Impact of p53 status on TRAIL-mediated apoptotic and non-apoptotic signaling in cancer cells.

Anna Willms,Ufuk Mert,Dieter Adam,Justyna Sosna,Hella Schittek,Sascha Rahn,Anna Trauzold,Andreas Krieg

doi:10.1371/journal.pone.0214847

Anna Willms, Ufuk Mert + Show 6 more

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https://doi.org/10.1371/journal.pone.0214847

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Abstract

Due to their ability to preferentially induce cell death in tumor cells, while sparing healthy cells, TNF-related apoptosis-inducing ligand (TRAIL) and agonistic anti-TRAIL-R1 or anti-TRAIL-R2-specific antibodies are under clinical investigations for cancer-treatment. However, TRAIL-Rs may also induce signaling pathways, which result in malignant progression. TRAIL receptors are transcriptionally upregulated via wild-type p53 following radio- or chemotherapy. Nevertheless, the impact of p53 status on the expression and signaling of TRAIL-Rs is not fully understood. Therefore, we analyzed side by side apoptotic and non-apoptotic signaling induced by TRAIL or the agonistic TRAIL-R-specific antibodies Mapatumumab (anti-TRAIL-R1) and Lexatumumab (anti-TRAIL-R2) in the two isogenic colon carcinoma cell lines HCT116 p53+/+ and p53-/-. We found that HCT116 p53+/+ cells were significantly more sensitive to TRAIL-R-triggering than p53-/- cells. Similarly, A549 lung cancer cells expressing wild-type p53 were more sensitive to TRAIL-R-mediated cell death than their derivatives with knockdown of p53. Our data demonstrate that the contribution of p53 in regulating TRAIL-R-induced apoptosis does not correlate to the levels of TRAIL-Rs at the plasma membrane, but rather to p53-mediated upregulation of Bax, favouring the mitochondrial amplification loop. Consistently, stronger caspase-9 and caspase-3 activation as well as PARP-cleavage was observed following TRAIL-R-triggering in HCT116 p53+/+ compared to HCT116 p53-/- cells. Interestingly, HCT116 p53+/+ cells showed also a more potent activation of non-canonical TRAIL-R-induced signal transduction pathways like JNK, p38 and ERK1/ERK2 than p53-/- cells. Likewise, these cells induced IL-8 expression in response to TRAIL, Mapatumumab or Lexatumumab significantly stronger than p53-/- cells. We obtained similar results in A549 cells with or without p53-knockdown and in the two isogenic colon cancer cell lines RKO p53+/+ and p53-/-. In both cellular systems, we could clearly demonstrate the potentiating effects of p53 on TRAIL-R-mediated IL-8 induction. In conclusion, we found that wild-type p53 increases TRAIL-R-mediated apoptosis but simultaneously augments non-apoptotic signaling.

Highlights

TRAIL (TNF-related apoptosis-inducing ligand) binds to four plasma membrane-bound receptors (TRAIL-R1-4)
Since TRAIL receptors are known transcriptional targets of p53, we first asked whether the p53 status might affect their expression in HCT116 cells
The results shown in S1 Fig clearly demonstrate the increased levels of TRAIL-R1 at the cell surface of HCT116 p53-/- when compared to HCT116 p53+/+ cells and show that the levels of TRAIL-R3 are slightly downregulated

Summary

Introduction

TRAIL (TNF-related apoptosis-inducing ligand) binds to four plasma membrane-bound receptors (TRAIL-R1-4). TRAIL-R1 and TRAIL-R2, are capable of inducing apoptosis via their intracellular death domain (DD) and are called death receptors. TRAIL-R3, anchored in the plasma membrane via glycosylphosphatidylinositol, contains neither a transmembrane nor a cytoplasmic domain. The cytoplasmic domain of TRAIL-R4 is able to induce several non-apoptotic signal transduction pathways but possesses a truncated, non-functional DD. Both TRAIL-R3 and TRAIL-R4 were proposed to negatively regulate TRAIL-induced apoptosis via direct interaction and/or ligand competition with the pro-apoptotic receptors TRAIL-R1/R2 [1–3]

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