MiR-193b regulates breast cancer cell migration and vasculogenic mimicry by targeting dimethylarginine dimethylaminohydrolase 1

Abstract

Dimethylarginine dimethylaminohydrolase 1 (DDAH1) is responsible for metabolism of an endogenous inhibitor of nitric oxide synthase (NOS), asymmetric dimethylarginine (ADMA), which plays a key role in modulating angiogenesis. In addition to angiogenesis, tumours can establish a vascular network by forming vessel-like structures from tumour cells; a process termed vasculogenic mimicry (VM). Here, we identified over-expression of DDAH1 in aggressive MDA-MB-231, MDA-MB-453 and BT549 breast cancer cell lines when compared to normal mammary epithelial cells. DDAH1 expression was inversely correlated with the microRNA miR-193b. In DDAH1+ MDA-MB-231 cells, ectopic expression of miR-193b reduced DDAH1 expression and the conversion of ADMA to citrulline. In DDAH1− MCF7 cells, inhibition of miR-193b elevated DDAH1 expression. Luciferase reporter assays demonstrated DDAH1 as a direct target of miR-193b. MDA-MB-231 cells organised into tube structures in an in vitro assay of VM, which was significantly inhibited by DDAH1 knockdown or miR-193b expression. Mechanistically, we found miR-193b regulates cell proliferation and migration of MDA-MB-231 cells, whilst DDAH1 knockdown inhibited cell migration. These studies represent the first evidence for DDAH1 expression, regulation and function in breast cancer cells, and highlights that targeting DDAH1 expression and/or enzymatic activity may be a valid option in the treatment of aggressive breast cancers.

Inhibition of Dimethylarginine Dimethylaminohydrolase (DDAH) Enzymes as an Emerging Therapeutic Strategy to Target Angiogenesis and Vasculogenic Mimicry in Cancer

“…It is important to note that immunofluorescence analysis of tumor tissue samples confirmed expression of DDAH1 localized to hepatocytes, and absent from neighboring endothelial cells of vascular structures (188). We have also recently published evidence for a novel role of DDAH1 in breast cancer, particularly in the more aggressive and invasive triple negative breast cancer (TNBC) molecular subtype (187). In this study we demonstrated high expression of functional DDAH1 enzyme in TNBC cells relative to normal mammary epithelial cells.…”

“…Studies to date have demonstrated an increase in DDAH1 protein expression in human glioma, meningioma, prostate cancer, and hepatocellular carcinoma, primarily by means of large-scale proteomic analysis. An upregulation of DDAH1 protein has also been observed in cohorts of melanoma and breast cancer cell lines, relative to normal melanocyte, and mammary epithelial cells, respectively (183,187). Aside from the identification that DDAH1 expression is significantly altered in these cancers, only a handful of these studies undertook further analysis into the specific role and function of DDAH1 within each cancer context.…”

Vasculogenic mimicry in carcinogenesis and clinical applications

“…Furthermore, IL-6-induced adhesion of monocytes to ECs and VM formation were suppressed by endothelial miR-125a/let-7e [96]. miR-193b regulates breast cancer cells (MDA-MB-231 cells) migration and VM formation via targeting dimethylarginine dimethylaminohydrolase 1 (DDAH1) [97] (Table 1). MALAT1, as a well-characterized lncRNA molecule, plays an important role in cancer cell invasion and metastasis and VM formation.…”

An Overview of Vasculogenic Mimicry in Breast Cancer

“…The enzyme DDAH1 (dimethylarginine dimethylaminohydrolase-1) has also been associated with the formation of VM: inhibition of DDAH1 in MDA-MB-231 cells prevents the formation of VM. Interestingly, miR-193b decreases the levels of DDAH1 and, therefore, inhibits the formation of VM (41,42). Other miRNAs regulate VM in breast cancer.…”