Nathália Kersting1, Bárbara Kunzler Souza1, Igor Araujo Vieira2, Rafael Pereira Dos Santos1,3, Danielly Brufatto Olguins1, Lauro José Gregianin4,5, André Tesainer Brunetto1,6, Algemir Lunardi Brunetto1,6, Rafael Roesler1,3, Caroline Brunetto de Farias1,6, Gilberto Schwartsmann1,7. 1. Cancer and Neurobiology Laboratory, Experimental Research Center, Clinical Hospital (CPE HCPA), Porto Alegre, Brazil. 2. Laboratory of Genomic Medicine, Experimental Research Center, Clinical Hospital (CPE-HCPA), Porto Alegre, Brazil. 3. Department of Pharmacology, Institute for Basic Health Sciences, Porto Alegre, Brazil. 4. Department of Pediatrics, Faculty of Medicine, Porto Alegre, Brazil. 5. Pediatric Oncology Service, Clinical Hospital, Federal University of Rio Grande do Sul, Porto Alegre, Brazil. 6. Rafael Koff Acordi Research Center, Children's Cancer Institute, Porto Alegre, Brazil. 7. Department of Internal Medicine, Faculty of Medicine, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
Abstract
OBJECTIVE: Ewing sarcoma (ES) is a type of childhood cancer probably arising from stem mesenchymal or neural crest cells. The epidermal growth factor receptor (EGFR) acts as a driver oncogene in many types of solid tumors. However, its involvement in ES remains poorly understood. METHODS: Human SK-ES-1 and RD-ES ES cells were treated with EGF, the EGFR inhibitor tyrphostin (AG1478), or phosphoinositide 3-kinase (PI3K) or extracellular-regulated kinase (ERK)/mitogen-activated kinase (MAPK) inhibitors. Cell proliferation survival, cycle, and senescence were analyzed. The protein content of possible targets of EGFR manipulation was measured by Western blot. RESULTS: Cell proliferation and survival were increased by EGF and inhibited by AG1478. The EGFR inhibitor also altered the cell cycle, inducing arrest in G1 and increasing the sub-G1 population, reduced polyploidy and increased the population of senescent cells. In addition, AG1478 reduced the levels of phosphorylated AKT (p-AKT), ERK, p-ERK, cyclin D1, and brain-derived neurotrophic factor (BDNF), while enhancing p53 levels. Cell proliferation was also impaired by inhibitors of PI3K or ERK, alone or combined with AG1478. CONCLUSIONS: Our findings reveal novel aspects of EGFR regulation of ES cells and provide early evidence for antitumor activities of EGFR inhibitors in ES.
OBJECTIVE:Ewing sarcoma (ES) is a type of childhood cancer probably arising from stem mesenchymal or neural crest cells. The epidermal growth factor receptor (EGFR) acts as a driver oncogene in many types of solid tumors. However, its involvement in ES remains poorly understood. METHODS:Human SK-ES-1 and RD-ES ES cells were treated with EGF, the EGFR inhibitor tyrphostin (AG1478), or phosphoinositide 3-kinase (PI3K) or extracellular-regulated kinase (ERK)/mitogen-activated kinase (MAPK) inhibitors. Cell proliferation survival, cycle, and senescence were analyzed. The protein content of possible targets of EGFR manipulation was measured by Western blot. RESULTS: Cell proliferation and survival were increased by EGF and inhibited by AG1478. The EGFR inhibitor also altered the cell cycle, inducing arrest in G1 and increasing the sub-G1 population, reduced polyploidy and increased the population of senescent cells. In addition, AG1478 reduced the levels of phosphorylated AKT (p-AKT), ERK, p-ERK, cyclin D1, and brain-derived neurotrophic factor (BDNF), while enhancing p53 levels. Cell proliferation was also impaired by inhibitors of PI3K or ERK, alone or combined with AG1478. CONCLUSIONS: Our findings reveal novel aspects of EGFR regulation of ES cells and provide early evidence for antitumor activities of EGFR inhibitors in ES.