Nicotine-derived Nitrosamine Ketone Research Articles

Suppressing the activation of protein kinase A as a DNA damage-independent mechanistic lead for dihydromethysticin prophylaxis of NNK-induced lung carcinogenesis.

Our earlier work demonstrated varying potency of dihydromethysticin (DHM) as the active kava phytochemical for prophylaxis of tobacco carcinogen nicotine-derived nitrosamine ketone (NNK)-induced mouse lung carcinogenesis. Efficacy was dependent on timing of DHM gavage ahead of NNK insult. In addition to DNA adducts in the lung tissues mitigated by DHM in a time-dependent manner, our in vivo data strongly implicated the existence of DNA damage-independent mechanism(s) in NNK-induced lung carcinogenesis targeted by DHM to fully exert its anti-initiation efficacy. In the present work, RNA seq transcriptomic profiling of NNK-exposed (2 h) lung tissues with/without a DHM (8 h) pretreatment revealed a snap shot of canonical acute phase tissue damage and stress response signaling pathways as well as an activation of protein kinase A (PKA) pathway induced by NNK and the restraining effects of DHM. The activation of the PKA pathway by NNK active metabolite 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) at a concentration incapable of promoting DNA adduct was confirmed in a lung cancer cell culture model, potentially through NNAL binding to and activation of the β-adrenergic receptor. Our in vitro and in vivo data overall support the hypothesis that DHM suppresses PKA activation as a key DNA damage-independent mechanistic lead, contributing to its effective prophylaxis of NNK-induced lung carcinogenesis. Systems biology approaches with a detailed temporal dissection of timing of DHM intake versus NNK exposure are warranted to fill the knowledge gaps concerning the DNA damage-driven mechanisms and DNA damage-independent mechanisms to optimize the implementation strategy for DHM to achieve maximal lung cancer chemoprevention.

In vivo Structure-Activity Relationship of Dihydromethysticin in Reducing Nicotine-Derived Nitrosamine Ketone (NNK)-Induced Lung DNA Damage against Lung Carcinogenesis in A/J Mice.

Lung cancer is the leading cause of cancer-related deaths and chemoprevention should be developed. We recently identified dihydromethysticin (DHM) as a promising candidate to prevent NNK-induced lung tumorigenesis. To probe its mechanisms and facilitate its future translation, we investigated the structure-activity relationship of DHM on NNK-induced DNA damage in A/J mice. Twenty DHM analogs were designed and synthesized. Their activity in reducing NNK-induced DNA damage in the target lung tissues was evaluated. The unnatural enantiomer of DHM was identified to be more potent than the natural enantiomer. The methylenedioxy functional moiety did not tolerate modifications while the other functional groups (the lactone ring and the ethyl linker) accommodated various modifications. Importantly, analogs of high structural similarity to DHM with distinct efficacy in reducing NNK-induced DNA damage have been identified. They will serve as chemical probes to elucidate the mechanisms of DHM in blocking NNK-induced lung carcinogenesis.

Effect of Conjugated Linoleic Acid (CLA) Supplementation on Expression of B-Cell Lymphoma-2 (Bcl-2) in the Bladder Epithelium of Wistar (Rattus norvegicus) Rats Exposed to Cigarette Smoke.

Bladder carcinoma is the 10th most common cancer in the world with an incidence about 3% of all cancers. The risk factor for smoking is found in 81% of all cases of bladder carcinoma. One of the protein groups associated with bladder urothelial carcinoma is B-Cell Lymphoma-2 (Bcl-2). Nicotine-derived nitrosamine ketone (NNK) contained in cigarette smoke would increase the proliferation of cancer cells through increased the expression of Bcl-2. The expression of Bcl-2 could be suppressed in the presence of Conjugated Linoleic Acid (CLA), a polyunsaturated fatty acid that has role in reducing the risk of cancer development which is reported in several studies, and then stimulate cell apoptosis. To determine the effect of CLA supplementation on Bcl-2 expression in the bladder of rats which is exposed to cigarette smoke. The study is an experimental study with true experimental posttest only control group design on Wistar rats. Sample was divided into 2 case groups: 0.5% of diet (125 mg) CLA supplementation in group A, 1% of diet (250 mg) CLA in group B; and 2 control groups: group without CLA supplementation (group C) as positive control and without cigarette smoke exposure (group D) as negative control. The study takes 60 days of exposure and then Bcl-2 expression on bladder epithelial was evaluated by immunohistochemistry staining. The results descriptively showed that rats in group C has an average Bcl-2 expression of 25.8±7.33%, while rats in group D has an average Bcl-2 expression 14.1±7.73% which means cigarette smoke exposure has been shown to increase the expression of Bcl-2 by 45.35% (p=0.019) in the bladder mucosa of experimental animals. Group B obtained an average Bcl-2 expression was 14.2±9.6% and has a significant difference when compared to group C, it shows that the addition of 1% CLA would reduce the expression of Bcl-2 by 44.96% (p=0.032). However, for group A, group with 0.5% diet of CLA supplementation did not showed decrease of Bcl-2 expression when compared to the group C (p=0.37). Conjugated Linoleic Acid (CLA) supplementation 1% of diet can reduce Bcl-2 expression in bladder epithelium of wistar rats (Rattus norvegicus) exposed to cigarette smoke.

Lung Tumor Growth Promotion by Tobacco-Specific Nitrosamines Involves the β2-Adrenergic Receptors-Dependent Stimulation of Mitochondrial REDOX Signaling.

Aims: Lung cancer is the leading cause of cancer death worldwide, and tobacco smoking is a recognized major risk factor for lung tumor development. We analyzed the effect of tobacco-specific nitrosamines (TSNAs) on human lung adenocarcinoma metabolic reprogramming, an emergent hallmark of carcinogenesis. Results: A series of in vitro and in vivo bioenergetic, proteomic, metabolomic, and tumor biology studies were performed to analyze changes in lung cancer cell metabolism and the consequences for hallmarks of cancer, including tumor growth, cancer cell invasion, and redox signaling. The findings revealed that nicotine-derived nitrosamine ketone (NNK) stimulates mitochondrial function and promotes lung tumor growth in vivo. These malignant properties were acquired from the induction of mitochondrial biogenesis induced by the upregulation and activation of the beta-2 adrenergic receptors (β2-AR)-cholinergic receptor nicotinic alpha 7 subunit (CHRNAα7)-dependent nitrosamine canonical signaling pathway. The observed NNK metabolic effects were mediated by TFAM overexpression and revealed a key role for mitochondrial reactive oxygen species and Annexin A1 in tumor growth promotion. Conversely, ectopic expression of the mitochondrial antioxidant enzyme manganese superoxide dismutase rescued the reprogramming and malignant metabolic effects of exposure to NNK and overexpression of TFAM, underlining the link between NNK and mitochondrial redox signaling in lung cancer. Innovation: Our findings describe the metabolic changes caused by NNK in a mechanistic framework for understanding how cigarette smoking causes lung cancer. Conclusion: Mitochondria play a role in the promotion of lung cancer induced by tobacco-specific nitrosamines. Antioxid. Redox Signal. 36, 525-549.

Preliminary evaluation of anticancer efficacy of pioglitazone combined with celecoxib for the treatment of non-small cell lung cancer.

Among the lung cancer types, non-small cell lung cancer (NSCLC) is prominent and less responsive to chemotherapy. The current chemotherapeutics for NSCLC are associated with several dose-limiting side effects like bone-marrow suppression, neurotoxicity, nephrotoxicity, and ototoxicity, etc. which are causing non-compliance in patients. Many tumors, including breasts, lung, ovarian, etc. overexpress PPAR-γ receptors and COX-2 enzymes, which play a crucial role in tumor progression, angiogenesis, and metastasis. Lack of PPAR-γ activation and overproduction of prostaglandins, result in uncontrolled activation of Ras/Raf/Mek ultimately, NF-κB mediated tumor proliferation. This study aimed to investigate the anti-cancer potential of PPAR-γ agonist Pioglitazone combined with COX-2 inhibitor Celelcoxib in NSCLC. Sixty adult Balb/C male mice were classified into sham control, disease control, and treatment groups. Mice were treated with Nicotine-derived nitrosamine ketone (NNK) (10mg/kg), pioglitazone (10 & 20mg/kg) and celecoxib (25 & 50mg/kg). Weekly body weight, food intake, mean survival time & % increased life span were determined. Tumor weight and histopathological analysis were performed at the end of the study. The significant tumor reducing potential of pioglitazone combined with celecoxib was observed (p < 0.05). The treatment groups (treated with pioglitazone and celecoxib) showed a remarkable decrease in lung tumor weight, improved life span and mean survival time (p < 0.05). Histopathological studies confirm that treatment groups (treated with pioglitazone and celecoxib) reframed the lung architecture compared to disease control. Preliminary results revealed that pioglitazone adjunacy with celecoxib may be an effective chemo-preventive agent against NNK induce NSCLC.

Thirdhand smoke exposure: Differences in smoke exposure indices and cultural norms between hotels and motels in South Korea

The legal regulations and cultural environment for smoking bans in hotels and motels in South Korea differ depending on the type of accommodation. The aim of this study was to assess the thirdhand smoke exposure for hotel and motel guests staying at accommodations who are expected to be relatively vulnerable to thirdhand smoke. Biomarkers for 28 participants were assessed before and after lodging at a hotel or motel for approximately 14 h. Hotel participants had statistically decreased urinary cotinine concentrations after their stay, whereas motel participants experienced increased concentrations. The concentration of nicotine-derived nitrosamine ketone in dust in hotels was lower than that in motels, and the higher dust nicotine-derived nitrosamine ketone concentration in motels had more effect on an increase in urinary cotinine concentration. Both hotels and motels legally allowed smoking in guest rooms. However, the study participants in hotels were less exposed to thirdhand smoke than those in motels.

SMOKING CARCINOGENS AND LUNG CANCER – A REVIEW

Smoking ambiguity contributes to a certain revelation regarding the process by which cancer is induced. In the laboratory, carcinogens induce clear lung tumor to lung cancer induction. For instance, carcinogenic chemicals, namely, 4(methyl nitrosomine)-1-(3-pyridyl)-1-butanol, and nitrosonornicotine (NNN) cause tumor malignancy. It is evident from the mechanistic studies that the carcinogens have a stronger tendency to mutate the genes like suppresser gene, a gene that encodes the receptor of the cell surface to the nucleus, thus, giving way to the proliferation of mutation leading to neoplastic cells. In this analysis article, we have discussed molecular mechanics that can cause cancer by nitrosamines such as nicotine-derived nitrosamine ketone and NNN regarding a variety of significant cigarette combustion carcinogens and the effort to introduce a different dimensional approach to the prevention of cancer, by understanding the perspective of various treatments.

Inhibitory effects of Nigella sativa nano-capsule on the expression of cyclin D1 in the lungs of wistar rats exposed to nicotine-derived nitrosamine ketone

Inhibitory effects of Nigella sativa nano-capsule on the expression of cyclin D1 in the lungs of wistar rats exposed to nicotine-derived nitrosamine ketone

Low carbohydrate diets containing soy protein and fish oil slow the growth of established NNK-induced lung tumors.

We recently found that a diet composed of 15% of total calories as carbohydrate (CHO), primarily as amylose, 35% soy protein and 50% fat, primarily as fish oil (FO) (15%Amylose/Soy/FO) was highly effective at preventing lung nodule formation in a nicotine-derived nitrosamine ketone (NNK)-induced lung cancer model. We asked herein whether adopting such a diet once cancers are established might also be beneficial. To test this, NNK-induced lung nodules were established in mice on a Western diet and the mice were then either kept on a Western diet or switched to various low CHO diets. Since we previously found that sedentary mice develop more lung nodules than active mice, we also compared the effect of exercise in this cancer progression model. We found that switching to a 15%Amylose/Soy/FO diet reduced lung nodules and slowed tumor growth with both 'active' and 'sedentary' mice. Ki67, cleaved caspase 3 and Terminal Deoxynucleotidyl Transferase-Mediated dUTP Nick End Labeling assays suggested that the efficacy of the 15%Amylose/Soy/FO in lowering tumor nodule count and size was not due to a reduction in tumor cell proliferation, but to an increase in apoptosis. The 15%Amylose/Soy/FO diet also significantly lowered liver fatty acid synthase and 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 expression, pointing to a global metabolic switch from glycolysis to fatty acid oxidation. Mice fed the 15%Amylose/Soy/FO diet also had significantly reduced plasma levels of interleukin (IL)-1β, IL-6 and tumor necrosis factor α. These results suggest that the 15%Amylose/Soy/FO diet may slow tumor growth by suppressing proinflammatory cytokines, inducing a metabolic switch away from glycolysis and inducing apoptosis in tumors.

TIPE2 Induced the Proliferation, Survival, and Migration of Lung Cancer Cells Through Modulation of Akt/mTOR/NF-κB Signaling Cascade.

Lung cancer represents the most common cause of cancer deaths in the world, constituting around 11.6% of all new cancer cases and 18.4% of cancer-related deaths. The propensity for early spread, lack of suitable biomarkers for early diagnosis, as well as prognosis and ineffective existing therapies, contribute to the poor survival rate of lung cancer. Therefore, there is an urgent need to develop novel biomarkers for early diagnosis and prognosis which in turn can facilitate newer therapeutic avenues for the management of this aggressive neoplasm. TIPE2 (tumor necrosis factor-α-induced protein 8-like 2), a recently identified cytoplasmic protein, possesses enormous potential in this regard. Immunohistochemical analysis showed that TIPE2 was significantly upregulated in different stages and grades of lung cancer tissues compared to normal lung tissues, implying its involvement in the positive regulation of lung cancer. Further, knockout of TIPE2 resulted in significantly reduced proliferation, survival, and migration of human lung cancer cells through modulation of the Akt/mTOR/NF-κB signaling axis. In addition, knockout of TIPE2 also caused arrest in the S phase of the cell cycle of lung cancer cells. As tobacco is the most predominant risk factor for lung cancer, we therefore evaluated the effect of TIPE2 in tobacco-mediated lung carcinogenesis as well. Our results showed that TIPE2 was involved in nicotine-, nicotine-derived nitrosamine ketone (NNK)-, N-nitrosonornicotine (NNN)-, and benzo[a]pyrene (BaP)-mediated lung cancer through inhibited proliferation, survival, and migration via modulation of nuclear factor kappa B (NF-κB)- and NF-κB-regulated gene products, which are involved in the regulation of diverse processes in lung cancer cells. Taken together, TIPE2 possesses an important role in the development and progression of lung cancer, particularly in tobacco-promoted lung cancer, and hence, specific targeting of it holds an enormous prospect in newer therapeutic interventions in lung cancer. However, these findings need to be validated in the in vivo and clinical settings to fully establish the diagnostic and prognostic importance of TIPE2 against lung cancer.

Involvement of twist in NNK exposure-promoted lung cancer cell migration and invasion

Nicotine-derived nitrosamine ketone (NNK), one of the potent carcinogens in cigarette smoke, has been reported to facilitate lung cancer cell migration and invasion. Twist plays an important role in regulating migration and invasion of lung cancer cells. However, it is unclear whether Twist is implicated in NNK-induced migration and invasion of lung cancer cells. Lung cancer cells were exposed to various doses of NNK for four weeks. The expression levels of protein and mRNA were detected by western blot and quantitative real-time polymerase chain reaction (qRT-PCR), respectively. Small interfering RNA (siRNA) was applied to knock down the expression of Twist. The ability of cell migration and invasion was evaluated by wound-healing assay and Transwell invasion assay. NNK exposure increased the levels of Twist protein and mRNA expression in lung cancer cells compared to solvent control. Lung cancer cells exposed to NNK exhibited higher ability of migration and invasion than those with solvent control did. Twist silencing could block NNK-promoted migration and invasion of lung cancer cells. NNK exposure increased the expression levels of N-cadherin mRNA and decreased the expression levels of E-cadherin mRNA in lung cancer cells, which could be modulated by Twist silencing. In conclusion, Twist was involved in NNK-induced migration and invasion of lung cancer cells.

Electronic-cigarette smoke induces lung adenocarcinoma and bladder urothelial hyperplasia in mice

Electronic-cigarettes (E-cigs) are marketed as a safe alternative to tobacco to deliver the stimulant nicotine, and their use is gaining in popularity, particularly among the younger population. We recently showed that mice exposed to short-term (12 wk) E-cig smoke (ECS) sustained extensive DNA damage in lungs, heart, and bladder mucosa and diminished DNA repair in lungs. Nicotine and its nitrosation product, nicotine-derived nitrosamine ketone, cause the same deleterious effects in human lung epithelial and bladder urothelial cells. These findings raise the possibility that ECS is a lung and bladder carcinogen in addition to nicotine. Given the fact that E-cig use has become popular in the past decade, epidemiological data on the relationship between ECS and human cancer may not be known for a decade to come. In this study, the carcinogenicity of ECS was tested in mice. We found that mice exposed to ECS for 54 wk developed lung adenocarcinomas (9 of 40 mice, 22.5%) and bladder urothelial hyperplasia (23 of 40 mice, 57.5%). These lesions were extremely rare in mice exposed to vehicle control or filtered air. Current observations that ECS induces lung adenocarcinomas and bladder urothelial hyperplasia, combined with our previous findings that ECS induces DNA damage in the lungs and bladder and inhibits DNA repair in lung tissues, implicate ECS as a lung and potential bladder carcinogen in mice. While it is well established that tobacco smoke poses a huge threat to human health, whether ECS poses any threat to humans is not yet known and warrants careful investigation.

The ADAM17 protease promotes tobacco smoke carcinogen-induced lung tumorigenesis.

Lung cancer is the leading cause of cancer-related mortality, with most cases attributed to tobacco smoking, in which nicotine-derived nitrosamine ketone (NNK) is the most potent lung carcinogen. The ADAM17 protease is responsible for the ectodomain shedding of many pro-tumorigenic cytokines, growth factors and receptors, and therefore is an attractive target in cancer. However, the role of ADAM17 in promoting tobacco smoke carcinogen-induced lung carcinogenesis is unknown. The hypomorphic Adam17ex/ex mice-characterized by reduced global ADAM17 expression-were backcrossed onto the NNK-sensitive pseudo-A/J background. CRISPR-driven and inhibitor-based (GW280264X, and ADAM17 prodomain) ADAM17 targeting was employed in the human lung adenocarcinoma cell lines A549 and NCI-H23. Human lung cancer biopsies were also used for analyses. The Adam17ex/ex mice displayed marked protection against NNK-induced lung adenocarcinoma. Specifically, the number and size of lung lesions in NNK-treated pseudo-A/J Adam17ex/ex mice were significantly reduced compared with wild-type littermate controls. This was associated with lower proliferative index throughout the lung epithelium. ADAM17 targeting in A549 and NCI-H23 cells led to reduced proliferative and colony-forming capacities. Notably, among select ADAM17 substrates, ADAM17 deficiency abrogated shedding of the soluble IL-6 receptor (sIL-6R), which coincided with the blockade of sIL-6R-mediated trans-signaling via ERK MAPK cascade. Furthermore, NNK upregulated phosphorylation of p38 MAPK, whose pharmacological inhibition suppressed ADAM17 threonine phosphorylation. Importantly, ADAM17 threonine phosphorylation was significantly upregulated in human lung adenocarcinoma with smoking history compared with their cancer-free controls. Our study identifies the ADAM17/sIL-6R/ERK MAPK axis as a candidate therapeutic strategy against tobacco smoke-associated lung carcinogenesis.

Impact of sample preparation upon intracellular metabolite measurements in 3D cell culture systems

IntroductionInterest in cell culture metabolomics has increased greatly in recent years because of its many potential applications and advantages (e.g., in toxicology). The first critical step for exploring the cellular metabolome is sample preparation. For metabolomics studies, an ideal sample preparation would extract a maximum number of metabolites and would enable reproducible, accurate analysis of a large number of samples and replicates. In addition, it would provide consistent results across several studies over a relatively long time frame.ObjectivesThis study was conducted to evaluate the impact of sample preparation strategies on monitoring intracellular metabolite responses, highlighting the potential critical step(s) in order to finally improve the quality of metabolomics studies.MethodsThe sample preparation strategies were evaluated by calculating the sample preparation effect, matrix factor, and process efficiency (PE) for 16 tobacco exposition-related metabolites, including nicotine, nicotine-derived nitrosamine ketone, their major metabolites, and glutathione, using isotopically-labelled internal standards. Samples were analyzed by liquid chromatography (LC) coupled to high-resolution mass spectrometry (HRMS).ResultsA sample drying step increased losses or variability for some selected metabolites. By avoiding evaporation, good sample preparation recovery was obtained for these compounds. For some metabolites, the cell or culture type impacted PE and matrix factor.ConclusionIn our sample preparation protocol, the drying–reconstitution step was identified as the main cause of metabolite losses or increased data variability during metabolomics analysis by LC-HRMS. Furthermore, PE was affected by the type of matrix. Isotopologue internal standards fully compensate losses or enhancements.

The effect of diet and exercise on tobacco carcinogen-induced lung cancer.

In previous studies, we found that low-carbohydrate (CHO) diets reduced the incidence of tumors in mice genetically predisposed to cancer. However, because >90% of human cancers arise via carcinogen-induced somatic mutations, we investigated, herein, the role that different types and levels of CHO, protein and lipid play in lung cancer induced by the tobacco-specific carcinogen, nicotine-derived nitrosamine ketone (NNK) in A/J mice. We found lowering CHO levels significantly reduced lung nodules and blood glucose levels. We also found that soy protein was superior to casein and that coconut oil was ineffective at reducing lung nodules. Diets containing amylose or inulin (at 15% of total calories), soy protein (at 35%) and fat (at 50%, 30% being fish oil) were the most effective at reducing lung nodules. These fish oil-containing diets increased plasma levels of the ketone body, β-hydroxybutyrate, while reducing both insulin and 8-isoprostane in plasma and bronchoalveolar interleukin-12 and lung PGE2 levels. After only 2 weeks on this diet, the levels of γ-H2AX were significantly reduced, 24 hours after NNK treatment. Housing these mice in two-tiered rat cages with exercise wheels led to similar mouse weights on the different diets, whereas keeping mice in standard mouse cages led to both significant weight differences between the low-CHO, soy protein, fish oil diet and Western diet and substantially more lung nodules than in the two-tiered cages. Our results suggest that low-CHO, soy protein, fish oil-containing diets, together with exercise, may reduce the incidence of lung cancer.

Development of a heart-cutting supercritical fluid chromatography-high-performance liquid chromatography coupled to tandem mass spectrometry for the determination of four tobacco-specific nitrosamines in mainstream smoke

This paper proposed a newly developed heart-cutting two-dimensional supercritical fluid chromatography-high-performance liquid chromatography system coupled to tandem mass spectrometry (SFC-HPLC-MS/MS) for the determination of four tobacco-specific nitrosamines (TSNAs) in cigarette mainstream smoke. The orthogonality of five SFC columns and two HPLC columns was evaluated. The 1-AA column was applied for the first dimensional (1D) SFC separation to isolate the target compounds from the complex cigarette smoke matrices, and a trapping column in conjunction with an isocratic pump was employed to capture the 1D elutes. Then, the trapped 1D elutes were transferred into the C18 column through a two-position/six-port valve for the second dimensional (2D) analysis. The ion suppression was significantly reduced by the established SFC-HPLC system; meanwhile, the matrix interferences were eliminated as the results demonstrated. A dynamic range between 0.1 and 20ng/mL was achieved with LOQs of 0.72μg/cig for N-nitrosonornicotine (NNN), 0.66μg/cig for nicotine-derived nitrosamine ketone (NNK), 0.81μg/cig for N-nitrosoanatabine (NAT), and 0.39μg/cig for N-nitrosoanabasine (NAB). All the results revealed that the presented method exhibited good repeatabilities and recoveries and could be used as a rapid and reliable approach for routine analysis of TSNAs in mainstream smoke.

Fruit and vegetable consumption, cigarette smoke, and leukocyte mitochondrial DNA copy number

Mitochondrial dysfunction is an important component of the aging process and has been implicated in the development of many human diseases. Mitochondrial DNA copy number (mtDNAcn), an indirect biomarker of mitochondrial function, is sensitive to oxidative damage. Few population-based studies have investigated the impact of fruit and vegetable consumption and cigarette smoke (2 major sources of exogenous antioxidants and oxidants) on leukocyte mtDNAcn. We investigated the association between fruit and vegetable consumption, cigarette smoke, and leukocyte mtDNAcn based on data from the Nurses' Health Study (NHS). Data from 2769 disease-free women in the NHS were used to examine the cross-sectional associations between dietary sources of antioxidants, cigarette smoke, and leukocyte mtDNAcn. In vitro cell-based experiments were conducted to support the findings from the population-based study. In the multivariable-adjusted model, both whole-fruit consumption and intake of flavanones (a group of antioxidants abundant in fruit) were positively associated with leukocyte mtDNAcn (P-trend = 0.005 and 0.02, respectively), whereas pack-years of smoking and smoking duration were inversely associated with leukocyte mtDNAcn (P-trend = 0.01 and 0.007, respectively). These findings are supported by in vitro cell-based experiments showing that the administration of naringin, a major flavanone in fruit, led to a substantial increase in mtDNAcn in human leukocytes, whereas exposure to nicotine-derived nitrosamine ketone, a key carcinogenic ingredient of cigarette smoke, resulted in a significant decrease in mtDNAcn of cells (all P < 0.05). Further in vitro studies showed that alterations in leukocyte mtDNAcn were functionally linked to the modulation of mitochondrial biogenesis and function. Fruit consumption and intake of dietary flavanones were associated with increased leukocyte mtDNAcn, whereas cigarette smoking was associated with decreased leukocyte mtDNAcn, which is a promising biomarker for oxidative stress-related health outcomes.

Potential Effect of Tobacco Consumption through Smoking and Chewing Tobacco on IL1beta Protein Expression in Chronic Periodontitis Patients: In Silico Molecular Docking Study.

Detrimental effect of bad oral habits, such as smoking and chewing tobacco, on chronic periodontitis (CP) manifest chronic inflammation of gingival tissues which majorly results in gum bleeding, and teeth loss. A genetic association study of Interleukin 1 beta (IL1β) has been conducted in CP patients having smoking and chewing tobacco habits in regular life style. A molecular docking study has been consequently done to analyze the effect of tobacco on CP progression in depth. All statistical evaluation has been done by using SPSS v16.0. The findings of the study show the significant association of IL1β gene polymorphisms with CP increased susceptibility in combination of oral habits as mentioned earlier. The docking profile has showed the highest binding affinity of IL1β protein with the Nicotine derived Nitrosamine Ketone (NNK), one of the derivatives of nicotine which is in-taken through the habits associated with smoking and chewing tobacco. Nicotine, N-nitrosoanabasine, and N-nitrosonornicotine, the other derivatives, have also demonstrated significant impact over the IL1β protein-caused altered expression. Thus, this study concluded that the harmful effect of tobacco may increase the inflammation in periodontia by inducing the inflammatory active site of the IL1β protein in the CP patients.

EGFR-AS1/HIF2A regulates the expression of FOXP3 to impact the cancer stemness of smoking-related non-small cell lung cancer.

Background:Early data showed that FOXP3 could induce epithelial-mesenchymal transition by stimulating the Wnt/β-catenin signaling pathway in non-small cell lung cancer (NSCLC). However, how the expression of FOXP3 is regulated in NSCLC remains unknown. We thus explored the impacts of the long noncoding RNA EGFR antisense RNA 1 (EGFR-AS1) and hypoxia-inducible factor-2A (HIF2A) on FOXP3 expression and the cancer stemness of NSCLC.Methods:Lung tissues samples from 87 patients with NSCLC and two NSCLC cell lines were used in this study. The regulation of FOXP3 and lung cancer cell stemness by EGFR-AS1 and HIF2A was determined at molecular levels in NSCLC tissue samples and cultured cells in the presence/absence of the smoking carcinogen, 4-(N-methyl-N-nitrosamino)-1-(3-pyridyl)-1-butanone (NNK) (also known as nicotine-derived nitrosamine ketone). The results were confirmed in tumor xenograft models.Results:We found that NNK decreased the expression of EGFR-AS1 in the long term, but increased the expression of HIF2A and FOXP3 to stimulate lung cancer cell stemness. EGFR-AS1 significantly inhibited FOXP3 expression and NSCLC cell stemness, whereas HIF2A obviously promoted both. The enhancement of lung cancer stemness by FOXP3 was, at least partially, via stimulating Notch1, as the inhibition of Notch1 could markedly diminish the effect of FOXP3.Conclusions:FOXP3, the expression of which is under the fine control of EGFR-AS1, is a critical molecule that promotes NSCLC cancer cell stemness through stimulating the Notch1 pathway.

Grass roots approach to control levels of carcinogenic nitrosamines, NNN and NNK in smokeless tobacco products

Due to the extensive ban on public smoking, tobacco companies focused their business on new smokeless tobacco (SLT) products promoting them as a harm reduction strategy and a safer alternative to cigarettes. Two nitrosamines, N′-nitrosonornicotine (NNN) and nicotine-derived nitrosamine ketone (NNK), present in SLT, listed as group 1 human carcinogens by the International Agency for Research on Cancer, are found to be the prime agents for most of cancers in SLT users. This review illustrates the mechanism of cancer induction by NNN and NNK in humans along with factors influencing the formation of NNN and NNK at various stages of tobacco manufacturing. It reveals the high levels and wide variations of NNN and NNK found among the diverse variety of SLT products sold worldwide. According to a recent report by FDA- Centre for Tobacco Products, reducing levels of nitrosamines in SLT products could greatly enhance the quality of life by reducing mortality, morbidity and medical expenditures due to cancer. For the first time, grass root approaches to minimize the levels of NNN and NNK in tobacco, from plant growth to the finished products, have been systematically compiled as they have the potential to contribute to reducing tobacco related disease burden.