PI3Kβ controls immune evasion in PTEN-deficient breast tumors
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ABSTRACT:
PROVIDER: PRJNA933635 | ENA |
REPOSITORIES: ENA
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Project description:Loss of the PTEN tumor suppressor is one of the most common oncogenic drivers across all cancer types. PTEN is the major negative regulator of phosphoinositide-3 kinase (PI3K) signaling. Notably, the PI3Kβ isoform has been shown to play an important role in PTEN-deficient tumors, but the mechanisms underlying the importance of PI3Kβ activity remain elusive. Using a syngeneic genetically-engineered mouse (GEM) model of invasive breast cancer driven by concurrent ablation of Pten and Trp53 (p53), we showed that genetic inactivation of PI3Kβ led to a robust anti-tumor immune response that abrogated tumor growth in syngeneic immunocompetent mice, but not in immunodeficient mice. Mechanistically, PI3Kβ inactivation in the PTEN-null setting led to reduced STAT3 signaling and increased expression of immune stimulatory molecules, thereby promoting anti-tumor immune responses. Pharmacological PI3Kβ inhibition also elicited anti-tumor immunity, and synergized with immunotherapy to inhibit tumor growth. Mice with complete responses to the combined treatment displayed immune memory and rejected tumors upon re-challenge. Our findings demonstrate a molecular mechanism linking PTEN loss and STAT3 activation in cancer and suggest that PI3Kβ controls immune escape in PTEN-null tumors, providing a rationale for combining PI3Kβ inhibitors with immunotherapy for the treatment of PTEN-deficient breast cancer.
2023-03-07 | GSE225064 | GEO
Project description:PI3Kβ controls immune evasion in PTEN-deficient breast tumors
| PRJNA933101 | ENA
Project description:We used scRNA-seq to characterize the anti-tumorigenic or pro-tumorigenic immune infiltrate into the tumor microenvironment of TNBC genetically engineered mouse models with PI3Ka versus PI3Kb isoform knockouts.
2023-02-09 | GSE224906 | GEO
Project description:Background: Pericytes regulate vessel stabilization and function and their loss is associated with diseases such as diabetic retinopathy or cancer. Despite their physiological importance, pericyte function and molecular regulation during angiogenesis remain poorly understood. Methods: To decipher the transcriptomic programs of pericytes during angiogenesis, we crossed the Pdgfrb(BAC)-CreERT2 into the RiboTagflox/flox mice. Pericyte morphological changes were assessed in mural cell-specific R26-mTmG reporter mice, in which low doses of tamoxifen allowed labeling of single cell pericytes at high resolution. To study the role of phosphoinositide 3-kinase (PI3K) signaling in pericyte biology during angiogenesis, we used genetic mouse models which allow selective inactivation of PI3Kα and PI3Kβ isoforms and their negative regulator PTEN (phosphate and tensin homologue deleted on chromosome ten, PTEN) in mural cells. Results: At the onset of angiogenesis, pericytes exhibit molecular traits of cell proliferation and activated PI3K signaling, whereas during vascular remodeling pericytes upregulate genes involved in mature pericyte cell function, together with a remarkable decrease in PI3K signaling. Immature pericytes showed stellate shape and high proliferation, and mature pericytes were quiescent and elongated. Unexpectedly, we demonstrate that the PI3Kβ, but not PI3Kα, regulates pericyte proliferation and maturation during vessel formation. Genetic PI3Kβ inactivation in pericytes triggered early pericyte maturation. Conversely, unleashing PI3K signaling by means of PTEN deletion delayed pericyte maturation. Pericyte maturation was necessary to undergo vessel remodeling during angiogenesis. Conclusions: Our results identify new molecular and morphological traits associated to pericyte maturation and uncover PI3Kβ activity as a checkpoint to ensure appropriate vessel formation. In turn, our results may open new therapeutic opportunities to regulate angiogenesis in pathological processes through the manipulation of pericyte PI3Kβ activity.
2020-06-03 | GSE131534 | GEO
Project description:PTEN is a tumor suppressor that is often inactivated in cancer and possesses both lipid and protein phosphatase activities. We report the metabolic regulator PDHK1 (pyruvate dehydrogenase kinase1) is a synthetic-essential gene in PTEN-deficient cancer and normal cells. The predominant mechanism of PDHK1 regulation and dependency is the PTEN protein phosphatase dephosphorylates NFkB activating protein (NKAP) and limits NFkB activation to suppress expression of PDHK1, a NFkB target gene. Loss of the PTEN protein phosphatase upregulates PDHK1 to drive aerobic glycolysis and induce PDHK1 cellular dependence. PTEN-deficient human tumors harbor increased PDHK1, which is a biomarker of decreased patient survival, establishing clinical relevance. This study uncovers a PTEN-regulated signaling pathway and reveals PDHK1 as a potential target in PTEN-deficient cancers.
2019-09-09 | PXD014707 | Pride
Project description:Diffuse large B-cell lymphoma (DLBCL) is a heterogeneous diagnostic category that can be stratified in molecular subtypes based on gene expression profiles and genetic alterations. As roughly one-third of DLBCL patients do not sustainably respond to the current standard chemo-immunotherapy, novel treatment options targeting oncogenic pathways might improve their outcome. Chronic B-cell receptor signaling or PTEN deficiency drive the constitutive activation of the phosphoinositide 3-kinase (PI3K). Since pan-PI3K inhibitors cause severe side effects, we investigated the anti-lymphoma efficacy of the specific PI3Kβ/δ inhibitor AZD8186. We identified a subset of DLBCL models within activated B cell-like (ABC) and germinal center B cell-like (GCB) DLBCL that were sensitive to AZD8186 treatment. On the molecular level, PI3Kβ/δ inhibition decreased the pro-survival nuclear factor kappa-B (NF-κB) and activator protein 1 (AP-1) activity or led to downregulation of the oncogenic transcription factor MYC. In AZD8186-resistant models, we detected a feedback activation of the PI3K/AKT/mTOR pathway following PI3Kβ/δ inhibition. The combined treatment with AZD8186 and the mTOR inhibitor AZD2014 overcame resistance to PI3Kβ/δ inhibition and completely prevented outgrowth of lymphoma cells in vivo in cell line- and patient-derived xenograft mouse models. Collectively, our study reveals that subsets of DLBCLs are addicted to PI3Kβ/δ signaling and thus identifies a previously unappreciated role of the PI3Kβ isoform in DLBCL survival. Furthermore, our data demonstrate that combined targeting of PI3Kβ/δ and mTOR is effective in all major DLBCL subtypes supporting the evaluation of this strategy in a clinical trial setting.
2022-11-07 | GSE212746 | GEO
Project description:Expression data of PTEN deficient PKO cells
| PRJNA975844 | ENA
Project description:Alterations in phosphatidylinositol 3-kinase (PI3K) and in PTEN (phosphatase and tensin homolog), the negative regulator of the PI3K pathway, are found in nearly half of human tumors. As PI3Kβ, the main isoform activated in PTEN-mutant tumors, has kinase-dependent and -independent activities, we compared the effects of depleting vs. drug-inhibiting PI3Kβ kinase activity in a collection of diverse tumor types and in a set of bladder carcinoma cell lines grown as xenografts in mice. PI3Kβ depletion (by intratumor injection of PIK3CB siRNA) induced apoptosis and triggered regression of PTEN-mutant tumors more efficiently than PI3Kβ inhibition. A small proportion of these tumors was resistant to PI3Kβ downregulation; we analyzed what determined resistance in these cases. Using add-back experiments, we show that both PTEN mutation and low E-cadherin expression are necessary for PI3Kβ dependence. In bladder carcinoma, loss of E-cadherin expression coincides with N-cadherin upregulation. We found that PI3Kβ associated with N-cadherin and that PIK3CB depletion selectively disrupted N-cadherin cell adhesions in PTEN-mutant bladder carcinoma. These results support the use of PIK3CB interfering RNA as a therapeutic approach for high-risk bladder cancers that show E-cadherin loss and express mutant PTEN.
| S-EPMC5356644 | biostudies-literature
Project description:T cell-specific deletion of PTEN induces premalignancy in CD4+ CD8+ (DP) immature T cells in the thymus, which progresses to the development of mature CD4+ T cell lymphomas in the lymph nodes and spleen. As part of a screen to identify factors that inhibit progression to malignancy, we compared miRNA expression in premalignant PTEN-deficient DP thymocytes versus wild-type controls. DP thymocytes were collected by cell sorting from three 9-week-old, premalignant T cell-specific PTEN-deficient mice (tPTEN-/-) and three littermate controls. miRNA expression was assessed relative to a reference pool generated from an equal mixture of all samples.
2014-04-12 | E-GEOD-56759 | biostudies-arrayexpress
Project description:T cell-specific deletion of PTEN induces premalignancy in CD4+ CD8+ (DP) immature T cells in the thymus, which progresses to the development of mature CD4+ T cell lymphomas in the lymph nodes and spleen. As part of a screen to identify factors that inhibit progression to malignancy, we compared miRNA expression in premalignant PTEN-deficient DP thymocytes versus wild-type controls.
2014-04-12 | GSE56759 | GEO