Background: The human Src homology 3 (SH3) domain GRB2-like 2 (SH3GL2) gene, a novel tumor suppressor gene in laryngeal squamous cell carcinoma (LSCC), induces apoptosis of tumor cells by regulating intra-cellular signal transduction networks. The objective of this study was to investigate the molecular mechanism of SH3GL2 in laryngeal carcinogenesis.
Material/Methods: RNA interference inhibited the expression of level of SH3GL, and RT-PCR and Western blotting were applied to evaluate the expression level of SH3GL2 after RNA interference. After RNA interference, flow cytometry and 3-(4,5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2H-tetrazolium bromide (MTT) assay were used to detect the biological effects, and Western blotting was used to determine the expression of EGFR and phosphorylated ERK1/2. The Hep2 cells transfected with siRNA-SH3GL2 were treated by U0126 (selective MEK1/2 Inhibitor), and the phosphorylated ERK1/2 proteins were detected by Western blotting; cell proliferation and apoptosis were detected subsequently.
Results: Our results show that the expression level of epidermal growth factor receptor (EGFR) and phosphorylated extracellular signal-regulated kinase1/2 (ERK1/2) were up-regulated after down-regulation of SH3GL2. Additionally, SH3GL2 promoted apoptosis while decreasing cell proliferation. However, if ERK1/2 was inhibited by U0126, the apoptosis rate increased and proliferation decreased inversely.
Conclusions: SH3GL2 participates in the regulation of apoptosis through the MEK-ERK signal pathway by adjusting EGFR in the laryngeal carcinoma cell line Hep2.

Keywords: Phosphorylation, RNA, Small Interfering - metabolism, Models, Biological, Mitogen-Activated Protein Kinase Kinases - metabolism, Mitogen-Activated Protein Kinase 3 - metabolism, Laryngeal Neoplasms - diagnosis, DNA Primers - genetics, Adaptor Proteins, Signal Transducing - physiology, Receptor, Epidermal Growth Factor - metabolism, Reverse Transcriptase Polymerase Chain Reaction