Full-length ATP7B reconstituted through protein trans-splicing corrects Wilson disease in mice.

Wilson disease (WD) is a genetic disorder of copper homeostasis, caused by deficiency of the copper transporter ATP7B. Gene therapy with recombinant adeno-associated vectors (AAV) holds promises for WD treatment. However, the full-length human ATP7B gene exceeds the limited AAV cargo capacity, hampering the applicability of AAV in this disease context. To overcome this limitation, we designed a dual AAV vector approach using split intein technology. Split inteins catalyze seamless ligation of two separate polypeptides in a highly specific manner. We selected a DnaE intein from Nostoc punctiforme (Npu) that recognizes a specific tripeptide in the human ATP7B coding sequence. We generated two AAVs expressing either the 5'-half of a codon-optimized human ATP7B cDNA followed by the N-terminal Npu DnaE intein or the C-terminal Npu DnaE intein followed by the 3'-half of ATP7B cDNA, under the control of a liver-specific promoter. Intravenous co-injection of the two vectors in wild-type and Atp7b -/- mice resulted in efficient reconstitution of full-length ATP7B protein in the liver. Moreover, Atp7b -/- mice treated with intein-ATP7B vectors were protected from liver damage and showed improvements in copper homeostasis. Taken together, these data demonstrate the efficacy of split intein technology to drive the reconstitution of full-length human ATP7B and to rescue copper-mediated liver damage in Atp7b -/- mice, paving the way to the development of a new gene therapy approach for WD.

The phosphatase Shp1 interacts with and dephosphorylates cortactin to inhibit invadopodia function.

BACKGROUND: Invadopodia are actin-based cell-membrane protrusions associated with the extracellular matrix degradation accompanying cancer invasion. The elucidation of the molecular mechanisms leading to invadopodia formation and activity is central for the prevention of tumor spreading and growth. Protein tyrosine kinases such as Src are known to regulate invadopodia assembly, little is however known on the role of protein tyrosine phosphatases in this process. Among these enzymes, we have selected the tyrosine phosphatase Shp1 to investigate its potential role in invadopodia assembly, due to its involvement in cancer development. METHODS: Co-immunoprecipitation and immunofluorescence studies were employed to identify novel substrate/s of Shp1AQ controlling invadopodia activity. The phosphorylation level of cortactin, the Shp1 substrate identified in this study, was assessed by immunoprecipitation, in vitro phosphatase and western blot assays. Short interference RNA and a catalytically-dead mutant of Shp1 expressed in A375MM melanoma cells were used to evaluate the role of the specific Shp1-mediated dephosphorylation of cortactin. The anti-invasive proprieties of glycerophosphoinositol, that directly binds and regulates Shp1, were investigated by extracellular matrix degradation assays and in vivo mouse model of metastasis. RESULTS: The data show that Shp1 was recruited to invadopodia and promoted the dephosphorylation of cortactin at tyrosine 421, leading to an attenuated capacity of melanoma cancer cells to degrade the extracellular matrix. Controls included the use of short interference RNA and catalytically-dead mutant that prevented the dephosphorylation of cortactin and hence the decrease the extracellular matrix degradation by melanoma cells. In addition, the phosphoinositide metabolite glycerophosphoinositol facilitated the localization of Shp1 at invadopodia hence promoting cortactin dephosphorylation. This impaired invadopodia function and tumor dissemination both in vitro and in an in vivo model of melanomas. CONCLUSION: The main finding here reported is that cortactin is a specific substrate of the tyrosine phosphatase Shp1 and that its phosphorylation/dephosphorylation affects invadopodia formation and, as a consequence, the ability of melanoma cells to invade the extracellular matrix. Shp1 can thus be considered as a regulator of melanoma cell invasiveness and a potential target for antimetastatic drugs. Video abstract.

Up-regulation of miR-34b/c by JNK and FOXO3 protects from liver fibrosis.

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.

Coordinate Modulation of Glycolytic Enzymes and OXPHOS by Imatinib in BCR-ABL Driven Chronic Myelogenous Leukemia Cells.

Since many oncogenes, including BCR-ABL, may promote the acquisition and maintenance of the glycolytic phenotype, we tested whether treatment of BCR-ABL-driven human leukemia cells with imatinib, a selective BCR-ABL inhibitor, can modulate the expression of key glycolytic enzymes and mitochondrial complex subunits thus causing alterations of glucose metabolism. BCR-ABL-driven K562 and KCL-22 cells were incubated with increasing concentrations of imatinib to preliminarily test drug sensitivity. Then untreated and treated cells were analyzed for levels of BCR-ABL signaling mediators and key proteins of glycolytic cascade and oxidative phosphorylation. Effective inhibition of BCR-ABL caused a concomitant reduction of p-ERK1/2, p-AKT, phosphorylated form of STAT3 (at Tyr705 and Ser727), c-Myc and cyclin D1 along with an increase of cleaved PARP and caspase 3 at 48 h after treatment. Furthermore, a strong reduction of the hexokinase II (HKII), phosphorylated form of PKM2 (at Tyr105 and Ser37) and lactate dehydrogenase A (LDH-A) was observed in response to imatinib along with a strong upregulation of mitochondrial complexes (OXPHOS). According to these findings, a significant reduction of glucose consumption and lactate secretion along with an increase of intracellular ATP levels was observed in response to imatinib. Our findings indicate that imatinib treatment of BCR-ABL-driven human leukemia cells reactivates mitochondrial oxidative phosphorylation thus allowing potential co-targeting of BCR-ABL and OXPHOS.

Neutrophil Extracellular Traps as an Adhesion Substrate for Different Tumor Cells Expressing RGD-Binding Integrins.

Neutrophil extracellular traps (NETs), in addition to their function as a host defense mechanism, play a relevant role in thrombus formation and metastatic dissemination of cancer cells. Here we screened different cancer cell lines endogenously expressing a variety of integrins for their ability to bind to NETs. To this end, we used NETs isolated from neutrophil-like cells as a substrate for adhesion assays of HT1080, U-87 MG, H1975, DU 145, PC-3 and A-431 cells. Levels of α5, αIIb, αv, ß1, ß3 and ß5 chains were determined by western blot analysis in all cell lines and levels of whole integrins on the plasma membrane were assessed by fluorescence-activated cell sorting (FACS) analysis. We found that high levels of α5ß1, αvß3 and αvß5 enhance cell adhesion to NETs, whereas low expression of α5ß1 prevents cell attachment to NETs. Excess of cyclic RGD peptide inhibited cell adhesion to NETs by competing with fibronectin within NETs. The maximal reduction of such adhesion was similar to that obtained by DNase 1 treatment causing DNA degradation. Our findings indicate that NETs from neutrophil-like cells may be used as a substrate for large screening of the adhesion properties of cancer cells expressing a variety of RGD-binding integrins.

Inositol Trisphosphate Receptor Type 3-mediated Enhancement of EGFR and MET Cotargeting Efficacy in Non-Small Cell Lung Cancer Detected by 18F-fluorothymidine.

Purpose: Our aim was to test whether imaging with 18F-fluorothymidine (18F-FLT) PET/CT was able to detect the combined effects of EGFR and MET inhibitors in oncogene-driven non-small cell lung cancer (NSCLC) and to elucidate the mechanisms underlying the enhanced efficacy of drug combination.Experimental Design: NSCLC cells bearing MET amplification (H1993 and H820) were treated with EGFR and MET inhibitors either alone or in combination and then tested for cell viability and inhibition of signaling. Nude mice bearing H1993 tumors underwent 18F-FLT PET/CT scan before and after treatment with erlotinib and crizotinib alone or in combination (1:1 ratio) and posttreatment changes of 18F-FLT uptake in tumors were determined. The role of inositol trisphosphate receptor type 3 (IP3R3) in mediating the combined action of EGFR and MET inhibitors was tested by transfecting NSCLC cells with IP3R3-targeted siRNA.Results: Imaging studies showed a significant reduction of 18F-FLT uptake in response to combined treatment with EGFR and MET inhibitors that was higher than that obtained with single agents (ANOVA, F-ratio = 6.215, P = 0.001). Imaging findings were confirmed by analysis of surgically excised tumors. Levels of IP3R3 were significantly reduced in both cells and tumors after treatment with crizotinib, whereas EGFR inhibitors caused a reduction of IP3R3 interaction with K-Ras mainly through dephosphorylation of serine residues of K-Ras.Conclusions: Our findings indicate that 18F-FLT PET/CT is able to detect the enhanced efficacy of EGFR and MET inhibitors in oncogene-driven NSCLC and that such enhancement is mediated by IP3R3 through its interaction with K-Ras. Clin Cancer Res; 24(13); 3126-36. ©2018 AACR.

Integrin-dependent cell adhesion to neutrophil extracellular traps through engagement of fibronectin in neutrophil-like cells.

Neutrophil extracellular traps (NETs), originally recognized as a host defense mechanism, were reported to promote thrombosis and metastatic dissemination of cancer cells. Here we tested the role of integrins α5ß1 and ανß3 in the adhesion of cancer cells to NETs. Neutrophil-like cells stimulated with calcium ionophore (A23187) were used as a stable source of cell-free NETs-enriched suspensions. Using NETs as an adhesion substrate, two human K562 cell lines, differentially expressing α5ß1 and ανß3 integrins, were subjected to adhesion assays in the presence or absence of DNAse 1, blocking antibodies against α5ß1 or ανß3, alone or in combination with DNAse 1, and Proteinase K. As expected DNAse 1 treatment strongly inhibited adhesion of both cell lines to NETs. An equivalent significant reduction of cell adhesion to NETs was obtained after treatment of cells with blocking antibodies against α5ß1 or ανß3 indicating that both integrins were able to mediate cell adhesion to NETs. Furthermore, the combination of DNAse 1 and anti-integrin antibody treatment almost completely blocked cell adhesion. Western blot analysis and immunoprecipitation experiments showed a dose-dependent increase of fibronectin levels in samples from stimulated neutrophil-like cells and a direct or indirect interaction of fibronectin with histone H3. Finally, co-immunolocalization studies with confocal microscopy showed that fibronectin and citrullinated histone H3 co-localize inside the web-structure of NETs. In conclusion, our study showed that α5ß1 and ανß3 integrins mediate cell adhesion to NETs by binding to their common substrate fibronectin. Therefore, in addition to mechanical trapping and aspecific adsorption of different cell types driven by DNA/histone complexes, NETs may provide specific binding sites for integrin-mediated cell adhesion of neutrophils, platelets, endothelial and cancer cells thus promoting intimate interactions among these cells.

Early 18F-FDG uptake as a reliable imaging biomarker of T790M-mediated resistance but not MET amplification in non-small cell lung cancer treated with EGFR tyrosine kinase inhibitors.

BACKGROUND: The two main mechanisms of resistance to EGFR tyrosine kinase inhibitors (TKIs) in non-small cell lung cancer (NSCLC) are the occurrence of T790M secondary mutation in the kinase domain of EGFR and MET amplification. The aim of the present study was to test whether early changes of 18F-fluorodeoxyglucose (18F-FDG) uptake in animal models bearing erlotinib-resistant NSCLC may have different imaging patterns of response to erlotinib depending on the molecular mechanisms underlying resistance. Animal tumor models were developed using NSCLC H1975 cells bearing the T790M mutation and H1993 cells with MET amplification. Nude mice bearing erlotinib-resistant H1975 and H1993 xenografts (four animals for each cell line and for each treatment) were subjected to 18F-FDG PET/CT scan before and immediately after treatment (50 mg/kg p.o. for 3 days) with erlotinib, WZ4002, crizotinib, or vehicle. A three-dimensional region of interest analysis was performed to determine the percent change of 18F-FDG uptake in response to treatment. At the end of the imaging studies, tumors were removed and analyzed for glycolytic and mitochondrial proteins as well as levels of cyclin D1. RESULTS: Imaging studies with 18F-FDG PET/CT in H1975 tumor-bearing mice showed a reduction of 18F-FDG uptake of 25.87 % ± 8.93 % after treatment with WZ4002 whereas an increase of 18F-FDG uptake up to 23.51 % ± 9.72 % was observed after treatment with erlotinib or vehicle. Conversely, H1993 tumors showed a reduction of 18F-FDG uptake after treatment with both crizotinib (14.70 % ± 1.30 %) and erlotinib (18.40 % ± 9.19 %) and an increase of tracer uptake in vehicle-treated (56.65 % ± 5.65 %) animals. The in vivo reduction of 18F-FDG uptake was always associated with downregulation of HKII and p-PKM2 Tyr105 glycolytic proteins and upregulation of mitochondrial complexes (subunits I-IV) in excised tumors. CONCLUSIONS: 18F-FDG uptake is a reliable imaging biomarker of T790M-mediated resistance and its reversal in NSCLC whereas it may not be accurate in the detection of MET-mediated resistance.

Reversal of Warburg Effect and Reactivation of Oxidative Phosphorylation by Differential Inhibition of EGFR Signaling Pathways in Non-Small Cell Lung Cancer.

PURPOSE: One of the hallmarks of cancer cells is the excessive conversion of glucose to lactate under normoxic conditions, also known as the Warburg effect. Here, we tested whether the targeted inhibition of EGFR may revert this effect and reactivate mitochondrial oxidative phosphorylation in non-small cell lung cancer (NSCLC). EXPERIMENTAL DESIGN: Sensitive (HCC827) and resistant (H1975 and H1993) NSCLC cells were treated with a panel of EGFR or MET inhibitors, and then tested for changes of EGFR signaling, glycolytic cascade, and mitochondrial function. Silencing of key glycolytic enzymes was then performed with targeted siRNAs. Furthermore, tumor-bearing nude mice treated with EGFR inhibitors were evaluated with (18)F-FDG PET/CT and tumors were analyzed for glycolytic and mitochondrial proteins. RESULTS: Effective inhibition of EGFR signaling in NSCLC cells induced a dramatic reduction of hexokinase II (HKII) and phospho-pyruvate kinase M2 (p-PKM2, Tyr105) levels as well as an upregulation of mitochondrial complexes subunits (OXPHOS). Accordingly, a decreased lactate secretion and increased intracellular ATP levels were also observed in response to EGFR inhibitors. Downregulation of HKII and PKM2 by targeted siRNA transfection did not cause upregulation of OXPHOS but enhanced the effects of EGFR TKIs. Conversely, selective inhibition of AKT and ERK1/2 caused OXPHOS upregulation and glycolysis inhibition, respectively. Similar findings were obtained in tumors from animals treated with appropriate EGFR inhibitors. CONCLUSIONS: Our findings indicate that EGFR inhibitors may reactivate oxidative phosphorylation of cancer cells and provide a mechanistic clue for the rational combination of agents targeting EGFR-dependent proliferation and glucose metabolism in cancer therapy.

Monitoring reversal of MET-mediated resistance to EGFR tyrosine kinase inhibitors in non-small cell lung cancer using 3'-deoxy-3'-[18F]-fluorothymidine positron emission tomography.

PURPOSE: MET amplification is one of the mechanisms underlying acquired resistance to EGFR tyrosine kinase inhibitors (TKI) in non-small cell lung cancer (NSCLC). Here, we tested whether 3'-deoxy-3'-[(18)F]-fluorothymidine ([(18)F]FLT) positron emission tomography/computerized tomography (PET/CT) can detect MET-mediated resistance to EGFR TKIs and monitor the effects of MET inhibitors in NSCLC. EXPERIMENTAL DESIGN: H1993 and H820 NSCLC cells with high and low levels of MET amplification, respectively, and HCC827-expressing MET, but without gene amplification, were tested for the effects of MET inhibitors on the EGFR pathway and proliferation both in vitro and in vivo. Nude mice bearing NSCLCs with and without MET amplification were subjected to [(18)F]FLT PET/CT before and after treatment with crizotinib or erlotinib (50 mg/kg and 100 mg/kg p.o. for 3 days). RESULTS: H1993 cells showed high responsiveness to MET inhibitors and were resistant to erlotinib. Conversely, HCC827 cells showed high sensitivity to erlotinib and were resistant to MET inhibitors. Accordingly, H1993 tumors bearing MET amplification showed a mean reduction in [(18)F]FLT uptake of 28% and 41% after low- and high-dose treatment with crizotinib for 3 days, whereas no posttherapy changes of [(18)F]FLT uptake were observed in HCC827 tumors lacking MET amplification. Furthermore, a persistently high [(18)F]FLT uptake was observed in H1993 tumors after treatment with erlotinib, whereas HCC827 tumors showed up to 39% reduction of [(18)F]FLT uptake following erlotinib treatment. Imaging findings were confirmed by Ki67 immunostaining of tumor sections. CONCLUSIONS: [(18)F]FLT PET/CT can detect MET-mediated resistance to EGFR TKIs and its reversal by MET inhibitors in NSCLC.

Isolation and characterization of multipotent cells from human fetal dermis.

We report that cells from human fetal dermis, termed here multipotent fetal dermal cells, can be isolated with high efficiency by using a nonenzymatic, cell outgrowth method. The resulting cell population was consistent with the definition of mesenchymal stromal cells by the International Society for Cellular Therapy. As multipotent fetal dermal cells proliferate extensively, with no loss of multilineage differentiation potential up to passage 25, they may be an ideal source for cell therapy to repair damaged tissues and organs. Multipotent fetal dermal cells were not recognized as targets by T lymphocytes in vitro, thus supporting their feasibility for allogenic transplantation. Moreover, the expansion protocol did not affect the normal phenotype and karyotype of cells. When compared with adult dermal cells, fetal cells displayed several advantages, including a greater cellular yield after isolation, the ability to proliferate longer, and the retention of differentiation potential. Interestingly, multipotent fetal dermal cells expressed the pluripotency marker SSEA4 (90.56 ± 3.15% fetal vs. 10.5 ± 8.5% adult) and coexpressed mesenchymal and epithelial markers (>80% CD90(+)/CK18(+) cells), coexpression lacking in the adult counterparts isolated under the same conditions. Multipotent fetal dermal cells were able to form capillary structures, as well as differentiate into a simple epithelium in vitro, indicating skin regeneration capabilities.

Early detection, prevention and management of cutaneous adverse events due to sorafenib: recommendations from the Sorafenib Working Group.

Cutaneous adverse events commonly reported with tyrosine kinase inhibitors (TKIs) in the treatment of malignancies, represent an important clinical concern since they can limit the optimal use of these novel drugs. Although there are numerous reports in the literature of these events there are no practical guidelines on how they should be managed. The Sorafenib Working Group (SWG) was established with the objective of developing recommendations to allow the early detection, prevention and management of cutaneous adverse events in everyday clinical practice. The SWG was a multidisciplinary team made up of experts in the field who were closely involved in the sorafenib clinical development program. This review provides an overview of the nature and incidence of cutaneous adverse events which manifest with sorafenib treatment and provides recommendations for their early detection and effective management in clinical practice.