Gastrokine 1 mRNA in human sera is not informative biomarker for gastric cancer.

BACKGROUND: We aimed to ascertain if Gastrokine 1 mRNA in the sera of patients with gastric cancer might be an informative biomarker for the disease. RESULTS: Analysis of GKN1 mRNA in serum samples from healthy individuals (n = 23) and from patients with diagnosis of gastric cancer (n = 16), performed by using absolute quantification based on standard curve method, did not show any significative statistical difference between the two unpaired group of individuals. CONCLUSIONS: Our preliminary results did not confirm GKN1 as a potential biomarker for gastric cancer.

LINC00958 as new diagnostic and prognostic biomarker of childhood acute lymphoblastic leukaemia of B cells.

Background: Paediatric acute B-cell lymphoblastic leukaemia is the most common cancer of the paediatric age. Although the advancement of scientific and technological knowledge has ensured a huge step forward in the management of this disease, there are 15%-20% cases of recurrence leading to serious complications for the patient and sometimes even death. It is therefore necessary to identify new and increasingly personalised biomarkers capable of predicting the degree of risk of B-ALL in order to allow the correct management of paediatric leukaemia patients. Methods: Starting from our previously published results, we validate the expression level of LINC00958 in a cohort of 33 B-ALL and 9 T-ALL childhood patients, using in-silico public datasets as support. Expression levels of LINC00958 in B-ALL patients stratified by risk (high risk vs. standard/medium risk) and who relapsed 3 years after the first leukaemia diagnosis were also evaluated. Results: We identified the lncRNA LINC00958 as a biomarker of B-ALL, capable of discriminating B-ALL from T-ALL and healthy subjects. Furthermore, we associated LINC00958 expression levels with the disease risk classification (high risk and standard risk). Finally, we show that LINC00958 can be used as a predictor of relapses in patients who are usually stratified as standard risk and thus not always targeted for marrow transplantation. Conclusions: Our results open the way to new diagnostic perspectives that can be directly used in clinical practice for a better management of B-ALL paediatric patients.

Generation of an induced pluripotent stem cell line (CSS012-A (7672)) carrying the p.G376D heterozygous mutation in the TARDBP protein.

Amyotrophic lateral sclerosis (ALS) is an incurable neurodegenerative condition with phenotypic and genetic heterogeneity. It is characterized by the selective vulnerability and the progressive loss of the neural population. Here, an induced pluripotent stem cell (iPSC) line was generated from dermal fibroblasts of an individual carrying the p.G376D mutation in the TDP-43 protein. Fibroblasts were reprogrammed using non-integrating episomal plasmids. There were no karyotype abnormalities, and iPSCs successfully differentiated into all three germ layers. This cell line may prove useful in the study of the pathogenic mechanisms that underpin ALS syndrome.

Generation of an induced pluripotent stem cell line, CSSi011-A (6534), from an Amyotrophic lateral sclerosis patient with heterozygous L145F mutation in SOD1 gene.

Among the known causative genes of familial ALS, SOD1mutation is one of the most common. It encodes for the ubiquitous detoxifying copper/zinc binding SOD1 enzyme, whose mutations selectively cause motor neuron death, although the mechanisms are not as yet clear. What is known is that mutant-mediated toxicity is not caused by loss of its detoxifying activity but by a gain-of-function. In order to better understand the pathogenic mechanisms of SOD1 mutation, a human induced pluripotent stem cell (hiPSC) line was generated from the somatic cells of a female patient carrying a missense variation in SOD1 (L145F).

GKN1 expression in gastric cancer cells is negatively regulated by miR-544a.

Gastrokine1 (GKN1), important for maintaining the physiological function of the gastric mucosa, is highly expressed in the stomach of healthy individuals but is down-regulated or absent in gastric tumor tissues and derived cell lines. The mechanisms underlying GKN1 gene inactivation are still unknown. We previously showed that GKN1 downregulation in gastric tumors is likely associated with an epigenetic transcriptional complex that negatively regulates GKN1 expression. In addition, TSA-mediated inhibition of HDACs leads to GKN1 restoration at the transcriptional level, but no at the translational level. These findings led to hypothesize the activation of a second regulatory mechanism microRNAs-mediated, thus resulting in translational repression and gene silencing. Bioinformatic analyses performed with 5 different algorithms highlighted that 4 miRNAs contained a seed sequence for the 3'UTR of GKN1 mRNA. Among these, only two miRNAs, hsa-miR-544a and miR-1245b-3p directly target the GKN1-3'UTR as evaluated by luciferase reporter assays. TaqMan miRNA assay performed on gastric cancer cell lines after TSA treatment showed a stronger increase of miR-544a expression than that of miR-1245b-3p. Finally, co-transfection of AGS cells with GKN1-3'UTR and premiR-544a showed compared to controls, a strong reduction of GKN1 expression both at translational and transcriptional levels. The up-regulation of miR-544a could be crucially involved in the GKN1 translational repression, thus suggesting its potential role as a biomarker and therapeutic target in GC patients. These findings indicate that epigenetic mechanisms leading to the inactivation of GKN1 play a key role in the multi-step process of gastric carcinogenesis and would provide an essential starting point for the development of new therapeutic strategies based on epigenetic targets for alternatives gene.

Production and characterization of human induced pluripotent stem cells (iPSC) CSSi007-A (4383) from Joubert Syndrome.

Joubert syndrome (JS) is an autosomal recessive neurodevelopmental disorder, characterized by congenital cerebellar and brainstem defects, belonging to the group of disorders known as ciliopathies, which are caused by mutations in genes encoding proteins of the primary cilium and basal body. Human induced pluripotent stem cells (hiPSCs) from a patient carrying a homozygous missense mutation (c.2168G > A) in AHI1, the first gene to be associated with JS, were produced using a virus-free protocol.

Generation of induced pluripotent stem cell line CSSi008-A (4698) from a patient affected by advanced stage of Dentato-Rubral-Pallidoluysian atrophy (DRPLA).

Dentato-Rubral-pallidoluysian atrophy (DRPLA) is a rare autosomal, dominant, progressive neurodegenerative disease that causes involuntary movements, mental and emotional problems. DRPLA is caused by a mutation in the ATN1 gene that encodes for an abnormal polyglutamine stretch in the atrophin-1 protein. DRPLA is most common in the Japanese population, where it has an estimated incidence of 2 to 7 per million people. This condition has also been seen in families from North America and Europe. We obtained a reprogrammed iPSC line from a Caucasian patient with a juvenile onset of the disease, carrying 64 CAG repeat expansion in the ATN1 gene.

Production and characterization of CSSI003 (2961) human induced pluripotent stem cells (iPSCs) carrying a novel puntiform mutation in RAI1 gene, Causative of Smith-Magenis syndrome.

Smith-Magenis syndrome (SMS) is a complex genetic disorder characterized by developmental delay, behavioural problems and circadian rhythm dysregulation. About 90% of SMS cases are due to a 17p11.2 deletion containing retinoic acid induced1 (RAI1) gene, 10% are due to heterozygous mutations affecting RAI1 coding region. Little is known about RAI1 role.

Production and characterization of human induced pluripotent stem cells (iPSCs) from Joubert Syndrome: CSSi001-A (2850).

Joubert Syndrome (JS) is a rare autosomal recessive or X-linked condition characterized by a peculiar cerebellar malformation, known as the molar tooth sign (MTS), associated with other neurological phenotypes and multiorgan involvement. JS is a ciliopathy, a spectrum of disorders whose causative genes encode proteins involved in the primary cilium apparatus. In order to elucidate ciliopathy-associated molecular mechanisms, human induced pluripotent stem cells (hiPSCs) were derived from a patient affected by JS carrying a homozygous missense mutation in the AHI1 gene (p.H896R) that encodes a protein named Jouberin.

Copy number variations in healthy subjects. Case study: iPSC line CSSi005-A (3544) production from an individual with variation in 15q13.3 chromosome duplicating gene CHRNA7.

CHRNA7, encoding the neuronal alpha7 nicotinic acetylcholine receptor (a7nAChR), is highly expressed in the brain, particularly in the hippocampus. It is situated in the 15q13.3 chromosome region, frequently associated with a Copy Number Variation (CNV), which causes its duplication or deletion. The clinical significance of CHRNA7 duplications is unknown so far, but there are several research data suggesting that they may be pathogenic, with reduced penetrance. We have produced an iPS cell line from a single healthy donor's fibroblasts carrying a 15q13.3 CNV, including CHRNA7 in order to study the exact role of this CNV during the neurodevelopment.

Establishment of stable iPS-derived human neural stem cell lines suitable for cell therapies.

Establishing specific cell lineages from human induced pluripotent stem cells (hiPSCs) is vital for cell therapy approaches in regenerative medicine, particularly for neurodegenerative disorders. While neural precursors have been induced from hiPSCs, the establishment of hiPSC-derived human neural stem cells (hiNSCs), with characteristics that match foetal hNSCs and abide by cGMP standards, thus allowing clinical applications, has not been described. We generated hiNSCs by a virus-free technique, whose properties recapitulate those of the clinical-grade hNSCs successfully used in an Amyotrophic Lateral Sclerosis (ALS) phase I clinical trial. Ex vivo, hiNSCs critically depend on exogenous mitogens for stable self-renewal and amplification and spontaneously differentiate into astrocytes, oligodendrocytes and neurons upon their removal. In the brain of immunodeficient mice, hiNSCs engraft and differentiate into neurons and glia, without tumour formation. These findings now warrant the establishment of clinical-grade, autologous and continuous hiNSC lines for clinical trials in neurological diseases such as Huntington's, Parkinson's and Alzheimer's, among others.

Role of human GKN1 on APP processing in gastric cancer.

Gastrokine 1 (GKN1) is highly expressed in gastric tissue and is secreted into the stomach but is not expressed in gastric cancer. GKN1 belongs to the BRICHOS domain family and plays a major role in maintaining gastric mucosa integrity. We previously demonstrated that a recombinant human GKN1 protein was able to interact with the amyloid precursor protein (APP) and was endowed with an anti-amyloidogenic property because it inhibited polymerization of the Aß(1-40) peptide released from APP upon its partial hydrolysis. Here, we report that GKN1 can act as a physiological suppressor of Aß production in gastric cancer cells. GKN1 blocked the access of γ-secretase to APP, thereby facilitating the cleavage of APP by α- and ß-secretases. GKN1 directly interacted with APP C-terminal fragments, C83 and C99. In addition, it did not affect γ-secretase activity in gastric cancer cells because it did not alter Notch1 processing. GKN1-mediated inhibition of APP processing might represent a new approach for the prevention and therapy of Alzheimer's disease (AD).

Epigenetic alterations of gastrokine 1 gene expression in gastric cancer.

The gastrokine 1 (GKN1) protein is important for maintaining the physiological function of the gastric mucosa. GKN1 is down-regulated in gastric tumor tissues and derived cell lines and its over-expression in gastric cancer cells induces apoptosis, suggesting a possible role for the protein as a tumor suppressor. However, the mechanism by which GKN1 is inactivated in gastric cancer remains unknown. Here, we investigated the causes of GKN1 silencing to determine if epigenetic mechanisms such as histonic modification could contribute to its down-regulation. To this end, chromatin immunoprecipitation assays for the trimethylation of histone 3 at lysine 9 (H3K9triMe) and its specific histone-lysine N-methyltransferase (SUV39H1) were performed on biopsies of normal and cancerous human gastric tissues. GKN1 down-regulation in gastric cancer tissues was shown to be associated with high levels of H3K9triMe and with the recruitment of SUV39H1 to the GKN1 promoter, suggesting the presence of an epigenetic transcriptional complex that negatively regulates GKN1 expression in gastric tumors. The inhibition of histone deacetylases with trichostatin A was also shown to increase GKN1 mRNA levels. Collectively, our results indicate that complex epigenetic machinery regulates GKN1 expression at the transcriptional level, and likely at the translational level.

AMP18 interacts with the anion exchanger SLC26A3 and enhances its expression in gastric cancer cells.

AMP18 is a stomach-specific secreted protein expressed in normal gastric mucosa but absent in gastric cancer. AMP18 plays a major role in maintaining gastric mucosa integrity and is characterized by the presence of a BRICHOS domain consisting of about 100 amino acids, present also in several unrelated proteins, and probably endowed with a chaperon-like activity. In this work, we exploited a functional proteomic strategy to identify potential AMP18 interactors with the aim to add knowledge on its functional role within gastric cell lines and tissues. To this purpose, recombinant biotinylated AMP18 was purified and incubated with protein extract from human normal gastric mucosa by applying an affinity chromatography strategy. The interacting proteins were identified by peptide mass fingerprinting using MALDI-TOF mass spectrometry. The pool of interacting proteins contained SLC26A3, a protein expressed in the apical membrane of intestinal epithelial cells, supposed to play a critical role in Cl(-) absorption and fluid homeostasis. The interaction was also confirmed by Western blot with anti-SLC26A3 on transfected AGS cell extract following AMP18 pull-down. Furthermore, the interaction between AMP18 and SLC26A3 was also validated by confocal microscopy that showed a co-localization of both proteins at plasma membrane level. More importantly, for the first time, we showed that SLC26A3 is down-regulated in gastric cancer and that the overexpression of AMP18 in AMP-transfected gastric cancer cells up-regulated the expression of SLC26A3 both at transcriptional and translational level, the latter probably through the activation of the MAP kinases pathway. These findings strongly suggest that AMP18 might play an anti-inflammatory role in maintaining mucosal integrity also by regulating SLC26A3 level.

Ectopic expression of gastrokine 1 in gastric cancer cells up-regulates tight and adherens junction proteins network.

Gastrokine 1 (GKN1) is a stomach-specific protein important in the replenishment of the surface lumen epithelial cell layer and in maintaining mucosal integrity. A role in cell proliferation and differentiation has also been hypothesized. Despite these findings, the function(s) as well as the cellular localization of GKN1 in the cellular machinery are currently not clarified. The investigation of subcellular localization of GKN1 in gastric cancer cells can provide insights into its potential cellular roles. Subcellular fractions of gastric cancer cells (AGS) transfected with full-length GKN1 (flGKN1) or incubated with recombinant GKN1 (rGKN1) lacking the first 20 amino acids at N-terminal were analyzed by Western blot and confocal microscopy and compared with those from normal gastric tissue. Wild type GKN1 (wtGKN1) and flGKN1 were revealed in the cytoplasm and in the membrane fractions of gastric cells, whereas rGKN1 was revealed in the cytoplasmic fractions, but a high amount was detected in the membrane pellet of the AGS lysate. The cellular distribution of GKN1 was also confirmed by confocal microscopy. The purified protein was also used to highlight its possible association with actin through confocal microscopy, pelleting assay, and size-exclusion chromatography. GKN1 co-localizes with actin in normal gastric tissue, but no direct interaction was observed between the two proteins in vitro. Most likely, GKN1 indirectly participates in actin stabilization since its overexpression in gastric cancer cells strongly increases the expression of tight and adherens junction proteins.

Anti-amyloidogenic property of human gastrokine 1.

Gastrokine 1 (GKN1) is a stomach-specific protein expressed in normal gastric tissue but absent in gastric cancer. GKN1 plays a major role in maintaining gastric mucosa integrity and is characterized by the presence of a BRICHOS domain consisting of about 100 amino acids also found in several unrelated proteins associated with major human diseases like BRI2, related to familial British and Danish dementia and surfactant protein C (SP-C), associated with respiratory distress syndrome. It was reported that recombinant BRICHOS domains from BRI2 and SP-C precursor (proSP-C) prevent fibrils formation of amyloid-beta peptide (Aß), that is the major component of extracellular amyloid deposits in Alzheimer's disease. Here we investigated on the interaction between human recombinant GKN1 (rGKN1) and Aß peptide (1-40) that derives from the partial hydrolysis of the amyloid precursor protein (APP). GKN1 prevented amyloid aggregation and fibrils formation by inhibiting Aß(1-40) polymerization, as evaluated by SDS-PAGE, thioflavin-T binding assay and gel filtration experiments. Mass spectrometry showed the formation of a prevailing 1:1 complex between GKN1 and Aß(1-40). SPR analysis of GKN1/Aß interaction led to calculate a dissociation constant (KD) of 34 µM. Besides its interaction with Aß(1-40), GKN1 showed also to interact with APP as evaluated by confocal microscopy and Ni-NTA pull-down. Data strongly suggest that GKN1 has anti-amyloidogenic properties thus functioning as a chaperone directed against unfolded segments and with the ability to recognize amyloidogenic polypeptides and prevent their aggregation.

Structural characterization and biological properties of human gastrokine 1.

Gastrokine-1 (GKN1), a protein expressed in normal gastric tissue, but absent in gastric cancer tissues and derived cell lines, has recently emerged as a potential biomarker for gastric cancer. To better establish the molecular properties of GKN1, the first protocol for the production of mature human GKN1 in the expression system of Pichia pastoris was settled. The recombinant protein showed anti-proliferative properties specifically on gastric cancer cell lines thus indicating that it was properly folded. Characterization of structural and biochemical properties of recombinant GKN1 was achieved by limited proteolysis analysis, circular dichroism and fluorescence spectroscopy. The analysis of GKN1 primary structure coupled to proteolytic experiments highlighted that GKN1 was essentially resistant to proteolytic enzymes and showed the presence of at least a disulphide bond between Cys61 and one of the other three Cys (Cys122, Cys145 and Cys159) of the molecule. The secondary structure analysis revealed a prevailing ß-structure. Spectroscopic and calorimetric investigations on GKN1 thermal denaturation pointed out its high thermal stability and suggested a more complex than a two-state unfolding process. The resulting protein was endowed with a globular structure characterized by domains showing different stabilities toward chemical and physical denaturants. These results are in agreement with the prediction of GKN1 secondary structure and a three-dimensional structure model. Our findings provide the basis for the development of new pharmaceutical compounds of potential use for gastric cancer therapy.