Epidermal growth factor (EGF) is a 53-amino acid cytokine (6.2 kDa) secreted by ectodermic cells, monocytes, kidneys and duodenal glands (1). EGF stimulates growth of epidermal and epithelial cells. EGF receptor (EGFR) is a transmembrane protein with an intracellular tyrosine kinase present on most cells. EGFR is overexpressed on many solid tumor cells, such as those of breast, non-small-cell lung, head and neck, and colon cancers (2-4). The high level of EGFR expression on cancer cells is associated with a poor prognosis (5-7). EGF has been labeled with 99mTc by various laboratories as a potential SPECT imaging agent for EGFR expression on cancer cells (8-11).
The Ras protein is a key regulator in the signaling pathway of the EGFR. Inhibition of farnesylation of Ras in cancer cells by farnesyltransferase inhibitors (FTI) led to inhibition of tumor growth, up regulation of EGFR, and decreased internalization of EGFR (12). 99mTc-HYNIC-EGF was developed for in vivo prediction of cancer cell response to FTI (8).
Hydrazinonicotinamide (HYNIC) was conjugated to human EGF to form HYNIC-EGF, which was purified by dialysis with a yield of >94% (8). A mixture of HYNIC-EGF and [99mTc]pertechnetate (74–370 MBq, 2–10 mCi) in reaction solution was incubated at room temperature for 20 min. 99mTc-HYNIC-EGF was purified by column chromatography to yield 81-95%, with a radiochemical purity of >95%. The specific activity of 99mTc-HYNIC-EGF was 1.23 Bq/nmol (33 pCi/nmol) for in vitro binding studies and 3.7–7.4 MBq/nmol (0.1–0.2 mCi/nmol) for the biodistribution studies.
In Vitro Studies: Testing in Cells and Tissues
99mTc-HYNIC-EGF was found to be stable in Ham’s F12 cell growth medium at 25ºC up to 4 h (8). LoVo human colon adenocarcinoma cells showed a Kd of 3.6 nM with 99mTc-HYNIC-EGF and 4.0 nM with [125I]EGF in saturation binding studies (8, 13). MAb88910 is a monoclonal antibody that inhibits EGF binding to EGFR. MAb88910 showed a Ki value of 1.7 nM and 1.3 nM for blocking 99mTc-HYNIC-EGF and [125I]EGF binding to LoVo cells, respectively (8, 13).
Normal mice were injected with injected i.v. with 99mTc-HYNIC-EGF (0.555 MBq, 0.015 mCi, 1 μg or 0.15 nmol) (8). The liver (55.0 ± 11.2% injected dose (ID)/g at 40 min) and kidneys (31.9 ± 18.4% ID/g at 5 min) were the major organs of uptake. A small amount was taken up by the small intestine (4.3 ± 1.8% ID/g at 2 h) and large intestine (7.7 ± 1.9% ID/g at 6 h) at later time points. Stomach activity was significantly higher than blood, beginning 20 min after injection. There was also some uptake in the spleen, which is maximal at 10 min after injection. After 48 h, only 52% of the injected 99mTc-HYNIC-EGF was excreted, whereas the remaining radioactivity was in the liver, kidneys, and spleen.
99mTc-HYNIC-hEGF was taken up in LoVo tumor tissue in tumor-bearing athymic mice (8). The tumor-to-thigh ratio was maximal at 2 h (2.5 ± 0.8). The nominal value of the uptake at 2 h was 3.5 ± 1.2%ID/g. Blocking with MAb88910 resulted in a decrease of the ratio from 2.5±0.8 to 1.2±0.2 (p<0.01). Co-injection of 100 μg of unlabelled EGF decreased the ratio to 1.1 ± 0.3 (p<0.01). In both cases, the muscle uptake did not change significantly. When comparing 99mTc-HYNIC-EGF tumor uptake data to 123I-EGF values, no significant differences were seen. Both tracers showed a maximum tumor-to-thigh ratio at 2 h (123I-EGF uptake ratio at 2 h was 2.0 ± 0.3). Pretreatment of tumor-bearing mice with FTI inhibitor (R115777, 100 mg/kg) for 6-8 h before 99mTc-HYNIC-EGF injection decreased the tumor-to-muscle ratio from 2.5 to 1.0. Similar results were also obtained using planar gamma scintigraphy imaging. The control experiment using 99mTc-HSA showed that the effect of FTI inhibition was not due to an influence on vascularization (13).
Other Non-Primate Mammals
No publication is currently available.
No publication is currently available
No publication is currently available.
- Carpenter G., Cohen S. Epidermal growth factor. J Biol Chem. 1990;265(14):7709–12. [PubMed: 2186024]
- Grunwald V., Hidalgo M. Developing inhibitors of the epidermal growth factor receptor for cancer treatment. J Natl Cancer Inst. 2003;95(12):851–67. [PubMed: 12813169]
- Mendelsohn J. Anti-epidermal growth factor receptor monoclonal antibodies as potential anti-cancer agents. J Steroid Biochem Mol Biol. 1990;37(6):889–92. [PubMed: 2285602]
- Yasui W., Sumiyoshi H., Hata J., Kameda T., Ochiai A., Ito H., Tahara E. Expression of epidermal growth factor receptor in human gastric and colonic carcinomas. Cancer Res. 1988;48(1):137–41. [PubMed: 2446740]
- Ang K.K., Berkey B.A., Tu X., Zhang H.Z., Katz R., Hammond E.H., Fu K.K., Milas L. Impact of epidermal growth factor receptor expression on survival and pattern of relapse in patients with advanced head and neck carcinoma. Cancer Res. 2002;62(24):7350–6. [PubMed: 12499279]
- Costa S., Stamm H., Almendral A., Ludwig H., Wyss R., Fabbro D., Ernst A., Takahashi A., Eppenberger U. Predictive value of EGF receptor in breast cancer. Lancet. 1988;2(8622):1258. [PubMed: 2903994]
- Ethier S.P. Growth factor synthesis and human breast cancer progression. J Natl Cancer Inst. 1995;87(13):964–73. [PubMed: 7629883]
- Cornelissen B., Kersemans V., Burvenich I., Oltenfreiter R., Vanderheyden J.L., Boerman O., Vandewiele C., Slegers G. Synthesis, biodistribution and effects of farnesyltransferase inhibitor therapy on tumour uptake in mice of 99mTc labelled epidermal growth factor. Nucl Med Commun. 2005;26(2):147–53. [PubMed: 15657509]
- Rusckowski M., Qu T., Chang F., Hnatowich D.J. Technetium-99m labeled epidermal growth factor-tumor imaging in mice. J Pept Res. 1997;50(5):393–401. [PubMed: 9401925]
- Yang W., Barth R.F., Leveille R., Adams D.M., Ciesielski M., Fenstermaker R.A., Capala J. Evaluation of systemically administered radiolabeled epidermal growth factor as a brain tumor targeting agent. J Neurooncol. 2001;55(1):19–28. [PubMed: 11804279]
- Capala J., Barth R.F., Bailey M.Q., Fenstermaker R.A., Marek M.J., Rhodes B.A. Radiolabeling of epidermal growth factor with 99mTc and in vivo localization following intracerebral injection into normal and glioma-bearing rats. Bioconjug Chem. 1997;8(3):289–95. [PubMed: 9177833]
- End D.W., Smets G., Todd A.V., Applegate T.L., Fuery C.J., Angibaud P., Venet M., Sanz G., Poignet H., Skrzat S., Devine A., Wouters W., Bowden C. Characterization of the antitumor effects of the selective farnesyl protein transferase inhibitor R115777 in vivo and in vitro. Cancer Res. 2001;61(1):131–7. [PubMed: 11196150]
- Cornelissen B., Thonissen T., Kersemans V., Van De Wiele C., Lahorte C., Dierckx R.A., Slegers G. Influence of farnesyl transferase inhibitor treatment on epidermal growth factor receptor status. Nucl Med Biol. 2004;31(6):679–89. [PubMed: 15246358]
Created: June 3, 2005; Last Update: January 11, 2012.
National Center for Biotechnology Information (US), Bethesda (MD)
Leung K. 99mTc-Hydrazinonicotinamide-epidermal growth factor. 2005 Jun 3 [Updated 2012 Jan 11]. In: Molecular Imaging and Contrast Agent Database (MICAD) [Internet]. Bethesda (MD): National Center for Biotechnology Information (US); 2004-2013.