Mark I. Avigan

Randomized trial of chlorambucil for primary biliary cirrhosis

Twenty-four patients with primary biliary cirrhosis were entered into a prospective, randomized trial of chlorambucil therapy. Thirteen patients received chlorambucil (0.5-4 mg/day) and 11 patients received no therapy; all have been followed for 2-6 yr (mean, 4.1 yr). Two control but no treated patients died. Average serum bilirubin, serum aspartate aminotransferase activities, and albumin levels improved or remained unchanged in treated patients but worsened in controls. Serum alkaline phosphatase levels did not change in either group. Immunoglobulin M levels decreased and became normal in all treated patients but in only 3 control patients. Liver biopsy histology revealed an improvement in inflammatory cell infiltrate in treated patients in comparison with controls, but no significant change in degree of fibrosis or the histologic stage of disease. Side effects of therapy included bone marrow suppression necessitating discontinuation of the drug in 4 patients. These findings indicate that chlorambucil therapy may retard the progression of primary biliary cirrhosis. Whether such therapy will ultimately decrease morbidity and improve survival in this disease can only be demonstrated by large-scale, placebo-controlled trials.

A Short Course of Prednisolone in Chronic Type B Hepatitis: Report of a Randomized, Double-Blind, Placebo-Controlled Trial

Fifteen patients with chronic type B hepatitis were treated with corticosteroids in a randomized, double-blind, placebo-controlled trial lasting 28 days. Ten patients received prednisolone, 60 mg/d for 2 weeks, then 30 mg/d for another 2 weeks; 5 patients received placebo. Serum aminotransferase levels decreased significantly during prednisolone therapy but 4 to 10 weeks after abrupt withdrawal of the drug, they rebounded to levels greater than those before treatment. This exacerbation of disease lasted for several months and was prolonged and symptomatic in 3 patients. Hepatitis B virus levels did not change substantially during treatment. Follow-up examinations showed no improvement in biochemical or serologic features of the disease in any of the 15 patients; follow-up liver biopsies showed a worsening in 4 of 7 treated patients but in 0 of 5 control patients. Thus, a 28-day course of prednisolone produced no beneficial effects in patients with mild-to-moderate chronic type B hepatitis; on the contrary, such treatment may be harmful.

GATA-6 stimulates a cell line-specific activation element in the human lactase promoter

Lactase-phlorizin hydrolase (LPH) synthesis is restricted to differentiated small intestinal enterocytes and is highly regulated during development. Analysis of expression of LPH promoter segments fused with luciferase transfected in Caco-2 cells, a line that uniquely expresses LPH mRNA, mapped an 18-base pair (bp) segment 100 bp upstream of the transcription start site that is required for transactivation. Remarkably, the LPH upstream element (LUE) has no stimulatory activity in both human intestinal and nonintestinal lines in which LPH mRNA is absent. Electrophoretic analysis of sequence-specific DNA-nuclear protein complexes demonstrated the presence of a Caco-2 cell-specific protein(s) (CCP), which is uniformly absent in LPH nonproducer cell lines. Mutational analysis of the LUE demonstrated that bases contained within a GATA consensus motif are critical for both CCP binding and transcription from the LPH promoter. Caco-2 cells express high levels of GATA-6 mRNA in a cell line-specific manner, suggesting that GATA-6 is a CCP that complexes with the LUE. When expressed by a plasmid, GATA-6 transactivated the LPH promoter. The stimulation was abrogated with mutations in the GATA consensus motif as well as mutations in a flanking downstream element. These studies are consistent with an important role of an intestinal GATA binding protein in cell type-specific transactivation of the LPH promoter.Lactase-phlorizin hydrolase (LPH) synthesis is restricted to differentiated small intestinal enterocytes and is highly regulated during development. Analysis of expression of LPH promoter segments fused with luciferase transfected in Caco-2 cells, a line that uniquely expresses LPH mRNA, mapped an 18-base pair (bp) segment 100 bp upstream of the transcription start site that is required for transactivation. Remarkably, the LPH upstream element (LUE) has no stimulatory activity in both human intestinal and nonintestinal lines in which LPH mRNA is absent. Electrophoretic analysis of sequence-specific DNA-nuclear protein complexes demonstrated the presence of a Caco-2 cell-specific protein(s) (CCP), which is uniformly absent in LPH nonproducer cell lines. Mutational analysis of the LUE demonstrated that bases contained within a GATA consensus motif are critical for both CCP binding and transcription from the LPH promoter. Caco-2 cells express high levels of GATA-6 mRNA in a cell line- specific manner, suggesting that GATA-6 is a CCP that complexes with the LUE. When expressed by a plasmid, GATA-6 transactivated the LPH promoter. The stimulation was abrogated with mutations in the GATA consensus motif as well as mutations in a flanking downstream element. These studies are consistent with an important role of an intestinal GATA binding protein in cell type-specific transactivation of the LPH promoter.

Hepatocyte growth factor stimulates invasion across reconstituted basement membranes by a new human small intestinal cell line

Hepatocyte growth factor/scatter factor (HGF/SF) is a protein growth factor whose pleiotropic effects on epithelial cells include the stimulation of motility, mitosis and tubulogenesis. These responses are mediated by the cell surface tyrosine kinase receptor c-met. Because both the cytokine and receptor are found in the gastrointestinal tract, we have studied the effects of HGF/SF on transformed gut epithelial cells which express c-met. Here we describe the response of a new transformed human jejunal epithelioid cell line (HIE-7) to HGF/SF. Morphologically HIE-7 cells are immature. Their epithelial lineage was confirmed by reactivity with the epithelial specific antibodies AE1/AE3, Cam 5.2, Ber-EP4 and anti-EMA and is consistent with their expression of c-met mRNA and protein. In addition, electron microscopic analysis revealed the presence of primitive junctions and rudimentary microvilli, but features of polarization were absent. When grown on reconstituted basement membranes, HIE-7 cells formed closely associated multicellular cord-like structures adjacent to acellular spaces. However, the cells did not mature structurally, form lumen-like structures or express disaccharidase mRNA, even in the presence of recombinant HGF (rHGF). On the other hand, rHGF induced HIE-7 cells to scatter and stimulated their rapid migration in a modified wound assay. To determine whether the motogenic effect caused by rHGF is associated with HIE-7 cell invasiveness across reconstituted basement membranes, a Boyden chamber chemoinvasion assay was performed. rHGF stimulated a 10-fold increase in the number of HIE-7 cells that crossed the basement membrane barrier, while only stimulating a small increase in chemotaxis across a collagen IV matrix, suggesting that the cytokine activates matrix penetration by these cells. rHGF also stimulated the invasion of basement membranes by an undifferentiated rat intestinal cell line (IEC-6) and by two human colon cancer cell lines which are poorly differentiated (DLD-1 and SW 948). In contrast, two moderately well differentiated colon cancer cell lines (Caco-2 and HT-29) did not manifest an invasive response when exposed to rHGF. These results suggest that HGF/SF may play a significant role in the invasive behavior of anaplastic and poorly differentiated gut epithelial tumors.

FUSE-binding protein is developmentally regulated and is highly expressed in mouse and chicken embryonic brain

GAP-43 modulates axon guidance and neuronal plasticity. In vitro, FUSE-binding protein (FBP) binds to a segment of GAP-43 mRNA which regulates the stability of the transcript. FBP has also been shown to bind to a c-myc cis element and regulate transcription. In the current work, analysis of RNA and protein expression indicated that FBP is expressed in a distinct spatial temporal pattern during embryonic development. Expression was particularly high in the brain. In the adult, expression was not detected in most tissues but was still prominent in the brain and teste. This finding is consistent with a dual role of the protein as a single-strand polynucleotide-binding protein.

A newly identified tyrosine kinase is preferentially expressed in the gastrointestinal tract.

We have identified a novel protein tyrosine kinase, cloned from rat intestinal mRNA, which is selectively expressed at high levels in intestinal cells, but is expressed at low or insignificant levels in a variety of other epithelial and non-epithelial organs. Gastrointestinal associated kinase (GASK) mRNA is present at high levels in stomach, small intestine and colon. GASK may play an important role in the growth, differentiation and/or development of the gastrointestinal tract.