Search for chemotherapeutic cancer treatment is one of the most acute problems of modern pharmacology. To pursue this issue Life Chemicals has prepared the Anticancer Library using similarity search within its proprietary stock collection of HTS compounds against publicly available databases of compounds possessing antitumor activity.

42,000 Compounds screened by National Cancer Institute as part of the DTP Human Tumor Cell Line Screen project were downloaded and merged with the corresponding screening data expressed as GI50.

The NCI renamed the IC50 value, the concentration that causes 50% growth inhibition, into the GI50value to emphasize the correction for the cell count at time zero; thus, GI50 is the concentration of test drugwhere 100 × (T - T0)/(C - T0) = 50. The optical density of the test well after a 48-h period of exposure to test drug is T, the optical density at time zero is T0, and the control optical density is C. The GI50 measures the growth inhibitory power of the test agent.

NCI library was filtered down to 3,151 most potent compounds showing GI50 values below 50 nM.

This set of compounds was tested in 60 human cancer cell lines.

Life Chemicals database was searched for compounds similar to each of the selected 3,151 NCI compounds using the 80% similarity cut-off (Tanimoto) on MDL public keys fingerprints. This effort yielded 28,000 hits that were included into Life Chemicals Anticancer Library.

Results could be traced back to the specific cell lines.