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Laser capture microdissection and proteomics. : Possibilities and limitation 분 자 유 전 학 실 험 실 석 사 1 차 최 용 욱. Tissue heterogeneity & enrichment strategies. Tissue heterogeneity : complexity of many tissue samples 1) The biologically relevant cell type is often in the
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Laser capture microdissectionand proteomics : Possibilities and limitation 분 자 유 전 학 실 험 실 석 사 1차 최 용 욱
Tissue heterogeneity & enrichment strategies • Tissue heterogeneity : complexity of many tissue samples 1) The biologically relevant cell type is often in the minority 2) Such samples aren't ideally suited to direct analysis • Enrichment strategies for selected cell types 1) Growth of cell line from tissue sample 2) Amplifying a specific cell population 3) primary and established cell lines
Fresh and primary cultures by using 2-D PAGE : alteration in the level & number of protein but significant similarity Fresh TCC Primary cultured TCC
Laser capture microdissection(LCM) • The limitation of tissue in size and quantity from patient
Laser Capture Microdissection(LCM) Steps prepare place capture microdissect extract incubate analyze
2-D PAGE & LCM • 2-D PAGE is the central separation tool in proteomic analysis and its compatibility with LCM <2-D gels of LCM procured cercal epithelium & total cervical tissue>
SELDI • Surface-enhanced laser desorption/ionization(SELDI)
Differential Protein Expression ProfilingProtein Purification
Assay development & protein-protein interaction Peptide Mapping
SELDI analysis of colon carcinogenesis
SELDI & LCM • SELDI is sensitive down to the femtomole(10-15)/ attomole(10-18) level ☞ much smaller amounts of material than 2-D PAGE • Profiles have been generated from as few as 25 to 50 cells ☞ Making SELDI ideally suited to the analysis of LCM procured material • Most appropriate for low molecular weight proteins (<20kDa)
Antibody technologies and LCM • selection of Ab specific for disease : LCM procured materialforepitope source ☞ Getting the disease specific Ab by comparing normal tissue • Immunoassays : increasingly used to analyze specific proteins in extracts from LCM captured material for biomarker • LCM based approach making use of protein lysate arrays provides a high throughput alternative for marker validation.
Concluding remarks • LCM - an important part to play in proteomics research from initial marker discovery to marker validation • Necessary to consider the need for the enrichment LCM – Even though it is too early to assess • Comparative analyses by reducing the level of false positives resulting from differential heterogeneity of cell type between normal and diseased samples • Profiling of protein modification using LCM procured material