title: Substances from the medicinal mushroom Daedalea gibbosa inhibit kinase activity of native and T315I mutated Bcr-Abl.
abstract: Human chronic myelogenous leukemia (CML) is a malignancy of pluripotent hematopoietic cells characterized by a distinctive cytogenetic abnormality resulting in the creation of a p210 Bcr-Abl fusion protein with abnormal tyrosine kinase activity. Recently, a selective Abl kinase inhibitor, Imatinib mesylate, was introduced as a first line therapy for CML. Despite the initial response, CML patients develop a resistantance to Imatinib, which is mediated mainly by point mutations within the Abl protein. Herein, we describe the identification of mycelium organic extracts of Daedalea gibbosa with selective anti-proliferating and apoptosis-inducing activities against K562 cells and other laboratory model of CML. Using activity-guided purification, we isolated an active fraction, F6, which inhibits in vitro kinase activity of recombinant Abl. The active fraction significantly inhibits the autophosphorylation of native and mutated Bcr-Abl, which are resistant to Imatinib treatment including the T315I mutation. Using a colony-forming assay, we demonstrated that the active fraction is effective in inhibiting the colony formation of the Ba/F3 cell line harboring either native Bcr-Abl or its mutations, including the T315I mutation. Our data illustrated the potential of natural products in cancer therapeutics.
authors.affiliation: Cancer Drug Discovery Program, Migal, Galilee Technology Center, Kiryat Shmona 11016, Israel.
authors.forename: Majed
authors.initials: M
authors.lastname: Yassin
authors.forename: Solomon P
authors.initials: SP
authors.lastname: Wasser
authors.forename: Jamal
authors.initials: J
authors.lastname: Mahajna
mesh_terms: D000363:Agaricales / Q000737:chemistry*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001549:Benzamides; D015153:Blotting, Western; D002454:Cell Differentiation / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects*; D002478:Cells, Cultured; D003114:Colony-Forming Units Assay; D004797:Enzyme-Linked Immunosorbent Assay; D005656:Fungal Proteins / Q000302:isolation & purification / Q000494:pharmacology*; D016044:Fusion Proteins, bcr-abl; D006801:Humans; D000068877:Imatinib Mesylate; D020014:K562 Cells / Q000378:metabolism / Q000473:pathology; D051379:Mice; D009154:Mutation / Q000235:genetics*; D010766:Phosphorylation / Q000187:drug effects; D010879:Piperazines / Q000494:pharmacology; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors* / Q000235:genetics; D016315:Proto-Oncogene Proteins c-abl / Q000037:antagonists & inhibitors; D011743:Pyrimidines / Q000494:pharmacology
chemical_list: D001549:Benzamides; D005656:Fungal Proteins; D010879:Piperazines; D011743:Pyrimidines; D000068877:Imatinib Mesylate; D011505:Protein-Tyrosine Kinases; D016044:Fusion Proteins, bcr-abl; D016315:Proto-Oncogene Proteins c-abl