Background: Viscum album agglutinin-1 (VAA-1) is assumed to be the biologically most active ingredient of misteltoe extracts that are often used as adjuvant cancer therapy. To develop new approaches for lung cancer treatment, we evaluated the antineoplastic activity of VAA-1 alone and in combination with other chemotherapeutic drugs, including doxorubicin, cisplatin and taxol in the human lung carcinoma cell line A549.
Materials and methods: Cytotoxicity was determined by 5-bromo-2'-deoxyuridine (BrdU) ELISA-assays and drug interaction assessed by the isobologram method. Analysis of cell cycle distribution was obtained using flow cytometry.
Results: For all drug combinations tested the outcome was additive with the combination of VAA-1 and cycloheximide showing strong synergistic effects. Moreover, VAA-1 induced G1-phase accumulation mechanisms without causing apoptosis.
Conclusion: Our findings suggest that the simultaneous administration of VAA-1 with all anticancer agents tested is advantageous since cytotoxic effects are enhanced. These data may provide new clinicalperspectives in future mistletoe therapy.