Can 18F-alfatide micro-PET predict the radiotherapy response in Lewis lung carcinoma tumor-bearing C57BL/6 mice?

Abstract

e23011 Background: Integrin αvβ3 plays a major role in angiogenesis, tumor growth and progression. A new tracer, 18F-AL-NOTA-PRGD2, denoted as 18F-Alfatide, has been developed for positron emission tomography (PET) imaging of integrin αvβ3. This study aimed to explore the predictive role of integrin αvβ3 imaging with 18F-Alfatide PET in non-small cell lung cancer (NSCLC) for radiation and also to assess changes in tumor uptake during the course of radiotherapy. Methods: A total of 40 mice with lewis lung carcinoma (LLC) xenografts were divided into 4 groups (Ⅰ, Ⅱ, Ⅲ and Ⅳ) randomly. The Ⅰ underwent 18F-Alfatide Micro-PET scanning before and after radiotherapy, and so did the Ⅱ except for radiotherapy. The xenografts of Ⅲ were removed at the time before radiotherapy, while the Ⅳ’s were removed after radiotherapy. Tumor and muscle uptakes before and after radiotherapy of Ⅰ(SUVrad-1, SUVrad-2, SUVM-1, SUVM-2) and Ⅱ(SUVblank-1, SUVblank-2, SUVm-1, SUVm-2) depict 18F-Alfatide Micro-PET uptake. The expression of integrin αvβ3 in Ⅲ and Ⅳ xenografts was analyzed by western blotting. Results: The changes of ΔSUV1 ( SUVrad-2/SUVM-2―SUVrad-1/SUVM-1) was significantly lower than ΔSUV2 (SUVblank-2/ SUVm-2―SUVblank-1/ SUVm-1 ) (2.65±1.72 versus 5.16±2.50, P = 0.019. Overall survival (OS) of Ⅰ(56.70±25.34 day) is significantly longer than Ⅱ(35.00±5.27 day), P = 0.002. Significant negative correlation was found between ΔSUV and OS (R = 0.640, P = 0.002). Significant higher αvβ3 was observed in Ⅲ(0.52±0.09) than Ⅳ(0.41±0.07), P = 0.007. Conclusions: Decrease of ΔSUV and integrin αvβ3 during the course of radiotherapy may predict improved response in LLC xenografts and affirm the predictive role of 18F-Alfatide for radiation in NSCLC.