We performed mRNA expression profiling of lung tumors from C/L858R, C/T790M, and C/L+T mice and from corresponding normal lung tissue.
Dual targeting of EGFR can overcome a major drug resistance mutation in mouse models of EGFR mutant lung cancer.
No sample metadata fields
View SamplesWe show that NRF2 activation drives hepatocellular carcinoma development in vivo. Moreover, NRF2 undergoes glucose dependent modification called glycation and requires the de-glycating enzyme FN3K to maintain NRF2' oncogenic functions. Overall design: Gene expression analysis in MYC-driven murine HCC with and without NRF2 activation. NRF2 is activated by targeting its negative regulators Keap1 or Cul3 or targeting NRF2 ETGE motif by sgRNA/Cas9 editing.
The Oncogenic Action of NRF2 Depends on De-glycation by Fructosamine-3-Kinase.
Specimen part, Disease, Disease stage, Subject
View SamplesGamma-secretase inhibitors (GSIs), which block the activation of NOTCH receptors, are being tested in the treatment of T-cell acute lymphoblastic leukemia (T-ALL). Thus far, limited antileukemic cytotoxicity and severe gastrointestinal toxicity have restricted the clinical application of these targeted drugs. Here we show that combination therapy with GSIs plus glucocorticoids can improve the antileukemic effects of GSIs and reduce their gut toxicity in vivo. Inhibition of NOTCH1 signaling in glucocorticoid-resistant T-ALL restored glucocorticoid receptor auto-up-regulation and induced apoptotic cell death through induction of BIM expression. Additionally, cotreatment with glucocorticoids induced Ccnd2 upregulation in the gut which protected mice from the intestinal secretory metaplasia typically induced by loss of NOTCH signaling. These results support a role for glucocorticoids plus GSIs in the treatment of glucocorticoid-resistant T-ALL.
Gamma-secretase inhibitors reverse glucocorticoid resistance in T cell acute lymphoblastic leukemia.
Specimen part
View SamplesGlucocorticoids are an essential component of the treatment of lymphoid malignancies and resistance to glucocorticoid therapy constitutes a prominent clinical problem in relapsed and refractory lymphoblastic leukemias. Constitutively active NOTCH signaling is involved in the pathogenesis of over 50% of T-cell lymphoblastic leukemia (T-ALL) which harbor activating mutations in the NOTCH1 gene. Aberrant NOTCH1 signaling has been shown to protect normal thymocytes from glucocorticoid induced cell death. Here we analyzed the interaction of glucocorticoid therapy with inhibition of NOTCH signaling in the treatment of T-ALL. Gamma-secretase inhibitors (GSI), which block the activation of NOTCH receptors, amplified the transcriptional changes induced by glucocorticoid treatment, including glucocorticoid receptor autoinduction and restored sensitivity to dexamethasone in glucocorticoid-resistant T-ALL cells. Apoptosis induction upon inhibition of NOTCH signaling and activation of the glucocorticoid receptor was dependent on transcriptional upregulation of BIM and subsequent activation of the mitochondrial/intrinsic cell death pathway. Finally, we used a mouse xenograft model of T-ALL to demonstrate that combined treatment with dexamethasone and a GSI results in improved antileukemic effects in vivo. These studies provide insight in the mechanisms of glucocorticoid resistance and serve as rationale for the use of glucocorticoid and GSIs in combination in the treatment of T-ALL.
Gamma-secretase inhibitors reverse glucocorticoid resistance in T cell acute lymphoblastic leukemia.
No sample metadata fields
View SamplesWe used microarrays to detail gene expression profile of several follicular lymphoma patient samples with different grades
Frequent disruption of the RB pathway in indolent follicular lymphoma suggests a new combination therapy.
Specimen part
View SamplesGlucocorticoid resistance is a major driver of therapeutic failure in T-cell acute lymphoblastic leukemia (T-ALL). Here we used a systems biology approach, based on the reverse engineering of signaling regulatory networks, which identified the AKT1 kinase as a signaling factor driving glucocorticoid resistance in T-ALL. Indeed, activation of AKT1 in T-ALL lymphoblasts impairs glucocorticoid-induced apoptosis. Mechanistically, AKT1 directly phosphorylates the glucocorticoid receptor NR3C1 protein at position S134 and blocks glucocorticoid-induced NR3C1 translocation to the nucleus. Consistently, inhibition of AKT1 with MK-2206 increases the response of T-ALL cells to glucocorticoid therapy both in T-ALL cell lines and in primary patient samples thus effectively reversing glucocorticoid resistance in vitro and in vivo. These results warrant the clinical testing of ATK1 inhibitors and glucocorticoids, in combination, for the treatment of T-ALL.
Direct reversal of glucocorticoid resistance by AKT inhibition in acute lymphoblastic leukemia.
Specimen part
View SamplesGlucocorticoid resistance is a major driver of therapeutic failure in T-cell acute lymphoblastic leukemia (T-ALL). Here we identify the AKT1 kinase as a signaling factor driving glucocorticoid resistance in T-ALL. Mechanistically, AKT1 directly phosphorylates the glucocorticoid receptor NR3C1 protein and blocks glucocorticoid-induced NR3C1 transcription by inhibiting glucocorticoid-induced NT3C1 translocation to the nucleus. Consistently, pharmacologic inhibition of AKT1 increases the response of T-ALL cells to glucocorticoid therapy and effectively reverses glucocorticoid resistance in vitro and in vivo. These results warrant the clinical testing of AKT1 inhibitors and glucocorticoids in combination for the treatment of T-ALL.
Direct reversal of glucocorticoid resistance by AKT inhibition in acute lymphoblastic leukemia.
Cell line
View SamplesSome cancers evade targeted therapies through a mechanism known as lineage plasticity, whereby tumor cells acquire phenotypic characteristics of a cell lineage whose survival no longer depends on the drug target. Here we show, using in vitro and in vivo prostate cancer models, that these tumors can develop resistance to the antiandrogen drug enzalutamide by a phenotypic shift from androgen receptor (AR) dependent luminal epithelial cells to AR independent basal-like cells. This lineage plasticity is enabled by loss of TP53 and RB1 function, is mediated by increased expression of the reprogramming transcription factor SOX2 and can be reversed by restoring TP53 and RB1 function or by inhibiting SOX2 expression. Thus, mutations in tumor suppressor genes can create a state of increased cellular plasticity that, when challenged with antiandrogen therapy, promotes resistance through lineage switching. Overall design: LNCaP/AR prostate cell line was transduced with shNT or shTP53:RB1 hairpins and then RNA was harvested from these cell lines for gene epxression analysis.
SOX2 promotes lineage plasticity and antiandrogen resistance in TP53- and RB1-deficient prostate cancer.
Cell line, Subject
View SamplesThe translational control of oncoprotein expression is implicated in many cancers. Here we report an eIF4A/DDX2 RNA helicase-dependent mechanism of translational control that contributes to oncogenesis and underlies the anticancer effects of Silvestrol and related compounds. For example, eIF4A promotes T-ALL development in vivo and is required for leukaemia maintenance. Accordingly, inhibition of eIF4A with Silvestrol has powerful therapeutic effects in vitro and in vivo. We use transcriptome-scale ribosome footprinting to identify the hallmarks of eIF4A-dependent transcripts. These include 5'UTR sequences such as the 12-mer guanine quartet (CGG)4 motif that can form RNA G-quadruplex structures. Notably, among the most eIF4A-dependent and Silvestrol-sensitive transcripts are a number of oncogenes, super-enhancer associated transcription factors, and epigenetic regulators. Hence, the 5'UTRs of selected cancer genes harbour a targetable requirement for the eIF4A RNA helicase. Overall design: Comparison of ribosome-protected RNA for drug treated and DMSO treated KOPT-K1 cell, two replicates of ribosome-protected RNA sequencing and three replicates of RNA-seq.
RNA G-quadruplexes cause eIF4A-dependent oncogene translation in cancer.
No sample metadata fields
View SamplesIn acute myeloid leukemia, chemotherapy resistance remains prevalent and poorly understood. Using functional proteomics of patient AML specimens, we identified MEF2C S222 phosphorylation as a specific marker of primary chemoresistance. We found that transgenic Mef2cS222A/S222A mice engineered to block MEF2C phosphorylation exhibited normal hematopoiesis, but were resistant to leukemogenesis induced by MLL-AF9. MEF2C phosphorylation was required for leukemia stem cell maintenance, induced by MARK kinases in cells, and blocked by selective MARK inhibitor MRT199665, which caused apoptosis of MEF2C-activated human AML cell lines and primary patient specimens, but not those lacking MEF2C. These findings identify signaling-dependent dysregulation of transcription factor control as a determinant of therapy response in AML, with immediate potential for improved diagnosis and therapy for this disease. Overall design: RNA-sequencing of human leukemia cell line with induction of wildtype or mutant MEF2C.
MEF2C Phosphorylation Is Required for Chemotherapy Resistance in Acute Myeloid Leukemia.
Specimen part, Cell line, Treatment, Subject
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