Jk. Chung et al., Mechanisms related to [F-18]fluorodeoxyglucose uptake of human colon cancers transplanted in nude mice, J NUCL MED, 40(2), 1999, pp. 339-346
Citations number
34
Categorie Soggetti
Radiology ,Nuclear Medicine & Imaging","Medical Research Diagnosis & Treatment
[F-18]Fluorodeoxyglucose ([F-18]FDG), a glucose analogue, has been widely u
sed for tumor imaging. To investigate the mechanisms related to [F-18]FDG u
ptake by tumors, an experiment involving nude mice was performed. Methods:
Human colon cancer cell lines SNU-C2A, SNU-C4 and SNU-C5 were transplanted
to nude mice. Using immunohistochemical staining and Western blot, the expr
ession of glucose transporter (Glut) isoforms (Glut-1 similar to 5) in xeno
grafted tumors was analyzed. For the analysis of messenger ribonucleic acid
(mRNA) expression, reverse-transcription polymerase chain reaction and Nor
thern blot were used and the enzyme activity of hexokinase in cancer tissue
s was measured by continuous spectrophotometric rate determination. Results
: [F-18]FDG uptake in SNU-C4 and SNU-C5 cells was higher than in normal col
on cells. Among these cells and xenografted tumors, SNU-C5 showed the highe
st level of [F-18]FDG uptake, followed by SNU-C4 and SNU-C2A. An immunostai
ning experiment showed intense staining of Glut-1 in SNU-C5 tumors but some
what faint staining in SNU-C4. SNU-C5 tumors also showed positive staining
with Glut-3, although this was not the case with SNU-C2A and SNU-C4. Wester
n blot analysis showed the expression of Glut-1 and Glut-3 in all tumors. E
xperiments involving Northern blot analysis and reverse-transcription polym
erase chain reaction confirmed the overexpression of Glut-1 mRNA in all tum
ors, with the highest level in SNU-C5. The level of Glut-3 mRNA was also el
evated in SNU-C5 tumors but not in SNU-C2A and SNU-C4. The enzyme activity
of hexokinase did not vary among different tumors. Conclusion: Gluts, espec
ially Glut-1, are responsible for [F-18]FDG uptake in a nude mouse model of
colon cancer rather than hexokinase activity. Increased numbers of glucose
transporters at the plasma membrane of cancer cells is attributed to an in
creased level of transcripts of glucose transporter genes and may be a caus
e of increased [F-18]FDG uptake, at least in colon cancer tumors.