Abstract: ObjectiveTo investigate the effects of dendritic cells (DCs) loading alphaGalactosylceramide (αGalCer) combined with tumor specific cytotoxic T lymphocytes (CTLs) on the growth of transplanted Heps hepatoma in mice. MethodsWe induced the augmentation of the DC cells and T lymphocyte derived from the mice bone marrow, and enabled them to be specific CTLs. DC cells loaded αGalCer in vitro. First we established a Heps liver cancer xenograft model, then divided the model mice into 4 groups by random number table method (n=9): control group (intravenous injection with physiological saline), CTL group, DC loading αGalcer group and DC loading αGalcer combined with CTLs group. After 2 weeks of intervention, we extracted the tumor tissue, weighed the tumor and calculated the inhibition rate of tumor. The expressions of Bax/Bcl2 cells in groups of transplanted tumor tissues were detected using immunohistochemistry and Western blotting. ResultsThe average tumor weight of CTL group, DC loading αGalCer group and combined treatment group were (1.07±0.15)g, (1.11±0.17)g, (0.79±0.14)g, respectively. All of them were lower than that of control group (1.69±0.23)g, with significant differences (t=14.176, P=0.023; t=12.351, P=0.034; t=18.672, P=0.000). The average tumor weight of combined treatment group was lower than those of the CTL group and DC loading αGalCer group, with significant differences (t=15.236, P=0.012; t=11.176, P=0.037). Compared to the CTL group (36.69%) and DC loading αGalCer group (34.32%), the combined treatment group had a higher tumor inhibition rate (53.25%; P=0.034, P=0.021). Immunohistochemical assay showed that the numbers of Baxpositive cells in CTL group, DC loading αGalCer group and combined treatment group were 35.83±0.75, 33.67±0.82, 41.17±1.17 respectively, and compared with the control group (21.67±2.16), the differences were statistically significant (t=-13.789, P=0.002; t=-15.116, P=0.001; t=-17.452, P=0.000). The numbers of Baxpositive cells in combined treatment group were different with CTL group and DC loading αGalCer group (t=-7.730, P=0.009; t=-5.872, P=0.011). The numbers of Bcl2positive cells in CTL group, DC loading αGalCer group and combined treatment group were 30.83±0.75, 31.67±1.03, 25.00±0.89, and compared with the control group (38.67±1.21), the differences were statistically significant (t=9.234, P=0.007; t=11.738, P=0.003; t=20.608, P=0.000). The numbers of Bcl2positive cells in combined treatment group were different with CTL group and DC loading αGalCer group (t=11.952, P=0.003; t=12.223, P=0.002). Western blotting test results showed that the expression levels of Bax in CTL group, DC loading αGalCer group and combined treatment group were 0.46±0.01, 0.42±0.03, 0.55±0.01, and compared with the control group (0.31±0.02), the differences were statistically significant (t=1.035, P=0.032; t=1.124, P=0.027; t=1.425, P=0.010). The expression level of Bax in combined treatment group was different with CTL group and DC loading αGalCer group (t=1.305, P=0.013; t=1.421, P=0.010). The positive expressions of Bcl2 in CTL group, DC loading αGalCer group and combined treatment group were 0.34±0.03, 0.33±0.02, 0.24±0.01, and compared with the control group (0.46±0.01), the differences were statistically significant (t=-1.123, P=0.025; t=-1.061, P=0.031; t=1.278, P=0.014); the positive expression level of Bcl2 in combined treatment group was different with CTL group and DC loading αGalCer group (t=1.160, P=0.021; t=1.219, P=0.015). ConclusionIt has synergistic killing effect on transplanted Heps hepatoma in mice using DC loading αGalCer combined with the tumor specific CTL.

Key words: Dendritic cells, T-lymphocytes, Liver neoplasms, Natural killer T cells, alpha-Galactosylceramide