FIGURE 3.

RIS exposure attenuates proapoptotic signaling molecules in vivo. A, allograft assay with CMT-93 cells pre-exposed to DON. CMT-93 C57BL/6 mouse colon cancer cells pre-exposed to 500 ng/ml DON for 24 h were dissociated into single cells with trypsin, and 5 × 10⁶ cells resuspended with 200 μl of PBS were injected subcutaneously into 14-week-old male C57BL/6 mice. Seven days later, 100 mg/ml 5-FU was intraperitoneally injected, and tumors were excised surgically 24 h later. The tumor volume was calculated as tumor volume = π/6 × major diameter (W) × minor diameter (L)², presented by vertical scatter plot, and statistically analyzed by unpaired two-tailed t test (bottom panel). The difference in tumor volume was statistically significant (**, p = 0.0022). Con, control. B, a histological section of allograft tumors was analyzed by immunohistochemistry with MIC-1, EGR-1, and ATF3. 3,3′-diaminobenzidine intensity versus hematoxylin was quantitatively assessed by HistoQuest software and statistically analyzed by unpaired two-tailed t test (bottom panel). **, p < 0.01; ***, p < 0.001.