Title: Hyperinducibility of hypoxia-responsive genes without p53/p21-dependent checkpoint in aggressive prostate cancer.
Authors: Salnikow, K; Costa, M; Figg, W D; Blagosklonny, M V
Published In Cancer Res, (2000 Oct 15)
Abstract: Hypoxia limits tumor growth but selects for higher metastatic potential. We tested the functional activity of hypoxia-inducible factor-1 (HIF-1) in prostate cell lines ranging from normal epithelial cells (PrEC), hormone-dependent LNCaP, hormone-independent DU145, PC-3 to highly metastatic PC-3M cancer cell lines. We found that HIF-1-stimulated transcription was the lowest in PrEC and LNCaP cells and the highest in PC-3M cells. The induction by hypoxia of the HIF-1 dependent genes Cap43 and GAPDH was the highest in the most aggressive PC-3M cancer cells. Because these advanced prostate cancer cell lines have lost p53 function, this further shifts a balance from p53 to HIF-1 transcriptional regulation, and a high ratio of HIF-1-dependent:p53-dependent transcription was a marker of the advanced malignant phenotype. Transient transfection of HIF-1alpha expression vector induced transcription from p21 promoter construct in prostate cancer cell lines. Furthermore, hypoxia slightly induced p21 mRNA in these cells. However, neither expression of p21 nor hypoxia caused growth arrest in PC-3M cells. Therefore, high inducibility of HIF-1-dependent genes, loss of p53 functions with high ratio of HIF-1-dependent:p53-dependent transcription, and loss of sensitivity to p21 inhibition is a part of hypoxic phenotype associated with aggressive cancer behavior.
PubMed ID: 11059752
MeSH Terms: Cell Cycle Proteins; Cell Cycle/genetics; Cell Hypoxia/genetics; Cyclin-Dependent Kinase Inhibitor p21; Cyclins/biosynthesis; Cyclins/genetics; Cyclins/physiology*; DNA-Binding Proteins/biosynthesis; DNA-Binding Proteins/genetics*; DNA-Binding Proteins/physiology; Flow Cytometry; Gene Expression Regulation, Neoplastic; Glyceraldehyde-3-Phosphate Dehydrogenases/genetics; Humans; Hypoxia-Inducible Factor 1; Hypoxia-Inducible Factor 1, alpha Subunit; Intracellular Signaling Peptides and Proteins; Male; Neoplasm Metastasis; Nuclear Proteins/biosynthesis; Nuclear Proteins/genetics*; Nuclear Proteins/physiology; Promoter Regions, Genetic/genetics; Prostatic Neoplasms/genetics*; Prostatic Neoplasms/metabolism; Prostatic Neoplasms/pathology; Protein Biosynthesis; Proteins/genetics; Transcription Factors/biosynthesis; Transcription Factors/genetics*; Transcription Factors/physiology; Transcription, Genetic/physiology; Transcriptional Activation/genetics; Tumor Cells, Cultured; Tumor Suppressor Protein p53/biosynthesis; Tumor Suppressor Protein p53/genetics; Tumor Suppressor Protein p53/physiology*