Stimulation of retinoic acid of synthesis and turnover of basement membrane in mouse embryonal carcinoma-derived endoderm cells

Retinoic acid syndrome: manifestations, pathogenesis, and treatment

All-trans retinoic acid (ATRA) is a potent differentiation agent that is effective therapy in acute promyelocytic leukaemia. Although ATRA is generally well tolerated, some patients develop retinoic acid syndrome. This syndrome is manifested by unexplained fever, weight gain, respiratory distress, interstitial pulmonary infiltrates, pleural and pericardial effusion, episodic hypotension, and acute renal failure. However, if identified early enough, effective therapy can be administered. This chapter discusses the clinical aspects and pathogenesis of retinoic acid syndrome.

Simultaneous induction of matrix metalloproteinase-9 and interleukin 8 by all-trans retinoic acid in human PL-21 and NB4 myeloid leukaemia cells

All-trans retinoic acid (ATRA) has been shown to induce differentiation of human acute promyelocytic leukaemia (APL) cells and eventual elimination of the malignant clone. Matrix metalloproteinase-9 (MMP-9) is produced by neutrophils and its expression appears to be linked with myeloid cell differentiation. We investigated effects of ATRA on MMP expression in two human myeloid leukaemia cell lines, PL-21 and NB4. Both cells could differentiate into neutrophils after exposure to ATRA. Both the activity and antigen levels of MMP-9 were much higher in NB4 cells than in PL-21 cells. Stimulation with ATRA significantly increased MMP-9 levels approximately three- to fivefold in both PL-21 and NB4-conditioned media. MMP-9 mRNA levels increased in ATRA-treated cells and was almost in parallel with the increase in MMP-9 activity, suggesting that ATRA induced MMP-9 by activating its gene expression. ATRA can induce interleukin 8 (IL-8) in APL cells. IL-8, chemokine for neutrophils and a potent inducer of MMP-9, was also induced by ATRA in PL-21 cells. However, recombinant IL-8 did not induce MMP-9 expression. In addition, a neutralizing antibody against IL-8 did not inhibit ATRA-induced MMP-9 expression in either cell type. These observations suggest that ATRA can induce both MMP-9 and IL-8, but IL-8 is not involved in ATRA-induced MMP-9 expression. As MMP-9 can truncate and activate IL-8, simultaneous induction of MMP-9 and IL-8 by ATRA could activate leucocytes excessively, causing the hyper-inflammatory events in retinoic acid syndrome.

Retinoic acid synergizes with cyclic AMP to enhance MMP-2 basal promoter activity

Matrix metalloproteinase-2 (MMP-2) degrades basement membrane collagen and its abnormal expression is associated with the enhanced malignancy of metastasizing cancer cells. Retinoids and cyclic AMP analogs have been shown to affect MMP-2 production. Here we demonstrate that the expression of the human MMP-2 gene is enhanced by a synergistic action of retinoic acid (RA) and dibutyryl cyclic AMP (Bt2cAMP). RA also synergizes with Bt2cAMP in enhancing the basal promoter activity when the MMP-2 proximal promoter activity is induced by transient transfection and RA/Bt2cAMP treatment in human fibrosarcoma HT1080 cells. Deletions beyond -315 bp from the transcription initiation site drastically reduce the synergistic enhancement. A search for a cis-element in the MMP-2 proximal promoter shows the presence of a CRE-like sequence (TGACGTCCC) at position -292 bp in the opposite strand. The CRE-like sequence makes complexes with two DNA binding proteins. The results demonstrate that the RA/Bt2cAMP-enhanced transcription of the MMP-2 gene is dependent on the general transcription machinery and suggest that the basal promoter may be a potential target for gene-specific activators.

Decreased biosynthesis of Forssman glycolipid after retinoic acid-induced differentiation of mouse F9 teratocarcinoma cells. Lectin-affinity chromatography of the glycolipid-derived oligosaccharide

Glycolipids synthesized by the mouse teratocarcinoma F9 cells and F9 cells (RA/F9 cells) induced to differentiate by a 3-day treatment with 0.1 microM all-trans-retinoic acid were analyzed. Both F9 cells and RA/F9 cells were incubated in media containing either D-[6-3H]galactose or D-[6-3H]glucosamine; the metabolically-radiolabeled glycolipids were isolated and the oligosaccharides were released from the glycolipids by ozonolysis and alkali fragmentation. From both cells, a single major pentasaccharide was isolated from the mixture of neutral [3H]oligosaccharides by affinity chromatography on a column of immobilized Helix pomatia agglutinin. The structure of this oligosaccharide was analyzed by methylation analysis and specific exoglycosidase treatments and identified as the Forssman pentasaccharide alpha-D-GalpNAc-(1----3)-beta-D-GalpNAc-(1----4)-alpha-D-Galp-(1----4)-b eta-D- Galp-(1----4)-D-Glc. There was a 3-4-fold decreased amount of the Forssman pentasaccharide from RA/F9 cells relative to F9 cells. In contrast, there were no major differences between these cells in the levels of globoside, the precursor to Forssman glycolipid. To investigate the basis for the decline in Forssman glycolipid synthesis upon differentiation, the activity of UDP-D-Gal-NAc:GbOse4Cer alpha-(1----3)-N-acetyl-D-galactosaminyltransferase (Forssman synthase) was determined in extracts of both the F9 and RA/F9 cells. The specific activity of Forssman synthase was approximately 70% lower in differentiated relative to the nondifferentiated cells. These data demonstrated that F9 cells synthesize authentic Forssman glycolipid, and that its expression and the activity of Forssman synthase were decreased following induced cellular differentiation.

In vitro production of Reichert's membrane by mouse embryo-derived parietal endoderm cell lines

We report the isolation of eight independent cell lines from preimplantation mouse embryos, which have a parietal endoderm phenotype. When grown as aggregates, these cell lines produce large amounts of a basement membrane matrix, that contains laminin, nidogen, heparan sulfate proteoglycan, collagen IV, and BM-40. The biosynthetic profiles of all eight cell lines are very similar to parietal endoderm cells in vivo which synthesize Reichert's membrane. The structure of the matrix produced by the parietal endoderm cell lines (PEC lines) resembles more closely Reichert's membrane than the Engelbreth-Holm-Swarm (EHS) tumor in susceptibility to proteolytic degradation. Since these cell lines produce large quantities of basement membrane they will be useful for structural and functional comparison of a Reichert's membrane matrix with the basement membrane produced by the EHS tumor.

Synthesis of extracellular matrix glycoproteins by a differentiated thyroid epithelial cell line

We examined the synthesis of extracellular matrix macromolecules by the differentiated rat thyroid epithelial cell line FRTL-5. As shown by electron microscopy, the extracellular material produced by these cells is deposited at the basolateral surface and focally organized in the form of a basement membrane. Biochemical and biosynthetic studies demonstrated that laminin, type IV collagen, and fibronectin are synthesized and deposited in the culture monolayer. Secretion of fibronectin into the culture medium also occurred. By immunofluorescence we observed some peculiarities in the distribution patterns of the basement membrane glycoproteins; while fibronectin and laminin had an almost superimposable distribution, type IV collagen displayed a rather different pattern. Type IV collagen and laminin localization at sites where extracellular material was detected was confirmed by immuno electronmicroscopy using the protein A-colloidal gold technique. The results indicate that under appropriate culture conditions the differentiated thyroid epithelial cell line FRTL-5 synthesizes, secretes and organizes an extracellular matrix where some basement membrane glycoproteins are present.

Analysis of degradation of the basement membrane protein nidogen, using a specific monoclonal antibody

A monoclonal antibody was produced against purified nidogen extracted from a mouse basement-membrane-producing tumor. This antibody reacted with a determinant on Nd-40, a rod which separates the globular domains of nidogen. Antigenicity depends on intrachain disulfide bonds within this rod. The monoclonal antibody was used to detect nidogen fragments after proteolytic cleavage of isolated nidogen, and nidogen complexed to laminin. The data indicate that thrombin and thermolysin generated very different patterns of degradation, but in both cases no differences were found between isolated and complexed nidogen. In contrast, nidogen in the laminin-nidogen complex was much less degraded by trypsin than isolated nidogen, indicating that an interaction between these basement membrane components reduces the susceptibility of nidogen to trypsin digestion. Immunofluorescent studies, using the monoclonal antibody on sections of the EHS tumor after proteolytic digestion, showed that the retention or disappearance of the Nd-40 determinant correlated with the in vitro digestion pattern of the laminin-nidogen complex.

Antibodies to laminin in preeclampsia

Laminin is a large basement membrane glycoprotein localized in the trophoblast, glomerular basement membrane and in the mesangial matrix of human glomeruli. It promotes the attachment of epithelial cells to basement membrane collagen. We have found that 14 sera from 52 patients with severe preeclampsia or eclampsia contain IgG and IgM antibodies which react with placental and kidney basement membranes. These antibodies were specific for laminin and did not react with other basement membrane proteins. They were able to fix complement. They have been demonstrated by radial immunodiffusion, radioimmunoassay and immunofluorescence blocking studies. In primary cultures they were shown to impair the attachment of trophoblast cells to basement membrane collagen. High levels of circulating immune complexes were detected only in sera from preeclamptic patients with circulating antibodies to laminin. The auto-antibodies to laminin could play a major role in the pathogenesis of severe preeclampsia by impairing the attachment of trophoblast cells to placental basement membranes and by fixation to the glomerular basement membranes and mesangial matrix.

Modulation of type-IV procollagen and laminin production in A431 human squamous epidermoid carcinoma cells by 12-O-tetradecanoylphorbol-13-acetate (TPA) and epidermal growth factor (EGF)

The effect of 12-O-tetradecanoylphorbol-13-acetate (TPA) and epidermal growth factor (EGF) on type-IV-procollagen (basement-membrane collagen) and laminin synthesis, turnover, and secretion was studied in human A431 squamous epidermoid carcinoma cells. Type-IV procollagen and laminin were biochemically and immunologically identified in the medium and cell extracts using immuno-precipitation followed by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. EGF or TPA produced a sixfold increase in type-IV-procollagen and laminin secretion within 2 h; this was accompanied by a three- to fourfold increase in the levels of cell-associated type-IV procollagen and laminin, respectively. The level of type-IV-procollagen and laminin synthesis and secretion remained elevated for at least 16 h after the administration of either EGF or TPA. A combination of EGF and TPA was more effective than either agent alone in promoting the secretion of laminin but not of type-IV procollagen. EGF and/or TPA did not, however, produce a selective increase in the synthesis of collagen and laminin, since total protein synthesis was also increased to the same degree by these agents. As determined by labeling and chase studies, neither EGF nor TPA had any appreciable effect upon type-IV-procollagen or laminin degradation. These results indicate that the synthesis of components associated with the basement membrane in A431 cells (i.e., type-IV procollagen and laminin) can be rapidly modulated by EGF and a tumor promoter, i.e., TPA.(ABSTRACT TRUNCATED AT 250 WORDS)