A preliminary study of imaging paclitaxel-induced tumor apoptosis with (99)Tc(m)-His10-Annexin V / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>In tumors the process of apoptosis occurs over an interval of time after chemotherapy. It is important to determine the best time for detecting apoptosis by in vivo imaging. In this study, we evaluated the dynamics and feasibility of imaging non-small cell lung cancer (NSCLC) apoptosis induced by paclitaxel treatment using a (99)Tc(m)-labeled Annexin V recombinant with ten consecutive histidines (His10-Annexin V) in a mouse model.</p><p><b>METHODS</b>(99)Tc(m)-His10-Annexin V was prepared by one step direct labeling; radio-chemical purity (RCP) and radio-stability was tested. The binding of (99)Tc(m)-His10-Annexin V to apoptotic cells was validated in vitro using camptothecin-induced Jurkat cells. In vivo bio-distribution was determined in mice by dissection. The human H460 NSCLC tumor cell line (H460) tumor-bearing mice were treated with intravenous paclitaxel 24, 48 and 72 hours later. (99)Tc(m)-His10-Annexin V was injected intravenously, and planar images were acquired at 2, 4 and 6 hours post-injection on a dual-head gamma camera fitted with a pinhole collimator. Tumor-to-normal tissue ratios (T/NT) were calculated by ROI analysis and they reflected specific binding of (99)Tc(m)-His10-Annexin V. Mice were sacrificed after imaging. Caspase-3, as the apoptosis detector, was determined by flow cytometry, and DNA fragmentation was analyzed by the terminal deoxynucleotidytransferase mediated dUTP nick-end labeling (TUNEL) assay. Nonspecific accumulation of protein was estimated using bovine serum albumin (BSA). The imaging data were correlated with TUNEL-positive nuclei and caspase-3 activity.</p><p><b>RESULTS</b>(99)Tc(m)-His10-Annexin V had a RCP > 98% and high stability 2 hours after radio-labeling, and it could bind to apoptotic cells with high affinity. Bio-distribution of (99)Tc(m)-His10-Annexin V showed predominant uptake in kidney, relatively low uptake in myocardium, liver and gastrointestinal tract, and rapid clearance from blood and kidney was observed. The T/NT was significantly increased after paclitaxel treatment, whereas it was low in untreated tumors (T/NT = 1.43 ± 0.18). The %ID/g activity in Group 2 (24 hours), Group 3 (48 hours) and Group 4 (72 hours) after treatment was 2.55 ± 0.73, 3.35 ± 1.10, and 3.4 ± 0.96, respectively. Whereas in the non-treated group, Group 1, %ID/g was 1.10 ± 0.18. The radiotracer uptake was positively correlated to the apoptotic index (r = 0.852, P < 0.01), as well as caspase-3 activity (r = 0.816, P < 0.01).</p><p><b>CONCLUSION</b>This study addresses the dynamics and feasibility of imaging non-small cell lung tumor apoptosis using (99)Tc(m)- His10-Annexin V.</p>

The experimental study on anti-tumor effect of 131Ⅰ-Tyr-octreotide in nude mice bearing human non-small cell lung cancer / 中华核医学杂志

Objective Radionuclide-labeled low molecular weight polypeptide is reeently advocated for the diagnosis and treatment of malignant tumor. The purpose of this study was to evaluate the anti-tumor effect of 131Ⅰ-Tyr-octreotide in nude mice bearing human non-small cell lung cancer (NSCLC). Methods 131Ⅰ-Tyr-octreotide was prepared by Ch-T method. The radiochemical purity was measured and biodistribution was evaluated. The nude mice models bearing human NSCLC were studied and divided into four groups: group A injected 131Ⅰ-Tyr-octreotide through tail vein, group B injected normal saline, group C injected 131Ⅰ-Tyroctreotide through stroma and group D injected 131Ⅰ through stroma. The radioactivity ratio of tumor to normal tissue (T/NT) was calculated over region of interest (ROI). The tumor cell cycle and cell apoptosis were analyzed by flow cytometry (FCM), terminal deoxynucleotidyl transferase mediated dUTP-biotion nick end labeling (TUNEL) and histopathological analysis. Statistical analysis was performed with SPSS 11.0, and the comparison for difference between groups performed with one-way ANOVA analysis. Results The labeled radiochemical purity was (95.23±1.67)% and specific activity of 3.5×106Bq/ug. The biodistributiou showed high uptake in kidney, and low uptake in liver and spleen. The radioactive uptake in group C was higher than the other groups, and the retention time was longer. The T/NT was 52.74±0.13 after 24 h, which was much higher than that the other groups (group D: 8.90±0.23, group A: 6.42±0.02, q=628.81 and 664.33, all P<0.05). The resuits of tmnor cell cycle determined by FCM showed that the G1 phase was blocked mast remarkably in group C than the other groups [group C: (83.17±6.86)%, group A: (57.02±18.81)%, group D: (49.29±7.80)%, group B: (45.88±5.13)%, q=5.29, 6.86, 7.55, 1.56, 2.26, 0.69, all P<0.05]. Apeptotic cells were observed by TUNEL, and apoptotic body was detected by immuno-histochemical examination. Conclusions 131Ⅰ-Tyr-octreotide was easily labeled by Ch-T. 131Ⅰ-Tyr-octreotide could induce tumor cell apoptosis and inhibit the tumor cell of NSCLC. It might be a potential target-directed agent in NSCLC.

Technetium-99m labeled synaptotagmin I C2A detection of paclitaxel-induced apoptosis in non-small cell lung cancer / 中华肿瘤杂志

<p><b>UNLABELLED</b>Objective To evaluate the efficacy of 99mTc-labeled C2A probe in detection of apoptosis of non-small cell lung cancer (NSCLC) cells after chemotherapy.</p><p><b>METHODS</b>Imaging studies were performed in NSCLC H460-bearing mice. The mice were divided into 2 groups: the paclitaxel-treated group and control group. 99mTc-C2A was injected intravenously at 12, 24, 48 and 72 h after chemotherapy. Images were acquired at 3 h and 6 h after injection using a pinhole collimator. The regions of interest (ROI) were drawn in tumor area and contralateral nomal tissue, and the ratio of T/NT were caculated. The tumor sections were stained by HE and TUNEL (terminal deoxynucleotidyltransferase-mediated dUTP-nick-end labeling) staining to confirm the presence of apoptosis. Activated caspase-3 was also analyzed with flow cytometry.</p><p><b>RESULTS</b>Little uptake of 99mTc-C2A was found in baseline images, but tumor uptake increased very much after chemotherapy, the T/NT ratio was 1.79 +/- 0.34, 2.23 +/- 0.33 and 2.78 +/- 0.34, respectively. The T/NT ratio of control was 1.48 +/- 0.23. Tumor uptake (% ID/g) of 99mTc-C2A in chemotherapy groups were 2.82 +/- 0.90, 3.13 +/- 0.48 and 3.52 +/- 1.18, respectively. Tumor uptake (% ID/g) in the control group was 1.21 +/- 0.51. It in paclitaxel-treatment groups were 2.82 +/- 0.90, 3.13 +/- 0.48 and 3.51 +/- 1.18, respectively, significantly higher than that in untreated mice. Furthermore, the uptake of 99mTc-C2A correlated well with apoptotic index (r = 0.56, P < 0.01), and activated caspase-3 (r = 0.59, P < 0.01).</p><p><b>CONCLUSION</b>Our preliminary results demonstrated that 99mTc-C2A imaging in vivo for detection of cell death in solid tumors is feasible and well correlated with TUNEL staining and activated caspase-3. The C2A holds promise and warrants further development as a molecular probe to early predict cancer treatment efficacy.</p>