NSC56612, chloroquine, and hydroxychloroquine inhibit CXCL12-mediated activity.

<p>(A) Concentration dependent inhibition of fluorescently labeled CXCL12 (60 nM) binding to SNAP-tagged CXCR4 receptor in HEK293 cells by NSC56612, chloroquine, and hydroxychloroquine. The half maximal effective concentrations (EC₅₀), the values at which maximum CXCL12-CXCR4 binding is inhibited by 50%, for AMD3100, NSC56612, chloroquine, and hydroxychloroquine are 60.0 nM, 5.5 µM, 6.1 µM, and 9.8 µM, respectively. These curves are representative data from 3 experiments performed in duplicate. (B) Dose-dependent inhibition of CXCL12-induced β-arrestin-2-mediated beta-lactamase activity in engineered Tango assay by pretreatment with AMD 3100, NSC56612, chloroquine, and hydroxychloroquine. Emission data at 460/530 was defined as the response ratio. These curves are representative data from 3 experiments performed in duplicate. (C) Dose-dependent inhibition of CXCL12-induced intracellular calcium flux by AMD 3100, NSC56612, chloroquine, hydroxychloroquine. The CXCR4-mediated calcium influx was measured at 1 µM of AMD3100 and two different concentrations (100 µM and 200 µM) of the three compounds in Molt-4 cells. AMD 3100, NSC56612, chloroquine, and hydroxychloroquine showed 50 to 60% inhibition of CXCL12-induced calcium influx. These curves are representative data from 3 experiments performed in duplicate. (D) Inhibition of CXCL12-induced Jurkat cell migration in by AMD3100 (100 nM), NSC56612 (100 µM), chloroquine (100 µM), and hydroxychloroquine (100 µM). All four compounds showed 40% to 50% reduction in CXCL12-induced cell migration. The figure shows data from 4 experiments performed in duplicate. Error bars represent ± one SD. Student t-test: *<0.05 and **<0.01.