Biodistribution and preparation of technetium-99m-labeled D-D₃ monoclonal antibody against pro-gastrin-releasing peptide (₃₁₋₉₈) in mice / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>We previously reported that iodine-131((131)I)-labeled anti-pro-gastrin-releasing peptide (ProGRP(31-98)) monoclonal antibody D-D3 could selectively accumulate in the tumor sites of nude mice bearing small cell lung cancer (SCLC) xenografts. However, (131)I-D-D3 was cleared slowly from the body, and the best radioimmunoimaging time for SCLC was 72 - 96 hours after injection. The aims of this study were to radiolabel anti-ProGRP(31-98) D-D3 monoclonal antibody with technetium-99m ((99m)Tc) and to investigate the biodistribution of this antibody in healthy ICR mice.</p><p><b>METHODS</b>D-D3 was labeled with (99m)Tc via the 2-mercaptoethanol reduction method. (99m)Tc-D-D3 was purified by the gel column separation method. The labeling efficiency and radiochemical purity were measured by thin-layer chromatography. The immunological activity of (99m)Tc-D-D3 was determined with cell conjugation assays. (99m)Tc-D-D3 was injected into healthy ICR mice via a tail vein, and all the healthy ICR mice were sacrificed by cervical dislocation at a designated time. Then, the blood and major organs were removed and weighed, and counted in a gamma scintillation counter to determine the percentage of the injected dose per gram (%ID/g).</p><p><b>RESULTS</b>The labeling rate and the radiochemical purity of (99m)Tc-D-D3 were (73.87 ± 2.89)% and (94.13 ± 4.49)%, respectively. The immunobinding rates of (99m)Tc-D-D3 to the human small cell lung cancer NCI-H446 cell line and lung adenocarcinoma A549 cell line were (81.2 ± 2.37)% and (24.3 ± 1.46)%, respectively. The distribution data of normal ICR mice demonstrated that (99m)Tc-D-D3 was mainly distributed in the liver, kidney and lung, and less in the brain tissue and muscle.</p><p><b>CONCLUSIONS</b>(99m)Tc-D-D3 antibody not only had high radiochemical purity, but also had good stability both in vitro and in vivo, and maintained good immunological activity. (99m)Tc-D-D3 was metabolized mainly in the kidney and liver, and the blood radioactivity decreased rapidly. Thus, (99m)Tc-D-D3 is conducive to the radioimmunoimaging of SCLC.</p>

The experimental study of radionuclide imaging and treatment of cervical cancer mediated by hNIS gene transfection / 中华核医学杂志

Objective To explore the feasibility of imaging and treatment of cervical cancer xenograft model using 131I mediated by hNIS gene transfection. Methods The cervical cancer xenograft models were established with Hela-NIS( +) cells and Hela cells, respectively. Five Hela-NIS( +) xenograft models and five Hela xenograft models were dynamically imaged at 0.5, 1, 2, 4, 8, 16 and 20 h postinjection of 131I(7.4 MBq). Five Hela-NIS( +) xenograft models were imaged at 0. 5,1,2,4,8,16, 20 and 25 h postinjection of 99TcmO4-(11.1 MBq). Twenty Hela-NIS( +) cervical cancer xenograft models were randomly divided into four groups: Three 131I treating groups and one control group. The therapeutic effects of 131I at threelevels (74,111,148 MBq) were investigated following intraperitoneal injection. Results Hela-NIS( +)human cervical cancer xenografts were established successfully in nude mice. The Hela-NIS( +) xenografts significantly accumulated radioactivity after intraperitoneal injection of 131I, and the radioactivity was persistently present until 20 h postinjection, but Hela xenografts had no radioactive accumulation. The T/B value of the Hela-NIS( +) xenografts reached 17.34 at 8 h postinjection. The imaging with 99TcmO4- showed that the radioactivity was persistently present in Hela-NIS( +) xenografts for almost 25 h. The Hela-NIS( +)xenografts shrinked after 131I treatment. The inhibition ratios of tumor growth in 111 MBq and 148 MBq groups were both significantly higher than that of 74 MBq group (t: 2.74-5.75, P ＜0.05). Conclusions Hela-NIS( +) cervical cancer xenografts in nude mice could persistently accumulate 131I and 99TcmO4- and could be treated successfully with 131 I. 131 I treatment mediated by hNIS gene transfection could be a promising cancer treatment method.

Adenovirus-mediated and tumor-specific transgene expression of the sodium-iodide symporter from the human telomerase reverse transcriptase promoter enhances killing of lung cancer cell line in vitro / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The sodium-iodide symporter (NIS) protein can mediate the active radioiodine uptake. The human telomerase reverse transcriptase (hTERT) promoter is known to be selectively reactivated in majority of tumors and hence could be used for tumor targeting. We constructed a recombinant adenovirus containing the human sodium iodide symporter (hNIS) gene directed by the hTERT promoter, characterized the ability of infected cells in uptaking iodide, and explored the therapeutic efficacy of (131)I in a lung cancer cell line in vitro.</p><p><b>METHODS</b>The hTERT promoter was amplified by PCR from DNA isolated from log-phase HepG2 cells, subcloned into lineralized FL*-hNIS/pcDNA3, and then the hTERT-hNIS sequence was subcloned into the shuttle plasmid pAdTrack. The recombinant adenovirus Ad-hTERT-hNIS was constructed by AdEasy system. A positive control adenovirus Ad-CMV-hNIS and a negative control adenovirus Ad-CMV were created similarly. A549 cells were transduced with recombinant adenoviruses. (125)I uptake studies and sodium perchlorate suppression studies were used to confirm hNIS expression and function. Toxic effects of (131)I on tumor cells were studied by in vitro clonogenic assay.</p><p><b>RESULTS</b>We first successfully constructed an adenovirus mediated transgene expression system of the hNIS under the control of hTERT promoter. When infected with recombinant adenovirus constructs expressing hNIS directed by hTERT- and CMV-promoters (Ad-hTERT-hNIS and Ad-CMV-hNIS, respectively), the lung cancer cell line A549 had increased ability to uptake radioiodide up to 23- and 30-fold compared to the control parental cells, respectively. The radioiodide uptake ability of both the Ad-CMV-hNIS and Ad-hTERT-hNIS transduced cell lines were repressed 11-fold by sodium perchlorate (NaClO4). The subsequent in vitro clonogenic assay of the infected A549 cell line was further repressed to 23% (Ad-CMV-hNIS) and 30% (Ad-hTERT-hNIS) of the control group after receiving radioiodide for 7 hours (P < 0.001).</p><p><b>CONCLUSION</b>Our preliminary study indicates that an adenovirus mediated transgene expression system of the hNIS under the control of hTERT promoter has the potential to become an effective wide-spectrum yet highly specific anti-cancer strategy.</p>

Biodistribution and radioimmunoimaging of 131 I-Herceptin in healthy KM mice and nude mouse models bearing human ovarian cancer xenografts / 中华核医学杂志

Objective To study the biodistribution of anti-HER-2/neu monoclonal antibody Herceptin labeled by 131I(131I-Herceptin) in healthy KM mice and nude mice bearing human ovarian cancer xenografts and radioimmunoimaging (RII) of the nude xenografts-bearing mice.Methods 131I-Herceptin was prepared using Iodogen method.The labeling efficiency, radiochemical purity, stability and immunocompetence were measured.The percentage activity of injection dose per gram of tissue (%ID/g) and the radioactivity ratio of tumor to non-tumor tissue (T/NT) were calculated for each time point.The optimal time for imaging was investigated by comparing the 131I-Herceptin SPECT for the nude mouse models bearing ovarian cancer xenografts at different time points.Results The labeling efficiency and radiochemical purity of 131I-Herceptin were 89.8% and 98.4%, respectively.The labeling was stable and had good immunocompetence.131 I-Herceptin was cleared rapidly mainly through liver, spleen and kidneys, consistent with first order two-compartment model.The uptake of 131I-Herceptin in the tumors bearing human SKOV-3 xenografts was much higher than that in nontumor tissue.The% ID/g was 18.08 in the tumor at 24 h post injection.The T/NT ratio increased with time and was 27.27 at 72 h post injection.The tumors in nude mice bearing SKOV-3 xenografts could be visualized on 131I-Herceptin SPECT imaging 2 h post injection; definitely identiffed 48 h post injection and the radioactivity ratio of tumor to contralateral tissue was 11.44 at 120 h post injection.However, the tumor in nude mice bearing HO-8910 xenografts did not show abnormal uptake of 131 I-Herceptin at each time point.Conclusions 131 I-Herceptin is a good radiopharmaceutical targeting SK-OV-3 xeuografts and it may be useful in imaging carcinoma of ovary and target therapy of its metastases with high HER-2/neu expression.