IFN-λ endocytosis and IFN-λ responsive promoter activation are dependent on cholesterol

Association of IFNL3 rs12979860 and rs8099917 with biochemical predictors of interferon responsiveness in chronic hepatitis C virus infection

BACKGROUND & AIMS

Genetic variations near the interferon lambda 3 gene (IFNL3, IL28B) are the most powerful predictors for sustained virologic response (SVR) in patients with chronic hepatitis C virus (HCV) infection, compared to other biochemical or histological baseline parameters. We evaluated whether the interplay of both IFNL3 polymorphisms rs12979860 and rs8099917 together with non-genetic clinical factors contributes to the predictive role of these genetic variants.

METHODS

The cohort comprised 1,402 patients of European descent with chronic HCV type 1 infection. 1,298 patients received interferon-based antiviral therapy, and 719 (55%) achieved SVR. The IFNL3 polymorphisms were genotyped by polymerase chain reaction and melting curve analysis.

RESULTS

A significant correlation was found between the IFNL3 polymorphisms and biochemical as well as virologic predictors of treatment outcome such as ALT, GGT, cholesterol, and HCV RNA levels. In multivariate regression analysis, IFLN3 SNPs, HCV RNA levels, and the GGT/ALT ratio were independent predictors of SVR. Dependent on the GGT/ALT ratio and on the HCV RNA concentration, significant variations in the likelihood for achieving SVR were observed in both, carriers of the responder as well as non-responder alleles.

CONCLUSIONS

Our data support a clear association between IFNL3 genotypes and baseline parameters known to impact interferon responsiveness. Improved treatment outcome prediction was achieved when these predictors were considered in combination with the IFNL3 genotype.

The interleukin 28B rs12979860 C/T polymorphism and serum cholesterol as predictors of fibrosis progression in patients with chronic hepatitis C and persistently normal transaminases

The interleukin 28B (IL-28B) rs12979860 C/T polymorphism is a predictor of spontaneous and treatment-induced hepatitis C virus (HCV) clearance. The C/C genotype is associated with higher serum cholesterol, predictor of a favorable outcome in chronic hepatitis C. Whether IL-28B polymorphism and serum cholesterol play a role in modulating the history of mild hepatitis C is unknown. To clarify this issue, 93 untreated patients infected with HCV with normal or near-normal transaminases and an initial Ishak staging score ≤1 were investigated retrospectively in the longitudinal study (median histological follow-up of 10 years). An additional confirmatory cohort of 143 patients with chronic HCV infection and abnormal levels of transaminases was evaluated in the cross-sectional study. In the longitudinal study, at the end of follow-up, Ishak staging scores progressed more frequently among carriers of a T/* allele who had a baseline serum cholesterol ≤175 mg/dl than in remaining patients: 6/36 (change ≤0), 15/45 (change 1-2), 6/12 (change ≥3), improvement chi-square P < 0.02, OR 3.1, 95% C.I. 1.3-7.7. In the cross-sectional study, the frequency of patients carrying the T/T genotype or serum cholesterol values ≤175 mg/dl increased starting from those with a staging score ≤2 (36/76, 47.4%), to those with a staging score of 3-4 (26/41, 63.4%) and to those with a staging score of 5-6 (20/26, 76.9%, P < 0.01 for linear trend). In conclusion, the interaction between IL-28B rs12979860 T/T genotype and low serum cholesterol concentration is an independent predictor of a worse disease course among patients infected with HCV with normal or near-normal transaminases.

Antitumor activities of recombinant human interferon (IFN)-λ1 in vitro and in xenograft models in vivo for colon cancer

Interferon (IFN)-λ1, as a newly identified IFN, interacts with the structurally unique IFN-λ1 receptor complex and exhibits antiviral and antiproliferation effects. The major focus of our work was to study the antitumor activities of recombinant human IFN-λ1 (rhIFN-λ1) in vivo and in vitro. The MTT analysis showed that rhIFN-λ1 inhibited the proliferation of HCT116 cells in a dose-dependent manner, but with a less efficacy in HT29 cells than HCT116 cells. IFN-λ1 also activated the STATs and induced apoptosis in both types of cells. In the in vivo study, we found that rhIFN-λ1 suppressed tumor growth in a dose-dependent fashion, with an inhibition rate of 52% of HCT116 (P<0.01) and 56% of HT29 (P<0.01). These results indicate that rhIFN-λ1 could be a new potential IFN reagent for cancer therapy.