linderalactone and Glioblastoma

Glioblastoma multiforme (GBM) is a lethal and highly vascular type of brain tumor. We previously reported that isolinderalactone enhances GBM apoptosis in vitro and in vivo, but its role in tumor angiogenesis is unknown. Here, we investigated the anti-angiogenic activity of isolinderalactone and its mechanisms. In a human GBM xenograft mouse model, isolinderalactone significantly reduced tumor growth and vessels. Isolinderalactone decreased the expression of vascular endothelial growth factor (VEGF) mRNA, protein, and VEGF secretion in hypoxic U-87 GBM cells and also in xenograft GMB tissue. In addition, we demonstrated that isolinderalactone significantly inhibited the proliferation, migration, and capillary-like tube formation of human brain microvascular endothelial cells (HBMECs) in the presence of VEGF. We also found that isolinderalactone decreased sprout diameter and length in a 3D microfluidic chip, and strongly reduced VEGF-triggered angiogenesis in vivo Matrigel plug assay. Isolinderalactone downregulated hypoxia-inducible factor-1α (HIF-1α) and HIF-2α proteins, decreased luciferase activity driven by the VEGF promoter in U-87 cells under hypoxic conditions, and suppressed VEGF-driven phosphorylation of VEGFR2 in HBMECs. Taken together, our results suggest that isolinderalactone is a promising candidate for GBM treatment through tumor angiogenesis inhibition.

Topics: Angiogenesis Inhibitors; Animals; Basic Helix-Loop-Helix Transcription Factors; Brain Neoplasms; Cell Hypoxia; Cell Line, Tumor; Cell Proliferation; Cell Survival; Down-Regulation; Endothelial Cells; Gene Expression Regulation, Neoplastic; Glioblastoma; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Lab-On-A-Chip Devices; Male; Mice; Sesquiterpenes; Signal Transduction; Vascular Endothelial Growth Factor A; Xenograft Model Antitumor Assays

Glioblastoma multiforme (GBM) is the most common malignant brain tumor, which remains incurable. Plant extracts are a potential source of potent anticancer medicines. In this study, we investigated the effect of isolinderalactone from Lindera aggregata on tumor growth using U-87 human glioblastoma cells. Treatment with isolinderalactone inhibited cell viability and promoted apoptotic cell death. In addition, intraperitoneal injection of isolinderalactone significantly inhibited tumor growth in a human GBM xenograft mouse model. To identify the proteins involved in the induction of apoptosis in isolinderalactone-treated cells, we performed a human apoptosis proteome array analysis and western blotting. Isolinderalactone suppressed the expression of B-cell lymphoma 2 (BCL-2), as well as of survivin and X-linked inhibitor of apoptosis protein (XIAP), known as apoptosis inhibitors, and increased the level of cleaved caspase-3. In addition, isolinderalactone treatment increased cleaved poly(ADP-ribose) polymerase (PARP) and DNA damage. In xenograft tumor tissues, we observed high immunofluorescence of cleaved caspase-3 and TUNEL in isolinderalactone-treated group. Taken together, isolinderalactone enhances U-87 GBM cell apoptosis in vitro and in vivo and retards tumor growth, suggesting that isolinderalactone may be a potential candidate for anti-glioblastoma drug development.

Topics: Animals; Antineoplastic Agents, Phytogenic; Brain Neoplasms; Caspase 3; Cell Line, Tumor; Cell Survival; Gene Expression Regulation, Neoplastic; Glioblastoma; Humans; Injections, Intraperitoneal; Lindera; Mice; Poly(ADP-ribose) Polymerases; Proteomics; Proto-Oncogene Proteins c-bcl-2; Sesquiterpenes; Signal Transduction; Xenograft Model Antitumor Assays