Nitrosative stress induces DNA strand breaks but not caspase mediated apoptosis in a lung cancer cell line

BACKGROUND: Key steps crucial to the process of tumor progression are genomic instability and escape from apoptosis. Nitric oxide and its interrelated reactive intermediates (collectively denoted as NO(X)) have been implicated in DNA damage and mutational events leading to cancer development, while also being implicated in the inhibition of apoptosis through S-nitrosation of key apoptotic enzymes. The purpose of this study was to explore the interrelationship between NO(X)-mediated DNA strand breaks (DSBs) and apoptosis in cultured tumor cell lines. METHODS: Two well-characterized cell lines were exposed to increasing concentrations of exogenous NO(X )via donor compounds. Production of NO(X )was quantified by the Greiss reaction and spectrophotometery, and confirmed by nitrotyrosine immunostaining. DSBs were measured by the alkaline single-cell gel electrophoresis assay (the COMET assay), and correlated with cell viability by the MTT assay. Apoptosis was analyzed both by TUNEL staining and Annexin V/propidium iodine FACS. Finally, caspase enzymatic activity was measured using an in-vitro fluorogenic caspase assay. RESULTS: Increases in DNA strand breaks in our tumor cells, but not in control fibroblasts, correlated with the concentration as well as rate of release of exogenously administered NO(X). This increase in DSBs did not correlate with an increase in cell death or apoptosis in our tumor cell line. Finally, this lack of apoptosis was found to correlate with inhibition of caspase activity upon exposure to thiol- but not NONOate-based NO(X )donor compounds. CONCLUSIONS: Genotoxicity appears to be highly interrelated with both the concentration and kinetic delivery of NO(X). Moreover, alterations in cell apoptosis can be seen as a consequence of the explicit mechanisms of NO(X )delivery. These findings lend credence to the hypothesis that NO(X )may play an important role in tumor progression, and underscores potential pitfalls which should be considered when developing NO(X)-based chemotherapeutic agents

Molecular Mechanisms of Squamous Cell Carcinoma Tumor Stem Cell Creation via High Nitric Oxide (HNO) Adaptation

Cancer relapse or recurrence is defined as the return of cancer or its signs/symptoms after a period of improvement. Surgery may not remove all cancer cells and leave behind a few which cannot be detected by scans or other tests. It is also possible that some tumor cells are resistant to chemotherapy or radiation. Although many cancer cells are killed by these treatments, there may exist a few which contain a different genetic makeup which allows them to survive. These hypermalignant cancer cells, or cancer stem cells (CSCs), have been associated with causing cancer relapse. It has also been predicted that these CSCs are created through the adaptation of normal cancer cells (NCCs) to high amounts of the free radical nitric oxide (HNO). In the present study, we looked at the mechanisms by which normal squamous cell carcinomas become cancer stem cells via HNO adaptation. Squamous cells are thin, flat cells which line the surface of the skin, hollow organs of the body, and respiratory and digestive tracts. This study analyzed the genetic differences between cancer stem cells and their predecessors

Role of Pseudogenes in Cancer Stem Creation Via High Nitric Oxide (HNO) Adaptation

Gene chip analysis of ten HNO adapted cell lines (Squamous cells: SCC-016, SCC-040, SCC-056, SCC-114, SCC-116; Adenocarcinomas: A549, BT20, Hs578, MCF7, and T47D) was carried out. Known pseudogenes were identified in each line, as well as their coding counterparts. The adenocarcinoma cell lines had no up regulated pseudogenes, while they had the following down regulated pseudogenes: RP6-159A1.2, RP11-255N24.3, AC004490.1, LDHBP, RP11-572H4.2. The squamous cell carcinomas (SCCs) had the following up regulated pseudogenes: RPL37AP1, AC138972.1, RP11-641D5.1, AC005534.6, AC022431.1, RPL26P12, and they had these down regulated pseudogenes: RP6-159A1.2, RP11-255N24.3, RBMXP1, RP11-20O23.1, RP11-551G24.2. All cell lines adhered to the hypothesis that an increase in a pseudogene expression also had an increase in the corresponding gene. The high level of pseudogenes could be due to low levels of microRNA; low expression of microRNA could then be due to high levels of ceRNA. In cases when the pseudogenes increase in expression (possibly due to HNO interference) they, like BRAF, take the functionality of ceRNA which in turn decreases microRNA expression. Although a pseudogene may not have any direct translational significance, it can act as ceRNA to facilitate the over expression of the coding gene in a feedback loop

The Airborne Metagenome in an Indoor Urban Environment

The indoor atmosphere is an ecological unit that impacts on public health. To investigate the composition of organisms in this space, we applied culture-independent approaches to microbes harvested from the air of two densely populated urban buildings, from which we analyzed 80 megabases genomic DNA sequence and 6000 16S rDNA clones. The air microbiota is primarily bacteria, including potential opportunistic pathogens commonly isolated from human-inhabited environments such as hospitals, but none of the data contain matches to virulent pathogens or bioterror agents. Comparison of air samples with each other and nearby environments suggested that the indoor air microbes are not random transients from surrounding outdoor environments, but rather originate from indoor niches. Sequence annotation by gene function revealed specific adaptive capabilities enriched in the air environment, including genes potentially involved in resistance to desiccation and oxidative damage. This baseline index of air microbiota will be valuable for improving designs of surveillance for natural or man-made release of virulent pathogens

Nitric Oxide: Perspectives and Emerging Studies of a Well Known Cytotoxin

The free radical nitric oxide (NO•) is known to play a dual role in human physiology and pathophysiology. At low levels, NO• can protect cells; however, at higher levels, NO• is a known cytotoxin, having been implicated in tumor angiogenesis and progression. While the majority of research devoted to understanding the role of NO• in cancer has to date been tissue-specific, we herein review underlying commonalities of NO• which may well exist among tumors arising from a variety of different sites. We also discuss the role of NO• in human physiology and pathophysiology, including the very important relationship between NO• and the glutathione-transferases, a class of protective enzymes involved in cellular protection. The emerging role of NO• in three main areas of epigenetics—DNA methylation, microRNAs, and histone modifications—is then discussed. Finally, we describe the recent development of a model cell line system in which human tumor cell lines were adapted to high NO• (HNO) levels. We anticipate that these HNO cell lines will serve as a useful tool in the ongoing efforts to better understand the role of NO• in cancer

Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine

[This corrects the article DOI: 10.1186/s13054-016-1208-6.]

Labyrinthin: A distinct pan-adenocarcinoma diagnostic and immunotherapeutic tumor specific antigen

Structural analysis and detection of optimal cell surface localization of labyrinthin, a pan-adenocarcinoma target, was studied with respect to adenocarcinoma specificity vs. normal and non-adenocarcinoma cells. Patient-derived tissue microarray immunohistochemistry (IHC) was performed on 729 commercially prepared tissue blocks of lung, colon, breast, pancreas, prostate, and ovary cancers combined, plus a National Cancer Institute (NCI) tissue microarray derived from another 236 cases. The results confirmed that anti-labyrinthin mouse monoclonal MCA 44-3A6 antibody recognized adenocarcinomas, but not normal or non-adenocarcinoma cancer cells. The consensus of multiple topology analysis programs on labyrinthin (255 amino acids) estimate a type II cell membrane associated protein with an N-terminus signal peptide. However, because the labyrinthin sequence is enveloped within the 758 amino acids of the intracellular aspartyl/asparaginyl beta-hydroxylase (ASPH), a purported tumor associated antigen, standard IHC methods that permeabilize cells can expose common epitopes. To circumvent antibody cross-reactivity, cell surface labyrinthin was distinguished from intracellular ASPH by FACS analysis of permeabilized vs non-permeabilized cells. All permeabilized normal, adeno-and non-adenocarcinoma cells produced a strong MCA 44-3A6 binding signal, likely reflecting co-recognition of intracellular ASPH proteins along with internalized labyrinthin, but in non-permeabilized cells only adenocarcinoma cells were positive for labyrinthin. Confocal microscopy confirmed the FACS results. Labyrinthin as a functional cell-surface marker was suggested when: 1) WI-38 normal lung fibroblasts transfected with labyrinthin sense cDNA displayed a cancerous phenotype; 2) antisense transfection of A549 human lung adenocarcinoma cells appeared more normal; and 3) MCA44-3A6 suppressed A549 cell proliferation. Collectively, the data indicate that labyrinthin is a unique, promising adenocarcinoma tumor-specific antigen and therapeutic target. The study also raises a controversial issue on the extent, specificity, and usefulness of ASPH as an adenocarcinoma tumor-associated antigen

Topology and adenocarcinoma cell localization dataset on the labyrinthin diapeutic biomarker

Abstract Objective The discovery and characterization of tumor associated antigens is increasingly important to advance the field of immuno-oncology. In this regard, labyrinthin has been implicated as a neoantigen found on the cell surface of adenocarcinomas. Data on the (1) topology, (2) amino acid (a.a.) homology analyses and (3) cell surface localization of labyrinthin by fluorescent activated cell sorter (FACS) are studied in support of labyrinthin as a novel, pan-adenocarcinoma marker. Results Bioinformatics analyses predict labyrinthin as a type II protein with calcium binding domain(s), N-myristoylation sites, and kinase II phosphorylation sites. Sequence homologies for labyrinthin (255 a.a.) were found vs. the intracellular aspartyl/asparaginyl beta-hydroxylase (ASPH; 758 a.a.) and the ASPH-gene related protein junctate (299 a.a.), which are both type II proteins. Labyrinthin was detected by FACS on only non-permeablized A549 human lung adenocarcinoma cells, but not on normal WI-38 human lung fibroblasts nor primary cultures of normal human glandular-related cells. Microscopic images of immunofluorescent labelled MCA 44-3A6 binding to A549 cells at random cell cycle stages complement the FACS results by further showing that labyrinthin persisted on the cell surfaces along with some cell internalization for greater than 20 min

Topology and adenocarcinoma cell localization dataset on the labyrinthin diapeutic biomarker.

ObjectiveThe discovery and characterization of tumor associated antigens is increasingly important to advance the field of immuno-oncology. In this regard, labyrinthin has been implicated as a neoantigen found on the cell surface of adenocarcinomas. Data on the (1) topology, (2) amino acid (a.a.) homology analyses and (3) cell surface localization of labyrinthin by fluorescent activated cell sorter (FACS) are studied in support of labyrinthin as a novel, pan-adenocarcinoma marker.ResultsBioinformatics analyses predict labyrinthin as a type II protein with calcium binding domain(s), N-myristoylation sites, and kinase II phosphorylation sites. Sequence homologies for labyrinthin (255 a.a.) were found vs. the intracellular aspartyl/asparaginyl beta-hydroxylase (ASPH; 758 a.a.) and the ASPH-gene related protein junctate (299 a.a.), which are both type II proteins. Labyrinthin was detected by FACS on only non-permeablized A549 human lung adenocarcinoma cells, but not on normal WI-38 human lung fibroblasts nor primary cultures of normal human glandular-related cells. Microscopic images of immunofluorescent labelled MCA 44-3A6 binding to A549 cells at random cell cycle stages complement the FACS results by further showing that labyrinthin persisted on the cell surfaces along with some cell internalization for greater than 20 min