Objective: To investigate whether chemically synthesized double-stranded RNA (dsRNA) targeting epidermal growth factor receptor (EGFR) can induce gene silencing in non-small cell lung cancer (NSCLC) cells in vivo.
Methods: The NSCLC cell line SPC-A1 was transfected with EGFR sequence-specific dsRNA formulated with Lipofectamine 2000. SPC-A1 cells (1 x 10(7)/ml) in 200 microl were injected s.c. into the left flank area of the athymic nude mice to establish a tumor-bearing nude mouse model. To calculate the tumor growth inhibition rate by measuring the diameter and the weight of the tumor. Immunohistochemistry and Western blot were used to monitor the reduction of EGFR protein production. Real-time RT-PCR was used to detect the silencing of the EGFR mRNA level.
Results: The EGFR sequence specific dsRNA (dsRNA-EGFR) significantly inhibited the tumor growth in vivo. The tumor growth inhibition rate was 75.0%. The dsRNA-EGFR sequence specifically silenced EGFR with 53.6% of down-regulation of EGFR protein production and 32.3% of silencing of EGFR mRNA level.
Conclusion: dsRNA-EGFR show a blockbuster effect in down-regulation of EGFR mRNA level and protein production, and inhibition of tumor growth in vivo.