Validating potential targets is an important step in the drug discovery process. In this study, we tested the feasibility of using inducible RNA interference (RNAi) in vivo to obtain an unbiased evaluation on the efficacy of inhibiting hypoxia-inducible factor-1alpha (HIF-1alpha) in established tumors. We showed that HIF-1alpha inhibition resulted in transient tumor stasis or tumor regression, and inhibiting HIF-1alpha in early-stage tumors was found to be more efficacious than inhibiting HIF-1alpha in more established tumors. A differential requirement of HIF-1alpha for tumor growth was also observed among different tumor types. Examination of tumors resistant to HIF-1alpha inhibition suggested that the resistance might result from a less hypoxic tumor environment and the level of HIF-1alpha expression in tumors may be a useful marker for predicting tumor response to HIF-1 inhibition. This study shows that inducible RNAi is a versatile tool for evaluating cancer targets in vivo. In addition to broad implications on in vivo validation of cancer targets, results from this study will also be instructive for practical applications of HIF-1-based cancer therapeutics.
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http://dx.doi.org/10.1158/0008-5472.CAN-04-4426 | DOI Listing |
BMC Cancer
January 2025
Shaanxi Engineering Research Center of Cell Immunology, Shaanxi Provincial People's Hospital, Xi'an, Shaanxi, China.
Background: Triple-negative breast cancer (TNBC) is among the most aggressive forms of breast cancer, characterized by a dismal prognosis. In the absence of drug-targetable receptors, chemotherapy remains the sole systemic treatment alternative. Recent advancements in immunotherapy, particularly immune checkpoint inhibitors (ICIs) that target programmed death 1/programmed death ligand 1 (PD-1/PD-L1) and cytotoxic T lymphocyte associated antigen 4 (CTLA-4), have provided renewed optimism for the treatment of patients with TNBC.
View Article and Find Full Text PDFNat Metab
January 2025
State Key Laboratory of Natural Medicines, School of Life Science and Technology, China Pharmaceutical University, Nanjing, China.
Nucleotide availability is crucial for DNA replication and repair; however, the coordinating mechanisms in vivo remain unclear. Here, we show that the circadian clock in the liver controls the activity of the pentose phosphate pathway (PPP) to support de novo nucleotide biosynthesis for DNA synthesis demands. We demonstrate that disrupting the hepatic clock by genetic manipulation or mistimed feeding impairs PPP activity in male mice, leading to nucleotide imbalance.
View Article and Find Full Text PDFInt J Mol Sci
December 2024
Centre for Diabetes, Obesity and Endocrinology (CDOE), The Westmead Institute for Medical Research, The University of Sydney, Sydney, NSW 2145, Australia.
Type 1 diabetes (T1D) is caused by the immune-mediated loss of pancreatic β-cells. Hypoxia-inducible factor 1α (HIF-1α) is a transcription factor which is crucial for cellular responses to low oxygen. Here, we investigate the role of β-cell HIF-1α in β-cell death and diabetes after exposure to multiple low-dose streptozotocin (MLDS).
View Article and Find Full Text PDFBiomedicines
December 2024
Institute of Pathological Physiology, Faculty of Medicine, University of Belgrade, Dr Subotića 1, 11000 Belgrade, Serbia.
Background/objectives: Chronic kidney disease (CKD) is a progressive pathological condition which results in the severe fibrosis of the kidneys. However, the mechanisms of CKD progression and fibrogenesis remain unclear. We wanted to examine the effects that apocynin and hyperbaric oxygen therapy (HBOT) have on renal function and structure in animals with CKD induced through 5/6 nephrectomy (5/6 Nx-L).
View Article and Find Full Text PDFBiomolecules
December 2024
Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, TX 77204, USA.
HIF-1α plays a crucial regulatory role in vascular calcification (VC), primarily influencing the osteogenic differentiation of VSMCs through oxygen-sensing mechanisms. Under hypoxic conditions, the stability of HIF-1α increases, avoiding PHD and VHL protein-mediated degradation, which promotes its accumulation in cells and then activates gene expressions related to calcification. Additionally, HIF-1α modulates the metabolic state of VSMCs by regulating the pathways that govern the switch between glycolysis and oxidative phosphorylation, thereby further advancing the calcification process.
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