PTEN regulated PI3K-p110 and AKT isoform plasticity controls metastatic prostate cancer progression
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE242387 | GEO | 2023/11/01
REPOSITORIES: GEO
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Project description:The PIP3/PI3K network is a central regulator of metabolism and is frequently activated in cancer, commonly by loss of the PIP3/PI(3,4)P2-phosphatase, PTEN. Despite huge investment, the drivers of the PI3K network in normal tissues and how they adapt to overactivation are unclear. We find that in healthy mouse prostate PI3K activity is driven by RTK/IRS signalling and constrained by pathway-feedback. In the absence of PTEN, the network is dramatically remodelled. A poorly understood, YXXM- and PIP3/PI(3,4)P2-binding PH domain-containing, adaptor, PLEKHS1, became the dominant activator and was required to sustain PIP3, AKT-phosphorylation and growth in PTEN-null prostate. This was because PLEKHS1 evaded pathway-feedback and experienced enhanced PI3K- and SRC-family kinase-dependent phosphorylation of Y258XXM, eliciting PI3K-activation. hPLEKHS1-mRNA and activating-Y419-phosphorylation of hSRC correlated with PI3K-pathway activity in human prostate cancers. We propose that in PTEN-null cells, receptor-independent, SRC-dependent tyrosine-phosphorylation of PLEKHS1 creates positive-feedback that escapes homeostasis, drives PIP3-signalling and supports tumour progression.
2023-08-23 | PXD043239 | Pride
Project description:PTEN loss or PI3K/AKT signaling pathway activation correlates with human prostate cancer progression and metastasis. However, in preclinical murine models, deletion of Pten alone fails to mimic the significant metastatic burden that frequently accompanies the end stage of human disease. To identify additional pathway alterations that cooperate with PTEN loss in prostate cancer progression, we surveyed human prostate cancer tissue microarrays and found that the RAS/MAPK pathway is significantly elevated both in primary and metastatic lesions. In an attempt to model this event, we crossed conditional activatable K-rasG12D/WT mice with the prostate conditional Pten deletion model we previously generated. Although RAS activation alone cannot initiate prostate cancer development, it significantly accelerated progression caused by PTEN loss, accompanied by epithelial-to-mesenchymal transition (EMT) and macrometastasis with 100% penitence. A novel stem/progenitor subpopulation with mesenchymal characteristics was isolated from the compound mutant prostates, which was highly metastatic upon orthotopic transplantation. Importantly, inhibition of RAS/MAPK signaling by PD325901, a MEK inhibitor, significantly reduced the metastatic progression initiated from transplanted stem/progenitor cells. Collectively, these data indicate that activation of RAS/MAPK signaling serves as a potentiating second hit to alteration of the PTEN/PI3K/AKT axis and co-targeting both pathways is highly effective in preventing the development of metastatic prostate cancers. Murine mutants with prostate specific loss of Pten and K-ras activation (K-rasG12D) under regulation of the probasin promoter developed high grade, invasive prostate cancer. RNA was extracted from dissected prostate lobes from individual mutants with pathology thought to closely mimic human disease. Prostate tissue was subject to RNA extraction and hybridization on Affymetrix cDNA microarrays.
2012-02-28 | E-GEOD-34839 | biostudies-arrayexpress
Project description:Activation of the PI3K pathway in estrogen receptor α (ER)-positive (+) breast cancer is associated with reduced ER expression and activity, luminal B subtype, and poor outcome. PTEN is a negative regulator of the PI3K pathway typically lost in ER-negative (-) breast cancer. To clarify the effect of PTEN down-regulation on the response of ER+/HER2- breast cancer to endocrine therapy, we established reduced PTEN cell models using inducible knockdown. We found that only moderate PTEN reduction is sufficient to enhance PI3K signaling, generate a gene signature associated with luminal B subtype, and cause endocrine resistance. Combining endocrine therapy with mTOR, AKT, or MEK inhibitors improves antitumor activity, but the efficacy varies by type of endocrine therapy and the specific inhibitor. Fulvestrant plus an AKT inhibitor is the most potent combination when PTEN is reduced, inducing apoptosis and tumor regression. This combination deserves further study in patients with PI3K pathway activation.
2014-06-30 | GSE53300 | GEO
Project description:Diffuse large B-cell lymphoma (DLBCL) represents a heterogeneous diagnostic category with distinct molecular subtypes that can be deM-oM-,M-^Aned by gene expression proM-oM-,M-^Aling. However, even within these deM-oM-,M-^Aned subtypes, heterogeneity prevails. To further elucidate the pathogenesis of these entities, we determined the expression of the tumor suppressor phosphatase and tensin homolog (PTEN) in 248 primary DLBCL patient samples. These analyses revealed that loss of PTEN was detectable in 55% of germinal center B-cell-like (GCB) DLBCLs, whereas this abnormality was found in only 14% of non-GCB DLBCL patient samples. In GCB DLBCL, the PTEN status was inversely correlated with activation of the oncogenic PI3K/ protein kinase B (AKT) pathway in both DLBCL cell lines and primary patient samples. Reexpression of PTEN induced cytotox- icity in PTEN-deM-oM-,M-^Acient GCB DLBCL cell line models by inhibiting PI3K/AKT signaling, indicating an addiction to this pathway in this subset of GCB DLBCLs. PI3K/AKT inhibition induced down-regulation of the transcription factor MYC. Reexpression of MYC rescued GCB DLBCL cells from PTEN-induced toxicity, identifying a regulatory mechanism of MYC expression in DLBCL. Finally, pharmacologic PI3K inhibition resulted in toxicity selectively in PTEN-deM-oM-,M-^Acient GCB DLBCL lines. Collectively, our results indicate that PTEN loss deM-oM-,M-^Anes a PI3K/ AKT-dependent GCB DLBCL subtype that is addicted to PI3K and MYC signaling and suggest that pharmacologic inhibition of PI3K might represent a promising therapeutic approach in these lymphomas. This GEO dataset is comprised of a) GEP measurements for 34 primary DLBCL patient samples plus two reference samples, b) 8 paired GEP measurements of the HT DLBCL cell line and c) aCGH measurements for two DLBCL cell lines in addition to previously published cell lines in GSE43272 (i.e., Sample GSM1059798). All of these data were used in the paper cited below.
2013-07-09 | E-GEOD-45495 | biostudies-arrayexpress
Project description:PTEN loss or PI3K/AKT signaling pathway activation correlates with human prostate cancer progression and metastasis. However, in preclinical murine models, deletion of Pten alone fails to mimic the significant metastatic burden that frequently accompanies the end stage of human disease. To identify additional pathway alterations that cooperate with PTEN loss in prostate cancer progression, we surveyed human prostate cancer tissue microarrays and found that the RAS/MAPK pathway is significantly elevated both in primary and metastatic lesions. In an attempt to model this event, we crossed conditional activatable K-rasG12D/WT mice with the prostate conditional Pten deletion model we previously generated. Although RAS activation alone cannot initiate prostate cancer development, it significantly accelerated progression caused by PTEN loss, accompanied by epithelial-to-mesenchymal transition (EMT) and macrometastasis with 100% penitence. A novel stem/progenitor subpopulation with mesenchymal characteristics was isolated from the compound mutant prostates, which was highly metastatic upon orthotopic transplantation. Importantly, inhibition of RAS/MAPK signaling by PD325901, a MEK inhibitor, significantly reduced the metastatic progression initiated from transplanted stem/progenitor cells. Collectively, these data indicate that activation of RAS/MAPK signaling serves as a potentiating second hit to alteration of the PTEN/PI3K/AKT axis and co-targeting both pathways is highly effective in preventing the development of metastatic prostate cancers.
2012-02-28 | GSE34839 | GEO
Project description:The PTEN:P-Rex2 complex is a commonly mutated signaling nodes in metastatic cancer. The dual-specificity phosphatase PTEN canonically functions as a tumour suppressor by hydrolysing PI(3,4,5)P3 to PI(4,5)P2 to inhibit PI3K-AKT signaling. P-Rex2 is a RhoGTPase guanine nucleotide exchange factor activated by both Gβγ and PI(3,4,5)P3 downstream of G protein-coupled receptor and receptor tyrosine kinase signaling. Assembly of the PTEN:P-Rex2 complex inhibits the activity of both proteins, and its dysregulation can drive PI3K-AKT signaling and cell proliferation. However, structural insights into both PTEN:P-Rex2 complex assembly and its dysregulation by cancer-associated mutations remain limited. Here, using crosslinking mass spectrometry and functional studies, we provide mechanistic insights into PTEN:P-Rex2 complex assembly and co-inhibition. PTEN is anchored to P-Rex2 by interactions between the PTEN C-terminal tail PDZ-interacting motif and the second PDZ domain of P-Rex2. This interaction bridges PTEN across the P-Rex2 surface, occluding PI(3,4,5)P3 hydrolysis. Conversely, PTEN both allosterically promotes an autoinhibited P-Rex2 conformation and occludes Gβγ binding. These insights allow us to define a new gain-of-function class of cancer mutations within the PTEN:P-Rex2 interface that uncouples PTEN inhibition of Rac1 signaling. In addition, we observe synergy between PTEN deactivating and P-Rex2 truncation mutations that combine to drive Rac1 activation to a greater extent than either single mutation alone.
2022-08-12 | PXD021126 | Pride
Project description:Although most of the oncogenic phenotypes of PTEN loss have been attributed to AKT activation, AKT alone is not sufficient to induce all of the biological activities associated with PTEN inactivation. We searched for additional PTEN-regulated pathways through gene set enrichment analysis (GSEA) and found that PTEN inactivation causes an enrichment of genes associated with JNK activation. Biochemically, PTEN-null cells exhibit higher JNK activity, and genetic studies demonstrate that JNK functions parallel to and independently of AKT. Furthermore, PTEN deficiency sensitizes cells to JNK inhibition. We also found that negative feedback regulation of PI3K was impaired in PTEN-null cells. These findings implicate JNK in PI3K-driven cancers and demonstrate the utility of GSEA to identify functional pathways using genetically defined systems. Keywords: Genetic modification: PTEN RNAi
2007-06-01 | GSE7562 | GEO
Project description:To perform an integrative profile of human pancreatic cancer (PDAC) to identify prognosis-significant genes and their related pathways. A concordant survival-based whole genome in silico array analysis of DNA copy number, and mRNA & micro RNA (miRNA) expression in 25 early stage PDAC was performed. A novel composite score simultaneously integrated gene expression with regulatory mechanisms to identify the signature genes with the most levels of prognosis-significant evidence. The predominant signaling pathways were determined via a pathway-based approach. Independent patient cohorts (n= 150 and 42) were then used as in vitro validation of the array findings. We find that EGFR, SRC signaling, and PI3K/AKT pathway activation are strongly linked to clinical disease progression. Furthermore, we identify two discrete subsets of pancreatic tumors characterized by either SRC or PI3K/AKT signaling that may dictate variable responses to targeted therapy. 42 human PDAC tumors and 7 non-malignant pancreas samples snap-frozen at the time of surgery were chosen. Representative H&E sections of each were evaluated by a practicing gastrointestinal pathologist to confirm diagnosis and determine relative percentage of malignant cells. Samples with tumor cell content >30% were chosen for final multi-platform analysis (N=25). Human pancreatic samples were profiled on Affymetrix HGU133 Plus 2 arrays per manufacturer's instructions.
2011-10-07 | E-GEOD-32676 | biostudies-arrayexpress
Project description:Diffuse large B-cell lymphoma (DLBCL) represents a heterogeneous diagnostic category with distinct molecular subtypes that can be defined by gene expression profiling. However, even within these defined subtypes, heterogeneity prevails. To further elucidate the pathogenesis of these entities, we determined the expression of the tumor suppressor phosphatase and tensin homolog (PTEN) in 248 primary DLBCL patient samples. These analyses revealed that loss of PTEN was detectable in 55% of germinal center B-cell-like (GCB) DLBCLs, whereas this abnormality was found in only 14% of non-GCB DLBCL patient samples. In GCB DLBCL, the PTEN status was inversely correlated with activation of the oncogenic PI3K/ protein kinase B (AKT) pathway in both DLBCL cell lines and primary patient samples. Re-expression of PTEN induced cytotoxicity in PTEN-deficient GCB DLBCL cell line models by inhibiting PI3K/AKT signaling, indicating an addiction to this pathway in this subset of GCB DLBCLs. PI3K/AKT inhibition induced down-regulation of the transcription factor MYC. Re-expression of MYC rescued GCB DLBCL cells from PTEN-induced toxicity, identifying a regulatory mechanism of MYC expression in DLBCL. Finally, pharmacologic PI3K inhibition resulted in toxicity selectively in PTEN-deficient GCB DLBCL lines. Collectively, our results indicate that PTEN loss defines a PI3K/ AKT-dependent GCB DLBCL subtype that is addicted to PI3K and MYC signaling and suggest that pharmacologic inhibition of PI3K might represent a promising therapeutic approach in these lymphomas.
2013-07-09 | GSE45495 | GEO
Project description:Hyperactivation of the PI3K/AKT pathway is observed in most NSCLCs, promoting proliferation, migration 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 the positive regulator phosphatydil-inositol-3â phosphate kinase (PIK3CA) and/or mutations of AKT1 itself. However, whereas the effects of AKT activation on mRNAs and proteins in the cell are fairly clear, the role of miRNAs as downstream targets of activated PI3K/AKT signalling is still poorly defined so far. To identify miRNAs that are targets of constitutive signalling of PI3K/AKT in lung cancer cells, we performed miRNA profiling of human lung epithelial cells expressing active mutant AKT1 (E17K), active mutant PI3KCA (E545K) or that are silenced for PTEN. We identified 28 differentially expressed miRNAs (8 up-regulated, 20 down-regulated) that were common to BEAS-AKT1-E17K, BEAS-PIK3CA-E545K and BEAS-shPTEN cells. Among the 8 up-regulated miRNAs that were common to all the alterations, the miRNA most consistently up-regulated by activation of the PI3K/AKT pathway in BEAS-2B cells was miR-196a. The results reported here demonstrate that miR-196a acts as oncogene downstream the PI3K/AKT pathway, mediating the proliferative, pro-migratory and tumorigenic activity of this pathway in NSCLC cells by targeting FoxO1 and p27 expression. By adoptive expression of miR-196a in BEAS-2B cells, we demonstrated that miR-196a stimulates anchorage-dependent and -independent proliferation, migration and tumorigenicity in BEAS-2B cells. On the other hand, by use of antimir-196a in NCI-H460 cells to silence the endogenous expression of miR-196a, we demonstrate that miR-196a plays a pivotal role in mediating the stimulation of proliferation, migration and tumorigenicity induced by aberrant activation of PI3K/AKT signalling. Accordingly, we found that miR-196a was significantly overexpressed in human NSCLC-derived cell lines (n=6) and primary lung cancer samples (n=28). Finally, based on predicted binding sites for miR-196a by microRNA analysis software, we found that miR-196a affects protein levels of FoxO1 and p27 in NSCLC cells.
2016-06-13 | E-MTAB-4263 | biostudies-arrayexpress