Synthetic retinoid shows activity against experimental neuroblastoma

Work in vitro and in rats suggests that the synthetic retinoid Ro 13-6307 may be useful in neuroblastoma therapy, Swedish researchers report in the May 1st issue of the International Journal of Cancer.

Dr. Frida Ponthan of the Karolinska Hospital, Stockholm, and colleagues note that retinoids modulate various functions in tumor cells and that 13-cis retinoic acid has been used clinically in children with neuroblastoma. However, “there is an ongoing effort to identify novel retinoids with improved potency and lower toxicity.”As part of that effort, the researchers compared the effects of Ro 13-6307 with those of 13-cis retinoic acid in neuroblastoma cells.They found that at a dose of 1 micromole, the synthetic retinoid decreased proliferation and accumulation of cells in “at least the same magnitude” as did 5 micromoles of 13-cis retinoic acid. No apoptosis was seen.Furthermore, nude rats with neuroblastoma xenografts, given 0.12 mg of Ro 13-6307 daily, showed decreased neuroblastoma volume during treatment and tumor weight after sacrifice. However, use of a 0.08-mg daily dosage resulted in no significant reduction in tumor growth.Rats treated with Ro 13-6307 gained less weight than controls but showed no other signs of toxicity. This was in contrast to findings in a previous study of such animals in which 0.3 mg of the agent prompted “severe toxic side effects.” Both of the tested agents showed a similar toxicity profile, and the researchers conclude that Ro 13-6307 “may be a candidate retinoid for clinical oral therapy of neuroblastoma in children.”(Source: Int J Cancer 2003; 104:418-424: Reuters Health: May 27, 2003: Oncolink)