Peripheral-type benzodiazepine receptor levels correlate with the ability of human breast cancer MDA-MB-231 cell line to grow in scid mice

MDA-MB-231 (MDA-231) human breast cancer cells have a high proliferation rate, lack the estrogen receptor, express the intermediate filament vimentin, the hyaluronan receptor CD44, and are able to form tumors in nude mice. The MDA-231 cell line has been used in our laboratory to examine the role of the peripheral-type benzodiazepine receptor (PBR) in the progression of cancer. During these studies 2 populations of MDA-231 cells were subcloned based on the levels of PBR. The subclones proliferated at approximately the same rate, lacked the estrogen receptor, expressed vimentin and CD44, and had the same in vitro chemoinvasive and chemotactic potential. Both restriction fragment length polymorphism and comparative genomic hybridization analyses of genomic DNA from these cells indicated that both subclones are of the same genetic lineage. Only the subclone with high PBR levels, however, was able to form tumors when injected in SCID mice. These data suggest that the ability of MDA-231 cells to form tumors in vivo may depend on the amount of PBR present in the cells.