Modification of growth in small heat shock (hsp27) gene transfected breast carcinoma.

The role of hsp27 in the regulation of cell growth has been investigated in the breast cancer cell line MDA-MB-23 1. Cells were co-transfected with an expression vector carrying the human hsp27 gene (pSG-2711) and a plasmid conferring neomycin resistance (pWlneo). Transfected cells were selected for neomycin resistance. Stable transfectants were used as a pooled population for further experiments, since single-cell colonies were not able to grow into mass culture under continuous selection pressure. Over-expression of hsp27 was analysed by immunohistochemistry and immunoblotting. Cells only transfected for neomycin were used as control cells. The growth rate of the transfected cell line was determined whether overexpression of hsp27 directly influences the growth properties of the cells. Growth analysis of transfected cell lines in vitro revealed a lower proliferation rate of the hsp27 overexpressing cells compared to controls. These data suggest that hsp27 is involved in downregulation of cell proliferation in this human breast cancer cell line.