Sulphamoylated 2-methoxyestradiol analogues induce apoptosis in adenocarcinoma cell lines

PLoS One. 2013 Sep 5;8(9):e71935. doi: 10.1371/journal.pone.0071935. eCollection 2013.

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 μM) was conducted with an exposure time of 24 hours. Results obtained from crystal violet staining indicated that 0.5 μM 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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 2-Methoxyestradiol
  • Adenocarcinoma
  • Antineoplastic Agents / pharmacology*
  • Apoptosis / drug effects*
  • Caspase 3 / metabolism
  • Cell Shape / drug effects
  • Cytochromes c / metabolism
  • Drug Screening Assays, Antitumor
  • Enzyme Activation
  • Estradiol / analogs & derivatives*
  • Estradiol / pharmacology
  • HeLa Cells
  • Humans
  • Membrane Potential, Mitochondrial / drug effects
  • Microscopy, Electron, Transmission
  • Microtubules / metabolism
  • Protein Multimerization / drug effects
  • Sulfonamides / pharmacology
  • Tubulin / chemistry
  • Tubulin / metabolism
  • Tubulin Modulators / pharmacology

Substances

  • Antineoplastic Agents
  • Sulfonamides
  • Tubulin
  • Tubulin Modulators
  • Estradiol
  • 2-Methoxyestradiol
  • Cytochromes c
  • CASP3 protein, human
  • Caspase 3

Grants and funding

Research was supported by grants from the Cancer Association of South Africa (AK246), the Medical Research Council (AG374, AK076), National Research Foundation, RESCOM (UP) and Struwig Germeshuysen Trust (AJ038). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.