Abstract
Purpose
To quantitatively evaluate the utility of a translocator protein (TSPO)-targeted near-infrared (NIR) probe (NIR-conPK11195) for in vivo molecular imaging of TSPO in breast cancer.
Procedures
NIR-conPK11195 uptake and TSPO-specificity were validated in TSPO-expressing human breast adenocarcinoma cells (MDA-MB-231). In vivo NIR-conPK11195 biodistribution and accumulation were quantitatively evaluated in athymic nude mice bearing MDA-MB-231 xenografts.
Results
Fluorescence micrographs illustrated intracellular labeling of MDA-MB-231 cells by NIR-conPK11195. Quantitative uptake and competition assays demonstrated dose-dependent (p < 0.001) and TSPO-specific (p < 0.001) NIR-conPK11195 uptake. In vivo, NIR-conPK11195 preferentially labeled MDA-MB-231 tumors with an 11-fold (p < 0.001) and 7-fold (p < 0.001) contrast enhancement over normal tissue and unconjugated NIR dye, respectively.
Conclusions
NIR-conPK11195 appears to be a promising TSPO-targeted molecular imaging agent for visualization and quantification of breast cancer cells in vivo. This research represents the first study to demonstrate the feasibility of TSPO imaging as an alternative breast cancer imaging approach.
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References
American Cancer Society (2009) Cancer Facts and Figures. Atlanta: American Cancer Society
Elmore JG, Armstrong K, Lehman CD, Fletcher SW (2005) Screening for breast cancer. JAMA 293(10):1245–1256
Carney PA, Miglioretti DL, Yankaskas BC et al (2003) Individual and combined effects of age, breast density, and hormone replacement therapy use on the accuracy of screening mammography. Ann Intern Med 138(3):168–175
DeMartini W, Lehman C, Partridge S (2008) Breast MRI for cancer detection and characterization: a review of evidence-based clinical applications. Acad Radiol 15(4):408–416
Stavros AT, Thickman D, Rapp CL, Dennis MA, Parker SH, Sisney GA (1995) Solid breast nodules: use of sonography to distinguish between benign and malignant lesions. Radiology 196(1):123–134
Bremer C, Ntziachristos V, Weissleder R (2003) Optical-based molecular imaging: contrast agents and potential medical applications. Eur Radiol 13(2):231–243
Cerussi A, Shah N, Hsiang D, Durkin A, Butler J, Tromberg BJ (2006) In vivo absorption, scattering, and physiologic properties of 58 malignant breast tumors determined by broadband diffuse optical spectroscopy. J Biomed Opt 11(4)
Godavarty A, Thompson AB, Roy R et al (2004) Diagnostic imaging of breast cancer using fluorescence-enhanced optical tomography: phantom studies. J Biomed Opt 9(3):488–496
Intes X (2005) Time-domain optical mammography SoftScan: Initial results. Acad Radiol 12(8):934–947
Ntziachristos V, Chance B (2001) Probing physiology and molecular function using optical imaging: applications to breast cancer. Breast Cancer Res 3(1):41–46
Ntziachristos V, Yodh AG, Schnall M, Chance B (2000) Concurrent MRI and diffuse optical tomography of breast after indocyanine green enhancement. Proc Natl Acad Sci U S A 97(6):2767–2772
Tromberg BJ, Cerussi A, Shah N et al (2005) Imaging in breast cancer—diffuse optics in breast cancer: detecting tumors in pre-menopausal women and monitoring neoadjuvant chemotherapy. Breast Cancer Res 7(6):279–285
Kaijzel EL, van der Pluijm G, Lowik CWGM (2007) Whole-body optical imaging in animal models to assess cancer development and progression. Clin Cancer Res 13(12):3490–3497
Luker GD, Luker KE (2008) Optical imaging: current applications and future directions. J Nucl Med 49(1):1–4
Margolis DJ, Hoffman JM, Herfkens RJ, Jeffrey RB, Quon A, Gambhir SS (2007) Molecular imaging techniques in body imaging. Radiology 245(2):333–356
Dose Schwarz J, Bader M, Jenicke L, Hemminger G, Janicke F, Avril N (2005) Early prediction of response to chemotherapy in metastatic breast cancer using sequential 18F-FDG PET. J Nucl Med 46(7):1144–1150
Schelling M, Avril N, Nahrig J et al (2000) Positron emission tomography using [(18)F]fluorodeoxyglucose for monitoring primary chemotherapy in breast cancer. J Clin Oncol 18(8):1689–1695
Smith IC, Welch AE, Hutcheon AW et al (2000) Positron emission tomography using [(18)F]-fluorodeoxy-d-glucose to predict the pathologic response of breast cancer to primary chemotherapy. J Clin Oncol 18(8):1676–1688
Wahl RL, Zasadny K, Helvie M, Hutchins GD, Weber B, Cody R (1993) Metabolic monitoring of breast cancer chemohormonotherapy using positron emission tomography: initial evaluation. J Clin Oncol 11(11):2101–2111
Been LB, Elsinga PH, de Vries J et al (2006) Positron emission tomography in patients with breast cancer using (18)F-3′-deoxy-3′-fluoro-l-thymidine ((18)F-FLT)-a pilot study. Eur J Surg Oncol 32(1):39-43
Kenny L, Coombes RC, Vigushin DM, Al-Nahhas A, Shousha S, Aboagye EO (2007) Imaging early changes in proliferation at 1 week post chemotherapy: a pilot study in breast cancer patients with 3′-deoxy-3′-[18F]fluorothymidine positron emission tomography. Eur J Nucl Med Mol Imaging 34(9):1339–1347
Pio BS, Park CK, Pietras R et al (2006) Usefulness of 3′-[F-18]fluoro-3′-deoxythymidine with positron emission tomography in predicting breast cancer response to therapy. Mol Imaging Biol 8(1):36–42
Smyczek-Gargya B, Fersis N, Dittmann H et al (2004) PET with [18F]fluorothymidine for imaging of primary breast cancer: a pilot study. Eur J Nucl Med Mol Imaging 31(5):720–724
Jonson SD, Welch MJ (1998) PET imaging of breast cancer with fluorine-18 radiolabeled estrogens and progestins. Q J Nucl Med 42(1):8–17
Linden HM, Stekhova SA, Link JM et al (2006) Quantitative fluoroestradiol positron emission tomography imaging predicts response to endocrine treatment in breast cancer. J Clin Oncol 24(18):2793–2799
Mankoff DA, Link JM, Linden HM, Sundararajan L, Krohn KA (2008) Tumor receptor imaging. J Nucl Med 49:149S–163S
Mankoff DA (2006) Radiotracer breast cancer imaging: beyond FDG and MIBI. Phys Med 21(Suppl 1):12–16
Pantaleo MA, Nannini M, Maleddu A et al (2008) Conventional and novel PET tracers for imaging in oncology in the era of molecular therapy. Cancer Treat Rev 34(2):103–121
Quon A, Gambhir SS (2005) FDG-PET and beyond: molecular breast cancer imaging. J Clin Oncol 23(8):1664–1673
Papadopoulos V, Baraldi M, Guilarte TR et al (2006) Translocator protein (18 kDa): new nomenclature for the peripheral-type benzodiazepine receptor based on its structure and molecular function. Trends Pharmacol Sci 27(8):402–409
Black KL, Ikezaki K, Toga AW (1989) Imaging of brain tumors using peripheral benzodiazepine receptor ligands. J Neurosurg 71(1):113–118
Han Z, Slack RS, Li W, Papadopoulos V (2003) Expression of Peripheral Benzodiazepine Receptor (PBR) in human tumors: relationship to breast, colorectal, and prostate tumor progression. J Recept Signal Transduct. 23(2–3):225–238
Hardwick M, Fertikh D, Culty M, Li H, Vidic B, Papadopoulos V (1999) Peripheral-type benzodiazepine receptor (PBR) in human breast cancer: correlation of breast cancer cell aggressive phenotype with PBR expression, nuclear localization, and PBR-mediated cell proliferation and nuclear transport of cholesterol. Cancer Res 59(4):831–842
Hardwick M, Rone J, Han Z, Haddad B, Papadopoulos V (2001) Peripheral-type benzodiazepine receptor levels correlate with the ability of human breast cancer MDA-MB-231 cell line to grow in SCID mice. Int J Cancer 94(3):322–327
Maaser K, Grabowski P, Sutter AP et al (2002) Overexpression of the peripheral benzodiazepine receptor is a relevant prognostic factor in stage III colorectal cancer. Clin Cancer Res 8(10):3205–3209
Starosta-Rubinstein S, Ciliax BJ, Penney JB, McKeever P, Young AB (1987) Imaging of a glioma using peripheral benzodiazepine receptor ligands. Proc Natl Acad Sci U S A 84(3):891–895
Venneti S, Lopresti BJ, Wiley CA (2006) The peripheral benzodiazepine receptor (Translocator protein 18 kDa) in microglia: from pathology to imaging. Prog Neurobiol 80(6):308–322
Deane NG, Manning HC, Foutch AC et al (2007) Targeted imaging of colonic tumors in smad3−/− mice discriminates cancer and inflammation. Mol Cancer Res 5(4):341–349
Manning HC, Goebel T, Marx JN, Bornhop DJ (2002) Facile, efficient conjugation of a trifunctional lanthanide chelate to a peripheral benzodiazepine receptor ligand. Org Lett 4(7):1075–1078
Ma G, Gallant P, McIntosh L (2007) Sensitivity characterization of a time-domain fluorescence imager: eXplore Optix. Appl Opt 46(10):1650–1657
Bai M, Wyatt SK, Han Z, Papadopoulos V, Bornhop DJ (2007) A novel conjugable translocator protein ligand labeled with a fluorescence dye for in vitro imaging. Bioconjug Chem 18(4):1118–1122
Kozikowski AP, Kotoula M, Ma D, Boujrad N, Tuckmantel W, Papadopoulos V (1997) Synthesis and biology of a 7-nitro-2,1,3-benzoxadiazol-4-yl derivative of 2-phenylindole-3-acetamide: a fluorescent probe for the peripheral-type benzodiazepine receptor. J Med Chem 40(16):2435–2439
Manning HC, Goebel T, Thompson RC, Price RR, Lee H, Bornhop DJ (2004) Targeted molecular imaging agents for cellular-scale bimodal imaging. Bioconjug Chem 15(6):1488–1495
Manning HC, Smith SM, Sexton M et al (2006) A peripheral benzodiazepine receptor targeted agent for in vitro imaging and screening. Bioconjug Chem 17(3):735–740
Taliani S, Simorini F, Sergianni V et al (2007) New fluorescent 2-phenylindolglyoxylamide derivatives as probes targeting the peripheral-type benzodiazepine receptor: design, synthesis, and biological evaluation. J Med Chem 50(2):404–407
Iyer AK, Khaled G, Fang J, Maeda H (2006) Exploiting the enhanced permeability and retention effect for tumor targeting. Drug Discov Today 11(17-18):812–818
Bai M, Rone MB, Papadopoulos V, Bornhop DJ (2007) A novel functional translocator protein ligand for cancer imaging. Bioconjug Chem 18(6):2018–2023
Benavides J, Quarteronet D, Imbault F et al (1983) Labelling of "peripheral-type" benzodiazepine binding sites in the rat brain by using [3H]PK 11195, an isoquinoline carboxamide derivative: kinetic studies and autoradiographic localization. J Neurochem 41(6):1744–1750
Chaki S, Funakoshi T, Yoshikawa R et al (1999) Binding characteristics of [3H]DAA1106, a novel and selective ligand for peripheral benzodiazepine receptors. Eur J Pharmacol 371(2–3):197–204
Ferzaz B, Brault E, Bourliaud G et al (2002) SSR180575 (7-chloro-N,N,5-trimethyl-4-oxo-3-phenyl-3,5-dihydro-4H-pyridazino[4,5-b]i ndole-1-acetamide), a peripheral benzodiazepine receptor ligand, promotes neuronal survival and repair. J Pharmacol Exp Ther 301(3):1067–1078
Newman AH, Lueddens HW, Skolnick P, Rice KC (1987) Novel irreversible ligands specific for "peripheral" type benzodiazepine receptors: (+/−)-, (+)-, and (−)-1-(2-chlorophenyl)-N-(1-methylpropyl)-N- (2-isothiocyanatoethyl)-3-isoquinolinecarboxamide and 1-(2-isothiocyanatoethyl)-7-chloro-1,3-dihydro-5-(4-chlorophenyl )-2H-1,4-benzodiazepin-2-one. J Med Chem 30(10):1901–1905
Okuyama S, Chaki S, Yoshikawa R et al (1999) Neuropharmacological profile of peripheral benzodiazepine receptor agonists, DAA1097 and DAA1106. Life Sci 64(16):1455–1464
Romeo E, Auta J, Kozikowski AP et al (1992) 2-Aryl-3-indoleacetamides (FGIN-1): a new class of potent and specific ligands for the mitochondrial DBI receptor (MDR). J Pharmacol Exp Ther 262(3):971–978
Vin V, Leducq N, Bono F, Herbert JM (2003) Binding characteristics of SSR180575, a potent and selective peripheral benzodiazepine ligand. Biochem Biophys Res Commun 310(3):785–790
Acknowledgements
The authors would like to acknowledge ART Advanced Research Technologies Inc. and the United States Army Department of Defense for financial support of this research as well as LI-COR Biosciences, Inc. for providing a portion of the dye used in this study. HCM acknowledges support from a Career Development Award from the NCI (K25 CA127349).
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Significance: This is the first study to demonstrate the feasibility of molecular imaging of the translocator protein (TSPO), previously termed the peripheral benzodiazepine receptor, as a potential approach to breast cancer imaging. The TSPO represents an attractive target for molecular imaging of disease due to its overexpression in a variety of neurological disorders and cancers, including breast cancer, as well as its correlation with disease stage and clinical prognosis.
We demonstrate that a near-infrared (NIR) TSPO-targeted probe developed in our laboratory (NIR-conPK11195) selectively labels in vivo breast cancer cells in a pre-clinical model of human breast adenocarcinoma (MDA-MB-231). NIR-conPK11195 exhibits significant dose-dependent cellular uptake and TSPO-specificity in in vitro MDA-MB-231 cells (p < 0.001). In vivo, NIR-conPK11195 preferential labels MDA-MB-231 tumors with an 11-fold contrast enhancement over normal tissue and a 7-fold improvement in fluorescence signal with respect to free (unconjugated) NIR dye (p < 0.001).
Given the importance of molecular imaging in cancer detection, diagnosis, and monitoring of disease as well as the impact of pre-clinical studies on therapeutic efficacy monitoring and drug discovery, we believe the utility of NIR-conPK11195 for molecular imaging of TSPO in breast cancer will be of considerable interest to both the molecular imaging and cancer research communities. Furthermore, this work represents a potentially translational methodology as radiolabeled PK 11195 has already been used in the clinic for imaging of neurodegenerative diseases and gliomas.
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Wyatt, S.K., Manning, H.C., Bai, M. et al. Molecular Imaging of the Translocator Protein (TSPO) in a Pre-Clinical Model of Breast Cancer. Mol Imaging Biol 12, 349–358 (2010). https://doi.org/10.1007/s11307-009-0270-8
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DOI: https://doi.org/10.1007/s11307-009-0270-8