Endosulfatases SULF1 and SULF2 limit Chlamydia muridarum infection.

The first step in attachment of Chlamydia to host cells is thought to involve reversible binding to host heparan sulfate proteoglycans (HSPGs), polymers of variably sulfated repeating disaccharide units coupled to diverse protein backbones. However, the key determinants of HSPG structure that are involved in Chlamydia binding are incompletely defined. A previous genome-wide Drosophila RNAi screen suggested that the level of HSPG 6-O sulfation rather than the identity of the proteoglycan backbone maybe a critical determinant for binding. Here, we tested in mammalian cells whether SULF1 or SULF2, human endosulfatases, which remove 6-O sulfates from HSPGs, modulate Chlamydia infection. Ectopic expression of SULF1 or SULF2 in HeLa cells, which decreases cell surface HSPG sulfation, diminished C. muridarum binding and decreased vacuole formation. ShRNA depletion of endogenous SULF2 in a cell line that primarily expresses SULF2 augmented binding and increased vacuole formation. C. muridarum infection of diverse cell lines resulted indownregulation of SULF2 mRNA. In a murine model of acute pneumonia, mice genetically deficient in both endosulfatases or in SULF2 alone demonstrated increased susceptibility to C. muridarum lung infection. Collectively, these studies demonstrate that the level of HSPG 6-O sulfation is a critical determinant of C. muridarum infection in vivo and that 6-O endosulfatases are previously unappreciated modulators of microbial pathogenesis.

EMMPRIN regulates the canonical Wnt/beta-catenin signaling pathway, a potential role in accelerating lung tumorigenesis.

Advances in the field of tumor biology have identified that tumor cells co-opt developmental signaling pathways of embryonic stem cells and thus gain the ability to proliferate, differentiate and alter cell-cell interactions. One such pathway is the Wnt/beta-catenin signaling pathway. High levels of EMMPRIN expression have been shown to correlate with poor prognosis and metastasis in a broad range of tumors. Although a variety of functions are attributed to EMMPRIN in tumorigenesis, the specific mechanism(s) through which it can exert its effects have not been elucidated, until now. In this study, we identify EMMPRIN as a novel regulator of the canonical Wnt/beta-catenin signaling pathway in lung cancer. Increasing EMMPRIN expression levels in lung cancer epithelial cells upregulated the beta-catenin signaling pathway and silencing EMMPRIN inhibited beta-catenin signaling, cell migration, proliferation, anchorage-independent growth and tumor growth in a mouse tumor xenograft model. These results provide a compelling rationale for targeting EMMPRIN for anticancer therapies. Understanding the molecular mechanisms driving EMMPRIN-induced lung tumorigenesis will provide enormous benefits in developing new therapeutic treatments for this and other forms of cancer.

Sulf-2, a heparan sulfate endosulfatase, promotes human lung carcinogenesis.

Heparan sulfate (HS) proteoglycans (HSPGs) bind to multiple growth factors/morphogens and regulate their signaling. 6-O-sulfation (6S) of glucosamine within HS chains is critical for many of these ligand interactions. Sulf-1 and Sulf-2, which are extracellular neutral-pH sulfatases, provide a novel post-synthetic mechanism for regulation of HSPG function by removing 6S from intact HS chains. The Sulfs can thereby modulate several signaling pathways, including the promotion of Wnt signaling. We found induction of SULF2 transcripts and Sulf-2 protein in human lung adenocarcinoma and squamous cell carcinoma, the two major classes of non-small-cell lung carcinomas (NSCLCs). We confirmed widespread Sulf-2 protein expression in tumor cells of 10/10 surgical specimens of human lung squamous carcinomas. We studied five Sulf-2(+) NSCLC cell lines, including two, which were derived by cigarette-smoke transformation of bronchial epithelial cells. shRNA-mediated Sulf-2 knockdown in these lines caused an increase in 6S on their cell surface and in parallel reversed their transformed phenotype in vitro, eliminated autocrine Wnt signaling and strongly blunted xenograft tumor formation in nude mice. Conversely, forced Sulf-2 expression in non-malignant bronchial epithelial cells produced a partially transformed phenotype. Our findings support an essential role for Sulf-2 in lung cancer, the leading cancer killer.