Molecular Probes for Imaging the Sigma-2 Receptor: In Vitro and In Vivo Imaging Studies.
The sigma-2 (σ2) receptor has been validated as a biomarker of the proliferative status of solid tumors. Therefore, radiotracers having a high affinity and high selectivity for σ2receptors have the potential to assess the proliferative status of human tumors using noninvasive imaging techniques such as Positron Emission Tomography (PET). Since the σ2receptor has not been cloned, the current knowledge of this receptor has relied on receptor binding studies with the radiolabeled probes and investigation of the effects of the σ2receptor ligands on tumor cells. The development of the σ2selective fluorescent probes has proven to be useful for studying subcellular localization and biological functions of the σ2receptor, for revealing pharmacological properties of the σ2receptor ligands, and for imaging cell proliferation. Preliminary clinical imaging studies with [18F]ISO-1, a σ2receptor probe, have shown promising results in cancer patients. However, the full utility of imaging the σ2receptor status of solid tumors in the diagnosis and prediction of cancer therapeutic response will rely on elucidation of the functional role of this protein in normal and tumor cell biology.
Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
Chenbo
C
Zeng
Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
Elizabeth S
ES
McDonald
Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA. rmach@mail.med.upenn.edu.
Robert H
RH
Mach
D000818:Animals; D014408:Biomarkers, Tumor / Q000378:metabolism*; D049109:Cell Proliferation; D005456:Fluorescent Dyes / Q000737:chemistry*; D006801:Humans; D008024:Ligands; D018613:Microscopy, Confocal / Q000379:methods*; D057054:Molecular Imaging / Q000379:methods*; D009369:Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology; D049268:Positron-Emission Tomography / Q000379:methods*; D011237:Predictive Value of Tests; D019275:Radiopharmaceuticals / Q000737:chemistry*; D017480:Receptors, sigma / Q000378:metabolism*
D014408:Biomarkers, Tumor; D005456:Fluorescent Dyes; D008024:Ligands; D019275:Radiopharmaceuticals; D017480:Receptors, sigma; C106107:sigma-2 receptor
Breast cancer; Cell proliferation; Confocal microscopy; Positron emission tomography; Sigma-2 receptor