title: Modulation of natural killer susceptibility by indole alkaloid tumor promoter dihydroteleocidin B.
abstract: The indole alkaloid tumor promoter dihydroteleocidin B (DHTB) was shown to reduce the natural killer (NK) cell susceptibility of two established cell lines, U937 and K562. The decrease in NK susceptibility correlated with the induction of differentiation as documented by positive benzidine staining in the erythroleukemia K562 and by antibody-dependent cellular cytotoxicity effector function in the histiocytic lymphoma line U937, respectively. In contrast, DHTB treatment did not alter the NK sensitivity of the NK-resistant B-lymphoblastoid-cell line RPMI 8866. Cold target inhibition experiments suggested that both effector-target recognition and post-recognition steps were affected by DHTB. These results lend further support to the notion that NK susceptibility of a given tumor cell may vary with the stage of differentiation.
mesh_terms: D000470:Alkaloids / Q000494:pharmacology*; D001667:Binding, Competitive; D002273:Carcinogens / Q000494:pharmacology*; D002460:Cell Line; D002471:Cell Transformation, Neoplastic / Q000187:drug effects; D003602:Cytotoxicity, Immunologic / Q000187:drug effects*; D006801:Humans; D007694:Killer Cells, Natural / Q000187:drug effects* / Q000276:immunology; D007700:Kinetics; D004915:Leukemia, Erythroblastic, Acute / Q000276:immunology; D016403:Lymphoma, Large B-Cell, Diffuse / Q000276:immunology; D008235:Lyngbya Toxins
chemical_list: D000470:Alkaloids; D002273:Carcinogens; D008235:Lyngbya Toxins; C022229:dihydroteleocidin B