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Locomotory behaviour of epitheliocytes and fibroblasts on metallic grids.

Behaviour of epitheliocytes and fibroblasts on special discontinuous substrata (metallic grids with square openings of 45x45 microm2) was examined in order to compare the ability of these cells to spread in two mutually perpendicular directions and to stretch over the void spaces. Two cell types with typical fibroblastic morphology, the AGO 1523 line of human foreskin fibroblasts and secondary cultures of mouse embryo fibroblasts, and three cell types with typical epithelial morphology, primary mouse hepatocytes, the IAR-2 line of rat liver cells and the MDCK line of canine kidney epithelial cells (clone 20) were used. We also examined the epitheliocytes (MDCK cells, clone 20) transformed to fibroblast-like morphology by treatment with hepatocyte growth factor/scatter factor (HGF/SF). Time-lapse video microscopy, scanning electron microscopy and immunofluorescence microscopy were used to examine cell reorganizations at various stages of spreading. It was found that early stages of spreading of fibroblasts and epitheliocytes were similar: the cell spread along two bars, perpendicular to each other (bar and crossbar), with the formation of a small triangular lamellar cytoplasm stretched over the opening. Later central parts of the bodies of the fibroblasts retracted from the bars so that the cells remained attached only by their polar lamellae. Successive expansions and partial retractions of these lamellae led to elongation of the cell body crossing several openings of the grid. Epitheliocytes, in contrast to fibroblasts, at the late stages of spreading did not retract their bodies and did not contract polar lamellae. As a result, their central lamellae stretched progressively over the openings. As a result of the treatment of MDCK epitheliocytes with HGF/SF the behaviour of the cells on the grids became similar to that of fibroblasts. It is suggested that these distinct spreading patterns of epitheliocytes and fibroblasts are due to the type-specific differences in the actin-myosin cortex. Experiments with microtubule-specific drugs, colcemid and taxol, indicate that the organization of this cortex is under microtubular control.

Actin Cytoskeleton↗

Non-reciprocal contact inhibition of locomotion of chick embryonic choroid fibroblasts by pigmented retina epithelial cells.

Using light and electron microscopy, we have confirmed an earlier observation that chick embryonic pigmented retina epithelial cells (PRE cells) seeded in vitro on cultured sheets of choroid fibroblasts, are able to spread. Spreading is as rapid (and shows the same dependence on lateral contact between PRE cells) as on a serum-coated culture substrate. After 1 h most cells are spreading on the upper surface of the choroid sheet, but after 4 h, some PRE cells can be found sandwiched between overlapping choroid cells, and thus have invaded the sheet. Choroid fibroblasts underlie PRE in vivo, but the ability of PRE cells to spread on cultured fibroblasts is not specific for choroid, since PRE cells spread also on BKH21 hamster kidney fibroblasts, and on fibroblasts from chick embryonic heart. As reported by others for various fibroblastic cells, choroid cells seeded on to choroid sheets or on to cultured PRE are unable to spread. A possible explanation is that spreading of adherent cells is contact-inhibited by the cells in the sheet, just as their leading edges are paralysed on contact, and thus locomotion is inhibited, when fibroblasts collide on a plane substratum. If spreading of seeded cells and cell locomotion are inhibited by the same mechanism, PRE cells should contact-inhibit choroid fibroblasts with which they collide, but not themselves be so inhibited. Using time-lapse cinemicrography, we have found this to be the case. We first established that in homotypic collisions, choroid fibroblasts do show contact inhibition of locomotion, despite the criss-cross (not well monolayered) appearance of confluent cultures. In heterotypic collisions between choroid and PRE we found the predicted nonreciprocal behaviour: the choroid leading edge is paralysed on collision, and the cell subsequently retracts, whereas the active PRE margin appears to be completely unaffected. Speed measurements from a series of such collisions show that the speed of choroid cells is markedly reduced on collision with PRE, whereas the slight slowing of PRE is not statistically significant. We have observed similar behaviour in heterotypic collisions between various epithelial and fibroblastic cells, and so it seems possible that non-reciprocity may prove general for this interaction. If so, it has important implications for the role of contact inhibition of locomotion in phenomena such as morphogenesis, wound healing and the invasiveness of carcinoma cells. On the one hand, non-reciprocal contact-inhibition of locomotion may permit the spreading of epithelia over mesenchymal cells, thus generating or restoring an epithelial bounding membrane. On the other hand, in the absence of other interactions, it would fail to inhibit the invasion of mesenchymal territory by aberrant epithelial cells, or presumably by epithelial free edges.

Animals↗

Fibroblasts from cancer patients display a mixture of both foetal and adult-like phenotypic characteristics.

We have previously reported that foetal and adult fibroblasts display distinctive migratory phenotypes when cultured on three-dimensional collagen gels. Both skin and tumour-derived fibroblasts from a significant proportion of patients with breast cancer were subsequently observed to display foetal-like migratory behaviour. In the accompanying paper concerned with the biochemical basis of these observations, we presented evidence that foetal fibroblasts and the foetal-like fibroblasts of cancer patients produce a soluble migration-stimulating factor (MSF) not made by normal adult cells. Data are presented here indicating that: (1) the spontaneous foetal-to-adult transition in migratory phenotype that foetal fibroblasts undergo after approximately 50-55 population doublings in vitro is correlated with a cessation of MSF production; (2) breast cancer patient fibroblasts do not undergo such a phenotypic transition and continue to produce MSF for their entire in vitro lifespan. These foetal-like cancer patient fibroblasts do, however, resemble normal adult cells by a number of other criteria, including population doubling potential, enhanced migration in the presence of serum compared to platelet-poor plasma, saturation cell density and morphology in confluent culture. These data indicate that the fibroblasts of breast cancer patients express a mixture of both foetal and adult phenotypic characteristics. Such a finding is consistent with published information indicating that foetal-to-adult transitions in various fibroblast phenotypic characteristics occur in a temporally disparate fashion during normal development, and further imply that cancer patient fibroblasts have undergone only certain of these transitions.

Cell Movement↗

Transforming growth factor-beta 1 promotes contraction of collagen gel by cardiac fibroblasts through their differentiation into myofibroblasts.

Myofibroblasts and transforming growth factor-beta 1 (TGF-beta 1) are key elements of cardiac tissue fibrosis development. The aim of this study was to determine whether the ability of TGF-beta 1 to affect the contractile activity of cardiac fibroblasts depends on their differentiation into myofibroblasts. Cardiac fibroblasts (from male adult Wistar rats) from passage 2 were therefore cultured to confluency and incubated on a hydrated collagen gel, both with and without TGF-beta 1 (0, 20, 40, 100, 200, 400 or 600 pmol/l), for 1, 2 and 3 days in a Dulbecco's Modified Eagle's Medium (DMEM) without fetal bovine serum (FBS). Growing cultures of cardiac fibroblasts were obtained by incubating second-passage fibroblasts in DMEM with 10% FBS with or without TGF-beta 1 (0 to 600 pmol/l) for 6 days. These fibroblasts were then further incubated on the collagen gel for 1, 2 and 3 days in DMEM without FBS. TGF-beta 1 dose-dependently increased the contraction of collagen gel mediated by cardiac fibroblasts, either added directly to the gel or after growing of the cardiac fibroblasts in the presence of TGF-beta 1 for 6 days, reaching a maximal effect at 100 pmol/l TGF-beta 1. In both culturing conditions, TGF-beta 1 also stimulated the [3H]-thymidine incorporation and the total protein content in the cardiac fibroblasts in the collagen gel lattice. TGF-beta 1 dose-dependently induced an increase in alpha-smooth muscle actin, a marker of myofibroblasts, in both culturing conditions. The TGF-beta 1-induced reduction of area of the collagen gel was negatively correlated to the TGF-beta 1-evoked appearance of alpha-smooth muscle actin in the collagen gel matrix. TGF-beta 1 increased the contractile activity of adult rat cardiac fibroblasts and their ability to differentiate into myofibroblasts. Because contractile activity was correlated with differentiation, the influence of TGF-beta 1 on cardiac fibroblast-induced collagen gel contraction may depend on the promotion of myofibroblast differentiation.

Actins↗

In vivo characterization of bone marrow-derived fibroblasts recruited into fibrotic lesions.

Fibroblasts, which are widely distributed and play a key part in tissue fibrosis, are phenotypically and functionally heterogeneous. Recent studies reported that bone marrow can be a source of tissue fibroblast. In the study reported here, we investigated in vivo characterization of bone marrow-derived fibroblasts recruited into various fibrotic lesions. Mice were engrafted with bone marrow isolated from transgenic mice expressing green fluorescent protein (GFP), and fibrotic lesions were induced by cancer implantation (skin), excisional wounding (skin), and bleomycin administration (lung). A small population of GFP+ fibroblast was found even in nonfibrotic skin (8.7% +/- 4.6%) and lung (8.9% +/- 2.5%). The proportion of GFP+ fibroblasts was significantly increased after cancer implantation(59.7% +/- 16.3%) and excisional wounding (32.2% +/- 4.8%), whereas it was not elevated after bleomycin administration (7.1% +/- 2.4%). Almost all GFP+ fibroblasts in fibrotic lesions expressed type I collagen, suggesting that bone marrow-derived fibroblasts would contribute to tissue fibrosis. GFP+ fibroblasts expressed CD45, Thy-1, and alpha-smooth muscle actin at various proportions. Our results suggested that bone marrow-derived fibroblasts expressed several fibroblastic markers in vivo and could be efficiently recruited into fibrotic lesions in response to injurious stimuli; however, the degree of recruitment frequency might depend on the tissue microenvironment.

Animals↗

The origin of fibroblasts and their role in the early stages of horizontal furcation defect healing in the beagle dog.

The origin of fibroblasts, their proliferative activity and roles in the early stages of periodontal repair were investigated in order to better understand the periodontal healing process in furcation defects of the beagle dog after guided tissue regenerative therapy. Newly divided cells were identified by immunolocalization of bromodeoxyuridine (BrdU) injected 1 hour prior to sacrificing the animals. At 1 and 2 weeks after creation of the defects, the lesions were occupied primarily by granulation tissue. Under this condition, periodontal ligaments (PDL) fibroblasts in a coronal portion of the remaining PDL close to wounds proliferated actively, migrated along the root surface and formed fibrous connective tissue on the surface. Similarly, the fibroblasts adjacent to the bone surface also showed proliferative activity and engaged in active formation of fibrous connective tissue on the bone surface. The majority of labeled cells in both areas were located in the extravascular area. At 3 and 4 weeks, the defects were filled with an increased amount of new connective tissue and bone. The labeled fibroblasts were preferentially found in the most coronal portion of connective tissue formed on the root surface that was in direct contact with inflamed tissue, and the collagen fibers projected into granulation tissue. In areas of active bone formation, numerous labeled fibroblasts were located in connective tissue adjacent to the newly-formed bone. However, fibroblasts in the endosteum of new bone were rarely labeled These results indicate that fibroblasts involved in periodontal repair originate primarily from both the remaining PDL and alveolar bone, and actively engage in fibrous connective tissue formation in the early stages of periodontal repair The ability of PDL fibroblasts to proliferate, migrate, and form connective tissue on the root surfaces in the early repair stages appears to play a crucial role in the formation of the PDL and cementum, and consequently, in periodontal regeneration in the absence of root resorption and ankylosis. As the formation of new connective tissue and bone continues, the precursor cells for fibroblasts and osteoblasts are supplied locally through the continued divisions of the fibroblastic cells in association with the newly-formed connective tissue. Paravascular and endosteal cells appear to be minor contributors to new cell population during furcation defect repair in the beagle dog.

Alveolar Process↗

An investigation of preferential fibroblast wound repopulation using a novel in vitro wound model.

To overcome the difficulties of studying wounding and wound repopulation in monolayer systems, a 3-dimensional model of wound repopulation has been developed which allows the in vitro investigation of fibroblast migration in response to experimental wounding. This model was utilized to determine whether fibroblasts derived from sites which demonstrate preferential healing (child and oral mucosal fibroblasts) possessed an increased ability to repopulate experimental wounds when compared to adult dermal fibroblasts. Fibroblasts were established from specimens derived from healthy donors undergoing minor elective surgery. Standard wounds were created in fibroblast populated collagen lattices (FPCLs) which were then overlaid upon an extracellular wound matrix. Fibroblast repopulation of the wounds was studied over 12 days using light- and scanning electron microscopy and quantified using computerized image analysis. Wound repopulation by fibroblasts derived from child donors (n = 3) was significantly (P < 0.001) more rapid than their adult tissue-matched counterparts (n = 3). Wound repopulation by oral mucosal fibroblasts (n = 3) was significantly greater than that exhibited by age-matched dermal fibroblasts (n = 3; P < 0.05). These differences were not reflected in differences in DNA synthesis (P > 0.5) or cell number (P > 0.5) within similar attached FPCL systems. These findings further support the concept of a gradual transition from the fetal to adult phenotype in wound healing. The potential applications of the model are discussed.

Adult↗

Increased proliferation, collagen, and fibronectin production by hereditary gingival fibromatosis fibroblasts.

HEREDITARY GINGIVAL FIBROMATOSIS (HGF) is a fibrotic enlargement of the gingiva. HGF gingiva contains large amounts of interstitial collagen and other extracellular matrix (ECM) molecules. Increased proliferation and elevated production of the ECM molecules type I collagen and fibronectin (FN) could contribute to the clinical increased bulk of HGF gingiva. Fibroblast strains from HGF gingiva and normal human gingival fibroblast strains (GN) were used in this in vitro study. Fibroblast proliferation was determined by ELISA which measured the incorporation of 5-bromo-2'-deoxyuridine into DNA. The results showed that HGF fibroblast strains proliferated more rapidly than GN fibroblasts (68% to 488% increase, depending on the strains) (P < or = 0.01), the only exception being one HGF strain versus one normal strain. All HGF strains produced greater amounts of FN (measured by ELISA) than all of the normal fibroblast strains (23% to 49% increase, depending on the strain) (P < or = 0.04). Similarly, all HGF strains made significantly greater (P < or = 0.3) amounts of type I collagen (also measured by ELISA) than all of the normal strains (55% to 235% increase, depending on the strain). The results show that, in vitro, HGF fibroblasts display several phenotypic characteristics of activated fibroblasts: increased proliferative rates as well as increased production of FN and type I collagen, consistent with in vitro studies of fibroblasts derived from other types of fibrotic tissue. These results suggest that the increased proliferation of HGF fibroblasts and their increased production of extracellular matrix molecules such as collagen and FN may contribute to the clinical gingival enlargement characteristics of HGF.

Analysis of Variance↗

Cyclosporin A induces proliferation in human gingival fibroblasts via induction of transforming growth factor-beta1.

BACKGROUND: Cyclosporin A (CsA) is a widely used immunosuppressant that causes significant side effects including gingival overgrowth. The pathogenesis of this condition is not fully understood; however, recent studies show that CsA regulates the transcription of several cytokines including transforming growth factor-beta 1 (TGF-beta1). In this study, we evaluated the effects of CsA and TGF-beta1 on human normal gingival (NG) fibroblast proliferation, and explored a possible autocrine stimulation of TGF-beta1 as a cellular regulator of proliferation induced by CsA in NG fibroblasts. METHODS: NG fibroblast cell lines were incubated with increasing concentrations of CsA or TGF-beta1 and the proliferation index determined by automatic cell counting, BrdU incorporation, PCNA expression, and mitotic potential. To determine the effect of TGF-beta1 on the proliferation rate of NG fibroblasts under CsA treatment, NG fibroblast cultures were simultaneously treated with CsA and antisense oligonucleotides against the translation-start site of the TGF-beta1 mRNA. RESULTS: Treatment of NG fibroblasts with CsA or TGF-beta1 significantly stimulated the cell proliferation in a dose-dependent manner. Furthermore, neutralization of TGF-beta1 production in CsA-treated NG fibroblasts inhibited CsA's effect on NG fibroblast proliferation, demonstrating an autocrine stimulatory effect of TGF-beta1 in CsA-treated NG fibroblast proliferation. CONCLUSION: The results presented here suggest that CsA stimulatory induction of NG fibroblast proliferation is mediated via TGF-beta1 in an autocrine fashion.

Analysis of Variance↗

Isolation of primary rat liver fibroblasts.

INTRODUCTION: One of the major advances in liver research in the past decade was the ability to isolate distinct liver cell populations. Although there are established methods of isolating hepatocytes, cholangiocytes, and stellate cells, before this study no technique for liver fibroblast isolation had been devised. Consequently, we developed a technique to isolate primary rat liver fibroblasts. METHODS: Fibroblasts were isolated from a freshly perfused rat liver with a modification of the procedure for isolation of rat cholangiocytes. Cell markers were assessed with the use of confocal immunofluorescence. Cell morphology was assessed with transmission electron microscopy. Expression of procollagen-1 was assessed by reverse transcription polymerase chain reaction. RESULTS: The appearance of cells with fibroblast morphology was first noted at 48 hours, and almost all cells in culture had fibroblast morphology at 96 hours. Putative fibroblasts stained for vimentin, but not for smooth muscle actin, von Willebrand factor, or cytokeratins. Cell morphology was consistent with that of fibroblasts and showed no features of epithelial, endothelial, or smooth muscle cells. Liver fibroblasts expressed procollagen-1 mRNA. CONCLUSION: Primary isolated rat fibroblasts can be produced from a freshly perfused rat liver with a modification of standard cell culture methods. The role of fibroblasts in liver physiology can now be studied directly.

Animals↗

Discoidin domain receptor 1 contributes to the survival of lung fibroblast in idiopathic pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF), characterized by fibroblast proliferation and accumulation of extracellular matrix, including collagen, is a chronic progressive disorder that results in lung remodeling and fibrosis. However, the cellular mechanisms that may make fibroblasts resistant to apoptosis have not been completely elucidated. Discoidin domain receptor 1 (DDR1), a receptor tyrosine kinase whose ligand is collagen, is expressed in vivo and contributes in vitro to leukocyte differentiation and nuclear factor (NF)-kappaB activation, which may play an important role in fibroblast survival. In this study, we examined in vivo and in vitro DDR1 expression and its role in cell survival using fibroblasts obtained from IPF and non-IPF patients. Immunohistochemically, fibroblasts present in fibroblastic foci expressed endogenous DDR1. The DDR1 expression level was significantly higher in fibroblasts from IPF patients, and the predominant isoform was DDR1b. In IPF patients, DDR1 activation in fibroblasts inhibited Fas ligand-induced apoptosis and resulted in NF-kappaB nuclear translocation. Suppression of DDR1 expression in fibroblasts by siRNA abolished these effects, and an NF-kappaB inhibitor abrogated the anti-apoptotic effect of DDR1 activation. We propose that DDR1 contributes to fibroblast survival in the tissue microenvironment of IPF and that DDR1 up-regulation may occur in other fibroproliferative lung diseases as well.

Actins↗

Reciprocal epithelial: fibroblast interactions in the control of fetal and adult rat lung cells in culture.

Intercellular communication between epithelial cells and fibroblasts of the alveolar wall has been postulated from studies of lung development and repair. We examined the epithelial cell-fibroblast interactions with respect to growth control and epithelial cell function using cultured fetal and adult lung cells. The role of diffusing factor(s) as compared to direct cell-to-cell contact was studied by culturing epithelial cells either on a permeable culture well insert over fibroblasts or in co-culture with fibroblasts. The results show that the normal low proliferative rate of epithelial cells in culture is increased when exposed to fibroblast supernatants. In contrast, epithelial cells (particularly from adult lung) secrete a factor that suppresses fibroblast growth when cultured with a filter between the cell types. However, when cell-cell contact occurs in co-culture, the growth rate of fibroblasts is greatly increased. Synthesis of disaturated phosphatidylcholine by epithelial cells is increased under serum-free conditions and further rises when fetal epithelial cells are exposed to steroid-treated fibroblasts, when the cell types are separated, and when cells are in contact. This indicates that a fibroblast-derived factor stimulates epithelial differentiation, and morphologic evidence relating the appearance of lamellar bodies to the areas of direct epithelial cell-fibroblast contact was found. The results indicate the complex interdependence of these two types of cell where a secretory product of one cell or direct cell-cell contact may alter when regulatory control of the other cell type. These interactions are likely to be important in orderly development and in the reparative response of the lung to injury.

Animals↗

Fibroblast inhibition does not promote normal lung repair after hyperoxia.

Severe alveolar epithelial injury disrupts the normal epithelial cell-fibroblast relationship, leading to abnormal repair and the uncontrolled growth of fibroblasts. It is postulated that selective inhibition of fibroblasts growth after injury may allow epithelial regeneration to occur, reestablish fibroblast control, and reduce fibrosis. This hypothesis was studied using organ cultures after lung injury was induced in vivo by exposing mice to 90% oxygen for 6 days to produce necrosis of Type 1 epithelium. When explants of this lung tissue were cultured, proliferation of cuboidal epithelial cells was reduced, whereas fibroblast growth and hydroxyproline (HYP) levels were significantly higher than in controls. In attempts to inhibit fibrosis, explants were also cultured in the presence of a proline analog, L-azetidine carboxylic acid (LACA). At concentrations that reduced fibroblast proliferation, epithelial repair was also inhibited. The explants appeared fibrotic, and reduced HYP/DNA was due to lower DNA synthesis. Using pure cell cultures, LACA reduced fibroblast but not epithelial growth, and also abolished the usual increase in epithelial cell proliferation that control cells show when exposed to fibroblast supernatants. These results provide further evidence of interdependence between epithelial cells and fibroblasts such that agents that inhibit fibroblast growth after lung injury either directly or indirectly retard regeneration of the overlying epithelium, and so fail to produce normal repair.

Animals↗

Comparative study on motility of the cultured fetal and neonatal dermal fibroblasts in extracellular matrix.

One of the differences between fetal and adult skin healing is the ability of fetal wounds heal without contraction and scar formation. Extracellular matrix (ECM) provides a substratum for cells adhesion, migration, and proliferation and can directly influence the form and function of cells. As motility is essential for many important biological events, including wound healing, inflammatory response, embryonic development, and tumor metastasis, this study was designed to compare the motilities cultured dermal fetal and neonatal fibroblasts in the extracellular matrix. The motility of cultured fetal and neonatal fibroblasts was compared using a video-microscopy system that was developed in combination with a self-designed CO2 mini-incubator. To determine migration speed, cells were viewed with a 4X phase-contrast lens and video recorded. Images were captured using a color CCD camera and saved in 8-bit full-color mode. We found that cultured fetal fibroblasts move faster than neonatal fibroblast on type I collagen (fetal fibroblast, 15.1 micrometer/hr; neonatal fibroblast, 13.7 micrometer/hr), and in fibronectin (fetal fibroblast, 13.2 micrometer/hr; neonatal fibroblast, 13.0 micrometer/hr) and hyaluronic acid (fetal fibroblast, 11 micrometer/hr; neonatal fibroblast, 9.8 micrometer/hr).

Cell Movement↗

Systemic sclerosis (scleroderma): specific autoantigen genes are selectively overexpressed in scleroderma fibroblasts.

The pathogenesis of systemic sclerosis (SSc) involves complex interactions between activated fibroblasts eventually leading to fibrosis, and impaired immune tolerance characterized by a variety of circulating SSc-specific autoantibodies. The expression of autoantigens in fibroblasts, a key target tissue in SSc, may play an important role in this process. To obtain a global view of this process, we examined gene expression profiles of SSc dermal fibroblasts using cDNA microarrays. The results show that dermal fibroblasts from SSc patients obtained from either affected or unaffected skin displayed a characteristic pattern of increased SSc autoantigen gene expression compared with that from normal controls. In particular, fibrillarin (p = 0.028), centromeric protein B (p = 0.01), centromeric autoantigen P27 (p = 0.042), and RNA polymerase II (220 kDa; p = 0.02) were significantly overexpressed in SSc fibroblasts. Quantitative RT-PCR confirmed overexpression of these autoantigens and also revealed increased levels of DNA topoisomerase I transcripts in SSc fibroblasts compared with normal control fibroblasts (p = 0.0318). The polymyositis/scleroderma autoantigen gene was overexpressed in some SSc patients (p = 0.09). To examine the specificity of these overexpressed autoantigen genes for SSc and its tissue specificity for fibroblasts, cDNA microarrays of dermal fibroblasts from patients with eosinophilic fasciitis and scleromyxedema were studied as well as PBMC and muscle biopsies from SSc patients. None of these tissues showed significant alterations in gene expression of SSc-specific autoantigens. Therefore, SSc-associated autoantigen genes are selectively overexpressed in SSc dermal fibroblasts, a major tissue involved in disease pathogenesis.

Autoantigens↗

[The inhibitory effect in vitro of salvia miltiorrhiza and tetramethyl pyrazine on the growth of fibroblasts].

In order to investigate the inhibitory effect of salvia miltiorrhiza (SM) and tetramethyl pyrazine (TP) on scartricial fibroblast, the hypertrophic scar tissue of chest was chosen for culture of fibroblasts, and the influence of SM and TP on fibroblasts was observed, The effect of the drugs on the growth of fibroblasts, on DNA synthesis of fibroblasts and on mitosis index of fibroblasts were all determined quantitatively. The results showed: 1. SM and TP could inhibit significantly the growth of the fibroblasts, the inhibitory effect was irreversible when the concentration of the drugs reached 5 mg/ml and 500 micrograms/ml respectively; 2. SM and TP could inhibit the absorption of 3H-TdR and this effect was correlated positively to the dosage of the drugs and; 3. SM and TP could reduce the mitosis index of fibroblasts. It was concluded that SM and TP had definite depressive effect on growth of fibroblasts which was correlated positively with the concentration of drugs and duration of application. The inhibitory effect of the drugs on fibroblasts was mainly through inhibition of synthesis of DNA.

Burns↗

Nocodazole, vinblastine and taxol at low concentrations affect fibroblast locomotion and saltatory movements of organelles.

Microtubules (MTs) are essential for the maintenance of asymmetric cell shape and motility of fibroblasts. MTs are considered to function as rails for organelle transport to the leading edge. We investigated the relationship between the motility of Vero fibroblasts and saltatory movements of particles in their lamella Fibroblasts extended their leading edges into the experimental wound at a rate of 20+/-11 microm/h. Intracellular particles in the front parts of the polarized fibroblasts moved saltatorily mainly along the long axis of the cells. MT depolymerization induced by the nocodazole at a high concentration (1.7 microM) resulted in the inhibition of both fibroblast motility and saltatory movements of the particles. Taxol (1 microM) inhibited the fibroblast locomotion but not the saltatory movements. The saltatory movement pattern was disorganized by taxol by decreasing the portion of longitudinal saltations and consequently by increasing the part of saltations perpendicular to the cell long axis. This effect may be explained by disorganization of the MT network resulting from the inhibition of dynamic instability. To further investigate the relationships between the MT dynamics instability, saltatory movements, and fibroblast locomotion, we treated fibroblasts with microtubule drugs at low concentration (nocodazole, 170 nM; vinblastine, 50 nM; and taxol, 50 nM). All these drugs induced rapid disorganization of the saltatory movements and decreased the rate of cell locomotion. Simultaneously, the amount of acetylated (stable) MTs increased. The treatment also induced reversible changes in the actin meshwork. We suggest that decrease in the fibroblast locomotion rate in the case of MT stabilization occurred because of the appearance of numerous free MTs. Saltations along free MTs are poorly organized and, as a result, the number of organelles reaching the fibroblast leading edge decreases.

Animals↗

An in-vitro model of scirrhous carcinoma of the stomach using stomach fibroblasts derived from gastric cancer patients.

BACKGROUND/AIMS: The mechanisms of the particular stromal changes that occur upon cancer invasion by scirrhous carcinoma of the stomach, in particular, the relationships among cancer cells, stomach fibroblasts and collagen, a major constituent of the stroma of the invasive tumor, have yet to be clarified. METHODOLOGY: Three different human fibroblast cell lines (TIG-101, MF-2, MKF-1) and a cancer cell line derived from scirrhous carcinoma of the stomach (KATO III) were cultured three-dimensionally in collagen gels to investigate collagen gel contraction by these cells as a model of scirrhous carcinoma of the stomach. RESULTS: The gels contracted and gradually decreased in size in all of the fibroblast (TIG-101, MF-2 and MKF-1) cultures, but not in the KATO III culture, and the extent of gel contraction was not uniform among the fibroblast cell lines. The extent of gel contraction when fibroblasts derived from stomach (MF-2, MKF-1) were co-cultured with KATO III cells in collagen gel was almost similar to that of fibroblasts alone. Moreover, microscopic examination following Masson's trichrome staining revealed condensation and remodeling of collagen fibrils only around the fibroblast cells. CONCLUSIONS: The extent of collagen gel contraction by fibroblasts may depend on their in vivo origin. This property appears to be characteristic of fibroblasts, but not of malignant epithelial cells, under this culture system. Furthermore, the results of the present study demonstrate that stomach fibroblasts may play an important role in the stromal changes associated with scirrhous gastric cancer.

Adenocarcinoma, Scirrhous↗