Small-scale screening program for the identification of cytotoxic Oxazolo[5,4-d]pyrimidine derivatives based on Whole Cell Viability Assay

Abstract

For over last couple of decades, there has been a robust activity aimed towards the discovery of novel anti-cancer therapeutics. An approach to identify starting points for new drug candidates is high throughput screening of compound library collection. In this work, we describe the application of a Tetrazolium-based, 96-well small scale screening assay to screen a mini library of 19 compounds bearing Oxazolo[5,4-d]pyrimidine structures against human umbilical vein endothelial cells. Primary actives identified against HUVEC were retested and the IC50 value compounds were estimated for HUVEC. The screening program (Primary screening) identified 4 compounds with inhibition rate percentage ≥ 70% each. Retest screening of these compounds, taking into account criteria required for high cytotoxic compounds, afforded a panel of 1 compound for further biological analysis. This compound had IC50 value of 12.19µM, 12.16µM, 10.24µM, 20.43µM for HUVECs, SGC7901, MCF7, and HeLa respectively. Furthermore, a clonogenic assay was performed in order to confirm the cytotoxic activity of the selected compound on the survival and proliferation of MCF7. This compound was found to significantly effect the survival and proliferation of MCF7. Taken together, the selected compound, namely SCYJ32, was found to be highly cytotoxic against the numerous cell lines. Further studies are ongoing in order to unravel various mechanisms of action of this novel small compound.