Characterization and co-culture of novel nontransformed cell lines derived from rat endometrial epithelium and stroma

Summary Normal and neoplastic growth of epithelial cells depends on mutual interactions between epithelial and stromal cells. As a tool for the study of the underlying molecular mechanisms, we have developed temperature-sensitive, nontransformed cell lines derived from rat uterine epithelium and stroma by transfecting primary cultures with a temperature-sensitive mutant of the SV40 large T antigen. The epithelial and stromal cell lines obtained shared relevant morphological characteristics with the primary cells from which they were derived. Immunocytochemical analysis showed that the epithelial cell lines expressed the intermediate filament cytokeratin, whereas the stromal lines expressed the intermediate filament vimentin. Alkaline phosphatase activity was present in all cell lines examined. All cell lines were anchorage dependent and did not form foci. One epithelial cell line expressed oxytocin mRNA, a gene product recently shown to be highly expressed in vivo in the uterine epithelium at term. If grown on Matrigel, this cell line formed domelike structures, a further characteristic of its differentiated phenotype. In an attempt to reconstitute an endometrium in vitro, epithelial cells were seeded on top of a layer of stromal cells. Paraffin cross sections showed that this in vitro system consisted of a bilayer structure. Four to five cuboidal epithelial cells were typically anchored atop one stromal cell, forming an endometriumlike tissue. The present in vitro system should provide a useful model for further studies on endometrial functions and epithelial/stromal cell interactions at a molecular level.     

Human papilloma virus E6/E7 genes can expand the lifespan of human corneal fibroblasts

Summary Human corneal fibroblasts were infected with a retroviral delivery vector containing the E6 and E7 genes from human Papilloma virus type 16 in order to produce cell lines that have an expanded lifespan in culture. Morphologically, some of the trasfected corneal fibroblast lines appeared to have the normal spindle-shape morphology of diploid fibroblasts, whereas other lines appeared to have a more elongated morphology. All the cell lines were anchorage-dependent. Cells that had a normal morphology grew at a rate similar to normal diploid human corneal fibroblasts and had a population doubling time of 48 h. All E6/E7 expressing cell lines, regardless of morphology, produce types I, III, and V collagen, at levels similar to those observed in the parent corneal diploid fibroblast. These corneal fibroblast lines will be a usefulin vitro system to study collagen expression and fibril formation, as well as normal stroma development. These results also demonstrate that the use of E6/E7 genes to expand a cell’s lifespan can be a powerful tool because it does not appear to alter either the growth rate of the cell or collagen expression.     

Synthesis of stromal glycosaminoglycans in response to injury

Our goal is to examine the synthesis and deposition of corneal glycosaminoglycans (GAGs) in response to a wound created by the insertion of porous discs into stromal interlamellar pockets. The disc and the surrounding stromal tissue were assayed and compared to contralateral control stroma and to sham operated corneas at 14,42, and 84 days. The tissue and/or discs were removed and labeled with ³⁵S-sulfate for 18 h; GAGs were extracted with 4 M guanidine–HCl. Extracts were chromatographed on Q-Sepharose columns, bound proteoglycans were eluted with a linear salt gradient, and radioactive fractions were analyzed. Total GAG content was determined colorimetrically, using dimethylmethylene blue. Specific GAGs were determined using enzymatic digestion with selective polysaccharide lyases and protein cores were examined using SDS–PAGE. The nonbound fractions from the chromatography were assayed for TGF-β using Western blot analysis and for hyaluronic acid using an ¹²⁵I-radiometric assay. Specific GAGs were localized 42 days after the disc had been implanted in the stroma. The placement of the discs into the stroma resulted in a decrease in the total amount of GAG. However, the ratio of dermatan-chondroitin sulfate and heparan sulfate to keratan sulfate increased in the surrounding tissue and disc. Hyaluronic acid was elevated at day 14 in the surrounding tissue, and not until day 84 in the disc. Western blot analysis of surrounding tissue extracts revealed forms of TGF-β that migrated with an apparent molecular mass of 63 and 43 kDa. The results indicate that the insertion of discs into interlamellar pockets causes changes in the sulfation and proportion of the glycosaminoglycans in the surrounding tissue and the disc. These changes are coincident with the appearance of TGF-β. After 84 days, the population of glycosaminoglycans in the disc begins to resemble the surrounding stroma. This model will allow us to examine further the synthesis and deposition of proteins following an extensive wound in which cells must migrate to the wound site and then undergo extensive remodeling. © 1995 Wiley-Liss, Inc.     

Mesenchymal stem cells in tumor development

Mesenchymal stem cells (MSCs) are multipotent progenitor cells that participate in the structural and functional maintenance of connective tissues under normal homeostasis. They also act as trophic mediators during tissue repair, generating bioactive molecules that help in tissue regeneration following injury. MSCs serve comparable roles in cases of malignancy and are becoming increasingly appreciated as critical components of the tumor microenvironment. MSCs home to developing tumors with great affinity, where they exacerbate cancer cell proliferation, motility, invasion and metastasis, foster angiogenesis, promote tumor desmoplasia and suppress anti-tumor immune responses. These multifaceted roles emerge as a product of reciprocal interactions occurring between MSCs and cancer cells and serve to alter the tumor milieu, setting into motion a dynamic co-evolution of both tumor and stromal tissues that favors tumor progression. Here, we summarize our current knowledge about the involvement of MSCs in cancer pathogenesis and review accumulating evidence that have placed them at the center of the pro-malignant tumor stroma.     

Understanding the role of stromal fibroblasts in cancer progression

The major cellular components of tumor microenvironment, referred to as the cancer stroma, are composed of cancer-associated fibroblasts that support tumor epithelial growth, invasion and therapeutic resistance. Thus when we speak of developing therapies that address tumor heterogeneity it is not only a matter of different mutations within the tumor epithelia. While individual mutations in the stromal compartment are controversial, the heterogeneity in fibroblastic population in a single tumor is not up for debate. Cooperative interaction among heterotypic fibroblasts and tumor cells contribute to cancer progression. Therefore to tackle solid tumors, we need to understand its complex microenvironment. Here we review some seminal developments in the field of tumor microenvironment, mainly focusing on cancer-associated fibroblast.     

Isolation of Primary Myofibroblasts from Mouse and Human Colon Tissue

The myofibroblast is a stromal cell of the gastrointestinal (GI) tract that has been gaining considerable attention for its critical role in many GI functions. While several myofibroblast cell lines are commercially available to study these cells in vitro, research results from a cell line exposed to experimental cell culture conditions have inherent limitations due to the overly reductionist nature of the work. Use of primary myofibroblasts offers a great advantage in terms of confirming experimental findings identified in a cell line. Isolation of primary myofibroblasts from an animal model allows for the study of myofibroblasts under conditions that more closely mimic the disease state being studied. Isolation of primary myofibroblasts from human colon tissue provides arguably the most relevant experimental data, since the cells come directly from patients with the underlying disease. We describe a well-established technique that can be utilized to isolate primary myofibroblasts from both mouse and human colon tissue. These isolated cells have been characterized to be alpha-smooth muscle actin and vimentin-positive, and desmin-negative, consistent with subepithelial intestinal myofibroblasts. Primary myofibroblast cells can be grown in cell culture and used for experimental purposes over a limited number of passages.     

Multitargeted therapies for multiple myeloma

Multiple myeloma (MM) comprises 1% of all malignancies and 10% of all hematological malignancies. MM is a malignancy of plasma cells in the bone marrow where complex and dynamic interactions with the bone marrow microenvironment lead to tumor progression, skeletal destruction and angiogenesis. Despite the discovery of several novel treatments against MM, including the proteasome inhibitor bortezomib, it is considered to be an incurable disease with an average 4–5 years overall survival.     

Over-expression of fibroblast activation protein alpha increases tumor growth in xenografts of ovarian cancer cells

Fibroblast activation protein alpha （FAPα） is a 95-kDa serine protease of post-prolyl peptidase family on cell surface. FAPoL is widely expressed in tumor microenviron- ment. The wide spread association of FAPα expression with cancer suggests that it has important functions in the disease. However, the nature of FAPα＇s roles in cancer cell activity is not well-determined. It has been showed that FAPα silencing in SKOV3 cells induces ovarian tumors but significantly reduces tumor growth in a xenograft mouse model. To further determine the role of FAPoL in epithelial ovarian cancer cells, SKOV3-FAPα and HO8910-FAPα cell lines, which over-expressed FAPα stably, were con- structed and then their biological behaviors were investi- gated. It was found that FAPoL promoted ovarian cancer cell proliferation, drug resistance, invasiveness, and migra- tion in vitro. Immunochemistry assay showed that FAPα significantly facilitated tumor growth in xenograft tumor tissues. These results suggested that FAPα might directly promote tumor growth and invasiveness in ovarian cancer cells.     

Effects of Salicylic Acid on the Structure of Second Leaves of Hordeum Vulgare L.

The structure and ultrastructure of the second leaves of 10-d-old barley plants (Hordeum vulgare L. cv. Alfa) was investigated after long-term treatment with salicylic acid (SA) in concentrations of 0.1, 0.5 and 1.0 mM. The treatment induced: 1) suppressed bulliform cells formation in the adaxial epidermis (1.0 mM SA); 2) reduction of apoplast in the mesophyll (0.5 and 1.0 mM SA); 3) formation of invaginations (0.1 and 0.5 mM SA) and proliferations (0.5 mM SA); and 4) thylakoid destruction and coagulation of the stroma (1.0 mM SA).