Structural Consideration in Designing Organotin Polyethers to Arrest the Growth of Breast Cancer Cells In Vitro

The ability to inhibit cancer is inherent in organotin materials yet the structural relationships that regulate/direct this activity remains unknown. We measured antitumor activity using a matched pair of cell lines MDA-MB-231 cells that are estrogen-independent, estrogen receptor negative and MCF-7 cells, a cell line that is estrogen receptor (ER) positive. Those polyethers that contained a O-phenyl unit were able to significantly inhibit the non-estrogen sensitive cell line but were much less effective against the estrogen sensitive cell line; that is, the human breast cancer cell line MDA-MB-231 showed better test results for polymers derived from diols containing the O-phenyl moiety than the breast cancer cell line MCF-7, a well-characterized estrogen receptor positive control cell line. Those polyethers that did not contain the O-phenyl unit inhibited both cell lines approximately the same. The differential activity of the O-phenyl-containing polyethers is likely due to the estrogen-sensitive cells combining with some of the organotin polyethers minimizing their ability to inhibit cell growth.