Abstract:
2-Methoxyestradiol (2ME2) is a naturally occurring estradiol metabolite which possesses antiproliferative, antiangiogenic
and antitumor properties. However, due to its limited biological accessibility, synthetic analogues have been synthesized
and tested in attempt to develop drugs with improved oral bioavailability and efficacy. The aim of this study was to evaluate
the antiproliferative effects of three novel in silico-designed sulphamoylated 2ME2 analogues on the HeLa cervical
adenocarcinoma cell line and estrogen receptor-negative breast adenocarcinoma MDA-MB-231 cells. A dose-dependent
study (0.1–25 mM) was conducted with an exposure time of 24 hours. Results obtained from crystal violet staining indicated
that 0.5 mM of all 3 compounds reduced the number of cells to 50%. Lactate dehydrogenase assay was used to assess
cytotoxicity, while the mitotracker mitochondrial assay and caspase-6 and -8 activity assays were used to investigate the
possible occurrence of apoptosis. Tubulin polymerization assays were conducted to evaluate the influence of these
sulphamoylated 2ME2 analogues on tubulin dynamics. Double immunofluorescence microscopy using labeled antibodies
specific to tyrosinate and detyrosinated tubulin was conducted to assess the effect of the 2ME2 analogues on tubulin
dynamics. An insignificant increase in the level of lactate dehydrogenase release was observed in the compounds-treated
cells. These sulphamoylated compounds caused a reduction in mitochondrial membrane potential, cytochrome c release
and caspase 3 activation indicating apoptosis induction by means of the intrinsic pathway in HeLa and MDA-MB-231 cells.
Microtubule depolymerization was observed after exposure to these three sulphamoylated analogues.
