Structure-activity relations, cytotoxicity and topoisomerase II dependent cleavage induced by pendulum ring analogues of etoposide

Eur J Cancer. 1990;26(5):590-3. doi: 10.1016/0277-5379(90)90084-7.


The cytotoxicity of etoposide and its analogues, dihydroxy (DHVP), o-quinone (VP-Q) and o-methyl (VP-OMe), was evaluated in human breast (MCF-7) and HL60 tumour cells. Although less potent than etoposide, both DHVP and VP-Q were cytotoxic to these cells. However, VP-OMe was inactive. Studies with purified topoisomerase II showed that the intensity of DNA cleavage and the pattern of cleavage were similar for DHVP, VP-Q and etoposide. In contrast, the VP-OMe failed to induce DNA cleavage, indicating that the presence of 4'-OH is essential for metabolism, induction of topoisomerase II-mediated DNA cleavage and cytotoxicity of etoposide and its analogues.

MeSH terms

  • Breast Neoplasms / metabolism
  • Cell Survival / drug effects
  • DNA Damage
  • DNA Topoisomerases, Type II / metabolism*
  • DNA, Neoplasm / drug effects*
  • DNA, Neoplasm / metabolism
  • Etoposide / analogs & derivatives
  • Etoposide / pharmacology*
  • Female
  • Humans
  • Structure-Activity Relationship
  • Tumor Cells, Cultured / drug effects*


  • DNA, Neoplasm
  • Etoposide
  • DNA Topoisomerases, Type II