RT Journal Article
SR Electronic
T1 Tumor Microenvironment–Dependent <sup>18</sup>F-FDG, <sup>18</sup>F-Fluorothymidine, and <sup>18</sup>F-Misonidazole Uptake: A Pilot Study in Mouse Models of Human Non–Small Cell Lung Cancer
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP 1262
OP 1268
DO 10.2967/jnumed.111.098087
VO 53
IS 8
A1 Tao Huang
A1 A. Cahid Civelek
A1 Junling Li
A1 Huijie Jiang
A1 Chin K. Ng
A1 Gregory C. Postel
A1 Baozhong Shen
A1 Xiao-Feng Li
YR 2012
UL http://jnm.snmjournals.org/content/53/8/1262.abstract
AB 18F-FDG, 18F-fluorothymidine, and 18F-misonidazole PET scans have emerged as important clinical tools in the management of cancer; however, none of them have demonstrated conclusive superiority. The aim of this study was to compare the intratumoral accumulation of 18F-FDG, 18F-fluorothymidine, and 18F-misonidazole and relate this to specific components of the tumor microenvironment in mouse models of human non–small cell lung cancer (NSCLC). Methods: We used NSCLC A549 and HTB177 cells to generate subcutaneous and peritoneal xenografts in nude mice. Animals were coinjected with a PET radiotracer, pimonidazole (hypoxia marker), and bromodeoxyuridine (proliferation marker) intravenously 1 h before animal euthanasia. Tumor perfusion was assessed by Hoechst 33342 injection, given 1 min before sacrifice. The intratumoral distribution of PET radiotracers was visualized by digital autoradiography and related to microscopic visualization of proliferation, hypoxia, perfusion, stroma, and necrosis. Results: NSCLC xenografts had complex structures with intermingled regions of viable cancer cells, stroma, and necrosis. Cancer cells were either well oxygenated (staining negatively for pimonidazole) and highly proliferative (staining positively for bromodeoxyuridine) or hypoxic (pimonidazole-positive) and noncycling (little bromodeoxyuridine). Hypoxic cancer cells with a low proliferation rate had high18F-FDG and 18F-misonidazole uptake but low 18F-fluorothymidine accumulation. Well-oxygenated cancer cells with a high proliferation rate accumulated a high level of 18F-fluorothymidine but low 18F-FDG and18F-misonidazole. Tumor stroma and necrotic zones were always associated with low 18F-FDG, 18F-misonidazole, and 18F-fluorothymidine activity. Conclusion: In NSCLC A549 and HTB177 subcutaneously or intraperitoneally growing xenografts, 18F-fluorothymidine accumulates in well-oxygenated and proliferative cancer cells, whereas 18F-misonidazole and 18F-FDG accumulate mostly in poorly proliferative and hypoxic cancer cells. 18F-FDG and 18F-misonidazole display similar intratumoral distribution patterns, and both mutually exclude 18F-fluorothymidine.