Pellino-1 promotes lung carcinogenesis via the stabilization of Slug and Snail through K63-mediated polyubiquitination

Yoon Kyung Jeon,Geun-Hyoung Ha,Jaemoon Koh,Chung Kwon Kim,Kyung Rim Hwang,Hye-Young Park,Chang-Woo Lee,Doo Hyun Chung

doi:10.1038/cdd.2016.143

Abstract

Pellino-1 is an E3 ubiquitin ligase acting as a critical mediator for a variety of immune receptor signaling pathways, including Toll-like receptors, interleukin-1 receptor and T-cell receptors. We recently showed that the Pellino-1-transgenic (Tg) mice developed multiple tumors with different subtypes in hematolymphoid and solid organs. However, the molecular mechanism underlying the oncogenic role of Pellino-1 in solid tumors remains unknown. Pellino-1-Tg mice developed adenocarcinoma in the lungs, and Pellino-1 expression was higher in human lung adenocarcinoma cell lines compared with non-neoplastic bronchial epithelial cell lines. Pellino-1 overexpression increased the cell proliferation, survival, colony formation, invasion and migration of lung adenocarcinoma cells, whereas Pellino-1 knock-down showed the opposite effect. Pellino-1 overexpression activated PI3K/Akt and ERK signaling pathways and elicited an epithelial–mesenchymal transition (EMT) phenotype of lung adenocarcinoma cells. Pellino-1-mediated EMT was demonstrated through morphology, the upregulation of Vimentin, Slug and Snail expression and the downregulation of E-cadherin and β-catenin expression. Notably, Pellino-1 had a direct effect on the overexpression of Snail and Slug through Lys63-mediated polyubiquitination and the subsequent stabilization of these proteins. Pellino-1 expression level was significantly correlated with Snail and Slug expression in human lung adenocarcinoma tissues, and lung tumors from Pellino-1-Tg mice showed Snail and Slug overexpression. The Pellino-1-mediated increase in the migration of lung adenocarcinoma cells was mediated by Snail and Slug expression. Taken together, these results show that Pellino-1 contributes to lung tumorigenesis by inducing overexpression of Snail and Slug and promoting EMT. Pellino-1 might be a potential therapeutic target for lung cancer.

Highlights

Epithelial–mesenchymal transition (EMT) has important roles in the formation of the body plan and in the differentiation of various tissues and organs.[1,2] EMT has a critical role in the carcinogenic process through various molecular pathways.[1,3,4] EMT promotes tumor cell invasion and metastasis, leading to the generation of cancer cells with stem cell-like characteristics and resistance to chemotherapy.[4,5]
Pellino-1 was variably expressed in human lung cancer tissues (Figure 1c, middle) with the highest frequency in adenocarcinoma (Figure 1c, lower) among non-small cell lung cancer (NSCLC)
Through in vitro and in vivo models using multiple lung cancer cell lines and xenograft and validation with human lung cancer tissues, we demonstrated that Pellino-1 has an oncogenic role in lung cancer through the stabilization of Snail and Slug via K63-mediated polyubiquitination, thereby promoting the EMT phenomenon

Summary

Introduction

Epithelial–mesenchymal transition (EMT) has important roles in the formation of the body plan and in the differentiation of various tissues and organs.[1,2] EMT has a critical role in the carcinogenic process through various molecular pathways.[1,3,4] EMT promotes tumor cell invasion and metastasis, leading to the generation of cancer cells with stem cell-like characteristics and resistance to chemotherapy.[4,5]. The loss of expression of the epithelial marker E-cadherin is a hallmark of EMT, associated with the upregulation of E-cadherin transcriptional repressors, such as Snail, Slug, Twist, ZEB1 and ZEB2.6–9 In addition, EMT is regulated through various signaling networks including ERK, MAPK, PI3K/Akt, TGF-β, Wnt/β-catenin and Notch pathways.[2,4,10,11,12]. Transcriptional repressors of E-cadherin are upregulated in lung cancer, associated with tumor progression and poor prognosis of patients.[17,18,19,20]. The Pellino family comprises three evolutionally conserved members (Pellino-1/2/3) that possess Ring-like motifs, a defining feature of the RING class of E3 ubiquitin ligases.[21]

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Results

Conclusion