ABSTRACT
Fexofenadine is useful in various allergic disease treatment.However,the pharmacokinetic variability information and quantitative factor identification of fexofenadine are very lacking.This study aimed to verify the validity of previously proposed genetic factors through fexofenadine population pharmaco-kinetic modeling and to explore the quantitative correlations affecting the pharmacokinetic variability.Polymorphisms of the organic-anion-transporting-polypeptide(OATP)1B1 and 2B1 have been proposed to be closely related to fexofenadine pharmacokinetic diversity.Therefore,modeling was performed using fexofenadine oral exposure data according to the OATP1B1-and 2B1-polymorphisms.OATP1B1 and 2B1 were identified as effective covariates of clearance(CL/F)and distribution volume(V/F)-CL/F,respectively,in fexofenadine pharmacokinetic variability.CL/F and average steady-state plasma con-centration of fexofenadine differed by up to 2.17-and 2.20-folds,respectively,depending on the OATP1B1 polymorphism.Among the individuals with different OATP2B1 polymorphisms,the CL/F and V/F differed by up to 1.73-and 2.00-folds,respectively.Ratio of the areas under the curves following single-and multiple-administrations,and the cumulative ratio were significantly different between OATP1B1-and 2B1-polymorphism groups.Based on quantitative prediction comparison through a model-based approach,OATP1B1 was confirmed to be relatively more important than 2B1 regarding the degree of effect on fexofenadine pharmacokinetic variability.Based on the established pharmacokinetic-pharmacodynamic relationship,the difference in fexofenadine efficacy according to genetic poly-morphisms of OATP1B1 and 2B1 was 1.25-and 0.87-times,respectively,and genetic consideration of OATP1B1 was expected to be important in the pharmacodynamics area as well.This population phar-macometrics study will be a very useful starting point for fexofenadine precision medicine.
ABSTRACT
BACKGROUND: The normal functions of the cell cycle inhibitor p16INK4a are frequently inactivated in many human cancers. Over 80% of hepatocellular carcinoma (HCC) cases lack a functional p16/Rb pathway. p16/Rb pathway, as well as p53 pathway, is considered as one of key components of tumor suppression. METHODS: To study the roles of p16INK4a in HCC, a stable cell line expressing exogenous p16 was generated from SNU-449 hepatocellular carcinoma cells lacking endogenous p16, and suppression subtractive hybridization (SSH) was performed in parallel with the control cells. RESULTS: 1) SSH identifies fibronectin (FN1), crystallin alphaB (CRYAB), Rac1, WASP, RhoGEF, and CCT3 as differentially-expressed genes. 2) Among the selected genes, the up- regulation of FN1 and CRYAB was confirmed by Northern blot, RT-PCR and by proteomic methods. CONCLUSION: These genes are likely to be associated with the induction of stress fiber and stabilization of cytoskeleton. Further studies are required to clarify the possible role of p16 in the signal transduction pathway.