o-(chloroacetylcarbamoyl)fumagillol and Rhabdomyosarcoma

Interference with the tumor blood vessels through anti-angiogenesis or vascular targeting can indirectly suppress tumor growth. Vascular targeting of solid tumors, using tubulin-compromising agents, seems a promising and selective novel treatment. We aimed to evaluate the potential (hypothesis-based) benefit from combinations of vascular targeting using combretastatin A-4 phosphate (combreAp) with either ionizing radiation or anti-angiogenesis.. Rhabdomyosarcoma tumor pieces were inplanted subcutaneously (s.c.) in the lower flank region of syngeneic adult WAG/Rij rats. Tumors were grown until different sizes and stratified for the various treatment groups: small (1-3 cm3), medium (3.1-7 cm3), and large (7.1-14 cm3). CombreAp was injected i.p.; injections of TNP-470 were s.c. in the neck area. Localized single-dose (8 Gy) irradiations of tumors were done under Nembutal anesthesia, always 1 day before a single combreAp (25 mg/kg) injection. The TNP-470 treatment (3 times 30 mg/kg in 1 week) started 1 day after a double (8 days interval between both) combreAp administration. Tumor responses were evaluated by the growth delay assay, and statistical significance of tumor growth change was computed.. Large tumors responded better to combreAp treatment given alone than did the smaller ones, confirming our previous data with this tumor model. Combining irradiation with combreAp also resulted in a tumor size-dependent growth delay. With small and medium tumor volumes, a similar response was measured after the combination treatment when compared with irradiation only. Large tumors, however, showed a strong (at least additive) increase of the growth delay with the combined therapy; the difference in tumor growth between the two treatment groups was very significant (p < 0.0001). m When TNP-470 was combined with combreAp, no significant lengthening of the growth delay, irrespective of the tumor size, was present with the applied schedule.. The current data show a significant advantage in the combination of combreAp with irradiation in rhabdomyosarcomas having a large size (7-14 cm3) at treatment. Such a benefit in tumor response was not observed with the smaller tumors, seemingly because irradiation as such was very effective. No significant gain in growth delay for any tumor size was observed when TNP-470, showing efficacy on its own specifically with tumors measuring <7 cm3, was added to the combreAp treatment. This presumably reflects only little angiogenesis during the first week of rhabdomyosarcoma regrowth after the combreAp treatment.

Topics: Angiogenesis Inhibitors; Animals; Antineoplastic Agents, Phytogenic; Combined Modality Therapy; Cyclohexanes; Drug Screening Assays, Antitumor; Humans; O-(Chloroacetylcarbamoyl)fumagillol; Radiotherapy Dosage; Rats; Rhabdomyosarcoma; Sesquiterpenes; Stilbenes; Transplantation, Heterologous

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

The purpose of our study was to investigate a novel therapeutic approach for rhabdomyosarcoma (RMS) in an animal model. The pursuit of new therapeutic modalities for RMS is critically important since this type of tumor is the most common soft tissue sarcoma in children and because patients with metastatic disease may not be cured with current therapeutic modalities. We studied whether RMS growth may be suppressed by TNP-470, an analog of fumagillin, which was found to inhibit neoangiogenesis. Our data had shown that animals treated with TNP-470 (60 mg/kg), over a specific period of time, had approximately 50% smaller tumors than controls. Consistent with previous observations, treatment with TNP-470 decreases the level of the cyclin D1. Tumors dissected from TNP-470-treated animals had also considerable necrotic areas. In addition, TNP-470 had a direct cytotoxic effect on RMS cells in vitro. Our study has shown, therefore, that RMS in an animal model and in vitro responds to treatment with TNP-470, which suggests that the inhibitors of angiogenesis may be useful in a novel therapeutic design for RMS.

Topics: Animals; Antibiotics, Antineoplastic; Cell Division; Cyclohexanes; Humans; Mice; Mice, Nude; Neoplasm Transplantation; Neoplasms, Experimental; O-(Chloroacetylcarbamoyl)fumagillol; Rhabdomyosarcoma; Sesquiterpenes