Lipid addiction via Fatty Acid Synthase activates PI3K signaling in B cell non-Hodgkin’s Lymphoma (bNHL) [SUDHL2, SUHDL10, and Raji]
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ABSTRACT: Dysregulated lipid metabolism is an oncogenic mechanism that leads to increased de novo fatty acid biosynthesis via elevated expression of fatty acid synthase (FASN) in cancer. FASN catalyzes biosynthesis of (C16) palmitic acid by using Acetyl CoA, malonyl CoA and NADPH as substrates. Palmitic acid and its derivatives participate as signaling lipids andinvolved in the regulation of receptor functions associated with many biological processes. and furtherThis includes contribute formation of cell structures, and all these processes which are essential for both normal and malignant cell growth and proliferation. In this study, we investigated the biological impact of FASN inhibition in B cell Non Hodgkin Lymphoma (bNHL) cells using FASN inhibitors Cerulenin and other novel agents (TVB3166, TVB3567). Inhibition of FASN resulted in a dose dependent increase in cell death and apoptosis in the bNHL and primary tumor cells. Transcriptomic and comprehensive systems biology analysis of cerulenin, TVB3166 or TVB3567 treated bNHL cells revealed conserved activation of (TNF) immune and PI3K signaling, and inhibition of cell cycle pathways as prominent responses to FASN inhibition. Cell fractionation and western blot analysis of cCerulenin treated cells showed translocation of TNF receptor adaptor proteins (TRAF2 and RIP), docking of AKT and PI3K/p110 subunits to cell membrane and activation of PI3K/AKT pathways by phosphorylation in SUDHL2 and SUDHL4 bNHL cells, while these mechanisms were constitutively active in cerulenin treated SUDHL10 bNHL cells. Disruption of lipid raft formation by methyl β cyclodextrin inhibited PI3K signaling and downregulated FASN expression in SUDHL10 cells. Subsequently, we observed that combination of FASN (cerulenin) and PI3K (Buparlisib) inhibitors resulted in synergistic cell death in bNHL cell lines and increased apoptosis accompanied with down-regulation of FASN expression in bNHL cell lines and primary cells, implicating the importance of PI3K in the regulation of lipid metabolism. Further mass spectrometric evaluation of cerulenin and Buparlisib treated DLBCL cells fed with C14C glucose, synergistically decreased the biosynthesis of palmitic acid and its derivatives compared to single agent treatments. Our conclusions from these investigations suggest that simultaneous blocking of PI3K and FASN is likely to exert stronger inhibition of lipid metabolism and enhance cell death in lymphoma.
Project description:Dysregulated lipid metabolism is an oncogenic mechanism that leads to increased de novo fatty acid biosynthesis via elevated expression of fatty acid synthase (FASN) in cancer. FASN catalyzes biosynthesis of (C16) palmitic acid by using Acetyl CoA, malonyl CoA and NADPH as substrates. Palmitic acid and its derivatives participate as signaling lipids andinvolved in the regulation of receptor functions associated with many biological processes. and furtherThis includes contribute formation of cell structures, and all these processes which are essential for both normal and malignant cell growth and proliferation. In this study, we investigated the biological impact of FASN inhibition in B cell Non Hodgkin Lymphoma (bNHL) cells using FASN inhibitors Cerulenin and other novel agents (TVB3166, TVB3567). Inhibition of FASN resulted in a dose dependent increase in cell death and apoptosis in the bNHL and primary tumor cells. Transcriptomic and comprehensive systems biology analysis of cerulenin, TVB3166 or TVB3567 treated bNHL cells revealed conserved activation of (TNF) immune and PI3K signaling, and inhibition of cell cycle pathways as prominent responses to FASN inhibition. Cell fractionation and western blot analysis of cCerulenin treated cells showed translocation of TNF receptor adaptor proteins (TRAF2 and RIP), docking of AKT and PI3K/p110 subunits to cell membrane and activation of PI3K/AKT pathways by phosphorylation in SUDHL2 and SUDHL4 bNHL cells, while these mechanisms were constitutively active in cerulenin treated SUDHL10 bNHL cells. Disruption of lipid raft formation by methyl β cyclodextrin inhibited PI3K signaling and downregulated FASN expression in SUDHL10 cells. Subsequently, we observed that combination of FASN (cerulenin) and PI3K (Buparlisib) inhibitors resulted in synergistic cell death in bNHL cell lines and increased apoptosis accompanied with down-regulation of FASN expression in bNHL cell lines and primary cells, implicating the importance of PI3K in the regulation of lipid metabolism. Further mass spectrometric evaluation of cerulenin and Buparlisib treated DLBCL cells fed with C14C glucose, synergistically decreased the biosynthesis of palmitic acid and its derivatives compared to single agent treatments. Our conclusions from these investigations suggest that simultaneous blocking of PI3K and FASN is likely to exert stronger inhibition of lipid metabolism and enhance cell death in lymphoma.
Project description:Dysregulated lipid metabolism is an oncogenic mechanism that leads to increased de novo fatty acid biosynthesis via elevated expression of fatty acid synthase (FASN) in cancer. FASN catalyzes biosynthesis of (C16) palmitic acid by using Acetyl CoA, malonyl CoA and NADPH as substrates. Palmitic acid and its derivatives participate as signaling lipids andinvolved in the regulation of receptor functions associated with many biological processes. and furtherThis includes contribute formation of cell structures, and all these processes which are essential for both normal and malignant cell growth and proliferation. In this study, we investigated the biological impact of FASN inhibition in B cell Non Hodgkin Lymphoma (bNHL) cells using FASN inhibitors Cerulenin and other novel agents (TVB3166, TVB3567). Inhibition of FASN resulted in a dose dependent increase in cell death and apoptosis in the bNHL and primary tumor cells. Transcriptomic and comprehensive systems biology analysis of cerulenin, TVB3166 or TVB3567 treated bNHL cells revealed conserved activation of (TNF) immune and PI3K signaling, and inhibition of cell cycle pathways as prominent responses to FASN inhibition. Cell fractionation and western blot analysis of cCerulenin treated cells showed translocation of TNF receptor adaptor proteins (TRAF2 and RIP), docking of AKT and PI3K/p110 subunits to cell membrane and activation of PI3K/AKT pathways by phosphorylation in SUDHL2 and SUDHL4 bNHL cells, while these mechanisms were constitutively active in cerulenin treated SUDHL10 bNHL cells. Disruption of lipid raft formation by methyl β cyclodextrin inhibited PI3K signaling and downregulated FASN expression in SUDHL10 cells. Subsequently, we observed that combination of FASN (cerulenin) and PI3K (Buparlisib) inhibitors resulted in synergistic cell death in bNHL cell lines and increased apoptosis accompanied with down-regulation of FASN expression in bNHL cell lines and primary cells, implicating the importance of PI3K in the regulation of lipid metabolism. Further mass spectrometric evaluation of cerulenin and Buparlisib treated DLBCL cells fed with C14C glucose, synergistically decreased the biosynthesis of palmitic acid and its derivatives compared to single agent treatments. Our conclusions from these investigations suggest that simultaneous blocking of PI3K and FASN is likely to exert stronger inhibition of lipid metabolism and enhance cell death in lymphoma.
Project description:TVB-3166, an orally available, reversible, potent, and selective FASN inhibitors, was used to investigate FASN as a cancer therapeutic target. FASN inhibition with TVB-3166 induces apoptosis, inhibits anchorage-independent cell growth under lipid-rich conditions, and inhibits in vivo xenograft tumor growth. The effects are dose dependent between 20-200 nM TVB-3166, which agrees with the IC50 value in biochemical FASN and cellular palmitate synthesis assays. Studies to understand the mechanism of action show that FASN inhibition disrupts lipid raft architecture, inhibits biological pathways such as lipid biosynthesis, PI3K-AKT-mTOR and β-catenin signal transduction, and inhibits expression of downstream oncogenic effectors such as c-Myc. These effects are observed in tumor cells but not fibroblast or endothelial cell types. Our results show that FASN inhibition has anti-tumor activities in biologically diverse preclinical tumor models, including those expressing mutant K-Ras, ErbB2, c-Met, and PTEN. The reported findings inform ongoing studies to link specific mechanisms of action with defined tumor types and advance the discovery of biomarkers to support development of FASN inhibitors as novel cancer therapeutics.
Project description:Phosphoinositide 3-kinase (PI3K) signaling activation is frequently observed in triple negative breast cancer, however, PI3K inhibitors have shown limited clinical activity. To investigate resistance mechanisms, we performed global transcriptome, proteome, phosphoproteome and kinome analysis of a panel of triple negative breast cancer patient derived xenograft models with varying responsiveness to buparlisib, a pan-PI3K inhibitor, for differentially expressed baseline and post-treatment biomarkers. Resistance was associated with incomplete inhibition of PI3K and upregulated MAPK/MEK signaling in response to buparlisib. Outlier phosphoproteome and kinome analyses identified additional candidates in association with buparlisib resistance, including NEK9 and MAP2K4. Knockdown of NEK9 or MAPK2K4 reduced both baseline and feedback MAPK/MEK signaling and enhanced buparlisib efficacy in vitro. Interestingly, we show that a complex ins/del in PIK3CA led to a change in buparlisib response in a NEK9/MAP2K4 dependent manner. In summary, our study indicates a role for NEK9 and MAP2K4 in mediating buparlisib resistance and demonstrates the value of unbiased global analyses in uncovering resistance mechanisms to targeted therapy.
Project description:Acute myeloid leukemia (AML) is a rare hematological malignancy with a poor prog-nosis. Activating c-Kit (CD117) mutations occur in 5% of de novo AML and 30% of core-binding factor (CBF) AML, leading to worse clinical outcomes. Posttranslational modifications, particularly with myristic and palmitic acid, are crucial for various cellular processes, including membrane organization, signal transduction, and apoptosis regu-lation. However, most research has focused on solid tumors, with limited understanding of these mechanisms in AML. Fatty acid synthase (FASN), a key palmito-yl-acyltransferase, regulates the subcellular localization, trafficking, and degradation of target proteins, such as H-Ras, N-Ras, and FLT3-ITDmut receptors in AML. Methods: In this study, we investigated the role of FASN in two c-Kit-N822K-mutated AML cell lines using FASN knockdown via shRNA and the FASN inhibitor TVB-3166. Functional im-plications, including cell proliferation, were assessed through Western blotting, mass spectrometry, and PamGene. Results: FASN inhibition led to an increased phosphory-lation of c-Kit (p-c-Kit), Lyn kinase (pLyn), MAP kinase (pMAPK), and S6 kinase (pS6). Furthermore, we observed sustained high expression of Gli1 in Kasumi1 cells following FASN inhibition, which is well known to be mediated by the upregulation of pS6. Conclusions: The combination of TVB-3166 and the Gli inhibitor GANT61 resulted in a significant reduction in the survival of Kasumi1 cells.
Project description:We found that palmitic acid inhibits proliferation and cell death of Tregs in the skin. The goal of this study is to investigate how Palmitic acid drives lipid toxicity in skin Tregs
Project description:Abstract:AP-2α (encoded by TFAP2A) functions as a tumor suppressor and influences response to therapy in several cancer types. We aimed to characterize regulation of the transcriptome by AP-2α in colon cancer. Results: Knockout of TFAP2A induced significant alterations in the transcriptome including repression of TGM2, identified as a primary gene target of AP-2α. Loss of AP-2α delayed progression through S-phase into G2/M and decreased phosphorylation of AKT, effects that were mediated through regulation of TGM2. Buparlisib (BKM120) repressed in vitro invasiveness of HCT116 and LS-180; however, loss of AP-2α induced resistance to Buparlisib. Similarly, Buparlisib repressed PHH3 and growth of tumor xenografts and increased overall survival of tumor-bearing mice, whereas, loss of AP-2α induced resistance to the effect of PI3K inhibition. Conclusion: Loss of AP-2α in colon cancer leads to prolonged S-phase through altered activation of AKT leading to resistance to the PI3K inhibitor, Buparlisib. The findings demonstrate an important role for AP-2α in regulating progression through the cell cycle and indicates that AP-2α is a marker for response to PI3K inhibitors.
Project description:Abstract:AP-2α (encoded by TFAP2A) functions as a tumor suppressor and influences response to therapy in several cancer types. We aimed to characterize regulation of the transcriptome by AP-2α in colon cancer. Results: Knockout of TFAP2A induced significant alterations in the transcriptome including repression of TGM2, identified as a primary gene target of AP-2α. Loss of AP-2α delayed progression through S-phase into G2/M and decreased phosphorylation of AKT, effects that were mediated through regulation of TGM2. Buparlisib (BKM120) repressed in vitro invasiveness of HCT116 and LS-180; however, loss of AP-2α induced resistance to Buparlisib. Similarly, Buparlisib repressed PHH3 and growth of tumor xenografts and increased overall survival of tumor-bearing mice, whereas, loss of AP-2α induced resistance to the effect of PI3K inhibition. Conclusion: Loss of AP-2α in colon cancer leads to prolonged S-phase through altered activation of AKT leading to resistance to the PI3K inhibitor, Buparlisib. The findings demonstrate an important role for AP-2α in regulating progression through the cell cycle and indicates that AP-2α is a marker for response to PI3K inhibitors.