Activity of Sulfonium Bisphosphonates on Tumor Cell Lines
journal contributionposted on 29.11.2007, 00:00 authored by Yonghui Zhang, Michael P. Hudock, Kilannin Krysiak, Rong Cao, Kyle Bergan, Fenglin Yin, Annette Leon, Eric Oldfield
We investigated three series of sulfonium bisphosphonates for their activity in inhibiting the growth of three human tumor cell lines. The first series consisted of 6 cyclic sulfonium bisphosphonates, the most active species having an (average) IC50 of 89 μM. The second consisted of 10 phenylalkyl and phenylalkoxy bisphosphonates, the most active species having an IC50 of 18 μM. The third series consisted of 17 n-alkyl sulfonium bisphosphonates, the most active species having an IC50 of ∼240 nM. Three QSAR models showed that the experimental cell growth inhibition results could be well predicted. We also determined the structures of one sulfonium bisphosphonate bound to farnesyl diphosphate synthase, finding that it binds exclusively to the dimethylallyl diphosphate binding site. These results are of interest since they show that sulfonium bisphosphonates can have potent activity against a variety of tumor cell lines, the most active species having IC50 values much lower than conventional nitrogen-containing bisphosphonates.