Mutationally-activated PI3’-kinase-a promotes de-differentiation of lung tumors initiated by the BRAFV600E oncoprotein kinase
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PROVIDER: PRJNA507606 | ENA |
REPOSITORIES: ENA
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Project description:Human lung adenocarcinoma exhibits a propensity for de-differentiation, which complicates diagnosis and treatment, and predicts for poor overall patient survival. In genetically engineered mouse (GEM) models of lung cancer, expression of the BRAFV600E oncoprotein kinase initiates the growth of benign tumors that retain characteristics of their cell of origin, alveolar type II (ATII) pneumocytes. Cooperating genetic alterations such as silencing of the PTEN tumor suppressor or expression of mutationally-activated PI3-kinase-a (PIK3CAH1047R) promote malignant progression of such benign tumors to malignant adenocarcinoma, though their effects on differentiation status are unknown. To address this in vivo, we generated a new conditional BrafCAT allele in which Cre-mediated recombination leads to expression of a bi-cistronic mRNA encoding both BRAFV600E and the tdTomato fluorescent protein. Using this model, we demonstrate that coincident expression of BRAFV600E and PIK3CAH1047R in ATII pneumocytes leads to rapid and widespread cell de-differentiation. Surprisingly, the combined effects of BRAFV600E and PIK3CAH1047R on ATII pneumocyte identity occurred without loss of expression of the lung lineage transcription factors NKX2.1, FOXA1, or FOXA2. Instead, we demonstrate a novel role of PGC1α in maintaining pneumocyte identity, which is lost upon PIK3CAH1047R expression. These findings provide additional insight into how two of the most commonly mutated growth factor signaling pathways contribute to the pathogenesis of lung adenocarcinoma.
2019-03-19 | GSE123126 | GEO
Project description:RAS signalling through Phosphoinositide 3-kinase (PI3-Kinase) has been shown to have an essential role in tumour initiation and maintenance. RAS also regulates cell motility and tumor invasiveness, but the role of direct RAS binding to PI3-Kinase in this remains uncertain. Here, we provide evidence that disruption of RAS interaction with PI3-Kinase p110adecreases cell motility and prevents activation of Rac GTPase. Analysis of gene expression in cells lacking RAS interaction with p110areveals increased levels of the extracellular matrix glycoprotein Reelin and activation of its downstream pathway resulting in upregulation of E-Cadherin expression. Induction of the Reelin / E-Cadherin axis is also observed in Kras mutant lung tumours that are regressing due to blockade of RAS interaction with PI3-Kinase. Furthermore, loss of Reelin correlates with decreased survival of lung and breast cancer patients. Reelin thus plays a role in restraining RAS and PI3-kinase promotion of cell motility and potentially tumour metastasis.
2016-02-12 | GSE77843 | GEO
Project description:RAS signalling through Phosphoinositide 3-kinase (PI3-Kinase) has been shown to have an essential role in tumour initiation and maintenance. RAS also regulates cell motility and tumor invasiveness, but the role of direct RAS binding to PI3-Kinase in this remains uncertain. Here, we provide evidence that disruption of RAS interaction with PI3-Kinase p110adecreases cell motility and prevents activation of Rac GTPase. Analysis of gene expression in cells lacking RAS interaction with p110areveals increased levels of the extracellular matrix glycoprotein Reelin and activation of its downstream pathway resulting in upregulation of E-Cadherin expression. Induction of the Reelin / E-Cadherin axis is also observed in Kras mutant lung tumours that are regressing due to blockade of RAS interaction with PI3-Kinase. Furthermore, loss of Reelin correlates with decreased survival of lung and breast cancer patients. Reelin thus plays a role in restraining RAS and PI3-kinase promotion of cell motility and potentially tumour metastasis. MEFs with or without RAS binding to p110a were seeded in a 10cm dish and left to attach during 24 hours. Full serum media was then removed and media with no FBS was added to the plates. Starvation was carried out during a period of 16 hours (over night starvation). Assay was performed in triplicates: for each genotype two diferent fibroblasts clones (and a mix of both of the clones) were used on the analysis. After starvation RNA was extracted using RNAsy kit (Quiagen). RNA was quantified and sent to Oxford Gene Technology microarray facility.
2016-02-12 | E-GEOD-77843 | biostudies-arrayexpress
Project description:We sought to determine genes whose expression changed upon treatment with a selective inhibitor of class I PI3 kinase.
2010-05-25 | GSE20719 | GEO
Project description: Not available
| S-EPMC6711745 | biostudies-literature
Project description:We sought to determine genes whose expression changed upon treatment with a selective inhibitor of class I PI3 kinase. Total of 6 samples: cells were treated with GDC-0941 at a concentration of 1mM for 6 hours (3 replicates) and control (3 replicates)
2010-06-08 | E-GEOD-20719 | biostudies-arrayexpress
Project description:Role of p110a subunit of PI3-kinase in skeletal muscle mitochondria
| PRJNA511896 | ENA
Project description:Somatic NOTCH1 mutations are found in ~60% of T lineage acute lymphoblastic leukemias (T-ALLs). Notch1 is cleaved by γ secretase to generate activated Notch intracellular domain (NICD) proteins. The NOTCH1 mutations found in T-ALL constitutively activate Notch1 signaling by increasing NICD levels. Genetic alterations in components of the Ras/PI3 kinase (PI3K)/Akt pathway are also highly prevalent in T-ALL, and often coexist with NOTCH1 mutations. Exposing a T-ALL cell line to the PI3 kinase (PI3K) inhibitor GDC-0941 generated drug resistant clones that down-regulated NICD expression. To address the in vivo relevance of this unexpected observation, we transplanted primary wild-type (WT) and KrasG12D mutant T-ALLs into recipient mice, and treated them with GDC-0941 alone and in combination with the MEK inhibitor PD0325901 (PD901). Although many leukemias responded dramatically to these targeted agents in vivo, drug-resistant clones invariably emerged. Multiple resistant T-ALLs lost NICD expression through mechanisms that included loss of Notch1 mutations found in the parental T-ALL. These GDC-0941-resistant leukemias exhibited reduced expression of many Notch1 target genes, elevated levels of phosphorylated Akt (pAkt), and displayed cross-resistance to γ secretase inhibitors (GSIs). Consistent with these data, inhibiting Notch1 activity in T-ALL cells enhanced PI3K signaling, providing a likely mechanism for in vivo selection against clones with Notch1 pathway activation. Thus, oncogenic Notch1 mutations that promote clonal outgrowth during malignant transformation unexpectedly “switch” to become deleterious during treatment with a PI3K inhibitor. These data advance our understanding of T-ALL pathogenesis and have implications for implementing new therapeutic regimens. We analyzed 28 mouse T-ALL samples obtained after in vivo treatment with GDC-0941 alone or GDC-0941 + PD0325901. These T-ALL samples are either Kras wild type or harbor a KrasG12D mutations.
2014-06-24 | E-GEOD-48260 | biostudies-arrayexpress
Project description:Somatic NOTCH1 mutations are found in ~60% of T lineage acute lymphoblastic leukemias (T-ALLs). Notch1 is cleaved by γ secretase to generate activated Notch intracellular domain (NICD) proteins. The NOTCH1 mutations found in T-ALL constitutively activate Notch1 signaling by increasing NICD levels. Genetic alterations in components of the Ras/PI3 kinase (PI3K)/Akt pathway are also highly prevalent in T-ALL, and often coexist with NOTCH1 mutations. Exposing a T-ALL cell line to the PI3 kinase (PI3K) inhibitor GDC-0941 generated drug resistant clones that down-regulated NICD expression. To address the in vivo relevance of this unexpected observation, we transplanted primary wild-type (WT) and KrasG12D mutant T-ALLs into recipient mice, and treated them with GDC-0941 alone and in combination with the MEK inhibitor PD0325901 (PD901). Although many leukemias responded dramatically to these targeted agents in vivo, drug-resistant clones invariably emerged. Multiple resistant T-ALLs lost NICD expression through mechanisms that included loss of Notch1 mutations found in the parental T-ALL. These GDC-0941-resistant leukemias exhibited reduced expression of many Notch1 target genes, elevated levels of phosphorylated Akt (pAkt), and displayed cross-resistance to γ secretase inhibitors (GSIs). Consistent with these data, inhibiting Notch1 activity in T-ALL cells enhanced PI3K signaling, providing a likely mechanism for in vivo selection against clones with Notch1 pathway activation. Thus, oncogenic Notch1 mutations that promote clonal outgrowth during malignant transformation unexpectedly “switch” to become deleterious during treatment with a PI3K inhibitor. These data advance our understanding of T-ALL pathogenesis and have implications for implementing new therapeutic regimens.
2014-06-24 | GSE48260 | GEO
Project description:Gliomas are primary brain tumors with poor prognosis that exhibit frequent abnormalities in phosphatidylinositol 3-kinase (PI3 kinase) signaling. We investigated the molecular mechanism of action of the isoform-selective class I PI3 kinase and mTOR inhibitor PI-103 in human glioma cells. The potent inhibitory effects of PI-103 on the PI3 kinase pathway were quantified. PI-103 and the mTOR inhibitor rapamycin both inhibited ribosomal protein S6 phosphorylation but there were clear differences in the response of upstream components of the PI3 kinase pathway, such as phosphorylation of Thr308-AKT, that were inhibited by PI-103 but not rapamycin. Gene expression profiling identified altered expression of genes encoding regulators of the cell cycle and cholesterol metabolism, and genes modulated by insulin or IGF1 signaling, rapamycin treatment or nutrient starvation. PI-103 decreased expression of positive regulators of G1/S phase progression and increased expression of the negative cell cycle regulator p27kip1. A reversible PI-103-mediated G1 cell cycle arrest occurred without significant apoptosis, consistent with the altered gene expression detected. PI-103 induced vacuolation and processing of LC-3i to LC-3ii, which are features of an autophagic response. In contrast to PI-103, LY294002 and PI-387 induced apoptosis, indicative of likely off-target effects. PI-103 interacted synergistically or additively with cytotoxic agents used in the treatment of glioma, namely vincristine, BCNU and temozolomide. Compared to individual treatments, the combination of PI-103 with temozolomide significantly improved the response of U87MG human glioma xenografts. Our results support the therapeutic potential for PI3 kinase inhibitors with a PI-103-like profile as therapeutic agents for the treatment of glioma. Keywords: Key words: PI-103, glioma, PI3 kinase, mTOR, cell cycle, cytostasis
2009-04-21 | GSE12175 | GEO