Dubin-Johnson syndrome coinciding with colon cancer and atherosclerosis

Characterization of a novel ABCC2 mutation in infantile Dubin Johnson syndrome

BACKGROUND AND AIMS

The Dubin Johnson Syndrome (DJS) occurs mostly in young adults but an early-onset of the disease has been reported in less common forms (Neonatal DJS and Infantile DJS). In this case, the clinical findings are of limit for the DJS diagnosis. Hence, the genetic testing remains the method of choice to provide an accurate diagnosis. In our study, we aimed to perform a genetic analysis for two siblings presented with an intrahepatic cholestasis before the age of 1 year to provide a molecular explanation for the developed phenotype.

PATIENTS & METHODS

A Tunisian family, having two siblings, manifesting signs of a hepatopathy, was enrolled in our study. A molecular analysis was performed, using a panel-based next generation sequencing, supplying results that were the subject of computational analysis. Then, a clinical follow-up was carried out to assess the evolution of the disease.

RESULTS

The genetic analysis revealed the presence of a novel missense c.4179G > T, (p.M1393I) mutation in ABCC2 gene associated with a substitution c.2789G > A (R930Q) in ATP8B1 gene. Predictive results consolidated the pathogenic effect of both variants. These results confirmed the DJS diagnosis in the studied patients. The clinical course of both patients fit well with the benign nature of DJS.

CONCLUSION

We described here a novel ABCC2 mutation associated with a putative ATP8B1 modifier variant. This finding constituted the first report of a complex genotype in DJS. Hence, genetic analysis by a panel-based next generation sequencing permits an accurate diagnosis and the identification of putative variants that could influence the developed phenotype.

Dihydromyricetin reverses MRP2-induced multidrug resistance by preventing NF-κB-Nrf2 signaling in colorectal cancer cell

BACKGROUD

Dihydromyricetin (DMY), a natural flavonoid compound from the leaves of the Chinese medicinal herb Vitis heyneana, has been shown to have the potential to combat chemoresistance by inhibiting Nrf2/MRP2 signaling in colorectal cancer (CRC) cells. However, the precise underlying molecular mechanism and its therapeutic target are not well understood.

PURPOSE

Our study aims to investigate the effects of DMY on multidrug resistance (MDR), and elucidate the underlying mechanisms.

STUDY DESIGN

In vitro, HCT116/OXA and HCT8/VCR cells were employed as our MDR models. The cells were treated with DMY (50 µM) or MK-571 (50 µM) plus oxaliplatin (OXA) (10 µM) or vincristine (VCR) (10 µM) for 48 h. In vivo, we used BALB/c mice as a CRC xenograft mouse model. BALB/c mice were given DMY (100 mg/kg), OXA (5 mg/kg) and DMY (100 mg/kg) combined with OXA (5 mg/kg) via intraperitoneal route every 2 days per week for 4 weeks.

METHODS

We used MTT and colony forming assays to detect DMY's ability to reverse MDR. Flow cytometric analysis was used to detect apoptosis. Immunocytochemistry was used to detect the localization of Nrf2 and NF-κB/p65. Western blot, qRT-PCR and reporter gene assays were employed to measure the protein and gene transcriptional levels (MRP2, Nrf2, NF-κB/p65). Moreover, chromatin immunoprecipitation (ChIP) assay was used to investigate the endogenous promoter occupancy of NF-κB/p65. Finally, immunohistochemistry and TUNEL staining were used to detect protein expression and apoptosis in vivo.

RESULTS

DMY restored chemosensitivity (OXA and VCR) by inhibiting both MRP2 expression and its promoter activity in HCT116/OXA and HCT8/VCR cell lines. Furthermore, DMY could inhibit NF-κB/p65 expression, reducing NF-κB/p65 translocation to the nucleus to silence Nrf2 signaling, which is necessary for MRP2 expression. Overexpressing NF-κB/p65 expression reduced the reversal effect of DMY. In addition, NF-κB/p65 regulated Nrf2 expression by directly binding to its specific promoter region and activating its transcription. Finally, we proved that the combination of OXA and DMY has a synergistic tumor suppression effect in vivo.

CONCLUSION

Our study provided a novel mechanism of DMY boosted chemosensitivity in human CRC. The downstream signals of DMY, NF-κB or Nrf2 could also be potential targets for the treatment of CRC.

Next generation sequencing reveals co-existence of hereditary spherocytosis and Dubin–Johnson syndrome in a Chinese gril: A case report

BACKGROUND

Hereditary spherocytosis (HS) is a hereditary disease of hemolytic anemia that occurs due to the erythrocyte membrane defects. Dubin–Johnson syndrome (DJS), which commonly results in jaundice, is a benign hereditary disorder of bilirubin clearance that occurs only rarely. The co-occurrence of HS and DJS is extremely rare. We recently diagnosed and treated a case of co-occurring HS and DJS.

CASE SUMMARY

A 21-year-old female patient presented to our department because of severe jaundice, severe splenomegaly, and mild anemia since birth. We eventually confirmed the diagnosis of co-occurring DJS and HS by next generation sequencing (NGS). The treatment of ursodeoxycholic acid in combination with phenobarbital successfully increased hemoglobin and reduced total bilirubin and direct bilirubin.

CONCLUSION

The routine application of NGS can efficiently render a definite diagnosis when inherited disorders are suspected.

Gender-Specific Association Between ABCC2 -24C>T SNP and Reduction in Triglycerides in Chilean Patients Treated With Atorvastatin

Statins are the first-line therapy prescribed to lower plasma cholesterol levels. Although being safe and showing several beneficial cholesterol-independent pleiotropic effects, a significant variability regarding statin's therapeutic goals has been abundantly documented, but less understood. We aimed to investigate the influence of the ABCC2 -24C>T single nucleotide polymorphism on Chilean hypercholesterolaemic individuals treated for 4 weeks with 10 mg/day atorvastatin. A total of 127 individuals medicated with atorvastatin 10 mg/day/4 weeks were included. Lipid profiles were determined before and after drug administration by conventional assays. Genotyping of the ABCC2 rs717620 SNP (-24C>T) was performed with TaqMan^® Drug Metabolism Genotyping Assays. As expected, atorvastatin reduced TC, LDL-C and TG concentrations (p < 0.05). Also, HDL-C levels were increased (p < 0.05). Minor allele frequency for the rs717620 was 0.232. Overall, atorvastatin response was not associated with the ABCC2 rs717620 SNP (p > 0.05). Nonetheless, in male individuals carrying the -24T allele, we observed an attenuated reduction in both TG values and the TG/HDL-C ratio after 10 mg/day atorvastatin. This study indicates that TG levels and the TG/HDL-C ratio are affected by the rs717620 SNP in Chilean males but not female individuals after atorvastatin treatment.

Identification of a compound heterozygous mutation of ABCC2 in a patient with hyperbilirubinemia

Bilirubin is the end product of heme catabolism, which is produced primarily from the breakdown of erythrocyte hemoglobin in the reticuloendothelial system. Hyperbilirubinemia is induced not only by increased bilirubin synthesis, but can also be caused by decreased bilirubin clearance. There are several disorders, which can contribute to hyperbilirubinemia, including Dubin‑Johnson syndrome (DJS). DJS is a rare autosomal recessive disorder, which is characterized by predominantly conjugated hyperbilirubinemia without progression to end‑stage liver disease. Previous studies have demonstrated that defects in multidrug resistance proteins ATP‑binding cassette C2 (ABCC2)/multidrug resistance‑associated protein 2 (MRP2) contribute to DJS. In the present study, a case of a patient with hyperbilirubinemia was examined and identified a compound heterozygous mutation in the ABCC2 gene (p.T435P and W442X). These were predicted to be deleterious by three bioinformatics programs (Polymorphism Phenotyping‑2, Sorting Intolerant From Tolerant and MutationTaster). These finding expand on the spectrum of ABCC2 mutations and provide additional evidence that ABCC2 is key in the development of DJS.

肝脏转运体表达和功能的变化对肝疾病的影响

转运体是药物吸收、分布、代谢和排泄的重要决定因素, 在肝脏表达尤为广泛. 肝脏转运体可以摄取大多数内源性物质、营养物质和外源性物质进入肝脏, 在肝脏内经过一系列的代谢转化, 最终将其外排入胆汁, 并由胆汁排到肝外. 越来越多的证据表明, 肝脏疾病状态下转运体的表达和功能会发生改变, 影响药物在体内的处置过程, 进而增加药物相互作用的可能性, 同时加大了疾病药物治疗的难度. 本文从肝脏摄取型和外排型转运体两方面出发, 针对肝脏转运体表达和功能的变化对肝疾病的影响作一综述.