PI3K inhibition activates SGK1 via a feedback loop to promote chromatin-based regulation of ER-dependent gene expression
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE119522 | GEO | 2019/04/02
REPOSITORIES: GEO
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Project description:Activating mutations in PIK3CA, the gene encoding PI3Kα, are frequently found in estrogen receptor (ER+) breast cancer and the combination of the PI3K inhibitor alpelisib with the anti-ER agent fulvestrant is approved for therapy. We have uncovered a key role for the chromatin modifier KMT2D in regulating the ER-PI3K crosstalk. PI3Kα effectors, AKT and SGK, negatively regulate KMT2D through S1331 phosphorylation. When PI3K is inhibited, this regulatory event is lost, leading to increased chromatin recruitment of KMT2D and an upregulation of ER-dependent transcription. Here we discovered a previously undescribed methylation site on KMT2D, at K1330 directly adjacent to S1331, catalyzed by the lysine methyltransferase SMYD2. SMYD2 loss attenuates alpelisib-induced KMT2D chromatin binding. Accordingly, loss of SMYD2 abrogates alpelisib-induced changes in gene expression, including ER-dependent transcription. Knockdown or pharmacological inhibition of SMYD2 sensitizes breast cancer cells, patient-derived organoids, and tumors to PI3K/AKT inhibition and endocrine therapy in part through KMT2D K1330 methylation. Methyl dead knock-in clones of KMT2D phenocopy many of the effects of SMYD2 inhibition on cell and tumor growth, drug response, and transcriptional output. Together, our findings uncover a regulatory cross-talk between posttranslational modifications that plays an important role in fine-tuning the functions of KMT2D at the chromatin. This provides a rationale for epigenetic therapy using SMYD2 inhibitors in combination with PI3Kα/AKT inhibitors for the treatment of ER+/PIK3CA mutant breast cancer.
2024-05-04 | GSE255295 | GEO
Project description:Activating mutations in PIK3CA, the gene encoding PI3Kα, are frequently found in estrogen receptor (ER+) breast cancer and the combination of the PI3K inhibitor alpelisib with the anti-ER agent fulvestrant is approved for therapy. We have uncovered a key role for the chromatin modifier KMT2D in regulating the ER-PI3K crosstalk. PI3Kα effectors, AKT and SGK, negatively regulate KMT2D through S1331 phosphorylation. When PI3K is inhibited, this regulatory event is lost, leading to increased chromatin recruitment of KMT2D and an upregulation of ER-dependent transcription. Here we discovered a previously undescribed methylation site on KMT2D, at K1330 directly adjacent to S1331, catalyzed by the lysine methyltransferase SMYD2. SMYD2 loss attenuates alpelisib-induced KMT2D chromatin binding. Accordingly, loss of SMYD2 abrogates alpelisib-induced changes in gene expression, including ER-dependent transcription. Knockdown or pharmacological inhibition of SMYD2 sensitizes breast cancer cells, patient-derived organoids, and tumors to PI3K/AKT inhibition and endocrine therapy in part through KMT2D K1330 methylation. Methyl dead knock-in clones of KMT2D phenocopy many of the effects of SMYD2 inhibition on cell and tumor growth, drug response, and transcriptional output. Together, our findings uncover a regulatory cross-talk between posttranslational modifications that plays an important role in fine-tuning the functions of KMT2D at the chromatin. This provides a rationale for epigenetic therapy using SMYD2 inhibitors in combination with PI3Kα/AKT inhibitors for the treatment of ER+/PIK3CA mutant breast cancer.
2024-05-04 | GSE253958 | GEO
Project description:Activating mutations in PIK3CA, the gene encoding PI3Kα, are frequently found in estrogen receptor (ER+) breast cancer and the combination of the PI3K inhibitor alpelisib with the anti-ER agent fulvestrant is approved for therapy. We have uncovered a key role for the chromatin modifier KMT2D in regulating the ER-PI3K crosstalk. PI3Kα effectors, AKT and SGK, negatively regulate KMT2D through S1331 phosphorylation. When PI3K is inhibited, this regulatory event is lost, leading to increased chromatin recruitment of KMT2D and an upregulation of ER-dependent transcription. Here we discovered a previously undescribed methylation site on KMT2D, at K1330 directly adjacent to S1331, catalyzed by the lysine methyltransferase SMYD2. SMYD2 loss attenuates alpelisib-induced KMT2D chromatin binding. Accordingly, loss of SMYD2 abrogates alpelisib-induced changes in gene expression, including ER-dependent transcription. Knockdown or pharmacological inhibition of SMYD2 sensitizes breast cancer cells, patient-derived organoids, and tumors to PI3K/AKT inhibition and endocrine therapy in part through KMT2D K1330 methylation. Methyl dead knock-in clones of KMT2D phenocopy many of the effects of SMYD2 inhibition on cell and tumor growth, drug response, and transcriptional output. Together, our findings uncover a regulatory cross-talk between posttranslational modifications that plays an important role in fine-tuning the functions of KMT2D at the chromatin. This provides a rationale for epigenetic therapy using SMYD2 inhibitors in combination with PI3Kα/AKT inhibitors for the treatment of ER+/PIK3CA mutant breast cancer.
2024-05-04 | GSE253957 | GEO
Project description:The high frequency of aberrant PI3K pathway activation in hormone receptor-positive (HR+) breast cancer has led to the development, clinical testing, and approval of the p110a-selective PI3K inhibitor alpelisib. The limited clinical efficacy of alpelisib and other PI3K inhibitors is partially attributed to the functional antagonism between PI3K and estrogen receptor (ER) signaling, which is mitigated via combined PI3K inhibition and endocrine therapy. We and others have previously demonstrated chromatin-associated mechanisms by which PI3K supports cancer development and antagonizes ER signaling through the modulation of the H3K4 methylation axis; inhibition of KDM5A promoter H3K4 demethylation and KMT2D/MLL4-directed enhancer H3K4 methylation. Here we show that inhibition of the H3K4 histone methyltransferase MLL1 in combination with PI3K inhibition impairs HR+ breast cancer clonogenicity and cell proliferation. While combined PI3K/MLL1 inhibition reduces PI3K/AKT signaling and H3K4 methylation, MLL1 inhibition increases PI3K/AKT signaling and dysregulates the expression of processes that lead to AKT activation. These data reveal a feedback loop between MLL1 and AKT whereby MLL1 inhibition reactivates AKT. We show that combined PI3K and MLL1 inhibition synergizes to cause cell death in in vitro and in vivo models of HR+ breast cancer, which is enhanced by the additional genetic ablation of the H3K4 methyltransferase and AKT target KMT2D/MLL4. Together, our data provide evidence of a feedback mechanism connecting histone methylation with AKT and may support the preclinical development and testing of pan-MLL inhibitors.
2022-10-01 | GSE214331 | GEO
Project description:The high frequency of aberrant PI3K pathway activation in hormone receptor-positive (HR+) breast cancer has led to the development, clinical testing, and approval of the p110a-selective PI3K inhibitor alpelisib. The limited clinical efficacy of alpelisib and other PI3K inhibitors is partially attributed to the functional antagonism between PI3K and estrogen receptor (ER) signaling, which is mitigated via combined PI3K inhibition and endocrine therapy. We and others have previously demonstrated chromatin-associated mechanisms by which PI3K supports cancer development and antagonizes ER signaling through the modulation of the H3K4 methylation axis; inhibition of KDM5A promoter H3K4 demethylation and KMT2D/MLL4-directed enhancer H3K4 methylation. Here we show that inhibition of the H3K4 histone methyltransferase MLL1 in combination with PI3K inhibition impairs HR+ breast cancer clonogenicity and cell proliferation. While combined PI3K/MLL1 inhibition reduces PI3K/AKT signaling and H3K4 methylation, MLL1 inhibition increases PI3K/AKT signaling and dysregulates the expression of processes that lead to AKT activation. These data reveal a feedback loop between MLL1 and AKT whereby MLL1 inhibition reactivates AKT. We show that combined PI3K and MLL1 inhibition synergizes to cause cell death in in vitro and in vivo models of HR+ breast cancer, which is enhanced by the additional genetic ablation of the H3K4 methyltransferase and AKT target KMT2D/MLL4. Together, our data provide evidence of a feedback mechanism connecting histone methylation with AKT and may support the preclinical development and testing of pan-MLL inhibitors.
2022-10-01 | GSE214329 | GEO
Project description:PI3K inhibition activates SGK1 via a feedback loop to promote chromatin-based regulation of ER-dependent gene expression
| PRJNA489456 | ENA
Project description:Skeletal muscle is known to adapt dynamically to changes in workload by regulatory processes of the phosphatidylinositide 3-kinase (PI3K)/Akt pathway. We performed a global quantitative phosphoproteomics analysis of contracting mouse C2 myotubes treated with insulin growth factor 1 (IGF-1) or LY294002 to activate or inhibit PI3K/Akt signaling, respectively. Among the significantly regulated phosphopeptides we identified the novel extended basophilic motif RxRxxp[S/T]xxp[S] to be enriched in the set of down-regulated phosphopeptides following inhibition of PI3K/Akt signaling. Using literature-based text mining we identified the kinases Akt, serum and glucocorticoid-regulated kinase 1 (SGK1) and p70S6 kinase to be potentially involved in the phosphorylation of the first serine in the RxRxxp[S/T]xxp[S] motif, whereas no kinase targeting the serine in the +3 position was revealed. In the signaling adapter protein filamin c (FLNc) we found this novel motif in immunoglobulin (Ig)-like domain 20 which is involved in various protein interactions. Through in vitro and in cellulo kinase assays we identified Akt and protein kinase C alpha as the responsible kinases phosphorylating FLNc in this motif at the first and the second serine, respectively.
2020-06-30 | PXD009228 | Pride
Project description:Phosphoinositide-3-kinase/protein-kinaseB/mammalian target of rapamycin (PI3K/AKT/mTOR) signalling plays an important role in breast cancer (BC). Its interaction with estrogen receptor (ER) signalling becomes more complex and inter-dependent with acquired endocrine resistance. Targeting mTOR combined with endocrine therapy has shown clinical utility, however, a negative feedback-loop exists downstream of PI3K/AKT/mTOR. Direct blockade of AKT together with endocrine therapy may improve BC treatment. AZD5363, a novel pan-AKT kinase catalytic inhibitor, was examined in a panel of ER+ BC cell lines (MCF7, HCC1428, T47D, ZR75.1) adapted to long-term-estrogen-deprivation (LTED) or tamoxifen (TamR). AZD5363 caused a dose-dependent decrease in proliferation in all cell lines tested (GI50<500nM) except HCC1428 and HCC1428-LTED. T47D-LTED and ZR75-LTED were the most sensitive of the lines (GI50~100nM). AZD5363 re-sensitised TamR cells to tamoxifen and acted synergistically with fulvestrant. AZD5363 decreased p-AKT/mTOR targets leading to a reduction in ERα-mediated transcription in a context specific manner and concomitant decrease in recruitment of ER and CREB-binding protein (CBP) to estrogen-response-elements located on the TFF1, PGR and GREB1 promoters. Furthermore, AZD5363 reduced expression of cell-cycle-regulatory proteins. Global gene expression highlighted ERBB2-ERBB3, ERK5 and IGF1 signaling pathways driven by MYC as potential feedback-loops. Combined treatment with AZD5363 and fulvestrant showed synergy in an ER+ patient derived xenograft and delayed tumour progression post-cessation of therapy. These data support the combination of AZD5363 with fulvestrant as a potential therapy for BC that is sensitive or resistant to E-deprivation or tamoxifen and that activated AKT is a determinant of response, supporting the need for clinical evaluation. Cell lines were treated in biological triplicates in the absence of estrogen with or without AZD5363 for 24hours in order to identify gene changes associated with perturbation of AKT signalling
2015-06-29 | E-GEOD-69893 | biostudies-arrayexpress
Project description:Activating mutations of PIK3CA are the most frequent genomic alterations in estrogen receptor (ER)-positive breast tumors and selective PI3Kα inhibitors are in clinical development. The activity of these agents, however, is not homogenous and only a fraction of patients bearing PIK3CA-mutant ER-positive tumors benefit from single agent administration. Searching for mechanisms of resistance, we observed that suppression of PI3K signaling with different agents results in induction of ER-dependent transcriptional activity as demonstrated by changes in expression in genes containing ER binding sites, enhanced ER transcription and increased occupancy by the ER of promoter regions of upregulated genes. Furthermore, expression of ESR1 mRNA and ER protein levels themselves were also increased upon PI3K inhibition. These changes in gene expression were confirmed in vivo in xenograft and patient derived models and in tumors from patients undergoing treatment with the PI3Kα inhibitor BYL719. The observed effects on transcription were enhanced by the addition of estradiol and suppressed by the anti-ER therapies fulvestrant and tamoxifen. Fulvestrant markedly sensitized ER-positive tumors to PI3Kα inhibition. We propose that increased ER transcriptional activity may be a compensatory mechanism that limits the activity of PI3K inhibitors and that combined PI3K and ER inhibition is a rational approach to target these tumors. The aim of our study was to explore the mechanism by which combination of PI3K pathway inhibitors and estrogen receptor function blockade results in superior antitumor activity. We aimed to evaluate whether changes in ER function were influencing the clinical response to anti-PI3K therapy in ER-positive breast tumors that harbor PI3K pathway activation. For this purpose, we planned to use various specific PI3K inhibitors, namely: BYL719 (p110α specific catalytic inhibitor), GDC0941 (pan-PI3K inhibitor), GDC0032 and BAY80-6946 (p110sparing PI3K inhibitors) in a panel of ER-positive breast cancer cell lines and xenografts that harbor PIK3CA activating mutations. We also used MK2206 (pan-AKT allosteric inhibitor) to inhibit the PI3K pathway in ER-positive cell lines which activate this pathway through PTEN loss. Finally, in order to evaluate the role of ER up-regulation as a pro-survival signal in our in vitro and in vivo models, we planned to use the selective ER modulator 4-hydroxy-tamoxifen (4-OHT) and degrader fulvestrant. For the in vivo experiments, the number of animals in each group was calculated to measure a 25% difference between the means of placebo and treatment groups with a power of 80% and a p value of 0.01. Host mice carrying xenografts were randomly and equally assigned to either control or treatment groups. Animal experiments were conducted in a controlled and non-blinded manner. Moreover, we evaluated by means of RNAseq gene expression changes breast cancer patients that underwent BYL719 based therapy to validate our in vitro findings in terms of ER expression. In vitro experiments were performed at least two times and at least in triplicate for each replica.
2015-04-29 | E-GEOD-64033 | biostudies-arrayexpress
Project description:Padala2017- ERK, PI3K/Akt and Wnt signalling
network (PI3K mutated)
Crosstalk model of the ERK, Wnt and Akt
signalling pathways with mutated PI3K.
This model is described in the article:
Cancerous perturbations
within the ERK, PI3K/Akt, and Wnt/?-catenin signaling network
constitutively activate inter-pathway positive feedback
loops.
Padala RR, Karnawat R, Viswanathan
SB, Thakkar AV, Das AB.
Mol Biosyst 2017 May; 13(5):
830-840
Abstract:
Perturbations in molecular signaling pathways are a result
of genetic or epigenetic alterations, which may lead to
malignant transformation of cells. Despite cellular robustness,
specific genetic or epigenetic changes of any gene can trigger
a cascade of failures, which result in the malfunctioning of
cell signaling pathways and lead to cancer phenotypes. The
extent of cellular robustness has a link with the architecture
of the network such as feedback and feedforward loops.
Perturbation in components within feedback loops causes a
transition from a regulated to a persistently activated state
and results in uncontrolled cell growth. This work represents
the mathematical and quantitative modeling of ERK, PI3K/Akt,
and Wnt/?-catenin signaling crosstalk to show the dynamics of
signaling responses during genetic and epigenetic changes in
cancer. ERK, PI3K/Akt, and Wnt/?-catenin signaling crosstalk
networks include both intra and inter-pathway feedback loops
which function in a controlled fashion in a healthy cell. Our
results show that cancerous perturbations of components such as
EGFR, Ras, B-Raf, PTEN, and components of the destruction
complex cause extreme fragility in the network and
constitutively activate inter-pathway positive feedback loops.
We observed that the aberrant signaling response due to the
failure of specific network components is transmitted
throughout the network via crosstalk, generating an additive
effect on cancer growth and proliferation.
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2024-09-02 | BIOMD0000000652 | BioModels