Anti-sense oligonucleotide labeled with technetium-99m using hydrazinonictinamide derivative and N-hydroxysuccinimidyl S-acetylmercaptoacetyltriglycline: a comparison of radiochemical behaviors and biological properties.

AIM: To explore and compare the radiochemical behavior and biological property of anti-sense oligonuc-leotide (ASON) labeled with technetium-99m using N-hydroxysuccinimidyl S-acetylmercaptoacetyltriglycline (NHS-MAG(3)) and hydrazinonictinamide derivative (HYNIC). METHODS: After HYNIC and NHS-MAG(3) were synthesized, ASON was labeled with technetium-99m using HYNIC and NHS-MAG(3) as a bifunctional chelator. The in vivo and in vitro stability, binding rates of labeled compounds to serum albumen, biodistribution of (99m)Tc-MAG(3)-ASON and (99m)Tc-HYNIC-ASON in BALB/C mouse and its HT29 tumor cellular uptake were compared. RESULTS: The labeling efficiency and stability of (99m)Tc-MAG(3)-ASON were significantly higher than those of (99m)Tc-HYNIC-ASON (P = 0.02, and P = 0.03, respectively). (99m)Tc-MAG(3)-ASON had a significantly lower rate of binding to serum albumen than (99m)Tc-HYNIC-ASON (P < 0.05). In contrast to (99m)Tc-HYNIC-ASON, the biodistribution of (99m)Tc-MAG(3)-ASON was significantly lower in blood, heart, liver and stomach (P < 0.05), slightly lower in intestines and spleen (P > 0.05) and significantly higher in lung and kidney (P < 0.05). The HT29 tumor cellular uptake rate of (99m)Tc-MAG(3)-ASON was significantly higher than that of (99m)Tc-HYNIC-ASON (P < 0.05). CONCLUSION: (99m)Tc-MAG(3)-ASON shows superior radiochemical behaviors and biological properties than (99m)Tc-HYNIC-ASON. (99m)Tc-MAG(3)-ASON is a potential radiopharmaceutical agent for in vivo application.

Targeting radioimmunotherapy of hepatocellular carcinoma with iodine (131I) metuximab injection: clinical phase I/II trials.

PURPOSE: HAb18G/CD147 is a hepatocellular carcinoma (HCC)-associated antigen. We developed iodine (131I) metuximab injection (Licartin), a novel 131I-labeled HAb18G/CD147-specific monoclonal antibody Fab'2 fragment, and evaluated its safety, pharmacokinetics, and clinical efficacy on HCC in Phase I/II trials. METHODS AND MATERIALS: In a Phase I trial, 28 patients were randomly assigned to receive the injection in 9.25-, 18.5-, 27.75-, or 37-MBq/kg doses by hepatic artery infusion. In a multicenter Phase II trial, 106 patients received the injection (27.75 MBq/kg) on Day 1 of a 28-day cycle. Response rate and survival rate were the endpoints. RESULTS: No life-threatening toxic effects were found. The safe dosage was 27.75 MBq/kg. The blood clearance fitted a biphasic model, and its half-life was 90.56-63.93 h. In the Phase II trial, the injection was found to be targeted and concentrated to tumor tissues. Of the 73 patients completing two cycles, 6 (8.22%) had a partial response, 14 (19.18%) minor response, and 43 (58.90%) stable disease. The 21-month survival rate was 44.54%. The survival rate of progression-free patients was significantly higher than that of patients with progressive disease after either one or two cycles (p < 0.0001 or p = 0.0019). CONCLUSION: Iodine (131I) metuximab injection is safe and active for HCC patients.

[Preparation and biodistribution of VIP-125I-ASON].

OBJECTIVE: To prepare VIP-125I-ASON and investigate the possibility of using it as an agent for diagnostic imaging and therapy of colon carcinoma. METHODS: The iodination of a 15-base single-stranded antisense oligonucleotide (ASON) complementary to C-myc oncogene mRNA was carried out in the presence of TICl3. The radiolabeled oligonucleotide was complexed with a VIP-polylysine conjugate under certain condition. 3-5 microCi VIP-125I-ASON was injected into the tail vein of the BALB/c nude mice bearing transplanted HT29 colon carcinoma; the nude mice were killed at specific intervals after injection, and the biodistrbution of VIP-125I-ASON in the organs were calculated. RESULTS: The biodistributed experiment showed that the 125I-ASON was excreted by kidney mostly and by liver and spleen in part. The results of studies after the injection of VIP-125I-ASON differed from those of unconjugated 125I-ASON. The conjugation of VIP to the ASON resulted in a decrease in the plasma clearance of the radiopharmaceutical, which may be due to the reduction in the renal clearance of the ASON. The highest uptake of tumor tissue (5.89% ID/g at 2 h) was significantly higher than that in nude mice given unconjugated ASON (P < 0.05). Tumor to blood ratios and tumor to muscle ratios were optimal at 4 h. CONCLUSION: VIP-125I-ASON has desirable stability and higher uptake in tumor. It may provide a new sensitive mean for diagnostic antisense imaging and radiotherapy of tumor in the future.

Antisense imaging of colon cancer-bearing nude mice with liposome-entrapped 99m-technetium-labeled antisense oligonucleotides of c-myc mRNA.

AIM: To investigate the feasibility for antisense imaging of the colon cancer with liposome-entrapped 99 m-technetium labeled antisense oligonucleotides as tracers. METHODS: Fifteen mer single-stranded aminolinked phosphorothioate antisense oligonucleotides of c-myc mRNA were labeled with 99mTc-pertechnetate, then purified and finally entrapped with liposomes to form the labeling compounds, liposome-entrapped 99mTc-labeled antisense oligonucleotides. The LS-174-T cells (colon of adenocarcinoma cell line) were incubated with the labeling compounds to test the uptake rates of LS-174-T cells. Later on, a model of 30 tumor bearing nude mice was constructed by inoculating with 5 x 10(6) of LS-174-T cells at right flank of each nude mouse. About 10 d later, the model were administered by intravenous injection of the liposome-entrapped 99mTc-labeled antisense oligonucleotides. Then some of the tumour bearing nude mice were sacrificed at 0.5, 1, 2, and 4 h after intravenous injection, and proper quantity of liver, spleen, tumor, etc. was obtained. The tissues were counted in a gamma counter, and after correction for decay and background activity, expressed as a percentage of the injected dose. The others whose anterior and posterior whole-body scans were obtained at 1, 1.5, 2, 4, 6 and 24 h with a dual-head bodyscan camera equipped with parallel-hole low-energy collimaters. The ratios of radioactive counts in tumor to that in contralateral equivalent region of abdomen were calculated. RESULTS: The uptake rates of LS-174-T cells for liposome-entrapped 99mTc-labeled antisense oligonucleotides increased as time prolonged and reach the peak (17.77 +/- 2.41%) at 7 h. The biodistributions showed that the radioactivity in the tumor (13.46 +/- 0.20%) of injected dose was the highest at 2 h of intravenous injection of liposome-entrapped 99mTc-labeled antisense oligonucleotides, and then decreased sharply to 4.58 +/- 0.45% at 4 h. The tumor was shown clearly in the whole-body scan at 2 h of intravenous injection. The ratios, radioactive counts in tumor to that in contralateral equivalent region of abdomen (1.7332 +/- 0.2537), was the highest one at 2 h after intravenous injection of liposome-entrapped 99mTc-labeled antisense oligonucleotides. CONCLUSION: The liposome-entrapped 99mTc-labeled antisense oligonucleotides deserve being developed into radiopharmaceutics for the colon cancer imaging.

131I-recombinant human EGF has antitumor effects against MCF-7 human breast cancer xenografts with low levels of EGFR.

This study investigated the inhibitory action of (131)I-recombinant human EGF ((131)I-rhEGF) on MCF-7 human breast cancer tumor development in nude mice. The activity and tumor uptake of (131)I-rhEGF was measured by tissue distribution assay, and its effect on tumor growth was measured by monitoring tumor size after treatment with (131)I-rhEGF. Changes in tumor cell ultrastructure were observed by transmission electron microscopy (TEM), and pathological changes in tumor tissue were observed by light microscopy. The tissue distribution assay revealed that (131)I-rhEGF was markedly absorbed by the tumor and reached its maximal uptake rate (16.73%ID. g(-1)) at 120 hours at which point the drug concentration in the tumor was 11.1-fold, 8.1-fold, and 6.6-fold higher than that in blood, liver, and kidneys, respectively. Tumor size measurements showed that tumor development was significantly inhibited by intravenously and intratumorally injected (131)I-rhEGF. Tumor inhibition rates (82.0% and 80.7%, respectively) were significantly higher than those of tumors treated with (131)I (7.49%) and (131)I-HSA (6.91%; P < 0.05). TEM and light microscopy revealed that intravenous and intratumoral injection of (131)I-rhEGF could significantly damage and ultimately kill tumor cells. Our results suggest that (131)I-rhEGF suppresses development of xenografted breast cancer cells in nude mice, providing a novel candidate for receptor-mediated targeted radiotherapy.

[The radiolabeling property of oligonucleotide with 99mTc using NHS-MAG3 as a chelator].

OBJECTIVE: To explore the radiolabeling property of oligonucleotide with 99mTc using NHS-MAG3 as a bifunctional chelator. METHODS: Three 15-base single-stranded amine-derivitized oligonucleotides, which were antisense(ASON), sense(SON) and mismatched oligonucleotides(MON) of c-myc oncogene mRNA, were coupled with NHS-MAG3 and labeled with 99mTc. The labeled oligonucleotide was purified by Sephadex G25 column chromatogram, then the stability was evaluated. The labeling efficiency of ON-MAG3 was assessed 15 days, 1 month and 2 months after storage at -20 degrees C. The binding rate of 99mTc-ON with plasma protein was measured by the trichloroacetic acid precipitation method. RESULTS: The average labeling efficiency of 99mTc-ASON, 99mTc-SON and 99mTc-ON was 68.41%, 66.24% and 69.38% respectively, and the radiochemical purity was 96.98%, 95.34% and 94.62%. 99mTc-ON was stable when placed at room temperature or incubated in human serum at 37 degrees C. The labeling efficiency of ON-MAG3 did not significantly change 2 months after storage at -20 degrees C. The plasma protein binding rate of 99mTc-ON was lower than 13%. CONCLUSION: 99mTc-ON labeled with NHS-MAG3 method showed superior radiochemical characteristics. The labeling efficiency and radiochemical purity were desirable. The label was stable in serum and the binding with plasma protein was low. 99mTc-ON could be a sort of potential radiopharmaceutical for in vivo applications.