The Effect of Combination Therapy with OK-432 and rIL-2 by Intrasplenic Administration to Inhibit Micrometastasis in the Liver on Metastatic Model of Colorectal Carcinoma

Yuichi Arimoto, Yong-Suk Chung, Nobuya Yamada, Kiyoshi Maeda, atsunori Nitta, Koji Hirayama, Tetsuji Sawada, Bunzo Nakata, Yukio Nishiguchi, Masahiro Okuno*, Michio Sowa

The First Department of Surgery, Osaka City University Medical School, Surgery of Osaka City General Medical Center*

An experimental liver micrometastatic model of colorectal carcinoma was developed and the effects of combination therapy with OK-432 and γIL-2 by splenic injection to inhibit liver metastasis, a critical element of prognosis of colorectal carcinoma, were determined. Micrometastasis in the liver was observed on day7 after transportal inoculaiton of colon 26 cells, which are murine colon carcinoma cells. Although the mice were treated with drugs after the development of micrometastasis in the liver, both treatment with each drug singly and in combination resulted in significant inhibition of the development of liver metastasis compared with the control (p<0.005). Combined treatment significantly inhibited the development of liver metastasis compared with OK-432 alone (p<0.025). The anti-tumor activity of splenic cells injected with drugs became stronger. These results suggest that intrasplenic drug injection was effective in inhibiting liver metastasis.

Key words
colorectal carcinoma, micrometastatic liver tumor, OK-432, recombinant interleukin-2, BRM therapy

Reprint requests
Yuichi Arimoto First Department of Surgery, Osaka City University Medical School
1-5-7 Asahimachi, Abeno-ku, Osaka 545 JAPAN

Accepted
November 9, 1994

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