PT  - JOURNAL ARTICLE
AU  - Koyama, Keitaro
AU  - Fujiwara, Kentaro
AU  - Kitada, Takayuki
AU  - Takahashi, Miwako
AU  - Momose, Toshimitsu
TI  - Radioimmunotherapy for small cell lung cancer utilizing newly developed Y-90 labeled anti-ROBO1 antibody
DP  - 2013 May 01
TA  - Journal of Nuclear Medicine
PG  - 1369--1369
VI  - 54
IP  - supplement 2
4099  - http://jnm.snmjournals.org/content/54/supplement_2/1369.short
4100  - http://jnm.snmjournals.org/content/54/supplement_2/1369.full
SO  - J Nucl Med2013 May 01; 54
AB  - 1369 Objectives ROBO1 (1) is the target cell membrane antigen and highly expressed in human small cell lung cancer (SCLC). SCLC is known as refractory cancer and there is a need for novel treatment for SCLC. In this study, the anticancer effect of radioimmunotherapy (RIT) utilizingY-90 anti-ROBO1 IgG was evaluated by the changes of tumor volume and micro-PET imaging with F-18 FDG in xenograft mice. Methods Anti-ROBO1 IgG was radiolabeled with Y-90 via the chelating agent DOTA. As target tumor cell, NCI-H69, SCLC cell line, was used. It was confirmed that ROBO1 was expressed on the surface of NCI-H69 cell line by immunohistochemical staining. For RIT, the tumor-bearing mice were injected with 0.18 mCi of Y-90 anti-ROBO1 IgG. Tumor volume size was measured every few days. F-18 FDG PET imaging of treated mice was performed on a microPET every eight days. Tail vein blood was sampled and the number of blood cells was estimated by fully automated blood cell counter. In addition, the experiment with RIT to escalate radioactivity of Y-90 anti-ROBO1 IgG was performed. Results When RIT for SCLC tumor-bearing mouse was performed by administering 0.18 mCi of Y-90 anti-ROBO1 IgG, the significant reduction of tumor volume size was observed and in 20 days after administration it reduced to 6% of starting volume. Inhibition of tumor proliferation was attained during four weeks after administration. By PET imaging, it was confirmed that the accumulation of F-18 FDG to treated tumor was reduced and decreased proliferative ability was implied. Though the transient hematocytopenia was observed owing to myelosuppression associated with radiation, blood cells were recovered to nearly normal in late phase of observation. When amount of radioactivity of Y-90 anti-ROBO1 IgG was escalated from 0.06 mCi to 0.23 mCi, dose-dependent antitumor effect was confirmed. Conclusions By administering Y-90 anti-ROBO1 IgG, the significant reduction of SCLC tumor volume was attained. It is suggested that Y-90 anti-ROBO1 IgG can be useful for RIT for SCLC.