Genetic aberrations of key signaling pathways in human osteosarcoma

Abstract

Objective To performed microarray-based comparative genomic hybridization (aCGH) detection and carried out pathway analysis to gain a systemic view on the pathway alterations of the genetically altered genes in human osteosarcoma. Methods aCGH experiments were carried on 10 fresh osteosarcoma samples to obtain recurrent copy number change pattern, then the samples were further subjected to the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis to identify the altered pathways in the osteosarcoma. To validate the aberrations of these key pathways, the alterations of VEGF pathway were selected to confirm by the methods of fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) in formalin-fixed and paraffin-embedded (FFPE) osteosarcoma archival tissues. Results The KEEG analysis of aCGH data identified 33 genetically altered pathways in osteosarcomas. Among them 20 pathways were identified genetic amplifications, such as VEGF and mTOR signaling pathways. Thirteen pathways were genetic deletions, such as Wnt and Hedgehog signaling pathways. The genetic aberrations of cell-cell-matrix pathway such as CAMs, Adherens junction and Tight junction pathways implied the genetically alterations of these pathways which are associated with the tumor invasion and metastasis. Validation the aberrations of VEGF pathway showed that VEGFA gene was significantly amplified. The positive protein expression of VEGFA had a significant association with microvessel density (MVD). Conclusion There are genetic aberrations which involved the component genes of VEGF, mTOR, CAMs, Adherens junction, Wnt, Hedgehog and other 26 signaling pathways. The alterations of these pathways which are significantly associated with tumor invasion, metastasis and progression suggest that the genetic aberrations of these key pathways might contribute to the tumorigenesis and progression in human osteosarcoma, and provide molecular genetic evidence for targeted therapy. Key words: Osteosarcoma; Signal transduction; Microarray analysis; Comparative genomic hybridization