A dual inhibitor of matrix metalloproteinases and a disintegrin and metalloproteinases, [18F]FB-ML5, as a molecular probe for non-invasive MMP/ADAM-targeted imaging
作者:Nathalie Matusiak、Riccardo Castelli、Adriaan W. Tuin、Herman S. Overkleeft、Rosalina Wisastra、Frank J. Dekker、Laurette M. Prély、Rainer P.H. Bischoff、Aren van Waarde、Rudi A.J.O. Dierckx、Philip H. Elsinga
DOI:10.1016/j.bmc.2014.11.013
日期:2015.1
Background: Numerous clinical studies have shown a correlation between increased matrix metalloproteinase (MMP)/a disintegrin and metalloproteinase (ADAM) activity and poor outcome of cancer. Various MMP inhibitors (MMPIs) have been developed for therapeutic purposes in oncology. In addition, molecular imaging of MMP/ADAM levels in vivo would allow the diagnosis of tumors. We selected the dual inhibitor of MMPs and ADAMs, ML5, which is a hydroxamate-based inhibitor with affinities for many MMPs and ADAMs. ML5 was radiolabelled with F-18 and the newly obtained radiolabelled inhibitor was evaluated in vitro and in vivo.Materials and methods: ML5 was radiolabelled by direct acylation with N-succinimidyl-4-[F-18]fluorobenzoate ([F-18]SFB) for PET (positron emission tomography). The resulting radiotracer [F-18]FB-ML5 was evaluated in vitro in human bronchial epithelium 16HBE cells and breast cancer MCF-7 cells. The non-radioactive probe FB-ML5 and native ML5 were tested in a fluorogenic inhibition assay against MMP-2, -9, -12 and ADAM-17. The in vivo kinetics of [F-18]FB-ML5 were examined in a HT1080 tumor-bearing mouse model. Specificity of probe binding was examined by co-injection of 0 or 2.5 mg/kg ML5. Results: ML5 and FB-ML5 showed high affinity for MMP-2, -9, -12 and ADAM-17; indeed IC50 values were respectively 7.4 +/- 2.0, 19.5 +/- 2.8, 2.0 +/- 0.2 and 5.7 +/- 2.2 nM and 12.5 +/- 3.1, 31.5 +/- 13.7, 138.0 +/- 10.9 and 24.7 +/- 2.8 nM. Radiochemical yield of HPLC-purified [F-18]FB-ML5 was 13-16% (corrected for decay). Cellular binding of [F-18]FB-ML5 was reduced by 36.6% and 27.5% in MCF-7 and 16HBE cells, respectively, after co-incubation with 10 mu M of ML5. In microPET scans, HT1080 tumors exhibited a low and homogeneous uptake of the tracer. Tumors of mice injected with [F-18]FB-ML5 showed a SUVmean of 0.145 +/- 0.064 (n = 6) which decreased to 0.041 +/- 0.027 (n = 6) after target blocking (p < 0.05). Ex vivo biodistribution showed a rapid excretion through the kidneys and the liver. Metabolite assays indicated that the parent tracer represented 23.2 +/- 7.3% (n = 2) of total radioactivity in plasma, at 90 min post injection (p.i.).Conclusion: The nanomolar affinity MMP/ADAM inhibitor ML5 was successfully labelled with F-18. [F-18]FB-ML5 demonstrated rather low binding in ADAM-17 overexpressing cell lines. [F-18]FB-ML5 uptake showed significant reduction in the HT1080 tumor in vivo after co-injection of ML5. [F-18]FB-ML5 may be suitable for the visualization/quantification of diseases overexpressing simultaneously MMPs and ADAMs. (C) 2014 Elsevier Ltd. All rights reserved.