddin A, Kamaruddin N, Sukor N, Azizan EA, Omar AM
    J Endocr Soc, 2020 Dec 01;4(12):bvaa157.
    PMID: 33241169 DOI: 10.1210/jendso/bvaa157
    Estrogen (17β-estradiol or E2) is a crucial regulator of the synthesis and secretion of pituitary reproductive hormones luteinizing hormone, follicle-stimulating hormone, and prolactin. In this review, we summarize the role of estrogen receptors in nonfunctioning pituitary neuroendocrine tumors (NF-Pitnets), focusing on immunoexpression and gonadotroph cell proliferation and apoptosis. Gonadotroph tumors are the most common subtype of NF-Pitnets. Two major estrogen receptor (ER) isoforms expressed in the pituitary are estrogen receptor alpha (ERα) and estrogen receptor beta (ERβ). Overall, estrogen actions are mostly exerted through the ERα isoform on the pituitary. The G protein-coupled estrogen receptor (GPER) located at the plasma membrane may contribute to nongenomic effects of estrogen. Nuclear immunoreactivity for ERα and ERβ was highest among gonadotroph and null cell tumors. Silent corticotroph tumors are the least immunoreactive for both receptors. A significantly elevated ERα expression was observed in macroadenomas compared with microadenomas. ERα and ERβ may act in opposite directions to regulate the Slug-E-cadherin pathway and to affect invasiveness of NF-Pitnets. In the cellular pathway, ERs regulate estrogen-induced proliferation and differentiation and impact several signaling pathways including the MAPK and PI3K/Akt pathway. Estrogen was the first-discovered inducer of pituitary tumor transforming gene 1 that was abundantly expressed in NF-Pitnets. ERα can be a potential biomarker for predicting tumor size and invasiveness as well as therapeutic target for NF-Pitnets. Selective estrogen receptor modulators or antiestrogen may represent as an alternative choice for the treatment of NF-Pitnets.
    Matched MeSH terms: Proto-Oncogene Proteins c-akt
  14. Fulltext Induction of apoptosis and role of paclitaxel-loaded hyaluronic acid-crosslinked nanoparticles in the regulation of AKT and RhoA
    Chaudhry GE, Akim A, Zafar MN, Abdullah MA, Sung YY, Muhammad TST
    J Adv Pharm Technol Res, 2020 07 14;11(3):101-106.
    PMID: 33102192 DOI: 10.4103/japtr.JAPTR_26_20
    Cancer is a complex multifactorial disease and leading causes of death worldwide. Despite the development of many anticancer drugs, there is a reduced survival rate due to severe side effects. The nontargeted approach of convention drugs is one of the leading players in context to toxicity. Hyaluronan is a versatile bio-polymer and ligand of the receptor (CD44) on cancer cells. The MCF-7 and HT-29 cancer cell lines treated with hyaluronic acid-paclitaxel (HA-PTX) showed the distinguishing morphological features of apoptosis. Flow cytometric analysis showed that HA-PTX induces apoptosis as a significant mode of cell death. The activation level of tumor suppressor protein (p53) increased after PTX treatment in MCF-7, but no changes observed in HT-29 might be due to hereditary mutations. The lack of suppression in AKT and Rho A protein suggest the use of possible inhibitors in future studies which might could play a role in increasing the sensitivity of drug towards mutated cells line and reducing the possibilities for cancer cell survival, migration, and metastasis.
    Matched MeSH terms: Proto-Oncogene Proteins c-akt
  15. Fulltext Intracellular Delivery of siRNAs Targeting AKT and ERBB2 Genes Enhances Chemosensitization of Breast Cancer Cells in a Culture and Animal Model
    Fatemian T, Moghimi HR, Chowdhury EH
    Pharmaceutics, 2019 Sep 03;11(9).
    PMID: 31484456 DOI: 10.3390/pharmaceutics11090458
    : Pharmacotherapy as the mainstay in the management of breast cancer suffers from various drawbacks, including non-targeted biodistribution, narrow therapeutic and safety windows, and also resistance to treatment. Thus, alleviation of the constraints from the pharmacodynamic and pharmacokinetic profile of classical anti-cancer drugs could lead to improvements in efficacy and patient survival in malignancies. Moreover, modifications in the genetic pathophysiology of cancer via administration of small nucleic acids might pave the way towards higher response rates to chemotherapeutics. Inorganic pH-dependent carbonate apatite (CA) nanoparticles were utilized in this study to efficiently deliver various classes of therapeutics into cancer cells. Co-delivery of drugs and genetic materials was successfully attained through a carbonate apatite delivery device. On 4T1 cells, siRNAs against AKT and ERBB2 plus paclitaxel or docetaxel resulted in the largest increase in anti-cancer effects compared to CA/paclitaxel or CA/docetaxel. Therefore, these ingredients were selected for further in vivo investigations. Animals receiving injections of CA/paclitaxel or CA/docetaxel loaded with siRNAs against AKT and ERBB2 possessed significantly smaller tumors compared to CA/drug-treated mice. Interestingly, synergistic interactions in target protein knock down with combinations of CA/AKT/paclitaxel, CA/ERBB2/docetaxel were documented via western blotting.
    Matched MeSH terms: Proto-Oncogene Proteins c-akt
  16. Fulltext Maternal Cognitive Impairment Associated with Gestational Diabetes Mellitus-A Review of Potential Contributing Mechanisms
    John CM, Mohamed Yusof NIS, Abdul Aziz SH, Mohd Fauzi F
    Int J Mol Sci, 2018 Dec 05;19(12).
    PMID: 30563117 DOI: 10.3390/ijms19123894
    Gestational diabetes mellitus (GDM) carries many risks, where high blood pressure, preeclampsia and future type II diabetes are widely acknowledged, but less focus has been placed on its effect on cognitive function. Although the multifactorial pathogenesis of maternal cognitive impairment is not completely understood, it shares several features with type 2 diabetes mellitus (T2DM). In this review, we discuss some key pathophysiologies of GDM that may lead to cognitive impairment, specifically hyperglycemia, insulin resistance, oxidative stress, and neuroinflammation. We explain how these incidents: (i) impair the insulin-signaling pathway and/or (ii) lead to cognitive impairment through hyperphosphorylation of τ protein, overexpression of amyloid-β and/or activation of microglia. The aforementioned pathologies impair the insulin-signaling pathway primarily through serine phosphorylation of insulin receptor substances (IRS). This then leads to the inactivation of the phosphatidylinositol 3-kinase/Protein kinase B (PI3K/AKT) signaling cascade, which is responsible for maintaining brain homeostasis and normal cognitive functioning. PI3K/AKT is crucial in maintaining normal cognitive function through the inactivation of glycogen synthase kinase 3β (GSκ3β), which hyperphosphorylates τ protein and releases pro-inflammatory cytokines that are neurotoxic. Several biomarkers were also highlighted as potential biomarkers of GDM-related cognitive impairment such as AGEs, serine-phosphorylated IRS-1 and inflammatory markers such as tumor necrosis factor α (TNF-α), high-sensitivity C-reactive protein (hs-CRP), leptin, interleukin 1β (IL-1β), and IL-6. Although GDM is a transient disease, its complications may be long-term, and hence increased mechanistic knowledge of the molecular changes contributing to cognitive impairment may provide important clues for interventional strategies.
    Matched MeSH terms: Proto-Oncogene Proteins c-akt
  17. Fulltext Safrana l Prevents Prostate Cancer Recurrence by Blocking the Re-activation of Quiescent Cancer Cells via Downregulation of S-Phase Kinase-Associated Protein 2
    Jiang X, Li Y, Feng JL, Nik Nabil WN, Wu R, Lu Y, et al.
    Front Cell Dev Biol, 2020;8:598620.
    PMID: 33392189 DOI: 10.3389/fcell.2020.598620
    The re-proliferation of quiescent cancer cells is considered to be the primary contributor to prostate cancer (Pca) recurrence and progression. In this study, we investigated the inhibitory effect of safranal, a monoterpene aldehyde isolated from Crocus sativus (saffron), on the re-proliferation of quiescent Pca cells in vitro and in vivo. The results showed that safranal efficiently blocked the re-activation of quiescent Pca cells by downregulating the G0/G1 cell cycle regulatory proteins CDK2, CDK4, CDK6, and phospho-Rb at Ser807/811 and elevating the levels of cyclin-dependent kinase inhibitors, p21 and p27. Further investigation on the underlying mechanisms revealed that safranal suppressed the mRNA and protein expression levels of Skp2, possibly through the deregulation of the transcriptional activity of two major transcriptional factors, E2F1 and NF-κB subunits. Moreover, safranal inhibited AKT phosphorylation at Ser473 and deregulated both canonical and non-canonical NF-κB signaling pathways. Safranal suppressed the tumor growth of quiescent Pca cell xenografts in vivo. Furthermore, safranal-treated tumor tissues exhibited a reduction in Skp2, E2F1, NF-κB p65, p-IκBα (Ser32), c-MYC, p-Rb (Ser807), CDK4, CDK6, and CDK2 and an elevation of p27 and p21 protein levels. Therefore, our findings demonstrate that safranal suppresses cell cycle re-entry of quiescent Pca cells in vitro and in vivo plausibly by repressing the transcriptional activity of two major transcriptional activators of Skp2, namely, E2F1 and NF-κB, through the downregulation of AKT phosphorylation and NF-κB signaling pathways, respectively.
    Matched MeSH terms: Proto-Oncogene Proteins c-akt
  18. Fulltext Antioxidant and Anti-Inflammatory Effects of Genus Gynura: A Systematic Review
    Tan JN, Mohd Saffian S, Buang F, Jubri Z, Jantan I, Husain K, et al.
    Front Pharmacol, 2020;11:504624.
    PMID: 33328981 DOI: 10.3389/fphar.2020.504624
    Background:Gynura species have been used traditionally to treat various ailments, such as fever, pain, and to control blood glucose level. This systematic review critically discusses studies regarding Gynura species that exhibited antioxidant and anti-inflammatory effects, thus providing perspectives and instructions for future research of the plants as a potential source of new dietary supplements or medicinal agents. Methods: A literature search from internet databases of PubMed, Scopus, Science Direct, e-theses Online Service, and ProQuest was carried out using a combination of keywords such as "Gynura," "antioxidant," "anti-inflammatory," or other related words. Research articles were included in this study if they were experimental (in vitro and in vivo) or clinical studies on the antioxidant or anti-inflammatory effects of Gynura species and if they were articles published in English. Results: Altogether, 27 studies on antioxidant and anti-inflammatory effects of Gynura species were selected. The antioxidant effects of Gynura species were manifested by inhibition of reactive oxygen species production and lipid peroxidation, modulation of glutathione-related parameters, and enzymatic antioxidant production or activities. The anti-inflammatory effects of Gynura species were through the modulation of inflammatory cytokine production, inhibition of prostaglandin E2 and nitric oxide production, cellular inflammatory-related parameters, and inflammation in animal models. The potential anti-inflammatory signaling pathways modulated by Gynura species are glycogen synthase kinase-3, nuclear factor erythroid 2-related factor 2, PPARγ, MAPK, NF-κB, and PI3K/Akt. However, most reports on antioxidant and anti-inflammatory effects of the plants were on crude extracts, and the chemical constituents contributing to bioactivities were not clearly understood. There is a variation in quality of studies in terms of design, conduct, and interpretation, and in-depth studies on the underlying mechanisms involved in antioxidant and anti-inflammatory effects of the plants are in demand. Moreover, there is limited clinical study on antioxidant and anti-inflammatory effects of Gynura species. Conclusion: This review highlighted antioxidant and anti-inflammatory effects of genus Gynura and supported their traditional uses to treat oxidative stress and inflammatory-related diseases. This review is expected to catalyze further studies on genus Gynura. However, extensive preclinical data need to be generated from toxicity and pharmacokinetic studies before clinical studies can be pursued for their development into clinical medicines to treat oxidative stress and inflammatory conditions.
    Matched MeSH terms: Proto-Oncogene Proteins c-akt
  19. Fulltext Tocotrienols and oxidative stress in ocytes and developing embryos
    Yuhaniza Shafinie Kamsani, Mohd Hamim Rajikin
    Journal of Clinical and Health Sciences, 2017;2:8-18.
    This review summarizes the impact of tocotrienols (TCTs) as antioxidants in minimizing
    oxidative stress (OS), particularly in embryos exposed to OS causing agents. OS level is
    increased, for example, by nicotine, a major alkaloid content in cigarette, which is also a source
    of exogenous reactive oxygen species (ROS). Increased nicotine-induced OS increases cell
    stress response, which is a common trigger leading to embryonic cell death. Having more
    profound anti-oxidative stress effects than its counterpart tocopherol, TCTs improve blastocyst
    implantation, foetal growth, pregnancy outcome and survival of the neonates affected by
    nicotine. In reversing cell developmental arrest caused by nicotine-induced OS, TCTs enhances
    PDK-1 expression in the P13K/Akt pathway and permit embryonic development beyond the 4-
    cell stage with the production of more morulae. At the cytoskeletal level, TCTs increase the
    number of nicotine-induced apoptotic cells, through caspase 8 activation in the mitochondria.
    TCTs facilitate rough endoplasmic reticulum (rER) stress-mediated apoptosis and autophagy,
    resulting from nicotine-induced OS. Reduced vesicular population in TCT supplemented
    oocytes on the other hand may suggest reduced secretion of apoptotic cell bodies thus probably
    minimizing vesicular apoptosis during oocyte maturation. Further extensive research is
    required to develop TCTs as a tool in specific therapeutic approaches to overcome the
    detrimental effects of OS.
    Matched MeSH terms: Proto-Oncogene Proteins c-akt
  20. Diosgenin, a steroidal saponin, and its analogs: Effective therapies against different chronic diseases
    Parama D, Boruah M, Yachna K, Rana V, Banik K, Harsha C, et al.
    Life Sci, 2020 Nov 01;260:118182.
    PMID: 32781063 DOI: 10.1016/j.lfs.2020.118182
    BACKGROUND: Chronic diseases are a major cause of mortality worldwide, and despite the recent development in treatment modalities, synthetic drugs have continued to show toxic side effects and development of chemoresistance, thereby limiting their application. The use of phytochemicals has gained attention as they show minimal side effects. Diosgenin is one such phytochemical which has gained importance for its efficacy against the life-threatening diseases, such as cardiovascular diseases, cancer, nervous system disorders, asthma, arthritis, diabetes, and many more.

    AIM: To evaluate the literature available on the potential of diosgenin and its analogs in modulating different molecular targets leading to the prevention and treatment of chronic diseases.

    METHOD: A detailed literature search has been carried out on PubMed for gathering information related to the sources, biosynthesis, physicochemical properties, biological activities, pharmacokinetics, bioavailability and toxicity of diosgenin and its analogs.

    KEY FINDINGS: The literature search resulted in many in vitro, in vivo and clinical trials that reported the efficacy of diosgenin and its analogs in modulating important molecular targets and signaling pathways such as PI3K/AKT/mTOR, JAK/STAT, NF-κB, MAPK, etc., which play a crucial role in the development of most of the diseases. Reports have also revealed the safety of the compound and the adaptation of nanotechnological approaches for enhancing its bioavailability and pharmacokinetic properties.

    SIGNIFICANCE: Thus, the review summarizes the efficacy of diosgenin and its analogs for developing as a potent drug against several chronic diseases.

    Matched MeSH terms: Proto-Oncogene Proteins c-akt
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