Application of molecular cytogenetic techniques to clarify apparently balanced complex chromosomal rearrangements in two patients with an abnormal phenotype: case report

<p>Abstract</p> <p>Background</p> <p>Complex chromosomal rearrangements (CCR) are rare cytogenetic findings that are difficult to karyotype by conventional cytogenetic analysis partially because of the relative low resolution of this technique. High resolution genotyping is necessary in order to identify cryptic imbalances, for instance near the multiple breakpoints, to explain the abnormal phenotype in these patients. We applied several molecular techniques to elucidate the complexity of the CCRs of two adult patients with abnormal phenotypes.</p> <p>Results</p> <p>Multicolour fluorescence in situ hybridization (M-FISH) showed that in patient 1 the chromosomes 1, 10, 15 and 18 were involved in the rearrangement whereas for patient 2 the chromosomes 5, 9, 11 and 13 were involved. A 250 k Nsp1 SNP-array analysis uncovered a deletion in chromosome region 10p13 for patient 1, harbouring 17 genes, while patient 2 showed no pathogenic gains or losses. Additional FISH analysis with locus specific BAC-probes was performed, leading to the identification of cryptic interstitial structural rearrangements in both patients.</p> <p>Conclusion</p> <p>Application of M-FISH and SNP-array analysis to apparently balanced CCRs is useful to delineate the complex chromosomal rearrangement in detail. However, it does not always identify cryptic imbalances as an explanation for the abnormal phenotype in patients with a CCR.</p

Tissue distribution and induction of human multidrug resistant protein 3

The multidrug resistance protein (MRP) family consists of several members and, for some of these transporter proteins, distinct roles in multidrug resistance and normal tissue functions have been well established (MRP1 and MRP2) or are still under investigation (MRP3). MRP3 expression studies in human tissues have been largely restricted to the mRNA level. In this report we extended these studies and further explored MRP3 expression at the protein level. Western blot and immunohistochemistry with two MRP3-specific monoclonal antibodies, M3II-9 and M3II-21, showed MRP3 protein to be present in adrenal gland, and kidney and in tissues of the intestinal tract: colon, pancreas, gallbladder, and liver. In epithelia, MRP3 was found to be located at the basolateral sides of cell membranes. In normal liver, MRP3 was detected at lower levels than anticipated from the mRNA data and was found present mainly in the bile ducts. In livers from patients with various forms of cholestasis, MRP3 levels were frequently increased in the proliferative cholangiocytes, with sometimes additional staining of the basolateral membranes of the hepatocytes. This was especially evident in patients with type 3 progressive familial intrahepatic cholestasis. The present results support the view that MRP3 plays a role in the cholehepatic and enterohepatic circulation of bile and in protection within the biliary tree and tissues along the bile circulation route against toxic bile constituents. The possible functional roles for MRP3 in the adrenal gland and in the kidney remain as yet unknown. In a panel of 34 tumor samples of various histogenetic origins, distinct amounts of MRP3 were detected in a limited number of cases, including lung, ovarian, and pancreatic cancers. These findings may be of potential clinical relevance when considering the drug treatment regimens for these tumor type

MRP3, an organic anion transporter able to transport anti-cancer drugs

The human multidrug-resistance protein (MRP) gene family contains at least six members: MRP1, encoding the multidrug-resistance protein; MRP2 or cMOAT, encoding the canalicular multispecific organic anion transporter; and four homologs, called MRP3, MRP4, MRP5, and MRP6. In this report, we characterize MRP3, the closest homolog of MRP1. Cell lines were retrovirally transduced with MRP3 cDNA, and new monoclonal antibodies specific for MRP3 were generated. We show that MRP3 is an organic anion and multidrug transporter, like the GS-X pumps MRP1 and MRP2. In Madin–Darby canine kidney II cells, MRP3 routes to the basolateral membrane and mediates transport of the organic anion S-(2,4-dinitrophenyl-)glutathione toward the basolateral side of the monolayer. In ovarian carcinoma cells (2008), expression of MRP3 results in low-level resistance to the epipodophyllotoxins etoposide and teniposide. In short-term drug exposure experiments, MRP3 also confers high-level resistance to methotrexate. Neither 2008 cells nor Madin–Darby canine kidney II cells overexpressing MRP3 showed an increase in glutathione export or a decrease in the level of intracellular glutathione, in contrast to cells overexpressing MRP1 or MRP2. We discuss the possible function of MRP3 in (hepatic) physiology and its potential contribution to drug resistance of cancer cells

La prison du Pied-du-Courant

Background & Aims: We have specified the features of progressive familial intrahepatic cholestasis type 3 and investigated in 31 patients whether a defect of the multidrug resistance 3 gene (MDR3) underlies this phenotype. Methods: MDR3 sequencing liver MDR3 immunohistochemistry, and biliary phospholipid dosage were performed, Results: Liver histology showed a pattern of biliary cirrhosis with patency of the biliary tree. Age at presentation ranged from the neonatal period to early adulthood. Sequence analysis revealed 16 different mutations in 17 patients. Mutations were identified on both alleles in 12 patients and only on 1 allele in 5, Four mutations lead to a frame shift, 2 are nonsense, and 10 are missense, An additional missense mutation probably representing a polymorphism was found in 5 patients, MDR3 mutations were associated with abnormal MDRB canalicular staining and a low proportion of biliary phospholipids, Gallstones or episodes of cholestasis of pregnancy were found in patients or parents. Children with missense mutations had a less severe disease and more often a beneficial effect of ursodeoxycholic acid therapy. Conclusions: At least one third of the patients with a progressive familial intrahepatic cholestasis type 3 phenotype have a proven defect of MDR3, This gene defect should also be considered in adult liver diseases

Impact of hepatic encephalopathy on liver transplant waiting list mortality in regions with different transplantation rates.

Overt hepatic encephalopathy (OHE) negatively impacts the prognosis of liver transplant candidates. However, it is not taken into account in most prioritizing organ allocation systems. We aimed to assess the impact of OHE on waitlist mortality in 3 cohorts of cirrhotic patients awaiting liver transplantation, with differences in the composition of patient population, transplantation policy, and transplantation rates. These cohorts were derived from two centers in the Netherlands (reference and validation cohort, n = 246 and n = 205, respectively) and one in Spain (validation cohort, n = 253). Competing-risk regression analysis was applied to assess the association of OHE with 1-year waitlist mortality. OHE was found to be associated with mortality, independently of MELD score, other cirrhosis-related complications and hepatocellular carcinoma (HCC; sHR = 4.19, 95% CI = 1.9-9.5, P = 0.001). The addition of extra MELD points for OHE counteracted its negative impact on survival. These findings were confirmed in the Dutch validation cohort, whereas in the Spanish cohort, containing a significantly greater proportion of HCC and with higher transplantation rates, OHE was not associated with mortality. In conclusion, OHE is an independent risk factor for 1-year waitlist mortality and might be a prioritization rule for organ allocation. However, its impact seems to be attenuated in settings with significantly higher transplantation rates

Immune responses in DAA treated chronic hepatitis C patients with and without prior RG-101 dosing

With the introduction of DAA's, the majority of treated chronic hepatitis C patients (CHC) achieve a viral cure. The exact mechanisms by which the virus is cleared after successful therapy, is still unknown. The aim was to assess the role of the immune system and miRNA levels in acquiring a sustained virological response after DAA treatment in CHC patients with and without prior RG-101 (anti-miR-122) dosing.In this multicenter, investigator-initiated study, 29 patients with hepatitis C virus (HCV) genotype 1 (n = 11), 3 (n = 17), or 4 (n = 1) infection were treated with sofosbuvir and daclatasvir ± ribavirin. 18 patients were previously treated with RG-101. IP-10 levels were measured by ELISA. Ex vivo HCV-specific T cell responses were quantified in IFN-γ-ELISpot assays. Plasma levels of miR-122 were measured by qPCR.All patients had an SVR12. IP-10 levels rapidly declined during treatment, but were still elevated 24 weeks after treatment as compared to healthy controls (median 53.82 and 39.4 pg/mL, p = 0.02). Functional IFN-γ HCV-specific T cell responses did not change by week 12 of follow-up (77.5 versus 125 SFU/10(6) PBMC, p = 0.46). At follow-up week 12, there was no difference in plasma miR-122 levels between healthy controls and patients with and without prior RG-101 dosing.Our data shows that successful treatment of CHC patients with and without prior RG-101 dosing results in reduction of broad immune activation, and normalization of miR-122 levels (EudraCT: 2014-002808-25).EudraCT: 2014-002808-25

Safety, tolerability, and antiviral effect of RG-101 in patients with chronic hepatitis C: a phase 1B, double-blind, randomised controlled trial

Background miR-122 is an important host factor for hepatitis C virus (HCV) replication. The aim of this study was to assess the safety and tolerability, pharmacokinetics, and antiviral effect of a single dose of RG-101, a hepatocyte targeted N-acetylgalactosamine conjugated oligonucleotide that antagonises miR-122, in patients with chronic HCV infection with various genotypes. Methods In this randomised, double-blind, placebo-controlled, multicentre, phase 1B study, patients were randomly assigned to RG-101 or placebo (7: 1). We enrolled men and postmenopausal or hysterectomised women (aged 18-65 years) with chronic HCV genotype 1, 3, or 4 infection diagnosed at least 24 weeks before screening who were either treatment naive to or relapsed after interferon-alpha based therapy. Patients with co-infection (hepatitis B virus or HIV infection), evidence of decompensated liver disease, or a history of hepatocellular carcinoma were excluded. Randomisation was done by an independent, unblinded, statistician using the SAS procedure Proc Plan. The first cohort received one subcutaneous injection of 2 mg/kg RG-101 or placebo; the second cohort received one subcutaneous injection of 4 mg/kg or placebo. Patients were followed up for 8 weeks (all patients) and up to 76 weeks (patients with no viral rebound and excluding those who were randomised to the placebo group) after randomisation. The primary objective was safety and tolerability of RG-101. This trial was registered with EudraCT, number 2013-002978-49. Findings Between June 4, 2014, and Oct 27, 2014, we enrolled 32 patients with chronic HCV genotype 1 (n=16), 3 (n=10), or 4 (n=6) infections. In the first cohort, 14 patients were randomly assigned to receive 2 mg/kg RG-101 and two patients were randomly assigned to receive placebo, and in the second cohort, 14 patients were randomly assigned to receive 4 mg/kg RG-101 and two patients were randomly assigned to receive placebo. Overall, 26 of the 28 patients dosed with RG-101 reported at least one treatment-related adverse event. At week 4, the median viral load reduction from baseline was 4.42 (IQR 3.23-5.00) and 5.07 (4.19-5.35) log(10) IU/mL in patients dosed with 2 mg/kg RG-101 or 4 mg/kg RG-101. Three patients had undetectable HCV RNA levels 76 weeks after a single dose of RG-101. Viral rebound at or before week 12 was associated with the appearance of resistance associated substitutions in miR-122 binding regions in the 5' UTR of the HCV genome. Interpretation This study showed that one administration of 2 mg/kg or 4 mg/kg RG-101, a hepatocyte targeted N-acetylgalactosamine conjugated anti-miR-122 oligonucleotide, was well tolerated and resulted in substantial viral load reduction in all treated patients within 4 weeks, and sustained virological response in three patients for 76 week