Tp53 Mutation Inhibits Ubiquitination and Degradation of WISP1 via Down-Regulation of Siah1 in Pancreatic Carcinogenesis

Abstract

Wnt1 inducible signaling pathway protein-1 (WISP1) may play an important role in promoting carcinogenesis. However, the biological function and underlying mechanism of WISP1 in pancreatic carcinogenesis still remains enigmatic. In this study, immunochemistry staining showed that protein levels of WISP1 were more significantly upregulated in pancreatic ductal adenocarcinoma (PDAC) tissues with Tp53 mutation than in PDAC tissues with Tp53 wild-type. In addition, a significant correlation was observed between increased malignant phenotype of tumors from well-differentiated adenocarcinoma tissues to moderately- or poorly-differentiated adenocarcinoma tissues shifting from cytoplasmic expression to nuclear accumulation of WISP1. Interestingly, WISP1 expression was correlated with the poor prognosis in PDAC patients with Tp53 mutation. Also, the biological function analysis showed that WISP1 may act as a potential oncogene in PDAC cells. In addition, immunofluorescence analysis showed that Tp53 mutation promoted WISP1 expression in PanIN and PDAC cells, while Siah E3 Ubiquitin Protein Ligase 1 (Siah1) inhibited WISP1 expression in PDAC cells. Moreover, through immunoprecipitation, immunoblotting analysis, in vitro binding assay, and ubiquitination assay, we found that Tp53 mutation inhibited ubiquitination and degradation of Siah1-dependent WISP1. Therefore, Tp53 mutation-Siah1-WISP1 is a new signaling pathway, playing an important role in pancreatic carcinogenesis.

Loss of Wasl improves pancreatic cancer outcome

“…YAP1 is involved in several signaling pathways, where it plays a different role depending on the upstream members (62). WIP is also involved in the regulation of endocytosis (63) and participates in several cellular processes, some of which are relevant in cancer and which may be dependent on different oncogenic stimuli (17,64,65). We showed that CKP-N ΔPanc tumors displayed a small amount of membranous WIP, which probably resulted in the increased rate of endocytosis that we observed in these tumors.…”

Host cell factors stimulate HIV-1 transcription by antagonizing substrate-binding function of Siah1 ubiquitin ligase to stabilize transcription elongation factor ELL2

“…Past studies have identified a number of mechanisms that control Siah1/2 at both the transcriptional and post-translational levels. For example, the expression of Siah1/2 can be modulated through transcriptional activation by certain sequence-specific transcription factors ( 28–33 ), gene amplification of the Siah2 genomic loci ( 34 ), as well as specific miRNAs ( 35–40 ). In addition, the activity of Siah1/2 can often be controlled by phosphorylation, which in some cases affects the subcellular localization of the E3s and in others their interactions of with the substrates ( 41–43 ).…”

Exosomes with low miR-34c-3p expression promote invasion and migration of non-small cell lung cancer by upregulating integrin α2β1

“…After that, the cell lysates were incubated with Protein G Dynabeads at 4°C for 3 h. After two washes with IP buffer, the proteins on the Dynabeads were eluted for 5 min by boiling at 95°C in SDS sample buffer, and then they were separated by SDS-PAGE for subsequent Western blotting. 41 Immunohistochemistry Paraffin-embedded tumor tissues were serially sectioned, deparaffinized in xylene and rehydrated with different concentrations of alcohol. Then, endogenous peroxidase was blocked by 3% v/v H 2 O 2 .…”