Surgical Anatomy and Exercises Using the Chicken Thigh Sciatic Nerve for Microsurgery Training

Introduction  Vessel repair in a chicken thigh is commonly used in microsurgery training model. The sciatic nerve is closely associated with the vessels and has been used for training nerve coaptation, which has different technical considerations from vessel anastomosis. We describe in detail the relevant surgical anatomy and training exercises that can be used with this model. Methods  With 32 fresh store-bought chicken thighs, 16 were used to analyze the gross and histological features of the sciatic nerve, and 16 were intended to create and perform training models. Results  The average visible length of the nerve in the thigh was 51 mm (standard deviation [SD] 2.57 mm). The average diameter of the nerve was 2 mm (SD 0.33 mm) and was largest at its proximal end (3.21 mm, SD 0.27 mm). The nerve consistently branched into two along the chicken thigh, with more branching subsequently. This simulation model is appropriate not only for the classical end-to-end epineural suture, but also for advanced exercises, in terms of longitudinal fasciculus dissection, mismatched size nerve transfer, injured nerve preparation, and vein conduit technique. Dyeing of nerve fascicles enhanced the visibility of nerve surface quality. Conclusion  The sciatic nerve in the chicken thigh is a suitable and accessible model for microsurgery training. The branching and fascicular patterns of the nerve lends itself well to both novice training and advanced simulation. We have incorporated this model into our training curricula.

Achieving Molecular Recognition of Structural Analogues in Surface-Enhanced Raman Spectroscopy: Inducing Charge and Geometry Complementarity to Mimic Molecular Docking

Molecular recognition of complex isomeric biomolecules remains challenging in surface-enhanced Raman scattering (SERS) spectroscopy due to their small Raman cross-sections and/or poor surface affinities. To date, the use of molecular probes has achieved excellent molecular sensitivities but still suffers from poor spectral specificity. Here, we induce "charge and geometry complementarity" between probe and analyte as a key strategy to achieve high spectral specificity for effective SERS molecular recognition of structural analogues. We employ 4-mercaptopyridine (MPY) as the probe, and chondroitin sulfate (CS) disaccharides with isomeric sulfation patterns as our proof-of-concept study. Our experimental and in silico studies reveal that "charge and geometry complementarity" between MPY's binding pocket and the CS sulfation patterns drives the formation of site-specific, multidentate interactions at the respective CS isomerism sites, which "locks" each CS in its analogue-specific complex geometry, akin to molecular docking events. Leveraging the resultant spectral fingerprints, we achieve > 97 % classification accuracy for 4 CSs and 5 potential structural interferences, as well as attain multiplex CS quantification with < 3 % prediction error. These insights could enable practical SERS differentiation of biologically important isomers to meet the burgeoning demand for fast-responding applications across various fields such as biodiagnostics, food and environmental surveillance.

SIRIUS, Ultra-Scintillating Upconversion Breast Implant for Remote Orthotopic Photodynamic Therapy

Present day strategies for delivery of wireless photodynamic therapy (PDT) to deep-seated targets are limited by the inadequacy of irradiance and insufficient therapeutic depth. Here we report the design and preclinical validation of a flexible wireless upconversion nanoparticle (UCNP) implant (SIRIUS) that is capable of large field, high intensity illumination for PDT of deep-seated tumors. The implant achieves this by incorporating submicrometer core-shell-shell NaYF₄ UCNPs into its design, which significantly enhances upconversion efficiency and mitigates light loss from surface quenching. We demonstrate the efficacy of SIRIUS UCNP implant mediated PDT in preclinical breast cancer disease models. In our in vitro experiments, SIRIUS directed 5-Aminolevulinic Acid (5-ALA) based wireless PDT leads to significant reactive oxygen species (ROS) generation and tumor apoptosis in hormonal receptor+/HER2+ (MCF7) and triple-negative (MDA-MB-231) breast cancer cell lines. In our in vivo rodent model, SIRIUS-driven PDT is shown to be significant in regressing tumors when applied to orthotopically inoculated breast tumors. Following successful preclinical validation, we also describe a clinical prototype of UCNP breast implant with potential dual cosmetic and onco-therapeutic functions. SIRIUS is an upconversion breast implant for wireless PDT that fulfils all the design prerequisites necessary for seamless clinical translation.

C1QBP Mediates Breast Cancer Cell Proliferation and Growth via Multiple Potential Signalling Pathways

Breast carcinoma is the most prevalent cancer in women globally, with complex genetic and molecular mechanisms that underlie its development and progression. Several challenges such as metastasis and drug resistance limit the prognosis of breast cancer, and hence a constant search for better treatment regimes, including novel molecular therapeutic targets is necessary. Complement component 1, q subcomponent binding protein (C1QBP), a promising molecular target, has been implicated in breast carcinogenesis. In this study, the role of C1QBP in breast cancer progression, in particular cancer cell growth, was determined in triple negative MDA-MB-231 breast cancer cells. Depletion of C1QBP decreased cell proliferation, whereas the opposite effect was observed when C1QBP was overexpressed in MDA-MB-231 cells. Furthermore, gene expression profiling and pathway analysis in C1QBP depleted cells revealed that C1QBP regulates several signaling pathways crucial for cell growth and survival. Taken together, these findings provide a deeper comprehension of the role of C1QBP in triple negative breast cancer, and could possibly pave the way for future advancement of C1QBP-targeted breast cancer therapy.

Theranostic Applications of Glycosaminoglycans in Metastatic Renal Cell Carcinoma

Renal cell carcinoma (RCC) makes up the majority of kidney cancers, with a poor prognosis for metastatic RCC (mRCC). Challenges faced in the management of mRCC, include a lack of reliable prognostic markers and biomarkers for precise monitoring of disease treatment, together with the potential risk of toxicity associated with more recent therapeutic options. Glycosaminoglycans (GAGs) are a class of carbohydrates that can be categorized into four main subclasses, viz., chondroitin sulfate, hyaluronic acid, heparan sulfate and keratan sulfate. GAGs are known to be closely associated with cancer progression and modulation of metastasis by modification of the tumor microenvironment. Alterations of expression, composition and spatiotemporal distribution of GAGs in the extracellular matrix (ECM), dysregulate ECM functions and drive cancer invasion. In this review, we focus on the clinical utility of GAGs as biomarkers for mRCC (which is important for risk stratification and strategizing effective treatment protocols), as well as potential therapeutic targets that could benefit patients afflicted with advanced RCC. Besides GAG-targeted therapies that holds promise in mRCC, other potential strategies include utilizing GAGs as drug carriers and their mimetics to counter cancer progression, and enhance immunotherapy through binding and transducing signals for immune mediators.

The natural antisense transcript HAS2-AS1 regulates breast cancer cells aggressiveness independently from hyaluronan metabolism

Hyaluronan (HA) is a ubiquitous extracellular matrix component playing a crucial role in the regulation of cell behaviors, including cancer. Aggressive breast cancer cells tend to proliferate, migrate and metastatize. Notably, triple-negative breast cancer cells lacking the expression of estrogen receptor (ER) as well as progesterone receptor and HER2 are more aggressive than ER-positive ones. As currently no targeted therapy is available for triple-negative breast cancer, the identification of novel therapeutic targets has a high clinical priority. In ER-negative cells, tumoral behavior can be reduced by inhibiting HA synthesis or silencing the enzymes involved in its metabolism, such as HA synthase 2 (HAS2). HAS2-AS1 is a long non-coding RNA belonging to the natural antisense transcript family which is known to favor HAS2 gene expression and HA synthesis, thus bolstering malignant progression in brain, ovary, and lung tumors. As the role of HAS2-AS1 has not yet been investigated in breast cancer, in this work we report that ER-positive breast cancers had lower HAS2-AS1 expression compared to ER-negative tumors. Moreover, the survival of patients with ER-negative tumors was higher when the expression of HAS2-AS1 was elevated. Experiments with ER-negative cell lines as MDA-MB-231 and Hs 578T revealed that the overexpression of either the full-length HAS2-AS1 or its exon 2 long or short isoforms alone, strongly reduced cell viability, migration, and invasion, whereas HAS2-AS1 silencing increased cell aggressiveness. Unexpectedly, in these ER-negative cell lines, HAS2-AS1 is involved neither in the regulation of HAS2 nor in HA deposition. Finally, transcriptome analysis revealed that HAS2-AS1 modulation affected several pathways, including apoptosis, proliferation, motility, adhesion, epithelial to mesenchymal transition, and signaling, describing this long non-coding RNA as an important regulator of breast cancer cells aggressiveness.

KIF21A regulates breast cancer aggressiveness and is prognostic of patient survival and tumor recurrence

PURPOSE

Invasion of carcinoma cells into surrounding tissue affects breast cancer staging, influences choice of treatment, and impacts on patient outcome. KIF21A is a member of the kinesin superfamily that has been well-studied in congenital extraocular muscle fibrosis. However, its biological relevance in breast cancer is unknown. This study investigated the functional roles of KIF21A in this malignancy and examined its expression pattern in breast cancer tissue.

METHODS

The function of KIF21A in breast carcinoma was studied in vitro by silencing its expression in breast cancer cells and examining the changes in cellular activities. Immunohistochemical staining of breast cancer tissue microarrays was performed to determine the expression patterns of KIF21A.

RESULTS

Knocking down the expression of KIF21A using siRNA in MDA-MB-231 and MCF7 human breast cancer cells resulted in significant decreases in tumor cell migration and invasiveness. This was associated with reduced Patched 1 expression and F-actin microfilaments. Additionally, the number of focal adhesion kinase- and paxillin-associated focal adhesions was increased. Immunohistochemical staining of breast cancer tissue microarrays showed that KIF21A was expressed in both the cytoplasmic and nuclear compartments of carcinoma cells. Predominance of cytoplasmic KIF21A was significantly associated with larger tumors and high grade cancer, and prognostic of cause-specific overall patient survival and breast cancer recurrence.

CONCLUSION

The data demonstrates that KIF21A is an important regulator of breast cancer aggressiveness and may be useful in refining prognostication of this malignant disease.

Epigenetic derepression converts PPARγ into a druggable target in triple-negative and endocrine-resistant breast cancers

Clinical trials repurposing peroxisome proliferator-activated receptor-gamma (PPARγ) agonists as anticancer agents have exhibited lackluster efficacy across a variety of tumor types. Here, we report that increased PPARG expression is associated with a better prognosis but is anticorrelated with histone deacetylase (HDAC) 1 and 2 expressions. We show that HDAC overexpression blunts anti-proliferative and anti-angiogenic responses to PPARγ agonists via transcriptional and post-translational mechanisms, however, these can be neutralized with clinically approved and experimental HDAC inhibitors. Supporting this notion, concomitant treatment with HDAC inhibitors was required to license the tumor-suppressive effects of PPARγ agonists in triple-negative and endocrine-refractory breast cancer cells, and combination therapy also restrained angiogenesis in a tube formation assay. This combination was also synergistic in estrogen receptor-alpha (ERα)-positive cells because HDAC blockade abrogated ERα interference with PPARγ-regulated transcription. Following a pharmacokinetics optimization study, the combination of rosiglitazone and a potent pan-HDAC inhibitor, LBH589, stalled disease progression in a mouse model of triple-negative breast cancer greater than either of the monotherapies, while exhibiting a favorable safety profile. Our findings account for historical observations of de-novo resistance to PPARγ agonist monotherapy and propound a therapeutically cogent intervention against two aggressive breast cancer subtypes.

Knockdown of the prognostic cancer stem cell marker Musashi-1 decreases radio-resistance while enhancing apoptosis in hormone receptor-positive breast cancer cells via p21WAF1/CIP1

Purpose

While the stem cell marker Musashi-1 (MSI-1) has been identified as a key player in a wide array of malignancies, few findings exist on its prognostic relevance and relevance for cancer cell death and therapy resistance in breast cancer.

Methods

First, we determined prognostic relevance of MSI-1 in database analyses regarding multiple survival outcomes. To substantiate findings, MSI-1 was artificially downregulated in MCF-7 breast cancer cells and implications for cancer stem cell markers, cell apoptosis and apoptosis regulator p21, proliferation and radiation response were analyzed via flow cytometry and colony formation. Radiation-induced p21 expression changes were investigated using a dataset containing patient samples obtained before and after irradiation and own in vitro experiments.

Results

MSI-1 is a negative prognostic marker for disease-free and distant metastasis-free survival in breast cancer and tends to negatively influence overall survival. MSI-1 knockdown downregulated stem cell gene expression and proliferation, but increased p21 levels and apoptosis. Similar to the MSI-1 knockdown effect, p21 expression was strongly increased after irradiation and was expressed at even higher levels in MSI-1 knockdown cells after irradiation. Finally, combined use of MSI-1 silencing and irradiation reduced cancer cell survival.

Conclusion

MSI-1 is a prognostic marker in breast cancer. MSI-1 silencing downregulates proliferation while increasing apoptosis. The anti-proliferation mediator p21 was upregulated independently after both MSI-1 knockdown and irradiation and even more after both treatments combined, suggesting synergistic potential. Radio-sensitization effects after combining radiation and MSI-1 knockdown underline the potential of MSI-1 as a therapeutic target.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00432-021-03743-y.

Roles of Interferon Induced Protein with Tetratricopeptide Repeats (IFIT) Family in Cancer

The Interferon-induced protein with the tetratricopeptide repeats (IFIT) family is an important component of the antiviral immune response. There are currently four known IFIT family members in humans, namely IFIT1, IFIT2, IFIT3 and IFIT5. Recent discoveries have brought attention to the significant roles of IFITs in cancer. This review summarises current knowledge on the biological roles of different IFIT proteins in various types of malignant neoplasm and highlights the potential use of these molecules as cancer biomarkers and prognostic factors.

Prognostic significance of phosphoglycerate dehydrogenase in breast cancer

PURPOSE

Breast cancer is the most common type of cancer affecting women worldwide. Phosphoglycerate dehydrogenase (PHGDH) is an oxidoreductase in the serine biosynthesis pathway. Although it has been reported to affect growth of various tumors, its role in breast cancer is largely unknown. This study aimed to analyze the expression of PHGDH in breast cancer tissue samples and to determine if PHGDH regulates breast cancer cell proliferation.

METHODS

Tissue microarrays consisting of 305 cases of breast invasive ductal carcinoma were used for immunohistochemical evaluation of PHGDH expression. The role of PHGDH in breast cancer was investigated in vitro by knocking down its expression and determining the effect on cell proliferation and cell cycling, and in ovo by using a chorioallantoic membrane (CAM) assay.

RESULTS

Immunohistochemical examination showed that PHGDH is mainly localized in the cytoplasm of breast cancer cells and significantly associated with higher cancer grade, larger tumor size, increased PCNA expression, and lymph node positivity. Analysis of the GOBO dataset of 737 patients demonstrated that increased PHGDH expression was associated with poorer overall survival. Knockdown of PHGDH expression in breast cancer cells in vitro resulted in a decrease in cell proliferation, reduction in cells entering the S phase of the cell cycle, and downregulation of various cell cycle regulatory genes. The volume of breast tumor in an in ovo CAM assay was found to be smaller when PHGDH was silenced.

CONCLUSION

The findings suggest that PHGDH has a regulatory role in breast cancer cell proliferation and may be a potential prognostic marker and therapeutic target in breast cancer.

The Role of Hydroxychloroquine in COVID-19 Treatment: A Systematic Review and Meta-Analysis

Objective: A systematic review and meta-analysis was carried out to examine the role of hydroxychloroquine (HCQ) in the treatment of COVID-19. Methods: We performed a systematic search in PubMed, Scopus, Embase, Cochrane- Library, Web of Science, Google Scholar, and medRxiv pre-print databases using available MeSH terms for COVID-19 and hydroxychloroquine. Data from all studies that focused on the effectiveness of HCQ with or without the addition of azithromycin (AZM) in confirmed COVID-19 patients, which were published up to 12 September 2020, were collated for analysis using CMA v.2.2.064. Results: Our systematic review retrieved 41 studies. Among these, 37 studies including 45,913 participants fulfilled the criteria for subsequent meta-analysis. The data showed no significant difference in treatment efficacy between the HCQ and control groups (RR: 1.02, 95% CI, 0.81–1.27). Combination of HCQ with AZM also did not lead to improved treatment outcomes (RR: 1.26, 95% CI, 0.91–1.74). Furthermore, the mortality difference was not significant, neither in HCQ treatment group (RR: 0.86, 95% CI, 0.71–1.03) nor in HCQ plus AZM treatment group (RR: 1.28, 95% CI, 0.76–2.14) in comparison to controls. Meta-regression analysis showed that age was the factor that significantly affected mortality (P<0.00001). Conclusion: The meta-analysis found that there was no clinical benefit of using either HCQ by itself or in combination with AZM for the treatment of COVID-19 patients. Hence, it may be prudent for clinicians and researchers to focus on other therapeutic options that may show greater promise in this disease. Keywords: Azithromycin, coronavirus outbreaks, pandemic, SARS-CoV-2 disease

Diagnostic value of serum HER2 levels in breast cancer: a systematic review and meta-analysis

BACKGROUND

Measurement of serum human epidermal growth factor receptor-2 (HER-2/neu) levels might play an essential role as a diagnostic/screening marker for the early selection of therapeutic approaches and predict prognosis in breast cancer patients. We aimed to undertake a systematic review and meta-analysis focusing on the diagnostic/screening value of serum HER-2 levels in comparison to routine methods.

METHODS

We performed a systematic search via PubMed, Scopus, Cochrane-Library, and Web of Science databases for human diagnostic studies reporting the levels of serum HER-2 in breast cancer patients, which was confirmed using the histopathological examination. Meta-analyses were carried out for sensitivity, specificity, accuracy, area under the ROC curve (AUC), positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (PLR), and negative likelihood ratio (NLR).

RESULTS

Fourteen studies entered into this investigation. The meta-analysis indicated the low sensitivity for serum HER2 levels (Sensitivity: 53.05, 95%CI 40.82-65.28), but reasonable specificity of 79.27 (95%CI 73.02-85.51), accuracy of 72.06 (95%CI 67.04-77.08) and AUC of 0.79 (95%CI 0.66-0.92). We also found a significant differences for PPV (PPV: 56.18, 95%CI 44.16-68.20), NPV (NPV: 76.93, 95%CI 69.56-84.31), PLR (PLR: 2.10, 95%CI 1.69-2.50) and NLR (NLR: 0.58, 95%CI 0.44-0.71).

CONCLUSION

Our findings revealed that although serum HER-2 levels showed low se nsitivity for breast cancer diagnosis, its specificity, accuracy and AUC were reasonable. Hence, it seems that the measurement of serum HER-2 levels can play a significant role as a verification test for initial negative screening test results, especially in low-income regions due to its cost-effectiveness and ease of implementation.

The Role of Hydroxychloroquine in COVID-19: A Systematic Review and Meta-Analysis

OBJECTIVE

A systematic review and meta-analysis was carried out to examine the role of hydroxychloroquine (HCQ) in the treatment of COVID-19.

METHODS

We performed a systematic search in PubMed, Scopus, Embase, CochraneLibrary, Web of Science, Google Scholar, and medRxiv pre-print databases using available MeSH terms for COVID-19 and hydroxychloroquine. Data from all studies that focused on the effectiveness of HCQ with or without the addition of azithromycin (AZM) in confirmed COVID-19 patients, which were published up to 12 September 2020, were collated for analysis using CMA v.2.2.064.

RESULTS

Our systematic review retrieved 41 studies. Among these, 37 studies including 45,913 participants fulfilled the criteria for subsequent meta-analysis. The data showed no significant difference in treatment efficacy between the HCQ and control groups (RR: 1.02, 95% CI, 0.81-1.27). Combination of HCQ with AZM also did not lead to improved treatment outcomes (RR: 1.26, 95% CI, 0.91-1.74). Furthermore, the mortality difference was not significant, neither in HCQ treatment group (RR: 0.86, 95% CI, 0.71-1.03) nor in HCQ plus AZM treatment group (RR: 1.28, 95% CI, 0.76-2.14) in comparison to controls. Meta-regression analysis showed that age was the factor that significantly affected mortality (P<0.00001).

CONCLUSION

The meta-analysis found that there was no clinical benefit of using either HCQ by itself or in combination with AZM for the treatment of COVID-19 patients. Hence, it may be prudent for clinicians and researchers to focus on other therapeutic options that may show greater promise in this disease.

The heparan sulfate proteoglycan syndecan-1 regulates colon cancer stem cell function via a focal adhesion kinase-Wnt signaling axis

In colon cancer, downregulation of the transmembrane heparan sulfate proteoglycan syndecan-1 (Sdc-1) is associated with increased invasiveness, metastasis, and dedifferentiation. As Sdc-1 modulates signaling pathways relevant to stem cell function, we tested the hypothesis that it may regulate a tumor-initiating cell phenotype. Sdc-1 small-interfering RNA knockdown in the human colon cancer cell lines Caco2 and HT-29 resulted in an increased side population (SP), enhanced aldehyde dehydrogenase 1 activity, and higher expression of CD133, LGR5, EPCAM, NANOG, SRY (sex-determining region Y)-box 2, KLF2, and TCF4/TCF7L2. Sdc-1 knockdown enhanced sphere formation, cell viability, Matrigel invasiveness, and epithelial-to-mesenchymal transition-related gene expression. Sdc-1-depleted HT-29 xenograft growth was increased compared to controls. Decreased Sdc-1 expression was associated with an increased activation of β1-integrins, focal adhesion kinase (FAK), and wingless-type (Wnt) signaling. Pharmacological FAK and Wnt inhibition blocked the enhanced stem cell phenotype and invasive growth. Sequential flow cytometric SP enrichment substantially enhanced the stem cell phenotype of Sdc-1-depleted cells, which showed increased resistance to doxorubicin chemotherapy and irradiation. In conclusion, Sdc-1 depletion cooperatively enhances activation of integrins and FAK, which then generates signals for increased invasiveness and cancer stem cell properties. Our findings may provide a novel concept to target a stemness-associated signaling axis as a therapeutic strategy to reduce metastatic spread and cancer recurrence. DATABASES: The GEO accession number of the Affymetrix transcriptomic screening is GSE58751.

Protecting-Group-Free Synthesis of Chondroitin 6-Sulfate Disaccharide and Tetrasaccharide

Chondroitin 6-sulfate (CS-C) is an important glycosaminoglycan that regulates many physiological functions including the development, progression, and metastasis of cancer. To understand its mechanism of action at the molecular level, CS-C molecules of defined length are required. A protecting group-free synthesis of CS-C disaccharide and tetrasaccharide from the CS-A polymer that involves only three steps and furnishes CS-O disaccharide and tetrasaccharide as intermediates is reported.

In Vitro Evaluation of Candidate Gene Targets for Cancer Therapy

Discovery and development of gene targets for cancer therapeutics are lengthy and highly costly processes. Identification and evaluation of candidate gene targets are of fundamental importance. RNA interference allows candidate genes to be specifically and effectively knocked down in cancer cells. This tool can be easily incorporated into a loss-of-function approach in the initial evaluation of candidate gene targets for cancer treatment prior to moving on to animal studies and clinical trials. This chapter describes a relatively simple and straightforward protocol that makes use of small interfering RNA to achieve knockdown of the candidate gene target and to evaluate the resultant effects on four aspects of cancer cell behavior: migration, invasion, proliferation, and adhesion.

Small Maf functions in the maintenance of germline stem cells in the Drosophila testis

Reactive oxygen species (ROS) are byproducts generated during normal cellular metabolism, and redox states have been shown to influence stem cell self-renewal and lineage commitment across phyla. However, the downstream effectors of ROS signaling that control stem cell behavior remain largely unexplored. Here, we used the Drosophila testis as an in vivo model to identify ROS-induced effectors that are involved in the differentiation process of germline stem cells (GSCs). In the Affymetrix microarray analysis, 152 genes were either upregulated or downregulated during GSC differentiation induced by elevated levels of ROS, and a follow-up validation of the gene expression by qRT-PCR showed a Spearman's rho of 0.9173 (P<0.0001). Notably, 47 (31%) of the identified genes had no predicted molecular function or recognizable protein domain. These suggest the robustness of this microarray analysis, which identified many uncharacterized genes, possibly with an essential role in ROS-induced GSC differentiation. We also showed that maf-S is transcriptionally downregulated by oxidative stress, and that maf-S knockdown promotes GSC differentiation but Maf-S overexpression conversely results in an over-growth of GSC-like cells by promoting the mitotic activity of germ cell lineage. Together with the facts that Maf-S regulates ROS levels and genetically interacts with Keap1/Nrf2 in GSC maintenance, our study suggests that Maf-S plays an important role in the Drosophila testis GSC maintenance by participating in the regulation of redox homeostasis.

Divergent Synthesis of Chondroitin Sulfate Disaccharides and Identification of Sulfate Motifs that Inhibit Triple Negative Breast Cancer

Glycosaminoglycans (GAGs) regulate many important physiological processes. A pertinent issue to address is whether GAGs encode important functional information via introduction of position specific sulfate groups in the GAG structure. However, procurement of pure, homogenous GAG motifs to probe the “sulfation code” is a challenging task due to isolation difficulty and structural complexity. To this end, we devised a versatile synthetic strategy to obtain all the 16 theoretically possible sulfation patterns in the chondroitin sulfate (CS) repeating unit; these include rare but potentially important sulfated motifs which have not been isolated earlier. Biological evaluation indicated that CS sulfation patterns had differing effects for different breast cancer cell types, and the greatest inhibitory effect was observed for the most aggressive, triple negative breast cancer cell line MDA-MB-231.

Sulfated glycosaminoglycans from crown-of-thorns Acanthaster planci - extraction and quantification analysis

In this article, the novel inventive steps for the extraction and quantification of sulfated glycosaminoglycan (GAG) from Acanthaster planci starfish, generally known as crown-of-thorns (COT), are reported. Starfish have been implicated with collagenous distributions within their body anatomy, thus making it a prima facie fact searching for the possibility that GAGs can be isolated from COT. In this study, total-, N-, and O-sulfated GAGs were extracted from three anatomical regions of the COT (integument, internal tissue, and coelomic fluid) and comparison was made. The result showed that body region of COT seemed to contain higher amount of sulfated GAGs as opposed to the arm region (55.79 ± 0.65 μg/mg was the highest amount in the body extracted from its coelomic fluid and 32.28 ± 3.14 μg/mg was the highest amount in the arm extracted from its internal tissue). COT's integument and coelomic fluid from its body region possessed the highest total of sulfated GAGs content with no significant difference (P < 0.05) between the two. All GAGs from COT comprised a higher percentage of N-sulfated GAGs than its counterpart, the O-sulfated GAGs. When compared with a similar previous study that used sea cucumbers as the sulfated GAGs source, COT possessed more total sulfated GAGs content per milligram as compared with the sea cucumber generally. This result seems to unveil this marine species' advantage per se pertaining to GAGs extraction biomass applicability. Thus, COT could now be the better alternative source for production technology of total-, N-, and O-sulfated GAGs.

Organization of the neuroepithelial actin cytoskeleton is regulated by heparan sulfation during neurulation

Heparan sulfate and cytoskeletal actin microfilaments have both been shown to be important regulators of neural tube closure during embryonic development. To determine the functional relationship of these two molecules in formation of the spinal neural tube, we cultured ARC mouse embryos at embryonic day E8.5 in the presence of chlorate, a competitive inhibitor of glycosaminoglycan sulfation, and examined the effects on organization of actin microfilaments in the neuroepithelium. Compared against embryos cultured under control conditions, chlorate-treated embryos had shortened posterior neuropore, a loss of median hinge point formation and increased bending at the paired dorsolateral hinge points. Furthermore, apical organization of actin microfilaments in the neuroepithelial cells was absent, and this was associated with convex bending of the neuroepithelium. The results suggest that heparan sulfate is an important determinant of cytoskeletal actin organization during spinal neurulation, and that its biological action is dependent on sulfation of the heparan molecule.

Targeting of syndecan-1 by microRNA miR-10b promotes breast cancer cell motility and invasiveness via a Rho-GTPase- and E-cadherin-dependent mechanism

microRNAs are small endogenous noncoding RNAs, which post-transcriptionally regulate gene expression. In breast cancer, overexpression of the transmembrane heparan sulfate proteoglycan syndecan-1, a predicted target of the oncomiR miR-10b, correlates with poor clinical outcome. To investigate the potential functional relationship of miR-10b and syndecan-1, MDA-MB-231 and MCF-7 breast cancer cells were transiently transfected with pre-miR-10b, syndecan-1 siRNA or control reagents, respectively. Altered cell behavior was monitored by proliferation, migration and invasion chamber assays, and time-lapse video microscopy. miR-10b overexpression induced post-transcriptional downregulation of syndecan-1, as demonstrated by quantitative real-time PCR (qPCR), flow cytometry, and 3'UTR luciferase assays, resulting in increased cancer cell migration and matrigel invasiveness. Syndecan-1 silencing generated a copy of this phenotype. Adhesion to fibronectin and laminin and basal cell proliferation was increased. Syndecan-1 coimmunoprecipitated with focal adhesion kinase, which showed increased activation upon syndecan-1 depletion. Affymetrix screening and confirmatory qPCR and Western blotting analysis of syndecan-1-deficient cells revealed upregulation of ATF-2, COX-2, cadherin-11, vinculin, actin γ 2, MYL9, transgelin-1, RhoA/C, matrix metalloproteinase 2 (MMP2) and heparanase, and downregulation of AML1/RUNX1, E-cadherin, CLDN1, p21WAF/CIP, cyclin-dependent kinase 6, TLR-4, PAI1/2, Collagen1alpha1, JHDM1D, Mpp4, MMP9, matrilin-2 and ANXA3/A10. Video microscopy demonstrated massively increased Rho kinase-dependent motility of syndecan-1-depleted cells, which displayed increased filopodia formation. We conclude that syndecan-1 is a novel target of the oncomiR miR-10b. Rho-GTPase-dependent modulation of cytoskeletal function and downregulation of E-cadherin expression are identified as relevant effectors of the miR-10b-syndecan-1 axis, which emerges as a promising target for the development of new therapeutic approaches for breast cancer.

Effect of targeting of syndecan-1 by microRNA miR-10b on breast cancer cell motility and invasiveness via a rho-GTPase- and E-cadherin-dependent mechanism

e21041

Background: microRNAs are small endogenous non-coding RNAs, which posttranscriptionally regulate gene expression. In breast cancer, overexpression of the transmembrane heparan sulfate proteoglycan syndecan-1, a predicted target of the oncomiR miR-10b, correlates with poor clinical outcome. Here, we investigatet the potential functional relationship of miR-10b and syndecan-1 in an in vitro study. Methods: MDA-MB-231 and MCF-7 breast cancer cells were transiently transfected with pre-miR-10b, syndecan-1 siRNA or control reagents, respectively. Altered cell behaviour was monitored by proliferation, migration and invasion chamber assays, and time-lapse video microscopy. Results: miR-10b overexpression induced posttranscriptional downregulation of syndecan-1, as demonstrated by qPCR, flow cytometry, and 3’UTR luciferase assays, resulting in increased cancer cell migration and matrigel invasiveness. Syndecan-1 silencing generated a copy of this phenotype. Adhesion to fibronectin and laminin and basal cell proliferation were increased. Syndecan-1 co-immunoprecipitated with focal adhesion kinase, which showed increased activation upon syndecan-1 depletion. Affymetrix screening and confirmatory qPCR and Western blotting analysis of syndecan-1 deficient cells revealed upregulation of ATF-2, COX- 2, cadherin-11, vinculin, ACTG2, MYL9, transgelin-1, RhoA/C, MMP2 and heparanase, and downregulation of AML1/RUNX1, E-cadherin, CLDN1, p21WAF/CIP, Cdk6, TLR-4, PAI1/2, Collagen1alpha1, JHDM1D, Mpp4, MMP9, matrilin-2 and ANXA3/A10. Video microscopy demonstrated massively increased Rho kinase-dependent motility of syndecan-1-depleted cells, which displayed increased filopodia formation. Conclusions: We conclude that syndecan-1 is a novel target of the oncomiR miR-10b. Rho-GTPase dependent modulation of cytoskeletal function and downregulation of E-cadherin expression are identified as relevant effectors of the miR-10b-syndecan-1 axis, which emerges as a promising target for the development of new therapeutic approaches for breast cancer.

Quantitative analysis of sulphated glycosaminoglycans content of Malaysian sea cucumber Stichopus hermanni and Stichopus vastus

Stichopus hermanni and Stichopus vastus are sea cucumber species from the Stichopodidae family within the coastal waters of Malaysia. The integument of these invertebrates is hypothesised to contain abundant glycosaminoglycans (GAGs). GAGs are divided into non-sulphated and sulphated GAGs. Sulphated GAGs have various chemico-biological functions that are beneficial to humans. This study quantitatively analysed N-, O-sulphated and total sulphated GAG content from three different anatomical regions (integument, internal organs and coelomic fluid) of S. hermanni and S. vastus. The integument revealed the highest content of total, O- and N-sulphated GAGs, followed by the internal organs and the coelomic fluid for both species of sea cucumbers. The percentage division of O- and N-sulphated GAGs suggested that anatomical parts of both species showed higher levels of O-sulphated GAGs compared to N-sulphated GAGs. In conclusion, these findings indicate that the integument body wall of S. hermanni and S. vastus is a rich source of sulphated GAGs.

Transcriptome profiling of murine spinal neurulation using laser capture microdissection and high-density oligonucleotide microarrays

Neurulation is a critical process in the formation of the central nervous system during embryonic -development. Closure of the neural tube is driven by forces that originate from both the neuroepithelium and the surrounding tissues. In this chapter, we describe the use of laser capture microdissection to -isolate and separately collect cells from the neuroepithelium and the underlying mesenchyme. We provide protocols for processing of samples for downstream comparison of the transcriptomes of two cell populations using high-density oligonucleotide microarrays, with an emphasis on important technical issues that are to be borne in mind when carrying out these experiments.

High origin of radial arteries: a report of two rare cases

Variations in the arterial supply of the upper limb are relatively common, with reported prevalence rates ranging from 11 to 24.4%. Of these, the most commonly encountered variation in the arm is a high origin of the radial artery. However, after consecutively dissecting and examining 600 Singaporean Chinese cadavers (1,200 upper limbs), we found only two cases of this. In both cases, the brachioradial artery originated from the upper one-third of the brachial artery and continued distally as the radial artery in the forearm. The local prevalence of 0.33% of this variation is significantly lower compared against populations from other geographical regions. Although rare, recognition of the variation is of fundamental importance to clinical practice.

miR-145-dependent targeting of junctional adhesion molecule A and modulation of fascin expression are associated with reduced breast cancer cell motility and invasiveness

Micro RNAs are small non-coding RNAs, which regulate fundamental cellular and developmental processes at the transcriptional and translational level. In breast cancer, miR-145 expression is downregulated compared with healthy control tissue. As several predicted targets of miR-145 potentially regulate cell motility, we aimed at investigating a potential role for miR-145 in breast cancer cell motility and invasiveness. Assisted by Affymetrix array technology, we demonstrate that overexpression of miR-145 in MDA-MB-231, MCF-7, MDA-MB-468 and SK-BR-3 breast cancer cells and in Ishikawa endometrial carcinoma cells leads to a downregulation of the cell-cell adhesion protein JAM-A and of the actin bundling protein fascin. Moreover, podocalyxin and Serpin E1 mRNA levels were downregulated, and gamma-actin, transgelin and MYL9 were upregulated upon miR-145 overexpression. These miR-145-dependent expression changes drastically decreased cancer cell motility, as revealed by time-lapse video microscopy, scratch wound closure assays and matrigel invasion assays. Immunofluorescence microscopy demonstrated restructuring of the actin cytoskeleton and a change in cell morphology by miR-145 overexpression, resulting in a more cortical actin distribution, and reduced actin stress fiber and filopodia formation. Nuclear rotation was observed in 10% of the pre-miR-145 transfected MDA-MB-231 cells, accompanied by a reduction of perinuclear actin. Luciferase activation assays confirmed direct miR-145-dependent regulation of the 3'UTR of JAM-A, whereas siRNA-mediated knockdown of JAM-A expression resulted in decreased motility and invasiveness of MDA-MB-231 and MCF-7 breast cancer cells. Our data identify JAM-A and fascin as novel targets of miR-145, firmly establishing a role for miR-145 in modulating breast cancer cell motility. Our data provide a rationale for future miR-145-targeted approaches of antimetastatic cancer therapy.

Function of sirtuins in biological tissues

Sirtuins are protein deacetylases, which are dependent on nicotine adenine dinucleotide. They are phylogenetically conserved from bacteria to humans. Seven sirtuin proteins localized in a wide variety of subcellular locations have been identified in the human genome. The most important known function of sirtuins is their regulation of transcriptional repression, mediated through binding of a complex containing sirtuins and other proteins. Studies have shown that sirtuins have pathophysiological relevance to neurodegeneration, muscle differentiation, inflammation, obesity, and cancer. In addition, sirtuin activity extends the lifespan of several organisms. In this review, we discuss the mode(s) of action of sirtuins, and their biological role(s) in health and disease.

Expression of syndecan-2 in the amoeboid microglial cells and its involvement in inflammation in the hypoxic developing brain

The present study examined the expression of heparan sulphate proteoglycan, syndecan-2 (Sdc-2) in the corpus callosum and the amoeboid microglial cells (AMC) in the neonatal rat brain in response to hypoxia. In 1-day old Wistar rats subjected to hypoxia the mRNA and protein expression of Sdc-2 in the corpus callosum, heavily populated by AMC, was increased up to 3 days after the hypoxic exposure. Immunoexpression of Sdc-2 was localized in AMC as confirmed by double labeling using microglial marker. Primary cultures of microglial cells subjected to hypoxia showed a significant increase in Sdc-2 expression. Application of Sdc-2 to microglial cultures under hypoxia increased the release of tumor necrosis factor-alpha, interleukin-1beta, chemokine (C-C motif) ligand 2 (CCL2), and chemokine (C-X-C motif) ligand 12 (CXCL12) by the microglial cells. Additionally, Sdc-2 enhanced the production of reactive oxygen species (ROS) by microglia subjected to hypoxia. Edaravone [3-methyl-1phenyl-2-pyrazolin-5-one], an antioxidant drug, suppressed the hypoxia- and Sdc-2-induced increased production of cytokines, chemokines, and ROS. In the light of these findings, we suggest that Sdc-2 plays an important role in microglial production of inflammatory cytokines, chemokines, and ROS in hypoxic conditions. In this connection, edaravone suppressed the hypoxia- and Sdc-2-induced increased cytokine and ROS production suggesting its therapeutic potential in ameliorating neuroinflammation.

Differential roles for membrane-bound and soluble syndecan-1 (CD138) in breast cancer progression

The heparan sulfate proteoglycan syndecan-1 (Sdc1) modulates cell proliferation, adhesion, migration and angiogenesis. Proteinase-mediated shedding converts Sdc1 from a membrane-bound coreceptor into a soluble effector capable of binding the same ligands. In breast carcinomas, Sdc1 overexpression correlates with poor prognosis and an aggressive phenotype. To distinguish between the roles of membrane-bound and shed forms of Sdc1 in breast cancer progression, human MCF-7 breast cancer cells were stably transfected with plasmids overexpressing wild-type (WT), constitutively shed and uncleavable forms of Sdc1. Overexpression of WT Sdc1 increased cell proliferation, whereas overexpression of constitutively shed Sdc1 decreased proliferation. Fibroblast growth factor-2-mediated mitogen-activated protein kinase signaling was reduced following small-interfering RNA (siRNA)-mediated knockdown of Sdc1 expression. Constitutively, membrane-bound Sdc1 inhibited invasiveness, whereas soluble Sdc1 promoted invasion of MCF-7 cells into matrigel matrices. The latter effect was reversed by the matrix metalloproteinase inhibitors N-isobutyl-N-(4-methoxyphenylsufonyl) glycyl hydroxamic acid and tissue inhibitor of metalloproteinase (TIMP)-1. Affymetrix microarray analysis identified TIMP-1, Furin and urokinase-type plasminogen activator receptor as genes differentially regulated in soluble Sdc1-overexpressing cells. Endogenous TIMP-1 expression was reduced in cells overexpressing soluble Sdc1 and increased in those overexpressing the constitutively membrane-bound Sdc1. Moreover, E-cadherin protein expression was downregulated in cells overexpressing soluble Sdc1. Our results suggest that the soluble and membrane-bound forms of Sdc1 play different roles at different stages of breast cancer progression. Proteolytic conversion of Sdc1 from a membrane-bound into a soluble molecule marks a switch from a proliferative to an invasive phenotype, with implications for breast cancer diagnostics and potential glycosaminoglycan-based therapies.

Changes in heparan sulfate are associated with delayed wound repair, altered cell migration, adhesion and contractility in the galactosyltransferase I (beta4GalT-7) deficient form of Ehlers-Danlos syndrome

Reduced activity of beta4-galactosyltransferase 7 (beta4GalT-7), an enzyme involved in synthesizing the glycosaminoglycan linkage region of proteoglycans, is associated with the progeroid form of Ehlers-Danlos syndrome (EDS). In the invertebrates Drosophila melanogaster and Caenorhabditis elegans, mutations in beta4GalT-7 affect biosynthesis of heparan sulfate (HS), a modulator of several biological processes relevant to wound repair. We have analyzed structural alterations of HS and their functional consequences in human beta4GalT-7 Arg270Cys mutant EDS and control fibroblasts. HS disaccharide analysis by reversed phase ion-pairing chromatography revealed a reduced sulfation degree of HS paralleled by altered immunostaining patterns for the phage-display anti-HS antibodies HS4E4 and RB4EA12 in beta4GalT-7 mutant fibroblasts. Real-time PCR-analysis of 44 genes involved in glycosaminoglycan biosynthesis indicated that the structural alterations in HS were not caused by differential regulation at the transcriptional level. Scratch wound closure was delayed in beta4GalT-7-deficient cells, which could be mimicked by enzymatic removal of HS in control cells. siRNA-mediated knockdown of beta4GalT-7 expression induced morphological changes in control fibroblasts which suggested altered cell-matrix interactions. Adhesion of beta4GalT-7 deficient cells to fibronectin was increased while actin stress fiber formation was impaired relative to control cells. Also collagen gel contraction was delayed in the beta4GalT-7 mutants which showed a reduced formation of pseudopodia and filopodia, less efficient penetration of the collagen gels and a diminished formation of collagen suprastructures. Our study suggests an HS-dependent basic mechanism behind the altered wound repair phenotype of beta4GalT-7-deficient EDS patients.

Comparison of the effects of differentially sulphated bovine kidney- and porcine intestine-derived heparan sulphate on breast carcinoma cellular behaviour

Heparan sulphate is a sulphated glycosaminoglycan and is able to bind to and regulate the activity of many growth and signalling factors. We have previously shown that its expression is correlated with tumour grade and cell proliferation in breast phyllodes tumours. In this study, we examined the use of heparan sulphate as a biomarker of invasive ductal carcinoma and the effects of differentially sulphated heparan species on breast cancer cell behaviour. Immunohistochemistry using the 10E4 monoclonal antibody was carried out on 32 paraffin-embedded breast cancer specimens and paired non-cancerous breast tissues to compare the expression patterns of heparan sulphate. Upregulated expression of the sulphated 10E4 epitope in heparan sulphate was detected in both epithelial and stromal compartments of breast cancer compared with normal mammary tissues, with a 2.8X increase in immunoreactivity score. To determine the effects of differentially sulphated heparan sulphate molecules on breast cancer behaviour, cultured breast carcinoma cells were treated with chlorate, a competitive inhibitor of glycosaminoglycan sulphation, and two different heparan sulphate species. Inhibition of glycosaminoglycan sulphation resulted in a significant increase in cancer cell adhesion and a reduction in cell migration, together with upregulated expression of focal adhesion kinase and paxillin. Both porcine intestine- and bovine kidney-derived heparan sulphate species could block the change in cell adhesion. However, the former heparan sulphate species completely abolished, while the latter exacerbated, the chlorate-induced decrease in cell migration. The results show that heparan sulphate is a useful biomarker of breast invasive ductal carcinoma. Different sulphation patterns of heparan sulphate residues have differential effects in regulating breast cancer cellular behaviour, and this may be exploited to develop heparan sulphate into a useful target for treatment of breast carcinoma.

Synthesis, characterization and evaluation of benzimidazole derivative and its precursors as inhibitors of MDA-MB-231 human breast cancer cell proliferation

A novel series of trisubstituted benzimidazole and its precursors (3-7) were synthesised and characterized by using 1H NMR, LC/MS, FTIR and elemental analysis techniques. The title compounds were evaluated for inhibition against MDA-MB-231 breast cancer cell proliferation. The results revealed that the compound N-(4-cyano-3-(trifluoromethyl) phenyl)-4-fluoro-3-nitrobenzamide (3) was the potent inhibitor.

Endothelin receptor type B counteracts tenascin-C-induced endothelin receptor type A-dependent focal adhesion and actin stress fiber disorganization

Tenascin-C, an extracellular matrix molecule of the tumor-specific microenvironment, counteracts the tumor cell proliferation-suppressing effect of fibronectin by blocking the integrin alpha(5)beta(1)/syndecan-4 complex. This causes cell rounding and stimulates tumor cell proliferation. Tenascin-C also stimulates endothelin receptor type A (EDNRA) expression. Here, we investigated whether signaling through endothelin receptors affects tenascin-C-induced cell rounding. We observed that endothelin receptor type B (EDNRB) activation inhibited cell rounding by tenascin-C and induced spreading by restoring expression and function of focal adhesion kinase (FAK), paxillin, RhoA, and tropomyosin-1 (TM1) via activation of epidermal growth factor receptor, phospholipase C, c-Jun NH(2)-terminal kinase, and the phosphatidylinositol 3-kinase pathway. In contrast to EDNRB, signaling through EDNRA induced cell rounding, which correlated with FAK inhibition and TM1 and RhoA protein destabilization in the presence of tenascin-C. This occurred in a mitogen-activated protein kinase/extracellular signal-regulated kinase kinase-dependent manner. Thus, tumorigenesis might be enhanced by tenascin-C involving EDNRA signaling. Inhibition of tenascin-C in combination with blocking both endothelin receptors could present a strategy for sensitization of cancer and endothelial cells toward anoikis.

On the role of endothelin-converting enzyme-1 (ECE-1) and neprilysin in human breast cancer

Endothelin-1 (ET-1) and its receptors, ET(A)R and ET(B)R, are overexpressed in breast carcinomas. However, little is known about the relevance of endothelin-converting enzyme-1 (ECE-1) and ET-1 degrading neprilysin (NEP). In this study, expression of ECE-1 and NEP was determined in 600 breast cancer tissue samples by immunohistochemistry; staining results were correlated with clinicopathological parameters. For ECE-1 expression, we found a significant correlation with VEGF (P < 0.001) and ET(A)R expression (P = 0.048). While patients with ECE-1 overexpressing tumours had more frequent disease recurrence (P = 0.03), NEP overexpression correlated with improved disease-free survival (DFS) (P = 0.023) and less frequent metastasis (P = 0.046). Also, a decrease of NEP expression with malignant progression (G1-G3) was found. ECE-1 inhibition using the selective ECE-1 inhibitor RO 67-7447 in MCF-7 breast cancer cells led to a significantly decreased ET-1 expression and reduced cell invasiveness (54.3% of controls, P = 0.014). Our results indicate that overexpression of ECE-1 is associated with unfavourable outcome, whereas NEP positively influences survival. Thus, expression of ECE-1 and NEP may have prognostic relevance. Due to the anti-invasive effect of the selective ECE-1 inhibitor, targeting ECE-1 may represent an innovative option in future breast cancer therapy.

Therapeutic value of glycosaminoglycans in cancer

Glycosaminoglycans are unbranched polysaccharides composed of repeating units of alternating uronic acids and amino sugars. Most glycosaminoglycans are covalently attached to core proteins to form proteoglycans. Posttranslational modifications result in specific motifs that bind to a large variety of ligands, thus regulating growth factor signaling, cellular behavior, inflammation, angiogenesis, and the proteolytic environment. Dysregulated expression of glycosaminoglycans is present in cancer and reported to correlate with clinical prognosis in several malignant neoplasms. Recent knowledge on the biological roles of these molecules in cancer biology, tumor angiogenesis, and metastasis has promoted the development of drugs targeting them. Pharmaceutical approaches include the use of chemically modified heparins and glycosaminoglycans with defined structures, combination of inhibitors of glycosaminoglycan biosynthesis and polyamine depletion, and biologically active glycosaminoglycan-binding peptides. In addition, glycosaminoglycans are used as tumor-specific delivery and targeting vehicles for toxins and chemotherapeutics. Encouraging results in animal studies and clinical trials show the clinical relevance of glycosaminoglycan-based drugs and the use of glycosaminoglycans as therapeutic targets.

Heparanase, hyaluronan, and CD44 in cancers: a breast carcinoma perspective

Glycosaminoglycans are major constituents of the cancer cell surface and the tumor stroma. The heparan sulfate degrading enzyme heparanase, hyaluronan, and its receptor CD44 are up-regulated in breast cancer, generating a microenvironment that promotes tumor progression and metastasis. Recent experimental and clinical evidence shows that heparanase, hyaluronan, and CD44 regulate cancer cell proliferation, migration, and invasion, as well as tumor-associated angiogenesis and are correlated with patient survival. These findings suggest that they may be used as prognostic factors and targets for breast cancer treatment.

Defective glycosylation of decorin and biglycan, altered collagen structure, and abnormal phenotype of the skin fibroblasts of an Ehlers–Danlos syndrome patient carrying the novel Arg270Cys substitution in galactosyltransferase I (β4GalT-7)

The Ehlers-Danlos syndrome (EDS) is a heterogeneous group of connective tissue disorders affecting skin and joint function. Molecular defects in extracellular matrix proteins, including collagen (type I, III, and V) and tenascin X are associated with different forms of EDS. Compound heterozygous mutations in the B4GALT7 gene, resulting in aberrant glycosylation of the dermatan sulfate proteoglycan decorin, had been described in a single patient affected with the progeroid form of EDS. We have studied the molecular phenotype of decorin, biglycan, and collagen type I containing fibrils in skin fibroblasts of a patient carrying the novel homozygous C808T point mutation in the B4GALT7 gene, which causes an Arg270Cys substitution in beta4GalT-7. Compared to control fibroblasts, galactosyltransferase activity in beta4GalT-7(Arg270Cys) cells was approximately three times reduced over a temperature range of 25-41 degrees C. Pulse-chase experiments and confocal microscopy demonstrated that synthesis and secretion of decorin were normal in beta4GalT-7(Arg270Cys) cells. However, about 50% of decorin were synthesized as a protein core in addition to its proteoglycan form. Biglycan was found in a monoglycanated form in addition to its mature form. Glycosaminoglycan chains were of the dermatan/chondroitin sulfate type both in beta4GalT-7(Arg270Cys) and control cells, and epimerization was reduced for decorin and biglycan. Compared to control cells, beta4GalT-7(Arg270Cys) cells showed altered, highly spread or stretched phenotypes and decreased proliferation rates. At the ultrastructural level, an intracellular accumulation of multiple secondary lysosomes and degenerative vacuoles was seen in beta4GalT-7(Arg270Cys) cells. Furthermore, the collagen suprastructures were altered in the beta4GalT-7(Arg270Cys) cells. The reduced beta4GalT-7 activity resulting in defective glycosylation of decorin and biglycan may be responsible for the complex molecular pathology in beta4GalT-7 deficient EDS patients, given the role of these proteoglycans in bone formation, collagen fibrillogenesis, and skeletal muscle development.