estramustine and Colonic-Neoplasms

LS 4477 and LS 4559, two of a series of N-acyl-aminoalkyl phenyl ethers, are rationally designed compounds based on the tubulin binder estramustine. This study investigated their mechanism of action and compared their effectiveness in relation to estramustine in vitro against a panel of human and murine cell lines and in vivo against two murine colon tumour models (MAC). At biologically relevant concentrations, LS 4477 and LS 4559 caused a 59.9 and 56% reduction in tubulin assembly, respectively, compared with a 28.4% reduction in tubulin assembly by estramustine. The analogues were approximately 100 times more potent in chemosensitivity tests in vitro than the parent compound. Both analogues were orally active against the MAC 15A murine tumour model, to a greater extent than estramustine, producing significant growth delays (P<0.01). Significant activity was also shown against the slower growing MAC 26 tumour for LS 4577 (the soluble pro-drug of LS 4559). The results presented in this study suggest these compounds warrant further development with a view to assessing their clinical activity.

Topics: Animals; Antineoplastic Agents, Alkylating; Binding, Competitive; Colchicine; Colonic Neoplasms; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Estramustine; Inhibitory Concentration 50; Male; Mice; Microtubules; Prodrugs; Swine; Tubulin; Tubulin Modulators; Tumor Cells, Cultured

Estramustine (EM), an antimicrotubule agent, binds microtubule-associated proteins, causes spindle disassembly, and arrests cells at the late G2/M phase of the cell cycle. Since cells in the G2/M phase are the most radiosensitive and some human cancer cells contain high level of EM-binding protein, experiments were carried out to determine whether radiation sensitization could be obtained in human carcinoma cells.. Cells containing a high level of EM-binding protein such as prostate carcinoma (DU-145), breast carcinoma (MCF-7), and malignant glioma (U-251) were used to demonstrate radiosensitization. Cervical carcinoma (HeLa-S3) and colon carcinoma (HT-29) cells which are not known to contain EM-binding protein were also employed. Cell survival was assayed by the colony forming ability of single plated cells in culture to obtain dose-survival curves.. Pretreatment of DU-145, MCF-7, and U-251 cells to a nontoxic concentration (5 microM) of EM for more than one cell cycle time, substantially enhanced the radiation-induced cytotoxicity. The sensitizer enhancement ratio of these cells ranged from 1.35-1.52. The magnitude of the enhancement was dependent on the drug concentration and exposure time. The rate of cell accumulation in G2/M phase, as determined by flow cytometry, increased with longer treatment time in the cell lines which showed radiosensitization. Other antimicrotubule agents such as taxol and vinblastine caused minimal or no radiosensitization at nontoxic concentrations.. The data provide a radiobiological basis for using EM as a novel radiation enhancer, with the property of tissue selectivity.

Topics: Breast Neoplasms; Cell Cycle; Cell Survival; Colonic Neoplasms; Combined Modality Therapy; Estramustine; Female; Flow Cytometry; Glioma; HeLa Cells; Humans; Male; Microtubules; Neoplasms; Paclitaxel; Prostatic Neoplasms; Radiation-Sensitizing Agents; Tumor Cells, Cultured; Vinblastine

The present study describes a new microscopic perifusion technique for detecting momentary alterations in cell volume and shape. The method has been applied for evaluating early signs of cytotoxicity following chemotherapeutic treatments. The effects of estramustine phosphate (EMP) have been evaluated. EMP is a complex between oestradiol-17 beta and the alkylating agent nor-nitrogen mustard and has recently demonstrated a marked cytotoxicity against malignant glioma cells. The results showed a concentration-dependent increase in cell size and a concomitant decrease in shape factor following EMP-treatment of glioma cells. These changes correlated with cytotoxicity evaluated as cell proliferation and cell membrane alterations shown by 86Rb fluxes and ultrastructural visible membrane damage. The colon cancer line HT-29 displayed no reactions at all following EMP treatment. It is suggested that acute alterations in cell morphology and shape display a strong correlation to the cytotoxicity of EMP encountered by traditional cell culture systems. The findings are discussed with respect to cell membrane disturbances caused by EMP and its potential role as an early test of cytotoxicity.

Topics: Cell Line; Cell Membrane; Cell Survival; Colonic Neoplasms; Dose-Response Relationship, Drug; Estramustine; Glioma; Histological Techniques; Humans; Microscopy, Electron, Scanning; Rubidium Radioisotopes; Time Factors; Tumor Cells, Cultured

Thirty-five patients with advanced cancers were treated with estramustine phosphate tablets (Estracyt). Doses ranged between 420 mg and 700 mg daily. One partial response was documented in a hormone resistant prostatic cancer patient. Four minor responses (less than 50% responses, or less than one month more than 50% response) were obtained; one in a hormone resistant prostatic cancer, two in metastatic colorectal cancers; and another in a malignant melanoma. Toxicity phenomena included nausea (9/35 - 25%), water retention (4/35 - 11.5%) and mild elevation of alkaline phosphatase (2/35 - 6%). Other toxicity effects were vaginal bleeding in two women, acne in one woman and mild pruritus in another patient. Myelosuppression and immune suppression were not significantly detected.

Topics: Adult; Aged; Colonic Neoplasms; Drug Evaluation; Drug Resistance; Estramustine; Female; Humans; Male; Melanoma; Middle Aged; Neoplasms; Nitrogen Mustard Compounds; Prostatic Neoplasms; Rectal Neoplasms