Novel 7-substituted camptothecins with potent antitumor activity

J Med Chem. 2000 Oct 19;43(21):3963-9. doi: 10.1021/jm000944z.

Abstract

The natural alkaloid camptothecin is the lead compound of a new class of antitumor agents with a unique mechanism of action (i.e. inhibition of DNA topoisomerase I). The pharmacological interest of these agents has generated a large number of derivatives and analogues endowed with potent cytotoxic activity, two of them being in clinical use as antitumor drugs. We have synthesized a new series of camptothecins substituted in position 7 with an alkyl or alkenyl chain bearing cyano and/or carbethoxy groups. These compounds showed potent cytotoxic activity in vitro against the human non-small-cell lung carcinoma H460 cell line, most of them exhibiting IC(50) values in the 0.05-1 microM range, more active than topotecan used as a reference compound. In particular 7-cyano-20S-camptothecin (5a) showed high in vitro cytotoxicity against a topotecan-resistant H460 cell subline (H460/TPT) and a cisplatin-resistant ovarian carcinoma subline (IGROV-1/Pt 1). In an in vivo evaluation of the antitumor activity, 5a appeared significantly more effective than topotecan in the H460 tumor model and comparable with topotecan in a small-cell lung carcinoma model and a colon carcinoma model. The efficacy and good tolerability of this compound increase interest for further preclinical development.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antineoplastic Agents / chemical synthesis*
  • Antineoplastic Agents / chemistry
  • Antineoplastic Agents / pharmacology
  • Camptothecin / analogs & derivatives*
  • Camptothecin / chemical synthesis*
  • Camptothecin / chemistry
  • Camptothecin / pharmacology
  • Drug Screening Assays, Antitumor
  • Humans
  • Mice
  • Mice, Nude
  • Structure-Activity Relationship
  • Tumor Cells, Cultured

Substances

  • 7-cyanocamptothecin
  • Antineoplastic Agents
  • Camptothecin