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Results for “Stromal-epithelial interactions”

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PubMed1992

Serum-free culture of stromal and functionally polarized epithelial cells of guinea-pig endometrium: a potential model for the study of epithelial-stromal paracrine interactions.

Stromal and glandular epithelial (GE) cells were isolated from guinea-pig endometrium and growth to near confluency (6-8 days) in primary culture on plastic surfaces in a serum-supplemented medium (SSM). The stromal cells were subcultured on plastic dishes and maintained for 72 h in SSM. Then SSM was replaced by a chemically defined medium (CDM) and the stromal cells grown to confluency (5-7 days). The GE cells were subcultured in CDM, on a basement membrane matrix (Matrigel) applied to permeable Millicell-PC filters, and grown to confluency (5 days). Homogeneity of the subcultured endometrial cell populations was ascertained immunocytochemically. The filter-cultured GE monolayers were polarized morphologically, and displayed epithelial-specific specialized structures. These monolayers had functional tight junctions as verified by a measurable transepithelial resistance. The subcultured cell populations were distinguished by an analysis of their cellular and secretory proteins after labelling with [35S]-methionine and analysis by polyacrylamide gel electrophoresis. The filter-cultured GE monolayers allowed identification of the proteins released vectorially in the apical or the basal secretory compartment, thus demonstrating the functional polarization of GE cells in this bicameral culture system. Within the defined conditions of this culture system, the paracrine factors released by the two endometrial cell populations as well as the interplay of stromal-epithelial interactions and ovarian hormones could be investigated.

Animals↗

PubMed1981

Isolation of cells from rat seminal vesicles and epididymis and their use in studying androgen action.

Cells isolated enzymically from seminal vesicles and epididymides of normal and castrated rats were shown by electron microscopy to be intact and representative of the tissue. The cells synthesize and secrete tissue-specific proteins. Short-term incorporation of [3H]uridine and [35S]methionine was measured to determine the effects of castration on RNA and protein synthesis. Epididymal cells and tissue incorporated uridine at similar rates which were unaltered by castration. Similarly castration failed to diminish uridine incorporation by seminal vesicle cells and tissue. Therefore, androgens may principally control RNA degradation. A similar situation pertained to methionine incorporation by epididymal cells and tissue so here too control may be via protein degradation. In contrast, castration greatly decreased methionine incorporation by seminal vesicle tissue but not by isolated cells. Isolated cells were more active than in tissue, particularly those from castrated rats, and may be released from stromal-epithelial interactions and controls.

Androgens↗

PubMed1992

Detection and partial purification of a potent mitogenic factor for human thyroid follicular cells.

Normal adult human thyroid follicular cells have an extremely limited proliferative capacity in vitro. No previously studied mitogen, including thyrotropin (TSH) or epidermal growth factor (EGF), has in our hands resulted in a significant improvement over the 3-4% nuclear [3H]thymidine pulse-labelling index (LI) obtainable with 10% fetal calf serum. Here we report the detection in the conditioned medium from a sub-clone of NIH3T3 fibroblasts of a mitogenic activity capable of increasing this response up to 10-fold, to an LI of over 20%, together with an even greater relative stimulation of mitotic activity. Preliminary characterisation has excluded EGF and TGF alpha, and demonstrated that the activity is bound reversibly by heparin-Sepharose, thus pointing to a member of the heparin-binding fibroblast- or hepatocyte-growth factor families. This material should have wide practical application in facilitating primary culture of follicular cells, and may reveal new mechanisms of stromal-epithelial interaction regulating normal and neoplastic thyroid growth in vivo.

Cell Division↗

PubMed1992

Prostate and bone fibroblasts induce human prostate cancer growth in vivo: implications for bidirectional tumor-stromal cell interaction in prostate carcinoma growth and metastasis.

Prostate cancer selectively metastasizes to the axial skeleton to produce osteoblastic lesions, which suggests that bidirectional paracrine interactions exist between prostate cancer and bone cells. To evaluate the role of tumor-stromal cell interaction and stromal-specific growth factors in prostate cancer growth and dissemination, we coinoculated nontumorigenic human prostate cancer cells (LNCaP) and various tissue-specific fibroblasts subcutaneously in athymic mice. LNCaP tumors were induced most consistently by human bone fibroblasts (62%), followed by two prostate fibroblast cell lines (31% and 17%), but not by lung, kidney, or embryonic 3T3 fibroblasts. Carcinomas formed preferentially in male hosts, demonstrating in vivo androgen sensitivity. Immunohistochemical and biochemical techniques confirmed the human prostate component of these tumors and were paralleled by elevations in serum prostate specific antigen. In vitro mitogenic assays revealed a two-to three-fold bidirectional stimulation between LNCaP and bone or prostate fibroblast conditioned media, but not lung, kidney, or 3T3 fibroblast conditioned media. A novel method developed to deliver concentrated bone or prostate fibroblast conditioned media in vivo using a slowly absorbed matrix (gelfoam) also induced tumor formation, emphasizing the importance of fibroblast growth factors in LNCaP tumor formation. Northern analysis identified the stromal compartment as the primary source of extracellular matrix (collagen, fibronectin), while only LNCaP cells expressed transforming growth factor alpha. Although LNCaP and stromal cells express basic fibroblast growth factor (bFGF), the bidirectional paracrine-mediated mitogenic activity between these cells is not inhibited by anti-bFGF antibodies, suggesting that other undefined growth factors may be involved in stimulating LNCaP growth. These observations illustrate the importance of stromal-epithelial interaction in prostate tumor growth and suggest that extracellular matrix and paracrine-mediated growth factors play a role in prostate cancer growth and metastasis.

Androgens↗

PubMed1994

Uterine endocrinology and paracrinology: insulin-like growth factor binding protein-1 and placental protein 14 revisited.

A large number of proteins and peptides have been identified in the endometrium where they are likely to exert local biological effects. These substances may be enzymes, their inhibitors, proteinases, proteinase inhibitors, hormones, or bioactive peptides with diverse functions. Endometrial function and embryo-endometrial interactions require synchronized actions between endocrine and local factors. As examples of local factors recent studies on the insulin-like growth factor (IGF) system and placental protein 14 (PP14) are reviewed. IGF binding protein-1 (IGFBP-1) and PP14 are products of the secretory phase endometrium: IGFBP-1 is produced by decidualized stromal cells and PP14 by glandular epithelial cells. IGFBP-1 may inhibit the action of IGFs at the endometrial-trophoblastic interphase, and it may also have a role in stromal-epithelial interaction. PP14 has immunosuppressive properties, and recent findings indicate that it may play a part in the fertilization process by inhibiting binding of spermatozoa to the zona.

Carrier Proteins↗

PubMed1995

Development and characterization of an in vitro gingival epithelial model.

A 3-dimensional gingival epithelial model has been developed and characterized. Oral epithelial cells and connective tissue fibroblasts were isolated from human gingival tissue and used to create an in vitro oral mucosa co-culture model. Fibroblasts were seeded on a scaffold of nylon mesh, allowed to proliferate and secrete collagen and extracellular matrix proteins to form a stroma capable of supporting the growth of epithelial cells. Epithelial cells were seeded on top of a confluent stromal layer, proliferated and differentiated to form a stratified squamous epithelium. Resident epithelial cells were stimulated, by manipulation of growth medium and culture conditions, to form a multi-layered oral mucosa-like tissue. Histologic analyses revealed cellular architecture exhibiting stromal-epithelial interaction which supports the growth and differentiation of an epithelial layer. Immunohistochemical analyses confirmed production of types I and III collagen. Immunofluorescence of the stromal layer identified type IV collagen and fibronectin. Fibronectin was also detected on surface epithelium. Differentiation of basal, spinous and granular cells was observed, and the presence of differentiation markers, acidic (K10, 14-16, 19) and basic (K1-8) cytokeratins were confirmed using broad spectrum cytokeratin antibodies, AE1 and AE3. Development of a discontinuous basal lamina zone, with hemidesmosomes, was observed by electron microscopy. The co-culture was metabolically active, as measured by the thiazoyl blue (MTT) assay for mitchondrial function and [3H] thymidine incorporation into DNA. The human gingival epithelial co-culture model was viable up to 35 days post-epithelial seed. This model may offer opportunities for limited study of periodontal tissue responsiveness.

Basement Membrane↗

PubMed1989

Differentiation of rat intestinal epithelial cells is induced by organotypic mesenchymal cells in vitro.

Stromal-epithelial interaction is a potent driving force in the developing intestinal mucosa which ensures tissue specific cellular differentiation. The mechanisms involved are relevant to tissue renewal in adult organs yet they have not been elucidated because of the lack of appropriate in vitro models. In this study, we have investigated the interaction between intestinal mesenchymal and epithelial cells at the cellular level in vitro. Fetal rat intestinal epithelial cell colonies explanted in vitro on the 15th day of gestation, which failed to mature in plain monocultures, were reassociated in coculture with three different types of mesenchyme:fetal skin, gastric and intestinal mesenchyme. Only fetal epithelial cells cocultured with intestinal (homologous) mesenchyme acquired definite signs of differentiation within three to six days. These primitive epithelial cells were shown by electronmicroscopy to become highly polarized, connected by tight junctions and covered with a regular brush border. Three brush border enzymes were strongly expressed in homologous cocultures and their activity was sensitive to dexamethasone. In contrast, fetal epithelial cells cocultured with skin or stomach derived mesenchyme under identical conditions failed to differentiate in vitro: they remained flat, unpolarised and expressed only low enzyme activity. The unique potential of the small intestinal mesenchyme to promote intestinal epithelial differentiation is discussed.

Animals↗

PubMed1994

Pathophysiology of benign prostatic hyperplasia.

The exact morphogenesis of benign prostatic hyperplasia (BPH) is unknown, but morphologic observations and different etiologic theories, such as the stem cell, dihydrotestosterone, and stromal-epithelial interaction hypotheses, help to explain some of the findings. For example, the initial changes in the development of BPH may result from an activation of mesenchymal clones with embryonal functions that stimulate development of the glandular component. This, in turn, induces the development and maturation of the stromal component. In areas that lack epithelial elements, such as those in the periurethral zone, the interaction stops and only embryonal small stromal nodules remain. On the other hand, the decrease in endocrine-paracrine cells may alter the normal local hormonal equilibrium of the periurethral area and may be an inducing factor in the development of BPH.

Humans↗

PubMed1992

Role of stroma in oestrogen-induced epithelial proliferation.

To examine the role of stromal-epithelial interactions in the response of epithelial cells to oestrogens, tissue recombinations were prepared with epithelium (E) and stroma (S) from the vagina (V) and urinary bladder (BL), that is between oestrogen target tissues (VS and VE) and non-target tissues (BLS and BLE). Following 3 weeks of growth in intact female hosts, ovariectomy was performed and 1 week later the hosts subjected to various hormonal treatments. Whereas homotypic vaginal tissue recombinations (VS+VE) exhibited epithelial cornification and mucification (cycling), this activity was not observed in homotypic bladder recombinants (BLS+BLE) or in heterotypic tissue recombinants between vaginal and bladder tissues (VS+BLE and BLS+VE). In BLS+VE recombinants the epithelium remained atrophic and failed to respond to exogenous oestrogen alone or in combination with progesterone. This lack of hormonal responsiveness of vaginal epithelium was completely reconstituted when the epithelium of BLS+VE recombinants was recovered and reassociated with fresh vaginal stroma (VS). Examination of epithelial proliferative activity ([3H]thymidine labelling index) demonstrated a marked oestrogen-induced increase in epithelial proliferation in VS+VE recombinants. BLS+BLE recombinants were unresponsive to oestrogen as were recombinants composed of BLS+VE. However, when bladder epithelium was grown in association with vaginal stroma (VS+BLE) the epithelium exhibited an 8-fold oestrogen-induced increase in labelling index over oil-treated specimens. The lack of an oestrogen-induced proliferative response of vaginal epithelium in BLS+VE recombinants was reversed when the vaginal epithelium of these recombinants was recovered and reassociated with fresh vaginal stroma. These results indicate that the effects of oestrogen and progesterone on both epithelial differentiation and proliferation are critically dependent upon the appropriate stromal environment.

Animals↗

PubMed1992

Retinal pigment epithelium-stromal interactions modulate hyaluronic acid deposition.

Hyaluronic acid (HA) is a major component of the extracellular matrix (ECM) and is particularly prominent in various structures of the eye. Choroidal mesenchymal fibroblasts (CHM) and fetal retinal pigment epithelial (fRPE) cells were cultured individually and in cocultivation, as a paradigm for ocular stromal-epithelial interactions. Such interactions are thought to be a key mechanism for the modulation of the ECM and of HA deposition in the region of Bruch's membrane and related structures. In cocultivation, increased levels of HA production were observed, more than the sum of the two cell types grown individually. Conditioned medium from fRPE cultures placed over CHM cells was able to enhance production in such cells several-fold, demonstrating that cell-cell contact was not needed for this enhanced production. On the other hand, when conditioned medium from CHM fibroblasts was added to the fetal RPE cells, no increase in HA production was observed. A soluble HA-stimulating factor apparently released by fRPE cells in a paracrine manner enhanced HA production in CHM cells. The fRPE cell-conditioned media was unable to exert this effect on the fRPE cells themselves. The fRPE cells may lack the appropriate receptor. Alternatively, they may not have the biosynthetic machinery for augmented HA production.

Cell Communication↗

PubMed1988

Kinetic and morphometric responses of heterogeneous populations of experimental breast cancer cells in vivo.

Although the hormone responsiveness of some breast cancers is well known, the differential sensitivity of tumor cell subpopulations to hormonal effects is not well established. These experiments were designed to address this issue using the hormone-responsive N-nitrosomethylurea-induced rat mammary tumor. Rats bearing these tumors were randomly assigned to no treatment, 7-day castration, and 7-day castration followed by 1-, 3-, 7-, and 10-day treatment with estradiol benzoate (5 micrograms) and perphenazine (1 mg) to stimulate prolactin release. Under these conditions, the proportion of different cell populations was estimated with morphometric analysis, while their replicative activity was assessed using [3H]thymidine autoradiography. In tumors of intact rats the fractions of glandular epithelial, myoepithelial, and nonepithelial cells were 88.2%, 3.8%, and 8.0%, respectively. All cell types manifested a similar kinetic response to our hormonal treatments characterized by a drastic decline in the labeling index after castration followed by a progressive increase with hormone repletion which peaked on Day 7 of treatment. The magnitude of the response was, however, greater in the epithelial components of the tumor (glandular and myoepithelial cells), where the peak labeling indices significantly exceeded those observed in the tumors of control intact rats. Castration reduced the proportion of glandular cells while increasing the fractions of myoepithelial and nonepithelial cells. Furthermore, castration reduced the volume of the glandular-epithelial cells by 35%, which accounted for approximately half of the overall tumor volume reduction induced by ovariectomy. These alterations in tumor morphology were partially reversed by hormone repletion. These results underscore the exquisite hormonal sensitivity of different cellular counterparts of this experimental breast cancer with regard to both kinetic and morphological characteristics. They also provide support for stromal-epithelial interaction in the hormonal modulation of breast cancer growth.

Animals↗

PubMed1978

Quantitative determination of prostatic epithelial and stromal hyperplasia by a new technique. Biomorphometrics.

Recent studies of neonatal and pathologic growth of the prostate have postulated the possible importance of stromal-epithelial interaction in the control of prostatic growth. To allow further analysis of the possible importance of this interaction, a new technique has been developed that permits quantification of the total number of stromal and epithelial cells in the prostate gland. This technique has been termed biomorphometrics and is a combination of standard morphometric and biochemical methodology. This method has been applied to analyze the hormonal response of the stromal and epithelial cells of the rat ventral prostate.

Animals↗

PubMed1981

A histoquantitative study on the effects of castration on the rat ventral prostate lobe.

The effects of castration on the rat ventral prostate was studied utilizing an improved histoquantitative technique. Both volumetric fractions of the tissue compartments and their fractional weights, or, 'total amounts', were calculated during an observation period of 30 days. In addition, the surface area, length and mean diameter of the glandular tubules were recorded. The changes in the mean free distance between the tubules were recorded. The changes in the mean free distance between the tubules ('thickness' of the interacinar tissue) and the mean distance between the glandular centres were also determined. It was observed that the prostatic epithelium was quickly reduced in thickness after castration, to one half at day 2. Decline of the fractional amount of the lumen was slower; it also reached below the 10% level at day 30. The amount of interacinar tissue first increased at 12 hours by one third, but from then on decreased to one third of the normal amount. The 'thickness' of the stroma almost doubled, which was probably due to the sum of the simultaneous marked decline in the diameter of the tubules to one third of the original and the less striking reduction to two thirds of the mean distance between the glandular centres. The morphometrical method ensured the acquisition of a quantitative insight into the tissue processes involved in prostatic atrophy. Calculation of the fractional weights was regarded as especially invaluable, inasmuch as a growing body of evidence has been accumulated in favour of the crucial role of stromal-epithelial interactions in the differentiation, and growth, of the prostate.

Animals↗

PubMed1993

[Molecular biological mechanisms in prostatic neoplasms].

An overview is given on three topics of prostate carcinoma: 1. New data on genetic factors in the pathogenesis, 2. molecular activation mechanisms in metastasis and 3. endocrine dedifferentiation during the course of the disease causing androgen independent state. Recent epidemiological analyses have clearly shown, that a specific part of prostate cancer is inherited. By DNA-interphase analyses specific allelic losses have been demonstrated. Metastatic progression is both associated with oncogene ras activation and chromosomal deletions. Endocrinological dedifferentiation cannot be simply explained by an overgrowth by androgen-receptor negative tumor cells, but by a more complex deregulation with strong influences by stromal-epithelial interactions. Downregulation of the promoter region of the androgen receptor may play a crucial role in the development of "endocrine deafness".

Chromosome Deletion↗

PubMed1994

Hormonal regulation of insulin-like growth factor II and insulin-like growth factor binding protein expression by breast cancer cells in vivo: evidence for stromal epithelial interactions.

Insulin-like growth factors (IGFs) I and II are potent mitogens for breast cancer cells. Their proliferative activity is likely to be influenced by their binding proteins (IGFBPs), a family of newly identified proteins. We report here on the in vivo hormonal regulation of mRNAs for IGF-II and IGFBPs in the N-nitrosomethylurea-induced rat mammary tumor, a well-established model of hormone-responsive mammary cancer. IGF-II mRNA levels tended to decrease in regressing tumors following ovariectomy, and they markedly increased upon reactivation of tumor growth with hormone repletion. Ovariectomy induced a drastic increase in IG-FBP-6 mRNA which was reversible with hormone repletion. Similar but more modest changes were observed with IGFBP-2 mRNA. In contrast, IGFBP-3 and IGFBP-4 mRNAs tended to decrease with ovariectomy and increase with hormone repletion. These latter effects, however, were modest, variable, and not statistically significant. In situ hybridization analysis revealed that IGF-II, IGFBP-5, and IGFBP-6 mRNAs were localized in the stromal component of the tumor, whereas IGFBP-2 mRNA was expressed by epithelial cells. We conclude that hormonal regulation of IGFBP expression is heterogeneous, thus suggesting divergent biological functions for these peptides. Our data also emphasize the importance of potential stromal-epithelial interactions in the control of breast cancer cell proliferation by IGFs.

Animals↗

PubMed1994

Biomarkers associated with prostate cancer progression.

In search of biomarkers that predict of human prostate cancer progression, we hypothesized that these markers must be expressed in prostatic epithelial cells during multi-step prostate carcinogenesis. Since both genetic and epigenetic factors have been implicated in human prostate cancer development, two osseous-metastatic experimental models were developed in our laboratory, one based on gene transfection and the other on stromal-epithelial interaction studies. In the genetic model, PC-3 cells transfected with point-mutated c-erbB-2/neu oncogene subsequently acquired the potential to metastasize from the prostate to soft tissues and the skeleton. In the epigenetic model, sublines derived from the parental androgen-dependent LNCaP cell line metastasized from the primary tumor to the lymph node and bone. Cells with known lineage relationships were cloned from both the primary and the metastatic tumors and were characterized extensively using cellular, biochemical, immunohistochemical, and molecular techniques. Relevant stage-specific biomarkers associated with prostate cancer progression in these two models were defined and used to evaluate human prostate tissues obtained from the clinic. In this communication, we focused our discussion on the potential importance of c-erbB-2/neu oncogene, vimentin, hepatocyte growth factor/scatter factor and its receptor, c-met oncogene, tumor angiogenesis and neuroendocrine factors as biomarkers for human prostate cancer progression.

Animals↗

PubMed1995

[Studies on the mechanisms of action of fibroblast growth factors in stromal cells in hyperplastic human prostate].

Stromal-epithelial cell interaction is very important for the development of human benign prostatic hyperplasia (BPH). Growth factors and their receptors in the prostate are thought to mediate the cell communication and play some roles in the development of BPH. Among many growth factors, fibroblast growth factor (FGF) family members have received the most intensive study, and mRNAs for acidic FGF (aFGF), basic FGF (bFGF) and keratinocyte growth factor (KGF) have been identified in rat or human prostate. However, synthesis sites and roles of them in stromal-epithelial cell interaction remain to be undefined. In the present study, to define the mechanisms for the regulation of prostatic cell growth by stromal cells in human BPH, we established the method for isolation and culture of epithelial cells as well as stromal cells from human BPH tissue. Using these primary cultured prostatic cells, we evaluated the effects of stromal cell conditioned medium (SCM) and stromal cell extract (SCE) on the growth of stromal cells and epithelial cells by [3H]-thymidine incorporation assay. We also examined the expression of mRNAs for aFGF, bFGF, KGF, FGF receptor 1 (FGFR1) and FGFR2 in epithelial and stromal cells using Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) analysis. As the results, both SCM and SCE stimulated the growth of stromal cells, and the growth promoting effects of them to stromal cells were completely suppressed by anti-bFGF neutralizing antibody, but not by anti-aFGF neutralizing antibody at all. SCM also stimulated the growth of epithelial cells. The growth promoting effect of it to epithelial cells was not completely suppressed by anti-bFGF neutralizing antibody, and not by anti-aFGF neutralizing antibody at all. Furthermore, RT-PCR analysis demonstrated the expression of mRNAs for bFGF, KGF and FGFR1 in stromal cells and that of FGFR2 in epithelial cells. These findings suggest that bFGF produced by stromal cells acts on stromal cells through FGFR1 by an autocrine mechanism, KGF produced by stromal cells acts on epithelial cells through FGFR2 by a paracrine manner in human BPH. These mechanisms for the regulation of cell growth by stromal cells were thought to contribute to the development of human BPH.

Cell Division↗

PubMed1988

Effect of aging on kinetic parameters of 5 alpha-reductase in epithelium and stroma of normal and hyperplastic human prostate.

Altered 5 alpha-dihydrotestosterone (DHT) metabolism and stromal-epithelial cell interactions are two factors hypothesized to explain the development of benign prostatic hyperplasia (BPH). Furthermore, the development of BPH is clearly age dependent. Therefore, we studied the age-dependent alteration of 5 alpha-reductase, the enzyme that catalyzes the irreversible conversion of testosterone to DHT in epithelium and stroma of the human prostate. For this purpose kinetic parameters [Km Vmax] of 5 alpha-reductase were determined separately in epithelium and stroma of normal prostatic tissue (NPR) from 5 and BPH tissue from 20 men, and the results were correlated with the age of the donors (15-86 yr). The mean Km in epithelium [NPR, 14.3 +/- 1.8 (+/- SE); BPH, 29.5 +/- 2.7 nmol/L] was significantly (P less than 0.0001) lower than that in stroma (NPR, 78.4 +/- 8.5; BPH, 185.8 +/- 13.6 nmol/L). The mean Vmax in epithelium [NPR, 23.8 +/- 3.9 (+/- SE); BPH, 27.9 +/- 3.0 pmol/mg protein.h] was significantly (P less than 0.0001) lower than that in stroma (NPR, 68.3 +/- 4.4; BPH, 173.8 +/- 12.2 pmol/mg protein.h). The DHT-forming index (Vmax/Km) in NPR epithelium [1.6 +/- 0.2 (+/- SE)] was significantly (P less than 0.01) higher than that in NPR stroma (0.9 +/- 0.1), while in BPH the DHT-forming index was nearly identical in epithelium (1.1 +/- 0.1) and stroma (1.0 +/- 0.1). The Km values in epithelium and stroma both correlated positively (P less than 0.01) with age, but the Vmax values correlated positively with age (P less than 0.0001) only in stroma. The DHT-forming index decreased significantly with age in epithelium (P less than 0.01), but remained constant in stroma. These results indicate that there is a nonuniform age-dependent alteration of Km and Vmax in epithelium and stroma of the human prostate independent of the presence of BPH, which might have an impact on the conversion rate of testosterone to DHT with advancing age.

Adult↗