Augmented Susceptibility of CDDP-Treated Human Pancreatic Cancer Cell Line, PH101, to Lysis by Effector Lymphocytes

Yoshiyuki Yamaguchi, Kousuke Noma, Eiji Miyahara, Mahito Funakoshi, Ikuhiro Takashima, Tetsuya Toge

Department of Surgical Oncology, Research Institute for Rediation Biology and Medicine, Hiroshima University

Augmentation by CDDP of susceptibility of a human pancreatic cancer cell line, PH101, to lysis by effector lymphocytes was studied in vitro. Susceptibility of PH101 against lysis by lymphokine-activated killer (LAK) cells was significantly augmented after treatment of tumor cells with interferon (IFN)-gamma or CDDP. Flow cytometric analysis revealed that the HLA-class 1 and ICAM-I antigens on PH101 cells were upregulated by IFN-gamma but not by CDDP treatment. Cold target inhibition assay showed that lysis of CDDP-treated PH101 cells was significantly suppressed by the addition of CDDP-treated, but less by CDDP-untreated cold targets at the effector phase of the cytotoxicity assay. It is suggested that modulation of unknown target determinant(s) on tumor cells was involved in the CDDP-induced augmentation of tumor cell susceptibility to lysis by anti-tumor effector lymphocytes.

Key words
CDDP, PHLA-class 1, ICAM-1, LAK, IFN-gamma

Reprint requests
Yoshiyuki Yamaguchi Department of Surgical Oncology, Research Institute for Radiation Biology and Medicine, Hiroshima University
1-2-3, Kasumi, Minami-ku, Hiroshima, 734 JAPAN

Accepted
October 12, 1994

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