Increased expression of hypoxia inducible factor-1 alpha in rat and human prostate cancer

Hypoxia-inducible factor 1 (HIF-1) is a transcription factor that regulates genes involved in adaptation to hypoxia, Expression of HLF-1 alpha was eva luated in rat and human prostate cancer cell lines. Increased expression of HIF-1 alpha mRNA in rat prostate cancer cell lines and hypoxia-induced exp ression of HIF-1 alpha protein in human prostate cancer cell lines are asso ciated with increased cell growth rates and metastatic potential. HIF-1 alp ha mRNA mas undetectable in the normal rat ventral prostate hy Northern blo t hybridization. HIF-1 alpha protein expression and HIF-1 DNA binding activ ity were detected in normoxic PC3 cells. Human prostate cancer cells plated at low density manifested higher functional HIF-1 alpha expression than ce lls plated at high density independent of O-2 tension. HIF-1 alpha may beco me dysregulated in prostate cancer and thus drive the transcription of hypo xia-adaptive genes involved in tumor progression. This is also the first ev idence that human cancer cells can express functional HIF-1 alpha protein u nder normoxic conditions.