p38γ Activation and BGP (Biliary Glycoprotein) Induction in Primates at Risk for Inflammatory Bowel Disease and Colorectal Cancer-A Comparative Study with Humans.

Colorectal cancer (CRC) is a common cause of cancer-related deaths largely due to CRC liver metastasis (CRLM). Identification of targetable mechanisms continues and includes investigations into the role of inflammatory pathways. Of interest, MAPK is aberrantly expressed in CRC patients, yet the activation status is not defined. The present study assessed p38γ activation in CRC patients, cancer cells, and tissues of cotton top tamarin (CTT) and common marmoset (CM). The primate world is an overlooked resource as colitis-CRC-prone CTT are usually inure to liver metastasis while CM develop colitis but not CRC. The results demonstrate that p38γ protein and phosphorylation levels are significantly increased in CRC patients compared to normal subjects and CTT. Furthermore, p38γ phosphorylation is significantly elevated in human CRC cells and hepatoblastoma cells but not in CM colon. Additionally, carcinoembryonic antigen (CEA) and biliary glycoprotein (BGP) are induced in the CRC patients that showed p38γ phosphorylation. Inhibition of p38 MAPK in CRC cells showed a significant decline in cell growth with no effect on apoptosis or BGP level. Overall, p38γ is activated in CRC tumorigenesis and likely involves CEA antigens during CRLM in humans but not in the CTT or CM, that rarely develop CRLM.