Towards dual inhibitors of the MET kinase and WNT signaling pathway; design, synthesis and biological evaluation

Abstract

Both the kinase MET and the WNT signaling pathway are attractive targets in cancer therapy, and synergistic effects have previously been observed in animal models upon simultaneous inhibition. A strategy towards a designed multiple ligand of MET and WNT signaling is pursued based on the two hetero biaryl systems present in both the MET inhibitor tepotinib and WNT signaling inhibitor TC-E 5001. Initial screening was conducted to find the most suitable ring systems for further optimization, whereas a second screen explored modifications towards pyridazinones and triazolo pyridazines. Up to 54% reduction of WNT signaling activity at 10 μM concentration was achieved, however, only low affinities towards MET were observed. Overall, the thiophene substituted pyridazinone 40 was the best dual MET and WNT signaling inhibitor, with a 17% and 19% reduction of activity, respectively. Although further optimizations are needed to achieve more potent dual inhibitors, the strategy presented herein can be valuable towards the development of a dual inhibitor of MET and WNT signaling.

Fig. 1. Examples of inhibitors of TNKS1/2 and MET.

Fig. 2. Construction of the generalized target structure 9. (a) Similarities between TC-E 5001 (2) and tepotinib (8) are highlighted; (b) merging of pharmacophores yields the target structure 9; (c) the target structure can be synthesized via S_N2 reactions from commercial starting materials. See the experimental data for synthetic details.

Fig. 3. In silico docking of: (a) tepotinib (8) and TC-E 5001 (2) in MET; (b) tepotinib (8) and TC-E 5001 (2) in TNKS1.

Fig. 4. Molecules evaluated in the initial screen at 10 μM concentration, presented with values from MET and WNT signaling assays. Inhibition values are presented as averages from ≥2 parallels.

Scheme 1. Synthesis of pyridazinone and triazolo pyridazine analogs. (i) Boronic acid, Pd(dppf)Cl₂·CH₂Cl₂, K₂CO₃, 1,4-dioxane, H₂O, 80 °C, 15 h; (ii) hydrazine hydrate, EtOH, 80 °C, 3–5 h; (iii) CS₂, KOH, EtOH, rt for 48 h or 80 °C for 15 h; (iv) AcOH, 80 °C for 4 h or 100 °C for 15 h. Yields are given for isolated structures.

Fig. 5. Molecules evaluated in the second screen at 10 μM concentration, presented with values from MET and WNT signaling assays. Inhibition values are presented as averages from ≥2 parallels.