BACKGROUND : 2-Ethyl-3-O-sulphamoyl-estra-1,3,5(10)16-tetraene (ESE-16) is a unique, in silico-designed compound
with possible anticancer properties, which were identified in our laboratory. This compound is capable of
interfering with microtubule dynamics and is believed to have potential carbonic anhydrase IX inhibiting activity.
In this study, it was investigated whether ESE-16 is capable of inducing apoptosis in vitro in the esophageal
carcinoma SNO cell line via the intrinsic pathway at a concentration of 0.2 μM with an exposure time of 24 hours.
RESULTS : Qualitative results were obtained via light microscopy, transmission electron microscopy and confocal
microscopy. Results showed hallmarks of apoptosis in the ESE-16-treated cells. In addition, data revealed an increase
in the number of ESE-16-treated cells blocked in metaphase. Cell death via apoptosis in the ESE-16-treated cells was
confirmed by studying the internal ultrastructure of the cells via transmission electron microscopy, while confocal
microscopy revealed abnormal spindle formation and condensed chromatin in ESE-16-treated cells, thus confirming
Quantitative results were obtained via flow cytometry and spectrophotometry. Cell death via apoptosis in ESE-16-treated
cells was quantitatively confirmed by the Annexin V-FITC apoptosis detection assay. Flow cytometry and
spectrophotometry revealed dissipation of mitochondrial membrane potential and an increase in superoxide
levels in the ESE-16-treated cells when compared to the relevant controls. Both initiator caspase 9 and effector
caspase 3 activities were increased, which demonstrates that ESE-16 causes cell death in a caspase-dependent manner.
CONCLUSIONS : This was the first in vitro study conducted to investigate the action mechanism of ESE-16 on an
esophageal carcinoma cell line. The results provided valuable information on the action mechanism of this
potential anticancer agent. It can be concluded that the novel in silico-designed compound exerts an anti-proliferative
effect on the esophageal carcinoma SNO cell line by disrupting microtubule function resulting in metaphase block.
This culminates in apoptotic cell death via the intrinsic apoptotic pathway. This research provided cellular targets
warranting in vivo assessment of ESE-16’s potential as an anticancer agent.