Antitumor Effect of Water in Oil Type Emulsion Encapsulating OK-432 and Interleukin-2 on Liver Metastasis of Colorectal Cancer in Mice

Kunihiko Yasuda, Yasuyuki Sugiyama, Motohisa Katou, Souichi Ri and Shigetoyo Saji

Second Department of Surgery, Gifu University School of Medicine

The effects of intrasplenic administration of an encapsulated emulsion of OK-432 and IL-2 (BILE) were investigated against metastatic liver tumor of colon 26 cells, following inoculation intraportally to BALB/c mice. Results: (1) OK-432 was observed around the metastatic nodules of the liver on day 10 following both BILE and BRM administration. However it wan no longer detected on day 14 in the BRM group. (2) The number of metastatic nodules in the liver was significantly lower in the BILE group as compared with that in the BRM and BS groups. (3) The cytotoxic activity of hepatic lymphocytes against the colon 26 cells (specific) gradually increased until day 10 of tumor inoculation in both the BILE and BS groups. However it showed a gradual decrease until day 14, more significantly in the BRM group. (4) THE NK cell activity evaluated with YAC-1 showed the tendency toward a linear pattern of increase in the BILE group, however, it remained almost unchanges in the BRM group. From the above results, it is suggested that transportal infusion of an emulsion of OK-432 and IL-2 was effective in activating the immunological functions of the liver and induced supression of liver metastases. It could also be recommended as one of the treatment options for liver metastases in patients with colorectal cancer.

Key words
OK-432, Interleukin (IL) -2, drug delivery system (DDS ), colon 26, metastatic liver tumor

Reprint requests
Kunihiko Yasuda Second Department of Surgery, Gifu University School of Medicine 40 Tsukasamachi, Gifu, 500-8705 JAPAN

Accepted
May 23, 2000

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