ABSTRACT
The effects of toremifene, a new antiestrogenic drug, were investigated in vitro on the exponentially growing human mammary carcinoma cell line MCF-7. The drug effects were monitored by serial cell counts and DNA flow cytometry. The inhibitory effect of toremifene on MCF-7 became greater as the drug concentration was increased from 1 microM to 10 microM. At 5 microM toremifene induced a large decrease in the relative percentages of S- and G2/M-phase cells, and an increase in the amount of cell debris, indicating increased cell death. After withdrawal of the drug the mammary cancer cells resumed logarithmic growth similar to that of control cells. The effects caused by toremifene were similar to those caused by tamoxifen both in quality and quantity.
Subject(s)
Antineoplastic Agents/pharmacology , Breast Neoplasms/pathology , Tamoxifen/analogs & derivatives , Cell Count , Cell Division/drug effects , Cell Survival/drug effects , Dose-Response Relationship, Drug , Flow Cytometry , Humans , Tamoxifen/pharmacology , Toremifene , Tumor Cells, Cultured/drug effectsABSTRACT
The effect of taxol, an experimental antitumor drug, was studied in vitro on human prostatic cancer cells. Different concentrations of taxol, varying from 5 microM to 0.01 nM, were used. The effect of taxol was examined by light and electron microscopy. Taxol had a marked cytotoxic effect on prostatic cancer cells down to a 10 nM concentration of taxol when observed by light microscopy. However, by electron microscopy, the specific effect of taxol was seen even with a 1 nM concentration of taxol. Taxol induced the appearance of numerous round cells after a few days and, subsequently, progressive death of the tumor cells. Among the surviving tumor cells, large tumor cells were noted as well as many multinucleated tumor cells. By electron microscopy, the round tumor cells showed mitotic figures with a high amount of cytoplasmic microtubules. Nonmitotic cells were often multinucleated and contained a high number of cytoplasmic microtubules and microtubule-related structures. The results show that taxol, even at very low concentrations, has a highly cytotoxic effect on prostatic cancer cells; and when a very low concentration of taxol is used with no obvious cytotoxic effect at the light microscopic level, specific taxol-induced ultrastructural alterations can be observed.
