ANTINEOPLASTIC EFFECT OF 1,25-DIHYDROXY-16-ENE-23-YNE-VITAMIN-D-3 ANALOG IN TRANSGENIC MICE WITH RETINOBLASTOMA

Objective: To evaluate the in vivo efficacy and clinical toxic effects of the 1,25-dihydroxy-16-ene-23-yne-vitamin D-3 analogue in beta-lute inizing hormone-Tag (LH beta-Tag) transgenic mice with heritable retin oblastoma. Methods: Forty-two mice (8-10 weeks old), randomly assigned to experimental (n=21) ar control (n=21) groups, received intraperito neal injections of 0.05 mu g of 1,25-dihydroxy-16-ene-23-yne-D-3 in 0. 5-mL mineral ail vehicle (experimental group) or 0.5 mL of mineral ail vehicle (control group) for 5 weeks. One experimental and a control a nimals died of injection-related trauma. Eyes were: enucleated 1 week after treatment and were examined histologically in a masked fashion. Results: All experimental and control animals showed evidence of tumor . The tumours in the experimental mice showed a significantly smaller cross-sectional area (0.88 +/- 0.08 mm(2)) compared with that in the c ontrol mice (1.12 +/- 0.12 mm(2)) (P=.02). All mice completed the trea tment and showed no clinical evidence of toxic effects. Conclusions: T umors in transgenic mice with retinoblastoma treated with 1,25(OH)(2)- 16-ene-23-yne-D-3 showed a 21% smaller cross-sectional area compared w ith that in the control mice, without producing clinically apparent to xide effects, This compound may be useful as adjunctive therapy in the treatment of retinoblastoma.