ABSTRACT
A variant of the serpin squamous cell carcinoma antigen (SCCA) has been identified as a hepatitis B virus binding protein and high expression of SCCA has recently been found in hepatocarcinoma. Since HBV is involved in liver carcinogenesis, experiments were carried out to examine the effect of HBV preS1 envelope protein on SCCA expression. Surface and intracellular staining for SCCA was assessed by FACS analysis. Preincubation of HepG2 cells and primary human hepatocytes with preS1 protein or with preS1(21-47) tetrameric peptide significantly increased the surface expression of SCCA, without modification of its overall cellular burden, suggesting a surface redistribution of the serpin. An increase in HBV binding and internalization was observed after pre-incubation of the cells with preS1 preparations, compared to cells preincubated with medium alone. Pretreatment of cells with DMSO, while not influencing SCCA basal expression, was responsible for an increase in the efficiency of HBV internalization and this effect was additive to that obtained after incubation with preS1 preparations. In conclusion, the HBV preS1(21-47) sequence is able to induce overexpression of SCCA at the cell surface facilitating virus internalization, while the increased efficiency of HBV entry following DMSO addition is not mediated by SCCA.
Subject(s)
Antigens, Neoplasm/genetics , Carcinoma, Squamous Cell/genetics , Gene Expression Regulation, Neoplastic/genetics , Gene Expression Regulation, Viral/genetics , Hepatitis B virus/genetics , Serpins , Antigens, Surface/genetics , Biomarkers, Tumor/genetics , Carcinoma, Squamous Cell/pathology , Cell Line, Tumor , DNA Primers , Flow Cytometry , Humans , Polymerase Chain ReactionABSTRACT
BACKGROUND: Gilbert syndrome as a rule becomes manifest in adolescence or in early adulthood; it may be transferred by the donor to orthotopic liver transplant (OLT) recipients. METHODS: We examined the frequency of Gilbert syndrome in 46 OLT pediatric recipients who had a follow-up of 1 year or more. Diagnostic criteria included unexplained chronic or recurrent unconjugated hyperbilirubinemia; its increase after reduced caloric intake plus prolonged fasting, without changes of the proportion of conjugated bilirubin; and high relative amounts of serum unconjugated bilirubin IXa and prevalence of the monoglucuronide over the diglucuronide. RESULTS: Of the 46 patients, 42 had normal bilirubin values. Only four otherwise healthy OLT recipients showed hyperbilirubinemia and normal conjugated fractions. Liver donors had been four men. Hyperbilirubinemia persisted with a fluctuating pattern for the whole follow-up after OLT in all. Total bilirubin level in blood samples obtained after reduced caloric intake and prolonged fasting became notably higher than basal values, whereas the proportion of conjugated bilirubin remained stable. High relative amounts of unconjugated bilirubin IXa and prevalence of the monoglucuronide over the diglucuronide were found. Finally, DNA from liver donors' lymphocytes was available for one jaundiced and two nonjaundiced patients: tests for abnormalities in the promoter region of the gene for the enzyme bilirubin uridine diphospho-glucuronosyltransferase were in agreement with a diagnosis of GS in the former one, CONCLUSIONS: Gilbert syndrome may have an unusual early presentation in pediatric OLT recipients.
