In vitro protection from cisplatin-induced neurotoxicity by amifostine and its metabolite WR1065

Cisplatin-induced neuropathy is a major dose-limiting toxicity. Counteraction by amifostine and its metabolite WR1065 may reduce peripheral neurotoxicity in a number of patients. Using the nerve growth factor (NGF)-dependent neurite outgrowth from the PC12 pheochromocytoma cell line as an in vitro assay for neurotoxicity, the protective effects of amifostine and WR1065 against cisplatin action on neurite formation by PC12 cells were studied. Cisplatin in a concentration of 10 μg/ml significantly decreased the percentage of neurite forming cells from 84% to 40%. Amifostine in doses of 0.4 and 0.8 mM proved to protect significantly against the cisplatin-induced decrease in neurite formation, when co-incubated with cisplatin. Also the metabolite WR1065 protected significantly against cisplatin neurotoxicity in a dose of 0.12 mM. Our results show a significant protection by amifostine and its main metabolite WR1065 against cisplatin-induced neurotoxicity using an in vitro model

Cytotoxicity and neurocytotoxicity of new marine anticancer agents evaluated using in vitro assays

Purpose: New classes of anticancer drugs, isolated from marine organisms, have been shown to possess cytotoxic activity against multiple tumor types. Aplidine, didemnin B, and isohomohalichondrin B (IHB), among the more promising antitumor candidates, have been evaluated in the present study on a comparative basis in terms of their antiproliferative activity and neurotoxic effects in vitro. Methods: Using a panel of different human, prostatic cancer cell lines (DU 145, PC-3 and LNCaP-FGC) the effects of Aplidine, didemnin B, and IHB on tumor cell proliferation were tested in a colorimetric (XTT) assay and compared with the effects of vincristine, vinorelbine, and Taxol. Under analogous in vitro conditions these drugs were also monitored for neurocytotoxic effects using a PC 12 cell line based model. Results: Didemnin B and - especially Aplidine were more effective in the inhibition of prostate cancer cell proliferation than vincristine, vinorelbine or Taxol at concentration levels between 5 and 50 pmol/ml. At these same concentrations, however, Didemnin B and Aplidine were also most potent in the in vitro neurotoxicity assays. IHB was found to exert even more potent antiproliferative activity (at concentration levels between 0.05 and 0.1 pmol/ml). However, neurotoxic effects were also found to be present at these levels. After drug withdrawal, the neurotoxic damage, inflicted by aplidine or IHB appeared to be more long lasting than after vincristine or vinorelbine exposure. Conclusions: These results point to high antiproliferative activity of aplidine and IHB in prostate cancer. At the same time, the data urge some caution in the clinical use of these agents because of potential neurotoxic side-effects. The use of a newly formulated Aplidine may involve a more favorable therapeutic profile

Radionuclide theraphy for prostate cancer lumbar metastasis prolongs symptom-free survival in a rat model

Objectives. The present study was initiated to explore the effects of hydroxyethylidene diphosphonate labeled with rhenium 186 (186Re-HEDP) treatment on the progression of lumbar skeletal metastasis in an animal model and to correlate the eventual treatment efficacy with the radioisotope tissue distribution. Methods. The effect of 186Re-HEDP on the progression of lumbar metastasis from prostate cancer was investigated in the Copenhagen rat model. Metastatic prostate tumor deposits were induced in male rats by tail vein injection of R3327-MATLyLu prostate tumor cells under concomitant clamping of the inferior caval vein. The development of clinical symptoms such as onset of hind leg paralysis and urinary bladder swelling was monitored and related to the presence of tumor cells within histologic sections of L-5 and L-6 vertebrae. Results. The 186Re-HEDP administration, given either 1 day or 8 days after surgical induction of lumbar metastasis, could significantly increase the symptom-free survival of the animals. These results were confirmed by a significant decrease in the presence of histologically detectable tumor tissue. Biodistribution studies demonstrated the uptake of the major part of the radioisotope within bone tissue. Uptake of radioactivity within the lumbar vertebrae on a microscopic scale, as shown by phosphor screen autoradiography, was concentrated in areas of bone formation and turnover. Signs of radiotoxicity, such as bone marrow replacement by fat cells and the absence of megakaryocytes, were observed. Conclusions. The results show that radionuclide treatment using 186Re- HEDP is a potentially efficacious treatment option in prostate cancer disseminated to the skeleton. The optimal treatment dose should be determined carefully and aimed at acceptable levels of myelotoxicity

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