The Experimental Studies On ¹¹C-meisoindigo PET In Lung Cancer Diagnosis And Chemotherapeutic Effect Monitoring

Objective: 1. To investigate uptake of ¹¹C-meisoindigo by four kinds of lung cancer cells ( LA795, 95-C, 95-D and H460). 2. To investigate the biodistribution and positron emission tomography (PET) imaging of ¹¹C-meisoindigo in a murine model of LA795 lung carcinoma. 2. To study the biodistribution and PET imaging of ¹¹C-meisoindigo in a murine model of inflammation. 3. To evaluate the use of ¹¹C-meisoindigo as a new PET tracer for monitoring tumor response to chemotherapy.Methods: 1. Four kinds of lung cancer cells were divided into ¹¹C-meisoindigo and ¹⁸F-FDG groups, ¹¹C-meisoindigo or ¹⁸F-FDG was added into different lung cancer cells respectively. According to the different tracers and after adding time, cell uptake of ¹¹C-meisoindigo group examined at 5,15,20min with well-gammadetector, cell uptake of ¹⁸F-FDG groups examined at 30,60,90,120,150min. 2. 20 mice bearing LA795 lung adenocarcinoma were divided into four groups according to the different tracers and time after injection at random, A group(5min), B group(15min,) and C group(20min) after ¹¹C-meisoindigoinjection, D group( 60min ) after ¹¹F-FDG injection. The biodistribution of mice for ¹¹C-meisoindigo was measured with well-gamma detector at 5, 15 and 20min after ¹¹C-meisoindigo injection from tail veins. And the biodistribution of mice for F-FDG was examined at 60min after injection. In addition, the PET imaging of mice was performed using two tracers. 3. 10 the mice model with inflammation were divided into two groups according to the different tracers at random, ¹¹C-meisoindigo and ¹⁸F-FDG group. The biodistribution of mice for ¹¹C-meisoindigo and ¹⁸F-FDG was measured with well-gamma detector atl5, 60 min after injection, respectively. The PET imaging of mice was also performed using two tracers. 4. 30 mice bearing LA795 lung adenocarcinoma were divided into three groups according to days of chemotherapy at random, A group(untreated controls), B group(1 day) and C group(2 day )after chemotherapy. Each group was also divided into two groups according to two radioactive tracers, ¹¹C-meisoindigo and ¹⁸F-FDG groups. The mice of group B and group C were treated with cisplatin, then, injected with ¹¹C-meisoindigo or ¹⁸F-FDG. Tumor biodistribution of all mice was measured with well-gamma detector at 15, 60 min after injection and the PET imaging of mice was performed respectively. Tumor proliferation was determined by immunohistochemical examination of proliferating cell nuclear antigen (PCNA).Results: 1. ¹¹C-meisoindigo and ¹⁸F-FDG were all uptake by four kinds of lung cancer cells. uptake of ¹¹C-meisoindigo was more than ¹⁸F-FDG, time of maximum uptake of ¹¹C-meisoindigo was 15min after injection, uptake of ¹¹C-meisoindigo by H460 cell was more than others. Uptake of ¹⁸F-FDG by cells increased with time prolonged, The maximum increasing time of uptake was 90min, uptake of ¹⁸F-FDG by 95D cell was more than others. 2. In the biodistribution study of ¹¹C-meisoindigo, considerable radioactive uptake of tumor was observed, and much radioactivity was showed in liver and kidney. The ratios of tumor/blood, tumor/muscle and tumor/lung were all above 2.0. The tumor PET images with ¹¹C-meisoindigo were clear. 3. Uptake of ¹⁸F-FDG by inflammation tissues was higher than those of ¹¹C-meisoindigo. Inflammatory tissues were visible in ¹⁸F-FDG PET images, no visible in ¹¹C-meisoindigo PET. 4. Tumor ¹¹C-meisoindigo uptake decreased rapidly after treatment of cisplatin. ¹¹C-meisoindigo uptake in tumor was significantly was decreased more than that of ¹⁸F-FDG The PET imaging confirmed lower tumor ¹¹C-meisoindigo retention in group B and group C compared with group A. PCNA decreased after treatment of cisplatin in B and C groups than A group significantly.Conclusions: Lung cancer cells can uptake of ¹¹C-meisoindigo, and the uptake of ¹¹C-meisoindigo in lung cancer tissues is higher than that normal tissues, and inflammatory tissues are invisible in ¹¹C-meisoindigo PET images, so the lung cancer could be identified with ¹¹C-meisoindigo PET imaging. The decrease in tumor ¹¹C-meisoindigo uptake after chemotherapy was more than that of ¹⁸F-FDG Changes in ¹¹C-meisoindigo uptake could correspond changes of PCNA, ¹¹C-meisoindigo is a promising PET tracer for monitoring Chemotherapeutic effect of lung cancer. Our preliminary study of ¹¹C-meisoindigo in lung cancer showed it maybe a promising PET tracer in lung cancer diagnosis and chemotherapeutic effect monitoring...