DIFFERENTIAL EXPRESSION OF THE MT-1E GENE IN ESTROGEN-RECEPTOR-POSITIVE AND ESTROGEN-RECEPTOR-NEGATIVE HUMAN BREAST-CANCER CELL-LINES

The goal of this study was to determine which of the 10 functional met allothionein (MT) genes are expressed in four human breast cancer cell Lines and whether expression varies among the cell lines. Using rever se transcription polymerase chain reaction (RT-PCR) technology, it was shown that there was no expression of mRNA for the MT-1A, MT-1B, MT-1 F, MT-1G, MT-1H, MT-3, and MT-4 genes in any of the four cell Lines, A ll four cell lines were shown to express mRNA for the MT-2A and MT-1X genes, The expression level of mRNA for the MT-2A gene demonstrated mo dest differences among the cell lines, whereas expression of the MT-1X gene was consistent, In contrast, mRNA for the MT-1E gene was express ed in only two of the four cell lines and expression correlated to the estrogen receptor status of the cell lines, The two estrogen-receptor -positive cell lines showed no mRNA expression for the MT-1E gene, In the two estrogen-receptor-negative cell lines, mRNA expression for the MT-1E gene was elevated with expression levels similar to the houseke eping gene, glyceraldehyde-3-phosphate dehydrogenase. The cellular con tent of MT protein was also shown to be elevated in the estrogen-recep tor-negative cell lines that express MT-1E mRNA, These results suggest a possible relationship between estrogen receptor status and MT-1E ge ne expression in human breast cancer.