Interaction between GRP78 and IGFBP-3 Affects Tumourigenesis and Prognosis in Breast Cancer Patients.

Hanna A Zielinska,Jeff M P Holly,Ahmad Alghamdi,Paul White,Carl S Daly,Claire M Perks,Amit Bahl,Sarah R Dean,Muhammed Sohail

doi:10.3390/cancers12123821

Abstract

Simple SummaryWe investigated the clinical significance of a recently identified association between insulin-like growth factor binding protein 3 (IGFBP-3), that plays a key role in breast cancer progression, and glucose-regulated protein 78 (GRP78). We report a direct correlation between the expression of GRP78 and IGFBP-3 in breast cancer cell lines and tumour sections. Kaplan–Meier survival plots revealed that patients with low GRP78 expression that are positive for IGFBP-3 had poorer survival rates than those with low IGFBP-3 levels. With breast cancer cells we showed that knock-down of GRP78 negated the entry of IGFBP-3 into the cells and this switched the action of IGFBP-3 from promoting to inhibiting cell death. Together, our data suggest that loss of GRP78 reduces IGFBP-3 entry into cells switching its actions to promote tumorigenesis and predicts a poor prognosis in breast cancer patients.Insulin-like growth factor binding protein 3 (IGFBP-3) plays a key role in breast cancer progression and was recently shown to bind to the chaperone protein glucose-regulated protein 78 (GRP78); however, the clinical significance of this association remains poorly investigated. Here we report a direct correlation between the expression of GRP78 and IGFBP-3 in breast cancer cell lines and tumour sections. Kaplan–Meier survival plots revealed that patients with low GRP78 expression that are positive for IGFBP-3 had poorer survival rates than those with low IGFBP-3 levels, and we observed a similar trend in the publicly available METABRIC gene expression database. With breast cancer cells, in vitro IGFBP-3 enhanced induced apoptosis, however when GRP78 expression was silenced the actions of IGFBP-3 were switched from increasing to inhibiting ceramide (C2)-induced cell death and promoted cell invasion. Using immunofluorescence and cell surface biotinylation, we showed that knock-down of GRP78 negated the entry of IGFBP-3 into the cells. Together, our clinical and experimental results suggest that loss of GRP78 reduces IGFBP-3 entry into cells switching its actions to promote tumorigenesis and predicts a poor prognosis in breast cancer patients.

Highlights

Breast cancer is the most common cancer in women globally and the second most prevalent cancer overall [1]
We examined the basal abundance of glucose-regulated protein 78 (GRP78) and Insulin-like growth factor binding protein 3 (IGFBP-3) in nonmalignant MCF-10A cells and breast cancer cell lines using Western blotting
Analysis of IGFBP-3 in this panel of cell lines revealed the highest levels of IGFBP-3 in the Hs578T cells, lower levels observed in MDA-MB-231 cells, with no detection of IGFBP-3 in the MCF-10A, MCF-7 and T47D cells (Figure 1(Ai, Aii))

Summary

Introduction

Breast cancer is the most common cancer in women globally and the second most prevalent cancer overall [1]. During the period from 2015 to 2017, Cancer Research UK reported 55,176 new cases of breast cancer with 11,399 deaths from the disease [2]. The insulin-like growth (IGF) axis is composed of two ligands, IGF-I and -II, receptors and six high affinity IGFBPs (16–) and there is strong evidence to suggest that its dysregulation is associated with the risk and progression of many cancers, including breast cancer [4]. Insulin-like growth factor binding protein-3 (IGFBP-3) is the main IGF binding protein in human serum, where it transports and controls the bioavailability and half-life of the IGFs. Insulin-like growth factor binding protein-3 (IGFBP-3) is the main IGF binding protein in human serum, where it transports and controls the bioavailability and half-life of the IGFs Whilst it is mainly synthesised in the liver, it is produced locally in both normal and tumour cells, including those of the breast [5]. IGFBP-3 can exert both positive and negative effects on cell function depending upon the cellular environment [6]

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