The role of constitutive NF-kappaB activity in PC-3 human prostate cancer cell invasive behavior.
The purpose of this study was to determine if increased NF-kappaB activity of highly invasive PC-3 cells contributed to their invasive behavior. Increased NF-kappaB activity has been observed in several malignant tumors and it may have an important role in tumorigenesis, progression and chemotherapy resistance. By serial selection, we obtained invasion variant PC-3 cell sublines. The PC-3 High Invasive cells invade readily through a Matrigel reconstituted basement membrane while PC-3 Low Invasive cells have low baseline invasion activity. In these studies, we discovered that NF-kappaB DNA binding activity was increased in PC-3 High Invasive cells when compared to PC-3 Low Invasive cells by electrophoretic mobility shift assay (EMSA). Gel supershift assays showed a 4-fold increase in p65 containing complexes and a 2.2-fold increase in the p50 containing complexes in the PC-3 High Invasive cells. Luciferase reporter assays showed that NF-kappaB dependent transcription activity was increased 10.2 +/- 2.5-fold in the highly invasive cells (P < 0.002). The PC-3 High Invasive cells showed a constitutive increase in phospho-IkappaB alpha and introduction of the super-repressor IkappaB alpha S32/36A inhibited NF-kappaB activity to 19.2 +/- 2.5 percent of control transfected cells (P < or = 0.001). The IkappaBa super-repressor reduced the basement membrane invasion of PC-3 High Invasive cells from 6.2 +/- 1.1 to 3.8 +/- 0.4 percent (P < 0.002) with no decrease in cell viability or proliferation. These results demonstrate that increased NF-kappaB activity contributed directly to the invasive behavior of PC-3 High Invasive prostate cancer cells.
Lindholm
P F
PF
Department of Laboratory Medicine and Pathology, Medical College of Wisconsin, Milwaukee 53226, USA.
Bub
J
J
Kaul
S
S
Shidham
V B
VB
Kajdacsy-Balla
A
A
D001483:Base Sequence; D015153:Blotting, Western; D002455:Cell Division; D017931:DNA Primers; D017930:Genes, Reporter; D006801:Humans; D008156:Luciferases / Q000235:genetics; D008297:Male; D016328:NF-kappa B / Q000502:physiology*; D009361:Neoplasm Invasiveness; D010641:Phenotype; D011471:Prostatic Neoplasms / Q000473:pathology* / Q000503:physiopathology*; D014407:Tumor Cells, Cultured
D017931:DNA Primers; D016328:NF-kappa B; D008156:Luciferases