title: Stable transfection and overexpression of metallothionein isoform 3 inhibits the growth of MCF-7 and Hs578T cells but not that of T-47D or MDA-MB-231 cells.
abstract: The third isoform of metallothionein (MT-3) is overexpressed in some breast cancers and its expression is associated with a poor disease outcome. In the PC-3 prostate cancer cell line, MT-3 expression has been shown to inhibit cell growth and increase drug resistance. The goal of the present study was to determine if MT-3 overexpression would influence the growth of human breast cancer cell lines. To determine this, the coding sequence of the MT-3 gene was stably transfected into two estrogen receptor positive (MCF-7 and T-47D) and two estrogen receptor negative cell lines (Hs578T and MDA-MB-231) having no basal expression of MT-3. Cell growth was determined by counting DAPI-stained nuclei, cadmium resistance by the colony formation assay, MT mRNA expression by RT-PCR, and MT protein by immuno-blot. It was demonstrated that MCF-7 and Hs578T cells that overexpress the MT-3 gene were growth inhibited compared to untransfected cells. In contrast, T-47D and MDA-MB-231 cells that overexpress MT-3 were not growth inhibited. Stable transfection of the MT-1E gene had no effect on the growth of any of the four cell lines. It was also demonstrated that the overexpression of both MT-3 and MT-1E only increased the resistance of MCF-7 cells to Cd(+2). In all instances, stable transfection of the MT-3 or MT-1E gene had no effect on the expression of the other MT isoforms. The study shows that MT-3 can influence the growth of some breast cancer cell lines.
authors.affiliation: Department of Pathology, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58202-9037, USA.
authors.forename: Volkan
authors.initials: V
authors.lastname: Gurel
authors.forename: Donald A
authors.initials: DA
authors.lastname: Sens
authors.forename: Seema
authors.initials: S
authors.lastname: Somji
authors.forename: Scott H
authors.initials: SH
authors.lastname: Garrett
authors.forename: Joginder
authors.initials: J
authors.lastname: Nath
authors.forename: Mary Ann
authors.initials: MA
authors.lastname: Sens
mesh_terms: D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007536:Isomerism; D008668:Metallothionein / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: D012333:RNA, Messenger; D011960:Receptors, Estrogen; D008668:Metallothionein