An imaging study using laminin peptide 99mTc-YIGSR in mice bearing Ehrlich ascites tumour.
BACKGROUND
The YIGSR is a pentapeptide, from the laminin-1 of the beta1 chain, which can mediate cell adhesion and bind the 67 kD laminin receptor. The purpose is to evaluate the usefulness of (99m)Tc-YIGSR, a novel tumour radiotracer, in the receptor imaging of Ehrlich ascites tumour.


METHODS
Using S-acetly-NH3-MAG3 as chelate, YIGSR, a pentapeptide from laminin, was tagged with (99m)Tc. (99m)Tc-YIGSR was detected in the tumour group bearing Ehrlich ascites tumour and blocked group. Tumour, normal, inflammatory and blocked groups were imaged.


RESULTS
Through reverse phase Sep-Pak C18 chromatogram, it was revealed that YIGSR could conjugate with S-acetly-NH3-MAG3, and be radiolabelled at room temperature and neutral pH with a radiolabelling yield of 62%, and of 4% without chelate. (99m)Tc-YIGSR was rapidly cleared from kidney, then liver. The imaging findings showed tumour tissue accumulated initial radioactivity at fifteen minutes after injection in the tumour group, and the uptake increased to peak at three hours with a tumour/muscle ratio (T/M) of 11.36, then cleared slowly to a T/M of 7.50 at eight hours. The tumour uptake of radiotracer in blocked group was significantly lower with T/M of 4.61 at three hours and 0.89 at eight hours. The T/M was only 3.72 at three hours and 1.29 at eight hours after injection in inflammatory group. Compared with inflammatory group and control obstructive group, the ratio of T/M in tumour group was significantly different (P < 0.001).


CONCLUSIONS
Using S-acetly-NH3-MAG3, we radiolabelled YIGSR with (99m)Tc. (99m)Tc-YIGSR possesses many merits of tumour imaging: rapid visualization, high sensitivity and specificity, and satisfactory target/nontarget ratio. Our data suggest (99m)Tc-YIGSR is a promising tumour radiotracer.
Hu
Jia
J
Department of Nuclear Medicine, Union Hospital, Huazhong University of Science and Technology, Wuhan 430022, China. zhoudai2004@hotmail.com
Zhang
Yong-xue
YX
Lan
Xiao-li
XL
Qin
Guang-ming
GM
Zhang
Jun
J
Hu
Zhi-hong
ZH
D000818:Animals; D002286:Carcinoma, Ehrlich Tumor / Q000000981:diagnostic imaging*; D005260:Female; D007797:Laminin; D051379:Mice; D009842:Oligopeptides / Q000493:pharmacokinetics; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D013667:Technetium; D017263:Technetium Tc 99m Mertiatide; D014018:Tissue Distribution
D007797:Laminin; D009842:Oligopeptides; D019275:Radiopharmaceuticals; C121346:laminin 1; C081571:tyrosyl-isoleucyl-glycyl-seryl-arginine; D017263:Technetium Tc 99m Mertiatide; D013667:Technetium