ADAM10 Releases a Soluble Form of the GPNMB/Osteoactivin Extracellular Domain with Angiogenic Properties

Goodman Cancer Research Centre, McGill University, Montreal, Quebec, Canada.
PLoS ONE (Impact Factor: 3.23). 08/2010; 5(8):e12093. DOI: 10.1371/journal.pone.0012093
Source: PubMed


Glycoprotein non-metastatic melanoma protein B (GPNMB)/Osteoactivin (OA) is a transmembrane protein expressed in approximately 40-75% of breast cancers. GPNMB/OA promotes the migration, invasion and metastasis of breast cancer cells; it is commonly expressed in basal/triple-negative breast tumors and is associated with shorter recurrence-free and overall survival times in patients with breast cancer. Thus, GPNMB/OA represents an attractive target for therapeutic intervention in breast cancer; however, little is known about the functions of GPNMB/OA within the primary tumor microenvironment.
We have employed mouse and human breast cancer cells to investigate the effects of GPNMB/OA on tumor growth and angiogenesis. GPNMB/OA-expressing tumors display elevated endothelial recruitment and reduced apoptosis when compared to vector control-derived tumors. Primary human breast cancers characterized by high vascular density also display elevated levels of GPNMB/OA when compared to those with low vascular density. Using immunoblot and ELISA assays, we demonstrate the GPNMB/OA ectodomain is shed from the surface of breast cancer cells. Transient siRNA-mediated knockdown studies of known sheddases identified ADAM10 as the protease responsible for GPNMB/OA processing. Finally, we demonstrate that the shed extracellular domain (ECD) of GPNMB/OA can promote endothelial migration in vitro.
GPNMB/OA expression promotes tumor growth, which is associated with enhanced endothelial recruitment. We identify ADAM10 as a sheddase capable of releasing the GPNMB/OA ectodomain from the surface of breast cancer cells, which induces endothelial cell migration. Thus, ectodomain shedding may serve as a novel mechanism by which GPNMB/OA promotes angiogenesis in breast cancer.

Download full-text


Available from: April Ann Nicole Rose,
  • Source
    • "GPNBM-OA stimulates recruitment of tumors-associated macrophages, which produce VEGF. ADAM-10 and ADAM 17 proteases release the extracellular domain of GPNMB-OA, which stimulates migration of endothelial cells, acting as a chemoattractant [23]. Progranulin stimulates proliferation of endothelial cells [26]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Triple negative breast cancer is a heterogeneous group of tumors, lacking the expression of estrogen, progesterone and HER-2 receptors. As frequency, it accounts about 15-20% of all breast cancers. Although in the last years there was a "boom" in publishing over this issue, multiple molecular classifications being elaborated, "the triple negative breast cancer odyssey " is still far away from ending, as the complicated molecular pathways of pathogenesis and drug resistance mechanisms remain yet insufficiently explored. The aim of this review is presentation of molecular signatures that could predict outcome and drug resistance in triple negative breast cancer.
    Breast (Edinburgh, Scotland) 09/2013; 22(6). DOI:10.1016/j.breast.2013.08.007 · 2.38 Impact Factor
  • Source
    • "GPNMB, initially termed glycoprotein non-metastatic gene B (NMB), was first cloned and described in 1995 as a protein highly expressed in a melanoma cell line with low metastatic potential.38 However, since this initial publication, elevated GPNMB expression is observed in numerous cancers and is often associated with the metastatic phenotype.27–34 GPNMB is also known as hematopoietic growth factor inducible, neurokinin-1 type (HGFIN),39 and is located on the small arm of chromosome 7 (7p15). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Molecularly targeted therapies are rapidly growing with respect to their clinical development and impact on cancer treatment due to their highly selective anti-tumor action. However, many aggressive cancers such as triple-negative breast cancer (TNBC) currently lack well-defined therapeutic targets against which such agents can be developed. The identification of tumor-associated antigens and the generation of antibody drug-conjugates represent an emerging area of intense interest and growth in the field of cancer therapeutics. Glycoprotein non-metastatic b (GPNMB) has recently been identified as a gene that is over-expressed in numerous cancers, including TNBC, and often correlates with the metastatic phenotype. In breast cancer, GPNMB expression in the tumor epithelium is associated with a reduction in disease-free and overall survival. Based on these findings, glembatumumab vedotin (CDX-011), an antibody-drug conjugate that selectively targets GPNMB, is currently being investigated in clinical trials for patients with metastatic breast cancer and unresectable melanoma. This review discusses the physiological and potential pathological roles of GPNMB in normal and cancer tissues, respectively, and details the clinical advances and challenges in targeting GPNMB-expressing malignancies.
    OncoTargets and Therapy 07/2013; 6:839-52. DOI:10.2147/OTT.S44906 · 2.31 Impact Factor
  • Source
    • "ADAMs are also important for the shedding of proteolytic enzymes from the plasma membrane [20, 70, 71]. ADAM10 itself is released from the cell surface through cleavage by ADAM9 and ADAM15, indicating that ADAM10 has dual functions in the cell [72]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: The in vivo roles of meprin metalloproteases in pathophysiological conditions remain elusive. Substrates define protease roles. Therefore, to identify natural substrates for human meprin α and β we employed TAILS (terminal amine isotopic labeling of substrates), a proteomics approach that enriches for N-terminal peptides of proteins and cleavage fragments. Of the 151 new extracellular substrates we identified, it was notable that ADAM10 (a disintegrin and metalloprotease domain-containing protein 10)—the constitutive α-secretase—is activated by meprin β through cleavage of the propeptide. To validate this cleavage event, we expressed recombinant proADAM10 and after preincubation with meprin β, this resulted in significantly elevated ADAM10 activity. Cellular expression in murine primary fibroblasts confirmed activation. Other novel substrates including extracellular matrix proteins, growth factors and inhibitors were validated by western analyses and enzyme activity assays with Edman sequencing confirming the exact cleavage sites identified by TAILS. Cleavages in vivo were confirmed by comparing wild-type and meprin−/− mice. Our finding of cystatin C, elafin and fetuin-A as substrates and natural inhibitors for meprins reveal new mechanisms in the regulation of protease activity important for understanding pathophysiological processes. Electronic supplementary material The online version of this article (doi:10.1007/s00018-012-1106-2) contains supplementary material, which is available to authorized users.
    Cellular and Molecular Life Sciences CMLS 09/2012; 70(2). DOI:10.1007/s00018-012-1106-2 · 5.81 Impact Factor
Show more