Semester

Summer

Date of Graduation

2003

Document Type

Dissertation

Degree Type

PhD

College

Davis College of Agriculture, Natural Resources and Design

Department

Biochemistry

Committee Chair

Joginder Nath.

Abstract

Metallothioneins (MT) are a family of low molecular weight (6 kDa) cysteine rich proteins that participate in a variety of functions such as detoxification of heavy metals and homeostasis of essential metals. They can also act as scavengers of free radicals. MT-1 and 2 isoforms are ubiquitously expressed, whereas the expression of the third isoform is limited to the neural tissue. 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 2 estrogen receptor positive (MCF-7 and T-47D) and 2 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 immunoblot. It was demonstrated that MCF-7 and Hs578T cells that overexpress the MT-3 gene are 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 4 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.

Download

Share

COinS