An in vivo model of melanoma: treatment with ATP.

Athymic mice, injected with A375 human melanoma cells, were treated daily with intraperitoneal injections of adenosine 5'-triphosphate (ATP). The tumour volume and animal weight were measured over the course of the experiment and the final tumour nodule weight was measured at the end of the experiment. Tumour volume decreased by nearly 50% by 7 weeks in treated mice. Weight loss in untreated animals was prevented by ATP. Histological examination of the excised tumour nodules showed necrosis in the ATP-treated tumours only. The presence of P2Y(1) and P2X(7) receptors, previously proposed as extracellular targets for melanoma treatment with ATP, were demonstrated in the excised specimens by immunohistochemistry. This paper provides further support for the use of ATP as a treatment for melanoma.