Differences and Similarities in TRAIL- and Tumor Necrosis Factor-Mediated Necroptotic Signaling in Cancer Cells

Abstract

Recently, a type of regulated necrosis (RN) called necroptosis was identified to be involved in many pathophysiological processes and emerged as an alternative method to eliminate cancer cells. However, only a few studies have elucidated components of TRAIL-mediated necroptosis useful for anticancer therapy. Therefore, we have compared this type of cell death to tumor necrosis factor (TNF)-mediated necroptosis and found similar signaling through acid and neutral sphingomyelinases, the mitochondrial serine protease HtrA2/Omi, Atg5, and vacuolar H⁺-ATPase. Notably, executive mechanisms of both TRAIL- and TNF-mediated necroptosis are independent of poly(ADP-ribose) polymerase 1 (PARP-1), and depletion of p38α increases the levels of both types of cell death. Moreover, we found differences in signaling between TNF- and TRAIL-mediated necroptosis, e.g., a lack of involvement of ubiquitin carboxyl hydrolase L1 (UCH-L1) and Atg16L1 in executive mechanisms of TRAIL-mediated necroptosis. Furthermore, we discovered indications of an altered involvement of mitochondrial components, since overexpression of the mitochondrial protein Bcl-2 protected Jurkat cells from TRAIL- and TNF-mediated necroptosis, and overexpression of Bcl-XL diminished only TRAIL-induced necroptosis in Colo357 cells. Furthermore, TRAIL does not require receptor internalization and endosome-lysosome acidification to mediate necroptosis. Taken together, pathways described for TRAIL-mediated necroptosis and differences from those for TNF-mediated necroptosis might be unique targets to increase or modify necroptotic signaling and eliminate tumor cells more specifically in future anticancer approaches.

ACKNOWLEDGMENTS

We thank Sabine Mathieu-Grützmacher and Parvin Davarnia for excellent technical assistance.

We declare that we have no competing interests.

J.S., S.P., J.F., C.A., T.P., H.K., A.T., I.S., and D.A. designed research; J.S., S.P., J.F.C., C.S., J.F., A.F., and J.P. performed research; J.S., S.P., J.F.C., C.S., J.F., A.F., J.P., I.S., H.K., A.T., S.S., and D.A. analyzed data; and J.S. and D.A. wrote the manuscript. All authors read and approved the final manuscript.

This work was supported by Deutsche Forschungsgemeinschaft SFB 877, project B2, Cluster of Excellence Inflammation at Interfaces EXC306-PMTP1 and EXC306-PWTP2 to D.A.; SFB 877, project B1, Cluster of Excellence Inflammation at Interfaces EXC306-WTP4 to S.S.; DFG grant SCHU733/14-1 to S.S. and J.F.; Deutsche Forschungsgemeinschaft grant SCHM1586/3-1 to I.S.; fellowship A/08/79433 from the German Academic Exchange Service DAAD and Klara und Werner Kreitz Stiftung to J.S.; CAU Forschungsförderung 2014-Junior to S.P.; and a Deutsche Krebshilfe grant to D.A. and H.K. (110055).