MicroRNAs (miRNAs) are attractive therapeutic targets and promising candidates as molecular biomarkers for various therapy-resistant tumors. However, the association between miRNAs and drug resistance in melanoma remains to be elucidated. We used an integrative genomic analysis to comprehensively study the miRNA expression profiles of drug-resistant melanoma patients and cell lines. MicroRNA-181a and -181b (miR181a/b) were identified as the most significantly down-regulated miRNAs in resistant melanoma patients and cell lines. Re-establishment of miR-181a/b expression reverses the resistance of melanoma cells to the BRAF inhibitor dabrafenib. Introduction of miR-181 mimics markedly decreases the expression of TFAM in A375 melanoma cells resistant to BRAF inhibitors. Furthermore, melanoma growth was inhibited in A375 and M14 resistant melanoma cells transfected with miR-181a/b mimics, while miR-181a/b depletion enhanced resistance in sensitive cell lines. Collectively, our study demonstrated that miR-181a/b could reverse the resistance to BRAF inhibitors in dabrafenib resistant melanoma cell lines. In addition, miR-181a and -181b are strongly down-regulated in tumor samples from patients before and after the development of resistance to targeted therapies. Finally, melanoma tissues with high miR-181a and -181b expression presented favorable outcomes in terms of Progression Free Survival, suggesting that miR-181 is a clinically relevant candidate for therapeutic development or biomarker-based therapy selection.

Renal ultrasound scan, circulating creatinine and calcium, and the urinary calcium excretion rate were investigated in 57 patients with clinically and genetically typical Williams-Beuren syndrome (25 female and 32 male subjects, aged from 1.0 year to 23 years, median 8.5 years) on regular follow up at our institution. Twenty-three unilateral abnormalities were detected in 20 patients: pelvic dilatation ( n=6), renal hypoplasia ( n=5), isolated renal cyst ( n=3), kidney surface irregularity ( n=3), kidney duplication ( n=2), renal agenesis ( n=1), megaureter ( n=1), pelvic kidney dystopia ( n=1), and renal stone ( n=1). Both infantile hypercalcemia and nephrocalcinosis was absent in the 57 patients. Mild hypercalcemia was noted in 1 and mild hypercalciuria in 2 patients after the 1st year of life. In conclusion, the study indicates the frequent occurrence of intrinsic renal tract abnormalities detected by ultrasonography in Williams-Beuren syndrome. However, the study does not confirm the importance given in the past to the occurrence of hypercalcemia and hypercalciuria.

α1-Antitrypsin (AAT) deficiency is a common genetic disease presenting with lung and liver diseases. AAT deficiency results from pathogenic variants in the SERPINA1 gene encoding AAT and the common mutant Z allele of SERPINA1 encodes for Z α1-antitrypsin (ATZ), a protein forming hepatotoxic polymers retained in the endoplasmic reticulum of hepatocytes. PiZ mice express the human ATZ and are a valuable model to investigate the human liver disease of AAT deficiency. In this study, we investigated differential expression of microRNAs (miRNAs) between PiZ and control mice and found that miR-34b/c was up-regulated and its levels correlated with intrahepatic ATZ. Furthermore, in PiZ mouse livers, we found that Forkhead Box O3 (FOXO3) driving microRNA-34b/c (miR‐34b/c) expression was activated and miR-34b/c expression was dependent upon c-Jun N-terminal kinase (JNK) phosphorylation on Ser574. Deletion of miR-34b/c in PiZ mice resulted in early development of liver fibrosis and increased signaling of platelet-derived growth factor (PDGF), a target of miR-34b/c. Activation of FOXO3 and increased miR-34c were confirmed in livers of humans with AAT deficiency. In addition, JNK-activated FOXO3 and miR-34b/c up-regulation were detected in several mouse models of liver fibrosis. This study reveals a pathway involved in liver fibrosis and potentially implicated in both genetic and acquired causes of hepatic fibrosis.

a 1 -Antitrypsin (AAT) deficiency is one of the most common genetic disorders and the liver disease due to the Z mutant of AAT (ATZ) is a prototype of conformational disorder due to protein misfolding with consequent aberrant intermolecular protein aggregation. In the present study, we found that livers of PiZ transgenic mice expressing human ATZ have altered expression of a network of hepatocyte transcriptional factors, including hepatocyte nuclear factor-4a, that is early down-regulated and induces a transcriptional repression of ATZ expression. Reduced hepatocyte nuclear factor-4a was associated with activation of b-catenin, which regulates liver zonation. Livers of PiZ mice and human patients with AAT deficiency were both found to have a severe perturbation of liver zonation. Functionally, PiZ mice showed a severe defect of ureagenesis, as shown by increased baseline ammonia, and reduced urea production and survival after an ammonia challenge. Down-regulation of hepatocyte nuclear factor-4a expression and defective zonation in livers have not been recognized so far as features of the liver disease caused by ATZ and are likely involved in metabolic disturbances and in the increased risk of hepatocellular carcinoma in patients with AAT deficiency. Conclusion: The findings of this study are consistent with the concept that abnormal AAT protein conformation and intrahepatic accumulation have broad effects on metabolic liver functions. (HEPATOLOGY 2017;66:124-135) a 1 -Antitrypsin (AAT) deficiency (AATD) is one of the most common genetic disorders. The Z deficiency allele (p.Glu342Lys) of the SERPINA1 gene is present in 1 in 25 of the north European Caucasian population, of whom 1 in 2,000 to 1 in 3,500 are homozygotes.(1) The Z mutation results in deficiency of the major circulating protease inhibitor AAT predisposing to early-onset panlobular basal emphysema. Concomitantly, it causes retention of the protein within hepatocytes that is associated with neonatal hepatitis, cirrhosis, and hepatocellular carcinoma (HCC).(1,2) The natural history of liver disease due to homozygous Z allele is highly variable, and approximately 20% of homozygous ZZ newborns develop symptomatic cholestatic hepatitis.(3) Approximately 50% of ZZ infants and children are likely to develop Abbreviations: AAT, a 1 -antitrypsin; AATD, AAT deficiency; ARG1, arginase 1; ATZ, AAT encoded by the Z allele; CDH1, cadherin-1;

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