Related Experiment Video
Updated: Jun 9, 2026
Co-immunoprecipitation Assay Using Endogenous Nuclear Proteins from Cells Cultured Under Hypoxic Conditions
Published on: August 2, 2018
Hypoxia inducible factor 1α and hypoxia inducible factor 2α play distinct and functionally overlapping roles in oral
Gui-quan Zhu1, Ya-ling Tang, Ling Li
1West China Hospital of Stomatology, Sichuan University, Chengdu, China.
Purpose:
This study aimed to investigate the functional difference between hypoxia inducible factor (HIF)-1α and HIF-2α in oral squamous cell carcinomas (OSCC).
Experimental Design:
We evaluated the correlations between HIF-1α and HIF-2α expression and the clinical-pathologic characteristics of 97 patients with OSCC by immunohistochemical staining. OSCC cell lines transfected with lentivirus encoding short hairpin RNA against HIF-1α/2α were used to investigate the HIF-1α/2α-dependent target genes. Xenograft tumors in nude mice were established using cells affected by lentivirus, and tumor growth, angiogenesis, proliferation, and apoptosis were measured.
Results:
HIF-1α expression was significantly associated with T stage (P = 0.004), lymph node involvement (P = 0.006), histologic differentiation (P = 0.013), and microvessel density (P = 0.014), whereas that of HIF-2α was associated with T stage (P = 0.011) and microvessel density (P = 0.005). Patients with positive HIF-1α nuclear staining had a significantly worse overall survival (P < 0.001) and disease-free survival (P < 0.001) than those with negative HIF-1α staining. When OSCC cells were cultured at 5% O(2), only HIF-2α contributed to the expression of vascular endothelial growth factor. At 1% O(2), vascular endothelial growth factor was regulated by both HIF-1α and HIF-2α, but glucose transporter 1, carbonic anhydrase 9, and urokinase-type plasminogen activator receptor were regulated by HIF-1α rather than by HIF-2α. Knocking down HIF-1α or HIF-2α individually inhibited the xenograft tumor angiogenesis and growth, and knocking them down simultaneously revealed a better inhibitory effect than knocking down either unit alone.
Conclusions:
HIF-1α and HIF-2α correlated with different clinical-pathologic parameters, stabilized at different oxygen levels, and regulated different genes in OSCC. However, both HIF-1α and HIF-2α showed promoting roles in tumor angiogenesis and growth, and therapeutic outcome may benefit from combined targeting of HIF-1α and HIF-2α.
Related Concept Videos
02:53Adaptive Mechanisms in Cancer Cells
Some of the advantages that cancer cells have on normal cells include - enhanced ability to divide without terminally differentiating, induce new blood vessel formation,...
02:53Adaptive Mechanisms in Cancer Cells
Some of the advantages that cancer cells have on normal cells include - enhanced ability to divide without terminally differentiating, induce new blood vessel formation,...
01:24Regulation of Angiogenesis and Blood Supply
01:30General Transcription Factors
02:49Cancer Therapies
However, cancer treatments can pose several challenges, as therapies used to kill cancer cells are generally also toxic to normal cells. Moreover, cancer cells mutate rapidly and can develop resistance to chemical agents or radiation therapy. Besides, all types of cancer cells may not respond to the same therapy. Some cancer cells respond to one...
01:05Cancer-Critical Genes II: Tumor Suppressor Genes
When the function of certain critical genes, especially those involved in cell cycle regulation and cell growth signaling cascades, gets disrupted, it upsets the cell cycle progression. Such cells with unchecked cell cycles start proliferating uncontrollably and eventually develop into tumors.
Such genes that act...