Identification of RNF213 as a potential suppressor of local invasion in intrahepatic cholangiocarcinoma.

Intrahepatic cholangiocarcinoma (ICC) is a lethal cancer with poor survival especially when it spreads. The histopathology of its rare intraductal papillary neoplasm of the bile duct type (IPNB) characteristically shows cancer cells originating within the confined bile duct space. These cells eventually invade and infiltrate the nearby liver tissues, making it a good model to study the mechanism of local invasion, which is the earliest step of metastasis. To discover potential suppressor genes of local invasion in ICC, we analyzed the somatic mutation profiles and performed clonal evolution analyses of the 11 pairs of macrodissected IPNB tissues with local invasion (LI-IPNB) and IPNB tissues without local invasion from the same patients. We identified a protein-truncating variant (PTV) in an E3 ubiquitin ligase, RNF213 (c.6967C>T; p.Gln2323X; chr17: 78,319,102 [hg19], exon 29), as the most common PTV event in LI-IPNB samples (4/11 patients). Knockdown of RNF213 in HuCCT1 and YSCCC cells showed increased migration and invasion, and reduced vasculogenic mimicry, but maintained normal proliferation. Transcriptomic analysis of the RNF213-knockdown versus control cells was then performed in the HuCCT1, YSCCC, and KKU-100 cells. Gene Ontology (GO) enrichment analysis of the common differentially expressed genes revealed significantly altered cytokine and oxidoreductase-oxidizing metal ions activities, as confirmed by western blotting. Gene Set Enrichment Analysis (GSEA) identified the most enriched pathways being oxidative phosphorylation, fatty acid metabolism, reactive oxygen species, adipogenesis, and angiogenesis. In sum, loss of function of RNF213 is a common genetic alteration in LI-IPNB tissues. RNF213 knockdown leads to increased migration and invasion of ICC cells, potentially through malfunctions of the pathways related inflammation, and energy metabolisms.

Ceftriaxone exerts antitumor effects in MYCN-driven retinoblastoma and neuroblastoma by targeting DDX3X for translation repression.

MYCN proto-oncogene, bHLH transcription factor (MYCN) amplification is associated with aggressive retinoblastoma (RB) and neuroblastoma (NB) cancer recurrence that is resistant to chemotherapies. Therefore, there is an urgent need to identify new therapeutic tools. This study aimed to evaluate the potential repurposing of ceftriaxone for the treatment of MYCN-amplified RB and NB, based on the clinical observations that the drug was serendipitously found to decrease the volume of the MYCN-driven RB subtype. Using patient-derived tumor organoids and tumor cell lines, we demonstrated that ceftriaxone is a potent and selective growth inhibitor targeting MYCN-driven RB and NB cells. Profiling of drug-induced transcriptomic changes, cell-cycle progression, and apoptotic death indicated cell-cycle arrest and death of drug-treated MYCN-amplified tumor cells. Drug target identification, using an affinity-based proteomic and molecular docking approach, and functional studies of the target proteins revealed that ceftriaxone targeted DEAD-box helicase 3 X-linked (DDX3X), thereby inhibiting translation in MYCN-amplified tumors but not in MYCN-nonamplified cells. The data suggest the feasibility of repurposing ceftriaxone as an anticancer drug and provide insights into the mechanism of drug action, highlighting DDX3X as a potential target for treating MYCN-driven tumors.

Silencing of the Long Noncoding RNA MYCNOS1 Suppresses Activity of MYCN-Amplified Retinoblastoma Without RB1 Mutation.

Purpose: MYCNOS (MYCN opposite strand) is co-amplified with MYCN in pediatric cancers, including retinoblastoma. MYCNOS encodes several RNA variants whose functions have not been elucidated in retinoblastoma. Thus, we attempted to identify MYCNOS variants in retinoblastoma and aimed to decipher the role of MYCNOS variant 1 (MYCNOS1) on the activity of MYCN-amplified retinoblastoma. Methods: The profiles of MYCNOS variants and MYCN status were determined in 17 retinoblastoma tissues, cell lines, retinas, and retinal organoids. A functional study of MYCNOS1 expression was conducted in patient-derived tumor cells and in retinoblastoma cell lines via short hairpin RNA-mediated gene silencing. We carried out MYCN expression, cell viability, cell cycle, apoptosis, soft agar colony formation, and transwell assays to examine the role of MYCNOS1 in MYCN and cell behaviors. We analyzed a transcriptome of MYCN-amplified retinoblastoma cells deficient for MYCNOS1 and, finally, tested the responses of these cells to chemotherapeutic agents. Results: Expression of MYCNOS1 was associated with the expression and copy number of MYCN. Knockdown of MYCNOS1 caused instability of the MYCN protein, leading to cell cycle arrest and impaired proliferation and chemotaxis-directed migration in MYCN-amplified retinoblastoma cells in which RB1 was intact. MYCNOS1 expression was associated with gene signatures of photoreceptor cells and epithelial-mesenchymal transition. MYCNOS1 silencing enhanced the response of retinoblastoma cells to topotecan but not carboplatin. Conclusions: MYCNOS1 supports progression of retinoblastoma. Inhibition of MYCNOS1 expression may be necessary to suppress MYCN activity when treating MYCN-amplified cancers without RB1 mutation.

A three-dimensional organoid model recapitulates tumorigenic aspects and drug responses of advanced human retinoblastoma.

Persistent or recurrent retinoblastoma (RB) is associated with the presence of vitreous or/and subretinal seeds in advanced RB and represents a major cause of therapeutic failure. This necessitates the development of novel therapies and thus requires a model of advanced RB for testing candidate therapeutics. To this aim, we established and characterized a three-dimensional, self-organizing organoid model derived from chemotherapy-naïve tumors. The responses of organoids to drugs were determined and compared to relate organoid model to advanced RB, in terms of drug sensitivities. We found that organoids had histological features resembling retinal tumors and seeds and retained DNA copy-number alterations as well as gene and protein expression of the parental tissue. Cone signal circuitry (M/L+ cells) and glial tumor microenvironment (GFAP+ cells) were primarily present in organoids. Topotecan alone or the combined drug regimen of topotecan and melphalan effectively targeted proliferative tumor cones (RXRγ+ Ki67+) in organoids after 24-h drug exposure, blocking mitotic entry. In contrast, methotrexate showed the least efficacy against tumor cells. The drug responses of organoids were consistent with those of tumor cells in advanced disease. Patient-derived organoids enable the creation of a faithful model to use in examining novel therapeutics for RB.

Molecular Cloning, Structural Modeling and the Production of Soluble Triple-Mutated Diphtheria Toxoid (K51E/G52E/E148K) Co-expressed with Molecular Chaperones in Recombinant Escherichia coli.

CRM197 is a diphtheria toxin (DT) mutant (G52E) which has been used as a carrier protein for conjugate vaccines. However, it still possesses cytotoxicity toward mammalian cells. The goal of this project was to produce a non-toxic and soluble CRM197EK through introduction of triple amino acid substitutions (K51E/G52E/E148K) in Escherichia coli. The expression of CRM197EKTrxHis was optimized and co-expressed with different molecular chaperones. The soluble CRM197EKTrxHis was produced at a high concentration (97.33 ± 17.47 µg/ml) under the optimal condition (induction with 0.1 mM IPTG at 20 °C for 24 h). Cells containing pG-Tf2, expressing trigger factor and GroEL-GroES, accumulated the highest amount of soluble CRM197EKTrxHis at 111.24 ± 10.40 µg/ml after induction for 24 h at 20 °C. The soluble CRM197EKTrxHis still possesses nuclease activity and completely digest λDNA at 25 and 37 °C with 8- and 4-h incubation, respectively. Molecular modeling of diphtheria toxin, CRM197 and CRM197EK indicated that substitutions of two amino acids (K51E/E148K) may cause poor NAD binding, consistent with the lack of toxicity. Therefore, CRM197EK might be used as a new potential carrier protein. However, further in vivo study is required to confirm its roles as functional carrier protein in conjugate vaccines.

Flufenamic acid protects against intestinal fluid secretion and barrier leakage in a mouse model of Vibrio cholerae infection through NF-κB inhibition and AMPK activation.

Nuclear factor kappa B (NF-κB)-mediated inflammatory responses play crucial roles in the pathogenesis of diarrhea caused by the Vibrio cholerae El Tor variant (EL), which is a major bacterial strain causing recent cholera outbreaks. Flufenamic acid (FFA) has previously been demonstrated to be a potent activator of AMP-activated protein kinase (AMPK), which is a negative regulator of NF-κB signaling. This study aimed to investigate the anti-diarrheal efficacy of FFA in a mouse model of EL infection and to investigate the mechanisms by which FFA activates AMPK in intestinal epithelial cells (IEC). In a mouse closed loop model of EL infection, FFA treatment (20mg/kg) significantly abrogated EL-induced intestinal fluid secretion and barrier disruption. In addition, FFA suppressed NF-κB nuclear translocation and expression of proinflammatory mediators and promoted AMPK phosphorylation in the EL-infected mouse intestine. In T84 cells, FFA induced AMPK activation. Furthermore, FFA promoted tight junction assembly and prevented interferon gamma (IFN-γ)-induced barrier disruption in an AMPK-dependent manner. Biochemical and molecular docking analyses indicated that FFA activates AMPK via a direct stimulation of calcium/calmodulin-dependent protein kinase kinase beta (CaMKKß) activity. Collectively, our data indicate that FFA represents a class of existing drugs that may be of potential utility in the treatment of cholera caused by EL infection via AMPK-mediated suppression of NF-κB signaling in IEC.

Angiotensin-converting enzyme inhibitory and antioxidant peptides from digestion of larvae and pupae of Asian weaver ant, Oecophylla smaragdina, Fabricius.

BACKGROUND: Mixed larvae and pupae of weaver ant (Oecophylla smaragdina) are widely used as an important food ingredient in regions of Thailand. They have high nutritional values and comprise 53% protein and 13% lipid. Peptides derived from food proteins have been shown to possess biological activities. RESULTS: Peptides derived from pepsin and trypsin digestion of these weaver ant larvae and pupae were purified based on angiotensin-converting enzyme (ACE) inhibitory and antioxidant activities, and their amino acid sequences were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). In silico docking of peptides with ACE successfully predicted the inhibitory peptides as confirmed by their chemical synthesis. Two peptides with sequences of FFGT and LSRVP showed IC50 values for ACE inhibition of 19.5 ± 1.7 and 52.7 ± 4.0 µmol L-1 , respectively. In addition, one potent antioxidant peptide with a sequence of CTKKHKPNC showed IC50 values of 48.2 ± 2.1 µmol L-1 for DPPH assay and 38.4 ± 0.2 µmol L-1 for ABTS assay, respectively. CONCLUSION: These results indicate that proteins from larvae and pupae of weaver ants are potential sources of peptides with anti-ACE and antioxidation bioactivities. © 2016 Society of Chemical Industry.