High expression of nitric oxide synthases is a favorable prognostic sign in non-small cell lung carcinoma

DOX-PLGA Nanoparticles Effectively Suppressed the Expression of Pro-Inflammatory Cytokines TNF-a, IL-6, iNOS, and IL-1β in MCF-7 Breast Cancer Cell Line

Background

Inflammation contributes to cancer pathobiology through different mechanisms. Higher levels of pro-inflammatory cytokines can lead to hyperinflammation and promote cancer development and metastasis. For cancer treatment, Doxorubicin (DOX) can be encapsulated into the poly-lactic-glycolic acid (PLGA) nanoparticles. This study aimed to investigate the impact of doxorubicin-loaded PLGA nanoparticles (DOX-PLGA NP) on the expression of pro-inflammatory genes TNF-α, IL-6, iNOS, and IL-1β in the MCF-7 cells.

Methods

The DOX-PLGA NP was prepared by loading doxorubicin into PLGA and characterized using dynamic light scattering (DLS) and atomic force microscopy (AFM). The cytotoxic effect of the nanoparticles was determined by the MTT assay, and their impacts on the expression of pro-inflammatory genes were assessed by qRT-PCR.

Results

The encapsulation efficiency and loading capacity were 60±1.5 and 1.13±0.21 percent, respectively. The zeta potential and mean DOX-PLGA nanoparticle size were -18±0.550 mV and 172±55.6 nm, respectively. The 50% inhibitory concentration (IC50) of the DOX-PLGA NP on MCF-7 cell viability was 24.55 µg/mL after 72 hours of treatment. The qRT-PCR results revealed that the 20 µg/mL concentration of the DOX-PLGA NP significantly suppressed the expression of the pro-inflammatory genes TNF-α, IL-6, iNOS, and IL-1β compared to DOX alone (20 µg/mL). Additionally, the suppression effect of DOX-PLGA NP on the expression of these pro-inflammatory genes was dose-dependent.

Conclusions

These results show that DOX-PLGA NP efficiently suppressed the expression of pro-inflammatory genes. Furthermore, encapsulation of DOX into PLGA nanoparticles significantly improved the effectiveness of DOX in suppressing pro-inflammatory genes in MCF-7 breast cancer cells.

The expression profiles of chemokines, innate immune and apoptotic genes in tumors caused by Rous Sarcoma Virus (RSV-A) in chickens

Innate immune genes play an important role in the immune responses to Rous sarcoma virus (RSV)-induced tumor formation and metastasis. Here, we determined in vivo expression of chemokines, innate immune and apoptotic genes in Synthetic Broiler Dam Line (SDL) chickens following RSV-A infection. The mRNA expression of genes was determined at the primary site of infection and in different organs of progressor, regressor and non-responder chicks, using RT-qPCR. Our results indicated a significant upregulation of: (1) chemokines, such as MIP1β and RANTES, (2) the innate immune gene TLR4, and (3) p53, a tumor-suppressor gene, at the site of primary infection in progressor chickens. In contrast, inducible nitric oxide synthase (iNOS) gene expression was significantly downregulated in progressor chicks compared to uninfected, control chicks. All of the innate immune genes were significantly upregulated in the lungs and liver of the progressor and regressor chicks compared to control chicks. In the spleen of progressor chicks, RANTES, iNOS and p53 gene expression were significantly increased, whereas MIP1β and TLR4 gene expression was significantly downregulated, compared to control chicks. The lungs and livers of non-responder chicks expressed a low level of iNOS and MIP1β, whereas RANTES, TLR4, and p53 gene expression were significantly upregulated compared to uninfected control chicks. In addition, there was a significant downregulation of RANTES, MIP1β, and TLR4 gene expression in non-responder chicks. These results suggest the different response to infection of chicks with RSV-A is due to differential changes in the expression of innate immune genes in different organs.

Targeting Metabolism to Control Immune Responses in Cancer and Improve Checkpoint Blockade Immunotherapy

Over the past decade, advances in cancer immunotherapy through PD1-PDL1 and CTLA4 immune checkpoint blockade have revolutionized the management of cancer treatment. However, these treatments are inefficient for many cancers, and unfortunately, few patients respond to these treatments. Indeed, altered metabolic pathways in the tumor play a pivotal role in tumor growth and immune response. Thus, the immunosuppressive tumor microenvironment (TME) reprograms the behavior of immune cells by altering their cellular machinery and nutrient availability to limit antitumor functions. Today, thanks to a better understanding of cancer metabolism, immunometabolism and immune checkpoint evasion, the development of new therapeutic approaches targeting the energy metabolism of cancer or immune cells greatly improve the efficacy of immunotherapy in different cancer models. Herein, we highlight the changes in metabolic pathways that regulate the differentiation of pro- and antitumor immune cells and how TME-induced metabolic stress impedes their antitumor activity. Finally, we propose some drug strategies to target these pathways in the context of cancer immunotherapy.

Macrophage Reprogramming and Cancer Therapeutics: Role of iNOS-Derived NO

Nitric oxide and its production by iNOS is an established mechanism critical to tumor promotion or suppression. Macrophages have important roles in immunity, development, and progression of cancer and have a controversial role in pro- and antitumoral effects. The tumor microenvironment consists of tumor-associated macrophages (TAM), among other cell types that influence the fate of the growing tumor. Depending on the microenvironment and various cues, macrophages polarize into a continuum represented by the M1-like pro-inflammatory phenotype or the anti-inflammatory M2-like phenotype; these two are predominant, while there are subsets and intermediates. Manipulating their plasticity through programming or reprogramming of M2-like to M1-like phenotypes presents the opportunity to maximize tumoricidal defenses. The dual role of iNOS-derived NO also influences TAM activity by repolarization to tumoricidal M1-type phenotype. Regulatory pathways and immunomodulation achieve this through miRNA that may inhibit the immunosuppressive tumor microenvironment. This review summarizes the classical physiology of macrophages and polarization, iNOS activities, and evidence towards TAM reprogramming with current information in glioblastoma and melanoma models, and the immunomodulatory and therapeutic options using iNOS or NO-dependent strategies.

CHID1 Is a Novel Prognostic Marker of Non-Small Cell Lung Cancer

There is an urgent need for identification of new prognostic markers and therapeutic targets for non-small cell lung cancer (NSCLC). In this study, we evaluated immune cells markers in 100 NSCLC specimens. Immunohistochemical analysis revealed no prognostic value for the markers studied, except CD163 and CD206. At the same time, macrophage markers iNOS and CHID1 were found to be expressed in tumor cells and associated with prognosis. We showed that high iNOS expression is a marker of favorable prognosis for squamous cell lung carcinoma (SCC), and NSCLC in general. Similarly, high CHID1 expression is a marker of good prognosis in adenocarcinoma and in NSCLC in general. Analysis of prognostic significance of a high CHID1/iNOS expression combination showed favorable prognosis with 20 months overall survival of patients from the low CHID1/iNOS expression group. For the first time, we demonstrated that CHID1 can be expressed by NSCLC cells and its high expression is a marker of good prognosis for adenocarcinoma and NSCLC in general. At the same time, high expression of iNOS in tumor cells is a marker of good prognosis in SCC. When used in combination, CHID1 and iNOS show a very good prognostic capacity for NSCLC. We suggest that in the case of lung cancer, tumor-associated macrophages are likely ineffective as a therapeutic target. At the same time, macrophage markers expressed by tumor cells may be considered as targets for anti-tumor therapy or, as in the case of CHID1, as potential anti-tumor agents.

Novel somatic alterations underlie Chinese papillary thyroid carcinoma

To characterize the somatic alterations of papillary thyroid carcinomas (PTC) in Chinese patients, we performed the next-generation-sequencing (NGS) study of the tumor-normal pairs of DNA and RNA samples extracted from 16 Chinese PTC patients. The whole genome sequencing (WGS) and transcriptome sequencing (RNA-seq) were conducted for 6 patients who were either current or former smokers and the whole exome sequencing (WES) and RNA-seq were conducted for another 10 patients who were never smokers. The NGS data were analyzed to identify somatic alteration events that may underlie PTC in Chinese patients. We identified a number of PTC driver genes harboring somatic driver mutations with significant functional impact such as COL11A1, TP53, PLXNA4, UBA1, AHNAK, CSMD2 and TTLL5 etc. Significant driver pathways underlying PTC were found, namely, the metabolic pathway, the pathway in cancer, the olfactory transduction pathway and the calcium signaling pathway. In addition, this study revealed genes with significant somatic copy number aberrations and corresponding somatic gene expression changes in PTC tumors, the most promising ones being BRD9, TRIP13, FZD3, and TFDP1 etc. We also identified several structural variants of PTCs, especially the novel in-frame fusion proteins such as TRNAU1AP-RCC1, RAB3GAP1-R3HDM1, and ENAH-ZSWIM5. Our study provided a list of novel PTC candidate genes with somatic alterations that may function as biomarkers for PTC in Chinese patients. The follow-up mechanism studies may be conducted based on the findings from this study.

iNOS Expression by Tumor-Infiltrating Lymphocytes, PD-L1 and Prognosis in Non-Small-Cell Lung Cancer

Simple Summary

The role of Inducible Nitric Oxygen Synthase (iNOS) in the progression of human malignancies is obscure. We studied the expression patterns of iNOS in non-small-cell lung cancer. iNOS was expressed by cancer cells and cancer-associated fibroblasts. None of these patterns, however, are related to stage or prognosis. Extensive infiltration of the tumor stroma by iNOS-expressing tumor-infiltrating lymphocytes (^iNOS+TILs) occurred in 48% of cases. This was related to low Hypoxia-Inducible Factor 1α (HIF1α) and better overall survival. Expression of Programmed death-ligand 1 PD-L1, however, mitigates the beneficial effect of the presence of ^iNOS+TIL. An important role of iNOS in anti-neoplastic lymphocyte biology has been brought forward, supporting ^iNOS+TILs as putative immune response markers.

Abstract

Background: Inducible Nitric Oxygen Synthase (iNOS) promotes the generation of NO in tissues. Its role in tumor progression and immune response is unclear. Methods: The immunohistochemical expression patterns of iNOS were studied in a series of 98 tissue samples of non-small-cell lung carcinoma (NSCLC), in parallel with the expression of hypoxia and anaerobic metabolism markers, PD-L1 and tumor-infiltrating lymphocytes (TILs). Results: iNOS is expressed by cancer cells in 19/98 (19.4%), while extensive expression by cancer-associated fibroblasts occurs in 8/98 (8.2%) cases. None of these patterns relate to stage or prognosis. Extensive infiltration of the tumor stroma by iNOS-expressing TILs (^iNOS+TILs) occurs in 47/98 (48%) cases. This is related to low Hypoxia-Inducible Factor 1α (HIF1α), high PD-L1 expression and a better overall survival (p = 0.002). Expression of PD-L1, however, mitigates the beneficial effect of the presence of ^iNOS+TIL. Conclusions: Extensive expression of iNOS by TILs occurs in approximately 50% of NSCLCs, and this is significantly related to an improved overall survival. This brings forward the role of iNOS in anti-neoplastic lymphocyte biology, supporting ^iNOS+TILs as a putative marker of immune response. The value of this biomarker as a predictive and treatment-guiding tool for tumor immunotherapy demands further investigation.

Lung Microbiome Differentially Impacts Survival of Patients with Non-Small Cell Lung Cancer Depending on Tumor Stroma Phenotype

The link between a lung tumor and the lung microbiome is a largely unexplored issue. To investigate the relationship between a lung microbiome and the phenotype of an inflammatory stromal infiltrate, we studied a cohort of 89 patients with non-small cell lung cancer. The microbiome was analyzed in tumor and adjacent normal tissue by 16S rRNA amplicon sequencing. Characterization of the tumor stroma was done using immunohistochemistry. We demonstrated that the bacterial load was higher in adjacent normal tissue than in a tumor (p = 0.0325) with similar patterns of taxonomic structure and alpha diversity. Lung adenocarcinomas did not differ in their alpha diversity from squamous cell carcinomas, although the content of Gram-positive bacteria increased significantly in the adenocarcinoma group (p = 0.0419). An analysis of an inflammatory infiltrate of tumor stroma showed a correlation of CD68, iNOS and FOXP3 with a histological type of tumor. For the first time we showed that high bacterial load in the tumor combined with increased iNOS expression is a favorable prognostic factor (HR = 0.1824; p = 0.0123), while high bacterial load combined with the increased number of FOXP3+ cells is a marker of poor prognosis (HR = 4.651; p = 0.0116). Thus, we established that bacterial load of the tumor has an opposite prognostic value depending on the status of local antitumor immunity.

Tumor associated macrophages and 'NO'

Nitric oxide (NO) and its pro and anti-tumor activities are dual roles that continue to be debated in cancer biology. The cell situations in the tumor and within the tumor microenvironment also have roles involving NO. In early tumorigenic events, macrophages in the tumor microenvironment promote tumor cell death, and later are reprogramed to support the growth of tumor, through regulatory events involving NO and several stimulatory signals. These two opposing and active phenotypes of tumor associated macrophages known as the M1 or anti-tumorigenic state and M2 or pro-tumorigenic state show differences in metabolic pathways such as glycolysis and arginine utilization, signaling pathways and cytokine induction including iNOS expression, therefore contributing to their function. Polarization of M2 to M1 macrophages, inhibition of M2 state, or reprogramming via NO in combination with other signals may determine or alter tumor kinetics. These strategies and an overview are presented.

Update on emerging biomarkers in lung cancer

There has been considerable progress made in identifying oncogenic driver mutations in advanced lung cancer. The recognition that lung cancer is actually an umbrella classification that is comprised of multiple molecular subgroups has had a profound impact on how medical oncologists make treatment decisions. These mutations are clinically important as available targeted therapies can achieve significant responses and prolonged disease control. This review will summarize the current guidelines for biomarker testing and available therapeutic agents.

Systems pharmacology uncover the mechanism of anti-non-small cell lung cancer for Hedyotis diffusa Willd

Non-small cell lung cancer (NSCLC) has become one of the most general malignancies in the world and has been shown to be the leading cause of cancer-related deaths. Traditional Chinese medicine (TCM) is considered to be a useful medicine for survival, and has been used in Asia for thousands of years. Hedyotis diffusa Willd (HDW) is an important folk herb that is used in clinical treatment of various cancers in various Chinese medicine prescriptions. However, its underlying mechanism of action remains unclear. Presently, we used an innovative system-pharmacology platform to systematically uncover the pharmacological mechanisms of HDW in the treatment of NSCLC from molecules, targets, and pathway levels. The results show that HDW treatment of NSCLC may activate immunity, achieve anti-inflammatory, anti-proliferative and anti-migration therapeutic effects by regulating multiple pathways. This research provides a new idea for understanding the mechanism of TCM and promotes to develop potential drugs from HDW in modern medicine.

Role of Oxidative Stress in the Suppression of Immune Responses in Peripheral Blood Mononuclear Cells Exposed to Combustible Tobacco Product Preparation

Cigarette smoking is a major risk factor for several human diseases. Chronic inflammation, resulting from increased oxidative stress, has been suggested as a mechanism that contributes to the increased susceptibility of smokers to cancer and microbial infections. We have previously shown that whole-smoke conditioned medium (WS-CM) and total particulate matter (TPM) prepared from Kentucky 3R4F reference cigarettes [collectively called as combustible tobacco product preparations (TPPs)] potently suppressed agonist-stimulated cytokine secretion and target cell killing in peripheral blood mononuclear cells (PBMCs). Here we have investigated the role of oxidative stress from TPPs, which alters inflammatory responses in vitro. Particularly, we investigated the mechanisms of WS-CM-induced suppression of select cytokine secretions in Toll-like receptor (TLR) agonist-stimulated cells and target cell killing by effector cells in PBMCs. Pretreatment with N-acetyl cysteine (NAC), a precursor of reduced glutathione and an established anti-oxidant, protected against DNA damage and cytotoxicity caused by exposure to WS-CM. Similarly, secretion of tumor necrosis factor (TNF), interleukin (IL)-6, and IL-8 in response to TLR-4 stimulation was restored by pretreatment with NAC. Target cell killing, a functional measure of cytolytic cells in PBMCs, is suppressed by WS-CM. Pretreatment with NAC restored the target cell killing in WS-CM treated PBMCs. This was accompanied by higher perforin levels in the effector cell populations. Collectively, these data suggest that reducing oxidative stress caused by cigarette smoke components restores select immune responses in this ex vivo model.

Association of endothelial nitric oxide synthase (eNOS) polymorphisms with EGFR-mutated lung adenocarcinoma in Taiwan

EGFR mutation of Non-small cell lung cancers (NSCLC) was predominantly seen in Asian population and it was considered as a predictor of responsiveness. Eendothelial nitric oxide synthase (eNOS) plays a vital role in chronic inflammation and carcinogenesis. In this study, we aimed to explore the association between the genetic polymorphisms of eNOS (-786T/C and 894 G/T) and EGFR mutation in patients with lung adenocarcinoma. A total of 277 patients with diagnosed lung adenocarcinoma were recruited between years 2012 and 2015. All study subjects underwent the analysis of eNOS genetic variants (-786 T/C and 894 G/T) using real-time polymerase chain reaction (PCR) genotyping. Our results showed that, among the 277 patients, variant types (GT + TT) of eNOS 894 G/T polymorphism were significantly positively correlated with EGFR mutation type, specifically exon 19 in-frame deletion. With the subgroup of EGFR L858R mutation, variant genotypes (GT + TT) of eNOS 894 G/T were significantly associated with lymph node invasion. Moreover, in silico analysis indicated that eNOS 894 G/T altered the eNOS expression. In conclusion, our study showed that eNOS 894 G/T variants were significantly associated with EGFR mutation types of lung adenocarcinoma, specifically exon 19 in-frame deletion. This may be utilized as a prediction of tumor invasiveness and therapy responsiveness.

The dichotomous role of H2S in cancer cell biology? Déjà vu all over again

Nitric oxide (NO) a gaseous free radical is one of the ten smallest molecules found in nature, while hydrogen sulfide (H2S) is a gas that bears the pungent smell of rotten eggs. Both are toxic yet they are gasotransmitters of physiological relevance. There appears to be an uncanny resemblance between the general actions of these two gasotransmitters in health and disease. The role of NO and H2S in cancer has been quite perplexing, as both tumor promotion and inflammatory activities as well as anti-tumor and antiinflammatory properties have been described. These paradoxes have been explained for both gasotransmitters in terms of each having a dual or biphasic effect that is dependent on the local flux of each gas. In this review/commentary, I have discussed the major roles of NO and H2S in carcinogenesis, evaluating their dual nature, focusing on the enzymes that contribute to this paradox and evaluate the pros and cons of inhibiting or inducing each of these enzymes.

iNOS-derived nitric oxide promotes glycolysis by inducing pyruvate kinase M2 nuclear translocation in ovarian cancer

Aerobic glycolysis is essential for tumor growth and survival. Activation of multiple carcinogenic signals contributes to metabolism reprogramming during malignant transformation of cancer. Recently nitric oxide has been noted to promote glycolysis but the mechanism remains elusive. We report here the dual role of nitric oxide in glycolysis: low/physiological nitric oxide (≤ 100 nM) promotes glycolysis for ATP production, oxidative defense and cell proliferation of ovary cancer cells, whereas excess nitric oxide (≥ 500 nM) inhibits it. Nitric oxide has a positive effect on glycolysis by inducing PKM2 nuclear translocation in an EGFR/ERK2 signaling-dependent manner. Moreover, iNOS induced by mild inflammatory stimulation increased glycolysis and cell proliferation by producing low doses of nitric oxide, while hyper inflammation induced iNOS inhibited it by producing excess nitric oxide. Finally, iNOS expression is abnormally increased in ovarian cancer tissues and is correlated with PKM2 expression. Overexpression of iNOS is associated with aggressive phenotype and poor survival outcome in ovarian cancer patients. Our study indicated that iNOS/NO play a dual role of in tumor glycolysis and progression, and established a bridge between iNOS/NO signaling pathway and EGFR/ERK2/PKM2 signaling pathway, suggesting that interfering glycolysis by targeting the iNOS/NO/PKM2 axis may be a valuable new therapeutic approach of treating ovarian cancer.

The Potential Role of Nitric Oxide in Halting Cancer Progression Through Chemoprevention

Nitric oxide (NO) in general plays a beneficial physiological role as a vasorelaxant and the role of NO is decided by its concentration present in physiological environments. NO either facilitates cancer-promoting characters or act as an anti-cancer agent. The dilemma in this regard still remains unanswered. This review summarizes the recent information on NO and its role in carcinogenesis and tumor progression, as well as dietary chemopreventive agents which have NO-modulating properties with safe cytotoxic profile. Understanding the molecular mechanisms and cross-talk modulating NO effect by these chemopreventive agents can allow us to develop better therapeutic strategies for cancer treatment.

The dual role of iNOS in cancer

Nitric oxide (NO) is one of the 10 smallest molecules found in nature. It is a simple gaseous free radical whose predominant functions is that of a messenger through cGMP. In mammals, NO is synthesized by the enzyme nitric oxide synthase (NOS) of which there are three isoforms. Neuronal (nNOS, NOS1) and endothelial (eNOS, NOS3) are constitutive calcium-dependent forms of the enzyme that regulate neural and vascular function respectively. The third isoform (iNOS, NOS2), is calcium-independent and is inducible. In many tumors, iNOS expression is high, however, the role of iNOS during tumor development is very complex and quite perplexing, with both promoting and inhibiting actions having been described. This review will aim to summarize the dual actions of iNOS-derived NO showing that the microenvironment of the tumor is a contributing factor to these observations and ultimately to cellular outcomes.

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NO is pro- and anti-tumorigenic. High concentrations of NO maybe anti-tumorigenic.

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iNOS produces high concentrations of NO and relates to tumor growth or its inhibition.

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iNOS is associated with cytotoxicity, apoptosis and bystander anti-tumor effects.

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Tumor- and stromal-iNOS, and the ‘cell situation’ contribute to anti or pro-tumor effects.

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Dual role of iNOS is influenced by the cell situation and is environment dependent.

Nitric oxide induces cancer stem cell-like phenotypes in human lung cancer cells

Even though tremendous advances have been made in the treatment of cancers during the past decades, the success rate among patients with cancer is still dismal, largely because of problems associated with chemo/radioresistance and relapse. Emerging evidence has indicated that cancer stem cells (CSCs) are behind the resistance and recurrence problems, but our understanding of their regulation is limited. Rapid reversible changes of CSC-like cells within tumors may result from the effect of biological mediators found in the tumor microenvironment. Here we show how nitric oxide (NO), a key cellular modulator whose level is elevated in many tumors, affects CSC-like phenotypes of human non-small cell lung carcinoma H292 and H460 cells. Exposure of NO gradually altered the cell morphology toward mesenchymal stem-like shape. NO exposure promoted CSC-like phenotype, indicated by increased expression of known CSC markers, CD133 and ALDH1A1, in the exposed cells. These effects of NO on stemness were reversible after cessation of the NO treatment for 7 days. Furthermore, such effect was reproducible using another NO donor, S-nitroso-N-acetylpenicillamine. Importantly, inhibition of NO by the known NO scavenger 2-(4-carboxy-phenyl)-4,4,5,5 tetramethylimidazoline-1-oxy-3-oxide strongly inhibited CSC-like aggressive cellular behavior and marker expression. Last, we unveiled the underlying mechanism of NO action through the activation of caveolin-1 (Cav-1), which is upregulated by NO and is responsible for the aggressive behavior of the cells, including anoikis resistance, anchorage-independent cell growth, and increased cell migration and invasion. These findings indicate a novel role of NO in CSC regulation and its importance in aggressive cancer behaviors through Cav-1 upregulation.

The (CCTTT)n microsatellite polymorphism in the NOS2 gene may influence lung cancer risk and long-term survival, especially in non-smokers

We analyzed the associations of the NOS2 (CCTTT)n promoter polymorphism to lung cancer risk and tumor histology in smokers and non-smokers. We also investigated lung cancer long-term survival in relation to the polymorphism, smoking data, histology, age at diagnosis, and gender. One hundred eighty-five lung-cancer patients and 164 matched controls, where non-smokers were enriched among the lung cancer cases, were genotyped by fragment analysis and sequencing. Genotypes were combined with information on histology, patient smoking status, and cancer-specific death, using a 20-year follow-up. We divided the (CCTTT)n alleles into short (n ≤ 10), intermediate (n = 11-12), and long (n ≥ 13). Patients homozygous for short repeats had significantly increased risk of lung cancer (p = 0.030) compared to carriers of two long alleles (LL). Lack of long allele was associated with a significantly increased lung cancer risk overall (p = 0.011), especially among non-smokers (p = 0.001). A significantly higher lung cancer survival was seen in non-smokers compared to smokers (p = 0.046) and in low-dose smokers compared to high-dose smokers at the time of diagnosis (p = 0.028). Moreover, non-smoking patients with squamous cell carcinoma (p = 0.015) or adenocarcinoma (p = 0.024) showed a significantly lower survival compared to other lung carcinomas. Nitric oxide can induce proliferation as well as apoptosis depending on cellular context. Our results suggest that the (CCTTT)n NOS2 microsatellite may influence the risk of developing lung cancer, especially in non-smokers, possibly by affecting intracellular nitric oxide levels. Our results also give additional information about the yet poorly understood etiological and prognostic differences between lung cancer in non-smokers and smokers.

The role of macrophages polarization in predicting prognosis of radically resected gastric cancer patients

Tumour-associated Macrophages (TAM) present two different polarizations: classical (M1) characterized by immunostimulation activity and tumour suppression; alternative (M2) characterized by tumour promotion and immune suppression. In this retrospective study, we evaluated the correlation between the two forms of TAM with survival time in radically resected gastric cancer patients. A total of 52 chemo- and radio-naive patients were included. Two slides were prepared for each patient and double-stained for CD68/NOS2 (M1) or CD68/CD163 (M2) and five representative high-power fields per slide were evaluated for TAM count. The median value of the two macrophage populations density and the median value of M1/M2 ratio were used as cut-off. Twenty-seven patients with M1 density above-the-median had a significantly higher survival compared to those below the median. Twenty-six patients with M1/M2 ratio above the median showed median OS of 27.2 months compared to 15.5 months of the patients below the median. No association between M2 macrophage density and patient's outcome was found. In multivariate analysis, M1/M2 was a positive independent predictor of survival. The M1 macrophage density and M1/M2 ratio, as confirmed in multivariate analysis, are factors that can help in predicting patients survival time after radical surgery for gastric cancer.

Tumor associated macrophages polarization dictates the efficacy of BCG instillation in non-muscle invasive urothelial bladder cancer

BACKGROUND

To evaluate the prognostic role of TAMs in patients affected by non-muscle invasive bladder cancer (NMIBC), undergone Trans Urethral Resection of Bladder (TURB) and Bacillus Calmette-Guerin (BCG) therapy.

METHODS

Data from 40 patients (36 men, 4 women), mean age 69 years (40-83 years), treated for NMIBC with TURB and BCG instillation were collected. Two different groups were considered: group with and group without bladder cancer recurrence. Correlations between immunofluorescence measured Mtot, M1 and M2 infiltration and clinicopathological parameters were evaluated using Spearman and Mann-Whitney methods. The recurrence-free survival rate was calculated using the Kaplan-Meier method.

RESULTS

CD68 positive cells (Mtot) were observed in all specimens tested. High Mtot, M1 and M2 infiltration was observed in patients with disease recurrence, even before endovescical BCG instillation. Significant value for M2 infiltration (p = 0,042) was found calculating significativity between two group medians before BCG therapy. p = 0,072 and p = 0,180 were observed correlating median of Mtot and M1 between two groups of patients respectively. Values of p = 0,44, p = 0,23 and p = 0,64 from correlation between DFS and Mtot, M1 and M2 median in patients before endovescical BCG instillation, were calculated respectively. Comparing DFS and Mtot, M1 and M2 median in patients group after endovescical BCG instillation significant values were obtained (p = 0,020; p = 0,02; and p = 0,029 respectively).

CONCLUSIONS

M2 tumor infiltration could be a prognostic value of recurrence in patients with NMIBC.

Inducible nitric oxide synthase expression in gastric adenocarcinoma: impact on lymphangiogenesis and lymphatic metastasis

Background

Lymphatic metastasis is the most important parameter in the spread of gastric carcinomas. Nitric oxide (NO) is a signaling molecule that plays an important role in inflammation and carcinogenesis. In this study, the possible link between inducible nitric oxide synthase (iNOS) expression with lymphangiogenesis and the clinicopathological parameters of gastric carcinomas was investigated.

Methods

In this study, iNOS expression and D2-40 (lymphatic endothelium-specific marker monoclonal antibody) reactivity were examined immunohistochemically in 41 gastric adenocarcinoma and 20 non-neoplastic gastric tissues. iNOS expression was scored semiquantitatively in the tumor parenchyma and stroma. D2-40-positive lymphatic vessels were used in the determination of lymphatic invasion and intratumoral and peritumoral lymphatic vascular density.

Results

iNOS expression was higher in gastric carcinoma tissue compared with non-neoplastic tissue. Particularly, iNOS expression in tumor cells was found to be closely related to lymphangiogenesis and lymphatic metastasis. The density of lymphatic invasion as well as intratumoral and peritumoral lymphatic vascular density were positively correlated with lymph node metastasis.

Conclusions

Our results suggest that iNOS-mediated NO formation plays an important role in gastric carcinogenesis, tumor lymphangiogenesis, and the development of lymphatic metastases. Inhibition of the NO pathway may be an alternative treatment of gastric carcinomas.

Virtual slides

The virtual slides for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1713572940104388.

Macrophage-tumor cell interactions regulate the function of nitric oxide

Tumor cell-macrophage interactions change as the tumor progresses, and the generation of nitric oxide (NO) by the inducible nitric oxide synthase (iNOS) plays a major role in this interplay. In early stages, macrophages employ their killing mechanisms, particularly the generation of high concentrations of NO and its derivative reactive nitrogen species (RNS) to initiate tumor cell apoptosis and destroy emerging transformed cells. If the tumor escapes the immune system and grows, macrophages that infiltrate it are reprogramed in situ by the tumor microenvironment. Low oxygen tensions (hypoxia) and immunosuppressive cytokines inhibit iNOS activity and lead to production of low amounts of NO/RNS, which are pro-angiogenic and support tumor growth and metastasis by inducing growth factors (e.g., VEGF) and matrix metalloproteinases (MMPs). We review here the different roles of NO/RNS in tumor progression and inhibition, and the mechanisms that regulate iNOS expression and NO production, highlighting the role of different subtypes of macrophages and the microenvironment. We finally claim that some tumor cells may become resistant to macrophage-induced death by increasing their expression of microRNA-146a (miR-146a), which leads to inhibition of iNOS translation. This implies that some cooperation between tumor cells and macrophages is required to induce tumor cell death, and that tumor cells may control their fate. Thus, in order to induce susceptibility of tumors cells to macrophage-induced death, we suggest a new therapeutic approach that couples manipulation of miR-146a levels in tumors with macrophage therapy, which relies on ex vivo stimulation of macrophages and their re-introduction to tumors.

A randomized phase II study of irinotecan plus cisplatin versus irinotecan plus capecitabine with or without isosorbide-5-mononitrate in advanced non-small-cell lung cancer

BACKGROUND

We investigated the efficacy of irinotecan/cisplatin (IP) versus irinotecan/capecitabine (IX) with or without isosorbide-5-mononitrate (ISMN) in chemo-naïve advanced non-small-cell lung cancer.

PATIENTS AND METHODS

Initially, 74 patients were randomly assigned to either IP or IX. Given the potential benefits of ISMN on chemotherapy, the protocol was amended during the study. Subsequently, 72 patients were randomly assigned to either IP + ISMN or IX + ISMN. Patients were treated with predefined second-line therapies (docetaxel/capecitabine for IP or IP + ISMN, docetaxel/cisplatin for IX or IX + ISMN) when disease progressed.

RESULTS

A total of 146 received treatment. Response rate (RR), median progression-free survival (PFS) and overall survival (OS) were 49%, 5.5 months, 14.5 months in IP; 33%, 3.3 months, 13.0 months in IP + ISMN; 30%, 4.3 months, 16.1 months in IX; and 25%, 3.4 months, 13.6 months in IX + ISMN, respectively. While IP arm showed a trend toward higher RR and longer PFS than IX arm, IX arm showed a trend toward longer OS than IP arm. No significant differences were observed between IP + ISMN and IX + ISMN.

CONCLUSION

IP showed better RR and PFS but no OS benefit when compared with IX. The addition of ISMN to IP or IX chemotherapy did not seem to improve the treatment outcome.

[Construction of A eukaryotic expression vector carrying the iNOS gene and its effect on A549 lung cancer cells]

背景与目的

iNOS与NO介导的抗肿瘤效应有关。本研究旨在构建pVAX-iNOS载体并转染A549肺癌细胞，检测其基因的表达并初步探讨iNOS基因表达增高后对A549肺癌细胞的抗肿瘤作用。

方法

应用RT-PCR方法扩增人iNOS编码序列的CDS片段，构建pVAX-iNOS载体后转染肺癌A549细胞，通过RT-PCR和Western blot方法检测目的基因的表达；采用MTT法、Hoechst 3235染色和划痕实验分别检测iNOS高表达在体外对肺癌A549细胞增殖、凋亡和迁移作用的影响。

结果

真核表达质粒载体pVAX-iNOS构建成功，iNOS蛋白在转染后的A549细胞中表达升高。pVAX-iNOS转染A549肺癌细胞后能明显诱导细胞发生凋亡并抑制肿瘤细胞的生长和迁移。

结论

本研究成功构建pVAX-iNOS真核表达质粒，高表达iNOS能明显抑制A549细胞的增殖、迁移并促进细胞发生凋亡。本研究有望为临床治疗肺癌提供一个新的有效策略。

S-nitrosoglutathione reductase in human lung cancer

S-Nitrosoglutathione (GSNO) reductase regulates cell signaling pathways relevant to asthma and protects cells from nitrosative stress. Recent evidence suggests that this enzyme may prevent human hepatocellular carcinoma arising in the setting of chronic hepatitis. We hypothesized that GSNO reductase may also protect the lung against potentially carcinogenic reactions associated with nitrosative stress. We report that wild-type Ras is S-nitrosylated and activated by nitrosative stress and that it is denitrosylated by GSNO reductase. In human lung cancer, the activity and expression of GSNO reductase are decreased. Further, the distribution of the enzyme (including its colocalization with wild-type Ras) is abnormal. We conclude that decreased activity of GSNO reductase could leave the human lung vulnerable to the oncogenic effects of nitrosative stress, as is the case in the liver. This potential should be considered when developing therapies that inhibit pulmonary GSNO reductase to treat asthma and other conditions.

Nitrosothiol Signaling in Anoikis Resistance and Cancer Metastasis

Nitric oxide (NO) has been widely recognized as an important cell-signaling molecule that regulates various physiological and pathological processes. S-nitrosylation, or covalent attachment of NO to protein sulfhydryl groups, is a key mechanism by which NO regulates protein functions and cellular processes. In this article we discuss the various roles of NO and protein nitrosylation in cancer development, with a focus on cell invasion and anoikis resistance, both of which are key determinants of cancer metastasis. We specially address some of the mechanisms by which NO-mediated S-nitrosylation modulates substrates that have putative effects on key steps of metastasis. We propose that nitrosothiol signaling is a key regulatory mechanism common to several pathways involved in cancer progression and metastasis, and identifying such a mechanism will improve our understanding of the disease process and aid in the development of novel anticancer therapeutics.

Nitric oxide and protein phosphatase 2A provide novel therapeutic opportunities in ER-negative breast cancer

Basal-like breast cancer is an aggressive disease with limited therapeutic options because these tumors frequently express the 'triple-negative' phenotype. We have recently reported that inducible nitric oxide synthase (NOS2) is a strong predictor of survival in patients with estrogen receptor negative [ER(-)] breast cancer, and that NOS2 expression is correlated with a basal-like phenotype. Recent reports also describe the pro-tumor effects of NO in breast and many other types of cancer. NO promotes cancer progression by activating several oncogenic signaling pathways such as extracellular signal-regulated kinases (ERK)-1/2, phosphoinositide 3-kinases (PI3K)/Akt, and c-Myc. Protein phosphatase 2A (PP2A) is a tumor suppressor that negatively regulates the same cancer-related signaling pathways that are activated by NO. PP2A activity is suppressed in tumor cells, but potential pharmacological agents have recently been described to increase PP2A activity in ER(-) breast cancer cells. We examine here the various functions of NO and PP2A in breast cancer and propose a novel mechanism by which activation of PP2A antagonizes NO signaling that promotes ER(-) breast cancer.

The tissue microlocalisation and cellular expression of CD163, VEGF, HLA-DR, iNOS, and MRP 8/14 is correlated to clinical outcome in NSCLC

Background

We have previously investigated the microlocalisation of M1 and M2 macrophages in NSCLC. This study investigated the non-macrophage (NM) expression of proteins associated with M1 and M2 macrophages in NSCLC.

Methods

Using immunohistochemistry, CD68⁺ macrophages and proteins associated with either a cytotoxic M1 phenotype (HLA-DR, iNOS, and MRP 8/14), or a non-cytotoxic M2 phenotype (CD163 and VEGF) were identified. NM expression of the markers was analysed in the islets and stroma of surgically resected tumours from 20 patients with extended survival (ES) (median 92.7 months) and 20 patients with poor survival (PS) (median 7.7 months).

Results

The NM expression of NM-HLA-DR (p<0.001), NM-iNOS (p = 0.02) and NM-MRP 8/14 (p = 0.02) was increased in ES compared to PS patients in the tumour islets. The tumour islet expression of NM-VEGF, was decreased in ES compared to PS patients (p<0.001). There was more NM-CD163 expression (p = 0.04) but less NM-iNOS (p = 0.002) and MRP 8/14 (p = 0.01) expression in the stroma of ES patients compared with PS patients. The 5-year survival for patients with above and below median NM expression of the markers in the islets was 74.9% versus 4.7% (NM-HLA-DR p<0.001), 65.0% versus 14.6% (NM-iNOS p = 0.003), and 54.3% versus 22.2% (NM-MRP 8/14 p = 0.04), as opposed to 34.1% versus 44.4% (NM-CD163 p = 0.41) and 19.4% versus 59.0% (NM-VEGF p = 0.001).

Conclusions

Cell proteins associated with M1 and M2 macrophages are also expressed by other cell types in the tumour islets and stroma of patients with NSCLC. Their tissue and cellular microlocalisation is associated with important differences in clinical outcome.

Inducible nitric oxide synthase expression and its prognostic significance in colorectal cancer

Nitric oxide synthases (NOS) are expressed in colorectal cancer. The aim of this study was to examine the inducible NOS (iNOS) expression in colorectal cancer and to investigate its prognostic relevance. Tissue sections of primary tumors from 132 patients undergoing curative resection for colorectal cancer were immunohistochemically examined for iNOS expression. The expression pattern of iNOS was correlated with various clinicopathological characteristics and survival. iNOS immunoreactivity was observed in the cytoplasm of tumor epithelial cells in 60 patients (45.5%) and positively correlated with lymph node involvement (p = 0.019). No significant correlation was found between iNOS expression and various clinicopathological characteristics, including age, gender, tumor location, tumor size, tumor grade, T stage, and Union International Contra la Cancrum (UICC) stage. Survival analysis showed a significant correlation between iNOS-positive tumors and poor disease-specific survival (p < 0.0001), with independent prognostic significance in multivariate analysis (HR = 4.42; p < 0.0001). Patients with stage II disease and iNOS-positive tumors had significantly worse disease-specific survival than those with iNOS-negative tumors (p < 0.0001). In addition, patients with stage III disease and iNOS-positive tumors had significantly worse disease-specific survival than those with iNOS-negative tumors (p = 0.001). The ability of iNOS to predict outcome in colorectal cancer patients may be independent of other known prognostic factors, providing a new molecular marker with significant potential for clinical utility.

Targeting nitric oxide for cancer therapy

A blueprint for the ideal anticancer molecule would include most of the properties of nitric oxide (NO•), but the ability to exploit these characteristics in a therapeutic setting requires a detailed understanding of the biology and biochemistry of the molecule. These properties include the ability of NO• to affect tumour angiogenesis, metastasis, blood flow and immuno surveillance. Furthermore NO• also has the potential to enhance both radio- and chemotherapy. However, all of these strategies are dependent on achieving appropriate levels of NO•, since endogenous levels of NO• appear to have a clear role in tumour progression. This review aims to summarize the role of NO• in cancer with particular emphasis on how the properties of NO• can be exploited for therapy.

Apoptosis-inducing high (.)NO concentrations are not sustained either in nascent or in developed cancers

Nitric oxide ((.)NO) induces apoptosis at high concentrations by S-nitrosating proteins such as glyceraldehyde-3-phosphate dehydrogenase. This literature analysis revealed that failure to sustain high (.)NO concentrations is common to all cancers. In cervical, gastric, colorectal, breast, and lung cancer, the cause of this failure is the inadequate expression of inducible nitric oxide synthase (iNOS), resulting from the inhibition of iNOS expression by TGF-beta1 at the mRNA level. In bladder, renal, and prostate cancer, the reason for the insufficient (.)NO levels is the depletion of arginine, resulting from arginase overexpression. Arginase competes with iNOS for arginine, catalyzing its hydrolysis to ornithine and urea. In gliomas and ovarian sarcomas, low (.)NO levels are caused by inhibition of iNOS by N-chlorotaurine, produced by infiltrating neutrophils. Stimulated neutrophils express myeloperoxidase, catalyzing H2O2 oxidation of Cl- to HOCl, which N-chlorinates taurine at its concentration of 19 mM in neutrophils. In squamous cell carcinomas of the skin, ovarian cancers, lymphomas, Hodgkin's disease, and breast cancers, low (.)NO concentrations arise from the inhibition of iNOS by N-bromotaurine, produced by eosinophil-peroxidase-expressing infiltrating eosinophils. Eosinophil peroxidase catalyzes the H2O2 oxidation of Br- to HOBr, which N-brominates taurine to N-bromotaurine at its concentration of 15 mM in eosinophils. In microvascularized tumors, the (.)NO concentration is further depleted; (.)NO is rapidly consumed by red blood cells (RBCs) through S-nitrosation of RBC glutathione and hemoglobin, and by oxidation to nitrate by RBC oxyhemoglobin. Angiogenesis-inhibiting antibodies are currently used to treat cancers; their mode of action is not, as previously thought, reduction of the tumor O2 or nutrient supply. They actually decrease the loss of (.)NO to RBCs.

Increased expression of inducible nitric oxide synthase (iNOS) in N-nitrosobis(2-oxopropyl)amine-induced hamster pancreatic carcinogenesis and prevention of cancer development by ONO-1714, an iNOS inhibitor

Elevated protein expression of inducible nitric oxide synthase (iNOS) has been observed in human pancreatic cancers and therefore, iNOS may play important roles in pancreatic carcinogenesis. This was examined in the present study, using an experimental model with N-nitrosobis(2-oxopropyl)amine (BOP)-treated hamsters. Reverse transcription-polymerase chain reaction analysis demonstrated iNOS expression in a hamster pancreatic cancer cell line as well as in human pancreatic cancer cell lines. Immunohistochemical analysis revealed increased expression of iNOS protein in atypical hyperplasia and ductal adenocarcinomas of the pancreas in BOP-treated hamsters. In addition, iNOS expression was also observed in macrophages and islet cells in pancreatic tissue surrounding tumors. In order to assess the role of iNOS expression in carcinogenesis in the pancreas, the effects of ONO-1714 [(1S, 5S, 6R, 7R)-7-chloro-3-imino-5-methyl-2-azabicyclo[4.1.0]heptane], an iNOS inhibitor, on hamster pancreatic ductal carcinogenesis were investigated. Female Syrian golden hamsters were treated with BOP at 10 mg/kg body wt, four times for 1 week, and 1 week after the last carcinogen treatment, ONO-1714 was administered at doses of 100 and 200 p.p.m. in the diet for 15 weeks. The incidences and multiplicities of atypical hyperplasia and invasive adenocarcinoma and total adenocarcinomas (non-invasive and invasive adenocarcinomas) in the pancreas were significantly lowered by treatment with 200 p.p.m. ONO-1714. Treatment with 100 p.p.m. ONO-1714 also significantly decreased the multiplicities of invasive and total adenocarcinomas. Moreover, treatment with 200 p.p.m. ONO-1714 reduced the number of BOP-induced cholangiocellular tumors. These results suggest that iNOS plays roles in promoting pancreatic carcinogenesis in both early and late stages in hamsters.

Increased inducible nitric oxide synthase in lung carcinoma of smokers

BACKGROUND

Cigarette smoking is well known to play an important role in the development of lung cancer. Inducible nitric oxide synthase (iNOS) can either promote or inhibit cell proliferation and growth, which makes its role in the development of malignant tumors controversial. The relation between cigarette smoking and iNOS in human lung cancer is unknown.

METHODS

The study examined the levels of iNOS/NO in nonsmall-cell lung cancer (NSCLC) tissues of smokers and nonsmokers and in NSCLC cells (NCI-H23) treated by 4-(N-Methyl-N-nitrosamino)-1-(3-pyridyl)-1-butanone (NNK), a potent tobacco-specific carcinogen.

RESULTS

The level of iNOS/NO was significantly higher in lung cancer tissues of smokers than that of nonsmokers. Unlike iNOS/NO, the activity of caspase-3 was reduced in the former compared with the latter. The expression of the cleaved caspase-3 was deceased in NCI-H23 cells treated with S-Nitroso-N-acetylpenicillamine (SNAP), an NO donor, whereas treatment with NG-methyl-L-arginine (NMA), an NO inhibitor, caused an increase in cleaved caspase-3. Consistent with the change in caspase-3, SNAP treatment inhibited cell death induced by UCN01, a potent cell death-inducer. NMA treatment greatly enhanced the sensitivity of the cells to UCN01. Further, the cells treated by NNK showed an increase in iNOS protein, accompanied by an elevation of cell proliferation.

CONCLUSIONS

The study demonstrates that cigarette smoking promotes the level of iNOS/NO but suppresses the activity of caspase-3, which may lead to the proliferation and growth of lung cancer cells.

Higher serum nitrate levels are associated with poor survival in lung cancer patients

OBJECTIVES

Angiogenic factors induce tumour growth and angiogenesis which leads to tumour metastasis and a poor survival rate. This study aimed to assess the possible roles of nitric oxide (NO) and vascular endothelial growth factor-A (VEGF-A) in the overall survival of patients with late stage lung cancer.

DESIGN AND METHODS

The study was carried out with primary lung carcinoma patients (n=31) and healthy controls (n=15). Pre- and post-cisplatin-based chemotherapy serum nitrite/nitrate levels were measured as nitrite after enzymatic conversion followed by Griess reaction and serum VEGF-A analysis was performed using ELISA. After patient follow-up, survival rates were calculated by using the Kaplan-Meier method [Dudek et al. Cancer Invest 2005; 23(3):193-200].

RESULTS

The serum nitrite/nitrate and VEGF-A levels of lung cancer patients and the control group were 93.7+/-48.9 and 63.7+/-32.2 microM (p=0.018), and 620+/-491 and 255+/-157 pg/mL (p=0.001), respectively. High nitrite/nitrate (>67.2 microM) concentration had statistically significant effects on overall survival (Cox analysis, p=0.026). The overall survival of the lung cancer patients with higher serum nitrate concentrations was significantly less than the ones with lower serum nitrite/nitrate (Kaplan-Meier survival functions test, log rank significance=0.0007).

CONCLUSION

Our results suggest that having a high serum nitrite/nitrate concentration is a strong indicator of poor survival for late stage lung cancer patients. However, this conclusion deserves to be elucidated further by using a larger sample size.

Nitric Oxide Regulates Cell Sensitivity to Cisplatin-Induced Apoptosis throughS-Nitrosylation and Inhibition of Bcl-2 Ubiquitination

Cisplatin is a potent cytotoxic agent commonly used for the treatment of solid tumors. However, tumor cell-acquired resistance to cisplatin-induced apoptosis is a major limitation for efficient therapy, as frequently observed in human lung cancer. Nitric oxide (NO) is a key regulator of apoptosis, but its role in cisplatin-induced cell death and the underlying mechanism are largely unknown. Previous studies indicate increased NO synthase activity and elevated NO production in lung carcinomas, which correlate with the incidence of chemotherapeutic resistance. Here, we show that NO impairs the apoptotic function of cells and increases their resistance to cisplatin-induced cell death in human lung carcinoma H-460 cells. The NO donors sodium nitroprusside and dipropylenetriamine NONOate were able to inhibit cisplatin-induced cell death, whereas the NO inhibitors aminoguanidine and 2-(4-carboxyphenyl)-4,4,5,5-tetra-methylimidazoline-1-oxyl-3-oxide had opposite effect. Cisplatin resistance in H-460 cells is mediated by Bcl-2, and NO up-regulates its expression by preventing the degradation of Bcl-2 via ubiquitin-proteasome pathway. Cisplatin-induced generation of reactive oxygen species causes dephosphorylation and degradation of Bcl-2. In contrast, generation of NO has no effect on Bcl-2 phosphorylation but induces S-nitrosylation of the protein, which inhibits its ubiquitination and subsequent proteasomal degradation. These findings indicate a novel pathway for NO regulation of Bcl-2, which provides a key mechanism for cisplatin resistance and its potential modulation for improved cancer chemotherapy.

Nitric oxide synthases are associated with bronchial dysplasia

Recent studies suggest that reactive oxygen (ROS) and nitrogen species (RNS) are highly associated with the pathogenesis of cigarette smoke related lung diseases but their role in the malignant conversion of bronchial epithelium is unclear. The immunohistochemical expression of inducible, endothelial and neuronal nitric oxide synthases (iNOS, eNOS and nNOS) and nitrotyrosine as a biomarker of oxidative/nitrosative stress was evaluated in 79 cases including 13 non-smokers, 20 smokers without chronic obstructive pulmonary disease (COPD), 22 with COPD and 24 with metaplasia-dysplasia-sequence of the bronchial epithelium. Normal lung of non-smokers was mainly negative for nitrotyrosine, while it was higher in the alveolar macrophages of cigarette smokers and COPD than in non-smokers (p=0.025, p<0.001), and in the alveolar epithelium of smokers and COPD than in non-smokers (p=0.049). There were no major differences in the nitrotyrosine immunoreactivity between the metaplastic/dysplastic lesions and bronchial epithelium of cigarette smokers. Inducible NOS and nNOS were mainly non-detectable or weak in the normal looking bronchial epithelium of smokers and COPD, whereas metaplasia and dysplasia showed positivity for iNOS (22/24) and nNOS (14/24) in the majority of cases. Strong immunoreactivity for iNOS and nNOS was also found more often in dysplastic than metaplastic (p=0.011 and p=0.049, respectively) specimens. Thus, smoking can cause protein nitration also in normal lung. Prominent iNOS and nNOS immunoreactivity in the metaplasia-dysplasia-lesions suggests a divergent role of NOSs in lung carcinogenesis.

Significance of inducible nitric oxide synthase expression in benign and malignant breast epithelium: an immunohistochemical study of 151 cases

The role of calcium independent inducible nitric oxide synthase (iNOS) in breast carcinoma is controversial, and the implications of iNOS expression on prognosis are not known. In this study, we aimed to investigate the significance of immunohistochemical iNOS expression in 100 invasive ductal carcinomas. In addition, 11 normal breast tissues, 20 cases of usual ductal hyperplasias (UDHs) and 20 fibroadenomas were included. We found that 78% of malignant and 75% of benign cases showed iNOS immunoreactivity. However, the intensity and the quantity of iNOS expression were significantly higher in the cancer group when compared with benign breasts (P<0.001), suggesting a role of iNOS in breast carcinogenesis. We were unable to show a correlation between iNOS expression and tumor grade, axillary lymph node status, and estrogen receptor expression. In 50 axilla negative cases having 5--12 years follow-up, disease free survival (DFS) rate was significantly lower in cases showing strong iNOS expression (P=0.05). As strong iNOS expression was correlated with short DFS, we concluded that further studies would be necessary to elucidate if iNOS expression might be a useful prognostic marker in breast carcinoma, especially in the axilla negative group.

Differential requirement of signal pathways for benzo[ a ]pyrene (B[ a ]P)-induced nitric oxide synthase (iNOS) in rat esophageal epithelial cells

Overexpression of inducible nitric oxide synthase (iNOS) has been reported in several human cancers, including esophageal squamous cell carcinoma (SCC). Benzo[a]pyrene (B[a]P), a polycyclic hydrocarbon carcinogen found in tobacco smoke and in the environment, induces cancer in multiple organ sites in animals and may be a causative agent for certain human cancers, such as esophageal cancer. In the present study, the effects of B[a]P on the induction of iNOS and the signaling pathways that lead to the induction were investigated in cultured rat esophageal epithelial (RE-149) cells. Treatment of RE-149 cells with B[a]P led to a marked increase in the expression of iNOS. The induction of iNOS by B[a]P was found to occur through an extracellular signal-regulated protein kinases (ERKs)-dependent pathway, since inhibition of ERKs by either pretreatment of RE-149 cells with PD98059, an inhibitor of ERKs upstream kinase MEK1/2, or overexpression of DN-ERK2, blocked the induction of iNOS by B[a]P. Furthermore, impairing nuclear factor-kappaB (NFkappaB) activation by either NEMO-BDBP, an NFkappaB specific inhibitor, or overexpression of DN-IkappaBalpha or IKK-KM markedly inhibited the expression of B[a]P-induced iNOS, suggesting that the NFkappaB pathway is also required for the induction of iNOS by B[a]P. In addition, treatment of RE-149 cells with either SB202190, a p38 kinase inhibitor, or c-JunN-terminal kinase inhibitor II, resulted in an increased induction of iNOS. Pretreatment of RE-149 cells with wortmannin, a PI-3K inhibitor, or with rapamycin, an mTOR/p70S6K pathway inhibitor, had no effect on the expression of iNOS. These results suggest that B[a]P initiates the signaling pathways leading to the induction of iNOS in cultured rat esophageal epithelial cells. In view of the potential role of iNOS in the development of esophageal SCC in humans, we speculate that the induction of iNOS by B[a]P may be one mechanism by which B[a]P could produce carcinogenic effects in the human esophagus.

The role of early expression of inducible nitric oxide synthase in human breast cancer

Nitric oxide synthases are expressed in breast cancer. To elucidate the clinical role of the inducible NOS (i-NOS) in human breast cancer, 161 primary breast cancer tissues were stained immunohistochemically. Staining patterns for i-NOS were correlated with classical prognostic factors such as lymph node status, age, hormonal receptor status, tumour size and tumour differentiation. With classical prognostic factors such as lymph node status, age, hormonal receptor status, tumour size and tumour differentiation. Patients survival was also analysed. Sixty-one percent of the tumours stained positively for i-NOS. Detection of i-NOS was positively correlated with increasing tumour size and decreasing tumour differentiation (P=0.018 and P=0.039, respectively). However, in the 50 year age group, i-NOS staining also correlated with lymph node status. Patients with i-NOS-positive breast carcinomas had a significantly worse overall survival rate versus those with negative stains (5-year survival rate 84.8% versus 67.1%; P=0.049; log-rank test). To date, this is the largest analysis of i-NOS expression in breast cancer patients and the only study to assess survival.