The Synergistic Anti-Tumor Activity of Phenylacetate and Adherent LAK Cells from Patients with Hepatocellular Carcinoma

Objective: To improve the preparation of adherent lymphokine-activated killer cells (A-LAK cells) and to study the synergistic anti-tumor effect of phenylacetate(PA) and A-LAK cells. Methods: A-LAK cells were obtained from peripheral blood mononuclear cells (PBMC) of patients with hepatocellular carcinoma (HCC) by using L-phenylalanine methyl ester (PME) to deplete immunosuppressive monocytes. The proliferation of SMMC7721 cell line treated with PA was studied. A-LAK cells were treated with the supernatant derived from SMMC7721 cells treated with PA previously and the changes of proliferation and anti-tumor activity of A-LAK cells were observed. Results: The expansion of A-LAK cells was significantly higher than that of non-adherent LAK (NA-LAK) as well as standard LAK cells. The growth of SMMC7721 cells was significantly suppressed by PA. The supernatant of cultured tumor cells intensely suppressed the proliferation and cytotoxic activity of A-LAK cells, but the suppressive effect of supernatant treated with PA previously was decreased. Conclusion: A-LAK could be simply prepared by using PME, and have the synergistic anti-tumor effect with phenylacetate.