Citations

Abstract Zebrafish ( Danio rerio ) is a popular vertebrate model organism largely deployed using outbred laboratory animals. The nonisogenic nature of the zebrafish as a model system offers the opportunity to understand natural variations and their effect in modulating phenotype. In an effort to better characterize the range of natural variation in this model system and to complement the zebrafish reference genome project, the whole genome sequence of a wild zebrafish at 39-fold genome coverage was determined. Comparative analysis with the zebrafish reference genome revealed approximately 5.2 million single nucleotide variations and over 1.6 million insertion–deletion variations. This dataset thus represents a new catalog of genetic variations in the zebrafish genome. Further analysis revealed selective enrichment for variations in genes involved in immune function and response to the environment, suggesting genome-level adaptations to environmental niches. We also show that human disease gene orthologs in the sequenced wild zebrafish genome show a lower ratio of nonsynonymous to synonymous single nucleotide variations.

Hypophosphatemia with osteomalacia may be due to a neoplasm that produces fibroblast growth factor 23 (FGF-23), which inhibits phosphate reabsorption in the kidneys. Most of these tumors occur in bone or soft tissue and occasionally in the head, although intracranial occurrence is very rare. This report describes a tumor that caused hypophosphatemia and osteomalacia and was located entirely in the right anterior cranial fossa. Radiologically, the tumor resembled a meningioma; histologically, it was a low-grade phosphaturic mesenchymal tumor, mixed connective tissue variant (PMTMCT). After gross-total resection, the patient's symptoms abated and laboratory values normalized. The authors also studied another PMTMCT initially diagnosed as a hemangiopericytoma that involved the left anterior cranial fossa and ethmoid sinus, and reviewed reports of 6 other intracranial tumors that induced osteomalacia, 3 entirely in the anterior cranial fossa, 2 involving the anterior cranial fossa and ethmoid sinus, and 1 in the cavernous sinus. In older children or adults who have hypophosphatemia with osteomalacia and no personal or family history of metabolic, renal, or malabsorptive disease, a neoplasm should be suspected and an imaging workup that includes the brain is warranted, with particular attention to the anterior cranial fossa. Additionally, because there are some overlapping histological features between PMTMCTs and hemangiopericytomas, it may be helpful to assess tumoral FGF-23 expression by reverse transcriptase polymerase chain reaction or immunohistochemical analysis in patients with oncogenic osteomalacia from an intracranial tumor diagnosed as, or resembling, hemangiopericytoma.

Abstract PRSS3/mesotrypsin is an atypical isoform of trypsin that has been associated with breast, lung, and pancreatic cancer cell malignancy. In analyses of open source transcriptional microarray data, we find that PRSS3 expression is upregulated in metastatic prostate cancer tissue, and that expression of PRSS3 in primary prostate tumors is prognostic of systemic progression following prostatectomy. Using a mouse orthotopic model with bioluminescent imaging, we show that PRSS3/mesotrypsin is critical for prostate cancer metastasis. Silencing of PRSS3 inhibits anchorage-independent growth of prostate cancer cells in soft agar assays, and suppresses invasiveness in Matrigel transwell assays and three-dimensional (3D) cell culture models. We further show that treatment with recombinant mesotrypsin directly promotes an invasive cellular phenotype in prostate cancer cells and find that these effects are specific and require the proteolytic activity of mesotrypsin, because neither cationic trypsin nor a mesotrypsin mutant lacking activity can drive the invasive phenotype. Finally, we show that a newly developed, potent inhibitor of mesotrypsin activity can suppress prostate cancer cell invasion to a similar extent as PRSS3 gene silencing. This study defines mesotrypsin as an important mediator of prostate cancer progression and metastasis, and suggests that inhibition of mesotrypsin activity may provide a novel modality for prostate cancer treatment. Mol Cancer Res; 10(12); 1555–66. ©2012 AACR.

Abstract Diffuse idiopathic skeletal hyperostosis (DISH) is a noninflammatory spondyloarthropathy, characterized by ectopic calcification of spinal tissues. Symptoms include spine pain and stiffness, and in severe cases dysphagia and spinal cord compression. The etiology of DISH is unknown and there are no specific treatments. Recent studies have suggested a role for purine metabolism in the regulation of biomineralization. Equilibrative nucleoside transporter 1 (ENT1) transfers hydrophilic nucleosides, such as adenosine, across the plasma membrane. In mice lacking ENT1, we observed the development of calcified lesions resembling DISH. By 12 months of age, ENT1–/– mice exhibited signs of spine stiffness, hind limb dysfunction, and paralysis. Micro–computed tomography (µCT) revealed ectopic mineralization of paraspinal tissues in the cervical-thoracic region at 2 months of age, which extended to the lumbar and caudal regions with advancing age. Energy-dispersive X-ray microanalysis of lesions revealed a high content of calcium and phosphorus with a ratio similar to that of cortical bone. At 12 months of age, histological examination of ENT1–/– mice revealed large, irregular accumulations of eosinophilic material in paraspinal ligaments and entheses, intervertebral discs, and sternocostal articulations. There was no evidence of mineralization in appendicular joints or blood vessels, indicating specificity for the axial skeleton. Plasma adenosine levels were significantly greater in ENT1–/– mice than in wild-type, consistent with loss of ENT1—a primary adenosine uptake pathway. There was a significant reduction in the expression of Enpp1, Ank, and Alpl in intervertebral discs from ENT1–/– mice compared to wild-type mice. Elevated plasma levels of inorganic pyrophosphate in ENT1–/– mice indicated generalized disruption of pyrophosphate homeostasis. This is the first report of a role for ENT1 in regulating the calcification of soft tissues. Moreover, ENT1–/– mice may be a useful model for investigating pathogenesis and evaluating therapeutics for the prevention of mineralization in DISH and related disorders. © 2013 American Society for Bone and Mineral Research.

Breast tumor development is regulated in part by cues from the local microenvironment, including interactions with neighboring nontumor cells as well as the ECM. Studies using homogeneous populations of breast cancer cell lines cultured in 3D ECM have shown that increased ECM stiffness stimulates tumor cell invasion. However, at early stages of breast cancer development, malignant cells are surrounded by normal epithelial cells, which have been shown to exert a tumor-suppressive effect on cocultured cancer cells. Here we explored how the biophysical characteristics of the host microenvironment affect the proliferative and invasive tumor phenotype of the earliest stages of tumor development, by using a 3D microfabrication-based approach to engineer ducts composed of normal mammary epithelial cells that contained a single tumor cell. We found that the phenotype of the tumor cell was dictated by its position in the duct: proliferation and invasion were enhanced at the ends and blocked when the tumor cell was located elsewhere within the tissue. Regions of invasion correlated with high endogenous mechanical stress, as shown by finite element modeling and bead displacement experiments, and modulating the contractility of the host epithelium controlled the subsequent invasion of tumor cells. Combining microcomputed tomographic analysis with finite element modeling suggested that predicted regions of high mechanical stress correspond to regions of tumor formation in vivo. This work suggests that the mechanical tone of nontumorigenic host epithelium directs the phenotype of tumor cells and provides additional insight into the instructive role of the mechanical tumor microenvironment.

Abstract Benign breast disease (BBD) is an established risk factor for breast cancer among Caucasian women but less is known about BBD in African American women. As African American women suffer from disproportionate mortality due to breast cancer, special focus on pathologic characteristics that may influence disease risk is warranted. Benign breast biopsies from African American women were identified by the University Pathology Group (Detroit, MI). African American women of ages 20 to 84 years, who underwent a breast biopsy from 1997 to 2000, were eligible for the study. Subsequent breast cancers were identified through a linkage with the Detroit Surveillance Epidemiology and End Results (SEER) program. The first biopsy was reviewed by the pathologist, and lesions were classified following Dupont and Page criteria along with involution and other histologic features. Logistic regression was used to estimate the risk of developing a subsequent breast cancer with the histologic characteristics of BBD. A total of 1,406 BBD biopsies from African American women were included in this study with a median follow-up of 10.1 years. The majority (68%) showed nonproliferative disease, 29% had proliferative disease without atypia, and 3% had proliferative disease with atypia. Subsequent incident breast cancers occurred in 55 women (3.9%). Women whose biopsies showed proliferative disease with atypia were more than three-fold more likely to develop breast cancer as compared with women who had nonproliferative disease [relative risk (RR) 3.29, 95% confidence interval (CI) 1.21–8.93]. Better characterization of the risk of breast cancer among women with BBD, considering both ethnicity and detailed molecular findings, can lead to better surveillance, earlier diagnosis, and potentially improved survival. Cancer Prev Res; 5(12); 1375–80. ©2012 AACR.