Antitumor Activities and Apoptosis-regulated Mechanisms of Fermented Barley Extract in the Transplantation Tumor Model of Human HT-29 Cells in Nude Mice

Objective A subcutaneous transplantation tumor model of human HT-29 cells was established in nude mice to study the anticarcinogenic activities and apoptosis-regulatory mechanistic effect of aqueous extract of fermented barley with Lactobacillus plantarum dy-1 （LFBE）. Methods HT-29 cells were transplanted via subcutaneous injection of 1 × 107cells into the right flank of each nude mouse. Then, nude mice were treated for 30 days with LFBE （high-dose 2 g·kg-1·d-1; low-dose 1 g·kg-1·d-1） and for 7 days with 5-fluorouracil （5-FU, 25 g·kg-1·d-1） by gavage and intraperitoneal injection, respectively. Results Tumor volume and weight decreased significantly in both groups of nude mice treated with LFBE. In addition, the cell apoptosis rate of the LFBE group was significantly higher than that of the control group and 5-FU groups as measured by the TUNEL assay. Moreover, the real-time fluorescent quantitative PCR and Western blot methods further confirmed these apoptosis-enhancing and growth-inhibiting effects. The involvement of LFBE in inducing apoptosis was confirmed by the expression of Bax, Bcl-2, caspase-3, and cyclin D1. Conclusion The results showed that LFBE could induce subcutaneous transplantation tumor apoptosis in nude mice and could be used as a natural nutrient supplement or chemopreventive agent in the treatment of human colon cancer.