Project description:The unfolded protein response (UPR) maintains endoplasmic reticulum (ER) homeostasis by sensing protein-folding stress and orchestrating cellular adaptation via the ER-transmembrane proteins IRE1, PERK and ATF6. Malignant cells can co-opt UPR signaling by IRE1 and PERK to sustain tumor growth; however, the importance of ATF6 in cancer remains poorly deciphered. We observed elevated ATF6 transcriptional activity in several cancers including colorectal carcinoma (CRC). Genetic silencing or small molecule inhibition of ATF6 blocked cell cycle progression and reduced viability of several human CRC cell lines in vitro and disrupted tumor progression in vivo. Unexpectedly, ATF6 interference also disabled Myc and Wnt signaling and reduced stemness. ATF6 inhibition attenuated growth of organoids derived from malignant but not normal human intestinal tissue, reducing Wnt-pathway activity and driving cellular differentiation. Wnt-surrogate agonism rescued the growth inhibitory phenotype of ATF6 interference. Our findings identify ATF6 as an unexpected facilitator of oncogenic Wnt signaling in CRC.
Project description:The p160 Steroid Receptor Coactivators SRC-1, SRC-2, and SRC-3 are critical components of the AR transcriptional complex and are frequently upregulated in prostate cancer (PC). We showed that inhibition of the SRCs via a small molecule inhibitor significantly diminishes AR signaling output, expression of CRPC-associated transcripts and proliferation of CRPC cells both in vitro and in vivo.
Project description:The p160 Steroid Receptor Coactivators SRC-1, SRC-2, and SRC-3 are critical components of the AR transcriptional complex and are frequently upregulated in prostate cancer (PC). We showed that inhibition of the SRCs via a small molecule inhibitor significantly diminishes AR signaling output, expression of CRPC-associated transcripts and proliferation of CRPC cells both in vitro and in vivo.
Project description:Resistance to androgen deprivation therapies and increased androgen receptor (AR) activity are major drivers of castration-resistant prostate cancer (CRPC). Prior work has focused on targeting AR directly; however, the identification and targeting of co-activators of AR signaling remains an underexplored area. Here we demonstrate that the MLL (mixed-lineage leukemia) complex, a well-known contributor in MLL-fusion-positive leukemia, acts as a co-activator of AR signaling. AR interacts with the MLL complex via its subunit, menin. Small molecule inhibition of the menin-MLL interaction blocks AR signaling and inhibits tumor growth in vivo. Furthermore, we find that menin is up-regulated in CRPC and high expression correlates with poor overall survival. Our study identifies the MLL complex as a co-activator of AR that can be targeted in advanced prostate cancer. ASH2L / Menin / MLL1 were knocked down using shRNA /siRNA in two prostate cancer cell lines, VCaP and LNCaP.
Project description:Resistance to androgen deprivation therapies and increased androgen receptor (AR) activity are major drivers of castration-resistant prostate cancer (CRPC). Prior work has focused on targeting AR directly; however, the identification and targeting of co-activators of AR signaling remains an underexplored area. Here we demonstrate that the MLL (mixed-lineage leukemia) complex, a well-known contributor in MLL-fusion-positive leukemia, acts as a co-activator of AR signaling. AR interacts with the MLL complex via its subunit, menin. Small molecule inhibition of the menin-MLL interaction blocks AR signaling and inhibits tumor growth in vivo. Furthermore, we find that menin is up-regulated in CRPC and high expression correlates with poor overall survival. Our study identifies the MLL complex as a co-activator of AR that can be targeted in advanced prostate cancer.
2015-03-02 | GSE60836 | GEO
Project description:The synthetic small molecule FL3 combats intestinal tumorigenesis via Axin1 inhibition of Wnt/Beta-catenin signaling
Project description:The unfolded protein response (UPR), a signaling pathway triggered by endoplasmic reticulum (ER) stress, is induced by a range of environmental factors. Here we describe the identification and characterization of a synthetic small molecule, erstressin, which activates the UPR. Erstressin induced rapid phosphorylation of PERK and eIF2a and the alternative splicing of XBP-1, hallmark initiating events of the UPR. Further, erstressin activated the transcription of multiple genes involved in the UPR. Coincident with these effects, erstressin also downregulated the transcription of the inflammation-associated enzyme inducible nitric oxide synthase (iNOS) in cytokine-activated cells. A close analog of erstressin that failed to induce the UPR did not attenuate expression of iNOS, suggesting that both biological effects of erstressin were mediated by a common mechanism. Further, the structurally-distinct ER stressor thapsigargin also inhibited iNOS expression. Together these chemical genetic studies reveal an unanticipated anti-inflammatory role for the UPR. Experiment Overall Design: We utilized microarrays to understand the global effect of a novel compund, erstressin, on cytokine stimulated cells over time.
Project description:Forced expression of pro-neural transcription factors was shown to mediate direct neuronal conversion of human fibroblasts. Since neurons are postmitotic, the conversion efficiency represents an important parameter. Here we present a minimalist approach combining two factor neuronal programming with small molecule-based inhibition of GSK3ß and SMAD signaling, which gives rise to functional neuron-like cells (iNs) of various neurotransmitter phenotypes with an overall yield of up to >200% and a final neuronal purity of up to >80%. Timcourse of reprogramming of fibroblasts towards an neuronal phenotype in two independent fibroblast lines
Project description:We previously identified SMIP004 (N-(4-butyl-2-methyl-phenyl) acetamide), as a novel inducer of cancer-cell selective apoptosis of human prostate cancer cells. SMIP004 decreased the levels of positive cell cycle regulators, such as cyclin A, CDK4 and SKP2 while upregulating cyclin-dependent kinase inhibitors p27 and p21, resulting in G1 arrest and inhibition of colony formation in soft agar. However, the mechanism of SMIP004-induced cancer cell selective apoptosis remained unknown. We used profiling to unravel a SMIP004-induced pro-apoptotic pathway, which initiates with bioenergetic reprogramming at the level of mitochondria. SMIP004 causes downregulation of aerobic glycolysis, rapid upregulation of components of the mitochondrial electron transport chain, and oxidative stress. The latter, in turn, elicits cell cycle arrest by rapidly targeting cyclin D1 for proteasomal degradation, drives transcriptional downregulation of the androgen receptor, and activates pro-apoptotic signaling through the unfolded protein response and MAPK activation. Finally SMIP004 was found to potently inhibit the growth of prostate and breast cancer xenografts in mice. There are two biological replicates SMIP004Rep1 and SMIP004Rep2 and two technical replicates for each biological replicates (SMIP004 Rep1_1 and SMIP004 Rep1_2). Total RNA from cells treated with 40 uM SMIP004 for 24 h, vehicle or positive controls (Roscovitine, 20uM, Campthotecin 500 nMM, Bortezomib 50 nM) was obtained using the RNeasy Mini Kit. The drug treated and control samples were compared.