Extracellular matrix 1 (ECM1) regulates the actin cytoskeletal architecture of aggressive breast cancer cells in part via S100A4 and Rho-family GTPases

Abstract

ECM1 overexpression is an independent predictor of poor prognosis in primary breast carcinomas, however the mechanisms by which ECM1 affects tumor progression have not been completely elucidated. ECM1 was silenced in the triple-negative breast cancer cell lines Hs578T and MDAMB231 using siRNA and the cells were evaluated for changes in morphology, migration, invasion and adhesion. Actin cytoskeleton alterations were evaluated by fluorescent staining and levels of activated Rho GTPases by pull down assays. ECM1 downregulation led to significantly diminished cell migration (p=0.0005 for Hs578T and p=0.02 for MDAMB231) and cell adhesion (p<0.001 for Hs578T and p=0.01 for MDAMB231). Cell invasion (matrigel) was reduced only in the Hs578T cells (p<0.01). Silencing decreased the expression of the prometastatic molecules S100A4 and TGFβR2 in both cell lines and CD44 in Hs578T cells. ECM1–silenced cells also exhibited alterations in cell shape and showed bundles of F-actin across the cell (stress fibers) whereas NT-siRNA treated cells showed peripheral membrane ruffling. Downregulation of ECM1 was also associated with an increased F/G actin ratio, when compared to the cells transfected with NT siRNA (p < 0.001 for Hs578T and p<0.00035 for MDAMB231) and a concomitant decline of activated Rho A in the Hs578T cells. Re-expression of S100A4 in ECM1-silenced cells rescued the phenotype in the Hs578T cells but not the MDAMB231 cells. We conclude that ECM1 is a key player in the metastatic process and regulates the actin cytoskeletal architecture of aggressive breast cancer cells at least in part via alterations in S100A4 and Rho A.

S100A4 in cancer progression and metastasis: A systematic review

“…In cells without Rhotekin or S100A4 expressions, RhoA activation and non-oligomeric myosin did not co-accumulate nor promote stress fiber formation [ 63 ]. S100A4 affected the balance between RhoA-mediated actomyosin contractility and actin polymerization to enhance cell mobility [ 64 ]. Recently, Lee et al reported that reduction of S100A4 levels affected cell morphology, actin cytoskeleton, and Rho GTPases, which in turn altered the prognosis in breast cancer [ 65 ].…”

Tumor‐derived exosomal proteins as diagnostic biomarkers in non‐small cell lung cancer

“…Alpha-2-HS-glycoprotein shows a positive association with the risk of colorectal cancer, 17 whereas ECM1 is identified as an indicator of increased metastasis and poor prognosis. 18 In the current study, we proposed sev- of serum CEA was higher in patients with lung cancer than those with benign lung diseases; however, the specificity of CEA is low, with 61.9% of NSCLC patients detected with abnormal CEA serum levels. [24][25][26] As a biomarker, CEA is more accurate in latestage disease than in early stage disease.…”

“…Furthermore, an in‐depth analysis of the mass spectrometry data revealed the differential expression of proteins AHSG and ECM1; these were selected to determine the difference between NSCLC patients and healthy donors. Alpha‐2‐HS‐glycoprotein shows a positive association with the risk of colorectal cancer, whereas ECM1 is identified as an indicator of increased metastasis and poor prognosis . In the current study, we proposed several lines of evidence to validate that AHSG and ECM1 served as potential biomarkers for NSCLC.…”

“…Alpha‐2‐HS‐glycoprotein can promote breast cancer progression and Lewis lung carcinoma tumorigenesis; it also positively associated with the risk of colorectal cancer . Extracellular matrix protein 1 is found to promote progression and invasion in most cancers and identified as an indicator of increased metastasis and poor prognosis . Thus, the detection of their expression levels in exosomes separated from the serum of NSCLC patients and healthy individuals prompted further exploration of the value of exosomal AHSG and ECM1 in cancer diagnosis.…”

Depletion of S100A4+ stromal cells does not prevent HCC development but reduces the stem cell-like phenotype of the tumors

“… 6 Expression of S100A4 is associated with poor prognosis in several human cancers including breast and colorectal cancers. 7 , 8 S100A4 also has a role in promoting metastatis 9 , 10 , 11 and in epithelial-mesenchymal transition in colorectal cancer 12 , 13 and ovarian cancer. 14 In HCC, abnormal expression of S100A4 correlates with poor prognosis.…”