HRE-Luc Reporter Cell Line-HeLa

The growth of solid tumors is inevitably accompanied by hypoxia and angiogenesis. Understanding the true status of tissue hypoxia and angiogenesis during tumor progression will help further understand the tumor microenvironment and cancer treatment. Here, researchers used a hypoxia response element (HRE)-driven luciferase (LUC) reporter transfected cervical cancer cell line for hypoxia visualization. The hypoxia response activity of HRE-driven LUC was verified in HeLa cells and then monitored by bioluminescence imaging (BLI) through the HeLa-HRE-LUC tumor-bearing mouse model. An oxygen-sensitive nanoparticle was constructed for Ir(piq)3/IR780-loaded glycerol monooleate cubic liquid crystal material for phosphorescence-fluorescence imaging. Imaging results showed that the nanoparticles marking the hypoxic area overlapped with the BLI signal area detected by HRE-driven LUC in vivo, confirming that the hypoxia visualization platform can truly reflect the hypoxia level in vivo. The changes in deoxygenated/oxygenated hemoglobin detected by photoacoustic imaging reflect angiogenesis in vivo. Furthermore, the anticancer drug apigenin downregulated HIF-1α and VEGF under hypoxic conditions and inhibited tubule formation in vitro. The inhibitory effect was then validated in an in vivo hypoxia and angiogenesis visualization model.

Figure 1. Hypoxia-induced LUC expression in HeLa cells and establishment of a subcutaneous xenograft cervical tumor model in nude mice. (A) Construction of the recombinant lentiviral plasmid HRE-hCMVmp-LUC. (B) Relative activity ratio of HRE-LUC/RLUC in transient transfection experiments of HeLa cells treated with normoxia or hypoxia. (C) Relative activity ratio of HRE-LUC/RLUC in HeLa-HRE-LUC stable transfected cells treated with normoxia or hypoxia. (D) BLI of HeLa-HRE-LUC stable transfected cells after 24 h of hypoxia. (E) The semi-quantification of the cell bioluminescence intensity of (D). (F) BLI of the cancer model mouse inoculated with 10³, 10⁴, 10⁵ and 10⁶ HeLa-HRE-LUC cells. The area circled in red is the tumor. (G-H) The semi-quantification of the tumor bioluminescence intensity of (F) and (I). (I) BLI of the cancer model mice recorded at 1, 3, 8, 12, and 15 days. (Chen D, et al., 2023)