MAPK8 and malignant colon neoplasm: To further investigate whether JNK plays a critical role in snake venom toxin-induced up-regulation of DR4 and DR5, we pretreated the colon cancer cells with SP600125, a JNK inhibitor (5 and 10 μM) for 1 h, and then these cells treated with snake venom toxin (1 μg/ml) for 24 h to assess cell viability and DR4 and DR5 expression.