ABSTRACT
BACKGROUND: Clinical studies have shown that first-line use of anti-angiogenetic therapy can prolong progression-free survival but little progress has been made in extending the overall survival of the patients. We explored the role of ELK3 in glioma angiogenesis to improve and design more efficacious therapies. METHODS: A tissue microarray and immunohistochemistry analysis were used to determine the expression of ELK3 protein in 400 glioma patients. Cell proliferation, metastasis, cell cycle, and apoptosis were monitored in U87 and U251 cells using CCK-8, EdU, transwell assays, and flow cytometry. A tube-formation assay, a rat aorta ring sprouting assay, and a matrigel plug assay were performed to examine the antiangiogenic activity of ELK3. An ELISA, Western blot, and correlation analysis of the CGGA dataset were used to detect the association between ELK3 and VEGF-A or ELK3 and HIF-1[Formula: see text]. Besides, orthotopic transplantation in nude mice and histopathological and immunological analysis of in vitro tumors were used to explore the effect of ELK3 on tumor progression and median survival. RESULTS: ELK3 was upregulated in glioma tissues and associated with a poor prognosis. In vitro, ELK3 promoted cell proliferation and cell cycle progression, induced metastasis, and suppressed apoptosis. Then, silencing ELK3 inhibited VEGF-A expression and secretion by facilitating HIF-1[Formula: see text] degradation via ubiquitination. Finally, knockdown ELK3 inhibited tumor progression and angiogenesis in vitro and in vivo, as well as prolonged nude mice's median survival. CONCLUSIONS: Our findings first evidenced that ELK3 is crucial for glioma because it promotes angiogenesis by activating the HIF-1[Formula: see text]/VEGF-A signaling axis. Therefore, we suggest that ELK3 is a prognostic marker with a great potential for glioma angiogenesis and ELK3-targeted therapeutic strategies might hold promise in improving the efficacy of anti-angiogenic therapies.
Subject(s)
Glioma , Vascular Endothelial Growth Factor A , Animals , Mice , Mice, Nude , Vascular Endothelial Growth Factor A/metabolism , Glioma/pathology , Signal Transduction , Cell Proliferation , Hypoxia-Inducible Factor 1/metabolism , Cell Line, Tumor , Neovascularization, Pathologic/metabolismABSTRACT
BACKGROUND: Familial aggregation occurs in approximately 10% of cases of gastric cancer. The genetic predisposition or cause of the disease in only about 40% of hereditary gastric cancer cases is known, while the genetic factors of the remaining cases remain to be studied. METHODS: Samples were collected from a family with gastric cancer, including 3 gastric cancer and 17 healthy samples. Whole-exome sequencing was performed on samples from 3 patients with gastric cancer and 1 sample from healthy peripheral blood. SAMD9L was knocked down using small interfering RNAs and short hairpin RNA. The expression of SAMD9L was detected by quantitative real-time polymerase chain reaction and Western blot in SGC-7901 cells. CCK-8 assay was used to detect the proliferation of gastric cancer cells. The migration and invasion of gastric cancer cells were detected by Transwell assay and scratch assay. The cell apoptosis was detected by flow cytometry. RESULTS: Twelve single-nucleotide variants and 9 insertions/deletions mutation sites were identified as candidate genes. Among them, SAMD9L regulates cell proliferation as a tumor suppressor gene. The experiments of knocking down SAMD9L in SGC-7901 cells revealed that reduced expression of SAMD9L significantly enhanced the proliferation, migration, and invasion of SGC-7901 cells. CONCLUSIONS: These results suggest that SAMD9L inhibits the proliferation of gastric cancer cells, thereby increasing the risk of gastric cancer in people with SAMD9L downregulation. Therefore, SAMD9L may represent a susceptibility gene of this gastric cancer family.
