Clofazimine and B4121 sensitize an intrinsically resistant human colon cancer cell line to P-glycoprotein substrates

Oncol Rep. Jan-Feb 2000;7(1):193-5.


The potential of B4121 to sensitize three intrinsically resistant human colon cancer cell lines (CaCo2, ATCC HTB 37; COLO 32 DM, ATCC CCL 220; HT-29, ATCC HTB 38) to vinblastine, doxorubicin, daunorubicin, paclitaxel, taxotere and cisplatin at a non-toxic, therapeutically relevant concentration of 0.25 microg/ml was compared with that of clofazimine at a similar concentration. The cell line expressing high levels of P-glycoprotein (P-gp), COLO 320 DM, was susceptible to chemosensitization by the experimental agents for the P-gp substrates (paclitaxel, taxotere, daunorubicin, vinblastine and doxorubicin) but not for cisplatin. CaCo2 cells expressed lower levels of P-gp and were only marginally susceptible to sensitization by any one of these drugs, except in the case of sensitization by B4121 for doxorubicin and taxotere, whereas the HT-29, a P-gp negative cell line, was unaffected. The riminophenazines, especially B4121, might prove useful as combination treatment in circumventing P-gp mediated resistance of colon cancers.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATP Binding Cassette Transporter, Subfamily B, Member 1 / analysis*
  • Clofazimine / analogs & derivatives*
  • Clofazimine / pharmacology*
  • Colonic Neoplasms / drug therapy*
  • Drug Resistance, Multiple*
  • Drug Resistance, Neoplasm
  • Flow Cytometry
  • Humans
  • Tumor Cells, Cultured


  • ATP Binding Cassette Transporter, Subfamily B, Member 1
  • B 4121
  • Clofazimine