These findings suggest that future therapies based on AKT inhibition may complement conventional treatments by controlling tumor cell invasion and metastasis.
Furthermore, expression of kinase dead AKT2(181 amino acid methionine [M]), and not kinase dead AKT1(179M) or AKT3(177M), was capable of blocking invasion induced by either human epidermal growth factor receptor-2 (HER-2) overexpression or by activation of PI3-K. Taken together, these data indicate that AKT2 mediates PI3-K-dependent effects on adhesion, motility, invasion, and metastasis in vivo.
In vitro studies using human thyroid cancer cells demonstrated that nuclear translocation of Akt 1 and pAkt were associated with cytoplasmic p27 and cell invasion and migration.
AKT kinases regulate diverse cellular processes including cell proliferation and survival, cell size and response to nutrient availability, tissue invasion and angiogenesis.
However, although Akt1 siRNA had no effect on cell migration or invasion, Akt2 siRNA effectively suppressed both activities, and Akt3 siRNA had moderate effectiveness.
However, intriguing findings reported by Yoeli-Lerner et al. in the November 23, 2005 issue of Molecular Cell, suggest a novel, antimetastasis function of Akt: activation of Akt1 inhibited invasion in some cancer cells.
Here we show that overexpression of activated myr-Akt1 in human breast cancer cells phosphorylates and thereby targets the tumor suppressor tuberous sclerosis complex 2 (TSC2) for degradation, leading to reduced Rho-GTPase activity, decreased actin stress fibers and focal adhesions, and reduced motility and invasion.
Here we showed that (a) CXCL12/CXCR4 axis is expressed in PC bone metastasis; (b) exogenous CXCL12 induced MMP-9 expression by PC cells; (c) bone stromal cells and bone tissue conditioned media induced the migration of PC cells in a CXCR4-dependent manner; (d) pharmacological inhibition of PI3 kinase and MAP kinase pathways abrogated CXCL12-induced MMP-9 expression and invasion of PC cells; (e) exogenous CXCL12 induced Akt1 phosphorylation is indispensable for proMMP-9 secretion, migration, and invasion of PC cells; (f) CXCR4 was localized to lipid rafts in PC cells and initiated Akt phosphorylation.
There was no correlation between p-AKT expression and clinicopathological characteristics, such as International Federation of Gynecology and Obstetrics stage, tumor grade, and myometrial invasion.
Phosphorylation of beta-catenin by AKT increases its transcriptional activity and promotes tumor cell invasion, indicating that AKT-dependent regulation of beta-catenin plays a critical role in tumor invasion and development.
Moreover, PIKE-A and its active and inactive mutants similarly enhance or antagonize U87MG cell survival and invasion, and their ability to do so is coupled with the catalytic effect they have on Akt activation.
In addition, we found that GnRH-I and GnRH-II interfered with activation of the phosphatidylinositol-3-kinase/AKT pathway that is well documented to stimulate proteolysis and invasion of ovarian cancer cells.
The BRCA2 inhibitory effect on cancer cell migration and invasion resulted from down-regulation of matrix metalloproteinase (MMP)-9 protein levels due to increased MMP-9 proteolysis, and was signaled through inhibition of PI3-kinase/AKT and activation of MAPK/ERK pathway.
Using ES-2 and SKOV-3 ovarian cancer cell lines, we studied the modulation of estrogen and progestin on cell migration and invasion as well as their effect on AKT, pAKT and nm23-H1 expression.
Since EF1alpha is often overexpressed in breast cancer, the consequences of EF1alpha increased levels for proliferation, survival and invasion will likely depend on the relative concentration of Akt1 and Akt2.
In the present study, small hairpin RNA (shRNA) expression constructs that target sequences of human COX-2, Akt1 and PIK3R1 were used to examine the proliferation and invasion inhibition effects on SGC7901 gastric adenocarcinoma cells and U251 glioma cells.
In the present study, small hairpin RNA (shRNA) expression constructs that target sequences of human Akt1 and PIK3R1 were used to examine the proliferation and invasion inhibition effects on SGC7901 gastric adenocarcinoma cells and U251 glioma cells.
Matrigel invasion assay, wound scratch assay and migration assay using commercial kit were performed. beta1 integrin expression and activation of its downstream molecules such as focal adhesion kinase (FAK), AKT and extracellular signal-regulated kinase (ERK) were examined by Western blot.
In contrast, a selective inducible nitric oxide synthase inhibitor, 1400W, upregulated the expression of IRS-1 protein and the phosphorylation of IRS-1, Akt/PKB, and glycogen synthase kinase-3beta, along with enhanced proliferation and invasion of Panc-1 cells expressing inducible nitric oxide synthase protein.