Discovery of Dimeric Arylsulfonamides as Potent ADAM8 Inhibitors

Abstract

The metalloproteinase ADAM8 is upregulated in several cancers but has a dispensable function under physiological conditions. In tumor cells, ADAM8 is involved in invasion, migration, and angiogenesis. The use of bivalent inhibitors could impair migration and invasion through the double binding to a homodimeric form of ADAM8 located on the cell surface of tumor cells. Herein we report the rational design and synthesis of the first dimeric ADAM8 inhibitors selective over ADAM10 and matrix metalloproteinases. Bivalent derivatives have been obtained by dimerizing the structure of a previously described ADAM17 inhibitor, JG26. In particular, derivative 2 was shown to inhibit ADAM8 proteolytic activity in vitro and in cell-based assays at nanomolar concentration. Moreover, it was more effective than the parent monomeric compound in blocking invasiveness in the breast cancer MDA-MB-231 cell line, thus supporting our hypothesis about the importance of inhibiting the active homodimer of ADAM8.

Figure 1

Chemical structure of JG26 and its dimeric derivatives 1–3. The spacer is depicted in red.

Figure 2

Binding interactions of JG26 with ADAM8 catalytic domain.

Figure 3

(A) Proposed trimeric adduct ADAM8–1–ADAM8. (B) H-bond network between the two ADAM8 monomers.

Scheme 1. Synthesis of Compounds 1 and 2

Reagents and conditions: (i) DIPEA, DMSO, rt, 24 h.

Scheme 2. Synthesis of Compound 3

Reagents and conditions: (i) N,N-DMF-di-tert-butyl acetal, toluene, 105 °C; (ii) TFA, DCM, 1 h, 0 °C; (iii) NaHCO₃, CHCl₃, rt; (iv) CDI, DCM, rt, 18 h; (v) TFA, DCM, 0 °C to rt; (vi) THP-ONH₂, HOBt, EDC, NMM, DMF, rt; (vii) TFA, DCM, rt.

Figure 4

Effects of new compounds 1–3 and JG26 (125 nM to 10 μM) on the shedding of CD23 in a cell-based assay using double-stable HEK cells (ADAM8/CD23). After the incubation of cells with 1–3 and JG26 for 24 h, cell supernatants were collected and subjected to an ELISA to determine the amount of soluble CD23. Data are the mean values from three independent experiments performed in triplicate. The following IC₅₀ values were calculated: Cpd 1: >1500 nM; Cpd 2: 350 nM; Cpd 3: 800 nM; JG26: 120 nM.

Figure 5

Effects of compounds 1–3 and JG26 on cancer cell invasion. MDA-MB-231 cells were pretreated with inhibitors for 24 h prior to the assay. Boxplot of invaded cells in %. Results are obtained from three independent experiments with counting of five randomly chosen viewing fields. One-way ANOVA was performed to determine statistical significance with * p < 0.05 and *** p < 0.001.