Abstract:

Objective To investigate the feasibility of baculovirus in gene transfer and therapeutic vector for thyroid carcinoma. Methods Recombinant baculovirus carrying green fluorescent protein (GFP) (Bac-GFP) was constructed with baculovirus Bac-to-Bac expression system. Human follicular thyroid carcinoma cell line FTC-133 was infected with Bac-GFP at different multiplicity of infection (MOI), and infection efficiency and GFP expression intensity were identified by flow cytometry. FTC-133 cells were infected by Bac-GFP with MOI of 100, and the duration of GFP expression was observed by fluorescence microscopy. The infection efficiency of Bac-GFP and the GFP expression intensity in the presence of different concentrations of sodium butyrate were determined by flow cytometry. FTC-133 cell survival after infection by Bac-GFP with different MOI was detected by MTT assay. Results Baculovirus vector Bac-GFP was successfully constructed, and FTC-133 cells were infected. The infection efficiency increased with MOI, and reached as high as 71.3% at MOI of 100. Sodium butyrate increased both the infection efficiency and GFP expression intensity, while there was no significant difference in the infection efficiency between the presence and absence of sodium butyrate. Fluorescence microscopy revealed that the expression of GFP in FTC-133 cells infected by Bac-GFP lasted two weeks. MTT assay indicated that there was no significant difference in cell survival among FTC-133 cells infected by Bac-GFP with different MOI （P>0.05）. Conclusion Recombinant baculovirus Bac-GFP has a high infection efficiency in FTC-133 cells, and the expression of report gene lasts longer, with no obvious cytotoxicity, which makes it a favourable vector for gene therapy of thyroid carcinoma.

Key words: thyroid carcinoma, baculovirus, report gene, green fluorescent protein