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MEDC601. Bioinformatics. Lecture by Brad Windle Ph# 628-1956 email: bwindle@vcu.edu Office: Massey Cancer Center, Goodwin Labs Room 319. Web site for lecture:. http://www.people.vcu.edu/~bwindle/Courses/MEDC601. Profile. A set of data or characteristics pertaining to an item.
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MEDC601 Bioinformatics Lecture by Brad Windle Ph# 628-1956 email: bwindle@vcu.edu Office: Massey Cancer Center, Goodwin Labs Room 319 Web site for lecture: http://www.people.vcu.edu/~bwindle/Courses/MEDC601
Profile A set of data or characteristics pertaining to an item Profiles are sometimes referred to as Signatures or Fingerprints
Gene/Protein Sequence Protein Structure Drug Structure Disease Cellular Profiles Gene Expression Protein SNPs Expression Protein States Structural Genomic Cell State DNA Methylation Drug Response Misc Metabolitics Data
Gene/Protein Sequence Protein Structure Drug Structure Cellular Profiles Gene Expression Protein SNPs Expression Protein States Structural Genomic DNA Methylation Drug Response Misc Metabolitics Data
Profiles Have Two Sides A gene profile across samples and a sample profile across genes
Bioinformatics uses tools for learning from the Profiles There are two basic forms of learning Unsupervised Learning Supervised Learning
Supervised Learning Definition: Learning from example Unsupervised Learning Definition: Learning from observation Exploration Let the data reveal what you learn You can learn that what you did not expect Allows you to formulate relevant hypotheses It’s a hypothesis generator It’s focused Allows you to test relevant hypotheses but it doesn’t usually allow you to prove the hypothesis It often involves statistical or computational modeling Usually requires experimental validation of what you learn
Supervised Learning Examples of methods QSAR Modeling, Prediction model Classification Model, eg., Is a patient a good candidate for a particular drug treatment? Simulation Modeling, eg., Cell simulation
Why can’t we observe the patterns unaided? The patterns are too complex or abstract. There’s too much data. There’s too much noise.
R R R R R R Drug-related profiles Drug profile based on structure Structure profile based on drugs drug1 drug1 drug 2 drug 3 drug 4 e1 e2 e3 e4 e5 e6 e1 How phys/chem properties relate to biological or biochemical properties, such cell killing or enzyme activity is within the realm of QSAR
Cell profile based on various drug sensitivities Drug profile based on cell sensivities cell1 cell2 cell3 cell4 cell5 cell6 cell1 drug1 drug2 drug3 drug4 drug5 drug6 drug 1
COMPARE NCI 60 cell lines profiled for sensitivity to drugs How do drugs relate to each other based on cellular response? How do cells relate to each other based on drug response?
A major tool in unsupervised learning is Cluster Analysis It evaluates how similar items are to each other Do they have similar patterns within their profiles? How relatively close the items are to each other There are various ways to measure closeness
Cell response profile Monks et al. Anti-Cancer Drug Design 12:553 (1997)
Cell line clusters based on drug response Cell clusters correspond cell type to a limited extent Scherf et al, nature genetics 24:236 (2000)
Drug clusters correspond to drug targets or mechanisms of action not necessarily drug structure. Scherf et al, nature genetics 24:236 (2000)
COMPARE is a resource for exploring targets and mechanisms Your compound of interest can be profiled and compared to the profiles for >70,000 compounds Compounds with good matches may have known characteristics, such as target and mechanism, thus revealing a possible target and mechanism for your compound http://dtp.nci.nih.gov/docs/compare/compare.html
Wallqvist Study Wallqvist et al, Molecular Cancer Therapeutics 1:311-320 (2002) Found genes that correlated with drug sensitivity Hypothesized that some of those gene’s proteins are the target of the drugs that correlated with gene expression
Drugs Start with drug response, identify drugs based on correlation with genes 1 2 3 Genes Identified genes based on correl with drugs 1 2 3 Proteins Identify corresponding protein for each gene from structural protein database (PDB) 1 2 3 Ligands Identify small compounds (ligands) that have been fitted to proteins using 3D modeling 1 2 3 Identify ligands with structural correlation with drugs
Compounds screened in NCI 60 cell lines Compounds with structural similarity to ligands Corresponding proteins in 3D structural database Genes that correlate with compounds in NCI 60 cell lines Compounds that bind in silico to proteins
calcium/calmodulin-dependent protein kinase I protein kinase C The similarity between the ligand specific for the protein and the drug that correlates with expression of the protein (gene) suggests that the drug is targeting the protein (interacting) Wallqvist et al, Molecular Cancer Therapeutics 1:311-320 (2002)
alcohol dehydrogenase 5 Wallqvist et al, Molecular Cancer Therapeutics 1:311-320 (2002)
4 sets of data DR GEP PDB Ligand Gene-Drug correlation Gene to Protein translation Protein-Ligand prediction Ligand-Drug correlation