Design, synthesis and validation of integrin alpha2beta1-targeted probe for microPET imaging of prostate cancer.

摘要

PURPOSE: The ability of PET to aid in the diagnosis and management of recurrent and/or disseminated metastatic prostate cancer may be enhanced by the development of novel prognostic imaging probes. Accumulating experimental evidence indicates that overexpression of integrin alpha(2)beta(1) may correlate with progression in human prostate cancer. In this study, (64)Cu-labeled integrin alpha(2)beta(1)-targeted PET probes were designed and evaluated for the imaging of prostate cancer. METHODS: DGEA peptides conjugated with a bifunctional chelator (BFC) were developed to image integrin alpha(2)beta(1) expression with PET in a subcutaneous PC-3 xenograft model. The microPET images were reconstructed by a two-dimensional ordered subsets expectation maximum algorithm. The average radioactivity accumulation within a tumor or an organ was quantified from the multiple region of interest volumes. RESULTS: The PET tracer demonstrated prominent tumor uptake in the PC-3 xenograft (integrin alpha(2)beta(1)-positive). The receptor specificity was confirmed in a blocking experiment. Moreover, the low tracer uptake in a CWR-22 tumor model (negative control) further confirmed the receptor specificity. CONCLUSION: The sarcophagine-conjugated DGEA peptide allows noninvasive imaging of tumor-associated alpha(2)beta(1) expression, which may be a useful PET probe for evaluating the metastatic potential of prostate cancer.