Project description:Analysis of the effects of a dual specificity PI3K/mTOR inhibitor on two human ovarian cell lines, OV2008 and MCAS. Results provide insight into the adaptive response to PI3K/mTOR inhibition in matrix attached ovarian cancer cells. The PI3K/mTOR-pathway is the most commonly deregulated pathway in epithelial cancers and thus represents an important target for cancer therapeutics. Here we show that dual inhibition of PI3K/mTOR in ovarian cancer 3D-spheroids leads to death of the inner matrix-deprived cells, whereas matrix-attached cells are resistant. Resistance is associated with up-regulation of a cellular survival program that involves both FOXO-regulated transcription and a novel translational resistance mechanism resulting in specific up-regulation of IRES-mediated, cap-independent translation. Inhibition of any of several up-regulated proteins, including Bcl-2, EGFR, or IGF1R, abrogates resistance to dual PI3K/mTOR inhibition. These results demonstrate that acute adaptive response to PI3K/mTOR inhibition resembles well-conserved adaptive response to nutrient and growth factor deprivation and how development of rational drug combinations can bypass resistance mechanisms. Total RNA was isolated 6h and 24h after treatment with 1 M-NM-<M NVP-BEZ235 or DMSO vehicle control from 3D grown structures
Project description:Glioblastoma (GBM) is the most lethal primary brain cancer that lacks effective molecular targeted therapies. PI3K/AKT/mTOR signaling pathway is activated in 90% of all Glioblastoma Multiforme (GBM) tumors. To gain insight into the impact of the PI3K Pathway on GBM metabolism, we treated U87MG GBM cells with 50nM NVP-BEZ235 (PI3K and mTOR a dual inhibitor) for four days and identified differentially expressed genes with RNA-seq analysis.
Project description:Analysis of the effects of a dual specificity PI3K/mTOR inhibitor on two human ovarian cell lines, OV2008 and MCAS. Results provide insight into the adaptive response to PI3K/mTOR inhibition in matrix attached ovarian cancer cells. The PI3K/mTOR-pathway is the most commonly deregulated pathway in epithelial cancers and thus represents an important target for cancer therapeutics. Here we show that dual inhibition of PI3K/mTOR in ovarian cancer 3D-spheroids leads to death of the inner matrix-deprived cells, whereas matrix-attached cells are resistant. Resistance is associated with up-regulation of a cellular survival program that involves both FOXO-regulated transcription and a novel translational resistance mechanism resulting in specific up-regulation of IRES-mediated, cap-independent translation. Inhibition of any of several up-regulated proteins, including Bcl-2, EGFR, or IGF1R, abrogates resistance to dual PI3K/mTOR inhibition. These results demonstrate that acute adaptive response to PI3K/mTOR inhibition resembles well-conserved adaptive response to nutrient and growth factor deprivation and how development of rational drug combinations can bypass resistance mechanisms.
Project description:Capicua–double homeobox 4 (CIC-DUX4) rearranged sarcomas (CDSs) are extremely rare, highly aggressive primary sarcomas that represent a major therapeutic challenge. To identify selective therapeutic targets of CDS, we performed RNA sequencing of primary tumor samples from patients, patient-derived xenografts (PDXs) and PDX-derived cell lines and we highlighted an HMGA2/IGF2BPs/IGF2/IGF1R/AKT-mTOR axis that characterizes CDS. This highly active axis confers to CDSs sensitivity to both trabectedin, which prevents HMGA proteins from binding to IGF2BP2/3 promoters, and PI3K/mTOR inhibitor NVP-BEZ235 (dactolisib). Combined treatments with trabectedin and NVP-BEZ235 completely abolish the activation of the IGF2/IGF1R/AKT/mTOR axis and the in vivo growth of CDS tumors. The development of representative PDXs and PDX-derived cell lines models has helped to identify the unique sensitivities of CDS towards AKT/mTOR inhibitors and trabectedin, revealing a mechanism-based therapeutic strategy to fight this lethal cancer.
Project description:The mTOR-allosteric inhibitor, RAD001, in combination with a PI3K/mTOR ATP-site competitive inhibitor, BEZ235, causes gene reprogramming, autophagy and tumor regression, in a mouse model approximating human HCC with poor prognosis, leading to an investigator Phase 1B-2 clinical trial. Comparative study of total RNA obtained from normal and tumor liver tissue under RAD001, BEZ235, or RAD001 + BEZ235.
Project description:Mutations in Hedgehog (Hh) pathway genes, leading to constitutive activation of Smoothened (Smo), occur in sporadic medulloblastoma, the most common brain cancer in children. Antagonists of Smo induce tumor regression in mouse models of medulloblastoma and hold great promise for targeted therapy for this tumor. However, acquired resistance has emerged as one of the major challenges of targeted cancer therapy. Here, we describe novel mechanisms of acquired resistance to Smo antagonists in medulloblastoma. NVP-LDE225, a potent and selective Smo antagonist, inhibits Hh signaling and induces tumor regressions in allograft models of medulloblastoma that are driven by mutations of Patched (Ptch), a tumor suppressor in the Hh pathway. However, after long-term treatment, evidence of acquired resistance was observed. Genome-wide profiling of resistant tumors revealed distinct mechanisms to evade the inhibitory effects of Smo antagonists. Chromosomal amplification of Gli2, a downstream effector of Hh signaling, reactivated Hh signaling and restored tumor growth. Analysis of pathway gene-expression signatures selectively deregulated in resistant tumors identified increased phosphoinosite-3-kinase (PI3K) signaling as another potential resistance mechanism. Probing the functional relevance of increased PI3K signaling, we showed that the combination of NVP-LDE225 with the dual PI3K/mTOR inhibitor NVP-BEZ235 markedly delayed the development of resistance. Our findings have important clinical implications for future treatment strategies in medulloblastoma. mRNA profiling: RNA was prepared from tumours from vehicle or NVP-LDE225 treated nude mice allografted with medulloblastoma tumors derived from Ptch+/-p53-/- transgenic mouse and hybridized on Affymetrix Mouse Genome 430 2.0 RNA expression array. The dosage terminology (BID & QD) reflects the dosing schedule, where BID = twice a day, QD = once a day. aCGH: DNA was prepared from tumors from vehicle or NVP-LDE225 treated nude mice allografted with medulloblastoma tumors derived from Ptch+/-p53-/- transgenic mouse and hybridized on Agilent mouse CGH 244K Array.
Project description:Phosphatidylinositol-3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway activation contributes to mantle cell lymphoma (MCL) pathogenesis and drug resistance. However, the use of mTOR inhibitors as single agents have shown limited clinical efficacy in relation with drug activation of feedback loops. Selective PI3K inhibition or dual PI3K/mTOR catalytic inhibition are different therapeutic approaches developed to achieve effective pathway blockage. Here, we evaluated the antitumor activity of a mTOR inhibitor, a pan-PI3K inhibitor and a dual PI3K/mTOR inhibitor in primary MCL cells. We found that dual PI3K/mTOR inhibitor modulated angiogenesis, tumor invasiveness and cytokine signaling compared to a mTOR inhibitor and a pan-PI3K inhibitor in MCL. We used microarrays to compare the effect of these three compounds in MCL and identified distinct classes of down-regulated genes modulated by each compound. Global RNA expression in primary cells from two MCL patients treated with a mTOR inhibitor, a pan-PI3K inhibitor and a dual PI3K/mTOR inhibitor for 8 hours
Project description:Mutations in Hedgehog (Hh) pathway genes, leading to constitutive activation of Smoothened (Smo), occur in sporadic medulloblastoma, the most common brain cancer in children. Antagonists of Smo induce tumor regression in mouse models of medulloblastoma and hold great promise for targeted therapy for this tumor. However, acquired resistance has emerged as one of the major challenges of targeted cancer therapy. Here, we describe novel mechanisms of acquired resistance to Smo antagonists in medulloblastoma. NVP-LDE225, a potent and selective Smo antagonist, inhibits Hh signaling and induces tumor regressions in allograft models of medulloblastoma that are driven by mutations of Patched (Ptch), a tumor suppressor in the Hh pathway. However, after long-term treatment, evidence of acquired resistance was observed. Genome-wide profiling of resistant tumors revealed distinct mechanisms to evade the inhibitory effects of Smo antagonists. Chromosomal amplification of Gli2, a downstream effector of Hh signaling, reactivated Hh signaling and restored tumor growth. Analysis of pathway gene-expression signatures selectively deregulated in resistant tumors identified increased phosphoinosite-3-kinase (PI3K) signaling as another potential resistance mechanism. Probing the functional relevance of increased PI3K signaling, we showed that the combination of NVP-LDE225 with the dual PI3K/mTOR inhibitor NVP-BEZ235 markedly delayed the development of resistance. Our findings have important clinical implications for future treatment strategies in medulloblastoma.
Project description:To examine whether MTDH is a novel RNA binding protein and regulates either metabolism or translation of various mRNAs, we performed a RNA-binding protein immunoprecipitation (RIP) with MTDH and IgG antibodies, and the resulting immunoprecipitated RNA was subjected to a microarray to identify transcripts associating with MTDH. In addition we tested the effect of PI3K inhibition using BEZ235 (a dual PI3K/mTOR inhibitor) on the association of MTDH with target mRNAs. The microarray was performed on three biological triplicates as well as three experimental triplicates of immunoprecipitated MTDH and IgG in Hec50co endometrial cancer cells. Magna RIP (RNA-binding protein immunoprecipitation, Millipore) Kit and microarray were used to immunoprecipitate MTDH associated RNAs and to identify mRNAs that associate with MTDH in the absence or presence of 100nM BEZ235 (LC Labs). Fold changes represent immunoprecipitated MTDH RNA compared to IgG immunoprecipitated RNA. Representative mRNAs associated with MTDH and the effect of BEZ235 on the association of MTDH with mRNAs are shown.
Project description:To examine whether MTDH is a novel RNA binding protein and regulates either metabolism or translation of various mRNAs, we performed a RNA-binding protein immunoprecipitation (RIP) with MTDH and IgG antibodies, and the resulting immunoprecipitated RNA was subjected to a microarray to identify transcripts associating with MTDH. In addition we tested the effect of PI3K inhibition using BEZ235 (a dual PI3K/mTOR inhibitor) on the association of MTDH with target mRNAs.