A specific primer was designed using Primer Premier 5.0 software (Shanghai Shenggong Biology Engineering Technology Service, Shanghai, China) according to the nucleotide sequences of the human GSN gene, as reported in Genebank (www.ncbi.nlm.nih.gov/genbank/; reference sequence: NM_000177). The primer sequence for GSN was as follows: DCE-GSN-F: 5′-ATTCTAGAGCTAGCGAATTCATGGCTCCGCACCGCCCCG-3′; and DCE-GSN-R: 5′-CCTTCGCGGCCGCGGATCCTCAGGCAGCCAGCTCAGCC-3′. The coding DNA sequence region of the GSN gene was amplified in a thermal cycler (Gene Amp PCR system 2400, Perkin-Elmer, Foster City, CA, USA) according to the manufacturer's instructions. The target DNA gene fragment was subcloned into the DCE lentiviral vector to construct a GSN overexpression lentiviral vector (lenti-GSN).