In vitro effects of pentosan polysulfate against malignant breast cells

Pentosan polysulfate (Elmiron); (Alza Pharmaceuticals, Mountain View, CA) is the only Food and Drug Administration–approved oral therapy for interstitial cystitis (IC). Women with IC and breast cancer are often in the same age range; therefore, we hypothesize that pentosan polysulfate may also have a therapeutic effect on breast cancer cells in vitro. Breast cancer lines MCF-7, ZR75-1, and HTB26 were treated with pentosan polysulfate at various concentrations. Cell viability was measured at 24 hours by MTT. Annexin V assay was used to determine the effect of pentosan polysulfate on apoptotic and necrotic activity. Pentosan polysulfate significantly inhibited the growth of the ZR75-1 cells; however, significant cellular proliferation was observed in the MCF-7 cells. A significant change in late apoptotic activity was observed with pentosan polysulfate treatment in vitro. Caution should be used in prescribing pentosan polysulfate for the treatment of IC in patients who are both in high-risk groups for breast cancer and premenopausal females.