• Title, Summary, Keyword: AKT1

Search Result 570, Processing Time 0.071 seconds

AKT1 Inhibitory DNAzymes Inhibit Cell Proliferation and Migration of Thyroid Cancer Cells

  • Yang, Le;He, Jin-Ting;Guan, Hong;Sun, Ya-Dong
    • Asian Pacific Journal of Cancer Prevention
    • /
    • v.14 no.4
    • /
    • pp.2571-2575
    • /
    • 2013
  • AKT1 is a member of the serine/threoine AGC protein kinase family involved in thyroid cancer metabolism, growth, proliferation and survival. It is overexpressed in thyroid tumors. In this study, we designed two AKT1 specific DNAzymes (DRz1 and DRz2) that target AKT1 mRNA. The results showed that DRz1 could decrease the expression of AKT1 by 58%. Furthermore, DRz1 significantly inhibited cell proliferation, induced apoptosis and inhibited invasion in SW597 cells. In addition, down-regulation of survivin expression was associated with decreased caspase-3, VEGF and MMP2 in SW597 cells after 24 h. In our study, the efficacy of DRz1 in decreasing AKT1 protein levels were better than DRz2. AKT1-DRz1 might have anti-tumorigenic activity and may provide the basis for a novel therapeutic intervention in thyroid cancer treatment.

Effect of Overexpressed Ref-1 on AKT Phosphorylation for NO Production in Mouse Aortic Endothelial Cell Line (마우스 내피세포주 MAE의 NO 생성과정에서 과발현된 Ref-1의 AKT 활성 조절에 대한 연구)

  • Song, Ju-Dong;Lee, Sang-Kwon;Park, Young-Chul
    • Journal of Life Science
    • /
    • v.18 no.12
    • /
    • pp.1651-1656
    • /
    • 2008
  • Redox factor-1 (Ref-1) is essential for repair of oxidatively damaged DNA and also govern the reductive activation of many transcription factors. In this study, we examined the effect of overexpressed Ref-1 on AKT activation for nitric oxide (NO) production in mouse aortic endothelial (MAE) cells. Adenoviral-mediated overexpression of Ref-1 enhanced NO production in unstimulated- as well as bradykinin-stimulated MAE cells. Importantly, forced overexpression of Ref-1 induced direct phosphorylation of AKT in cells. And, a PI3K inhibitor wortmannin completely abolished the increase in AKT phosphorylation by stimulation of bradykinin and/or overexpressed Ref-1. In addition, inhibition of AKT activity with HA-tagged activation-deficient AKT suppressed Ref-1-induced endothelial NO synthase (eNOS) phosphorylation and resulted in a corresponding inhibition of unstimulated- and bradykinin-stimulated NO production. These results suggest that Ref-1 stimulates direct phosphorylation of AKT for eNOS enzyme activity in murine endothelial cells.

Discovery and Evaluation of Polymorphisms in the AKT2 and AKT3 Promoter Regions for Risk of Korean Lung Cancer

  • Sung, Jae-Sook;Park, Kyong-Hwa;Kim, Seung-Tae;Kim, Yeul-Hong
    • Genomics & Informatics
    • /
    • v.10 no.3
    • /
    • pp.167-174
    • /
    • 2012
  • AKT is a signal transduction protein that plays a central role in the tumorigenesis. There are 3 mammalian isoforms of this serine/threonine protein kinase-AKT1, AKT2, and AKT3-showing a broad tissue distribution. We first discovered 2 novel polymorphisms (AKT2 -9826 C/G and AKT3 -811 A/G), and we confirmed 6 known polymorphisms (AKT2 -9473 C/T, AKT2 -9151 C/T, AKT2 -9025 C/T, AKT2 -8618G/A, AKT3 -675 A/-, and AKT3 -244 C/T) of the AKT2 and AKT3 promoter region in 24 blood samples of Korean lung cancer patients using direct sequencing. To evaluate the role of AKT2 and AKT3 polymorphisms in the risk of Korean lung cancer, genotypes of the AKT2 and AKT3 polymorphisms (AKT2 -9826 C/G, AKT2 -9473 C/T, AKT2 -9151 C/T, AKT2 -9025 C/T, AKT2 -8618G/A, and AKT3 -675 A/-) were determined in 360 lung cancer patients and 360 normal controls. Statistical analyses revealed that the genotypes and haplotypes in the AKT2 and AKT3 promoter regions were not significantly associated with the risk of lung cancer in the Korean population. These results suggest that polymorphisms of the AKT2 and AKT3 promoter regions do not contribute to the genetic susceptibility to lung cancer in the Korean population.

Regulation of Skeletal Muscle Differentiation by Akt (Akt에 의한 근육세포의 분화 조절)

  • Woo, Dae-Han;Yun, Sung-Ji;Kim, Eun-Kyoung;Ha, Jung-Min;Shin, Hwa-Kyoung;Bae, Sun-Sik
    • Journal of Life Science
    • /
    • v.22 no.4
    • /
    • pp.447-455
    • /
    • 2012
  • Akt plays an important role in a variety of cellular physiologies such as growth, proliferation, and differentiation. In skeletal muscle, Akt has been implicated in regulating regeneration, hypertrophy, and atrophy. In this study, the role of Akt has been examined during skeletal muscle differentiation. Culturing C2C12 myoblasts under low serum (1% horse serum) and high density converted cell morphology from a round shape to an elongated and multi-nucleated shape. Morphological changes were initiated from day 2 of differentiation. In addition, the expression of both myogenin G and myogenin D was elevated from day 2 of differentiation. Skeletal muscle differentiation was abolished by silencing Akt1 or Akt2, but was significantly enhanced by the over-expression of either Akt1 or Akt2. The activation of Akt was observed from day 2 of differentiation and disappeared after day 7. The expression of kruppel-like factor 4 was observed from day 6 of differentiation. Moreover, this expression was blocked in cells silencing either Akt1 or Akt2. In addition, the promoter activity of kruppel-like factor 4 was significantly reduced in cells silencing Akt1 or Akt2. These results suggest that Akt regulates skeletal muscle differentiation through the regulation of kruppel-like factor 4 expression.

Direct Interaction Between Akt1 and Gcn5 and its Plausible Function on Hox Gene Expression in Mouse Embryonic Fibroblast Cells

  • Oh, Ji Hoon;Lee, Youra;Kong, Kyoung-Ah;Kim, Myoung Hee
    • Biomedical Science Letters
    • /
    • v.19 no.3
    • /
    • pp.266-269
    • /
    • 2013
  • Hox genes encode transcription factors important for anterior-posterior body patterning at early stages of embryonic development. However, the precise mechanisms by which signal pathways are stimulated to regulate Hox gene expression are not clear. In the previous study, protein kinase B alpha (Akt1) has been identified as a putative upstream regulator of Hox genes, and Akt1 has shown to regulate Gcn5, a prototypical histone acetyltransferase (HAT), in a negative way in mouse embryonic fibroblast (MEF) cells. Since the activity of HAT such as the CBP/p300, and PCAF (a Gcn5 homolog), was down-regulated by Akt through a phosphorylation at the Akt consensus substrate motif (RXRXXS/T), the amino acid sequence of Gcn5 protein was analyzed. Mouse Gcn5 contains an Akt consensus substrate motif as RQRSQS sequence while human Gcn5 does not have it. In order to see whether Akt1 directly binds to Gcn5, immunoprecipitation with anti-Akt1 antibody was carried out in wild-type (WT) mouse embryonic fibroblast (MEF) cells, and then western blot analysis was performed with anti-Akt1 and anti-Gcn5 antibodies. Gcn5 protein was detected in the Akt1 immunoprecipitated samples of MEFs. This result demonstrates that Akt1 directly binds to Gcn5, which might have contributed the down regulation of the 5' Hoxc gene expressions in wild type MEF cells.

Nuclear Akt promotes neurite outgrowth in the early stage of neuritogenesis

  • Park, Ji-Hye;Lee, Sang-Bae;Lee, Kyung-Hoon;Ahn, Jee-Yin
    • BMB Reports
    • /
    • v.45 no.9
    • /
    • pp.521-525
    • /
    • 2012
  • In addition to its pivotal role in neuronal survival, PI3K/Akt signaling is integral to neuronal differentiation and neurite outgrowth. However, the exact role of Akt in neuronal differentiation is still controversial. Here, we found that nuclear expression of CA-Akt resulted in unusual rapid neurite outgrowth and overexpression of KD-Akt caused multiple dendrite growth without specific axon elongation. Moreover, microarray data revealed that the expression of FOXQ1 expression was about 10-fold higher in cells with nuclear, active Akt than in control cells. Quantitative real-time PCR analysis showed that mRNA levels were upregulated in NLS-CA-Akt cells as compared to KD or EV cells. Furthermore, our FACS analysis demonstrated that overexpression of NLS-CA-Akt accumulate cells in the G1 phase within 24 h, fitting with the rapid sprouting of neuritis. Thus, our data implied that at least in this early time frame, the overexpression of nuclear, active Akt forced cells into neurite development through probably FOXQ1regulation.

Inhibitory Effects of Dithiolo-thione Derivative SWU-20009 on Akt Activity (Dithiolo-thione 계열 유도체 SWU-20009의 Akt활성 저해 효과)

  • 고종희;연승우;이홍섭;김태용;노동윤;신경순;홍순광;강상순
    • YAKHAK HOEJI
    • /
    • v.48 no.2
    • /
    • pp.105-110
    • /
    • 2004
  • Akt (or Protein Kinase B; PKB) is a serine/threonine kinase and is activated by phosphoinositide 3-kinase (PI3K) pathway. Recent evidence indicates that the abnormal activities or expression of Akt is closely associated with cancer, diabetes and neuro-degenerative diseases. These findings mean that Akt is likely to be a new therapeutic target for the treatment of disease. Here, we screened the effects of dithiolo-dithione derivatives such as SWU-20004, SWU-20009 and SWU-20025 on Akt activities. Among these compounds, only SWU-20009 (2-Thioxo-[1,3]dithiolo[4,5- $\beta$][1,4]dithiine-5,6-dicarboxylic acid dimethyl ester) inhibited the growth of KATOIII cell at micromolar range of concentration. Further investigation also revealed that SWU-20009 inhibited cellular Akt activity and induced apoptotic cell death.

LPS Increases 5-LO Expression on Monocytes via an Activation of Akt-Sp1/NF-${\kappa}B$ Pathways

  • Lee, Seung Jin;Seo, Kyo Won;Kim, Chi Dae
    • The Korean Journal of Physiology and Pharmacology
    • /
    • v.19 no.3
    • /
    • pp.263-268
    • /
    • 2015
  • 5-Lipoxygenase (5-LO) plays a pivotal role in the progression of atherosclerosis. Therefore, this study investigated the molecular mechanisms involved in 5-LO expression on monocytes induced by LPS. Stimulation of THP-1 monocytes with LPS ($0{\sim}3{\mu}g/ml$) increased 5-LO promoter activity and 5-LO protein expression in a concentration-dependent manner. LPS-induced 5-LO expression was blocked by pharmacological inhibition of the Akt pathway, but not by inhibitors of MAPK pathways including the ERK, JNK, and p38 MAPK pathways. In line with these results, LPS increased the phosphorylation of Akt, suggesting a role for the Akt pathway in LPS-induced 5-LO expression. In a promoter activity assay conducted to identify transcription factors, both Sp1 and NF-${\kappa}B$ were found to play central roles in 5-LO expression in LPS-treated monocytes. The LPS-enhanced activities of Sp1 and NF-${\kappa}B$ were attenuated by an Akt inhibitor. Moreover, the LPS-enhanced phosphorylation of Akt was significantly attenuated in cells pretreated with an anti-TLR4 antibody. Taken together, 5-LO expression in LPS-stimulated monocytes is regulated at the transcriptional level via TLR4/Akt-mediated activations of Sp1 and NF-${\kappa}B$ pathways in monocytes.

Synthesis and Akt1 Kinase Inhibitory Activity of 1,3,4-Thiadiazole Derivatives (1,3,4-Thiadiazole 유도체의 합성 및 Akt1 카이네이즈 저해 활성)

  • Yoo, Kyung-Ho;Kim, Se-Young;Ryu, Jae-Chun
    • Journal of the Korean Applied Science and Technology
    • /
    • v.25 no.3
    • /
    • pp.370-379
    • /
    • 2008
  • Akt, a serine/threonine protein kinase as a viral oncogene, is a critical regulator of PI3K-mediated cell proliferation and survival. On translocation, Akt is phosphorylated and activated, ultimately resulting in stimulation of cell growth and survival. As a part of our program toward the novel Akt1 inhibitors with potent activity over PI3K signaling pathway, we found primary hit compound 2 with an $IC_{50}$ value of $620\mu}M$ from protein kinase focused library. Based on the structural features of 2, new 1,3,4-thiadiazole derivatives were designed by the introduction of aromatic and heteroaromatic moieties onto thiadiazole nucleus. In this work, a series of 1,3,4-thiadiazole derivatives 1a-1 were synthesized and evaluated for Akt1 inhibitory activity.

Hydroquinone suppresses IFN-β expression by targeting AKT/IRF3 pathway

  • Kim, Yong;Kim, Han Gyung;Han, Sang Yun;Jeong, Deok;Yang, Woo Seok;Kim, Jung-Il;Kim, Ji Hye;Yi, Young-Su;Cho, Jae Youl
    • The Korean Journal of Physiology and Pharmacology
    • /
    • v.21 no.5
    • /
    • pp.547-554
    • /
    • 2017
  • Previous studies have demonstrated the role of hydroquinone (HQ), a hydroxylated benzene metabolite, in modulating various immune responses; however, its role in macrophage-mediated inflammatory responses is not fully understood. In this study, the role of HQ in inflammatory responses and the underlying molecular mechanism were explored in macrophages. HQ down-regulated the expression of interferon $(IFN)-{\beta}$ mRNA in LPS-stimulated RAW264.7 cells without any cytotoxicity and suppressed interferon regulatory factor (IRF)-3-mediated luciferase activity induced by TIR-domain-containing adapter-inducing interferon-${\beta}$ (TRIF) and TANK-binding kinase 1 (TBK1). A mechanism study revealed that HQ inhibited IRF-3 phosphorylation induced by lipopolysaccharide (LPS), TRIF, and AKT by suppressing phosphorylation of AKT, an upstream kinase of the IRF-3 signaling pathway. IRF-3 phosphorylation is highly induced by wild-type AKT and poorly induced by an AKT mutant, AKT C310A, which is mutated at an inhibitory target site of HQ. We also showed that HQ inhibited IRF-3 phosphorylation by targeting all three AKT isoforms (AKT1, AKT2, and AKT3) in RAW264.7 cells and suppressed IRF-3-mediated luciferase activities induced by AKT in HEK293 cells. Taken together, these results strongly suggest that HQ inhibits the production of a type I IFN, $IFN-{\beta}$, by targeting AKTs in the IRF-3 signaling pathway during macrophage-mediated inflammation.