Radionuclide imaging of integrin αvβ3 in nude mice with laryngeal and nasopharyngeal squamouscell carcinoma

Abstract

Objective To study the reliability of99Tcm-poly-(ethyleneglycol)(PEG)4-E(PEG4-c(RGDfK) )2 (99Tcm-3P-RGD2) as a radiotracer for integrin αvβ3 expression in laryngeal and nasopharyngeal squamous cell carcinoma in nude mice.Methods Twelve nude mice bearing human HEP-2 laryngeal carcinoma xenograft (n =6) and human CNE-1 nasopharyngeal carcinoma xenograft (n =6) were used for 99Tcm-3P-RGD2 planar imaging,and T/NT ratios were obtained with ROI technique.Afterwards,the biodistribution of 99Tcm-3P-RGD2 was analyzed in tumor beating nude mice,and the radioactivity in tumor and other organs (％ ID/g) were calculated.The immunostaining was performed to examine integrin αvβ3 expression in tumor tissue and semi-quantitative analysis was done according to the Fromowitz method.The independent samples t-test and linear correlation analysis were also used.Results The T/NT ratios of HEP-2 and CNE-1 bearing nude mice were 2.08 ±0.04 and 1.54 ±0.10 at 2 h post-injection,respectively.The radioactivity was (4.56 ± 0.67) ％ ID/g in HEP-2 tumor and ( 1.69 ± 0.18) ％ ID/g in CNE-1 tumor at 2 h post-injection.The T/NT ratios of tumor to blood and tumor to muscle were 6.37 ± 0.68 and 4.44 ± 0.42 in HEP-2 bearing nude mice,and 2.49 ±0.09 and 1.86 ±0.07 in CNE-1 bearing nude mice,respectively.The Fromowitz scores were 4.97 ± 0.37 and 2.60 ± 0.36 in HEP-2 and CNE-1 tumors,respectively.The T/NT ratio,the amount of radioactivity in tumor at 2 h post-injection and the Fromowitz score of HEP-2 bearing nude mice were all significantly higher than those of CNE-1 bearing nude mice (t =11.83,7.17 and 11.31respectively,all P ＜ 0.05 ).The T/NT ratios at 2 h post-injection were correlated well with Fromowitz scores (HEP-2:r2h =0.97,P＜0.05; CNE-1:r'2h =0.97,P＜0.05).Conclusion 99Tcm-3P-RGD2 imaging could be a noninvasive and effective method for monitoring integrin αv β3 expression in laryngeal and nasopharyngeal squamous cell carcinoma. Key words: Laryngeal neoplasms; Nasopharyngeal neoplasms; Cell adhesion molecules; Radionuclide imaging; Mice, nude