Molecular Imaging and Biology

, Volume 15, Issue 6, pp 748–757 | Cite as

In Vitro and In Vivo Evaluation of the Caspase-3 Substrate-Based Radiotracer [18F]-CP18 for PET Imaging of Apoptosis in Tumors

  • Chun-Fang Xia
  • Gang Chen
  • Umesh Gangadharmath
  • Luis F. Gomez
  • Qianwa Liang
  • Fanrong Mu
  • Vani P. Mocharla
  • Helen Su
  • A. Katrin Szardenings
  • Joseph C. Walsh
  • Tieming Zhao
  • Hartmuth C. KolbEmail author
Research Article



A novel caspase-3 substrate-based probe [18F]-CP18 was evaluated as an in vivo positron emission tomography (PET) imaging agent for monitoring apoptosis in tumors.


Uptake of [18F]-CP18 in cell assays and tumors was measured. Caspase-3/7 activities in cell lysates and tumor homogenates were determined. Autoradiography,Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), and cleaved caspase-3 immunostaining were performed on adjacent tumor sections to identify areas of apoptosis.


The in vitro cell assays showed caspase-3-dependent uptake of [18F]-CP18 in tumor cells when treated with an apoptosis inducer. The in vivo microPET imaging signal of [18F]-CP18 in xenograft tumors correlated with the ex vivo caspase-3/7 activities in these tumors. Furthermore, tumor autoradiographies of [18F]-CP18 in tumor sections matched adjacent sections stained by TUNEL and caspase-3 immunohistochemistry (IHC).


[18F]-CP18 demonstrated high affinity and selectivity for activated caspase-3 both in vitro and in vivo, and the results support [18F]-CP18 as a promising new PET imaging agent for apoptosis.

Key words

[18F]-CP18 Caspase-3 PET imaging Apoptosis Caspase imaging 


Conflict of Interest

The authors declare that they have no conflict of interest.


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Copyright information

© World Molecular Imaging Society 2013

Authors and Affiliations

  • Chun-Fang Xia
    • 1
  • Gang Chen
    • 1
  • Umesh Gangadharmath
    • 1
  • Luis F. Gomez
    • 1
  • Qianwa Liang
    • 1
  • Fanrong Mu
    • 1
  • Vani P. Mocharla
    • 1
  • Helen Su
    • 1
  • A. Katrin Szardenings
    • 1
  • Joseph C. Walsh
    • 1
  • Tieming Zhao
    • 1
  • Hartmuth C. Kolb
    • 1
    Email author
  1. 1.Molecular Imaging Biomarker ResearchSiemens Medical Solutions USA, Inc.Culver CityUSA

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