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)

Statins are currently used for the treatment of hypercholesterolemia. Recently, we demonstrated that cerivastatin also reduces the proliferation and invasion of aggressive breast cancer cells, MDA-MB-231. In this report, a molecular mechanism to explain its anti-cancer action is proposed by combining the study of cerivastatin effect on both gene expression (microarray) and signal transduction pathways. Firstly, the expression of 13 genes was modified by cerivastatin and confirmed at protein level. They could contribute to the inhibition of both cell proliferation (down-regulation of cyclin D1, PCNA, c-myc and up-regulation p21(Waf1), p19(INK4d), integrin beta8) and cell invasion, either directly (decrease in u-PA, MMP-9, u-PAR, PAI-1 and increase in anti-oncogenes Wnt-5a and H-cadherin) or indirectly by stimulating an anti-angiogenic gene (thrombospondin-2). The anti-angiogenic activity was confirmed by in vivo experiments. Secondly, we demonstrated that the biochemical mechanism of its anti-cancer action could be mainly explained by the inhibition of RhoA-dependent cell signalling. This hypothesis was supported by the fact that a RhoA inhibitor (C3 exoenzyme) or a dominant negative mutant RhoA (N19RhoA) induced similar effects to those of cerivastatin. In conclusion, cerivastatin, by preventing RhoA prenylation, inhibits (i) the RhoA/ROCK pathway, leading to defective actin stress fibres formation responsible for the loss of traction forces required for cell motility and (ii) the RhoA/FAK/AKT signalling pathway that could explain the majority of cancer-related gene modifications described above. Thus, the inhibition of RhoA cell signalling could be a good strategy in therapy of aggressive forms of breast cancer.
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PMID:Molecular mechanism of the anti-cancer activity of cerivastatin, an inhibitor of HMG-CoA reductase, on aggressive human breast cancer cells. 1253 31

Overexpressed epidermal growth receptor factor receptors (EGFRs) are thought to contribute to the malignant phenotype of human glioblastomas (GBMs), but the mechanism is not well understood. We found that SKMG-3 cells, a rare GBM cell line that maintains EGFR gene amplification in vitro, produced high levels of EGFR protein. The cells also expressed the related receptors HER2/neu and HER4, but not HER3. Immunoblots and tryptic phosphopeptide maps showed that the SKMG-3 EGFRs were intact and functional and that a subset of these receptors were spontaneously autophosphorylated. EGF treatment stimulated phosphorylation of the EGFRs as well as the downstream effectors Erk, AKT1, stat3 and c-Cbl. Under minimal growth conditions, the unstimulated SKMG-3 cells contained constitutively phosphorylated Erk and AKTI but no detectable stat3 DNA-binding complexes. The EGFR kinase inhibitor PD158780 reduced the constitutive phosphorylation of the receptor and Erk but not that of AKT1. In contrast, inhibition of phosphatidylinositol-3-kinase (PI3K) blocked the constitutive phosphorylation of Erk and AKT-1 but not the EGFR. We conclude that the SKMG-3 cells represent the subset of GBMs with amplified EGFR genes that overexpress intact receptors. The results also suggest that in some GBMs, signals from overexpressed EGFRs contribute to the constitutive phosphorylation of Erk, but these signals may not required for the constitutive activation of PI3K or AKT1.
Int J Cancer 2003 Mar 10
PMID:Spontaneous activation and signaling by overexpressed epidermal growth factor receptors in glioblastoma cells. 1253 15

Protein kinase B (PKB), a kinase downstream of phosphatidylinositol 3-kinase (PI3-kinase) provides anti-apoptotic and survival signals via phosphorylation of various targets. Inhibiting PI3-kinase with a 12 h exposure to 10 microM LY294002 induces levels of apoptosis of 30.39+/-1.53% in the KB-V1 multidrug resistant (MDR) cell line compared to 4.54+/-1.00% in drug sensitive KB-3-1 cells (P<0.001). This occurred in conjunction with a preferential reduction in activated PKB in MDR cells. These results suggest the PI3-kinase/PKB signalling pathway is important for the survival of MDR cells and inhibition of this pathway results in the selective induction of apoptosis in MDR cells.
Cancer Lett 2003 Feb 10
PMID:LY294002, an inhibitor of phosphatidylinositol-3-kinase, causes preferential induction of apoptosis in human multidrug resistant cells. 1253 74

Mutational alterations of PTEN and PIK3CA, which negatively and positively regulate PI3-kinase activity, respectively, have been observed in many types of human cancer. To explore the implication of PTEN and PIK3CA mutations in gastric tumorigenesis, we characterized the expression and mutation status of the genes in 126 gastric tissues and 15 cell lines. Expression of PTEN transcript was abnormally low in 5 of 15 (33%) cell lines and 20 of 55 (36%) primary carcinomas, whereas 0 of 71 noncancerous tissues including 16 benign tumors showed altered expression. Allelotyping analysis using an intragenic polymorphism (IVS4+109) revealed that 14 of 30 (47%) informative cases carried LOH of the gene, which is closely linked to low expression. The LOH rate was significantly higher in advanced tumors [12 of 19 (63%)] compared to early-stage tumors [2 of 11 (18%)] and more frequent in poorly differentiated tumors [9 of 13 (69%)] than well- or moderately differentiated tumors [5 of 17 (29%)]. Interestingly, however, none of the LOH tumors carried mutational disruption of the remaining allele, suggesting haploinsufficiency of PTEN in gastric tumorigenesis. Methylation studies revealed that PTEN pseudogene, but not PTEN, is methylated in cell lines and primary tumors, indicating that PTEN is not a target of epigenetic silencing in gastric cancers and that the pseudogene should be considered more carefully in methylation analysis of the PTEN promoter. Genomic amplification of PIK3CA was found in 9 of 15 (60%) cell lines and 20 of 55 (36.4%) primary tumors but in no noncancerous tissues. Furthermore, PIK3CA amplification was predominantly detected in tumors with no PTEN alterations, suggesting that mutations of PTEN and PIK3CA are mutually exclusive events in gastric tumorigenesis. Amplification of PIK3CA was strongly associated with increased expression of PIK3CA transcript and elevated levels of phospho-AKT. Collectively, our data reveal that 13 of 15 (87%) gastric cell lines and 31 of 55 (56%) primary carcinomas harbored either amplification of PIK3CA or abnormal reduction of PTEN. Mutually exclusive alterations of PTEN and PIK3CA also suggest that mutations of either gene could activate the PI3-kinase/AKT signaling pathway, which is directly linked to the malignant progression of gastric tumor cells.
Int J Cancer 2003 Apr 10
PMID:Frequent monoallelic deletion of PTEN and its reciprocal associatioin with PIK3CA amplification in gastric carcinoma. 1256 55

RON (Receptuer d'Origine Nantaise) is a member of the MET receptor tyrosine kinase family. RON is expressed in various cell types including macrophages, epithelial and hematopoietic cells. Its ligand, macrophage stimulating protein (MSP, also known as hepatocyte growth factor-like protein), is a multifunctional factor regulating cell growth and survival, adhesion and motility, cytokine production and phagocytosis. Accumulated data indicate that in addition to the regulation of normal cell functions, RON can be involved in cancer development and progression: (i). RON is overexpressed and constitutively active in some primary tumors and tumor cell lines; (ii). experimental mutations of RON cause oncogenic cell transformation, and (iii). RON mediates susceptibility to Friend-virus-induced erythroleukemia in mice. Constitutive activation of intracellular signaling pathways such as the PI-3 kinase/AKT, beta-catenin, MAPK and JNK pathways may underlie the molecular mechanism of RON-mediated oncogenic cell transformation. The present review describes RON-activated signaling pathways, which may play an important role in tumor formation and metastasis.
Curr Cancer Drug Targets 2003 Feb
PMID:Oncogenic signaling pathways activated by RON receptor tyrosine kinase. 1257 Jun 59

Various naturally occurring flavonoids have been found to be cancer-protective in chemically induced animal cancer models and synthetic flavonoid derivatives are being tested for potential chemotherapeutic usefulness in clinical trials. This report demonstrates that human oral squamous carcinoma cells (SCC) are significantly more sensitive to growth inhibition by the naturally occurring flavonoid, morin (3,5,7,2',4'-pentahydroxyflavone) than normal oral mucosa (NOMC) (SCC IC(50) = 115 microM; NOMC IC(50) = 173 micro M; P for difference = 0.009). Structure/function comparisons indicate that both the 2' and 4' hydroxyl groups in morin are required for its tumour selectivity. Morin causes growth arrest in G(2)/M, without inducing apoptosis, and this is associated with induction of GADD45 and phosphorylation and inactivation of the cell cycle kinase, cdc2. Morin also has pleiotropic effects on kinase signalling pathways, including inhibition of activation of protein kinase B by mitogens (but not extracellular-regulated kinases 1/2) and activation of the stress pathway kinases, Jun N-terminal kinase and p38 kinase. p38 kinase activation is functionally important since inhibition of its activation by the specific inhibitor SB202190 partially prevented cell cycle arrest by morin. However, analysis of dose-response relationships reveals that the enhanced tumour sensitivity to morin may be explained by the fact that activation of AKT is inhibited at lower concentrations of morin in carcinomas than normal oral mucosa, whereas Jun N-terminal kinase, p38 kinase and GADD45 are all induced in parallel with the same dose-response curves in carcinomas and normal oral mucosa.
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PMID:Enhanced sensitivity of human oral tumours to the flavonol, morin, during cancer progression: involvement of the Akt and stress kinase pathways. 1258 64

The G protein-coupled receptor oncogene (vGPCR) of the Kaposi's sarcoma (KS) associated herpesvirus (KSHV), an oncovirus implicated in angioproliferative neoplasms, induces angiogenesis by VEGF secretion. Accordingly, we found that expression of vGPCR in human umbilical vein endothelial cells (HUVEC) leads to immortalization with constitutive VEGF receptor-2/ KDR expression and activation. vGPCR immortalization was associated with anti-senescence mediated by alternative lengthening of telomeres and an anti-apoptotic response mediated by vGPCR constitutive signaling and KDR autocrine signaling leading to activation of the PI3K/AKT pathway. In the presence of the KS growth factor VEGF, this mechanism can sustain suppression of signaling by the immortalizing gene. We conclude that vGPCR can cause an oncogenic immortalizing event and recapitulate aspects of the KS angiogenic phenotype in human endothelial cells, pointing to this gene as a pathogenic determinant of KSHV.
Cancer Cell 2003 Feb
PMID:Kaposi's sarcoma associated herpesvirus G protein-coupled receptor immortalizes human endothelial cells by activation of the VEGF receptor-2/ KDR. 1262 Apr 8

The network of enzymes that contribute to the signal transduction of extracellular factors in pancreatic cancer is ever increasing. The classical Raf-MEK-ERK signaling cascade plays a crucial role in the regulation of apoptosis, proliferation, and metastasis of pancreatic cancer. Phosphatidylinositide-3-kinase also contributes to growth and prevents apoptosis in pancreatic cancer cells, acting in part via its downstream targets, PKB/AKT and the FRAP/p70s6k signaling complex. Recently, members of the PKC family of serine threonine kinases have emerged as novel modulators of transformation and cell cycle progression of pancreatic cancers. The novel PKD family of serine threonine kinases has just been detected in pancreatic cancer and awaits its functional characterization in these tumors.
Int J Gastrointest Cancer 2002
PMID:Novel protein kinases in pancreatic cell growth and cancer. 1262 11

Amphoterin is 1 ligand of the receptor for advanced glycation end products (RAGE). We studied expression of amphoterin and RAGE mRNA and proteins in colorectal carcinoma cells and investigated their associations with the invasive activities of cells exposed to advanced glycation end products (AGE). Expression of RAGE and amphoterin was examined in 4 colorectal carcinoma cell lines. All cell lines expressed both RAGE and amphoterin. The effects of RAGE and amphoterin on cell growth (MTT assay), migration (wound healing assay) and invasion (in vitro invasion assay) were tested by treatment of cells with RAGE and amphoterin antisense S-oligodeoxynucleotides (ODNs). Cell growth, migration and invasion were inhibited significantly in Colo320 and WiDr carcinoma cells treated with RAGE and amphoterin antisense S-ODNs compared with sense-treated cells. Differences in ligand activity between amphoterin and AGE were examined with AGE-bovine serum albumin (BSA). AGE-BSA decreased cell growth, migration and invasion of amphoterin antisense S-ODN-treated Colo320 and WiDr cells compared with those of cells treated with Colo320 conditioned medium. Phosphorylation of extracellular signal-regulated kinase-1/2, Rac1 and AKT and production of matrix metalloproteinase 9 were increased to a greater degree by amphoterin than by AGE-BSA. In contrast, production of inducible nitric oxide synthase and nuclear factor-kappaBp65 were increased to a greater degree by AGE-BSA than by amphoterin.
Int J Cancer 2003 May 10
PMID:Differential effects between amphoterin and advanced glycation end products on colon cancer cells. 1264 Jun 79

Hepatoma cells are known to be highly resistant to chemotherapy. Previously, we have found differential Taxol resistance in human and murine hepatoma cells. The aim of this study was to examine the effect of a multidrug resistance inhibitor, cyclosporin A in combination with Taxol on hepatoma in vitro and in vivo, and to identify the possible mechanism involved in Taxol resistance. Simultaneous treatment of cyclosporin A (0-10 microM) and Taxol (0.1 microM) inhibited cell growth in vitro. Cyclosporin A interfered with Taxol (0.1 microM)-induced AKT activation and BAD phosphorylation. Cyclosporin A combined with Taxol treatment augments caspase-9, -3 activation and loss of mitochondrial membrane potential in HepG2 cells. PI3 kinase inhibitor, wortmannin, or a dominant-negative AKT1 expression vector treatment partially enhanced Taxol-induced apoptosis indicating that PI3 kinase-AKT pathway was involved in Taxol-resistance pathway. Moreover, combination treatment reduced tumour growth in SCID and C57BL/6 mice as compared to either Taxol or cyclosporin A treatment. Our results indicate that the combination of cyclosporin A and Taxol is effective in the reversal of Taxol resistance through the inhibition of PI3 kinase-AKT1 pathway.
Br J Cancer 2003 Mar 24
PMID:Reversal of Taxol resistance in hepatoma by cyclosporin A: involvement of the PI-3 kinase-AKT 1 pathway. 1264 39


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