Background: Therapy with 5-fluorouracil (5-FU) and capecitabine is often complicated by skin toxicity (hand-foot syndrome, HFS). Topical application of uridine ointment is beneficial for alleviating HFS and other pyrimidine nucleosides have been described as 5-FU toxicity modulators.
We tested pyrimidine nucleosides and their combinations to find the best combination for topical therapy of HFS. Materials and Methods: Cellular viability was measured by the real-time cell analyser and methyl thiazol tetrazolium (MTT) assay in order to evaluate the effect of pyrimidine nucleosides on HaCaT keratinocytes treated with 5-FU.
The results were confirmed by evaluation of the cellular colonization by microphotography. Results: Cytidine and uridine protected keratinocytes to the same extent.
Thymidine enhanced the protective effect when added to cytidine or uridine. Deoxycytidine did not have any protective effect.
Conclusion: Our findings support the rationale for using uridine or cytidine in combination with thymidine in ointment for HFS treatment.