Abstract

As a domestic anaerobic bacterium in the human body, Bifidobacterium longum can selectively germinate and proliferate in the hypoxic regions of solid tumors. Selenium (Se) has been found to inhibit carcinogenesis and tumor growth. In our previous study, we demonstrate that B. longum carrying pBV22210-Endostatin (B. longum-En) inhibit tumor growth. In this study, we enriched Se to B. longum-En (Se-B. longum-En) to evaluate the antitumor efficacy when delivered orally or intravenously on H22 tumor-bearing mice and examined the distribution of Se in vivo. The results showed that Se-B. longum-En could significantly inhibit tumor growth as well as extend the median survival time of tumor-bearing mice. The concentration-time curve suggested that Se could be absorbed and disseminated rapidly in vivo. The results also showed that there was a dose-effect relationship between Se and tumor inhibition rate and the antitumor effect was more pronounced when Se-B. longum-En was delivered via vein than by oral route. Based on the results, B. longum carrying endostatin gene and enriched with Se may be a potential agent in cancer gene therapy.

Key words: Bifidobacterium longum, endostatin, selenium, tumor, gene therapy.