The EXT2 multiple exostoses gene defines a family of putative tumour suppressor genes

Hereditary multiple exostoses (EXT) is an autosomal dominant condition characterized by short stature and the development of bony protuberances at the ends of all the long bones. Three genetic locl have been identified by genetic linkage analysis at chromosomes 8q24.1, 11p11-13 and 19p. The EXT1 gene on chromosome 8 was recently identified and characterized. Here, we report the isolation and characterization of the EXT2 gene. This gene shows striking sequence similarity to the EXT1 gene, and we have identified a four base deletion segregating with the phenotype. Both EXT1 and EXT2 show significant homology with one additional expressed sequence tag, defining a new multigene family of proteins with potential tumour suppressor activity.

The matrix Gla protein gene is a marker of the chondrogenesis cell lineage during mouse development

Matrix Gla protein (MGP) is, along with osteocalcin, a skeletal member of the family of extracellular mineral-binding Gla proteins. Although the precise function of these proteins remains obscure, circumstantial evidence suggests that they play a role in endochondral ossification. As a first step toward understanding MGP function we have performed a preliminary characterization of its promoter element and studied the developmental pattern of expression of this gene. DNA transfection experiments indicate that the mouse MGP promoter functions better in cells expressing the MGP gene than in cells that do not express the gene. During mouse development, MGP gene expression is detectable as early as day 10.5 of embryonic development (E10.5), before any skeletal structures are identifiable. In situ hybridization analysis shows that MGP mRNA is initially present at the mesenchymal epithelial interphase in lung and limb buds. As development proceeds, MGP gene is predominantly expressed in cells of the chondrocytic lineage in areas that will undergo endochondral ossification as well as in areas that will remain cartilaginous, such as the trachea and bronchi. In growth plate cartilage, MGP mRNA is present in resting, proliferative, and late hypertrophic chondrocytes. Surprisingly, MGP mRNA is absent from the early hypertrophic chondrocytes and from the osteoblasts. Finally, the MGP gene is expressed at a lower level in kidney medulla and uterus smooth muscle but not in brain, spleen, or heart during development. This study demonstrates that during development MGP gene expression occurs early and is predominant at the epithelial mesenchymal interfaces, principally of lung and limb buds, and in cells of the chondrocytic lineage. This finding raises the intriguing possibility that MGP may play distinct roles during embryogenesis and in the adult organism.

A slow release formulation of insulin as a treatment for osteoarthritis

OBJECTIVE

To examine the potential of insulin, in a sustained delivery system, as a treatment for arthritis.

DESIGN

The effect of insulin on matrix synthesis, matrix breakdown, and nitric oxide production in primary cartilage explants was examined. The activity of insulin on diseased cartilage from Dunkin Hartley guinea pigs, diabetic mice, and osteoarthritic patients was measured. The specificity of insulin stimulation was compared to that of IGF-I using osteoblasts and fibroblasts. Finally, the stability of insulin in a biologically relevant system was tested, and a slow-release formulation of insulin was developed and characterized.

RESULTS

In articular cartilage explants, insulin stimulated proteoglycan (PG) synthesis, inhibited PG release and nitric oxide production, and overcame the detrimental effects of interleukin 1 (IL-1). The mechanism whereby insulin decreased matrix breakdown was through inhibition of aggrecanase activity. Insulin was active on cartilage at concentrations at which insulin does not cross-react with insulin-like growth factor I (IGF-I) receptors nor stimulate proliferation of other cells types. The response of cartilage to insulin did not diminish with age or disease. Insulin stimulated matrix synthesis in osteoarthritic cartilage and local treatment with insulin overcame endogenous suppression of matrix synthesis in diabetic cartilage. Poly-lactic-coglycolic acid (PLGA) was found to be an effective carrier for delivery of insulin, and PLGA-Insulin was active on articular cartilage in vitro and in vivo.

CONCLUSIONS

As the incidence of arthritis increases with the aging population, an effective therapy to induce repair of cartilage is needed. Based on its biological activities, insulin appears to be an attractive protein therapeutic candidate. Maximum insulin effectiveness may require a sustained delivery system.

Hereditary multiple exostoses: confirmation of linkage to chromosomes 8 and 11

Hereditary multiple exostoses (EXT) is an autosomal dominant disorder characterized by the formation of cartilage capped prominences that develop from the epiphyses of the long bones. EXT is heterogeneous with three different locations currently identified on chromosomes 8, 11, and 19. Recently, we identified and studied 12 large multigenerational EXT families. Linkage analyses demonstrates that 6 of these families map to 8q24 and 6 to 11p. None of the families map to the chromosome 19 locus. The results suggest that there are two major loci, on chromosomes 8 and 11, involved in the cause of EXT. The locus on chromosome 19 remains to be confirmed.

The role of ion antiporters in the maintenance of intracellular pH in rat vascular smooth muscle cells

Vascular smooth muscle intracellular pH is maintained by the Na+/H+ and Cl-/HCO3- antiporters. The Na+/H+ exchanger is a major route of H+ extrusion in most eukaryotic cells and is present in vascular smooth muscle cells in a similar capacity. It extrudes H+ into the extracellular space in exchange for Na+. The Cl-/HCO3- exchanger plays an analogous role to lower the pH of vascular smooth muscle cells when increases in intracellular pH occur. Its activity has also been demonstrated in A7r5 and A10 vascular smooth muscle cells. The Na+/H+ exchanger is regulated by a number of agents which act through inositol trisphosphate/diacylglycerol, to stimulate the antiporter. Calcium-calmodulin dependent protein kinase may also activate the antiporter in vivo. Phosphorylation of the Cl-/HCO3- exchanger has also been observed but its physiological role is not known. Both these antiporters exist in the plasma membrane as integral proteins with free acidic cytoplasmic termini. These regions may be important in 'sensing' changes in intracellular pH, to which these antiporters respond.

Quantitative assessment of new MRI-based measurements to differentiate low and high stages of pelvic organ prolapse using support vector machines

INTRODUCTION AND HYPOTHESIS

The objective of this study was to quantitatively assess the ability of new MRI-based measurements to differentiate low and high stages of pelvic organ prolapse. New measurements representing pelvic structural characteristics are proposed and analyzed using support vector machines (SVM).

METHODS

This retrospective study used data from 207 women with different types and stages of prolapse. Their demographic information, clinical history, and dynamic MRI data were obtained from the database. New MRI measurements were extracted and analyzed based on these reference lines: pubococcygeal line (PCL), mid-pubic line (MPL), true conjugate line (TCL), obstetric conjugate line (OCL), and diagonal conjugate line (DCL). A classification model using SVM was designed to assess the impact of the features (variables) in classifying prolapse into low or high stage.

RESULTS

The classification model using SVM can accurately identified anterior prolapse with very high accuracy (>0.90), and apical and posterior prolapse with good accuracy (0.80 - 0.90). Two newly proposed MRI-based features were found to be significant in the identification of anterior and posterior prolapse: the angle between TCL and MPL for anterior prolapse, and the angle between DCL and PCL for posterior prolapse. The overall accuracy of posterior prolapse identification increased from 47% to 80% when the newly proposed MRI-based features were taken into consideration.

CONCLUSIONS

The proposed MRI-based measurements are effective in differentiating low and high stages of pelvic organ prolapse, particularly for posterior prolapse.

Abstract OT2-07-01: Phase 1/2 trial of the oncolytic virus, talimogene laherparpvec, in combination with neoadjuvant chemotherapy in stage II/III triple negative breast cancer

Background: The host anti-tumor immune response plays an important role in determining natural history and therapy response for early stage breast cancer. Tumors with high levels of lymphocytic infiltration appear to have a superior prognosis and response rate to neoadjuvant chemotherapy. However, these tumors are in the minority so methods to enhance tumor lymphocyte infiltration should be identified. The oncolytic virus, talimogene laherparpvec (TVEC) is a genetically modified HSV1 virus which selectively replicates in transformed cells while sparing normal tissue. This leads to lysis of infected tumor cells along with co-expression of GM-CSF to elicit an enhanced anti-tumor immune response. Prior data has shown TVEC can be safely combined with chemotherapy in other indications, so we launched an investigator initiated study to determine the safety and efficacy of combining TVEC with neoadjuvant dose dense chemotherapy in stage II-III TNBC.

Study design: The study is a phase 1 (2 dose levels of TVEC, 3+3 design) and phase 2 single arm Simon two stage combination trial. Primary endpoints of phase 1 is safety of intratumoral TVEC (DL1=106 PFU x 5 injections, DL2=106 PFU x 1 then 108 PFU x 4 injections) administered q2-3 weeks concurrently with weekly paclitaxel followed by standard dose dense AC x 4 and local therapy as indicated. Phase 2 primary endpoint is pCR rate of the study treatment, secondary endpoints include DFS, OS, immune correlates in resected tumor specimens. Eligibility criteria includes females >17 years old, newly diagnosed T2-3N0-3 TNBC, adequate organ function, primary tumor amenable to injection with TVEC, no immunosuppressive or autoimmune conditions, no inflammatory or bilateral/multifocal disease. Sample size is up to 49 patients (12 phase 1, 37 phase 2) with 80% power to detect increase in pCR rate from 30% to 50% with one sided p=.1 in phase 2.

Study status: This novel Amgen supported investigator initiated study activated to accrual 3/2017 and first patient on study was on 5/2017. The study is currently open only at the Moffitt Cancer Center. Target study completion date 8/2021. (NCT02779855)

Citation Format: Soliman HH, Hogue D, Han H, Lee C, Ismail-Khan R, Khong H, Niell B, Czerniecki B. Phase 1/2 trial of the oncolytic virus, talimogene laherparpvec, in combination with neoadjuvant chemotherapy in stage II/III triple negative breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr OT2-07-01.

Hereditary multiple exostosis and chondrosarcoma: linkage to chromosome II and loss of heterozygosity for EXT-linked markers on chromosomes II and 8

Hereditary multiple exostosis (EXT) is an autosomal dominant disorder characterized by bony exostoses at the ends of the long bones. Linkage studies have recently suggested that there are three chromosomal locations for EXT genes, 8q24.1 (EXT1), the pericentric region of 11 (EXT2), and 19p (EXT3). As part of a larger study to determine the frequencies of the three EXT types in the United States, we have ascertained a large multigenerational family with EXT and one family member with a chondrosarcoma. This family demonstrated linkage of the disease to chromosome 11 markers. The constitutional and tumor DNAs from the affected family member were compared using short-tandem-repeat markers from chromosomes 8, 11, and 19. Loss of heterozygosity (LOH) in the tumor was observed for chromosome 8 and 11 markers, but chromosome 19 markers were intact. An apparent deletion of the marker D11S903 was observed in constitutional DNA from all affected individuals and in the tumor sample. These results indicate that the EXT2 gene maps to the region containing marker D11S903, which is flanked by markers D11S1355 and D11S1361. Additional constitutional and chondrosarcoma DNA pairs from six unrelated individuals, two of whom had EXT, were similarly analyzed. One tumor from an individual with EXT demonstrated LOH for chromosome 8 markers, and a person with a sporadic chondrosarcoma was found to have tumor-specific LOH and a homozygous deletion of chromosome 11 markers. These findings suggest that EXT genes may be tumor-suppressor genes and that the initiation of tumor development may follow a multistep model.

High resolution data visualization and machine learning prediction of free chlorine residual in a green building water system

People spend most of their time indoors and are exposed to numerous contaminants in the built environment. Water management plans implemented in buildings are designed to manage the risks of preventable diseases caused by drinking water contaminants such as opportunistic pathogens (e.g., Legionella spp.), metals, and disinfection by-products (DBPs). However, specialized training required to implement water management plans and heterogeneity in building characteristics limit their widespread adoption. Implementation of machine learning and artificial intelligence (ML/AI) models in building water settings presents an opportunity for faster, more widespread use of data-driven water quality management approaches. We demonstrate the utility of Random Forest and Long Short-Term Memory (LSTM) ML models for predicting a key public health parameter, free chlorine residual, as a function of data collected from building water quality sensors (ORP, pH, conductivity, and temperature) as well as WiFi signals as a proxy for building occupancy and water usage in a "green" Leadership in Energy and Environmental Design (LEED) commercial and institutional building. The models successfully predicted free chlorine residual declines below 0.2 ppm, a common minimum reference level for public health protection in drinking water distribution systems. The predictions were valid up to 5 min in advance, and in some cases reasonably accurate up to 24 h in advance, presenting opportunities for proactive water quality management as part of a sense-analyze-decide framework. An online data dashboard for visualizing water quality in the building is presented, with the potential to link these approaches for real-time water quality management.

Hereditary multiple exostoses (EXT): mutational studies of familial EXT1 cases and EXT-associated malignancies

Hereditary multiple exostoses (EXT) is an autosomal dominant disorder characterized by the formation of cartilage-capped prominences that develop from the growth centers of the long bones. EXT is genetically heterogeneous, with three loci, currently identified on chromosomes 8q24.1, 11p13, and 19q. The EXT1 gene, located on chromosome 8q24.1, has been cloned and is encoded by a 3.4-kb cDNA. Five mutations in the EXT1 gene have been identified--four germ-line mutations, including two unrelated families with the same mutation, and one somatic mutation in a patient with chondrosarcoma. Four of the mutations identified resulted in frameshifts and premature termination codons, while the fifth mutation resulted in a substitution of leucine for arginine. Loss of heterozygosity (LOH) analysis of chondrosarcomas and chondroblastomas revealed multiple LOH events at loci on chromosomes 3q, 8q, 10q, and 19q. One sporadic chondrosarcoma demonstrated LOH for EXT1 and EXT3, while a second underwent LOH for EXT2 and chromosome 10. A third chondrosarcoma underwent LOH for EXT1 and chromosome 3q. These results agree with previous findings that mutations at EXT1 and multiple genetic events that include LOH at other loci may be required for the development of chondrosarcoma.

Delineation of a contiguous gene syndrome with multiple exostoses, enlarged parietal foramina, craniofacial dysostosis, and mental retardation, caused by deletions in the short arm of chromosome 11

A contiguous gene syndrome due to deletions of the proximal short arm of chromosome 11 is described in eight patients belonging to four families. The main clinical features are multiple exostoses, enlarged parietal foramina, craniofacial dysostosis, and mental retardation. The patients have cytogenetic and/or molecular deletions of chromosome 11p11-p13. These deletions are located between the centromere and D11S914 in a region of approximately 20cM. The present study confirms the presence of a multiple exostoses gene on chromosome 11p. Furthermore, it suggests that the gene for isolated foramina parietalie permagna and genes associated with craniofacial dysostosis and mental retardation reside in the same chromosomal region.