o-(chloroacetylcarbamoyl)fumagillol and Necrosis

Potential anticancer therapy with the fumagillin analog TNP-470 was investigated in the present project using subcutaneously growing rhabdomyosarcomas in rats. Specifically, influences of different tumor sizes at the start of treatment as well as dose/schedules were evaluated with this angiogenesis inhibitor. The results show a significant (p = < or = 0.01) reduction of the growth rate, even for relatively large-sized (> 7 cm3) tumors, when 50 mg/kg TNP-470 was used every other day for up to 3 or 5 injections. With 30 mg/kg TNP-470 injections, effects were seen only with tumors measuring < 7 cm3. The histologic examinations demonstrate an increase in necrosis, both in the center and in the peripheral part of TNP-470-treated tumors. Overall, both tumor volume and drug dose determine treatment outcome with the rat rhabdomyosarcoma. The results suggest that angiogenesis inhibitors could represent a valid component in the treatment of progressive tumor growth, also of large tumors as often encountered in clinics. The antivasculature therapy might also improve hypoxia/necrosis-related therapeutic approaches.

Topics: Angiogenesis Inhibitors; Animals; Cell Survival; Cyclohexanes; Drug Administration Schedule; Male; Necrosis; O-(Chloroacetylcarbamoyl)fumagillol; Rats; Rhabdomyosarcoma; Sesquiterpenes

We examined the mechanism of the reduction of metastatic liver tumors in rats treated with angiogenesis inhibitor TNP-470 on the histological basis of patterns of tumor cell death. Metastatic tumors were developed by intravenous injection of AH-130 cell line, followed by a dose of TNP-470. Alteration in the size and number of metastatic liver tumors and its cell death pattern were analyzed. The number and size of the metastatic tumors at 2 weeks in untreated rats were larger than those in treated rats. The number of tumors in untreated rats decreased, whereas their size increased. All rats treated were alive and free from tumors after 4 weeks, although all untreated rats died of metastatic tumors. Necrosis was predominant in the tumors of untreated rats, while most tumors in treated rats showed apoptosis. Consequently, the metastatic tumor in untreated rats might grow faster than its angiogenesis, suggesting the occurrence of central necrosis due to apparent ischemia. On the other hand, the tumor in treated rats might be reduce a by weak ischemic stimulus, which triggers apoptosis.

Topics: Animals; Antibiotics, Antineoplastic; Apoptosis; Cell Division; Cyclohexanes; Liver Neoplasms; Necrosis; Neoplasm Transplantation; Neovascularization, Pathologic; O-(Chloroacetylcarbamoyl)fumagillol; Rats; Sesquiterpenes

To clarify the mechanism of the reduction of metastatic liver tumors in rats treated with angiogenesis inhibitor TNP-470, the death of tumor cells was examined pathologically and ultrastructurally. Liver metastases were developed by intravenous injection of AH-130 cells. TNP-470 was given subcutaneously after tumor cell injection. Alterations in the size and number of metastatic tumors were examined at various time points, in association with the analysis of cell death pattern. The metastatic nodules were divided into 4 groups according to the morphological patterns of cell death; no cell death, scattered apoptosis, central necrosis, and diffuse necrosis. The number and size of the metastatic tumors at 2 weeks in untreated rats were larger than those in treated rats. The number of tumors in untreated rats decreased, but the tumor size increased. All rats treated with TNP-470 were alive and free from tumors after 4 weeks, whereas all the untreated rats died of liver metastases. The percentages of the tumors with necrosis in untreated rats (61.2% at 2 weeks and 100% at 4 weeks) were significantly higher than that (31.8% at 2 weeks) in treated rats (P < 0.01). The percentage of the tumors containing apoptotic cells in treated rats was significantly higher than that in untreated rats (54.5% vs. 30.6%; P < 0.05). The growth of metastatic tumors without treatment might be faster than the growth of vessels in untreated tumors, resulting in central necrosis due to ischemia. On the other hand, the reduction of metastatic liver tumors treated with TNP-470 might be caused by inhibition of angiogenesis, providing a weak ischemic stimulus which triggers apoptosis, rather than by a direct cytotoxic effect on tumor cells, because previous in vivo experiments demonstrated that TNP-470 affected endothelial cells but not tumor cells.

Topics: Animals; Antibiotics, Antineoplastic; Apoptosis; Cyclohexanes; Liver; Liver Neoplasms; Male; Microscopy, Electron; Necrosis; Neoplasm Transplantation; Neovascularization, Pathologic; O-(Chloroacetylcarbamoyl)fumagillol; Rats; Rats, Inbred Strains; Remission Induction; Sesquiterpenes; Tumor Cells, Cultured