Structure-activity relationship and molecular mechanisms of ethyl 2-amino-6-(3,5-dimethoxyphenyl)-4-(2-ethoxy-2-oxoethyl)-4H-chromene-3-carboxylate (CXL017) and its analogues

J Med Chem. 2011 Aug 25;54(16):5937-48. doi: 10.1021/jm200764t. Epub 2011 Aug 3.


Multidrug resistance (MDR) in cancer is a phenomenon in which administration of a single chemotherapeutic agent causes cross-resistance of cancer cells to a variety of therapies even with different mechanisms of action. Development of MDR against standard therapies is a major challenge in the treatment of cancer. Previously we have demonstrated a unique ability of CXL017 (5) to selectively target MDR cancer cells and synergize with mitoxantrone (MX) in HL60/MX2 MDR cells. Here we expand its scope and demonstrate that 5 can synergize with both vincristine and paclitaxel in three different MDR cell lines (HL60/DNR, K562/HHT300, and CCRF-CEM/VLB100). We also demonstrate that 5 has potent cytotoxicity in the NCI-60 panel of cell lines with an average IC(50) of 1.04 μM. In addition, 5 has a unique mechanism of action in comparison with standard agents in the NCI database based on COMPARE analysis. Further structure-activity relationship study led to the development of a more potent analogue, compound 7d, with an IC(50) of 640 nM in HL60/MX2. Additionally, one enantiomer of 5 is 13-fold more active than the less active enantiomer. Taken together, our study has led to the discovery of a series of analogues that selectively target drug-resistant cancer cells with the potential for the treatment of drug-resistant cancers.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antineoplastic Agents / chemistry
  • Antineoplastic Agents / pharmacology
  • Benzopyrans / chemistry*
  • Benzopyrans / pharmacology*
  • Cell Line, Tumor
  • Cell Survival / drug effects
  • Daunorubicin / pharmacology
  • Drug Resistance, Multiple / drug effects*
  • Drug Resistance, Neoplasm / drug effects*
  • Drug Synergism
  • HCT116 Cells
  • HL-60 Cells
  • HT29 Cells
  • Humans
  • Inhibitory Concentration 50
  • K562 Cells
  • Mitoxantrone / pharmacology
  • Molecular Structure
  • Neoplasms / drug therapy
  • Neoplasms / pathology
  • Paclitaxel / pharmacology
  • Stereoisomerism
  • Structure-Activity Relationship
  • Vincristine / pharmacology


  • Antineoplastic Agents
  • Benzopyrans
  • ethyl 2-amino-6-(3,5-dimethoxyphenyl)-4-(2-ethoxy-2-oxoethyl)-4H-chromene-3-carboxylate
  • Vincristine
  • Mitoxantrone
  • Paclitaxel
  • Daunorubicin