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Published byLester Welch Modified over 9 years ago
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Not division…But growth
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Cells must grow
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PI3K GFR Akt Rheb Ras mTOR Tuberin/ Hamartin PTEN Neurofibromin Tuberous sclerosis complex Neurofibromatosis type 1 (NF1) Cowden Syndrome Lhermitte-Duclos disease S6KeIF4E NPM ARF p68
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Thinking about translation
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The forgotten translation…top m RNA s Terminal Oligo Pyrimidine tracts: 5’-CTTTCTTCTC…
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Raptor mLST8 mTOR Rictor mLST8 mTOR FKBP12 Actin cytoskeleton Ribosomal biogenesis Protein translation Rapamycin
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PDK1 PTEN Mutations 5% LOH ~30% Akt Akt2 amplified < 5% S6K1 Amplified ~10% (17 q 23) PIK3CA Mutations in ~25% overall Gene amplification < 10% (~25%) (~45%) (<7%) ER + HER2 + ER + /HER2 + ER - /HER2 - ? m TOR NPM ? 4E-BP1 ? e If4e ? The growth pathway is subject to enormous mutation rates
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PIK3CA mutations in ~25% of breast cancers (~25%) (~45%) (<7%) ER + HER2 + ER + /HER2 + ER - /HER2 - ~275 samples from ER + patients undergoing Letrozole therapy Developed sequencing pipeline for Exons 1,6,7,9,20 with GSC Goal 1: Attack the genotype Figure adapted from Cancer Res 65: 2554 Hypothesis: pik3ca mutations render tumors resistant to ER- and HER2-targeted therapies
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CONSERVATION OF NUCLEOLAR STRUCTURE/FUNCTION RESIDENTSDRIFTERS NPM/B23 NCL/C23 Fibrillarin Cdc14B Nop5/Sik Bop1 R-proteins hnRNP’s TCOF1 NUMA1 Ki67 p19ARF Cdc14A TERT WRN ING1 PP1 SMN1 UBF Mdm2 MdmX Cyclin E p53 DKC1 PES1 BLM Mammals(~450) drosophilaYeast(~39)zebrafishxenopus
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D. Trere (2000) Micron 31:127-131 UNIFORM AgNOR & SAPA SCORING METHOD
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RIBOSOMAL GENES AND THE NUCLEOLUS FIVE rGENE CLUSTERS CHR. 13, 14, 15, 21, 22 OVER 400 TANDEM REPEATS ~47 KB REPEAT ELEMENT YIELDS 13KB TRANSCRIPT
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Processing is everything
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r rna modifications
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Suppressing transcription…first important clue
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Lots of steps to mess with…
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Myc sends us another clue…
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S6K eIF4E Protein Synthesis NPM 40 60 40 60 40 60 Ribosomal Export rRNA Transcription CYTOPLASM NUCLEOLUS TIF1A RNA Pol I 40 60 mTOR
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Nuclear export nucleus cytosoplasm AAAAAAAA-3’ 5’ 60S 40S m TOR S6K NPM nucleolus Nucleophosmin acts in a late r RNA stage
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Nucleophosmin is mutated in human cancers
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nucleus cytosoplasm nucleolus 60S 40S 60S 40S AAAAAAAA-3’ 5’ PI3K S6K NPM r RNA Export Polysomes Protein synthesis This mutant is hyperactive in r RNA export
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…The pathway can be addictive mTORC2 Rac1 NPM rRNA Export Rapamycin Neurofibromin K-Ras Polysomes Proteins None LY Rap Nf1+/+Nf1-/- Tubulin S6 P Neurofibromin controls the growth pathway
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PI3K CELL SURVIVALCELL GROWTHCELL PROLIFERATION Nucleolar Integrity ARF/ p 53 Rapamycin ARF m TOR S6K NPM r RNA Export Polysomes Protein synthesis The pathway must have checks in place
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THE INK4A-ARF LOCUS Fibrosarcomas Lymphomas Gliomas Melanomas Fibrosarcomas Lymphomas Gliomas 11 11 23 Ink4a / ARF Cyclin D-Cdk4Mdm2 Rb p 53 ?
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Pol III 5S Pol I 5.8S18S 28S NUCLEOLUSNUCLEOPLASM 5S--- rp L5---NPM ARF 60S NUCLEAR EXPORT Synchronized ribosome export
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Layers of potential targets… RTK Ras p85 p110 PDK1 AKT PTEN P P P P MDM2 IKK eNOS TSC1/2 GSK3 FOXO Myc mTOR Cyclin D p53 NF- B p27kip1 Rheb cdk4 eIF4E NPM 28S 18S 5.8S 5S ARF S6K 4E-BP1 28S18S5.8S
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