Signaling via class IA Phosphoinositide 3-kinases (PI3K) in human, breast-derived cell lines.
We have addressed the differential roles of class I Phosphoinositide 3-kinases (PI3K) in human breast-derived MCF10a (and iso-genetic derivatives) and MDA-MB 231 and 468 cells. Class I PI3Ks are heterodimers of p110 catalytic (α, β, δ and γ) and p50-101 regulatory subunits and make the signaling lip...
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2013-01-01
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| Online Access: | https://doi.org/10.1371/journal.pone.0075045 |
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| author | Veronique Juvin Mouhannad Malek Karen E Anderson Carine Dion Tamara Chessa Charlotte Lecureuil G John Ferguson Sabina Cosulich Phillip T Hawkins Len R Stephens |
| author_facet | Veronique Juvin Mouhannad Malek Karen E Anderson Carine Dion Tamara Chessa Charlotte Lecureuil G John Ferguson Sabina Cosulich Phillip T Hawkins Len R Stephens |
| author_sort | Veronique Juvin |
| collection | DOAJ |
| description | We have addressed the differential roles of class I Phosphoinositide 3-kinases (PI3K) in human breast-derived MCF10a (and iso-genetic derivatives) and MDA-MB 231 and 468 cells. Class I PI3Ks are heterodimers of p110 catalytic (α, β, δ and γ) and p50-101 regulatory subunits and make the signaling lipid, phosphatidylinositol (3,4,5)-trisphosphate (PtdIns(3,4,5)P3) that can activate effectors, eg protein kinase B (PKB), and responses, eg migration. The PtdIns(3,4,5)P3-3-phosphatase and tumour-suppressor, PTEN inhibits this pathway. p110α, but not other p110s, has a number of onco-mutant variants that are commonly found in cancers. mRNA-seq data shows that MCF10a cells express p110β>>α>δ with undetectable p110γ. Despite this, EGF-stimulated phosphorylation of PKB depended upon p110α-, but not β- or δ- activity. EGF-stimulated chemokinesis, but not chemotaxis, was also dependent upon p110α, but not β- or δ- activity. In the presence of single, endogenous alleles of onco-mutant p110α (H1047R or E545K), basal, but not EGF-stimulated, phosphorylation of PKB was increased and the effect of EGF was fully reversed by p110α inhibitors. Cells expressing either onco-mutant displayed higher basal motility and EGF-stimulated chemokinesis.This latter effect was, however, only partially-sensitive to PI3K inhibitors. In PTEN(-/-) cells, basal and EGF-stimulated phosphorylation of PKB was substantially increased, but the p110-dependency was variable between cell types. In MDA-MB 468s phosphorylation of PKB was significantly dependent on p110β, but not α- or δ- activity; in PTEN(-/-) MCF10a it remained, like the parental cells, p110α-dependent. Surprisingly, loss of PTEN suppressed basal motility and EGF-stimulated chemokinesis. These results indicate that; p110α is required for EGF signaling to PKB and chemokinesis, but not chemotaxis; onco-mutant alleles of p110α augment signaling in the absence of EGF and may increase motility, in part, via acutely modulating PI3K-activity-independent mechanisms. Finally, we demonstrate that there is not a universal mechanism that up-regulates p110β function in the absence of PTEN. |
| format | Article |
| id | doaj-art-0a3cd7d61ff64529aea09da82586974f |
| institution | OA Journals |
| issn | 1932-6203 |
| language | English |
| publishDate | 2013-01-01 |
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| spelling | doaj-art-0a3cd7d61ff64529aea09da82586974f2025-08-20T02:22:37ZengPublic Library of Science (PLoS)PLoS ONE1932-62032013-01-01810e7504510.1371/journal.pone.0075045Signaling via class IA Phosphoinositide 3-kinases (PI3K) in human, breast-derived cell lines.Veronique JuvinMouhannad MalekKaren E AndersonCarine DionTamara ChessaCharlotte LecureuilG John FergusonSabina CosulichPhillip T HawkinsLen R StephensWe have addressed the differential roles of class I Phosphoinositide 3-kinases (PI3K) in human breast-derived MCF10a (and iso-genetic derivatives) and MDA-MB 231 and 468 cells. Class I PI3Ks are heterodimers of p110 catalytic (α, β, δ and γ) and p50-101 regulatory subunits and make the signaling lipid, phosphatidylinositol (3,4,5)-trisphosphate (PtdIns(3,4,5)P3) that can activate effectors, eg protein kinase B (PKB), and responses, eg migration. The PtdIns(3,4,5)P3-3-phosphatase and tumour-suppressor, PTEN inhibits this pathway. p110α, but not other p110s, has a number of onco-mutant variants that are commonly found in cancers. mRNA-seq data shows that MCF10a cells express p110β>>α>δ with undetectable p110γ. Despite this, EGF-stimulated phosphorylation of PKB depended upon p110α-, but not β- or δ- activity. EGF-stimulated chemokinesis, but not chemotaxis, was also dependent upon p110α, but not β- or δ- activity. In the presence of single, endogenous alleles of onco-mutant p110α (H1047R or E545K), basal, but not EGF-stimulated, phosphorylation of PKB was increased and the effect of EGF was fully reversed by p110α inhibitors. Cells expressing either onco-mutant displayed higher basal motility and EGF-stimulated chemokinesis.This latter effect was, however, only partially-sensitive to PI3K inhibitors. In PTEN(-/-) cells, basal and EGF-stimulated phosphorylation of PKB was substantially increased, but the p110-dependency was variable between cell types. In MDA-MB 468s phosphorylation of PKB was significantly dependent on p110β, but not α- or δ- activity; in PTEN(-/-) MCF10a it remained, like the parental cells, p110α-dependent. Surprisingly, loss of PTEN suppressed basal motility and EGF-stimulated chemokinesis. These results indicate that; p110α is required for EGF signaling to PKB and chemokinesis, but not chemotaxis; onco-mutant alleles of p110α augment signaling in the absence of EGF and may increase motility, in part, via acutely modulating PI3K-activity-independent mechanisms. Finally, we demonstrate that there is not a universal mechanism that up-regulates p110β function in the absence of PTEN.https://doi.org/10.1371/journal.pone.0075045 |
| spellingShingle | Veronique Juvin Mouhannad Malek Karen E Anderson Carine Dion Tamara Chessa Charlotte Lecureuil G John Ferguson Sabina Cosulich Phillip T Hawkins Len R Stephens Signaling via class IA Phosphoinositide 3-kinases (PI3K) in human, breast-derived cell lines. PLoS ONE |
| title | Signaling via class IA Phosphoinositide 3-kinases (PI3K) in human, breast-derived cell lines. |
| title_full | Signaling via class IA Phosphoinositide 3-kinases (PI3K) in human, breast-derived cell lines. |
| title_fullStr | Signaling via class IA Phosphoinositide 3-kinases (PI3K) in human, breast-derived cell lines. |
| title_full_unstemmed | Signaling via class IA Phosphoinositide 3-kinases (PI3K) in human, breast-derived cell lines. |
| title_short | Signaling via class IA Phosphoinositide 3-kinases (PI3K) in human, breast-derived cell lines. |
| title_sort | signaling via class ia phosphoinositide 3 kinases pi3k in human breast derived cell lines |
| url | https://doi.org/10.1371/journal.pone.0075045 |
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