Effects of hypoxia and NO on the expression of HIF-1?, VEGF and iNOS in colon cancer cells SW480 / 中国病理生理杂志

ABSTRACT

AIM: To observe the expression of HIF-1? mRNA, HIF-1?, VEGF and iNOS proteins and to investigate their relationship in h ypoxia-treated SW480 cells. METHODS: HIF-1?, VEGF and iNOS proteins were measured by immuno cytochemistry. Western-blot was used to detect HIF-1? protein. HIF-1? mRNA wa s measured by in situ hybridization. RESULTS: Under hypoxic condition, SW480 cells expressed proteins of HIF-1?, VEGF and iNOS more strongly than that under normoxia condition. How e ver, under hypoxia condition, these three proteins expressed weakly or negativel y when the cells treated with genistein, the inhibitor of HIF-1?. Expressions o f HIF-1? and VEGF proteins in cultured SW480 cells under hypoxic condition were completely or partially inhibited by the addition of SNP but the expression of iNOS was unaffected. Another NO donor NOC5, however, induced the expression of t hese three proteins. L-NAME, a non-specific inhibitor of NOS, inhibited the expr ession of HIF-1?, VEGF and iNOS. The levels of HIF-1? mRNA changed slightly i n different oxygen condition or addition of genistein, NO donor or iNOS inhibitor . CONCLUSIONS: Hypoxia induces the expression of HIF-1?, therefor e upregulates the production of VEGF and iNOS. During hypoxia, SNP inhibits but N OC5 promotes HIF-1? expression, indicating that different NO donor acts on the cells through different mechanisms.