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2010 (9 / Total 43 )
- 1Liu S, Liu Z, Chen K, Yan Y, Watzlowik P, Wester HJ, Chin FT, Chen X. 18F-labeled galacto and PEGylated RGD dimers for PET imaging of alphavbeta3 integrin expression. Mol Imaging Biol. 2010;12:530-538.
Abstract
PURPOSE:
In vivo imaging of α(v)β(3) has important diagnostic and therapeutic applications. (18)F-Galacto-arginine-glycine-aspartic acid (RGD) has been developed for positron emission tomography (PET) imaging of integrin α(v)β(3) expression and is now being tested on humans. Dimerization and multimerization of cyclic RGD peptides have been reported to improve the integrin α(v)β(3)-binding affinity due to the polyvalency effect. Here, we compared a number of new dimeric RGD peptide tracers with the clinically used (18)F-galacto-RGD. PROCEDURES:
RGD monomers and dimers were coupled with galacto or PEG(3) linkers, and labeled with (18)F using 4-nitrophenyl 2-(18)F-fluoropropionate ((18)F-NFP) or N-succinimidyl 4-(18)F-fluorobenzoate as a prosthetic group. The newly developed tracers were evaluated by cell-based receptor-binding assay, biodistribution, and small-animal PET studies in a subcutaneous U87MG glioblastoma xenograft model. RESULTS:
Starting with (18)F-F(-), the total reaction time for (18)F-FP-SRGD2 and (18)F-FP-PRGD2 is about 120 min. The decay-corrected radiochemical yields for (18)F-FP-SRGD2 and (18)F-FP-PRGD2 are 52 ± 9% and 80 ± 7% calculated from (18)F-NFP. Noninvasive small-animal PET and direct tissue sampling experiments demonstrated that the dimeric RGD peptides had significantly higher tumor uptake as compared to (18)F-galacto-RGD. CONCLUSION:
Dimeric RGD peptide tracers with relatively high tumor integrin-specific accumulation and favorable in vivo kinetics may have the potential to be translated into clinic for integrin α(v)β(3) imaging. - 2Liu Z, Liu S, Niu G, Wang F, Liu S, Chen X. Optical Imaging of Integrin αvβ3 Expression with Near-Infrared Fluorescent RGD Dimer with Tetra(ethylene glycol) Linkers. Mol Imaging. 2010, 9(1):21-29.
Abstract
Integrin alphavbeta3 plays great roles in tumor angiogenesis, invasion, and metastasis. We report here the noninvasive visualization of tumor integrin alphavbeta3 expression by using near-infrared fluorescence (NIRF) imaging of an IRDye800-labeled new cyclic RGD (arginine-glycine-aspartic acid)dimer with tetra(ethylene glycol) (PEG4) linkers (ie, E[PEG4-c(RGDfK)]2, PEG4 = 15-amino-4,7,10,13-tetraoxapentadecanoic acid) in a U87MG tumor model. Fluorescent dye-labeled E[PEG4-c(RGDfK)]2 were subjected to in vitro cell staining, in vivo NIRF imaging, ex vivo NIRF imaging, and histologic studies. The in vitro and in vivo characterization of dye-labeled E[PEG4-c(RGDfK)]2 were compared with dye-labeled RGD dimer without PEG4 linkers (namely, E[c(RGDfK)]2). Both Cy5.5-E[PEG4-c(RGDfK)]2 and Cy5.5-E[c(RGDfK)]2 exhibited integrin alphavbeta3 binding specificity in a cell-staining experiment. In vivo NIRF imaging showed higher tumor accumulation and tumor to background contrast of IRDye800-E[PEG4-c(RGDfK)]2 over IRDye800-E[c(RGDfK)]2. The tumor integrin alphavbeta3 specificity of IRDye800-E[PEG4-c(RGDfK)]2 was confirmed by successful inhibition of tumor uptake in the presence of an excess dose of c(RGDfK). Histologic examination revealed both tumor vasculature and tumor cellintegrin alphavbeta3 binding of IRDye800-E[PEG4-c(RGDfK)]2 in vivo. In summary, NIRF imaging with IRDye800-E[PEG4-c(RGDfK)]2 offers an easy, fast, and low-cost way to detect and semiquantify tumor integrin alphavbeta3 expression in living subjects.http://dx.doi.org/10.2310/7290.2009.00032 - 3Liu Z, Jin C, Yu Z, Zhang J, Liu Y, Zhao H, Jia B*, Wang F*. Radioimmunotherapy of Human Colon Cancer Xenografts with 131I-Labeled Anti-CEA Monoclonal Antibody. Bioconjugate Chem. 2010, 21(2):314-318.
Abstract
Radioimmunotherapy (RIT) is a promising approach for the treatment of a wide variety of malignancies. The aim of this study was to investigate the therapeutic efficacy of (131)I-labeled anticarcinoembryonic antigen (CEA) monoclonal antibody CL58 in a human colon cancer mouse model. In vitro and in vivo characteristics of (125)I-CL58 were evaluated in LS180 human colon cancer cells and the nude mouse model. (131)I-CL58 was prepared and its in vivo therapeutic efficacy was tested. (125)I-CL58 showed high affinity to LS180 cells, as well as high tumor uptake and long tumor retention in LS180 tumor xenografts. (131)I-CL58 exhibited dose-dependent inhibition of LS180 tumor growth. With the excellent in vitro and in vivo characteristics, and the effective therapy for colon cancer in animal model, (131)I-CL58 is a promising agent for RIT of CEA-positive tumors including colon cancer. - 4Shi J, Liu Z, Jia B, Yu Z, Zhao H, Wang F* . Potential Therapeutic Radiotracers: Preparation, Biodistribution and Metabolic Characteristics of 177Lu-labeled cyclic RGDfK Dimer. Amino Acids. 2010, 39(1):111-120.
Abstract
In this study, we reported the preparation and evaluation of (177)Lu-DOTA-RGD2, (177)Lu-DOTA-Bz-RGD2 and (177)Lu-DTPA-Bz-RGD2 (RGD2 = E[c(RGDfK)](2)) as a potential therapeutic radiotracers for the treatment of integrin alpha(v)beta(3)-positive tumors. The BALB/c nude mice bearing the U87MG human glioma xenografts were used to evaluate the biodistribution characteristics and excretion kinetics of (177)Lu-DOTA-RGD2, (177)Lu-DOTA-Bz-RGD2 and (177)Lu-DTPA-Bz-RGD2. It was found that there were no major differences in their lipophilicity and biodistribution characteristics, particularly at latter time points. A major advantage of using DTPA-Bz as the bifunctional chelator (BFC) was its high radiolabeling efficiency (fast and high yield radiolabeling) at room temperature. Using DOTA and DOTA-Bz as BFCs, the radiolabeling kinetics was slow, and heating at 100 degrees C and higher DOTA-conjugate concentration were needed for successful (177)Lu-labeling. Therefore, DTPA-Bz is an optimal BFC for routine preparationof (177)Lu-labeled cyclic RGDfK peptides, and (177)Lu-DTPA-Bz-RGD2 is worthy of further investigation for targeted radiotherapy of integrin alpha(v)beta(3)-positive tumors. - 5Liu Z, Jia B*, Shi J, Jin X, Zhao H, Li F, Liu S, Wang F*. Tumor Uptake of the RGD Dimeric Probe 99mTc-G3-2P4-RGD2 is Correlated with Integrin αvβ3 Expressed on both Tumor Cells and Neovasculature. Bioconjugate Chem. 2010, 21(3):548–555.
Integrin αvβ3 has been well-documented as one of the key players in the process of tumor angiogenesis. Radiolabeled RGD (Arg-Gly-Asp) peptides that specifically target integrin αvβ3have great potential for tumor early detection and noninvasively monitoring the status of tumor angiogenesis. We developed a cyclic RGD dimeric probe 99mTc-HYNIC-Gly3-E[PEG4-c(RGDfK)]2 (99mTc-G3-2P4-RGD2) (using tricine and TPPTS as the coligands, TPPTS = trisodium triphenylphosphine-3,3′,3′′-trisulfonate), and investigated whether it could be used to noninvasively visualize and quantify integrin αvβ3 expression in vivo. HYNIC-Gly3-E[PEG4-c(RGDfK)]2 was synthesized and labeled with 99mTc. The biodistribution and planar γ-imaging studies of 99mTc-G3-2P4-RGD2 were performed in both U87MG (human integrin αvβ3positive/murine integrin αvβ3 positive) and HT-29 (human integrin αvβ3 negligible /murine integrin αvβ3 positive) tumor-bearing nude mouse models. The correlation of 99mTc-G3-2P4-RGD2 tumor uptake values (measured by ex vivo biodistribution) with expression levels of human integrin αvβ3 or murine integrin αvβ3 (measured by Western blot) were determined in U87MG and HT-29 tumor models, respectively. 99mTc-G3-2P4-RGD2 exhibited increased receptor binding affinity and in vivo tumor uptake as compared with previously reported RGD dimeric tracer 99mTc-RGD2 (without Gly3 and PEG4 spacers). The tumor uptake of 99mTc-G3-2P4-RGD2 was related to the expression levels of both human integrin αvβ3 (expressed on tumor cells) and murine integrin αvβ3 (expressed on newborn tumor vasculature). Our results demonstrate that 99mTc-G3-2P4-RGD2 is a useful agent for integrin αvβ3 imaging. The relationship between 99mTc-G3-2P4-RGD2 uptake and integrin αvβ3 expression level as determined by this study would provide useful information for clinical translation of RGD probes.
- 6Chakraborty S, Shi J, Kim YS, Zhou Y, Jia B, Wang F, Liu S. Evaluation of 111In-labeled Cyclic RGD Peptides: Tetrameric not Tetravalent. Bioconjugate Chem. 2010, 21(5):969-978.
Abstract
This report presents the synthesis and evaluation of (111)In(DOTA-6G-RGD(4)) (DOTA = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetracetic acid; 6G-RGD(4) = E{G(3)-E[G(3)-c(RGDfK)](2)}(2) and G(3) = Gly-Gly-Gly), (111)In(DOTA-RGD(4)) (RGD(4) = E{E[c(RGDfK)](2)}(2)) and (111)In(DOTA-3G-RGD(2)) (3G-RGD(2) = G(3)-E[G(3)-c(RGDfK)](2)) as new radiotracers for imaging integrin alpha(v)beta(3)-positive tumors. The IC(50) values of DOTA-6G-RGD(4), DOTA-RGD(4), and DOTA-3G-RGD(2) were determined to be 0.4 +/- 0.1, 1.4 +/- 0.1 and 1.1 +/- 0.1 nM against (125)I-c(RGDyK) bound to integrin alpha(v)beta(3)-positive U87MG human glioma cells. (111)In(DOTA-6G-RGD(4)), (111)In(DOTA-RGD(4)), and (111)In(DOTA-3G-RGD(2)) were prepared by reacting (111)InCl(3) with the respective DOTA conjugate in NH(4)OAc buffer (100 mM, pH = 5.5). Radiolabeling could be completed by heating the reaction mixture at 100 degrees C for 15-20 min. The specific activity was approximately 1850 MBq/micromol for (111)In(DOTA-3G-RGD(2)) and approximately 1480 MBq/micromol for (111)In(DOTA-6G-RGD(4)). The athymic nude mice bearing U87MG human glioma xenografts were used to evaluate tumor uptake and excretion kinetics of (111)In(DOTA-6G-RGD(4)), (111)In(DOTA-RGD(4)), and (111)In(DOTA-3G-RGD(2)). The results from both the integrin alpha(v)beta(3) binding assay and biodistribution studies suggest that the tetrameric cyclic RGD peptides, such as RGD(4) and 6G-RGD(4), are most likely bivalent in binding to the integrin alpha(v)beta(3). Both (111)In(DOTA-6G-RGD(4)) and (111)In(DOTA-RGD(4)) had significantly higher tumor uptake than (111)In(DOTA-3G-RGD(2)) at 24-72 h postinjection due to the extra RGD motifs in RGD(4) and 6G-RGD(4). (111)In(DOTA-3G-RGD(2)) had very little metabolism, while (111)In(DOTA-6G-RGD(4)) had significant metabolism during its excretion via both renal and hepatobiliary routes over the 2 h period, probably due to its much larger size. The combination of high tumor uptake with long tumor retention suggests that their corresponding (90)Y and (177)Lu analogues M(DOTA-6G-RGD(4)) (M = (90)Y and (177)Lu) might be useful as therapeutic radiotracers for treatment of integrin alpha(v)beta(3)-positive solid tumors. - 7Liu Z, Liu Y, Jia B, Zhao H, Jin X, Li F, Chen X, Wang F*. Epidermal Growth Factor Receptor–Targeted Radioimmunotherapy of Human Head and Neck Cancer Xenografts Using 90 Y-Labeled Fully Human Antibody Panitumumab. Mol Cancer Ther. 2010, 9(8):2297-2308.
Abstract
Panitumumab (ABX-EGF or Vectibix), the first fully human monoclonal antibody targeting epidermal growth factor receptor (EGFR), was approved by the Food and Drug Administration for treatment of patients with metastatic colorectal cancer. Here, we report for the first time the radioimmunotherapy(RIT) of EGFR-positive human head and neck cancer in a nude mouse model using pure beta(-) emitter (90)Y-labeled panitumumab. Biodistribution and planar gamma-imaging studies were carried out with (111)In-DOTA-panitumumab. The RIT efficacy of (90)Y-DOTA-panitumumab was evaluated in UM-SCC-22B tumor model. CD31, Ki67, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling, and H&E staining were done on UM-SCC-22B tumor sections after treatment. The tumor uptake of (111)In-DOTA-panitumumab in UM-SCC-22B tumor-bearing nude mice was 26.10 +/- 4.93, 59.11 +/- 7.22, 44.57 +/- 9.80, 40.38 +/- 7.76, and 14.86 +/- 7.23 % injected dose per gram of tissue at 4, 24, 72, 120, and 168 hours after injection, respectively. Immunotherapy with cold panitumumab (four doses of 10 mg/kg) did not cause significant antitumor effect. RIT with a single dose of 100 microCi (90)Y-DOTA-panitumumab caused significant tumor growth delay and improved the survival in UM-SCC-22B tumor model. A single dose of 200 microCi (90)Y-DOTA-panitumumab led to almost complete tumor regression (tumor volumes were 34.83 +/- 11.11 mm(3) and 56.02 +/- 39.95 mm(3) on days 0 and 46 after treatment, respectively). Histopathologic analysis of tumors and normal organs further validated the therapeutic efficacy and limited systemic toxicity of (90)Y-DOTA-panitumumab. The high tumor uptake and prolonged tumor retention, as well as effective therapy, reveal that (90)Y-DOTA-panitumumab may be a promising radioimmunotherapeutic agent to treat EGFR-positive solid tumors. (c) 2010 AACR.
- 8Liu Z*, Wang F*. Dual-targeted molecular probes for cancer imaging. Curr Pharm Biotech. 2010, 11(6):610-619.
Abstract
Molecular imaging provides a powerful tool for early disease detection, characterization, and real-time monitoring of therapeutic responses. Central to molecular imaging is the development of imaging probes. Receptors that are overexpressed in tumors have been potential targets for cancer imaging using targeted molecular probes. Since many cancer types simultaneously overexpress several receptors, the design of dual receptor-targeted molecular imaging probes has recently been proposed. Peptide heterodimers, and microbubble-based dual-targeted probes have shown especially good performance for in vivo cancer imaging. The success of these molecular probes demonstrates that the dual-targeting strategy is generally a good approach for developing molecular probes. In this review, we will introduce the current state of development of dual-targeted molecular imaging probes and summarize the various dual-targeted molecular probes for in vivo cancer imaging. - 9Cai J, Liu Z, Wang F, Li F*. Phage Display Applications for Molecular Imaging. Curr Pharm Biotech. 2010, 11(6):603-609(7).
