View
214
Download
1
Category
Tags:
Preview:
Citation preview
Not division… But growth
Cells must growCells must grow
PI3K
GFR
Akt
Rheb
Ras
mTOR
Tuberin/Hamartin
PTEN
Neurofibromin
Tuberous sclerosis complex
Neurofibromatosis type 1 (NF1)
Cowden Syndrome Lhermitte-Duclos
disease
S6KeIF4E
NPMARF p68
Thinking about translationThinking about translation
The forgotten translation…top The forgotten translation…top mmRNARNAss
Terminal Oligo Pyrimidine tracts: 5’-CTTTCTTCTC…
RaptormLST8
mTOR
RictormLST8
mTOR
FKBP12
Actin cytoskeleton
Ribosomal biogenesis
Protein translation
Rapamycin
PDK1
PTENMutations 5%LOH ~30%
Akt Akt2 amplified < 5%
S6K1 Amplified ~10% (17q23)
PIK3CA Mutations in ~25% overallGene amplification < 10%
(~25%)(~25%)(~45%)(<7%)
ER+
HER2+
ER+/HER2+
ER-/HER2-
?
mTOR
NPM ?
4E-BP1?
eIf4e?
The growth pathway is subject to enormous mutation ratesThe growth pathway is subject to enormous mutation rates
PIK3CA mutations in ~25% of breast cancers
(~25%)(~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 genotypeGoal 1: Attack the genotype
Figure adapted from Cancer Res 65: 2554
Hypothesis: pik3ca mutations render tumors resistant to ER- and HER2-targeted therapies
CONSERVATION OF NUCLEOLAR STRUCTURE/FUNCTION CONSERVATION OF NUCLEOLAR STRUCTURE/FUNCTION
RESIDENTS DRIFTERS
NPM/B23NCL/C23
FibrillarinCdc14B
Nop5/SikBop1
R-proteinshnRNP’s
TCOF1NUMA1
Ki67p19ARF
Cdc14ATERTWRNING1PP1
SMN1UBF
Mdm2MdmX
Cyclin Ep53
DKC1PES1BLM
MammalsMammals(~450)(~450)
drosophiladrosophila
YeastYeast(~39)(~39)zebrafishzebrafish
xenopusxenopus
D. Trere (2000) D. Trere (2000) MicronMicron 3131:127-131:127-131
UNIFORM AgNOR & SAPA SCORING METHODUNIFORM AgNOR & SAPA SCORING METHOD
RIBOSOMAL GENES AND THE NUCLEOLUSRIBOSOMAL GENES AND THE NUCLEOLUS
FIVE rGENE CLUSTERSFIVE rGENE CLUSTERSCHR. 13, 14, 15, 21, 22CHR. 13, 14, 15, 21, 22OVER 400 TANDEM REPEATSOVER 400 TANDEM REPEATS~47 KB REPEAT ELEMENT~47 KB REPEAT ELEMENTYIELDS 13KB TRANSCRIPTYIELDS 13KB TRANSCRIPT
Processing is everythingProcessing is everything
rrrna modificationsrna modifications
Suppressing transcription…first important clueSuppressing transcription…first important clue
Lots of steps to mess with…Lots of steps to mess with…
Myc sends us another clue…Myc sends us another clue…
S6K
eIF4E
ProteinSynthesis
NPM
40
60 40
6040
60
RibosomalExport
rRNATranscription
CYTOPLASM
NUCLEOLUS
TIF1A
RNA Pol I
40
60
mTOR
Nuclear export
nucleus
cytosoplasm
AA
AA
AA
AA
-3’
5’60S 40S
mTOR
S6K
NPM
nucleolus
Nucleophosmin acts in a late Nucleophosmin acts in a late rrRNA stageRNA stage
Nucleophosmin is mutated in human cancersNucleophosmin is mutated in human cancers
nucleus
cytosoplasm
nucleolus
60S40S
60S40S
AA
AA
AA
AA
-3’
5’
PI3K
S6K
NPM
rRNA Export
Polysomes
Proteinsynthesis
This mutant is hyperactive in This mutant is hyperactive in rrRNA exportRNA export
…The pathway can be addictive
mTORC2
Rac1
NPM
rRNA Export
Rapamycin
Neurofibromin K-Ras
Polysomes
Proteins
None NoneLY LYRap Rap
Nf1+/+ Nf1-/-
Tubulin
S6P
Neurofibromin controls the growth pathwayNeurofibromin controls the growth pathway
PI3K
CELL SURVIVAL CELL GROWTH CELL PROLIFERATION
Nucleolar Integrity
ARF/p53
Rapamycin
ARF
mTOR
S6K
NPM
rRNA Export
Polysomes
Protein synthesis
The pathway must have checks in placeThe pathway must have checks in place
THE THE INK4A-ARFINK4A-ARF LOCUS LOCUS
FibrosarcomasLymphomas
Gliomas
Melanomas FibrosarcomasLymphomas
Gliomas
1 1 2 3
Ink4a/ARF
Cyclin D-Cdk4 Mdm2
Rb p53
?
Pol III
5S
Pol I
5.8S18S28S
NUCLEOLUS NUCLEOPLASM
5S---rpL5---NPM
ARF
60S
NUCLEAREXPORT
Synchronized ribosome exportSynchronized ribosome export
Layers of potential targets…Layers of potential targets…
RTK
Ras
p85p110
PDK1 AKT
PTENP P
PP
MDM2
IKK
eNOS
TSC1/2
GSK3
FOXO
Myc mTOR
Cyclin D
p53
NF-B
p27kip1
Rhebcdk4
eIF4ENPM
28S
18S
5.8S5S
ARF S6K 4E-BP1
28S 18S 5.8S
Recommended