Ornithine decarboxylase antizyme inhibitor 2 (AZIN2) is a signature of secretory phenotype and independent predictor of adverse prognosis in colorectal cancer

Role of secretomes in cell-free therapeutic strategies in regenerative medicine

After an injury, peripheral nervous system neurons have the potential to rebuild their axons by generating a complicated activation response. Signals from the damaged axon are required for this genetic transition to occur. Schwann cells (SCs) near a damaged nerve's distal stump also play a role in the local modulation of axonal programs, not only via cell-to-cell contacts but also through secreted signals (the secretome). The secretome is made up of all the proteins that the cell produces, such as cytokines, growth factors, and extracellular vesicles. The released vesicles may carry signaling proteins as well as coding and regulatory RNAs, allowing for multilayer communication. The secretome of SCs is now well understood as being critical for both orchestrating Wallerian degeneration and maintaining axonal regeneration. As a consequence, secretome has emerged as a feasible tissue regeneration alternative to cell therapy. Separate SC secretome components have been used extensively in the lab to promote peripheral nerve regeneration after injury. However, in neurological therapies, the secretome generated by mesenchymal (MSC) or other derived stem cells has been the most often used. In fact, the advantages of cell treatment have been connected to the release of bioactive chemicals and extracellular vesicles, which make up MSCs' secretome.

Antizyme inhibitor family: biological and translational research implications

Metabolism of polyamines is of critical importance to physiological processes. Ornithine decarboxylase (ODC) antizyme inhibitors (AZINs) are capable of interacting with antizymes (AZs), thereby releasing ODC from ODC-AZs complex, and promote polyamine biosynthesis. AZINs regulate reproduction, embryonic development, fibrogenesis and tumorigenesis through polyamine and other signaling pathways. Dysregulation of AZINs has involved in multiple human diseases, especially malignant tumors. Adenosine-to-inosine (A-to-I) RNA editing is the most common type of post-transcriptional nucleotide modification in humans. Additionally, the high frequencies of RNA-edited AZIN1 in human cancers correlates with increase of cancer cell proliferation, enhancement of cancer cell stemness, and promotion of tumor angiogenesis. In this review, we summarize the current knowledge on the various contribution of AZINs related with potential cancer promotion, cancer stemness, microenvironment and RNA modification, especially underlying molecular mechanisms, and furthermore explored its promising implication for cancer diagnosis and treatment.

Differential and cooperative effects of IL-25 and IL-33 on T helper cells contribute to cryptococcal virulence and brain infection

The epithelial cell-derived cytokines IL-33 and IL-25 are important mediators in driving type-2 inflammation during C. neoformans infection. Nevertheless, the impact of these cytokines in regulating host T helper cell response during C. neoformans infection is still unclear. We observed that C. neoformans infection promoted a predominant increase of T helper cells that co-expressed IL-25 and IL-33 receptors within the lung during the late infection phase. A comparative transcriptomic analysis of effector T helper cells co-treated with IL-25 and IL-33 revealed a cooperative effect of these cytokines in promoting IL-13 gene expression. Without IL-25 receptor signaling, IL-33 treatment upregulated Th1-associated genes and genes associated with nucleotide metabolism. By contrast, IL-25 had a unique effect in enhancing type-2 cytokines IL-5 and IL-9 and chemokine CCL24, as well as genes in the pathways that are associated with L-arginine metabolisms. Interestingly, this pathogenic T helper cell population that expressed IL-25 and IL-33 receptors was greatly enriched in mice that were infected with high cryptococcal virulence and associated with fungal burdens in the brain. Therefore, our data further provide the additional function of IL-25 and IL-33 in potentiating cryptococcal brain dissemination.

A new 68Ga-labeled ornithine derivative for PET imaging of ornithine metabolism in tumors

Ornithine metabolism plays a vital role in tumorigenesis. For cancer cells, ornithine is mainly used as a substrate for ornithine decarboxylase (ODC) for the synthesis of polyamines. The ODC as a key enzyme of polyamine metabolism has become an important target for cancer diagnosis and treatment. To non-invasively detect the levels of ODC expression in malignant tumors, we have synthesized a novel ⁶⁸Ga-labeled ornithine derivative ([⁶⁸Ga]Ga-NOTA-Orn). The synthesis time of [⁶⁸Ga]Ga-NOTA-Orn was about 30 min with a radiochemical yield of 45-50% (uncorrected), and the radiochemical purity was > 98%. [⁶⁸Ga]Ga-NOTA-Orn was stable in saline and rat serum. Cellular uptake and competitive inhibition assays using DU145 and AR42J cells demonstrated that the transport pathway of [⁶⁸Ga]Ga-NOTA-Orn was similar to that of L-ornithine, and it could interact with the ODC after transporting into the cell. Biodistribution and micro-positron emission tomography (Micro-PET) imaging studies showed that [⁶⁸Ga]Ga-NOTA-Orn exhibited rapid tumor uptake and was rapidly excreted through the urinary system. All above results suggested that [⁶⁸Ga]Ga-NOTA-Orn is a novel amino acid metabolic imaging agent with great potential of tumor diagnosis.

AS1411 aptamer-functionalized exosomes in the targeted delivery of doxorubicin in fighting colorectal cancer

Severe side effects of chemotherapy agents on vital organs are the major causes of cancer-related mortality, not merely cancer disease. Encapsulating chemotherapeutic molecules in nanocarriers is a justifiable solution in decreasing the risk of their side effects and boosting the efficiency of treatment. The present study has developed the doxorubicin (DOX)-loaded AS1411 (anti-nucleolin) aptamer surface-functionalized exosome (DOX-Apt-Exo) to treat colorectal cancer in both in-vitro and in-vivo experimental models. HEK293-derived exosomes were loaded with DOX through the incubation method with a nearly 13% encapsulation efficiency. Afterwards, the 5-terminal carboxyl group of AS1411-aptamer was converted into amine-reactive NHS esters with EDC/NHS amide coupling chemistry before being conjugated to the amine groups on the exosome surface. DLS and TEM estimated the designed formulation (DOX-Apt-Exo) size of about 200 nm. Aptamer-binding affinity and cellular uptake of DOX-Apt-Exo by nucleolin-overexpressing cancer cells were depicted through fluorescence microscopy. Comparing the in-vitro cytotoxicity impact of DOX-loaded exosomes, either targeted or non-targeted by MTT assay, clearly verified a high effectiveness of ligand-receptor mediated target therapy. Subsequently, in-vivo experiments which were conducted on four groups of ectopic mouse models of colon cancer (5 in each group) demonstrated the tumor growth suppression through professional long-term accumulation and retention of DOX-Apt-Exo at the tumor site by ligand-receptor interaction. The results suggested that AS1411 aptamer-functionalized exosomes can be recommended as a safe and effective system to site-specific drug delivery in possible clinical applications of colon cancer.

Analysis of the Prognostic Significance and Immune Infiltration of the Amino Acid Metabolism-Related Genes in Colon Adenocarcinoma

Amino acid metabolization is verified to be a part in the progression of cancer. However, genes related to the amino acid metabolism have not been identified in colon adenocarcinoma (COAD). A systematic prognostic model of COAD becomes a pressing need. Among genes related to the amino acid metabolism, RIMKLB, ASPG, TH, MTAP, AZIN2, PSMB2, HDC, ACMSD, and PSMA8 were identified to construct a risk model. Kaplan–Meier (K–M) analyses demonstrated that the high-risk group achieved a poor prognosis. Area under the respective ROC (AUC) values indicated the robustness of the model. To highlight its clinical value, multivariate Cox was used to obtain the optimal variables to construct a nomogram. A higher tumor mutation burden was observed in the high-risk group. However, the low-risk group had a stronger immune infiltration. Seven molecular subtypes were found by consensus cluster. Twenty-two hub genes were identified related to the ESTIMATE score using WGCNA. In brief, our research constructed a stable prognostic model related to the amino acid metabolism in COAD, revealing its connection to the immune microenvironment. The model guided the outcome of COAD and the direction of immunotherapy.

GNEN-1: a spontaneously immortalized cell line from gastric neuroendocrine neoplasia

Mixed neuroendocrine-non-neuroendocrine neoplasms (MINEN) are rare tumors that consist of at least 30% of both neuroendocrine and non-neuroendocrine components. The data concerning the pathogenesis of MINEN suggest a monoclonal origin. We describe a spontaneously immortalized cell line derived from gastric MINEN called GNEN-1. Primary tumor consisted of components of high-grade neuroendocrine carcinoma and adenocarcinoma. The GNEN-1 cell line was initiated from metastatic tumor cells of peritoneal fluid and expresses a purely neuroendocrine phenotype. The GNEN-1 cell line grows as monolayers and has retained the neuroendocrine phenotype with positivity for chromogranin A in immunohistochemistry. Electron microscopy showed cytoplasmic dense core granules and axon hillocks. The karyotype revealed alterations typical of both adenocarcinoma and neuroendocrine carcinoma such as trisomy 7 and 8. GNEN-1 cells were also positive for stanniocalcin-1, a marker of poor prognosis in gastric carcinomas. Expression of several markers related to neuroendocrine tumors was found. There have been only a few studies on the pathogenesis of MINEN and management of the disease due to the rarity of this tumor type. Here we describe for the first time an immortalized cell line derived from mixed gastric NEN. The GNEN-1 line offers a tool for future research on gastric NEN.

Antizyme inhibitor 2 (AZIN2) associates with better prognosis of head and neck minor salivary gland adenoid cystic carcinoma

The key regulator of the polyamine biosynthetic pathway is ornithine decarboxylase (ODC). ODC is activated by antizyme inhibitor 1 (AZIN1) and 2 (AZIN2). AZIN1 and recently AZIN2 have been related to cancer; however, their functions in adenoid cystic carcinoma (ACC) have not been studied. We performed immunohistochemical study on minor salivary and mucous gland ACC tissue samples of patients treated at the Helsinki University Hospital (Helsinki, Finland) during 1974-2012. We scored AZIN1 and 2 immunoexpression in 42 and 45 tumor tissue samples, respectively, and correlated them with clinicopathological factors and survival. Enhanced AZIN2 expression was associated with better survival. In addition, both AZINs were seen more commonly in cribriform and tubular than in solid growth patterns. AZIN1 expression did not correlate with the studied clinicopathological factors. It seems that AZIN2 expression is higher in cancer tissue with secretory functions. In ACC tissue, high AZIN2 expression could be related to well-differentiated histological type which still has a functioning vesicle transportation system. Thus, AZIN2 could be a prognostic factor for better survival of ACC patients.

Hypoxia-induced antizyme inhibitors 2 regulates cisplatin resistance through epithelia-mesenchymal transition pathway in non-small cell lung cancer

Antizyme inhibitors 2 (AZIN2) was found to be associated with poor prognosis of patients with rectal cancer. However, no studies have reported whether AZIN2 functions in non-small cell lung cancer (NSCLC). This study aimed to investigate the role of AZIN2 in cisplatin (DDP) resistance in NSCLC. We established DDP resistant A549 and H1299 cell lines. The transcriptional and translational expression levels were examined using quantitative real-time polymerase chain reaction and western blot. Cell apoptosis was evaluated by caspase-3 activity and nucleosome ELISA assays. Luciferase reporter assay was employed to evaluate the impact of hypoxia-inducible factor (HIF-1α) on AZIN2 transcription. AZIN2 expression was found to be associated with DDP resistance and poor prognosis in patients with NSCLC. AZIN2 overexpression promoted cell viability, colony formation, and reduced cell apoptosis in H1299 cells and A549 upon DDP treatment. Correspondingly, AZIN2 knockdown significantly inhibited cell viability and colony formation, and increased cell apoptosis upon DDP treatment. Interestingly, AZIN2 expression in NSCLC cells was significantly induced by hypoxia condition. The occupancy of HIF-1α, an important regulator of the hypoxia response, remarkably enriched at the promoter region of AZIN2 under hypoxia condition. In addition, AZIN2 overexpression resulted in epithelial-mesenchymal transition (EMT). The results suggested that hypoxia-induced AZIN2 high expression may contribute to DDP resistance development by promoting the EMT.

Role of Antizyme Inhibitor Proteins in Cancers and Beyond

Polyamines are multivalent organic cations essential for many cellular functions, including cell growth, differentiation, and proliferation. However, elevated polyamine levels are associated with a slew of pathological conditions, including multiple cancers. Intracellular polyamine levels are primarily controlled by the autoregulatory circuit comprising two different protein types, Antizymes (OAZ) and Antizyme Inhibitors (AZIN), which regulate the activity of the polyamine biosynthetic enzyme ornithine decarboxylase (ODC). While OAZ functions to decrease the intracellular polyamine levels by inhibiting ODC activity and exerting a negative control of polyamine uptake, AZIN operates to increase intracellular polyamine levels by binding and sequestering OAZ to relieve ODC inhibition and to increase polyamine uptake. Interestingly, OAZ and AZIN exhibit autoregulatory functions on polyamine independent pathways as well. A growing body of evidence demonstrates the dysregulation of AZIN expression in multiple cancers. Additionally, RNA editing of the Azin1 transcript results in a "gain-of-function" phenotype, which is shown to drive aggressive tumor types. This review will discuss the recent advances in AZIN's role in cancers via aberrant polyamine upregulation and its polyamine-independent protein regulation. This report will also highlight AZIN interaction with proteins outside the polyamine biosynthetic pathway and its potential implication to cancer pathogenesis. Finally, this review will reveal the protein interaction network of AZIN isoforms by analyzing three different interactome databases.

Distribution of Important Probiotic Genes and Identification of the Biogenic Amines Produced by Lactobacillus acidophilus PNW3

The genome of Lactobacillus acidophilus PNW3 was assessed for probiotic and safety potentials. The genome was completely sequenced, assembled using SPAdes, and thereafter annotated with NCBI prokaryotic genome annotation pipeline (PGAP) and rapid annotation using subsystem technology (RAST). Further downstream assessment was determined using appropriate bioinformatics tools. The production of biogenic amines was confirmed through HPLC analysis and the evolutionary trend of the strain was determined through the Codon Tree pipeline. The strain was predicted as a non-human pathogen. A plethora of encoding genes for lactic acids and bioactive peptides production, adhesion molecules, resistance to the harsh gut environmental conditions, and improvement of the host metabolism, which are putative for important probiotic functionalities, were located at different loci within the genome. A bacteriocin predicted to be helveticin J was identified as one of the secondary metabolites. The maximum zone of inhibition exhibited by the crude bacteriocin against STEC E. coli O177 was 21.7 ± 0.58 mm and 24.3 ± 1.15 mm after partial purification (250 µg/mL). Three coding sequences were identified for insertion sequences and one for the CRISPR-Cas fragment. The protein-encoding sequence for Ornithine decarboxylase was found within the genome. L. acidophilus PNW3 presents important features categorizing it as a viable and safe probiotic candidate, though further safety investigations are necessary. The application of probiotics in livestock-keeping would ensure improved public health and food security.

Tetraspanin CD63 independently predicts poor prognosis in colorectal cancer

CD63, a member of the tetraspanin family, is expressed in endosomes and enriched in exosomes. Tetraspanins participate in a variety of physiological processes, including cellular differentiation, cell-cell fusion, and cell migration. CD63 reportedly carries both protumorigenic and tumor suppressor properties, and appears to be upregulated in breast cancer, astrocytoma, and melanoma. Yet, the effect of CD63 on cancer prognosis remains unclear, and no previous reports examined it in colorectal cancer (CRC). Identifying novel biomarkers will allow us to better differentiate patients with an increased risk of recurrence and who might benefit from adjuvant therapy. We applied immunohistochemistry with antibodies to human CD63 on 620 consecutive CRC patients treated at the Helsinki University Hospital. We evaluated the associations between CD63 expression and clinicopathological parameters and patient prognosis. We found that CD63 expression associated with an advanced stage, poor differentiation, and mucinous histology. We found no association between CD63 expression and age, sex or tumor location. CD63 expression predicted an unfavorable prognosis in CRC (p=0.00001, log-rank test) and in a subgroup of patients with metastasized CRC (p=0.011). Cox's multivariate analysis identified CD63 as an independent factor predicting an unfavorable prognosis in CRC and in the subgroup with metastasized disease. We show for the first time that CD63 immunohistochemistry expression represents an independent marker of an unfavorable prognosis in CRC and associates with unfavorable clinicopathological parameters. Our results support the hypothesis that a higher tissue expression of CD63 in CRC, indicating an epithelial-to-mesenchymal transition (EMT)-associated secretory phenotype, associated with an adverse outcome.