I. DIGREM input instructions
1. Drug-treated gene expression data
Gene expression profiles of single compound-treated and
negative control-treated cell line sample. Data needs to be log transformed.
2. Dose-response curve data (optional)
Dose-response curves for viability of the cell lines you used for gene expression assay.
For each compound, two data points(viability reduction in IC20 and double dose
of IC20) from the dose-response curve are desired.
3. Pathway information
Pathway information is used to estimate the drug similarity of effect on upstream and downstream
genes.
The KEGG pathway is a universal gene network database, but it is not context-specific. Users can
choose
to upload their own gene-gene interaction information if their data is generated on specific
cancer cell lines that have a unique gene regulatory relationship.
By taking the above three inputs, DIGREM will calculate the pair synergistic scores of all
possible combinations of the compound provided, and their rank from the most synergistic to
the most antagonist. A larger score indicates a higher possibility for the pair to have synergistic
effect, and vice versa.
II. DIGREM methods instruction
The DIGREM will automatically call three methods to do the prediction if the requirements are met, and will output the predicted result of each method.
1. DIGRE model
DIGRE is the method with the fewest requirements, and therefore it is always run. It takes the
above-mentioned three inputs to do the prediction with tolerance of no dose response data. See
Details
2. IUPUI_CCBB model
The IUPUI_CCBB method requires the gene expression data to have at least three replicates for each
drug
(to ensure enough statistical power). If the requirement is met, this method will be run, and the
prediction will be added to the final output report. Otherwise this method is skipped. See
Details
3. Gene set-based model
The gene set-based method requires the gene expression data to contain at least 16 columns to do
normalization. If the requirement is met, this method will be run, and the
prediction will be added to the final output report. Otherwise this method is skipped. See Details
4. Correlation-based model
The correlation-based method also requires relatively large gene expression data matrix (at least 16
drugs or replicates). If the requirement is met, this method will be run. Based on our experience,
this method has the least consistency with the other three methods, we suggest fousing more on
prediction of the other three methods. See
Details
III. DIGREM outputs instruction
1. Heatmap
A heatmap of DIGRE-predicted synergistic scores. Dark blue represents high predicted synergy value,
and white represents low synergy value. Only the upper triangle of the results is displayed.
2. Bar plot
Bar plot of compound pairs with top DIGRE synergistic scores.
3. Download file
Raw predicted score of all compound pairs by DIGRE, IUPUI_CCBB and gene set-based method.