Search results for "Protein kinase B"
showing 10 items of 191 documents
Holo-APP and G-protein-mediated signaling are required for sAPPa-induced activation of the Akt survival pathway
2014
International audience; Accumulating evidence indicates that loss of physiologic amyloid precursor protein (APP) function leads to reduced neuronal plasticity, diminished synaptic signaling and enhanced susceptibility of neurons to cellular stress during brain aging. Here we investigated the neuroprotective function of the soluble APP ectodomain sAPPa (soluble APPa), which is generated by cleavage of APP by a-secretase along the non-amyloidogenic pathway. Recombinant sAPPa protected primary hippocampal neurons and SH-SY5Y neuroblastoma cells from cell death induced by trophic factor deprivation. We show that this protective effect is abrogated in neurons from APP-knockout animals and APP-de…
In human retinoblastoma Y79 cells okadaic acid-parthenolide co-treatment induces synergistic apoptotic effects, with PTEN as a key player.
2013
Retinoblastoma is the most common intraocular malignancy of childhood. In developing countries, treatment is limited, long-term survival rates are low and current chemotherapy causes significant morbidity to pediatric patients and significantly limits dosing. Therefore there is an urgent need to identify new therapeutic strategies to improve the clinical outcome of patients with retinoblastoma. here, we investigated the effects of two natural compounds okadaic acid (OKa) and parthenolide (PN) on human retinoblastoma Y79 cells. For the first time we showed that OKa/PN combination at subtoxic doses induces potent synergistic apoptotic effects accompanied by lowering in p-akt levels, increasin…
In the literature: February 2020.
2020
The phosphatidylinositol-3-kinase (PI3K)/Akt and the mammalian target of rapamycin (mTOR) signaling pathways is one of the most frequently deregulated pathways in human cancers. This pathway controls multiple cellular processes, including metabolism, motility, proliferation, growth and survival. It can be aberrantly activated through multiple mechanisms, including diverse genomic alterations involving oncogenes and tumour suppressor genes.1 These alterations offer opportunities for therapeutic targeting of the pathway. PI3Kα protein complex is composed of regulatory (p85α) and catalytic (p110α) subunits. Pik3ca codes for p110α, which is the most frequently mutated oncogene across different …
Mcl-1 is an anti-apoptotic factor for human hepatocellular carcinoma
2005
Defects in apoptosis signaling in hepatocytes contribute to tumorigenesis in hepatocellular carcinoma (HCC). In addition, treatment with chemotherapeutic drugs is often ineffective in HCC patients due to the apoptosis resistance of cancer cells. Anti-apoptotic members of the Bcl-2 family, including myeloid cell leukemia-1 (Mcl-1), which regulate intrinsic apoptosis induction at the mito-chondrial level, are often overexpressed in human cancer, and are implicated with disease grade and prognosis. Yet, little is known about the role of Mcl-1 in HCC. In this study, we analyzed the relevance of Mcl-1 expression for the apop-tosis resistance of human HCC. Mcl-1 protein expression was considerabl…
Pleiotropic antitumor effects of the pan-HDAC inhibitor ITF2357 against c-Myc-overexpressing human B-cell non-Hodgkin lymphomas
2014
Histone deacetylases (HDAC) extensively contribute to the c-Myc oncogenic program, pointing to their inhibition as an effective strategy against c-Myc-overexpressing cancers. We, thus, studied the therapeutic activity of the new-generation pan-HDAC inhibitor ITF2357 (Givinostat®) against c-Myc-overexpressing human B-cell non-Hodgkin lymphomas (B-NHLs). ITF2357 anti-proliferative and pro-apoptotic effects were analyzed in B-NHL cell lines with c-Myc translocations (Namalwa, Raji and DOHH-2), stabilizing mutations (Raji) or post-transcriptional alterations (SU-DHL-4) in relationship to c-Myc modulation. ITF2357 significantly delayed the in vitro growth of all B-NHL cell lines by inducing G1 c…
The role of oxidative stress in apoptosis induced by the histone deacetylase inhibitor suberoylanilide hydroxamic acid in human colon adenocarcinoma …
2008
Histone deacetylase inhibitors (HDACIs) activate genes that promote cell cycle arrest and apoptosis in a number of tumor cells. This study showed that suberoylanilide hydroxamic acid (SAHA), a potent and commonly used HDACI, induced apoptosis in human colon adenocarcinoma HT-29 cells in a time- and dose-dependent manner. This effect was accompanied by the induction of oxidative stress, dissipation of mitochondrial transmembrane potential and activation of executioner caspases. Moreover, SAHA increased the levels of phosphorylated active forms of p38 and JNK. The addition of either the antioxidant N-acetylcysteine or the specific inhibitor of NADPH oxidase diphenylene iodonium chloride reduc…
MUC1 oncoprotein promotes refractoriness to chemotherapy in thyroid cancer cells.
2007
Abstract Overexpression of MUC1 oncoprotein is frequently observed in cancer and contributes to confer resistance to genotoxic agents. Papillary, follicular, and anaplastic thyroid carcinomas are the three forms of thyroid epithelial cancer. Anaplastic tumors are less differentiated and extremely aggressive, characterized by a poor prognosis. Little is known about the role of MUC1 in thyroid cancer. We recently showed that autocrine production of interleukin (IL)-4 and IL-10 controls thyroid cancer cell survival, growth, and resistance to chemotherapy through activation of Janus-activated kinase/signal transducers and activators of transcription (JAK/STAT) and phosphatidylinositide 3′-OH ki…
AKT-independent signaling downstream of oncogenic PIK3CA mutations in human cancer.
2009
SummaryDysregulation of the phosphatidylinositol 3-kinase (PI3K) signaling pathway occurs frequently in human cancer. PTEN tumor suppressor or PIK3CA oncogene mutations both direct PI3K-dependent tumorigenesis largely through activation of the AKT/PKB kinase. However, here we show through phosphoprotein profiling and functional genomic studies that many PIK3CA mutant cancer cell lines and human breast tumors exhibit only minimal AKT activation and a diminished reliance on AKT for anchorage-independent growth. Instead, these cells retain robust PDK1 activation and membrane localization and exhibit dependency on the PDK1 substrate SGK3. SGK3 undergoes PI3K- and PDK1-dependent activation in PI…
Abstract B154: A first-in-human trial of GDC-0068: A novel, oral, ATP-competitive Akt inhibitor, demonstrates robust suppression of the Akt pathway i…
2011
Abstract GDC-0068 is a highly selective ATP-competitive small molecule that inhibits all three isoforms of Akt with IC50 values of 5 to 30 nM. GDC-0068 selectively inhibits cancer cells with activated Akt signaling (e.g. via PTEN loss or PIK3CA mutations). Patients with advanced solid tumors were treated with GDC-0068 using a 3+3 escalation design. GDC-0068 was dosed PO QD on a 21-day on, 7-day off schedule; endpoints included safety, pharmacokinetics (PK) and determination of pathway knockdown. Pharmacodynamics (PD) endpoints in surrogate tissue [platelet rich plasma (PRP)] were evaluated in all patients. In addition, at least two patients per cohort had pre- and on-treatment (day 15) tumo…
Shikonin and its derivatives inhibit the epidermal growth factor receptor signaling and synergistically kill glioblastoma cells in combination with e…
2015
Overexpression and mutation of the epidermal growth factor receptor (EGFR) gene play a causal role in tumorigenesis and resistance to treatment of glioblastoma (GBM). EGFR inhibitors such as erlotinib are currently used for the treatment of GBM; however, their efficacy has been limited due to drug resistance. New treatment strategies are therefore urgently needed. Shikonin, a natural naphthoquinone, induces both apoptosis and necroptosis in human glioma cells, but the effectiveness of erlotinib-shikonin combination treatment as well as the underlying molecular mechanisms is unknown yet. In this study, we investigated erlotinib in combination with shikonin and 14 shikonin derivatives in pare…