Heparanase enzyme in chronic inflammatory bowel disease and colon cancer

Heparanase is the sole mammalian endoglycosidase that cleaves heparan sulfate, the key polysaccharide of the extracellular matrix and basement membranes. Enzymatic cleavage of heparan sulfate profoundly affects a variety of physiological and pathological processes, including morphogenesis, neovascularization, inflammation, and tumorigenesis. Critical involvement of heparanase in colorectal tumor progression and metastatic spread is widely documented; however, until recently a role for heparanase in the initiation of colon carcinoma remained underappreciated. Interestingly, the emerging data that link heparanase to chronic inflammatory bowel conditions, also suggest contribution of the enzyme to colonic tumor initiation, at least in the setting of colitis-associated cancer. Highly coordinated interplay between intestinal heparanase and immune cells (i.e., macrophages) preserves chronic inflammatory conditions and creates a tumor-promoting microenvironment. Here we review the action of heparanase in colon tumorigenesis and discuss recent findings, pointing to a role for heparanase in sustaining immune cell-epithelial crosstalk that underlies intestinal inflammation and the associated cancer.     

Heparanase involvement in physiology and disease

Heparanase is an endoglycosidase that degrades heparan sulfate on the cell surface and extracellular matrix. The physiological functions of heparanase include heparan sulfate turnover, embryo development, hair growth, and wound healing. Heparanase is implicated in a variety of pathologies, such as tumor growth, angiogenesis, metastasis, inflammation, and glomerular diseases. Heparanase overexpression in a variety of malignant tumors suggests that it could be a target for anti-cancer therapy.     

Processing of heparanase is mediated by syndecan-1 cytoplasmic domain and involves syntenin and α-actinin

Heparanase activity plays a decisive role in cell dissemination associated with cancer metastasis. Cellular uptake of heparanase is considered a pre-requisite for the delivery of latent 65-kDa heparanase to lysosomes and its subsequent proteolytic processing and activation into 8- and 50-kDa protein subunits by cathepsin L. Heparan sulfate proteoglycans, and particularly syndecan, are instrumental for heparanase uptake and activation, through a process that has been shown to occur independent of rafts. Nevertheless, the molecular mechanism underlying syndecan-mediated internalization outside of rafts is unclear. Here, we examined the role of syndecan-1 cytoplasmic domain in heparanase processing, utilizing deletion constructs lacking the entire cytoplasmic domain (Delta), the conserved (C1 or C2), or variable (V) regions. Heparanase processing was markedly increased following syndecan-1 over-expression; in contrast, heparanase was retained at the cell membrane and its processing was impaired in cells over-expressing syndecan-1 deleted for the entire cytoplasmic tail. We have next revealed that conserved domain 2 (C2) and variable (V) regions of syndecan-1 cytoplasmic tail mediate heparanase processing. Furthermore, we found that syntenin, known to interact with syndecan C2 domain, and α actinin are essential for heparanase processing.     

Impaired nuclear translocation of glucocorticoid receptors: novel findings from psoriatic epidermal keratinocytes

Psoriasis is a chronic proliferative skin disease and is usually treated with topical glucocorticoids, which act through the glucocorticoid receptor (GR), a component of the physiological systems essential for immune responses, differentiation, and homeostasis. To investigate the possible role of GR in the pathogenesis of psoriasis, normal and psoriatic lesional skin were recruited. Firstly, the immunolocalization of GR in the skin and cultured epidermal keratinocytes were determined by immunofluorescence. In normal skin and cultured human epidermal keratinocytes, intracellular GR is localized in the nuclei, while in psoriatic skin and cultured keratinocytes, GR is in the cytoplasm. Next, we investigated possible factors associated with the cytoplasmic distribution. We found that VEGF and IFN-γ led to impaired nuclear translocation of GR through p53 and microtubule-inhibitor, vincristine, and inhibited nuclear uptake of GR in normal keratinocytes. In addition to dexamethasone, interleukin (IL)-13 was also able to transfer GR into nuclei of psoriatic keratinocytes. Furthermore, discontinuation of dexamethasone induced cytoplasmic retention of GR in normal keratinocytes. In contrast, energy depletion of normal epidermal keratinocytes did not change the nuclear distribution of GR. To confirm our findings in vivo, an imiquimod-induced psoriasis-like skin mouse model was included. IL-13 ameliorated (but vincristine exacerbated) the skin lesions on the mouse. Taken together, our findings define that impaired nuclear translocation of GR is associated with VEGF, IFN-γ, p53, and microtubule. Therapeutic strategies designed to accumulate GR in the nucleus, such as IL-13, may be beneficial for the therapy of psoriasis.     

Functions of skin-resident γδ T cells

The murine epidermis contains resident T cells that express a canonical γδ TCR and arise from fetal thymic precursors. These cells are termed dendritic epidermal T cells (DETC) and use a TCR that is restricted to the skin in adult animals. DETC produce low levels of cytokines and growth factors that contribute to epidermal homeostasis. Upon activation, DETC can secrete large amounts of inflammatory molecules which participate in the communication between DETC, neighboring keratinocytes and langerhans cells. Chemokines produced by DETC may recruit inflammatory cells to the epidermis. In addition, cell–cell mediated immune responses also appear important for epidermal–T cell communication. Information is provided which supports a crucial role for DETC in inflammation, wound healing, and tumor surveillance.     

The obesity-related pathology and Th17 cells

Chronic inflammation associated with obesity plays a major role in the development of metabolic diseases, cancer, and autoimmune diseases. Among Th subsets, Th17 cells are involved in the pathogenesis of autoimmune disorders such as psoriasis, rheumatoid arthritis, inflammatory bowel disease, steroid-resistant asthma, and multiple sclerosis. Accumulating data suggest that reciprocal interactions between the metabolic systems and immune system play pivotal roles in the pathogenesis of obesity-associated diseases. We herein outline the developing principles in the control of T cell differentiation and function via their cellular metabolism. Also discussed are recent findings that changes in the intracellular metabolism, including fatty acid metabolism, affect the Th17 cell function in obese individuals. Finally, we will also highlight the unique molecular mechanism involved in the activation of retinoid-related orphan receptor-gamma-t (RORγt) by intracellular metabolism and discuss a new therapeutic approach for treating autoimmune disorders through the inhibition of RORγt.     

Infection of cultured intestinal epithelial cells with severe acute respiratory syndrome coronavirus

To identify a model for the study of intestinal pathogenesis of severe acute respiratory syndrome (SARS) we tested the sensitivity of six human intestinal epithelial cell lines to infection with SARS coronavirus (SARS-CoV). In permissive cell lines, effects of SARS-CoV on cellular gene expression were analysed using high-density oligonucleotide arrays. Caco-2 and CL-14 cell lines were found to be highly permissive to SARS-CoV, due to the presence of angiotensin-converting enzyme 2 as a functional receptor. In both cell lines, SARS-CoV infection deregulated expression of cellular genes which may be important for the intestinal pathogenesis of SARS.Received 23 May 2004; received after revision 23 June 2004; accepted 25 June 2004     

Galanin – 25 years with a multitalented neuropeptide

The skin, the largest organ of the body, functions as a barrier between the body proper and the external environment, as it is constantly exposed to noxious stressors. During the last few years, the concept of an interactive network involving cutaneous nerves, the neuroendocrine axis, and the immune system has emerged. The neuroendocrine system of the skin is composed of locally produced neuroendocrine mediators that interact with specific receptors. Among these mediators are neuropeptides, including members of the galanin peptide family--galanin, galanin-message-associated peptide, galanin-like peptide, and alarin--which are produced in neuronal as well as nonneuronal cells in the skin. Here we review the expression of the galanin peptides and their receptors in the skin, and the known functions of galanin peptides in different compartments of the skin. We discuss these data in light of the role of the galanin peptide family in inflammation and cell proliferation.     

Tumor suppressor role of protein 4.1B/DAL-1

Protein 4.1B/DAL-1 is a membrane skeletal protein that belongs to the protein 4.1 family. Protein 4.1B/DAL-1 is localized to sites of cell–cell contact and functions as an adapter protein, linking the plasma membrane to the cytoskeleton or associated cytoplasmic signaling effectors and facilitating their activities in various pathways. Protein 4.1B/DAL-1 is involved in various cytoskeleton-associated processes, such as cell motility and adhesion. Moreover, protein 4.1B/DAL-1 also plays a regulatory role in cell growth, differentiation, and the establishment of epithelial-like cell structures. Protein 4.1B/DAL-1 is normally expressed in multiple human tissues, but loss of its expression or prominent down-regulation of its expression is frequently observed in corresponding tumor tissues and tumor cell lines, suggesting that protein 4.1B/DAL-1 is involved in the molecular pathogenesis of these tumors and acts as a potential tumor suppressor. This review will focus on the structure of protein 4.1B/DAL-1, 4.1B/DAL-1-interacting molecules, 4.1B/DAL-1 inactivation and tumor progression, and anti-tumor activity of the 4.1B/DAL-1.     

Periostin in the pathogenesis of skin diseases

Skin is an organ that is susceptible to damage by external injury, chronic inflammation, and autoimmunity. Tissue damage causes alterations in both the configuration and type of cells in lesional skin. This phenomenon, called tissue remodeling, is a universal biological response elicited by programmed cell death, inflammation, immune disorders, and tumorigenic, tumor proliferative, and cytoreductive activity. In this process, changes in the components of the extracellular matrix are required to provide an environment that facilitates tissue remodeling. Among these extracellular matrix components, periostin, a glycoprotein that is predominantly secreted from dermal fibroblasts, has attracted attention. Periostin localizes in the papillary dermis of normal skin, and is aberrantly expressed in the dermis of lesional skin in atopic dermatitis, scar, systemic/limited scleroderma, melanoma, cutaneous T cell lymphoma, and skin damage caused by allergic/autoimmune responses. Periostin induces processes that result in the development of dermal fibrosis, and activate or protract the immune response. The aim of this review was to summarize recent knowledge of the role of periostin in the pathogenesis of dermatoses, and to explore whether periostin is a potential therapeutic target for skin diseases.     

UV guided dendritic growth patterns and the networking of melanocytes

Whole skin organ cultures of vitiliginous, skin show that the marginal melanocytes are highly sensitive to a pulse of UV exposure (210–380 nm) during the G₂ phase of the cell cycle, as seen by prominent dendricity. Melanocytes are highly dendritic in the epidermis overlying rapidly growing tumors, as well as within proliferative lesions such as basal cell carcinomas and aggressive seborrheic keratosis. In the organ cultures the dendrites extend towards the source of UV, i.e. the surface, while the main body lies along the basement membrane. The epidermal melanocytes overlying tumors lie, almost vertically, dendrites aligned towards the underlying tumor on one side and the surface on the other. Within tumors dendritic elongation is guided by mitotic and PCNA positive (S-phase) tumor cells, which are a source of ultraweak UV emissions in the range of 210–330 nm. These observations indicate that ultraweak biophoton emissions from neighbouring cells can simulate environmental cues and contribute to the plasticity of networks such as the melanocytes or the visual pathways.     

Merkel cell carcinoma

Merkel cell carcinoma (MCC) is a highly aggressive neuroendocrine carcinoma of the skin. More than one-third of MCC patients will die from this cancer, making it twice as lethal as malignant melanoma. Despite the fact that MCC is still a very rare tumor, its incidence is rapidly increasing; the American Cancer Society estimates for 2008 almost 1 500 new cases in the USA. These clinical observations are especially disturbing as the pathogenesis of MCC is not yet fully understood; however, a number of recent reports contribute to a better understanding of its pathogenesis. Here we describe findings regarding the role of Wnt, MAPK and Akt signaling as well as possible aberrations in the p14ARF/p53/RB tumor suppressor network in MCC. Most important, and possibly with high impact on future therapeutic approaches is the demonstration that a polyomavirus has frequently integrated in the genome of the MCC cells prior to tumor development. Received 12 August 2008; received after revision 06 October 2008; accepted 22 October 2008     

不同转移潜能乳腺癌细胞中EGFR的表达及意义

目的 研究表皮生长因子受体（epidermal growth factor receptor,EGFR）在不同转移潜能乳腺癌细胞中的表达,并探讨其在乳腺癌侵袭转移过程中的作用. 方法 利用人工基质膜侵袭实验获得高、低转移潜能乳腺癌细胞亚系,四甲基偶氮唑盐（MTT）法检测两系细胞生长曲线和倍增时间,流式细胞仪检测两系细胞周期,transwell侵袭小室模型比较两系的迁移能力.应用逆转录聚合酶链反应（RT-PCR）和免疫印迹（Western Blot）检测EGFR在两系细胞中的表达. 结果 利用transwell小室成功筛选出高、低转移潜能乳腺癌细胞亚系;它们的体外生长速度、倍增时间、细胞周期和侵袭力具有明显差异;RT-PCR和Western Blot均显示在高转移潜能乳腺癌细胞中EGFR在基因和蛋白水平的表达均显著高于低转移乳腺癌细胞. 结论 EGFR的过表达与乳腺癌细胞侵袭能力显著性相关,EGFR在乳腺癌侵袭过程中发挥了重要的作用.     

Stable lipid peroxidation products in human skin: detection,ultraviolet light-induced increase,pathogenic importance

Summary Products of lipid peroxidation (malonaldehyde, Schiff-bases) were detected in human skin. These products were increased after UV-light exposition, on chronically sun-exposed areas as well as with advancing age. Malonaldehyde cross linked epidermal glucose-6-phosphate-dehydrogenase and diminished their activity.We wish to acknowledge the support and encourgement of Dr.W. E. Höhne, Institute of Physiological and Biological Chemistry, Humboldt University Berlin.