The Nanoparticulate Quillaja Saponin BBE Is Selectively Active Towards Renal Cell Carcinoma

Aim: To characterize the cytotoxic effect of BBE, the particulate of desacyl-saponin, in model systems of solid tumours. Materials and Methods: Cytotoxic activity of BBE was investigated in solid human tumour cell lines, in tumour cells from patients with renal cell carcinoma, in normal human renal cells and in peripheral blood mononuclear cells. The BBE mode of cell death was assessed in vitro. In vivo effect of BBE was evaluated in xenograft-bearing mice. Results: BBE was selectively active against renal cell carcinoma, with no or little effect on normal cells. BBE induced caspase activity and apoptosis. An inhibitory activity of BBE on xenograft tumour growth, with no apparent signs of haematological toxicity was shown. In the non-proliferative model of patient tumour cells, BBE was active on only 1/5 patient samples, suggesting association of BBE effect with cell proliferation. Conclusion: BBE has interesting activities against renal cell carcinoma and should be further explored as a drug against this resistant tumour type.