Hypoxia-inducible factor-1alpha is a key regulator of metastasis in a transgenic model of cancer initiation and progression.
Adaptation to hypoxia is a critical step in tumor progression and is, in part, regulated by the transcription factor hypoxia-inducible factor-1alpha (HIF-1alpha). Xenograft models have been extensively used to characterize the role of HIF-1alpha in experimental cancers. Although these models provide an understanding of tumor growth at terminal stages of malignancy, they do not address tumor initiation or metastatic progression. To elucidate these roles, HIF-1alpha was conditionally deleted in the mammary epithelium of a transgenic mouse model for metastatic breast cancer. Conditional deletion of HIF-1alpha in the mammary epithelium resulted in delayed tumor onset and retarded tumor growth; this was correlated with decreased tumor cell proliferation. Tumors with conditional deletion of HIF-1alpha were also less vascular during early tumor progression. Perhaps most surprisingly, deletion of HIF-1alpha in the mammary epithelium resulted in decreased pulmonary metastasis. These results show that whereas HIF-1alpha is not required for the initiation of breast tumor growth or tumor cell metastasis, the transcriptional activity of HIF-1alpha is a significant positive regulator of tumor progression and metastatic potential.
Liao
Debbie
D
Division of Biological Sciences, Molecular Biology Section, and Department of Molecular Pathology, School of Medicine, University of California, San Diego, La Jolla, California 92093-0377, USA.
Corle
Courtney
C
Seagroves
Tiffany N
TN
Johnson
Randall S
RS
D000818:Animals; D048708:Cell Growth Processes / Q000502:physiology; D018450:Disease Progression; D005260:Female; D006965:Hyperplasia; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D008175:Lung Neoplasms / Q000556:secondary; D008297:Male; D015674:Mammary Neoplasms, Animal / Q000473:pathology; D008325:Mammary Neoplasms, Experimental / Q000098:blood supply / Q000473:pathology*; D051379:Mice; D018345:Mice, Knockout; D008822:Mice, Transgenic; D009362:Neoplasm Metastasis; D014158:Transcription, Genetic
D051795:Hypoxia-Inducible Factor 1, alpha Subunit