Distribution of111 in-bleomycin complex in small cell lung cancer cells by autoradiography

Indium-111-bleomycin complex in squamous cell cancer xenograft tumors of nude mice

INTRODUCTION

Labeling of bleomycin with Auger-emitter Indium-111 increases cytotoxicity in squamous cell cancer (SCC) cell lines, as we have reported earlier. In this study, we investigated whether (111)In- BLMC is toxic and effective in vivo among SCC-xenografted mice. The influence of (111)InBLMC on the squamous cell carcinoma cell cycle stimulated interest.

MATERIALS AND METHODS

In an animal experiment, 10 SCC-xenografted mice were used, two for demonstrating targeting in gamma-camera images, eight for intraperitoneally receiving NaCl, BLM, or (111)InBLMC as therapy. After a 2-week follow-up, the tumors were analyzed for proliferation (mitoses, Ki-67). DNA flow cytometric analysis was carried out from tumor samples and three UT-SCC cell lines.

RESULTS

Tumors were observed on gamma-camera images in xenografted mice after a (111)InBLMC injection. The UT-SCC-19A-xenografted mouse had a T/non-T uptake of 7.54 at 4 hours after the injection. At the end of the therapeutic trial, the mice were alive. In spite of a small number of animals, our findings indicate that BLM and (111)InBLMC seem to be more effective than NaCl in reducing tumor size. The proliferative activity was strong in BLM and in (111)InBLMC groups, indicating regrowth of the tumors. In DNA analysis, the percentages of cells in the G2/M-phases increased after exposure to BLM and particularly to (111)InBLMC in all three cell lines.

CONCLUSIONS

The effect of BLM is preserved after the adding of Auger-emitter In-111. Tumor-seeking (111)InBLMC can be administered safely at tumor-decreasing concentrations in xenograft head and neck cancers. To demonstrate the antitumor effect of (111)InBLMC, the experiments should be extended to include a larger number of mice. BLM, and especially (111)InBLMC, seems to induce alteration in the cell cycle by producing a G2/M block. The verification of the result requires repeated in vitro experiments.

Kinetics of 111In-labeled bleomycin in patients with brain tumors: compartmental vs. non-compartmental models

The kinetics of an indium-111 labeled bleomycin complex (111In-BLMC) after rapid intravenous injection in patients with brain tumors was quantified by using compartmental and non-compartmental models. The models were applied to data obtained from 10 glioma, one meningioma, and one adenocarcinoma brain metastasis patients. Blood and urine samples from all the patients and tumor samples from three patients were collected. The mean transit time of 111In-BLMC in the plasma pool was 14 +/- 7 min without and 1.8 +/- 0.6 h when accounting for recirculation, and 13 +/- 4 h in the total body pool. The mean plasma clearance of 111In-BLMC was 0.3 +/- 0.1 m/blood/min and the mean half-life in urine was 3.5 +/- 0.6 h. The mean transfer coefficients for the open three-compartmental model were: excretion from plasma = 0.02 +/- 0.01, from depot to plasma = (12 +/- 9)*10(-4), from plasma to depot = 0.01 +/- 0.01, from tumor to plasma = 0.39 +/- 0.19 and from plasma to tumor = 1.11 +/- 0.57, all in units minute-1. The mean turnover time from the tumor was 4.5 +/- 2.7 min and from the depot 20 +/- 8 h. It is concluded that both compartmental and non-compartmental models are sufficient to describe the kinetics of indium-111 labeled bleomycin complex. The non-compartmental model is more practical and to some extent more efficient in describing the in vivo behaviors of 111In-BLMC than the compartmental model. The compartmental model used provides estimates of both extraction and excretion from the plasma and tumor.

Imaging and staging of head and neck cancer using a low pH In-111-bleomycin complex

Bleomycin (BLM), a natural antibiotic toxic to dividing cells has been used for treatment of several forms of cancer. BLM has been labelled with various cations but most have turned out to be unstable in vivo. In-BLM has demonstrated high bone marrow uptake, but by using an In-111-bleomycin complex (BLMC) formed at low pH, the low in vivo stability and high bone marrow uptake can be avoided. Our premise is to combine radiotherapy and chemotherapy by using radionuclide-BLMC. In this study we used In-111-A'2a-c-BLMC in 28 head and neck cancer patients. Scintigraphic findings were compared to those of surgery, pre-operative radiology and proliferation markers. The injected patient activity was approximately 85 MBq, 100 MBq/mg. The half-life of In-111 activity in serum varied from 1.5 to 3.1 h, and in urine from 1.4 to 3.7 h. More than 95% of the urine activity was excreted within 24 h. From biopsies obtained from surgical specimens of 22 patients the absolute uptakes in tumour tissues varied between 0.10 and 0.95 x 10(-3)% ID/g. Uptakes in normal tissues varied from 0.01 to 0.32 x 10(-3)% ID/g, and were always lower than in malignant tissues of the same patients. All patients were examined on the injection day with ultrasonography of the neck. Using In-111-BLMC we missed small metastatic lymph nodes (< 1 cm) in 2 patients, but there were no false positive findings. The critical organ from the dosimetric point of view was the kidney. The absorbed radiation doses with these injected activities were 19 mGy in liver, 75 mGy in kidney and 1.0 mGy in whole body (5 h mean residence time). Our results indicate that In-111-BLMC targets head and neck cancer, and identifies metastatic spread. It could possibly be applied with higher activities for adjuvant Auger-electron therapy of head and neck cancer.

Indium-111 bleomycin complex for radiochemotherapy of head and neck cancer--dosimetric and biokinetic aspects

Bleomycin (BLM) is used for the treatment of head and neck cancer. In order to improve the effectiveness of this chemotherapeutic drug, BLM was combined with indium-111. A complex of these agents (111In-BLMC), formed at low pH, was injected intravenously into ten head and neck cancer patients in escalating activities of 75, 175 and 375 MBq. The internally delivered dose to the tumours varied from 0.20 to 2.73 mGy at 75 MBq, from 0.33 to 2.51 mGy at 175 MBq, and from 0.87 to 31.3 mGy at the 375 MBq activity level. Uptake of radioactivity was 0.45+/-0.24x10(-3)% ID/g in primary tumours and 0. 52+/-0.20x10(-3)% ID/g in metastases (at 48 h). Tumour volumes varied from 0.51 to 49.0 cm3. The radioactivity half-lives in the tumours were 30+/-7 h. The activity distribution and penetration into tumour tissue were not affected by increasing the injected activity. There was a positive correlation between BLMC uptake and Ki-67/Mib activity as well as number of mitoses in tumour tissue. These data indicate that 111In-BLMC has potential as a radiochemotherapeutic agent in head and neck cancer and that adjuvant Auger-electron therapy is possible using 114mIn-labelled BLMC.

Chromosome aberrations of human small cell lung cancer induced by a new 111In-bleomycin complex

A new 111Indium labeled bleomycin complex (111In-BLMC) was prepared and found to be effective for tumor imaging and therapy both in mouse glioma and human small cell lung cancer (SCLC) cells. Chromosome aberrations were studied in human SCLC cells to explore its mechanisms of killing cancer cells. SCLC cells (N417) were exposed to 111In-BLMC, BLM, or 111InCl3 (for control) for 1 hour, treated with colcemid, and chromosomal changes were analyzed. A dramatic increase in chromatic gaps, breaks, chromosome breaks, double minutes, rings, triradii, quadriradii, and chromosome stickiness were observed in the cells treated by 111In-BLMC compared to BLM or 111InCl3. These results indicated that 111In-BLMC has therapeutic potential for combination chemo-radiotherapy of cancer (e.g., by Auger electrons and local energy deposition).