In some cellular systems, particularly neurons, amyloid precursor-like protein 2 (APLP2), and its highly homologous family member amyloid precursor protein (APP), have been linked to cellular growth. APLP2 and APP undergo regulated intramembrane proteolysis to produce C-terminal fragments. In this study, we found comprehensive expression of APLP2 C-terminal fragments in a panel of pancreatic cancer cell lines; however, APP C-terminal fragments were notably limited to the BxPC3 cell line. Extensive glycosaminoglycan modification on APLP2 was also found in the majority of pancreatic cancer cell lines. Glycosaminoglycan-modified and -unmodified APLP2, and particularly APLP2 C-terminal fragments, also demonstrated increased expression in oncogene-transformed pancreatic ductal cells. Additionally, elevated APLP2 levels were confirmed in human pancreatic cancer tissue. Downregulation of APLP2 and APP expression, alone or in combination, caused a decrease in the growth of a pancreatic cancer cell line with representatively low APP C-terminal fragment expression, the S2-013 cell line. Furthermore, we found that treatment with β-secretase inhibitors to block formation of APLP2 C-terminal fragments decreased the growth and viability of S2-013 cells, without affecting the survival of a non-transformed pancreatic ductal cell line. In conclusion, our studies demonstrate that abundant APLP2, but not APP, C-terminal fragment expression is conserved in pancreatic cancer cell lines; however, APP and APLP2 equally regulated the growth of S2-013 pancreatic cancer cells. Chiefly, our discoveries establish a role for APLP2 in the growth of pancreatic cancer cells and show that inhibitors preventing APLP2 cleavage reduce the viability of pancreatic cancer cells.
Peters, H. L., Tuli, A., Wang, X., Liu, C., Pan, Z., Ouellette, M. M., … Solheim, J. C. (2012). Relevance of amyloid precursor-like protein 2 C-terminal fragments in pancreatic cancer cells. International Journal of Oncology, 41(4), 1464–1474. https://doi.org/10.3892/ijo.2012.1553