Antitumor Effects of Interferon-Alpha on Cell Growth and Metastasis in Human Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma (NPC) is a highly malignant and frequently metastasized tumor, and the prognosis is very poor when distant metastases occur. Recently, immunotherapy is becoming a promising therapeutic approach. Interferon-alpha (IFN-alpha) represents the cytokines exhibiting the longest record of use in clinical oncology. In this study, we examined the antitumor effects of IFN-alpha 1b on NPC. The results showed that recombinant human IFN-alpha 1b (hIFN-alpha 1b) suppressed cell growth, induced a G1-phase cell cycle arrest in vitro, increased the expression of p16 and pRb, and decreased the expression of CCND1 and CDK6. In vivo analyses showed that either recombinant adeno-associated virus (rAAV)-IFN-alpha 1b or hIFN-alpha 1b treatment inhibited tumor growth and metastasis, reduced intratumoral microvessel density, increased cell apoptosis and necrosis, and induced prolonged survival. Notably, rAAV-IFN-alpha 1b or hIFN-alpha 1b treatment led to significantly higher serum levels of IL-12 and GM-CSF in mice compared to respective controls. Our findings suggest that IFN-alpha 1b acts as a multifunctional antitumor agent in NPC, which may have important therapeutic implications.