Figure 1.

Synergistic or semiadditive effects of 5‐aza‐CdR with anticancer drugs in gastric cell lines. A synergistic antiproliferative effect in response to a combination of 5‐aza‐CdR with SN38 or GEM was observed in both OCUM‐2M and MKN‐74 cells. In MKN‐74 cells, the combination of 5‐aza‐CdR with OXA also showed a synergistic antiproliferative effect. A semiadditive antiproliferative effect was observed in response to a combination of 5‐aza‐CdR with OXA or PTX in OCUM‐2M, and with PTX in MKN‐74. No significant effect was observed in response to a combination of 5‐aza‐CdR with 5‐FU in either cell line. Each anticancer drug was added at the IC₅₀ for each cell line. The synergistic, semiadditive, and antagonistic interactions were determined when the value was less than the expected value, more than the expected value but less than the drugs’ value, and more than the drugs’ value, respectively. The expected value of the combined effects (%) = effects of anticancer drug/control × effects of 5‐aza‐CdR/control × 100. The results are presented as the mean of three independent experiences, and the bars indicate the standard deviation. *P < 0.05 and **P < 0.01, compared with each anticancer drug alone. Exp, an expected additive value; N.S., not significant.