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

Lawaly Maman Manzo, Yijuan Cheng, Ling yang, Jiping liu, Ya Hui Deng, Li Ping Sun, Yu liu


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.


Cytotoxic ativity;small scale screening;MTT assay;clonogenic assay

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