Prevention of tumor growth by needle-free jet injection of anti-C7orf24 siRNA.

Chromosome 7 open reading frame 24 (C7orf24), which was identified by proteome analysis, is upregulated in various types of cancer and is associated with cellular proliferation. However, in vivo antitumor effect by knockdown of C7orf24 has not been clarified. In this study, we investigated that the antitumor effect of anti-C7orf24 small interfering RNA (siRNA) administered by needle-free jet injection (JI) on lung cancer-bearing mice. Transfection of anti-C7orf24 siRNA induced cytotoxicity in cultured human lung cancer cells through specific knockdown of C7orf24. Furthermore, JI could effectively deliver anti-C7orf24 siRNA to tumor tissues, and as a result tumor growth was significantly inhibited. Immunohistochemical analysis revealed that C7orf24 levels were significantly reduced within tumor tissues collected from anti-C7orf24 siRNA-administered mice, indicating that the knockdown of C7orf24 induced cytotoxicity in tumor tissue. In conclusion, these data show for the first time that knockdown of C7orf24 prevents tumor growth in vivo following JI-mediated the siRNA delivery.