ABSTRACT
PURPOSE: TIMP-2 has been studied as an attractive cancer therapeutic candidate, and a TIMP-2 fusion protein (HSA/TIMP-2) displayed effective anticancer activity, despite a lack of information about its pharmacokinetics (PK) and biodistribution. The purpose of this work was to assess the PK and biodistribution of HSA/TIMP-2 as well as to quantify accumulated HSA/TIMP-2 in tumors. METHODS: Cy5.5 near-infrared (NIR) fluorescence was conjugated to the HSA/TIMP-2 protein (Cy5.5-HSA/TIMP-2) for monitoring spatio-temporal changes in vivo. For PK and biodistribution analysis, 0.2 µg/g body weight of Cy5.5-HSA/TIMP-2 was injected into MAT-LyLu prostate tumor xenografts, which were then imaged using an IVIS-200 optical imaging system. To quantify the accumulated HSA/TIMP-2 in tumors, we introduced a standard curve with depth-corrected fluorescence measurement. RESULTS: In the vascular tube formation assay with human umbilical vein endothelial cells (HUVECs), Cy5.5-HSA/TIMP-2 showed an antiangiogenic effect. In prostate cancer xenografts, Cy5.5-HSA/TIMP-2 exhibited a prolongation of blood half-life to 19.6 h and relatively preferential distribution to the tumor. The amount of tumor-accumulated Cy5.5-HSA/TIMP-2 was calculated to be 4.5 ± 0.5 ng/g body weight at 2 days, representing 2.25 ± 0.25% of the initial dose. CONCLUSIONS: We evaluated the pharmacokinetic profile and biodistribution of HSA/TIMP-2 with favorable results, providing new information for more effective approaches to cancer therapeutics using HSA/TIMP-2. Additionally, real-time in vivo fluorescence imaging analysis using a depth-corrected standard curve may serve as a platform to quantify biodistributed drug in anticancer therapeutic studies.
Subject(s)
Angiogenesis Inhibitors/pharmacokinetics , Recombinant Fusion Proteins/pharmacokinetics , Serum Albumin/pharmacokinetics , Tissue Inhibitor of Metalloproteinase-2/pharmacokinetics , Angiogenesis Inhibitors/blood , Animals , Carbocyanines/chemistry , Carbocyanines/pharmacokinetics , Half-Life , Human Umbilical Vein Endothelial Cells/cytology , Human Umbilical Vein Endothelial Cells/drug effects , Humans , Male , Mice , Mice, Inbred BALB C , Mice, Nude , Neoplasm Transplantation/methods , Prostatic Neoplasms/blood , Prostatic Neoplasms/metabolism , Rats , Recombinant Fusion Proteins/blood , Serum Albumin, Human , Spectroscopy, Near-Infrared/methods , Tissue Distribution , Transplantation, Heterologous , Tumor Cells, CulturedABSTRACT
Matrix metalloproteinases (MMPs) are principal participants in tumor development. In addition to serve as a useful biochemical marker, MMP expression may also provide a target for the diagnostic in vivo imaging of tumors, using a radiolabeled inhibitor. This study investigates the use of membrane type 1 (MT1)-MMP as target for in vivo tumor diagnosis. Specific binding of the endogenous tissue inhibitor of metalloproteinase-2 (TIMP-2) to MT1-MMP has been previously described. In this study, biodistribution and imaging experiments were performed on MT1-MMP-overexpressing (S.1.5) and control (C.IV.3) tumor-inoculated mice using [(123)I]-recombinant human TIMP-2 (rhTIMP-2) as radioligand and [(123)I]-rhTIMP-1 as control. The expression profile was controlled in vitro and on tumor extracts. rhTIMP-2 as well as rhTIMP-1 were labeled using the Iodogen method and characterized. Biodistribution of [(123)I]-rhTIMP-2 showed a tumor uptake of 2.87% ± 1.58% ID/g at 3 hours postinjection in S.1.5. Tumor values of [(123)I]-rhTIMP-1 and [(123)I]-rhTIMP-2 evaluated in S.1.5 and C.IV.3, respectively, were significantly lower. Planar imaging revealed significant uptake of [(123)I]-rhTIMP-2 in S.1.5 compared with contralateral background areas. This could not be observed in C.IV.3 and with [(123)I]-rhTIMP-1 in S.1.5. All tumors were well established (200-800 mg). These results suggest that rhTIMP-2 holds potential for development of radiotracers for in vivo imaging in overexpressing MT1-MMP but not in similar tumors that do not express this protease.
