Cathepsins D, B, and L in transformed human breast epithelial cells.

To investigate the regulation of lysosomal enzymes during carcinogenesis, we measured cathepsins (Cats) D, B, and L in MCF-10F, which is a human breast epithelial cell line, and cells evolved after treatment with carcinogen and transfected with c-Ha-ras oncogene. The clones used in this study, MCF-10FTras, D3, D3-1, and D3-1Tras, expressed no estrogen receptors and gradually increased invasive potential, while oncogene-transfected lines were also tumorigenic in SCID mice [16, 19]. Cats D, B, and L were determined in the cells and in cell media using enzyme-linked immunosorbent assay (ELISA), specific enzyme activity measurements, and immunocytochemistry. The major intra- and extracellular lysosomal proteinase in these cells was Cat D (30-180 pm/mg), followed by Cat B (2-10 pm/mg) and Cat L (1-5 pm/mg). An inverse relationship between intracellular Cat D levels and invasive potential of carcinogen-treated and c-Ha-ras oncogene-transfected cell lines was observed. No significant changes in extracellular concentration of Cat D precursor in this series of cell lines was observed. Intracellular levels of Cats B and L were unchanged or slightly lower in carcinogen-treated D3 and D3-1 cells, as well as in MCF-10FTras. On the other hand, in D3-1Tras cell line, evolving from c-Ha-ras transfected D3-1 line, 3.5 fold and 4.4 fold increases in Cat B and Cat L, respectively, but a 2 fold decrease in Cat D, were observed compared to the parental cell line. Immunocytochemical staining showed a granular, polarized perinuclear and cytoplasmic staining of cathepsins in all cell lines. Cysteine proteinases stained more frequently and more intensely in D3-1Tras compared to other lines, confirming the immunochemical assays. We hypothesize that several molecular events, caused by a carcinogen and an oncogene such as c-Ha-ras, are needed to increase Cat B and Cat L, but not Cat D, expression. Therefore, the cysteine and aspartic lysosomal proteinases are differentially expressed in the breast cell lines with more invasive phenotype.

Cathepsins D, B and L in breast carcinoma and in transformed human breast epithelial cells (HBEC).

An increased expression of lysosomal enzymes, cathepsin (Cat) D, Cat B and Cat L, was observed in various human tumours and after in vitro cell transformation. To establish possible co-ordination in their expression, all three cathepsins were determined in human breast tumours and in transformed human breast epithelial cells (HBEC). In breast carcinoma (n = 120) all three cathepsins, determined immunochemically and by enzymatic activity, were increased compared to normal breast tissues. The activities, correlated with the corresponding protein masses for Cat D (r = 0.77, p < 0.01), but not for Cat B and Cat L. Significant increase in Cat B activity was observed in stage II compared to stage I tumours, and Cat L activity in stage III compared to stage II tumours, but no significant correlation of cathepsin protein with tumour stage (TNM) was established. No significant correlation between Cat D and the cysteine cathepsins B and L was observed. Similarly, Cat D, Cat B and Cat L levels did not correlate in the in vitro system, e.g. in the five transformed HBEC, such as evolved after dimethylbenz(a)anthracene treatment and c-Has-ras oncogene transfection of diploid MCF-10F cell line (Calaf et al., 1993). Transformed cells showed increased anchorage-independent growth and invasive capability (MCF-10 < MCF-10FTras < D3 < D3-1 < D3-1Tras). The intracellular level of Cat D was not related to cell invasiveness, while total cellular Cat B and Cat L increased 13 fold and 4 fold, respectively, in the most invasive cell line, D3-1Tras compared to MCF-10F.(ABSTRACT TRUNCATED AT 250 WORDS)

Flexibilized gelatin film-based artificial skin model: I. Preparation and properties of the films.

A method was developed to prepare a simple, flexibilized gelatin film-based artificial skin model. The films are tough, adhere to open wounds spontaneously, are permeable to body fluids, and can release incorporated bioactive compounds over 4-5 days.

Flexibilized gelatin film-based artificial skin model: II. Release kinetics of incorporated bioactive molecules.

Any delivery system for bioactive molecules should have the ability to release the compound in question in a reproducible and predictable way over a certain period. For artificial skin models that are designed to enhance healing by the use of growth factors, this requirement poses another problem: the design of a delivery method that can provide a realistic assessment of the release kinetics. This means that the design should "mimic" conditions encountered in an open wound, i.e., only a certain part of the film can face the wound, from which it can absorb wound fluid that will dissolve the incorporated bioactive molecule and bring it to the open wound. Such a system has been developed and the release of 125I-labelled insulin, incorporated into flexibilized gelatin films, has been determined. The details of this study follow.

Cell-specific phosphorylation of H1 histone subtypes among different Chinese hamster cell lines in interphase.

The phosphorylation of H1 histone subtypes was studied in 3 Chinese hamster cell lines (CHO, V79, and CHW). Chromatographic resolution of H1 subtypes showed that all 3 cell lines contained 1 homologous (coeluting) H1 subtype (CHO-1, V79-1, and CHW-1) while V79 and CHW cells contained 2 additional H1 subtypes not found in CHO cells (V79-2,3 and CHW-2,3). N-Bromosuccinimide cleavage of 32P-labeled H1 subtypes demonstrated that all V79 subtypes were phosphorylated in both the NH2- and COOH-terminal regions during interphase while CHO-1 was phosphorylated only in the COOH-terminal region. Tryptic phosphopeptide fractionations, using 2 sequential electrophoretic steps on paper, demonstrated qualitative differences in the 32P-labeled peptides from the 7 H1 subtypes of the 3 cell lines. For example, CHO-1 differed from its V79-1 homologue by 1 phosphopeptide and from its CHW-1 homologue by 3 phosphopeptides. Phosphopeptide differences were also observed among the H1 subtypes of both V79 and CHW cells. The results demonstrate that Chinese hamster cell lines phosphorylated H1 histone subtypes differently during interphase and that there is no rigorous functional connection between the phosphorylation of the NH2-terminal region of 1 or all H1 histone subtypes and the initiation of mitosis in Chinese hamster cells.