Pdgf-b Inducedbrain Tumors in Mice

Hypoxia-inducible factor 1 (hF-i) is a transcription factor that regu lates genes involved in adaptation to hypoxiL Expression of tifF-la wasevaluated in rat and human prostate cancer cell lines. Increased expression of HIF-la mRNA in rat prostate cancer cell lines and hypoxiainduced expression of HIF-la protein in human prostate cancer cell linesare associated with increased cell growth rates and metastatic potential.HIF-la mRNA was undetectable in the normal rat ventral prostate byNorthern blot hybridization. HIF-la protein expression and HIF-1 DNAbinding activity were detected in normoxic PC-3 cells. Human prostatecancer cells plated at low density manifested higher functional 11W-laexpression than cells plated at high density independent of °2 tension.HIF-la may become dysregulated in prostate cancer and thus drive thetranscription of hypoxia-adaptive genes involved in tumor progression.This is also the first evidence that human cancer cells can express functional HIF-la protein under normoxic conditions.