Comprehensive analysis of PTEN status in breast carcinomas
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ABSTRACT:
ORGANISM(S): Homo sapiens
SUBMITTER: Natalie Jones
PROVIDER: E-MEXP-3604 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
Similar Datasets
Project description:In an effort to identify genes whose expression is regulated by activated PI3K signaling, we performed microarray analysis and subsequent qRT-PCR on an isogenic set of PTEN gene-targeted human cancer cells. Numerous p53 effectors were upregulated following PTEN deletion, including p21, GDF15, PIG3, NOXA, and PLK2. Stable depletion of p53 led to reversion of the gene expression program. Western blots revealed that p53 was stabilized in HCT116 PTEN-/- cells via an Akt1-dependent and p14ARF-independent mechanism. Stable depletion of PTEN in untransformed human fibroblasts and epithelial cells also led to upregulation of p53 and senescent-like growth arrest. Simultaneous depletion of p53 rescued this phenotype, enabling PTEN-depleted cells to continue proliferating. Next, we tested whether oncogenic PIK3CA, like inactivated PTEN, could activate p53. Retroviral expression of oncogenic human PIK3CA in MCF10A cells led to activation of p53 and upregulation of p53-regulated genes. Stable depletion of p53 reversed these PIK3CA-induced expression changes and synergized with oncogenic PIK3CA in inducing anchorage-independent growth. Finally, targeted deletion of an endogenous allele of oncogenic but not wild-type PIK3CA in a human cancer cell line led to a reduction in p53 levels and a decrease in the expression of p53-regulated genes. These studies demonstrate that activation of PI3K signaling by mutations in PTEN or PIK3CA can lead to activation of p53-mediated growth suppression in human cells, indicating that p53 can function as a brake on PIP3-induced mitogenesis during human cancer pathogenesis. Experiment Overall Design: Two HCT116 PTEN+/+ cell lines (parental cells and a clone with random integration of the targeting vector) and three independently-derived HCT116 PTEN-/- cell lines were studied
2008-06-14 | E-GEOD-6263 | biostudies-arrayexpress
Project description:In an effort to identify genes whose expression is regulated by activated PI3K signaling, we performed microarray analysis and subsequent qRT-PCR on an isogenic set of PTEN gene-targeted human cancer cells. Numerous p53 effectors were upregulated following PTEN deletion, including p21, GDF15, PIG3, NOXA, and PLK2. Stable depletion of p53 led to reversion of the gene expression program. Western blots revealed that p53 was stabilized in HCT116 PTEN-/- cells via an Akt1-dependent and p14ARF-independent mechanism. Stable depletion of PTEN in untransformed human fibroblasts and epithelial cells also led to upregulation of p53 and senescent-like growth arrest. Simultaneous depletion of p53 rescued this phenotype, enabling PTEN-depleted cells to continue proliferating. Next, we tested whether oncogenic PIK3CA, like inactivated PTEN, could activate p53. Retroviral expression of oncogenic human PIK3CA in MCF10A cells led to activation of p53 and upregulation of p53-regulated genes. Stable depletion of p53 reversed these PIK3CA-induced expression changes and synergized with oncogenic PIK3CA in inducing anchorage-independent growth. Finally, targeted deletion of an endogenous allele of oncogenic but not wild-type PIK3CA in a human cancer cell line led to a reduction in p53 levels and a decrease in the expression of p53-regulated genes. These studies demonstrate that activation of PI3K signaling by mutations in PTEN or PIK3CA can lead to activation of p53-mediated growth suppression in human cells, indicating that p53 can function as a brake on PIP3-induced mitogenesis during human cancer pathogenesis. Keywords: PTEN genotype comparison
2006-11-15 | GSE6263 | GEO
Project description:Inactivation of Pten occurs by multiple mechanisms including epigenetic silencing, point mutations, insertion, and deletion, which are tissue dependent. Although frequent loss of heterozygosity around Pten locus and plausible involvement of epigenetic silencing have been reported in radiation-induced thymic lymphomas, the frequency of Pten inactivation and the spectrum of causal aberrations have not yet been extensively characterized. Here, we assessed the principal mode of inactivation by comprehensively analyzing expression and alterations of Pten gene in 23 radiation-induced thymic lymphomas developed in B6C3F1 mice. We found no evidence for methylation-associated silencing of Pten gene. Instead, we found complex structural abnormalities in 8 lymphomas (35%) that included missense and nonsense mutations, 1- and 3-bp insertions, and focal deletions. Sequencing of deletion breakpoints suggested that illegitimate V(D)J recombination and microhomology-mediated rearrangement were responsible for the focal deletions. Seven out of these 8 lymphomas had biallelic alterations, and 4 of them did not express any Pten protein. These aberrations of Pten were well coincided with downstream Akt phosphorylation on Ser473. In conclusion, Pten inactivation, which is frequently biallelic and is caused by a variety of structural abnormalities but not by epigenetic silencing, is involved in radiation-induced lymphomagenesis. Three thymic lymphomas were analyzed by array-CGH method.
2010-05-06 | E-GEOD-17751 | biostudies-arrayexpress
Project description:Hyperactivation of the phosphatydil-inositol-3' phosphate kinase (PI3K)/AKT pathway is observed in most NSCLCs, promoting proliferation, migration, invasion and resistance to therapy. AKT can be activated through several mechanisms that include loss of the negative regulator PTEN, activating mutations of the catalytic subunit of PI3K (PIK3CA) and/or mutations of AKT1 itself. However, number and identity of downstream targets of activated PI3K/AKT pathway are poorly defined. To identify the genes that are targets of constitutive PI3K/AKT signalling in lung cancer cells, we performed a comparative transcriptomic analysis of human lung epithelial cells (BEAS-2B) expressing active mutant AKT1 (AKT1-E17K), active mutant PIK3CA (PIK3CA-E545K) or that are silenced for PTEN. For each sample, 500 ng of total RNA were used to synthesize biotinylated cRNA with Illumina RNA Amplification Kit (Ambion, Austin, TX). Synthesis was carried out according to the manufacturersâ instructions. From each sample, technical triplicates were produced and 750 ng cRNA were hybridized for 18h to Human HT-12_V3_0_R1 Expression BeadChips (Illumina, San Diego, CA). Hybridized chips were washed and stained with streptavidin-conjugated Cy3 (GE Healthcare, Milan, Italy). BeadChips were dried and scanned with an Illumina Bead Array Reader (Illumina).
2016-12-01 | E-MTAB-5286 | biostudies-arrayexpress
Project description:Nuclear localization of PTEN is essential for its tumor suppressive role, and loss of nuclear PTEN is more prominent than cytoplasmic PTEN in many kinds of cancers. However, nuclear PTEN-specific regulatory mechanisms were rarely reported. Based on the finding that nuclear PTEN is more unstable than cytoplasmic PTEN. Thus, 293T cells were transiently transfected with plasmid encoding Flag-tagged PTEN along with empty vector, followed by affinity purification using an anti-Flag antibody, and the bound proteins were analyzed by liquid chromatography with tandem mass spectrometry (LC−MS/MS). Here we identify that F-box only protein 22 (FBXO22) induces ubiquitylation of nuclear but not cytoplasmic PTEN at lysine 221, which is responsible for the degradation of nuclear PTEN.
2020-04-22 | PXD017983 | Pride
Project description:Phosphatase and tensin homologue (PTEN) is the most frequently mutated tumor suppressor gene in human prostate cancer. Synthetic essentiality is defined as cancer that harbors a specific tumor suppressor deficiency is dependent on synthetic-essential genes for the malignant phenotypes. Recently, targeting such synthetic-essential genes has become an attractive treatment approach for cancers that acquire loss-of-function mutations in tumor suppressor genes. Here, we show that AT-rich interaction domain 4B (ARID4B) functions as a synthetic-essential gene in prostate tumorigenesis driven by PTEN deficiency. This functional interaction between ARID4B and PTEN is recapitulated in the mouse model carrying prostate-specific deletions of Pten and Arid4b in which ablation of ARID4B attenuated prostate cancer progression elicited by loss of PTEN. Although the tumor suppressor function of PTEN is most attributed to its lipid phosphatase activity that counters the PI3K action in cytoplasm, we identified the PTEN-ARID4B-PI3K axis in which nuclear PTEN inhibits expression of ARID4B, while ARID4B serves as a transcriptional activator of the PI3K subunits PIK3CA and PIK3R2 to trigger the PI3K/AKT pathway. Our study further demonstrated that the reciprocal binding of ARID4B and histone H1 to the PIK3CA and PIK3R2 promoters modulates chromatin condensation, indicating a mechanism by which ARID4B activates these promoters. Finally, a three-gene signature consisting of PTEN, ARID4B, and PI3K substantially improves the predictive power for tumor recurrence in human prostate cancer patients, underscoring the clinical significance of this newly identified PTEN-ARID4B-PI3K axis. These findings reveal a novel synthetic-essential relationship between ARID4B and PTEN, thus exposing a previously unidentified cancer-specific vulnerability, and supporting ARID4B as a potential therapeutic target for prostate cancer patients with PTEN mutations.
2019-08-23 | GSE116668 | GEO
Project description:Phosphatase and tensin homologue (PTEN) is the most frequently mutated tumor suppressor gene in human prostate cancer. Synthetic essentiality is defined as cancer that harbors a specific tumor suppressor deficiency is dependent on synthetic-essential genes for the malignant phenotypes. Recently, targeting such synthetic-essential genes has become an attractive treatment approach for cancers that acquire loss-of-function mutations in tumor suppressor genes. Here, we show that AT-rich interaction domain 4B (ARID4B) functions as a synthetic-essential gene in prostate tumorigenesis driven by PTEN deficiency. This functional interaction between ARID4B and PTEN is recapitulated in the mouse model carrying prostate-specific deletions of Pten and Arid4b in which ablation of ARID4B attenuated prostate cancer progression elicited by loss of PTEN. Although the tumor suppressor function of PTEN is most attributed to its lipid phosphatase activity that counters the PI3K action in cytoplasm, we identified the PTEN-ARID4B-PI3K axis in which nuclear PTEN inhibits expression of ARID4B, while ARID4B serves as a transcriptional activator of the PI3K subunits PIK3CA and PIK3R2 to trigger the PI3K/AKT pathway. Our study further demonstrated that the reciprocal binding of ARID4B and histone H1 to the PIK3CA and PIK3R2 promoters modulates chromatin condensation, indicating a mechanism by which ARID4B activates these promoters. Finally, a three-gene signature consisting of PTEN, ARID4B, and PI3K substantially improves the predictive power for tumor recurrence in human prostate cancer patients, underscoring the clinical significance of this newly identified PTEN-ARID4B-PI3K axis. These findings reveal a novel synthetic-essential relationship between ARID4B and PTEN, thus exposing a previously unidentified cancer-specific vulnerability, and supporting ARID4B as a potential therapeutic target for prostate cancer patients with PTEN mutations.
2019-08-23 | GSE116669 | GEO
Project description:Background: Breast cancer is a complex disease, encompassed by different clinically and molecularly stratified entities. In 2000, Perou and colleagues demonstrated that tumor phenotypic diversity correlates with differences in global gene expression patterns, which in turn reflect aspects of the biological behavior of the tumors. Gene expression profiling has distinguished sporadic breast tumor sub-classes with genetic, histopathological and clinical differences, however, little is known about the molecular classification of hereditary breast tumors. It has been recently suggested that most tumors arising in BRCA1 mutation carriers display a basal-like phenotype, with the percentages reported in different studies ranging from 44 to almost 100%. In the present study we used expression profiling to produce a molecular classification of BRCA1-associated breast tumors and applied an integrative approach to examine biological dependencies or differences. Methods and Findings: We used frozen tumor tissue from fourteen patients all of which harbored germline pathological mutations in BRCA1. Total RNA extraction, amplification and labeling with Cy5 were performed using standard protocols. Universal Human Reference RNA (Stratagene) was used as a reference and labeled with Cy3. Each pair of Cy3/Cy5 samples was hybridized onto the CNIO human OncoChip V2, which consists of a spotted microarray with 11,675 cDNA clones from the I.M.A.G.E. Consortium. Two channel ratios (Cy5/Cy3) for each spot were generated and quantified using GenePix Pro 5.1 (Axon Instruments, Inc., Union City, CA, USA). Data were normalized and filtered and multiple statistical analyses were performed. The data are deposited in the GEO database under the accession number GSE12350. A tissue microarray (TMA) containing an independent series of 15 BRCA1 tumors was used to validate some of the results obtained. We have described molecular signatures that define BRCA1 subclasses depending on the expression of the gene encoding for Estrogen Receptor, ESR1. Signatures were found to be molecularly associated with different biological processes and transcriptional regulatory programs. The signature of ESR1-positive tumors was mainly linked to cell proliferation-related processes and, therefore, regulated by the estrogen receptor, while the signature of ESR1-negative tumors was mainly linked to the immune response and possibly regulated by transcription factors of the REL/NF?B family. These signatures were then verified in an independent series of hereditary and sporadic breast tumors, which revealed a possible prognostic value for each subclass. Over-expression of immune response genes appears to be a common feature of ER-negative sporadic and hereditary breast cancer and is associated with good prognosis. Interestingly, the ESR1-negative tumors were sub-stratified into two groups presenting light differences in the magnitude of the expression of immune response transcripts and REL/NF?B transcription factors, and this could be dependent on the type of germline alteration. In addition, analysis of the human protein-protein interaction network provides the wiring diagram of critical molecular associations in BRCA1 tumorigenesis and identifies close relationships between the different signatures. Conclusions: In summary, in the present study we have established the gene expression profiling of a series of BRCA1 tumors and found that there is a further degree of heterogeneity beyond the main classification by the expression of ESR1 and the presence or absence of a basal-like phenotype. We have identified specific signatures for ESR1-positive and ESR1-negative BRCA1 tumors, the latter characterized by the enrichment of immune response and cell cycle genes, and have found that slight differences in the level of expression of the immune response stratify the ESR1-negative BRCA1 tumors into two additional sub-groups (A and B) with possible prognostic differences. NFkB could be a major driver responsible for the levels of both immune response and apoptotic genes in this group of tumors, which could in turn be related to the type of germline mutation in BRCA1. This study reveals the molecular complexity of BRCA1 breast tumors, which are found to display similarities to sporadic tumors, and suggests possible prognostic implications. 14 samples (primary breast tumors containing a BRCA1 mutation) were hybridized to a cDNA microarray in order to investigate the possible heterogeneity within the BRCA1 group.
2009-10-14 | E-GEOD-12350 | biostudies-arrayexpress
Project description:The PTEN tumor suppressor controls cell death and survival by regulating functions of various molecular targets. Whilst the role of PTEN lipid-phosphatase activity on PtdIns(3,4,5)P3 and inhibition of PI3K pathway is well characterized, the biological relevance of PTEN protein-phosphatase activity remains undefined. Using knock-in (KI) mice harbouring cancer-associated and functionally relevant missense mutations, we show that although loss of PTEN lipid-phosphatase function cooperates with oncogenic PI3K to promote rapid mammary tumorigenesis, the additional loss of PTEN protein-phosphatase activity triggered an extensive cell death response evident in early and advanced mammary tumors. Omics and drug-targeting studies revealed that PI3Ks act to reduce glucocorticoid receptor (GR) levels, which are rescued by loss of PTEN protein-phosphatase activity to restrain cell survival. The dual regulation of GR by PI3K and PTEN functions as a rheostat that can be exploited for the treatment of PTEN-loss driven cancers.
2020-10-15 | PXD016184 | Pride
Project description:To investigate the effects of PTEN activity on gene expression in 3D cultured glioblastoma cells and the contributions of PTEN's lipid and protein phosphatase activities to these effects. We expressed wild type PTEN, a catalytically dead mutant (C124S) or mutants selectively lacking protein or lipid phosphatase activity (Y138L and G129E respectively) in U87MG cells at physiological levels by transient unselected polyclonal lentiviral transduction. Cells were then seeded into 3D matrigel and RNA prepared after 15 hours.
2012-02-28 | E-MTAB-989 | biostudies-arrayexpress