MIR21-induced loss of junctional adhesion molecule A promotes activation of oncogenic pathways, progression and metastasis in colorectal cancer

Andrea Lampis,Chiara Braconi,Joanne Edwards,Georgios Vlachogiannis,Pierluigi Gasparini,Gabriela Kramer-Marek,Paul G Horgan,Luigi Terracciano,Luciano Cascione,Claudio Murgia,Carlos D Martins,Elisa Fontana,Carlo M Croce,Jens C Hahne,Owen J Sansom,Nicola Valeri,Matteo Fassan,Somaieh Hedayat

doi:10.1038/s41418-021-00820-0

Abstract

Junctional adhesion molecules (JAMs) play a critical role in cell permeability, polarity and migration. JAM-A, a key protein of the JAM family, is altered in a number of conditions including cancer; however, consequences of JAM-A dysregulation on carcinogenesis appear to be tissue dependent and organ dependent with significant implications for the use of JAM-A as a biomarker or therapeutic target. Here, we test the expression and prognostic role of JAM-A downregulation in primary and metastatic colorectal cancer (CRC) (n = 947). We show that JAM-A downregulation is observed in ~60% of CRC and correlates with poor outcome in four cohorts of stages II and III CRC (n = 1098). Using JAM-A knockdown, re-expression and rescue experiments in cell line monolayers, 3D spheroids, patient-derived organoids and xenotransplants, we demonstrate that JAM-A silencing promotes proliferation and migration in 2D and 3D cell models and increases tumour volume and metastases in vivo. Using gene-expression and proteomic analyses, we show that JAM-A downregulation results in the activation of ERK, AKT and ROCK pathways and leads to decreased bone morphogenetic protein 7 expression. We identify MIR21 upregulation as the cause of JAM-A downregulation and show that JAM-A rescue mitigates the effects of MIR21 overexpression on cancer phenotype. Our results identify a novel molecular loop involving MIR21 dysregulation, JAM-A silencing and activation of multiple oncogenic pathways in promoting invasiveness and metastasis in CRC.

Highlights

Junctional adhesion molecule A (JAM-A) is a critical component for the maintenance of epithelial cell homoeostasis and preservation of barrier function in the large intestine
JAMA staining was negative in 7.1% of primary tumours and in 14.3% of paired metastases, while a patchy cytoplasmic expression pattern was observed in 48.2% of primary tumours and in 44.6% of paired metastases (Fig. 1B)
While exploring whether the reduction in Junctional adhesion molecules (JAMs)-A expression observed in colorectal cancer (CRC) might be due to MiRNA-mediated silencing, we identified a putative binding site for MIR21, one of the most significantly upregulated MiRNAs in CRC [38], in the JAM-A 3′-untraslated region (UTR) (Fig. 5A)

Summary

Introduction

Junctional adhesion molecule A (JAM-A) is a critical component for the maintenance of epithelial cell homoeostasis and preservation of barrier function in the large intestine. Aberrant JAMA expression has been linked to enhanced colon epithelial permeability, increased inflammation due to leucocyte transmigration and loss of barrier function in pre-clinical models and patients with inflammatory bowel disease [1]. Pre-clinical data suggest that Apc loss induces JAM-A downregulation in the intestine of genetically engineered mouse models (GEMMs) eliciting loss of barrier function, loss of polarity and inflammation [10]. No data are currently available on JAM-A expression in early and metastatic colorectal cancer (CRC). We tested prognostic and functional implications of JAM-A dysregulation, in early and metastatic CRC

Methods

Results

Conclusion