title: Antisense down-regulation of metallothionein in a human monocytic cell line alters adherence, invasion, and the respiratory burst.
abstract: A human monocyte-derived cell line (THP-1) was used as a model to investigate the role of metallothionein (MT) in the cellular physiology of resting and activated monocytes. MT protein levels were reduced in THP-1 cells by transient transfections with an antisense MT expression vector. Antisense mouse MT-1 RNA was constitutively expressed under the control of the H-2Kb (mouse major histocompatibility complex I) promoter and could be further induced by lipopolysaccharide (LPS) treatment. THP-1 cells expressing antisense MT RNA (aMT-THP-1) had a 30% reduction in MT protein levels. In the absence of LPS treatment, aMT-THP-1 cells demonstrated increased production of H2O2 concurrent with enhanced adherence and invasiveness compared to cells transfected with the control vector (cv-THP-1). Treatment of aMT-THP-1 cells with LPS depressed these activation-associated responses and further reduced the level of MT protein. cv-THP-1 cells activated by LPS produced high levels of H2O2 and adhered to and invaded a reconstituted basement membrane. In addition to increasing cadmium sensitivity, diminished MT levels affected broad-ranging processes associated with resting and activated monocyte function. Thus, metallothionein plays an important physiological role in cells in addition to its role in detoxification of heavy metals.
authors.affiliation: Department of Pathology, University of Western Ontario, London, Canada.
authors.forename: M E
authors.initials: ME
authors.lastname: Leibbrandt
authors.forename: R
authors.initials: R
authors.lastname: Khokha
authors.forename: J
authors.initials: J
authors.lastname: Koropatnick
mesh_terms: D001483:Base Sequence; D002448:Cell Adhesion / Q000235:genetics / Q000502:physiology*; D002462:Cell Membrane / Q000378:metabolism; D015536:Down-Regulation / Q000502:physiology*; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D007223:Infant; D008297:Male; D008668:Metallothionein / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D008969:Molecular Sequence Data; D009000:Monocytes; D016372:RNA, Antisense / Q000378:metabolism*; D016897:Respiratory Burst / Q000235:genetics / Q000502:physiology*; D013997:Time Factors; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: D016372:RNA, Antisense; D008668:Metallothionein; D006861:Hydrogen Peroxide