DNA Microarray /Expression
안성환
(주)지노믹트리
Genomictree GeneTrack Human DNA microarray
DNA Microarray
Intron
Exon: 4만gene - PCR product
- Oligo DNA
. Methylation assay
AAAA
RNA Protein
CGCGAT GCGCTA
CG C GAT C G GCGCTAAC
CH
3SNP 증폭
결실 C
DNA Chromosome
LOH
자극 전달
반응 MSI
expression
Methylation
Genetic and Epigenetic alteration through second hit affects on gene expression
miRNA
환경
유전자1
유전자2 유전자3
Central Dogma ? Central Dogma ?
DNA
mRNA Protein
근육세포 피부세포 신경세포
유전자1
유전자2 유전자3
Normal Cell Cancer Cell
어떻게 차이를 구분할 것인가?
정상세포와 암세포 : 유전자 활동차이
RNA identification and differential detection
in molecular level
Northern blot Primer extension RNase Protection RT-PCR
DD-PCR
Real time –PCR Microarray
Profile of Differential Expression Single gene
To
Genomic level
P32*
Probe (gene)Target(total RNA)
C T C T
C T
Test Control
2
6
Probe (gene)
Cy3 Cy5
Target(total RNA)
C T
Test Control 6
2
3X
6 2
3X
Northern Blot Array-based Blot
2 6
N
N N
N
N
N
Individual Amplification RT-PCR
Individual detection
Gel-based assay Microarray-based Assay
Hybridization RNA
From low to High throughput Assay
Multiplex amplification RT or PCR
Gel
electrophoresis
Human 35K
Row 27 x Column 27 x 48 blocks = 34,992genes Printing Area : 54 mm x 18 mm
Hybridization image
2.5 cm7.5 cm
Printing area: 5.4 X 1.8 cm
Genomictree
Each gene in each well of plate
Robotic machine
Pin head
Open slot
Pin : capillary
DNA microarray
-Total RNA
Target labeled
Reference(N) Test(T)
Cy5-dUTP Cy3-dUTP
Scan
microarray experiment
=
Hybridization Level
⇒ Cy5 Cy3
Normal
Tissue cancer
Tissue
Competitive hybridization
Equal mix
Reverse transcription
DATA MINING
control Test
Probe
Up regulated gene No change Down regulated gene Competitive hybridization
Ratio of intensity
Noncompetitive hybridization
Control RNA Test RNA
1. Scanning 30분전에 scanner를 power-on하여 pre-warming.
2. GT-microarray hybridization method에 의해 실험이 수행된 microarray를
GenePix 4000(Axon) scanner로 가지고 온다.
4. Scanner의 덮개를 좌측으로 미끄러지듯이 열고, microarray를 넣는다.
5. Cassette 좌측의 lever를 움직여, microarray를 고정시킨다.
6. Scanner 덮개를 닫으면, scan할 준비가 된다.
9. “Prescan ” icon을 click한다.
- 전체 microarray의 대략적인 실험 결과, scan하기 위한 spot 위치등의 파악.
10. Spot의 위치가 파악되면, “stop ” icon을 click하여, prescan을 멈춘다.
② Prescan으로 spot의 위치가 파악된다.
③ “Stop” icon을 click
Prescan
진행 방향① “Prescan” 시작
18. Gridding file을 선택하면 각 spot(feature)에 맞게 제작된 grid box가 나 온다. Mouse와 keyboard를 사용하여, 모든 grid box를 각 spot(feature)에 알 맞게 위치시킨다. (자동으로 alignment하므로, 정확하게 맞출 필요는 없다.)
크게 확대하여 작업하면 더욱 정확하게 위치 시킬 수 있다.
20. Alignment가 완료된 후, “Analyze ” icon을 click.
→ 모든 data가 excel의 형식으로 나타난다.
① “Analyze” icon을 click.
② Data가 analysis 되는 진행상황이 보인다.
Alignment가 된 feature
Data로 쓸 수 없어 flag-out된 feature
21. Data analysis가 끝난 후, excel과 scatterplot 형식으로 output되는 data.
Result panel Scatter-plot panel
2X up-regulated genes
2X down-regulated genes
22. “Results” panel에서, Sum of Median 값이 <1000인 feature를 제거(flag- out)하여, false-positive를 최대한 감소시킨다.
① “sum of median”을 click하면, 자동으로 sorting이 된다.
② mouse와 shift+mouse 를 사용하여 flag-out 할 범위를 지정한다.
③ 범위가 지정된 후, mouse 오른쪽 click 하여, “Flag-bad”를 선택하면, 지정된 범위는 삭제된다.
Flag-out된 feature는 Scatter-plot에서 사라진다.
Profiling Patterns of Gene expression to HCV core protein in Hepatocytes
Unsuitable spots flagged and excluded
Gridding
Clustering Gene
net signal
Average pixel intensity of each spot minus local background intensity equals net signal of each spot
Up-regulated genes Down-regulated genes
Test : core expression ( Tet-minus ) Cy5
Reference : no core expression (Tet plus) Cy3
vs 3h
6h
48hrs
465 gene
> 2 fold on at least one array
> 80% good spot
> 50 Ch1 and Ch2 net norm
Clustering
465 genes selectedDown- Up-
Insufficient
Tree
View
200 10000 50.00 5.64 4800 4800 1.00 0.00 9000 300 0.03 -4.91
Cy3 Cy5
Cy5 Cy3
Cy5
log2 Cy3
Genes
Experiments
DNA microarray 분석 system
Up
Down
Clustering
Data Submit
Data Extract
Graphical
display
GT DB
Experiments n-1
Tree View
Down-regulated
Up-regulated normal cancer
oncogene
Tumor surppressor
Target discovery and development via expression profiling
Low grade lesions
high grade lesions
Normal
tissue ASCUS LSIL HSIL CIS SCC Cancer
SIL : Squamous intraepithelial lesion CIS : Carcinoma in situ
SCC : Squamous cell carcinoma
Low SIL High SILDevelopment of Cervical Cancer
Phenotype---Æ host molecular classification
HPV genotype
Expression Kinetics during disease progression
Low grade : Group A
High grade : Group B
Differentially expressed genesNormal LSIL HSIL CIS Cancer
Selection for genes gradually down-regulated in cancer formation
Expression profile of cervical biopsy sample
(ANOVA, p < 0.01)
Gene expression signature as Predictor Of Survival in Breast Cancer
-Inkjet-synthesized oligonucleotide microarrays, 25000 oligos -70-gene prognosis profile,98 patients
-295 consecutive breast cancer patients
-Gene-expression profile is a more powerful predictor of -Disease outcome in young breast cancer patients than
Standard systems
Van de Vijver MJ, et al. NEJM2002.
Van’t Veer LJ, et al. Nature 2002
MammaPrint R Test Technology
provides the means for selecting patients who would benefit from adjuvant therapy and those who can be spared the serious impact of these treatments
-Regulating cell cycle -Invasion
-Metastasis -angiogenesis
Primary breast tumor Supervised classification 70gene selected
Strongly predict poor prognosis Agendia,Inc
Personalized approach and classification to Cancer through Genomics and Epigenomics
Phenotype
Genotype
Early detection and right classification New generation of in-vitro
Diagnosis and prognosis
-> better treatment
Diagnostics move towards earlier detection
and differential diagnostics for unmet medical needs utilizing Nucleic Acid-based Molecular markers
tumor mass (cell)
10
810
4Genetic Predisposition
tests
dysplasia Early cancer Cancer screening test
Tumor diagnostics
Timeline of carcinogenesis
Cancer in-situ Clinically overt cancer Relapse/metastasis
Early detection( non or less invasive))
Theranostics(differential)
Monitoring Therapy recurrences
DNA-based
DNA or RNA- based
Tumor
Control vs Tumor
SNPs
CGH, cDNA
Oligonucleotide
Antibody chip Analysis
Tumor classification Identification of clusters or
Individual marker genes
Clinical validation with
tissue microarrays
General scheme of the procedure used in tumor expression profiling for target identification and validation
Microarray hybridization
Methylation
Genetic
Epigenetic
We need clinical research collaboration
Novel markers
Clinical assessment of
predictive value discovery
Standard of care
Pilot studies &
Assay development
Phase I
Retrospective clinical analysis
Phase II
Prospective confirmatory analysis
Phase III Phase IV
Multi-institutional Validation trials
SNPs
CGH, cDNA
Oligonucleotide
Antibody
Methylation
Eearly detection prognosis