title: Chemically modified tetracyclines induce apoptosis in cultured mast cells.
abstract: Chemically modified tetracyclines are a group of non-antimicrobial tetracycline derivatives, which possess antiinflammatory, anticollagenolytic and antiproliferative properties. Here we studied the effects of four different chemically modified tetracyclines (CMT-1, CMT-3, CMT-8 and CMT-308) on proliferation and viability of cultured mouse and human mast cells. All studied CMTs (25 microM) effectively inhibited the viability and proliferation of human mast cell line (HMC-1) cells and mouse bone marrow derived mast cells (mBMMCs), as judged by trypan blue exclusion and by incorporation of [(3)H]thymidine. The antiproliferative effect of CMTs was not dependent on the stimulating growth factor, i.e. CMTs inhibited both IL-3 and c-kit ligand-induced proliferation of mBMMCs. The reduced viability of mast cells was due to induction of apoptosis, as indicated by the increased amount of apoptotic nucleosomes and the appearance of TUNEL positive cells in the presence of CMTs. The induction of apoptosis was further confirmed by showing that CMT-3 induces activation of caspase-3 and caspase-9 in HMC-1 cells. Additionally, CMT-3 induced downregulation of the expression of antiapoptotic Bcl-2 protein in HMC-1 cells. Compared to doxycycline, the antiproliferative and proapoptotic effects of different CMTs were clearly more pronounced. Of the studied CMTs, CMT-3 and CMT-8 appeared to be the most potent inhibitors of mast cell proliferation and survival. The present results show that CMTs have an antiproliferative and proapoptotic effect on both malignant and non-malignant mast cells. In conclusion, CMTs could offer a novel means to treat disorders with inappropriate expansion of mast cells, such as rheumatoid arthritis and systemic mast cell diseases.
authors.affiliation: Department of Medicine, Division of Rheumatology, Helsinki University Central Hospital, Kasarmikatu 11-13, 00130 Helsinki, Finland.
authors.forename: Charlotta
authors.initials: C
authors.lastname: Sandler
authors.forename: Katariina
authors.initials: K
authors.lastname: Nurmi
authors.forename: Ken A
authors.initials: KA
authors.lastname: Lindstedt
authors.forename: Timo
authors.initials: T
authors.lastname: Sorsa
authors.forename: Lorne M
authors.initials: LM
authors.lastname: Golub
authors.forename: Petri T
authors.initials: PT
authors.lastname: Kovanen
authors.forename: Kari K
authors.initials: KK
authors.lastname: Eklund
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D020169:Caspases / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D006801:Humans; D008407:Mast Cells / Q000187:drug effects*; D051379:Mice; D008807:Mice, Inbred BALB C; D013754:Tetracyclines / Q000494:pharmacology*
chemical_list: D013754:Tetracyclines; D020169:Caspases