Metallothionein isoform 3 expression inhibits cell growth and increases drug resistance of PC‐3 prostate cancer cells

Abstract

BACKGROUND The third isoform of metallothionein (MT-3) is overexpressed in prostate cancers and PIN lesions. The expression of MT-3 is highly variable but appears to correlate to Gleason score. The goal of the present study was to determine the effect of MT-3 overexpression on the growth of the PC-3 prostate cancer cell line. METHODS PC-3 cells were stably transfected with either the MT-3 or MT-1E gene. Cell growth was determined by counting DAPI-stained nuclei, drug resistance by the colony formation assay, MT mRNA expression by reverse transcriptase-polymerase chain reaction, and MT protein by immunoblot. RESULTS PC-3 cells that overexpress the MT-3 gene are growth inhibited compared with either untransfected cells, cells with blank vector, or cells with similar overexpression of the MT-1E gene. Furthermore, increased chemotherapeutic drug resistance occurred in PC-3 clones derived from MT-3– and MT-1E–transfected cells. CONCLUSION The overexpression of MT-3 can influence the growth and chemotherapeutic drug resistance of the PC-3 prostate cancer cell line. Prostate 52: 89–97, 2002.