[Correlation between intracellular cyclic AMP level and cytotoxic sensitivity to anti-tumor-associated antigen antibody in rat fibrosarcoma cells].

We investigated the intracellular cyclic AMP (cAMP) level and cytotoxic sensitivity to anti-tumor-associated antigen (anti-TAA) antibody in transplantable rat fibrosarcoma cells with regard to each of three days following ip transplantation. The cytotoxic sensitivity of the 3-methylcholanthrene (MCA)-induced transplantable fibrosarcoma KMT-17 cells to anti-TAA antibody decreased daily after ip transplantation in syngeneic WKA/Hok rats. In contrast, the intracellular cAMP level of the tumor cells increased daily after ip transplantation, and the cAMP level of 3-day-old KMT-17 tumor cells (1.31 pmol/10(6) cells) was statistically (p less than 0.01) higher than that of 1-day-old tumor cells (1.01 pmol/10(6) cells). This phenomenon disappeared, however, after artificial infection of the tumor cells with Friend murine leukemia virus (F-MuLV). The cytotoxic sensitivity of F-MuLV-infected KMT-17 (FV-KMT-17) tumor cells to anti-TAA antibody did not decrease and no elevation of the intracellular cAMP level was observed (0.92-0.97 pmol/10(6) cells), regardless of the number of days after ip transplantation. The cytotoxic sensitivity of KMT-17 and FV-KMT-17 tumor cells to anti-TAA antibody was therefore in inverse proportion to the intracellular cAMP levels of the tumor cells.(ABSTRACT TRUNCATED AT 250 WORDS)