Abstract: Abstract: Objective To discuss the effect of knockdown of glucagon gene on insulinoma formation by using cells in vitro and animal model of insulinoma. Methods The expressions of insulin and glucagon proteins in INS-1 cells were observed by immunofluorescence staining and laser scanning confocal microscopy. Then INS-1 cells were infected with lentivirus pLVTHM-glucagon to knock down the glucagon gene. Therefore, an INS-1 cell line with low glucagon expression was established. Cells were divided into blank control group, lentivirus transfection group and glucagon knockdown group. The cell proliferation was detected by MTT assay. The ability to release insulin and glucagon was detected using ELISA and radioimmunity. And in vivo tumorigenicity of INS-1 cells was evaluated after glucagon gene knockdown. Expression levels of insulin and glucagon of tumor tissue were further detected by immunohistochemistry staining. Results Knockdown of glucagon gene impaired proliferation of INS-1 cells. The release of glucagon, but not insulin was decreased after glucagon knockdown. Subrenal capsul assay showed significantly reduced speed of neoplasia of INS-1 cells, with markedly decreased glucagon gene expression in this insulinoma tissue, which was displayed by immunohistochemical staining. Conclusion The knockdown of glucagon gene can inhibit proliferation of insulinoma cells, and release of glucagon, further restrain insulinoma formation. The result indicates that glucagon gene expression may be an important factor of the insulinoma formation.

Key words: insulinoma, insulin, glucose, glucagon, INS-1