title: Restoration of sensitivity to STI571 in STI571-resistant chronic myeloid leukemia cells.
abstract: STI571 induces sustained hematologic remission in patients with chronic myeloid leukemia (CML) in chronic phase. However, in advanced phases, especially blast crisis, the leukemia usually becomes resistant within months. It has been investigated whether resistance to STI571 is stable and immutable or whether it can be reversed in selected CML cell lines. Withdrawal of STI571 for varying lengths of time from cultures of 3 resistant lines (K562-r, KCL22-r, and Baf/BCR-ABL-r1) did not restore sensitivity to the inhibitor. In contrast, LAMA84-resistant cells experienced a sharp reduction in survival and proliferation during the first week of STI571 withdrawal but recovered thereafter. Moreover, when left off the inhibitor for 2 months or longer, this cell line reacquired sensitivity to STI571. It is hypothesized, therefore, that patients who have become resistant to the drug may respond again if STI571 therapy is temporarily interrupted.
authors.affiliation: Department of Haematology, Imperial College School of Medicine, Hammersmith Hospital, London, United Kingdom.
authors.forename: A J
authors.initials: AJ
authors.lastname: Tipping
authors.forename: F X
authors.initials: FX
authors.lastname: Mahon
authors.forename: V
authors.initials: V
authors.lastname: Lagarde
authors.forename: J M
authors.initials: JM
authors.lastname: Goldman
authors.forename: J V
authors.initials: JV
authors.lastname: Melo
mesh_terms: D000818:Animals; D001549:Benzamides; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D016044:Fusion Proteins, bcr-abl / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D000068877:Imatinib Mesylate; D017404:In Situ Hybridization, Fluorescence; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000188:drug therapy* / Q000473:pathology; D051379:Mice; D010766:Phosphorylation; D010879:Piperazines; D011743:Pyrimidines / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D014407:Tumor Cells, Cultured
chemical_list: D001549:Benzamides; D010879:Piperazines; D011743:Pyrimidines; D000068877:Imatinib Mesylate; D016044:Fusion Proteins, bcr-abl; C505409:Casp3 protein, mouse; D053148:Caspase 3; D020169:Caspases