Prevention of metastasis of intraocular melanoma in mice treated with difluoromethylornithine

Mouse models of uveal melanoma: Strengths, weaknesses, and future directions

Uveal melanoma is the most common primary malignancy of the eye, and a number of discoveries in the last decade have led to a more thorough molecular characterization of this cancer. However, the prognosis remains dismal for patients with metastases, and there is an urgent need to identify treatments that are effective for this stage of disease. Animal models are important tools for preclinical studies of uveal melanoma. A variety of models exist, and they have specific advantages, disadvantages, and applications. In this review article, these differences are explored in detail, and ideas for new models that might overcome current challenges are proposed.

Adjuvant intra-arterial hepatic fotemustine for high-risk uveal melanoma patients

Uveal melanoma metastases occur most commonly in the liver. Given the 50% mortality rate in patients at high risk of developing liver metastases, we tested an adjuvant intra-arterial hepatic (i.a.h.) chemotherapy with fotemustine after proton beam irradiation of the primary tumour. We treated 22 high-risk patients with adjuvant i.a.h. fotemustine. Planned treatment duration was 6 months, starting with four weekly doses of 100 mg/m(2), and after a 5-week rest, repeated every 3 weeks. The survival of this patient group was compared with that of a 3 : 1 matched control group randomly selected from our institutional database. Half of the patients experienced > or =grade 3 hepatotoxicity (one patient developing cholangitis 8 years later). Catheter-related complications occurred in 18%. With a median follow-up of 4.6 years for the fotemustine group and 8.5 years for the control group, median overall survival was 9 years [95% confidence interval (CI) 2.2-12.7] and 7.4 years (95% CI 5.4-12.7; P=0.5), respectively, with 5-year survival rates of 75 and 56%. Treatment with adjuvant i.a.h. fotemustine is feasible. However, toxicities are important. Although our data suggest a survival benefit, it was not statistically significant. Confirming such a benefit would require a large, internationally coordinated, prospective randomized trial.

Melanoma chemoprevention

BACKGROUND

Despite efforts to promote sun protection behaviors, melanoma incidence continues to increase. The prognosis of advanced melanoma remains extremely poor in spite of treatment advances, emphasizing the importance of exploring additional preventive measures.

OBJECTIVE

We sought to summarize the results of published research on candidate chemoprevention agents for melanoma.

METHODS

We conducted a narrative review of the literature.

RESULTS

Investigation into a possible role in melanoma chemoprevention continues for multiple agents, including sunscreen, lipid-lowering medications, nonsteroidal anti-inflammatory drugs, dietary nutrients, immunomodulators, and other drugs, including retinoids, difluoromethylornithine, and T4 endonuclease V.

LIMITATIONS

Systematic review of the literature was not performed.

CONCLUSION

Because no agent yet emerges as a clear choice for effective melanoma chemoprevention, sun avoidance and sun protection remain the mainstay of melanoma prevention for persons at high risk.

Animal models in uveal melanoma: establishment and research

Experimental models may help elucidate aspects of uveal melanoma, such as the histogenesis, etiology and natural history, that are not yet fully understood. Moreover, the development of experimental models allows testing of new diagnostic methods and treatments to improve the life expectancy and quality of life of affected patients. The author reviews the development of animal models of uveal melanoma and research with animal models examining primary and metastatic uveal melanoma as well as treatments for these tumours and ways to prevent metastasis.

Effect of anti-ganglioside antibodies on the metastatic spread of intraocular melanomas in a nude mouse model of human uveal melanoma

In vivo and in vitro studies were performed to determine: (a) if human uveal melanoma cells expressed GD2 and GD3 gangliosides; (b) if anti-GD2 monoclonal antibodies would inhibit the propensity of human uveal melanoma cells to localize in the liver following intravenous injection; and (c) if anti-GD2 monoclonal antibody would reduce the spontaneous metastasis of primary intraocular melanomas in nude mice. The results showed that all three of the human uveal melanoma cell lines tested expressed GD2 and GD3 gangliosides in vitro and in vivo. The human uveal melanoma cell lines preferentially localized in the liver and entered the hepatic parenchyma following spontaneous metastasis from the eyes of nude mice. In vivo administration of anti-GD2 monoclonal antibody produced a sharp reduction in the number of uveal melanoma cells that disseminated to the liver following either intravenous injection or by spontaneous metastasis from primary intraocular melanomas. Collectively, the results demonstrate that uveal melanoma cells display a propensity to localize in the liver after entering the bloodstream; however, this localization can be significantly inhibited by in vivo administration of anti-ganglioside antibodies. The expression of GD2 and GD3 surface gangliosides on uveal melanomas and the capacity of anti-ganglioside antibodies to inhibit metastasis formation in mouse models of ocular and cutaneous melanomas raise the possibility of implementing anti-ganglioside antibodies as potential therapeutic agents for the management of uveal melanoma.