Abstract. The present study determined the ability of the Lactobacillus rhamnosus GG strain (LGG) to enhance the anticancer effects of geniposide on HSC-3 human oral squamous carcinoma cells.LGG (1.0x10 3 CFU/ml) on its own had no impact on human oral keratinocytes and HSC-3 cancer cells. Geniposide (25 or 50 µg/ml) had no impact on human oral keratinocytes, but exerted growth inhibitory effects on HSC-3 cancer cells, which were increased in the presence of LGG. Flow cytometric analysis and a nuclear staining assay with DAPI revealed that HSC-3 cancer cells treated with LGG-geniposide (1.0x10 3 CFU/ml LGG and 50 µg/ml geniposide) had a higher apoptotic rate than cells in other treatment groups, particularly that treated with geniposide (50 µg/ml) only. Geniposide also increased the mRNA and protein expression of caspase-3, -8 and -9 as well as B-cell lymphoma 2 (Bcl-2)-associated X protein, p53, p21, inhibitor of nuclear factor-κB (NF-κB) α, Fas and Fas ligand, while decreasing Bcl-2, Bcl extra large protein, inhibitor of apoptosis-1 and -2, NF-κB, cyclooxigenase-2 and inducible nitric oxide synthase in HSC-3 cells, which was increased in the presence of LGG. These results indicated that LGG enhanced the anticancer effects of geniposide in HSC-3 cells.
IntroductionGardenia jasminoides Ellis belongs to the Rubiaceae family and Gardenia genus, and its dried ripe fruit can be used as a medicine, with bitter and cold taste, and nourishing the heart, lungs and San Juao meridian according to the principles of Chinese Medicine (1). Gardenia fruit mainly protects the liver and nourishes the gallbladder, and its active constituent is geniposide, which belongs to the iridoid glycosides (2). It is also rich in other constituents such as organic acids, pigments and volatile oils (3). A pharmacokinetic study has found that geniposide, the active constituent of Gardenia jasminoides Ellis, is hydrolyzed by β-glucosidase produced by intestinal microorganisms to generate genipin (4). Studies have proved that genipin also significantly reduces inflammation, lipid peroxidation and angiogenesis, with low cytotoxicity, sound biocompatibility and high anti-degradation ability (5,6). Gardenia jasminoides Ellis has a low genipin content, which only accounts for 0.005-0.01%, and mainly exists in the form of its precursor-geniposide, accounting for 3-5%. At present, geniposide is extracted with organic solvents, and 100 g gardenia fruit provide ~4 g geniposide. Therefore, it is of great significance to ferment Gardenia by microorganisms to produce genipin (7). In addition, the use of microorganisms and geniposide may achieve a better control of the concentration of active constituents, which may enhance the pharmacological effect. The transformation of geniposide contained in Gardenia jasminoides by fermentation with microorganisms is carried out by β-glucosidase produced by bacteria, which breaks chemical bonds in geniposide to produce genipin (8).In the present study, high-yield lactobacillus produced by β-glucosidase was used to react...