VOLUME 64 : 2016

There are various assays that can be performed to measure cell viability and apoptosis, which is why in this study, comparison of some common assays, MTT and resazurin reduction assays for cell viability and, Flow cytometry and caspase 3/7 for cell apoptosis, were performed in Doxorubicin (DOX) treated colorectal adenocarcinoma cells. These cell-based assays were analyzed in order to determine which of the paired methods are more efficient in measuring cell viability and apoptosis at various concentrations of DOX and varied incubation times. Results showed that incubation time has no effect on both cell viability assays (MTT and resazurin). Resazurin was observed to be more sensitive than MTT in measuring cell viability while MTT is more specific in determining cytotoxicity. In terms of cell apoptosis, caspase 3/7 is more specific and sensitive because of its enzyme substrate reaction. However, annexin V was more sensitive than caspase 3/7 in detecting early apoptosis, late apoptosis and discrimination of necrotic cell from apoptotic cell in DOX-treated colorectal adenocarcinoma cells. Depending on application, cellular based assays for both viability and apoptosis have to be routinely standardized as different factors may affect its result such as culture mediums, buffers, cell density, pH, incubation temperature, humidity, chemical constituents, drug dosage, and incubation time.

Keywords: MTT, resazurin, flow cytometry, caspase 3/7, luminescence assay