stilbenes and anecortave-acetate

The aim of this study was to quantify tumor cell proliferation and growth, analyze tumor blood vessel development, and determine the efficacy of antiangiogenic and angiostatic therapy in targeting mature vessels in retinal tumors of the LH(BETA)T(AG) mouse model for retinoblastoma.. LH(BETA)T(AG) mouse retinas were analyzed at 4, 8, 12, and 16 weeks of age. Tumor burden was analyzed by histology; cell proliferation, vessel density, angiogenesis, and vessel maturation were detected by immunofluorescence. To assess the efficacy of mature vessel targeting, 16-week-old mice were treated with single subconjunctival injections of the selective vascular-targeting drug combretastatin A4 prodrug (CA4P) or anecortave acetate, and eyes were analyzed 1 day and 1 week after injection to determine microvessel density and the number of angiogenic and mature vessels.. Increased cell proliferation and angiogenesis were detected in the retinal inner nuclear layer (INL) before morphologic neoplastic changes were evident. As tumor size increased, angiogenesis diminished concomitantly with the appearance of mature vessels. Treatment with CA4P and anecortave acetate resulted in significant reductions in total vessel density. However, neither drug reduced the amount of alpha-smooth muscle actin (SMA)-positive, mature vessels.. Results of this study provide new insight into the relationship between tumor growth and blood vessel development in the LH(BETA)T(AG) mouse and establish the framework for defining the selective action of two vessel-targeting drugs against new blood vessels compared with mature blood vessels. These findings suggest a high potential value in targeting the process of angiogenesis in the treatment of children with retinoblastoma.

Topics: Actins; Angiogenesis Inhibitors; Animals; Antineoplastic Agents, Phytogenic; Bibenzyls; Biomarkers, Tumor; Cell Proliferation; Disease Models, Animal; Endoglin; Endothelium, Vascular; Intracellular Signaling Peptides and Proteins; Ki-67 Antigen; Mice; Mice, Transgenic; Microscopy, Fluorescence; Neovascularization, Pathologic; Pericytes; Pregnadienediols; Retinal Neoplasms; Retinoblastoma; Stilbenes

To evaluate the mechanism and timing of retinal tumor cell death in the LH(BETA)T(AG) mouse model of retinoblastoma after treatment with vascular targeting therapies and conventional therapies (focal chemotherapy and radiation).. For vascular targeting therapy, 12- or 16-week-old mice were treated with a single subconjunctival injection of either anecortave acetate (300 microg) or combretastatin A4 (1.5 mg). Eyes were analyzed at 1 day and 1 week after treatment. Tumor cell death was evaluated using TUNEL assays or immunofluorescence analysis of activated caspase 3 to detect apoptosis. Histopathologic analysis was performed to identify areas of necrosis. For conventional therapy, LH(BETA)T(AG) mice were treated with six serial subconjunctival injections of focally delivered carboplatin chemotherapy (100 microg/delivery) or hyperfractionated external beam radiotherapy (EBRT; 15 Gy total dose). Cell death was analyzed by TUNEL assay.. The highest levels of apoptotic cell death were seen 1 day after treatment in all treatment groups compared with vehicle controls. At 1 week after treatment, apoptotic cell death remained significantly elevated in the EBRT and carboplatin groups, but not after vessel targeting therapy. No significant necrosis was detected by histology in tumors of treated or of control eyes.. Conventional therapies (focal carboplatin chemotherapy and EBRT) and vascular targeting agents significantly increase cell death through apoptosis, while not having a significant effect on necrosis in this murine model of retinoblastoma. These studies will aid in the optimization of delivery schemes of combined treatment modalities.

Topics: Angiogenesis Inhibitors; Animals; Antineoplastic Agents; Apoptosis; Carboplatin; Caspase 3; Disease Models, Animal; Endothelium, Vascular; In Situ Nick-End Labeling; Mice; Mice, Transgenic; Neovascularization, Pathologic; Pregnadienediols; Radiotherapy, Conformal; Retinal Neoplasms; Retinoblastoma; Stilbenes; Time Factors