ANGPTL4 overexpression inhibits tumor cell adhesion and migration and predicts favorable prognosis of triple-negative breast cancer

Abstract

Background: Triple-negative breast cancer (TNBC) patients have relatively poor clinical outcomes. A marker predicting the prognosis of patients with TNBC could help guide treatment. Extensive evidence demonstrates that angiopoietin-like 4 (ANGPTL4) is involved in the regulation of cancer growth, metastasis and angiogenesis. Therefore, its role in TNBC is of interest.

Methods: We tested the ANGPTL4 expression level in tumor tissues by immunohistochemistry (IHC) and detected its association with the clinical features of TNBC patients. Next, the effects and mechanisms of ANGPTL4 on TNBC cell migration and adhesion were investigated.

Results: We found that ANGPTL4 overexpression was associated with favorable outcomes in TNBC patients. ANGPTL4 upregulation inhibited cell adhesion, migration and invasion in vitro. Further analyses demonstrated that the possible mechanism might involve suppression of TNBC progression by interacting with extracellular matrix-related genes.

Conclusions: The present findings demonstrated that enhancement of ANGPTL4 expression might inversely correlate with TNBC progression. ANGPTL4 is a promising marker of TNBC and should be evaluated in further studies.

Trial registration: Retrospectively registered.

Keywords: ANGPTL4; Adhesion; Migration; Prognosis; Triple negative breast Cancer.

Fig. 1

The role of ANGPTL4 expression in TNBC and its prognostic value. a The ANGPTL4 expression level in TNBC samples. Protein staining was mainly observed in the cytoplasm (100× and 200×). b Stromal cells express stronger positivity than TNBC tumor cells. c The expression status of ANGPTL4 in adipocytes and epithelial cells was showed, ANGPTL4 protein is overexpressed in adipocytes (solid arrow) and epithelial cells (hollow arrow). d The ROC curve for the scores of ANGPTL4 expression was plotted to select the appropriate cut-off score. The area under the curve was 0.634 (p = 0.007). e Kaplan–Meier survival curves of 161 patients with TNBC. The curves revealed that high ANGPTL4 expression predicted longer OS and DFS (IBM SPSS 22.0 statistical software package)

Fig. 2

ANGPTL4 overexpression inhibits cell migration, invasion and adhesion in invasive breast cancer cell lines. a The expression of ANGPTL4 in luminal BC cell lines such as SKRB3 and MDA-MB-453 is higher than that in basal-like BC cell lines such as BT549 and MDA-MB-231. b The efficiency of transfection was confirmed by Western blots. Stable ANGPTL4-overexpressing cells (abbreviated BT549 and 231 ANGPTL4 OE) exhibited weaker wound healing (c), Matrigel invasion (d) and attachment abilities than the negative control (abbreviated NC) and empty vector cells (Graghpad Prism statistical software package, version 5.01, The Student’s t-test was used, *p < 0.05)

Fig. 3

ANGPTL4 overexpression decreases the mRNA levels of ECM-related genes. a Next-generation RNA sequencing revealed that genes related to adherens junctions, blood vessel morphogenesis, extracellular matrix and wound healing were most affected by ANGPTL4 overexpression. b Real-time quantitative PCR confirmed that ten genes were downregulated in the 231 ANGPTL4 OE group compared with the control group. These results suggest that ANGPTL4 overexpression might affect TNBC progression by inhibiting ECM-related genes (Graghpad Prism statistical software package, version 5.01, *p < 0.05)