Molecular and functional evaluation of a novel HIF inhibitor, benzopyranyl 1,2,3-triazole compound

Abstract

Hypoxia occurs in a variety of pathological events, including the formation of solid tumors. Hypoxia-inducible factor (HIF)-1α is stabilized under hypoxic conditions and is a key molecule in tumor growth and angiogenesis. Seeking to develop novel cancer therapeutics, we investigated small molecules from our in-house chemical libraries to target HIF-1α. We employed a dual-luciferase assay that uses a luciferase (Luc) reporter vector harboring five copies of hypoxia-responsive element (HRE) in the promoter. Under hypoxic conditions that increased Luc reporter activity by four-fold, we screened 144 different compounds, nine of which showed 30–50% inhibition of hypoxia-induced Luc reporter activity. Among these, “Compound 12, a benzopyranyl 1,2,3-triazole” was the most efficient at inhibiting the expression of HIF-1α under hypoxic conditions, reducing its expression by 80%. Under hypoxic conditions, the half maximal IC50 of the compound was 24 nM in HEK-293 human embryonic kidney cells, and 2 nM in A549 human lung carcinoma cells. Under hypoxic conditions, Compound 12 increased hydroxylated HIF-1α levels and HIF-1α ubiquitination, and also dose-dependently decreased HIF-1α target gene expression as well as vascular endothelial growth factor (VEGF) secretion. Furthermore, this compound inhibited VEGF-induced in vitro angiogenesis in human umbilical vein endothelial cells (HUVECs), and in vivo, it inhibited chick chorioallantoic membrane angiogenesis. In allogaft assays, cotreatment with Compound 12 and gefitinib significantly inhibited tumor growth and angiogenesis. Compound 12 can be a novel inhibitor of HIF-1α by accelerating its degradation, and shows much potential as an anti-cancer agent through its ability to suppress tumor growth and angiogenesis.

The transcriptional factors HIF-1 and HIF-2 and their novel inhibitors in cancer therapy

“…However, it decreases VEGF expression and angiogenesis in a dose-dependent manner. It has a synergistic effect with gefitinib, an Epidermal growth factor receptor (EGFR) inhibitor that is used clinically in lung and breast cancer with mutated and overactive EGFR, because the combination treatment inhibits tumor growth and angiogenesis in allograft model significantly 116 .…”

Ways into Understanding HIF Inhibition

“…In a similar mode of action the indole-3-ethylsulfamoylphenylacrylamide compound MPT0G157 acts via inhibition of multiple histone deacetylases (1, 2, 3, and 6) and decreased HIF-1α protein in colorectal cancer [52]. Alternatively, HIF-1α protein is reduced by the use of diazepinquinazolin-amine derivate BIX01294 which increases PHD2 and pVHL expression [53] or the drug benzopyranyl 1,2,3-triazole inducing HIF-1α hydroxylation and ubiquitination, leading to increased protein degradation [54]. Finally, kresoxim-methyl analogues have been shown to promote proteasomal degradation of HIF-1α via increased oxygen tension in cancer cells [55].…”

“…In a similar mode of action the indole-3-ethylsulfamoylphenylacrylamide compound MPT0G157 acts via inhibition of multiple histone deacetylases (1, 2, 3, and 6) and decreased HIF-1α protein in colorectal cancer [52]. Alternatively, HIF-1α protein is reduced by the use of diazepinquinazolin-amine derivate BIX01294 which increases PHD2 and pVHL expression [53] or the drug benzopyranyl 1,2,3-triazole inducing HIF-1α hydroxylation and ubiquitination, leading to increased protein degradation [54]. Finally, kresoxim-methyl analogues A different approach is to address the accumulation of HIF-1α protein using nanoparticles such as CRLX-101 that suppress HIF-1α protein translation and stability [56] or the substance class of so-called glyceollins from the soybean which block HIF-1α translation via inhibition of the Pi3K/AKT/mTOR pathway and decrease HIF-1α stability by decreasing Hsp90 binding ( Figure 2) [57].…”

HIFα as a target for different oncoproteins during carcinogenesis

“…Поэтому создание ингибиторов функционирования HIFα может иметь важное клиническое значение. Создаются препараты, ингибирующие функционирование HIFα, и они позиционируются в качестве веществ, обладающих противоопухолевой активностью [80,81].…”