Towards dissecting molecular routes of intercellular communication in the tumour microenvironment: phenotypic plasticity of stem cell-associated markers in co-culture (carcinoma cell/fibroblast) systems.

Increasing evidence attributes tumour fates to a small population of cells (cancer stem cells) capable of surviving therapeutic interventions. Investigation of their characteristics, especially in cross-talk with other cell types of the tumour microenvironment, can pave the way to innovative therapeutic concepts. The central issue of this study was to evaluate the impact of stroma on tumour cells with stem cell-like features in a squamous cell carcinoma model (FaDu). Six different types of experimental conditions were tested using distinct compositions of the culture system, and both morphologic and molecular features of the tumour cells were analysed. In detail, FaDu cells alone were used as a control, compared to tumour cells from co-culture, with squamous cell cancer-derived stromal fibroblasts or normal skin human fibroblasts, both in the direct and indirect (insert) systems, adding analysis of side population cells of FaDu culture. Measurements were taken on days 2, 7 and 9 of culture and immediately after preparation in the case of the side population. A panel of antibodies against keratins 8, 10, 19, stem cell markers CD29, CD44, CD133, as well as biotinylated adhesion/growth-regulatory galectin 1 served as a toolbox for phenotypic characterization. Co-culture with fibroblasts prepared from tumour stroma and with dermal fibroblasts affected marker presentation, maintaining an undifferentiated stage phenotypically related to stem cells. Side-population cells showed close relationship to cancer stem cells in these characteristics. In conclusion, normal and tumour stromal fibroblasts are capable of shifting the marker expression profile of FaDu cells to a stem cell-like phenotypic pattern in co-culture.

Phylogeny, regeneration, ageing and cancer: role of microenvironment and possibility of its therapeutic manipulation.

Data about the possible correlation between reduction of the regeneration capacity in the course of phylogeny and formation of malignant tumours have been summarized from invertebrates to mammals. The evolutionarily increasing complexity of body building plane and expectancy of longevity in the course of phylogeny seems to be grossly negatively correlated with diminished regeneration capacity, but positively with increased occurrence of malignant tumours. A certain evolution-based switch-off mechanism reducing the extent of regeneration in developmentally complicated and long-living animals such as mammals and birds can be hypothesized and benefits of loss of this ability are discussed. This high incidence of malignancies seems to be related, in addition to other factors, to prolonged and cumulative exposure to cancerogenic stimuli in the course of lifetime. Longevity, supported by the progress and availability of medical care to the population, has been unveiling this phenomenon during recent decades. From this point of view, ageing represents the main risk for cancer acquisition. The probable role of microenvironment in all the discussed phenomena such as healing/regeneration, inflammation, and cancer is discussed and targeting of microenvironment is consequently predicted as a possible therapeutic target where controlled manipulation may represent a new approach to the treatment of cancer patients.

Comparative analysis of IL-8 and CXCL-1 production by normal and cancer stromal fibroblasts.

It has been shown that fibroblasts within the stroma of malignant tumours can affect the tumour's biological character, influencing such properties as local aggressiveness and metastasis potential. This influence is asserted via paracrine secretion of multiple cell factors, including chemokines. This study demonstrates that both normal keratinocytes and cancer cells can stimulate the secretion of chemokines IL-8 and CXCL-1 from normal dermal fibroblasts and stromal fibroblasts from squamous cell carcinoma. The effect of epithelia on normal fibroblasts leads to a transient secretory change, in contrast to stromal fibroblasts which generate a more prolonged one. This observation demonstrates that stimulated expression of both IL-8 and CXCL-1 is not specific to cancer, supporting the hypothesis that similar mechanisms exist between wound healing and oncogenesis. It also shows that stromal fibroblasts isolated from a tumour have significantly different features from normal fibroblasts.

Fibroblasts prepared from different types of malignant tumors stimulate expression of luminal marker keratin 8 in the EM-G3 breast cancer cell line.

It is widely recognized that stromal fibroblasts significantly influence biological properties of multiple tumors including breast cancer. However, these epithelial-mesenchymal interactions seem to be essential in tumor biology and it is not fully clear whether this interaction is tumor type-specific or has a more general non-specific character. To elucidate this question, we tested the effect of cancer-associated fibroblasts (CAFs) isolated from different types of tumors (breast cancer skin metastasis, cutaneous basal cell carcinoma and melanoma, squamous cell carcinoma arising from oral cavity mucous membrane) on the EM-G3 breast cancer cell line. The results were compared with control experiments using normal human dermal fibroblasts, 3T3 mouse fibroblasts, and 3T3 fibroblasts influenced by the fibroblasts prepared from the basal cell carcinoma. Our results demonstrated that expression of luminal marker keratin 8 was influenced only by CAFs prepared from any tested tumors. In contrast, all tested types of fibroblasts showed a strong stimulatory effect on the expression of basal/myoepithelial marker keratin 14. The CAFs also elevated the number of cells with positivity for both keratins 8 and 14 that are similar to ductal originated precursor cells. The expression of proliferation marker Ki67 was not influenced by any of the tested fibroblasts. In conclusion, our data indicate that CAFs are able to influence the phenotype of a breast cancer cell line and this effect is based on a tumor type-unspecific mechanism. Finally, a clear functional difference between normal and CAFs was demonstrated.

Comparative analysis of the nuclear presence of adhesion/growth-regulatory galectins and reactivity in the nuclei of interphasic and mitotic cells.

Nuclear galectins participate in splicing of pre-mRNA. In this study we detected galectins-1, -2, -3 and -7 and their glycoligands in three types of cells: fibroblasts, cancer epithelial cells and melanoma cells. The results demonstrated that the nuclear expression of distinct types of galectins and their ligands in interphasic nuclei is dependent on the cell type. The extensive binding of labelled galectins-1 and -2 to mitotic cells (around chromosomes, in mitotic spindle and in bridge connecting both daughter cells) suggests their role during the cell division.

Genistein does not inhibit TGF-beta1-induced conversion of human dermal fibroblasts to myofibroblasts.

Transforming growth factor beta 1 (TGF-beta1) is a pro-fibrotic cytokine with a key role in wound repair and regeneration, including induction of fibroblast-to-myofibroblast transition. Genistein is a naturally occurring selective estrogen receptor modulator with promising anti-fibrotic properties. In the present study we aimed to investigate whether genistein modulates TGF-beta1 (canonical and non-canonical) signaling in normal dermal fibroblasts at the protein level (Western blot and immunofluorescence). We demonstrated that TGF-beta1 induces the myofibroblast-like phenotype in the studied fibroblast signaling via canonical (SMAD) and non-canonical (AKT, ERK1/2, ROCK) pathways. Genistein induced only ERK1/2 expression, whereas the combination of TGF-beta1 and genistein attenuated the ERK1/2 and ROCK signaling. Of note, the other studied pathways remained almost unaffected. From this point of view, genistein does not impair conversion of normal fibroblasts to myofibroblast-like cells.

Differential regulation of galectin expression/reactivity during wound healing in porcine skin and in cultures of epidermal cells with functional impact on migration.

The glycophenotyping of mammalian cells with plant lectins maps aspects of the glycomic profile and disease-associated alterations. A salient step toward delineating their functional dimension is the detection of endogenous lectins. They can translate sugar-encoded changes into cellular responses. Among them, the members of the lectin family of galectins are emerging regulators of cell adhesion, migration and proliferation. Focusing on galectins-1, -3 and -7, we addressed the issue whether their expression is regulated during wound healing in porcine skin as model. A conspicuous upregulation is detected for galectin-1 in the dermis and a neoexpression in the epidermis, where an increased level of galectin-7 was also found. Applying biotinylated tissue lectins as probes, the signal intensities for accessible binding sites decreased, intimating an interaction of the cell lectin with reactive sites. In contrast, galectin-3 parameters remained rather constant. Of note, epidermal cells in culture also showed an increase in expression/presence of galectin-1, measured on the levels of mRNA and protein, in this case by Western blotting and quantitative immunocytochemistry. Used as matrix, galectin-1 conferred resistance to trypsin treatment to attached human keratinocytes and reduced migration into scratch-wound areas in vitro. This report thus presents new information on endogenous lectins in wound healing and differential regulation among the three tested cases.

Influence of hydroxyapatite crystallinity on the growth of keratinocytes.

Dental implantology is a field, which has made a great progression recently. The main task nowadays is to shorten the healing period and so improve the comfort for the patients. One possibility how to full fil this task is to coat the surface of the implant. Very promising material seems to be hydroxyapatite, which is a natural component of human body and suitable method is the pulsed laser deposition. In our study we tried to evaluate difference between crystalline and amorphous hydroxyapatite coated dental implants from the biological point of view. We found that the cells were able to adhere to all of our studied samples. The worst proliferation of fibroblasts was found on the amorphous coating, whereas the adhesion was fully comparable with other surfaces. The level of keratinocyte differentiation was the same on both of the studied surfaces.

[Galectins in squamous cell carcinomas of the head and neck cancers]. / Galektiny v dlazdicových karcinomech hlavy a krku.

Cancers of head and neck represents about 5% of all tumors. 80 to 90% of these tumors are constituted of squamous cell carcinomas. Despite a rapid progress in diagnostics and therapy the overall 5-year survival of this type of cancer is among the lowest of the major cancer types. This unfavourable situation needs the extensive research to found new markers to better characterize biological behavior of tumors as a rational background for more sophisticated therapeutic modalities. Among the most promising markers are endogenous lectins called galectins and their ligands. Especially galectin-1, -3 and -7 play a key role in pathology of squamous cell carcinomas.

Porcine epidermal stem cells as a biomedical model for wound healing and normal/malignant epithelial cell propagation.

This article summarizes research using cells derived from epidermis of the miniature pigs for use as a cell therapy for skin repair and as a model for squamous carcinoma of the head and neck. Stem cells are an important "tool" for biomedical research. Adult stem cells are defined functionally, as cells that have the capacity to self-renew as well as the ability to generate differentiated cells. They are present in defined tissue microenvironments called niches. Asymmetric mitosis allows them to produce one daughter cell with the properties of stem cells (self-renewal) and a second cell with characteristics of progenitor cells, or transit amplifying cells, which proliferate quickly but with a limited number of mitotic divisions. Porcine epidermal stem cells, located in the bulge region of the outer root sheath of hair follicles, migrate in vitro from hair sheaths and because they are resistant to anoikis (detachment induced apoptosis), survive in non-adhesive conditions to form spheroids. These cells express keratins, galectin-1 and their nuclei are rich in DeltaNp63alpha. Interestingly, the multiple phenotype analysis of the human tumor cells in squamous carcinoma of head and neck revealed similarities with epidermal stem cells. These cancer stem cells are usually located on the periphery of the tumor where the invasive front of the tumor responsible for its aggressive behavior is located. In contrast, extensive expression of markers of terminal differentiation such as expression of glycoligands reactive for the endogenous lectin, galectin-3, indicates better tumor prognosis.

Coexpression of binding sites for A(B) histo-blood group trisaccharides with galectin-3 and Lag antigen in human Langerhans cells.

Galectin-3 is an immunomodulatory protein with binding capacity for various glycoconjugates including IgE. It has been shown to be produced by epidermal keratinocytes and is present on the surfaces of skin Langerhans cells (LC). Therefore, it may have a role in the pathogenesis of various skin diseases, such as atopic dermatitis. To study the expression of galectin-3 in LC, we used, in addition to specific antibodies, a panel of synthetic, carrier-immobilized, specific oligosaccharides of the A- and B-histo-blood group, which are recognized by this lectin. In the mean time, Birbeck granules were visualized with an anti-Lag antibody. The double labeling experiments showed a remarkable colocalization of signals for Lag antigen (Birbeck granules) and galectin-3, as well as the binding sites for A- and B-histo-blood group trisaccharides. The specificity of the oligosaccharide binding was demonstrated by the lack of binding by Le(c), Le(d) (H blood group antigen), and sLe(x), which are not recognized by galectin-3. These results suggest that galectin-3 is present in Birbeck granules, where it retains reactivity for its glycoligands.

Detection of new diagnostic markers in pathology by focus on growth-regulatory endogenous lectins. The case study of galectin-7 in squamous epithelia.

Lectins represent one of pivotal regulators of the cell proliferation The potential of galectin-7 as a new prognostic marker was studied in normal and transformed squamous epithelia of both ectodermal (epidermis, cornea vs. trichoepithelioma, basal and squamous cell carcinoma) and endodermal (vocal fold epithelium vs. carcinoma) origin. Studies on the cultured cells were also performed. Expression of galectin-7 seems to be connected to the process of stratification, no matter of origin of epithelium. Its expression is significantly reduced in malignant cells, thus galectin-7 might be a differentiation marker of epithelial malignancies.

In vitro differences of neonatal and later postnatal keratinocytes and dermal fibroblasts.

Skin healing process is postnatally always associated with scarring of various extent. Based on the clinical experience of plastic surgeons, the healing after lip cleft reconstruction is surprisingly almost scar-less when it is carried out within a few first days after birth. This phenomenon is not seen in delayed cases. In order to decipher causative mechanism, we have isolated and studied principal cell populations, keratinocytes and fibroblast, from residual tissue samples after reconstructive operation (N=39) performed at various age (0-9 years). These cells play the pivotal role in the healing and that is why we focused on description of their phenotype and also functionality with respect to age. We have identified a population of remarkably small cells in explants from newborns (day 0-10). These small cells were strongly positive for markers of low differentiated keratinocytes, keratin-8 and -19, and moreover also for vimentin. In the explants cultures from older babies this population was missing. Fibroblasts from newborns and older patients differed namely in terms of nestin expression and also in the production of extracellular matrix components. We conclude that in vitro described properties of keratinocytes and fibroblasts in newborns could participate on the almost scar-less wound healing in earliest neonatal period.

Expression of galectin-3-reactive ligands in squamous cancer and normal epithelial cells as a marker of differentiation.

The definition of biological markers for oropharynx and larynx cancer is essential to predict their clinical behavior. Since cellular glycans play an important role in biological information transfer, we have employed an endogenous lectin, galectin-3, to examine in primary squamous carcinomas, lymph node metastases, and physiological squamous epithelia whether glycans recognized by this lectin are altered in relation to the state of differentiation. The expression of galectin-3 was concomitantly evaluated by immunohistochemistry using the A1D6 monoclonal antibody. In addition, other antibodies were used for the detection of cytokeratins and desmosomal proteins (desmoplakin-1 and desmoglein). The results show the expression of galectin-3-reactive ligands in moderately/highly differentiated carcinomas only in areas exhibiting a high level of keratinization. Except for one patient out of 14, metastatic cells in lymph nodes expressed no accessible binding sites for galectin-3. No galectin-3-reactivity was detected in the basal cell layer of all studied normal epithelia (which contains the proliferating cells). The suprabasal layers were positive in epidermis and epithelium of tongue and cornea and negative in epithelium of palatine tonsil. The tumor cells expressed galectin-3 with an intensity positively correlated with tumor differentiation. The position of galectin-3-reactive sites colocalized with the two tested desmosomal proteins. However, presence of these proteins was also detected in areas of tumor and suprabasal layers of tonsil epithelium where no binding reactivity for galectin-3 was found. The present study showed that expression of galectin-3-reactive glycoligands is differentiation-dependent in normal as well as malignant squamous cells. Colocalization of galectin-3-reactive sites with desmosomal proteins (desmoplakin-1 and desmoglein) suggests an association of the galectin-3 ligand(s) with the cell surface, pointing to a potential participation of galectin-3 in mediation of intercellular contacts in these tumor types.

Postmitotic basal cells in squamous cell epithelia are identified with Dolichos biflorus agglutinin--functional consequences.

Dolichos biflorus agglutinin (DBA) is a plant lectin specifically recognizing alpha-N-acetylgalactosamine. Controversial reports regarding the binding of DBA to the epidermis have been published. Using a double labeling procedure at the single-cell level, we studied the expression of DBA-reactive binding sites in conjunction with markers of cell proliferation and differentiation in normal human epidermis, cornea, and malignant tumors as well as in cultured keratinocytes. The results characterize the cells recognized by DBA as postmitotic early differentiating cells, identifiable by their lack of expression of the proliferation marker (Ki-67). The Golgi complex of a limited number of cultured keratinocytes was recognized by DBA and some of these cells show the accumulation of beta1 integrin chain in the Golgi complex. This process seems to be important for the migration of postmitotic cells from the basal to the suprabasal layers.

Silicone rubber-hydrogel composites as polymeric biomaterials. IX. Composites containing powdery polyacrylamide hydrogel.

A composite material has been prepared consisting of a silicone rubber matrix and particulate lightly cross-linked polyacrylamide hydrogel. The material, resembling common silicone rubber, is hydrophilic and swells in water like hydrogels. The polyacrylamide has a high specific surface area, a relatively low content of water-soluble low-molecular-weight compounds and, owing to its non-ionogenic character, a pH-independent swelling degree. For the composite material consisting of the silicone rubber and very fine powdery cross-linked polyacrylamide, we have measured the rate of swelling in water, the mechanical properties (tensile strength, break elongation, hardness, resilience), biological properties (implantation test, cytotoxicity, cell cultivation) and UV absorption of its water extracts. The polyacrylamide and polysiloxane purity, as the composite material starting components, has been determined to be satisfactory. As a result, a high swelling rate of the prepared composite material has been observed, resulting in reaching more than 70% wt of water of the equilibrium swelling. The results show that the composite material is suitable for biological and medical use.

Cultivation and grafting of human keratinocytes on a poly(hydroxyethyl methacrylate) support to the wound bed: a clinical study.

Cultured epithelial sheets on a textile support are used for the treatment of seriously burned patients. In this study we demonstrate a new procedure for the grafting of keratinocytes directly on a polymer cultivation support. This procedure is much easier in comparison with classical techniques, and encouraging results of clinical trials demonstrate the improved healing of the wound bed after the use of this procedure. There is no difference in the cytokeratine pattern (LP-34, cytokeratin-10) of the reconstructed epidermis and normal human skin.

Biocompatibility of HEMA copolymers designed for treatment of CNS diseases with polymer-encapsulated cells.

Surrounding the cells with a semipermeable polymeric membrane allows transplanting unmatched xenogeneic cells without a risk of their rejection. We prepared and tested several 2-hydroxyethyl methacrylate (HEMA) copolymers with alkyl methacrylates or acrylates to find out which was the most valuable for cell encapsulation. On the basis of optimum physical properties and good results of cytotoxicity tests, HEMA-EMA copolymer was chosen as a suitable candidate for encapsulation and immunoprotection of xenogeneic cells before their grafting into the central nervous system (CNS). To characterize the biocompatibility of p(HEMA-co-EMA) copolymer in the CNS, we implanted microcapsules made of this hydrogel into the brains of adult rats that were allowed to survive for 0.5, 1, 3, 6, and 9 months. Analysis of histological sections containing the implantation site was aimed at assessment of the cellular density at the implant-brain interface and identification of cell types participating in a tissue reaction. Our results indicated that the tissue reaction that was observed was caused largely by the implantation procedure because HLA-DR- and GSI-B4-positive macrophages/microglia infiltrated mainly the implantation channel. The number of these cells declined with time, which was true also for GFAP-positive reactive astrocytes, as well as for foreign body giant cells. The amount of connective tissue components surrounding the implanted microcapsules increased only slightly. These findings indicated that p(HEMA-co-EMA) hydrogel was well tolerated after implantation in the brain.

Cell adhesion on polytetrafluoroethylene modified by UV-irradiation in an ammonia atmosphere.

We report on the modification of polytetrafluoroethylene (PTFE) by exposure to the ultraviolet (UV) light of a Xe(2)*-excimer lamp at a wavelength of 172 nm in an ammonia atmosphere. Typical treatment times were up to 30 min. Subsequently, the samples were grafted with the amino acid alanine from an aqueous solution. The samples were characterized by means of optical transmission spectroscopy, laser-induced fluorescence and contact-angle measurements. We studied the adhesion of rat aortic smooth muscle cells (SMC) and mouse fibroblasts (3T3 cells) to the modified polymer samples using an in vitro technique, where the population density and spread of adhering cells is determined 24 h after seeding by image analysis. For both cell types the exposure of PTFE to UV-light in an ammonia atmosphere resulted in a significant increase in the number of adhering cells and in the size of their spreading area. The grafting with alanine enhanced this effect. Additional experiments with human endothelial cells (HEC) also demonstrated improved adhesion to modified PTFE. Thus, PTFE modified by our method appears to be a promising material for fabrication of artificial vascular prostheses and implants or for cultivation of skin substitutes.

Metabolic activity of cultured skin grafts cryopreserved in different forms.

Cultured epidermal cells in the form of coherent sheets have been used for the treatment of skin defects. Metabolic activity of fresh and in liquid nitrogen cryopreserved keratinocyte suspensions and three forms of coherent cultured skin sheets were compared with the aim to find the most appropriate form of skin cultures for cryopreservation. Keratinocytes cultured from cryopreserved suspensions formed a confluent layer in 8-10 days after thawing, showing 95% activity of the fresh confluent cultures. Cryopreserved cultured epidermal sheets attached to the bottom of the dish as well as recombined human/pig skin (RHPS) reached more than 70% of the metabolic activity of fresh grafts following 24 h regeneration in the incubator after thawing. Cultured epidermal sheets detached from the dish and mounted on tulle grass reached only 28% of the fresh graft metabolic activity under the same conditions.