Iron overload in hereditary tyrosinemia type 1 induces liver injury through the Sp1/Tfr2/hepcidin axis.

BACKGROUND & AIMS: Iron is an essential metal for fundamental metabolic processes, but little is known regarding the involvement of iron in other nutritional disorders. In the present study, we investigated disordered iron metabolism in a murine model of hereditary tyrosinemia type I (HT1), a disease of the tyrosine degradation pathway. METHODS: We analysed the status of iron accumulation following NTBC withdrawal from Fah(-/-) mice, a murine model for HT1. Liver histology and serum parameters were used to assess the extent of liver injury and iron deposition. To determine the physiological significance of iron accumulation, mice were subjected to a low-iron food intake to reduce the iron accumulation. Mechanistic studies were performed on tissues and cells using immunoblotting, qRT-PCR, adenovirus transfection and other assays. RESULTS: Severe iron overload was observed in the murine model of HT1 with dramatically elevated hepatic and serum iron levels. Mechanistic studies revealed that downregulation and dysfunction of Tfr2 decreased hepcidin, leading to iron overload. The Fah(-/-) hepatocytes lost the ability of transferrin-sensitive induction of hepcidin. Forced expression of Tfr2 in the murine liver reduced the iron accumulation. Moreover, transcription factor Sp1 was downregulated and identified as a new regulator of Tfr2 here. Additionally, low-iron food intake effectively reduced the iron deposits, protected the liver and prolonged the survival in these mice. CONCLUSIONS: Iron was severely overloaded in the HT1 mice via the Sp1/Tfr2/Hepcidin axis. The iron overload induced liver injury in the HT1 mice, and reduction of the iron accumulation ameliorated liver injury. LAY SUMMARY: Primary and secondary iron overload is an abnormal status affecting millions of people worldwide. Here, we reported severe iron overload in a murine model of HT1, a disease of the tyrosine degradation pathway, and elucidated the mechanistic basis and the physiological significance of iron overload in HT1. These studies are of general interest not only with respect to secondary iron-induced liver injury in HT1 but also are important to elucidate the crosstalk between the two metabolic pathways.

hPCL3s Promotes Hepatocellular Carcinoma Metastasis by Activating ß-Catenin Signaling.

Two isoforms of human Polycomb-like protein 3 (hPCL3) have been reported as components of the nuclear Polycomb repressive complex 2 (PRC2), with the short isoform (hPCL3s) showing a dominant cytoplasmic localization. The function of cytoplasmic hPCL3s has, however, not been addressed. In this study, we report that hPCL3s is upregulated in clinical hepatocellular carcinoma (HCC) samples and its expression correlated with HCC clinical features. hPCL3s positively regulated the migration, invasion, and metastasis of HCC cells. hPCL3s interacted with components of the cytoplasmic ß-catenin destruction complex, inhibited ß-catenin degradation, and activated ß-catenin/T-cell factor signaling. Downstream of the ß-catenin cascade, IL6 mediated the motility-promoting functions of hPCL3s. Forced expression of hPCL3s in the liver of a HCC mouse model promoted tumorigenesis and metastasis. Taken together, these data show that hPCL3s promotes the metastasis of HCC by activating the ß-catenin/IL6 pathway.Significance: hPCL3s has an oncogenic role in hepatocellular carcinoma by activating the ß-catenin/IL6 signaling axis to promote metastasis. Cancer Res; 78(10); 2536-49. ©2018 AACR.

Cilia loss sensitizes cells to transformation by activating the mevalonate pathway.

Although cilia loss and cell transformation are frequently observed in the early stage of tumorigenesis, the roles of cilia in cell transformation are unknown. In this study, disrupted ciliogenesis was observed in cancer cells and pancreatic cancer tissues, which facilitated oncogene-induced transformation of normal pancreatic cells (HPDE6C7) and NIH3T3 cells through activating the mevalonate (MVA) pathway. Disruption of ciliogenesis up-regulated MVA enzymes through ß catenin-T cell factor (TCF) signaling, which synchronized with sterol regulatory element binding transcription factor 2 (SREBP2), and the regulation of MVA by ß-catenin-TCF signaling was recapitulated in a mouse model of pancreatic ductal adenocarcinoma (PDAC) and human PDAC samples. Moreover, disruption of ciliogenesis by depleting Tg737 dramatically promoted tumorigenesis in the PDAC mouse model, driven by KrasG12D , which was inhibited by statin, an inhibitor of the MVA pathway. Collectively, this study emphasizes the crucial roles of cilia in governing the early steps of the transformation by activating the MVA pathway, suggesting that statin has therapeutic potential for pancreatic cancer treatment.

Computed tomography manifestations of common inferior vena cava dysplasia and its clinical significance.

This study aimed to review and analyse the computed tomography (CT) imaging results of frequently encountered developmental anomalies of the inferior vena cava (IVC). The underlying clinical significance was evaluated with reference to the relevant literature. CT images of patients who received abdominal or thoracic scanning between July 2009 and September 2011 were reviewed. Developmental anomalies observed in the IVC were identified and categorised. Images of the cases with typical anomalies were presented and their developmental mechanism, as well as clinical significance, was discussed. The most frequently encountered IVC developmental anomalies include the left vena cava, double vena cava, azygos continuation of the IVC, left circumaortic renal vein, left retroaortic renal vein and retrocaval ureter. The embryogenesis of the IVC is a complex process that results in various congenital anomalies. The developmental anomalies of the IVC are distinguished using a CT scan and have significant implications on clinical perspective.

Determination of 2-hydroxyflutamide in human plasma by liquid chromatography-tandem mass spectrometry (LC-MS/MS): application to a bioequivalence study on Chinese volunteers.

A sensitive, simple and rapid ultra fast liquid chromatography (UFLC)-ESI-MS/MS method was developed for the determination of 2-hydroxyflutamide in human plasma using tegafur as the internal standard. The plasma sample was pretreated with methanol for protein precipitation and the analytes were separated on an Ultimate C18 column (5 microm, 2.1 mm x 50 mm, MD, USA) with the mobile phase consisted of acetonitrile and water (2:1, v/v). Detection was performed on a triple-quadrupole tandem mass spectrometer under a negative multiple reaction-monitoring mode (MRM). The mass transition ion-pair was followed as m/z 290.90-204.8 for 2-hydroxyflutamide and 198.9-128.8 for tegafur. Linear calibration curves were obtained in the concentration range of 1.742-1452 ng/ml with a lower limit of quantification of 1.742 ng/ml. The intra- and inter-batch precision values were less than 8.1% and 5.6%, respectively. The established method was successfully applied to a bioequivalence study of two flutamide preparations (250 mg) in 20 healthy male volunteers.

Determination of cefazedone in human plasma by high performance liquid chromatography-tandem mass spectrometry: Application to a pharmacokinetic study on Chinese volunteers.

A rapid, sensitive and simple high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed for determination of cefazedone in human plasma using metronidazole as internal standard (IS). The chromatographic separation was achieved on an Ultimate XB-CN column (2.1mm×150mm, 5µm) with an isocratic mobile phase of acetonitrile and 20mM ammonium acetate in 0.1% formic acid in water (15:85, v/v). Detection was performed using electrospray ionization in positive ion multiple reaction-monitoring mode (SRM), monitoring the transitions m/z 548.2→344.1 for cefazedone and m/z 172.2→128.1 for IS. Calibration curves were linear over a wide range of 0.20-401.12µg/mL for cefazedone in plasma. The lower limit of quantification (LLOQ) was 0.20µg/mL. The intra- and inter-day precisions were less than 7.2%. The average recovery of cefazedone was 90.8-91.0%. The validated method was successfully applied to the pharmacokinetic study of cefazedone in Chinese healthy volunteers following intravenous (IV) administration of 500, 1000 and 2000mg cefazedone injection.

[Bioequivalence of tiopronin enteric capsules in healthy volunteers].

OBJECTIVE: To evaluate the bioequivalence of tiopronin enteric capsules (testing preparation, T) versus tablets (reference preparation, R). METHODS: A single oral dose of tiopronin enteric capsules or tablets at 200 mg was administered in 2 groups of Chinese healthy volunteers (n=9) in a randomized crossover design at the interval of 2 weeks. The plasma concentrations of tiopronin were measured by HPLC-MS/MS, and the pharmacokinetic parameters were calculated by DAS 2.0 program. The bioequivalence between the two preparations was evaluated. RESULTS: The main pharmacokinetic parameters were as follows: C(max)(microg.ml(-1)) 3.612-/+1.2393 (R), 3.644-/+1.540 (T); t(max) 4.333-/+1.0853 (R), 3.611-/+1.420 (T); t((1/2))(h) 18.245-/+11.270 (R), 23.403-/+10.500 (T); AUC0-t (microg.h.ml(-1)) 18.732-/+6.92318 (R), 18.713-/+6.585 (T); AUC0-infinity (microg.h.ml(-1)) 21.900-/+7.31220 (R), 20.780-/+7.965 (T). The relative bioavailability of tiopronin enteric capsule was 103.712-/+23.956%, with 90% confidential intervals of ln(AUC0-->72), ln(AUC0-infinity) and ln(C(max)) of 91.1%-111.8%, 96.8%-118.3%, and 85.1%-113.0%, respectively. CONCLUSION: The tiopronin enteric capsules were bioequivalent to the tablets.