Effect of platelet activating factor and butyrate on the expression of interleukin-2 receptor alpha in nasopharyngeal carcinoma cells

Serum level of soluble interleukin-2 receptor alpha (sIL-2R alpha) has been shown to correlate with disease progression and prognosis of cancer patien ts. However, the available information about the source and the pathophysio logical regulation of IL-2R alpha in cancer cells is limited. This study ad dressed the questions of prognostic value and the source of sIL-2R alpha in patients with nasopharyngeal carcinoma (NPC). Biological regulation of IL- 2R alpha was characterized in NPC cell lines. Serum sIL-2R alpha levels of 113 NPC patients were measured by enzyme-linked immunosorbent assay (ELISA) . Levels of sIL-2R alpha in NPC patients were significantly higher than tha t in the healthy controls, and sIL-2R alpha levels were correlated with dis ease progression and patient survival IL-2R alpha was identified in cancer cells by immunocytochemistry. In vitro, IL-2R alpha expression was markedly increased following treatment with platelet activating factor and/or n-sod ium butyrate. Increased secretion of IL-2R alpha was also detected in the c ulture media. The secreted IL-2R alpha could functionally bind IL-2. These results indicate that elevated sIL-2R alpha was often detected in patients with advanced NPC. The elevated sIL-2R alpha could be shed from NPC cells b y a yet to be determined mechanism and IL-2R alpha expression in NPC cells could be upregulated by platelet activating factor and butyrate.