Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P31749 (AKT)
 22,954 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Metastatic cancer is a complex positive feedback loop system. Such as system has a tendency to acquire extreme robustness. Signaling pathways controlling that robustness can fail completely if an essential element from the signaling is removed. That element is a locus of fragility. Targeting that locus represents the best way to target the cancer robustness. This prospect presents another locus of fragility in signaling complex system network, controlling the cell cycle progression through the PI3K/AKT/mTOR/RAN pathway and cell migration and angiogenesis through the VEGF/PI3K/AKT/NO/ICAM-1 pathway. The locus of fragility of these pathways is AKT, which is regulated by a balance of catalase/H2O2 or by AKT inhibitor. Tiny and trivial perturbations such as change in redox state in the cells by antioxidant enzyme catalase, scavenging H2O2 signaling molecule, regulates robust signaling molecule AKT, abolishing its phosporilation and inducing cascading failure of robust signaling pathways for cell growth, proliferation, migration, and angiogenesis. An anticancer effect of the antioxidant is achieved through the AKT locus, by abolishing signals from growth factors VEGF, HGF, HIF-1alpha and H2O2. Previously reported locus of fragility nitric oxide (NO) and locus AKT are close in the complex signaling interactome network, but they regulate distinct signaling modules. Simultaneously targeted loci represents new principles in cancer robustness chemotherapy by blocking cell proliferation, migration, angiogenesis and inducing rather slow then fast apoptosis leading to slow eradication of cancer.
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PMID:AKT as locus of fragility in robust cancer system. 1842 70

Epidermal growth factor receptor (EGFR) targeting agents such as kinase inhibitors reduce tumor growth and progression. We have previously reported that EGFR is not only expressed by the tumor cells but by the tumor endothelial cells (EC) as well (Amin, D. N., Hida, K., Bielenberg, D. R., Klagsbrun, M., 2006. Tumor endothelial cells express epidermal growth factor receptor (EGFR) but not ErbB3 and are responsive to EGF and to EGFR kinase inhibitors. Cancer Res. 66, 2173-80). Thus, targeting tumor blood vessel EGFR may be a viable strategy for tumor growth inhibition. We describe here a melanoma xenograft model where the tumor cells express very little or no EGFR but the tumor blood vessels express activated EGFR. The EGFR kinase inhibitor, gefitinib (Iressa), retarded tumor growth with a size decrease of 38% compared to control mice, ostensibly due to targeting of the blood vessels. EC were isolated from tumors of gefitinib-treated mice. These EC were unable to proliferate in response to EGF and displayed relatively weaker activation of MAPK and AKT signaling in response to EGF compared to tumor EC isolated from vehicle-treated mice. In contrast, the tumor EC from gefitinib-treated mice expressed higher levels of VEGFR-2 both at the mRNA and protein level. In addition, these cells were less sensitive to EGFR kinase inhibitors in vitro but more sensitive to a VEGFR-2 kinase inhibitor. These results suggest that in tumor EC from gefitinib-treated mice there is a switch from dependence on EGFR activity to signaling via VEGFR-2. Our data provide a molecular rationale for combination therapies targeting both EGF and VEGF signaling on the tumor vasculature.
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PMID:Targeting EGFR activity in blood vessels is sufficient to inhibit tumor growth and is accompanied by an increase in VEGFR-2 dependence in tumor endothelial cells. 1844 31

Cancer is primarily a disease of old age, and that life style plays a major role in the development of most cancers is now well recognized. While plant-based formulations have been used to treat cancer for centuries, current treatments usually involve poisonous mustard gas, chemotherapy, radiation, and targeted therapies. While traditional plant-derived medicines are safe, what are the active principles in them and how do they mediate their effects against cancer is perhaps best illustrated by curcumin, a derivative of turmeric used for centuries to treat a wide variety of inflammatory conditions. Curcumin is a diferuloylmethane derived from the Indian spice, turmeric (popularly called "curry powder") that has been shown to interfere with multiple cell signaling pathways, including cell cycle (cyclin D1 and cyclin E), apoptosis (activation of caspases and down-regulation of antiapoptotic gene products), proliferation (HER-2, EGFR, and AP-1), survival (PI3K/AKT pathway), invasion (MMP-9 and adhesion molecules), angiogenesis (VEGF), metastasis (CXCR-4) and inflammation (NF-kappaB, TNF, IL-6, IL-1, COX-2, and 5-LOX). The activity of curcumin reported against leukemia and lymphoma, gastrointestinal cancers, genitourinary cancers, breast cancer, ovarian cancer, head and neck squamous cell carcinoma, lung cancer, melanoma, neurological cancers, and sarcoma reflects its ability to affect multiple targets. Thus an "old-age" disease such as cancer requires an "age-old" treatment.
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PMID:Curcumin and cancer: an "old-age" disease with an "age-old" solution. 1846 66

Neuroblastoma is a frequent pediatric tumor with a poor outcome in spite of aggressive treatment, even with autologous hematopoietic stem cell transplantation. The overall cure rate of 40% is unsatisfactory and new therapeutic strategies are urgently needed. AKT is a major mediator of survival signals that protect cells from apoptosis and regulate cell proliferation. The AKT signaling network is considered a key determinant of the biological aggressiveness of these tumors. In this article, the authors discuss the relation between activators of AKT in neuroblastoma, in particular, growth factors such as IGF-1, TRK, GDNF, VEGF and EGF, and their effects on tumoral proliferation, differentiation and apoptosis. Numerous other proteins interact with AKT in neuroblastoma. Several are relatively well characterized, such as PTEN and retinoic acid; others are new and potentially interesting, such as PKC and anaplastic lymphoma kinase. Specific inhibition of AKT has been studied, such as with LY249002, with significant effects on cell progression and apoptosis in tumoral cells. Moreover, a series of new drugs, such as geldanamycin and rapamycin, directly modify the expression of AKT in tumoral cells. Few specific inhibitors of AKT are available; less specific inhibitors are probably unsuitable therapeutic options in neuroblastoma. Drugs with a direct or indirect inhibitory effect on the AKT pathway, used alone or in combination with other drugs, seem to hold great promise as a new therapeutic modality in neuroblastoma.
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PMID:AKT pathway in neuroblastoma and its therapeutic implication. 1847 Oct 48

The mechanisms involved in the epithelial to mesenchymal transition (EMT) are integrated in concert with master developmental and oncogenic pathways regulating in tumor growth, angiogenesis, metastasis, as well as the reprogrammation of specific gene repertoires ascribed to both epithelial and mesenchymal cells. Consequently, it is not unexpected that EMT has profound impacts on the neoplastic progression, patient survival, as well as the resistance of cancers to therapeutics (taxol, vincristine, oxaliplatin, EGF-R targeted therapy and radiotherapy), independent of the "classical" resistance mechanisms linked to genotoxic drugs. New therapeutic combinations using genotoxic agents and/or EMT signaling inhibitors are therefore expected to circumvent the chemotherapeutic resistance of cancers characterized by transient or sustained EMT signatures. Thus, targeting critical orchestrators at the convergence of several EMT pathways, such as the transcription pathways NF-kappaB, AKT/mTOR axis, MAPK, beta-catenin, PKC and the AP-1/SMAD factors provide a realistic strategy to control EMT and the progression of human epithelial cancers. Several inhibitors targeting these signaling platforms are already tested in preclinical and clinical oncology. In addition, upstream EMT signaling pathways induced by receptor and nonreceptor tyrosine kinases (e.g. EGF-R, IGF-R, VEGF-R, integrins/FAK, Src) and G-protein-coupled receptors (GPCR) constitute practical options under preclinical research, clinical trials or are currently used in the clinic for cancer treatment: e.g. small molecule inhibitors (Iressa: targeting selectively the EGF-R; CP-751,871, AMG479, NVP-AEW541, BMS-536924, PQIP, AG1024: IGF-R; AZD2171, ZD6474: VEGF-R; AZD0530, BMS-354825, SKI606: Src; BIM-46174: GPCR; rapamycin, CCI-779, RAD-001: mTOR) and humanized function blocking antibodies (Herceptin: ErbB2; Avastin: VEGF-A; Erbitux: EGF-R; Abegrin: alphavbeta3 integrins). We can assume that silencing RNA and adenovirus-based gene transfer of therapeutic miR and dominant interferring expression vectors targeting EMT pathways and signaling elements will bring additional ways for the treatment of epithelial cancers. Identification of the factors that initiate, modulate and effectuate EMT signatures and their underlying upstream oncogenic pathways should provide the basis of more efficient strategies to fight cancer progression as well as genetic and epigenetic forms of drug resistance. This goal can be accomplished using global screening of human clinical tumors by EMT-associated cDNA, proteome, miRome, and tissue arrays.
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PMID:Molecular signature and therapeutic perspective of the epithelial-to-mesenchymal transitions in epithelial cancers. 1871 6

The proof of principle that a drug targeting mTOR can improve survival has been obtained recently from a large randomised trial using temsirolimus as a first-line therapy in patients with advanced poor prognostic renal cell carcinoma. Consistent data have recently shown the important role of the PI3K/AKT/mTOR signalling pathway in the regulation of crucial metabolic and mitotic functions of cancer cells and endothelial cells allowing a better understanding of the role of mTOR in controlling cancer cell proliferation and survival as well as tumour angiogenesis. As a result, rapamycin derivatives (rapalogues) that block mTOR/Raptor complex 1 were shown to exert direct antiproliferative effects against endometrial cancers, in which cancer cells frequently lose PTEN function as well as mantle cell lymphomas, in which cancer cell proliferation appears to be driven primarily by cyclin D1 overexpression. The overall antitumour effects of rapalogues in renal cell carcinoma appear to be more complex with tumour growth inhibition resulting from direct G1/S cell cycle blockage and/or apoptotic effects in carcinoma cells along with the inhibition of downstream signalling of the HIF1alpha-induced VEGF/VEGFR autocrine loop in endothelial cells shutting down the maintenance of tumour angiogenesis. Despite extensive cognitive researches, it is difficult to appraise which of those mechanisms is predominant in patients. This review focuses on mechanisms of action of rapalogues focusing on antitumour effects in patients with renal cell carcinoma.
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PMID:mTORC1 inhibitors: is temsirolimus in renal cancer telling us how they really work? 1879 63

NP506, the 3-{2,4-dimethyl-5-[2-oxo-5-(N'-phenylhydrazinocarbonyl)-1,2-dihydro-indol-3-ylidenemethyl]-1H-pyrrol-3-yl}-propionic acid, was designed as FGF receptor 1 inhibitor by computational study and found to be more active against endothelial proliferation of HUVEC after the rhFGF-2 stimulation than SU6668 with minimum effective dose of 10 microM. NP506 inhibited the tyrosine phosphorylation in FGF, VEGF, and PDGF receptors and the activation of extracellular signal-regulated kinase (ERK), c-Jun-N-terminal-kinase (JNK) and AKT after the rhFGF-2 stimulation. The introduction of the phenyl hydrazide motif to the position 5 of the pyrido[2,3-d]pyrimidine scaffold led to the inhibitory effect in two signaling pathways: inhibition of AKT activation in the phosphatidyl inositol 3'-kinase (PI13K)/AKT signaling pathway and the inhibition of ERK and JNK activation in MAPK pathway.
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PMID:5-Substituted pyrido[2,3-d]pyrimidine, an inhibitor against three receptor tyrosine kinases. 1911 Apr 22

Preclinical studies have shown the potential antitumour efficacy of monoclonal antibodies (MAbs) directed to the epidermal growth factor receptor (EGFR). In this report, we investigated the cytotoxic effects of the MAb matuzumab (EMD 72000) towards A431 cells and compared it to cetuximab. While cetuximab induced cell cycle arrest and inhibited A431 cell proliferation, matuzumab did not. Both MAbs inhibited growth factor induced EGFR, HER2 and AKT phosphorylation; however, only cetuximab inhibited ERK 1/2 phosphorylation. Taken together, the data indicate that each antibody may elicit different responses on EGFR downstream signalling pathways with a distinct impact on A431 cell line survival. When combined, MAbs synergistically inhibited cell proliferation and induced EGFR down-regulation with a strong inhibition of ERK1/2 and AKT phosphorylation. In addition, both MAbs efficiently inhibited VEGF expression and induced ADCC, highlighting their therapeutic potential in vivo when used either as a single agent or in combination.
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PMID:Different antiproliferative effects of matuzumab and cetuximab in A431 cells are associated with persistent activity of the MAPK pathway. 1916 13

Increased neovascularization is commonly observed in hemorrhagic plaques and associated with rupture of atherosclerotic lesions. This study aims to investigate whether hemin accumulated at the site of hematoma promotes neovascularization through affecting the growth and function of endothelial progenitor cells (EPCs) and the possible mechanism involved. Here we demonstrated that hemin promoted a significant increase in neovessel formation in matrigel plugs embedded in vivo and enhanced the proliferation and endothelial gene expression in EPCs in vitro. VEGF-induced migration response and the capability to incorporate into the vascular networks were markedly enhanced in hemin-treated EPCs. Hemin induced the phosphorylation of ERK and AKT but not p38 or JNK. The inhibition of AKT or ERK activation significantly attenuated the effect of hemin on cell proliferation. However, the enhanced migration response induced by hemin was significantly suppressed by the inhibition of AKT but not ERK. Hemin induced significant increase in reactive oxygen species (ROS) production and hemin-induced angiogenic response of EPCs was substantially reduced by treatment with N-acetylcysteine. Collectively, these data support that hemin-induced ROS mediates the activation of AKT and ERK signaling pathways, which in turn promotes the cell proliferation and function of EPCs. J. Cell. Physiol. 219: 617-625, 2009. (c) 2009 Wiley-Liss, Inc.
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PMID:Hemin promotes proliferation and differentiation of endothelial progenitor cells via activation of AKT and ERK. 1917 60

Recent advances in genomics, proteomics, bioinformatics and systems biology have unraveled the complex aberrant signaling networks in cancer. The knowledge accrued has dramatically increased the opportunities for discovery of novel molecular targets for drug development. Major emphasis is being laid on designing new therapeutic strategies targeting multiple signaling pathways for more effective disease management. However, the translation of in vitro findings to patient management often poses major challenges that limit their clinical efficacy. Here we will discuss how understanding the dysregulated signaling networks can explain the pitfalls in translating the laboratory findings from the bench-to-bedside and suggest novel approaches to overcome these problems using head and neck cancer as a prototype. The five year survival rates of HNSCC patients (about 50% at 5 years) have not improved significantly despite advancements in multimodality therapy including surgery, radiation and chemotherapy. Molecular targeted therapies with inhibitors of EGFR and VEGF either alone, or in combination with conventional treatments have shown limited improved efficacy. The key deregulated signaling pathways in head and neck squamous cell carcinoma (HNSCC) include EGFR, Ras, TGFbeta, NFkappaB, Stat, Wnt/beta-catenin and PI3-K/AKT/mTOR. The aberrant activities of these interrelated signaling pathways contribute to HNSCC development. In depth understanding of the cross-talks between these pathways and networks will form the basis of developing novel strategies for targeting multiple molecular components for more effective prevention and treatment of HNSCC.
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PMID:Overview of current and future biologically based targeted therapies in head and neck squamous cell carcinoma. 1928 26


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