Enhancement of tumorigenicity of human breast adenocarcinoma cells in nude mice by matrigel and fibroblasts.

The failure of MCF7 cells to induce the formation of tumours after sub-cutaneous inoculation into athymic nude mice can be obviated by the simultaneous injection of an extract of basement membrane proteins (matrigel). Tumour growth is promoted and the latency period is low (2 to 4 weeks). In the absence of matrigel, the simultaneous inoculation of fibroblasts and MCF7 cells also resulted in the development of tumours, but with a longer latency period (about 2 months). The tumorigenic synergy between matrigel and fibroblasts was evidenced by co-inoculating MCF7 cells MDA-MB 231 cells with fibroblasts and matrigel. This co-inoculation decreased the delay of appearance of the tumours and/or accelerated the tumour growth, depending upon the number of fibroblasts injected. Repeated injections of fibroblasts conditioned medium, at the site of inoculum of tumour cells also enhanced tumour growth, suggesting the involvement of soluble factors secreted by fibroblasts. Histologically, tumours induced by co-inoculation of tumour cells and fibroblasts contained more stromal structures including vimentin-positive cells, fibronectin and interstitial collagens. These data suggest that human tumours may be reconstituted and grown in athymic nude mice using basement membrane components and fibroblasts as inductors

Significant variation in mouse-skin aryl hydrocarbon hydroxy- lase inducibility as a function of the hair growth cycle.

An easy, rapid and improved technique for homogenizing whole skin is described. This technique consists of reducing skin to a powder in liquid N2 by using a metallic mortar, and homogenizing the powder in a Potter-Elvehjem tube. Using this homogenizing method, we have shown that skin AHH activity in C57BL/6K and C3H/Ico mice can be induced by i.p. injected or topically applied methylcholanthrene during a defined period of the hair growth cycle, i.e. between the 8th and 14th days after depilation (Stage 6 of the anagen period). In each experimental model, there is an optimal methylcholanthrene concentration which yields a maximum induction. Topical methylcholanthrene is also responsible for a smaller aryl hydrocarbon hydroxylase (AHH) induction when the chemical is applied the same day that the club hairs are plucked. On the other hand, skin AHH activity is never induced by methylcholanthrene in DBA/2J mice, a genetically non-responsive strain. No clear-cut segregation of skin AHH inducibility levels is found among the offspring from the back-cross between (C57BL/6J X DBA/2J)F1 and non-inducible DBA/2J mice

Abnormal gene expression in skin fibroblasts from a Hutchinson-Gilford patient.

We had the opportunity to investigate a new case of Hutchinson-Gilford progeria, a rare disease commonly regarded as a model in the study of aging. Two strains of fibroblasts (strains 1 and 2) were derived from two pieces of a skin biopsy. These two populations multiplied as normal cells at low population doubling level but senesced rapidly and stopped proliferating after 14 or 15 population doubling levels. Interestingly, an unusual pattern of growth in clusters was observed for strain 1. The level of collagen and noncollagen protein synthesis of both strains of affected fibroblasts was similar to that of normal fibroblasts as determined by [3H]proline incorporation measurement and was similarly affected by varying serum concentrations. The pattern of the main types of newly synthesized collagen polypeptides analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis was similar in normal and progeria cells. The steady-state level of mRNAs coding for macromolecules of the extracellular matrix did not provide any differences between affected and control fibroblasts except for a strong increase of elastin and of alpha 1 and alpha 2 type IV procollagen mRNA mainly in strain 1 and less marked in strain 2. Interestingly, senescent progeria fibroblasts exhibited a reduced level of all the tested mRNAs, whereas collagen type IV and elastin mRNAs remained elevated. As suggested by immunofluorescence and immunoblotting studies, the increased amount of type IV mRNAs was paralleled by an enhanced production of type IV collagen by fibroblasts in vitro. Histologic examination of the skin revealed a superabundant network of abnormal elastic fibers in the reticular dermis and a thickening of basement membranes. The relationship between these alterations and aging in progeria is discussed

Low Intensity Electromagnetic Fields Produce a Wave of Calcium in the Fibroblasts

Human fibroblasts display a Ca2+ wave after irradiation with an electromagnetic field (EMF) of low intensity (100 to 900 microT) as seen by LASER confocal microscopy and excitation of Fluo 3. The number of excited cells is proportional to the intensity of EMF between 100 and 900 microT. Cellular activation by a dialysable serum factor is required to induce the Ca2+ wave. It also depends on extracellular Ca2+ and active tyrosine kinases and phospholipase C gamma

Combined 10pter-->P11 and 18pter-->Q11 Trisomy in a 7-Year-Old Child

We report a severely mentally retarded, dysmorphic girl aged 7 years with a 47,XX, +der(18), t(10;18)(p11.2;q11.2)mat. The phenotype of our patient is compared with 6 cases of trisomy 10p and 10 cases of trisomy 18q- from the literature. The short trisomic segment 10pter-10p11 appears to affect more the phenotype than the trisomic segment 18qter-q11

Epitope mapping of type VII collagen. Identification of discrete peptide sequences recognized by sera from patients with acquired epidermolysis bullosa.

Epidermolysis bullosa acquisita (EBA) is an acquired blistering skin disease characterized by the presence of IgG autoantibodies that recognize type VII (anchoring fibril) collagen. In this study, we have mapped the antigenic epitopes within the type VII collagen alpha chain by Western immunoblotting analysis with sera from 19 patients with EBA, using bacterial collagenase- or pepsin-resistant portions of type VII collagen and a panel of 12 recombinant fusion proteins corresponding to approximately 80% of the primary sequence of the alpha 1 (VII) collagen polypeptide. These studies identified four major immunodominant epitopes localized within the amino-terminal, noncollagenous (NC-1) domain. In addition to EBA, sera from three patients with bullous systemic lupus erythematosus (BSLE) were tested. The pattern of epitopes recognized by these sera were similar to those noted with EBA, suggesting that the same epitopes could serve as autoantigens in both blistering conditions. In contrast, sera from healthy controls or from patients with unrelated blistering skin diseases did not react with type VII collagen epitopes. Collectively, the results indicate that the immunodominant epitopes in EBA and BSLE lie within the noncollagenous regions of type VII collagen. The precise role of the circulating autoantibodies in the pathogenesis of these blistering diseases remains to be elucidated. Conceivably, however, such antibodies could disrupt the assembly of type VII collagen into anchoring fibrils and/or interfere with their interactions with other extracellular matrix molecules within the cutaneous basement membrane zone