New Imaging Kit for Assessment of Estrogen Receptors with Single Photon Emission Computed Tomography
Abstract
To evaluate the feasibility of using 99mTc-glutamate peptide-estradiol (GAP-EDL) in imaging estrogen receptor positive (ER +) diseases. Methods: 3-Aminoethyl estradiol (EDL) was conjugated glutamate peptide (GAP) to yield GAP-EDL. Cellular uptake studies of 99mTc-GAP-EDL were conducted in ER (+) cell lines (MCF7 13762 and T47D). To demonstrate whether GAP-EDL increases MAP kinase acbvafion Western blot analysis of GAP-EDL was performed in 13762 cells. Biodistribution was conducted in 13762 breast tumor-bearing rats at 0.5-4 hrs. Each rat was administered 99mTc-GAP-EDL (10 microCifrat 10 microgmlrat iv). Two animal models (Rats and rabbits) were created to ascertain whether cellular or tumor uptake by 99mTc-GAP-EDL was via an ER-mediated process In tumor model breast tumor-bearing rats were pretreated with diethyistilbestrol (DES n=3 10 mglkg iv) 1 hr prior to receiving 99mTc-GAP-EDL (300 microCilrat iv). In endometriosis model part of rabbit uterine tissue was dissected and grafted in the peritoneal wall. The rabbit was administered with 99mTc-GAP-EDL (1 mCifrabbit iv). Results: There was 10-40% decreased uptake in cells treated with DES or tamoxifen compared to untreated 99mTc-GAP-EDL. Western blot analysis showed an ERK112 phosphorylation process with GAP-EDL. Biodistribution studies showed that tumor uptake and tumor-to-muscle count density ratio in 99mTc-GAP-EDL groups were significantly higher than in 99mTc-GAP groups at 4 hrs. In O9mTc-GAP-EDL ROl analysis of images showed that tumor-to muscle ratios were decreased in blocking groups. In endometriosis model the grafted uterine tissue could be visualized by 99mTc-GAP-EDL. Conclusion: A new imaging kit for assessment of estrogen receptors with single photon emission computed tomography (SPECT) was developed. Cellular or tumor uptake of 99mTc-GAP- EDL was via an estrogen receptor-mediated process. 99mTc GAP-EDL is a useful ER (+) imaging agent.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 2006
- Accession Number
- ADA463447
Entities
People
- Ali Azhdarinia
- David J. Yang
- E. E. Kim
Organizations
- The University of Texas MD Anderson Cancer Center