The time for xenograft tumor formation was 6 ± 1.2 d for Eca109 cells and Eca109 cells transfected with HIF-1α Neo control short hairpin RNA (shRNA) vector, and 8.4 ± 2.1 d for Eca109 cells transfected with an shRNA against HIF-1α.
Furthermore, restoration of Nrf2 function in transformed cells decreased reactive oxygen species and impaired in vivo tumor growth (P = 0.001) by mechanisms that included sensitization to apoptosis, and a decreased hypoxic/angiogenic response through HIF-1α destabilization and VEGFA repression.
Flow cytometry, 5-ethynyl-2'-deoxyuridine (EdU) incorporation and tumor xenograft assay demonstrated that ZFP91 enhanced cell proliferation of colon cancer through upregulating HIF-1α in vitro and in vivo.
The tumor hypoxia changes induced after bevacizumab treatment were evaluated using optical imaging with a HIF-1-dependent reporter gene using the NCI-H441 human lung adenocarcinoma xenograft model.
The combination therapy with antisense HIF-1alpha and doxorubicin was more effective in suppressing tumor growth, angiogenesis, and cell proliferation, and inducing cell apoptosis than the respective monotherapies.
Our findings suggest that hypericin may potentially be useful in preventing growth of tumors in which HIF-1α plays pivotal roles, and in pVHL ablated tumor cells such as renal cell carcinoma through elimination of elevated HIF-1α contents in these cells, scaling down the excessive angiogenesis which characterizes these tumors.
Under hypoxia, HIF-1α directs glucose away from mitochondria, leaving Tregs dependent on fatty acids for mitochondrial metabolism within the hypoxic tumor.
In line with these observations, here we demonstrate the influence of LDR in down-modulating HIF-1 in irradiated tumors in the course of polarization of irradiated tumor-associated macrophages toward an M1 phenotype.
However, recent studies have indicated that in this setting, upregulation of the closely related HIF-alpha isoforms, HIF-1alpha and HIF-2alpha, have contrasting effects on tumour growth, and activate distinct sets of target genes.
Tumors' expression of p53, VEGF, Ki-67, and HIF-1alpha was compared based on ethnicity and tumor type (Type I = endometrioid carcinomas and Type II = non-endometrioid carcinomas).
These data suggest that TRPM2 activity is important for tumor growth and for cell viability and survival following doxorubicin treatment and that interference with TRPM2-L function may be a novel approach to reduce tumor growth through modulation of HIF-1/2α, mitochondrial function, and mitophagy.
In some tumors such as renal cell carcinoma, the EGLN/HIF axis appears to drive tumorigenesis, while in many others HIF1 and HIF2 may actually have a tumor suppressive role.
Although its activation benefits normal tissue, HIF-1 activation in tumors is a major risk factor for angiogenesis, therapeutic resistance, and poor prognosis.
The VHL gene is a putative tumour suppressor gene in VHL and a few other conditions, possibly by negative regulation of hypoxia- inducible factor-1 (HIF-1) and the stromal-derived factor-1 (SDF-1) receptor, CXCR4, via which the VHL protein negates angiogenesis and tumour cell migration.
In an attempt to elucidate the relationship between biomarkers of tumor hypoxia, glycolysis and angiogenesis, we tested the hypothesis that intratumoral gene expression of the hypoxia response (hypoxia inducible factor [HIF1 alpha and 2 alpha]), glycolysis (lactate dehydrogenase A [LDHA]), glucose metabolism (glucose transporter-1 [Glut-1]) and genes involved in angiogenesis (i.e., VEGFA, VEGFR1-3, and neuropilin [NRP]1) are upregulated in metastatic colorectal cancer (mCRC) patients with high serum lactate dehydrogenase (LDH).
The activation of the transcription factor hypoxia-inducible factor-1 (HIF-1) plays an essential role in tumor development, tumor progression, and resistance to chemo- and radiotherapy.
Further understanding of the microtubule-dependent HIF-1α regulation, and lack thereof in RCC, is essential given the importance of HIF-1α in tumor biology, and the widespread use of MTDs in clinical oncology.
Our findings provide novel insights for a better understanding of HIF-1α and mTOR in the tumor biology of HNSCC and their interaction with selective small-molecule inhibitors.
Finally, the anti-tumor effect of HIF-1α knockdown (KD) plus GI was evaluated using a tumor xenograft model, where a hypoxic environment naturally exists.