Signaling via class IA Phosphoinositide 3-kinases (PI3K) in human, breast-derived cell lines.
Signaling via class IA Phosphoinositide 3-kinases (PI3K) in human, breast-derived cell lines.
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DOI：
10.1371/journal.pone.0075045
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发表时间：
2013
期刊：
影响因子：
3.7
通讯作者：
Stephens LR
中科院分区：
文献类型：
--
作者：
Juvin V;Malek M;Anderson KE;Dion C;Chessa T;Lecureuil C;Ferguson GJ;Cosulich S;Hawkins PT;Stephens LR
我们研究了I类磷脂酰肌醇3-激酶(PI3K)在人乳房来源的MCF10A(及其同基因衍生物)和MDA-MB 231和468细胞中的不同作用。I类PI3K是p110催化亚基(α，β，δ和γ)和p50-101调节亚基的异源二聚体，可使信号转导的磷脂酰肌醇(3，4，5)-三磷酸(PtdIns(3，4，5)P3)激活效应分子，如蛋白激酶B(PKB)，以及反应，如迁移。PtdIns(3，4，5)P3-3-磷酸酶和肿瘤抑制因子PTEN抑制这一途径。P110α，而不是其他p110，有一些癌突变变体，这些突变在癌症中很常见。基因序列分析表明，MCF10A细胞表达p110β>；>；α>；δ，但未检测到p110γ。尽管如此，表皮生长因子刺激的蛋白激酶B的磷酸化依赖于p110α-，而不是β-或δ-活性。表皮生长因子刺激的趋化作用也依赖于p110α，但不依赖于β或δ活性。在突变型p110α(H1047R或E545K)的单一内源性等位基因存在的基础上，p110α抑制剂可使p110PKB的磷酸化增加，而表皮生长因子的作用被完全逆转。表达任何一种癌突变体的细胞表现出更高的基础运动和EGF刺激的化学运动。然而，后者对PI3K抑制剂只有部分敏感。在PTEN−/−细胞中，PKB的基础磷酸化和表皮生长因子刺激的磷酸化显著增加，但对p110的依赖性在不同细胞类型之间是不同的。在mda-MB 468s中，PKB的磷酸化显著依赖于p110β的活性，但不依赖于α或δ的活性；在−/−MCF10A中，它仍然像亲本细胞一样依赖于p110α。令人惊讶的是，PTEN的缺失抑制了基础运动和EGF刺激的趋化运动。这些结果表明：p110α是表皮生长因子信号转导蛋白激酶B和趋化运动所必需的，但不是趋化所必需的；p110α的癌突变等位基因在没有表皮生长因子的情况下增强信号转导，并可能部分地通过敏锐地调节PI3K活性非依赖的机制来增加运动性。最后，我们证明了在没有β的情况下，并不存在上调p110 PTEN功能的通用机制。
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.
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影响因子：
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作者：
Burke, John E;Williams, Roger L
通讯作者：
Williams, Roger L
DOI：
10.1073/pnas.0808757105
发表时间：
2008-12-30
影响因子：
11.1
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DOI：
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发表时间：
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影响因子：
11.1
作者：
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影响因子：
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作者：
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