Design, synthesis, and biological evaluation of doxorubicin-formaldehyde conjugates targeted to breast cancer cells

J Med Chem. 2004 Feb 26;47(5):1193-206. doi: 10.1021/jm030352r.


The anthracycline antitumor drug doxorubicin (DOX) has been utilized for decades as a broad-spectrum chemotherapeutic. Recent literature evidence documents the role of formaldehyde in the cytotoxic mechanism, and anthracycline-formaldehyde conjugates possess substantially enhanced activity in vitro and in vivo. Targeting a doxorubicin-formaldehyde conjugate specifically to cancer cells may provide a more efficacious chemotherapeutic. The design and 11-step synthesis of doxorubicin-formaldehyde conjugates targeted to the estrogen receptor, which is commonly overexpressed in breast cancer cells, are reported. The formaldehyde is incorporated in a masked form as an N-Mannich linkage between doxorubicin and salicylamide. The salicylamide triggering molecule, previously developed to release the doxorubicin-formaldehyde active metabolite, is tethered via derivatized ethylene glycols to an E and Z mixture of 4-hydroxytamoxifen. The targeting group, E/Z-4-hydroxytamoxifen, was selected for its ability to tightly bind the estrogen receptor and antiestrogen binding sites. The targeted doxorubicin-formaldehyde conjugates' estrogen receptor binding and in vitro growth inhibition were evaluated as a function of tether length. The lead compound, DOX-TEG-TAM, bearing a triethylene glycol tether, binds the estrogen receptor with a binding affinity of 2.5% relative to E/Z-4-hydroxytamoxifen and inhibits the growth of four breast cancer cell lines with 4-fold up to 140-fold enhanced activity relative to doxorubicin.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Antineoplastic Agents / chemical synthesis*
  • Antineoplastic Agents / chemistry
  • Antineoplastic Agents / pharmacology
  • Binding, Competitive
  • Breast Neoplasms
  • Cell Division / drug effects
  • Cell Line
  • Cell Line, Tumor
  • Doxorubicin / chemistry*
  • Drug Design
  • Drug Screening Assays, Antitumor
  • Drug Stability
  • Estrogen Receptor Modulators / chemical synthesis*
  • Estrogen Receptor Modulators / chemistry
  • Estrogen Receptor Modulators / pharmacology
  • Female
  • Formaldehyde / chemistry*
  • Humans
  • Hydrolysis
  • Models, Molecular
  • Polyethylene Glycols / chemistry
  • Receptors, Estrogen / drug effects
  • Receptors, Estrogen / metabolism
  • Stereoisomerism
  • Structure-Activity Relationship
  • Tamoxifen / analogs & derivatives*
  • Tamoxifen / chemistry


  • Antineoplastic Agents
  • Estrogen Receptor Modulators
  • Receptors, Estrogen
  • Tamoxifen
  • afimoxifene
  • Formaldehyde
  • triethylene glycol
  • Polyethylene Glycols
  • Doxorubicin