Impact of Tobacco Smoking on Health Care Utilization and Medical Costs in Chronic Obstructive Pulmonary Disease,Coronary Heart Disease and Diabetes

Objective To determine the impact of smoking on disease-specific health care utilization and medical costs in patients with chronic non-communicable diseases(NCDs).Methods Participants were middle-aged and elderly adults with chronic NCDs from a prospective cohort in China.Logistic regressions and linear models were used to assess the relationship between tobacco smoking,health care utilization and medical costs.Results Totally,1020 patients with chronic obstructive pulmonary disease(COPD),3144 patients with coronary heart disease(CHD),and 1405 patients with diabetes were included in the analysis.Among patients with COPD,current smokers(β:0.030,95%CI:−0.032-0.092)and former smokers(β:0.072,95%CI:0.014-0.131)had 3.0%and 7.2%higher total medical costs than never smokers.Medical costs of patients who had smoked for 21-40 years(β:0.028,95%CI:−0.038-0.094)and≥41 years(β:0.053,95%CI:−0.004β0.110)were higher than those of never smokers.Patients who smoked≥21 cigarettes(β:0.145,95%CI:0.051-0.239)per day had more inpatient visits than never smokers.The association between smoking and health care utilization and medical costs in people with CHD group was similar to that in people with COPD;however,there were no significant associations in people with diabetes.Conclusion This study reveals that the impact of smoking on health care utilization and medical costs varies among patients with COPD,CHD,and diabetes.Tobacco control might be more effective at reducing the burden of disease for patients with COPD and CHD than for patients with diabetes.

When smoke meets gut:deciphering the interactions between tobacco smoking and gut microbiota in disease development

Tobacco smoking is a prevalent and detrimental habit practiced worldwide,increasing the risk of various diseases,including chronic obstructive pulmonary disease(COPD),cardiovascular disease,liver disease,and cancer.Although previous research has explored the detrimental health effects of tobacco smoking,recent studies suggest that gut microbiota dysbiosis may play a critical role in these outcomes.Numerous tobacco smoke components,such as nicotine,are found in the gastrointestinal tract and interact with gut microbiota,leading to lasting impacts on host health and diseases.This review delves into the ways tobacco smoking and its various constituents influence gut microbiota composition and functionality.We also summarize recent advancements in understanding how tobacco smoking-induced gut microbiota dysbiosis affects host health.Furthermore,this review introduces a novel perspective on how changes in gut microbiota following smoking cessation may contribute to withdrawal syndrome and the degree of health improvements in smokers.

Impact of Village-based Health Education of Tobacco Control on the Current Smoking Rate in Chinese Rural Areas

The number of smokers in Chinese rural areas is more than 200 million, which is twice that in cities. It is very significant to carry out tobacco control interventions in rural areas. We performed this community intervention study to evaluate the efficacy of village-based health education of tobacco control on the male current smoking rate in rural areas. The population of this study was the males above 15 years old from 6 villages in rural areas. The villages were randomly assigned to intervention group or control group（3 villages in each group）. Self-designed smoking questionnaire was applied. The intervention group received the village-based health education of tobacco control for one year. The primary outcome measurement was the male current smoking rate. In the baseline investigation, completed surveys were returned by 814 male residents from the control group and 831 male residents from the intervention group. The male current smoking rate in the control group and the intervention group was 61.2% and 58.5%, respectively, before intervention. There was no significant difference between these two groups（P〉0.05）. After one-year intervention, the current smoking rate in the intervention group（51.2%） was significantly lower than that in the control group（62.8%）（P〈0.001）. Our study suggested that the village-based health education of tobacco control was effective in lowering the male current smoking rate in rural areas, which could be a suitable and feasible way for tobacco control in the Chinese rural areas.

Tobacco, air pollution, environmental carcinogenesis, and thoughts on conquering strategies of lung cancer

Each year there will be an estimated 2.1 million new lung cancer cases and 1.8 million lung cancer deaths worldwide.Tobacco smoke is the No.1 risk factors of lung cancer,accounting for>85%lung cancer deaths.Air pollution,or haze,comprises ambient air pollution and household air pollution,which are reported to cause 252,000 and 304,000 lung cancer deaths each year,respectively.Tobacco smoke and haze(hereafter,smohaze)contain fine particles originated from insufficient combustion of biomass or coal,have quite similar carcinogens,and cause similar diseases.Smohaze exert hazardous effects on exposed populations,including induction of a large amount of mutations in the genome,alternative splicing of mRNAs,abnormalities in epigenomics,initiation of tumor-promoting chronic inflammation,and facilitating immune escape of transformed cells.Tackling smohaze and development of multi-targets-based preventive and therapeutic approaches targeting smohaze-induced carcinogenesis are the key to conquer lung cancer in the future.

Ultrastructural changes in embryoic neuroepithelial cells caused by passive smoking in golden hamsters at different periods of pregnancy: A randomized controlled trial

BACKGROUND： Tobacco smoke exposure is recognized as a health risk for pregnant women and it is increasingly evident that tobacco smoke affects the development of brain. Recently, associations between maternal smoking during pregnancy and subsequent mental health problems in offspring have been reported. OBJECTIVE： To observe the effect of passive smoking on the morphology of nerve tissues and the ultrastructure of neuroepithelial cells during embryogenesis in golden hamster at different pregnant period. DESIGN： A randomized control study. SETTING： Department of Histology and embryology, Qingdao University. MATERIALS： Adult golden hamsters, including 40 males and 40 females that had not delivered, weighing （105±5） g, were provided by Shenyang Changsheng Biotechnology, Co.,Ltd. At 20 ： 00 - 21 ： 00, one male and one female were matched in each cage, and their mating was observed. The vaginal swabs were examined the next day and the day of positive sperm was taken as embryonic day 1 （E1）. METHODS： The experiment was completed in the Department of Histology and Embryology of Qingdao University from September 2001 to September 2003. （1） Abnormality caused by smoking, grouping and model establishment： A total of 40 healthy pregnant golden hamsters were randomly divided into control group （n =20） and experimental group （n =20）. The hamsters in the experimental group were exposed to tobacco smoke from embryonic day 4 to 7, 3 times per day, continuously 1 hour per time, 1 cigarette per golden hamster, for 4 consecutive days in the self-made chamber. The animals in the control group were given the same conditions as those in the experimental group except exposure to smoke. （2） Observation with transmission electron microscope： According to different gestational ages, the experimental group and the control group were all divided 4 subgroups （Groups A, B, C and D） respectively, and 5 hamsters in each subgroup. The pregnant golden hamsters were anaesthetized with 1 g/L pentobarbital sodium at 12 ： 00 and 18 ： 00 at E8, 8 ： 00 at E9 and 8 ： 00 at E10, and all the pregnant uteruses were divulsed under the stereomicroscope. The development of the neural plate, neural groove and neural tube were observed. Meanwhile, the amount of normal embryos and abnormal embryos including the neural tube defect ratios were recorded. （3） Electron microscopic specimen preparation and observation： Three embryos of each group ad libtium were fixed. The alternations of neuroepithelial ultrastrnctures were observed with transmission and scanning electron microscopes. MAIN OUTCOME MEASURES： （1） The incidences of abnormality of nervous system development were observed under stereomicroscope and scanning electron microscope in smoking group and the control group; （2） Alternations of neuroepithelial ultrastructures were observed with transmission electron microscope. RESULTS： All the 40 pregnant golden hamsters were involved in the final analysis. （1） Manifestations and incidence of nervous system dysplasia： Passive smoking could induce dymorphogenesis during neurnlation, which mainly presented as growth retardation, spina bifida and failure of formation of neural tubes; The incidences of the nervous system dysplasia in the experimental groups [20%（10/49）, 27%（14/51）, 32% （19/59）, 27% （17/63）] were higher than those in the corresponding control groups [0. 2% （1/57）, 4% （2/53）, 4% （2/52）, P 〈 0.01]. （2） Histomorphological changes at different time points after spermatiation observed with transmission and scanning electron microscopes： In the control group, the embryos formed C-shape columned embryos, anterior and posterior neuropores were all closure at 10 ： 00 on E10; In the experimental group, unfused anterior and posterior neuropores still could be found, and some embryos presented spina bifida at 10 ： 00 on E10. In the control group, neuroepithelial cell arranged tidily and closely, the boundary of the cells was clear, the flee surface of neuroepithelial had a mass of long and regular microvillus, and the surface of mesenchymal cell around the neuroepithelium had many processes which mutually related at 12 ： 00 on E8. In the experimental group, the neuroepithelial cells arranged irregularly and the intercellular spaces became wide at 12 ： 00 on E8. The apical portion of many neuroepithelial cells bulged into the lumen and many microvilli were shorted and swollen. The quantity of the microvillus reduced gradually, evenly disappeared with the increasing of gestational age at 18：00 on E8. Under transmission electron microscope, the neuroepithelial cells in experimental embryos arranged irregularly. There were many visible materials in the intercellular space which increased the breadth and anomaly. It was apparent that passive smoking evoked major alterations in neuroepithelial cytoarchitecture. Junctional complex reduced. Many microvilli were shorted and swollen, even the apical portion of many neuroepithelial cells bulged, and abscised into the lumen. A lot of vacuolation appeared in the cytoplasm of neuroepithelia and mesenchymal cell around the neuroepithelium. The cristae of mitochondria reduced even disappeared, and some mitochondria became elongate. Irregular nuclear, increased heterochromatin and karyopycnosis/karyorrhexis were observed easily. Perinuclear cisternae partially swelled and embraced tangible material （maybe the material from nuclear）. Some death cells separated into a lot of apoptotic bodies. Some apoptotic bodies were found in the cytoplasm of other healthy-looking or healthy cells. CONCLUSION： Passive smoking may induce degeneration, apoptosis, and cells loss in the neural epithelium, thereby result in failure of formation and differentiation of neural tube. It is an important way by which passive smoking caused neural tube defects.

8-Hydroxydeoxyguanosine as a Biomarker of Oxidative DNA Damage Induced by Environmental Tobacco Side-stream Smoke and Its Mechanism

To study the genotoxicity effect of environmental tobacco side-stream smokes (ETSS) on oxidative DNA damage and its molecular mechanism. Methods DNA adduct 8-hydroxydeoxyguanosine (8-OHdG) was used as a biomarker of oxidative DNA damage. The level of 8-OHdG in DNA exposed to ETSS was detected by high performance liquid chromatography with electrochemical detection. Organic and inorganic components in ETSS were analyzed by gas chromatography-mass spectrum and atomic absorption spectrum respectively. Results Particle matters (PMs) and volatile organic compounds (VOCs) in ETSS could directly induce oxidative DNA damage and formation of 8-OHdG. There were 123 and 84 kinds of organic components in PMs and VOCs respectively, and 7 kinds of inorganic components in ETSS. Some components, especially quinones and polyphenols in ETSS, could produce free radicals in vitro by auto-oxidation without any biological activity systems, and with the catalytic reaction of metals, the DNA adduct 8-OHdG was produced. Conclusion ETSS have biological oxidative effect on DNA in vitro and in vivo, and expressed direct genotoxicity. 8-OHdG is a valuable biomarker of oxidative DNA damage.

CONCERNING THE RELATION OF TOBACCOGLYCOPROTEIN TO BUERGER'S DISEASE

Objective To comprehend the reiation of tobacco glycoprotein (TGP) to Buerger,s disease.Metbods TGP was isolated from crude tobacco leaves by basic immunologic techniques. Serum anti- TGPantibodies were tested by Western blot analysis in 11 patients with Buerger,s disease, 15 healthy male smokers and11 nonsmoking healthy male subjects. Results 1. TGP is a dark brown protein of molecular weight 14000. It maybe a subunit of some high molecular weight protein, and exists in crude tobacco leaves. 2. Western blot analysisshowed that 81.81% of patients with Buerger’s disease (9/11), 33.33% of healthy smokers (5/15) and 27.27% ofhealthy nonsmokers (3/11) had serum anti- TGP antibodies. There was significant dtherence between patientswith Buerger,s disease and two control groups (P<0.05), and no signilicant dtherence between both control groups(P>0.05). Conclusion TGP does play an important role in the pathogenesis of Buerger’s disease. As anti - TGPantibodies are also found in some control subjects, it is speculated that other etiologic factors might coordinatelycontribute to the specifc vascular response to TGP in susceptible subjects.

Widening socioeconomic disparity in lung cancer incidence among men in New South Wales, Australia, 1987–2011

Objective：We assessed the trends in lung cancer incidence over a 25-year period by socioeconomic groups for men in New South Wales（NSW）,Australia.Methods：Men diagnosed with lung cancer between 1987 and 2011 were divided into five quintiles according to an Index of Education and Occupation（IEO）.We assessed relative socioeconomic differences over time by calculating age-standardized incidence ratios（SIRs）by 5-year period of diagnosis,and estimated absolute differences by comparing the observed and expected numbers of cases using the highest IEO quintile as the reference.Results：Lung cancer incidence for men decreased from 1987 to 2011 for all IEO quintiles,with a greater rate of decline for men living in the highest IEO areas.Thus,the relative disparity increased significantly over the 25-year period（P=0.0006）.For example,the SIR for the lowest IEO quintile increased from 1.28 during 1987–1991 to 1.74during 2007–2011.Absolute differences also increased with the proportion of＂potentially preventable＂cases doubling from 14.5% in 1987–1991 to 30.2% in 2007–2011.Conclusions：Despite the overall decline in lung cancer incidence among men in NSW over the past 25 years,there was a significant increase in disparity across socioeconomic areas in both relative and absolute terms.

A Decision Tree Approach for Predicting Smokers’Quit Intentions

This paper presents a decision tree approach for predicting smokers＇ quit intentions using the data from the International Tobacco Control Four Country Survey. Three rule-based classification models are generated from three data sets using attributes in relation to demographics, warning labels, and smokers＇ beliefs. Both demographic attributes and warning label attributes are important in predicting smokers＇ quit intentions. The model＇s ability to predict smokers＇ quit intentions is enhanced, if the attributes regarding smokers＇ internal motivation and beliefs about quitting are included.

An evaluation of mass,number concentration,chemical composition and types of particles in a cafeteria before and after the passage of an antismoking law

This study assessed air quality indicators before and after enactment of the Spanish anti-smoking law. Mass and number concentrations and the chemical composition of particles were evaluated. Microscopy analyses were also conducted. Real time concentrations of PMlo, PM2.s, PM1 and ultrafine particles were measured under ventilated and non-ventilated conditions and PMlo samples were collected for detailed inorganic and organic chemical characterization. Before enactment of the law in 2010, tobacco smoke produced significant indoor ambient particulate matter pollution, with elevated particulate matter mass concentrations （PM10 and PM1 concentrations of 122-220 and 48-85 Dg/m3, respectively） and ultrafine particle numbers （75,000 and 48,000 cm ~ under ventilated and non-ventilated conditions, respectively）. Typical tobacco smoke tracers including iso- and anteiso-alkanes and elements including La and Ce from the ignition of lighters were abundant. Additionally, several toxic substances derived from tobacco smoke, including Cd （3.1 ng/m3） and benzo[a]pyrene （1.0 ng/m3） were present at concentrations approximately 10 times greater than those measured after enactment of the anti-smoking law. The anti-smoking law sig- nificantly reduced exposure to potentially toxic compounds by approximately 90%. This law is expected to have a positive health impact, particularly for people who spend considerable time in affected envi- ronments, such as employees.

Current cancer situation in China:good or bad news from the 2018 Global Cancer Statistics?

Cancer is the leading cause of death in China and depicting the cancer pattern of China would provide basic knowhows on how to tackle it more effectively.In this study we have reviewed several reports of cancer burden,including the Global cancer statistics 2018 and Cancer statistics in China,2015,along with the GLOBCAN 2018 online database,to investigate the differences of cancer patterns between China,the United States(USA)and the United Kingdom(UK).An estimated 4.3 million new cancer cases and 2.9 million new cancer deaths occurred in China in 2018.Compared to the USA and UK,China has lower cancer incidence but a 30%and 40%higher cancer mortality than the UK and USA,among which 36.4%of the cancer-related deaths were from the digestive tract cancers(stomach,liver,and esophagus cancer)and have relatively poorer prognoses.In comparison,the digestive cancer deaths only took up≤5%of the total cancer deaths in either USA or UK.Other reasons for the higher mortality in China may be the low rate of early-stage cancers at diagnosis and non-uniformed clinical cancer treatment strategies performed by different regions.China is undergoing the cancer transition stage where the cancer spectrum is changing from developing country to developed country,with a rapidly increase cancer burden of colorectal,prostate,female breast cancers in addition to a high occurrence of infection-related and digestive cancers.The incidence of westernized lifestyle-related cancers in China(i.e.colorectal cancer,prostate,bladder cancer)has risen but the incidence of the digestive cancers has decreased from 2000 to 2011.An estimated 40%of the risk factors can be attributed to environmental and lifestyle factors either in China or other developed countries.Tobacco smoking is the single most important carcinogenic risk factor in China,contributing to~24.5%of cancers in males.Chronic infection is another important preventable cancer contributor which is responsible for~17%of cancers.Comprehensive prevention and control strategies in China should include effective tobacco-control policy,recommendations for healthier lifestyles,along with enlarg-ing the coverage of effective screening,educating,and vaccination programs to better sensitize greater awareness control to the general public.

Current opinion on the importance of pulmonary rehabilitation in patients with chronic obstructive pulmonary disease

Multidisciplinary pulmonary rehabilitation （PR） is a .widely accepted non-pharmacological treatment method that tries to improve exercise tolerance and quality of life in chronic obstructive pulmonary disease （COPD） and non-COPD patients, together with reduction in medical services use.1 The aim of PR is to help respiratory patients to reach and keep a maximal functioning and independence level within community^2 The patients severely affected by other pulmonary diseases than COPD are benefiting of intensive PR and the degree of improvement is similar to that obtained in COPD^3

Identification of CYP 2A6 inhibitors in an effort to mitigate the harmful effects of the phytochemical nicotine

Aim:In this study,our goal was to study the inhibition of nicotine metabolism by P4502A6,as a means for reduction in tobacco use and consequently the prevention of smoking-related cancers.Nicotine,a phytochemical,is an addictive stimulant,responsible for the tobacco-dependence in smokers.Many of the other phytochemicals in tobacco,including polycyclic aromatic hydrocarbons,N-nitrosamines,and aromatic amines,are potent systemic carcinogens.Tobacco smoking causes about one of every five deaths in the United States annually.Nicotine plasma concentration is maintained by the smokers’smoking behavior within a small range.Nicotine is metabolized by cytochrome P450s 2A6 and 2A13 to cotinine.This metabolism causes a decrease in nicotine plasma levels,which in turn leads to increased tobacco smoking,and increased exposure to the tobacco carcinogens.Methods:Using the phytochemical nicotine as a lead structure,and taking its interactions with the P4502A6 binding pocket into consideration,new pyridine derivatives were designed and synthesized as potential selective mechanism-based inhibitors for this enzyme.Results:The design and synthesis of two series of novel pyridine-based compounds,with varying substituents and substitution locations on the pyridine ring,as well as their inhibitory activities on cytochrome P4502A6 and their interactions with its active site are discussed here.Substitutions at position 3 of the pyridine ring with an imidazole or propargyl ether containing group showed the most optimal interactions with the P4502A6 active site.Conclusion:The pyridine compounds with an imidazole or propargyl ether containing substituent on position 3 were found to be promising lead compounds for further development.Hydrogen-bonding interactions were determined to be crucial for effective binding of these molecules within the P4502A6 active site.

Effects of N-acetylcysteine on Clara cells in rats with cigarette smoke exposure

Background The number of Clara cells and the Clara cell 16-kDa protein （CC16） levels of the lung decrease in patients with chronic obstructive pulmonary disease （COPD）. N-acetylcysteine （NAC） is a powerful antioxidant and can reduce the frequency of acute exacerbations of COPD. But the exact mechanism is unclear. The present study was designed to investigate the effects of NAC on Clara cells in rats with cigarette smoke exposure. Methods Eighteen adult male Wistar rats were randomly divided into 3 groups, 12 exposed to cigarette smoke （CS） thrice a day, 10 cigarettes for 30 minutes each time for 1 week, without （CS group） or with （CS＋NAC group） oral intake of NAC 80 mg·kg^-1·d^-1, and another 6 rats exposed to fresh air （control group）. Clara cells were observed by an electron microscope. The mRNA expression of CC16 and CC16 protein in lungs were determined by reverse transcription polymerase chain reaction （RT-PCR） and immunohistochemistry respectively. The glutathion （GSH） level in plasma and lung tissue were tested by fluorimetry assay. Results Compared with the controls, the pathologic score of small airways significantly increased in the CS exposed rats （20.3±14.7 vs. 53.7±11.5, P 〈0.05）. The Clara cell particles in cytoplasm decreased in the CS group （P 〈0.05）. The percentage of CC16-positive cells in bronchioles in the CS group （27.8±4.3 and 29.5±2.4 in terminal bronchioles and respiratory bronchioles, respectively） significantly decreased as compared with the control group （37.1±3.8 and 43.8±5.8 in terminal bronchioles and respiratory bronchioles, respectively） （P 〈0.05）. No significant difference was observed in GSH level （（181±26） nmol/L in the control group vs. （170±18） nmol/L in the CS group） between the two groups. After treatment with NAC, the pathologic score of small airways （24.1±17.5） decreased （P 〈0.05）. Clara cell particles in cytoplasm of Clara cells increased and GSH level in plasma （（213±40） nmol/L vs. （170±18） nmol/L in the CS group） increased too （P 〈0.05）, while the increase in the proportions of CC16 positive cells in bronchioles （30.1±6.4 and 34.3±6.3 in terminal bronchioles and respiratory bronchioles, respectively） did not reach the statistical significance （P 〉0.05）. No significant difference was found in the expression of CC16 mRNA among the three groups. Correlation analysis indicated that the percentage of CC16-positive cells in bronchioles negatively correlated with the pathologic score of small airways （r = -0.592, P 〈0.05）, but not with GSH level. Conclusions One-week CS exposure decreased the number of Clara cells and the expression of CC16 in bronchioles in rats. NAC might provide protection of the Clara cells from oxidative damage and possibly through the elevation of the synthesis and secretion of CC16. These data indicate that NAC decreases airway inflammation induced by CS via induction of CC16.

Effect of cigarette smoke extract on proliferation of rat pulmonary artery smooth muscle cells and the relevant roles of protein kinase C

Background Increased proliferation of pulmonary vascular cells and muscularisation of pulmonary vessels are frequently observed in human smokers and in animals exposed to cigarette smoke. To elucidate the molecular mechanisms leading to these changes, we studied the in vitro effect of cigarette smoke extract （CSE） on proliferation of pulmonary artery smooth muscle cells （PASMCs） and activation of protein kinase C （PKC）, an important kinase implicated in cell proliferation. Methods PASMCs cultured from 12 normal Wistar rats were studied in the following conditions： （1） PASMCs were exposed to different concentrations of CSE for 24 hours, then MTT colorimetric assay was used for detection of cell proliferation. Cell viability was assessed by trypan blue exclusion. （2） PASMCs were pre-incubated with phorbol 12-myristate 13-acetate （PMA） for 24 hours or Ro31-8220 for 30 minutes before exposure to 5% CSE for 24 hours. Cell proliferation was examined by MTT colorimetric assay, cell cycle analysis and proliferating cell nuclear antigen （PCNA） immunocytochemical staining. （3） PASMCs were exposed to 5% CSE for 24 hours. Then PKC-a mRNA expression was detected by reverse transcription-polymerase chain reaction （RT- PCR） and protein expression by Western blotting, while PKC-α translocation was observed by immunofluorescence staining and confocal microscopy. （4） PASMCs were transfected with specific antisense oligodeoxynucleotides against PKC-a 6 hours before exposure to 5% CSE for 24 hours. PKC-α protein expression and cell proliferation were detected by methods described previously. Results （1） Low concentration of CSE （5%） increased proliferation of PASMCs, whereas high concentrations （20%, 30%） were inhibitory as a result of cytotoxicity. （2） The value of absorbance （Value A）, proliferation index （PI）, S-phase cell fraction （SPF） and average optical density of PCNA staining in PASMCs from 5% CSE exposure group （0.306 ± 0.033, 0.339 ± 0.033, 0.175 ± 0.021, 0.315 ± 0.038, respectively） were significantly increased compared with those of control group （0.249 ± 0.018, 0.177 ± 0.055, 0.092 ± 0.023, 0.187 ± 0.022, respectively） （P〈0.05）. PKC down-regulation by PMA pretreatment or PKC inhibition by Ro31-8220 pre-incubation abolished the effect of 5% CSE on PASMCs proliferation. （3） After exposure to 5% CSE for 24 hours, PKC-α mRNA and protein expression in PASMCs （1.054 ± 0.078 1.185 ± 0.041, respectively） were much higher than in untreated cells （0.573 ± 0.054, 0.671 ± 0.055, respectively） （P〈0.01）. Moreover, 5% CSE induced a translocation of PKC-a from cytoplasm toward the perinuclear area and into the nucleus. （4） Specific antisense oligodeoxynucleotides against PKC-a reduced 5% CSE-induced expression of PKC-a protein （0.713 ± 0.047 vs 1.180 ± 0.056）, also abolished the effect of 5% CSE on PASMCs proliferation significantly. Conclusions CSE can be cytotoxic at high concentrations. But at low concentrations, it makes a mitogenic effect on cultured PASMCs. PKC, especially its alpha isozyme, seems to play an important role in CSE-induced proliferation of PASMC.

Identification of an E3 ligase-encoding gene RFWD3 in non-small cell lung cancer

In order to unveil ubiquitin pathway genes (UPGs) that are essential for non-small cell lung cancer (NSCLC) cell proliferation,we recently conducted a siRNA screening experiment to knockdown the expression of 696 UPGs found in the human genome in A549 and H1975 NSCLC cells.We found that silencing of one of the candidates,RFWD3 that encodes an E3 ubiquitin ligase essential for the repair of DNA interstrand cross-links inresponse to DNA damage,led to dramatic inhibition of NSCLC cell proliferation with significant Z-scores.Knockdown of RFWD3 suppressed colony forming activity of NSCLC cells.We further evaluated the significance of RFWD3 in NSCLCs and found that this gene was more elevated in tumor samples than in paired normal lung tissues and was inversely associated with the clinical outcome of patients with NSCLC.Moreover,RFWD3 expression was significantly higher in smokers than in non-smokers.These results show for the first time that RFWD3 is required for NSCLC cell proliferation and may have an important role in lung carcinogenesis.

Carcinogens that induce the A：T 〉 T：A nucleotide substitutions in the genome

Recently, Ng et al. reported that the A：T 〉 T：A substitutions, proposed to be a signature of aristolochic acid （AA） exposure, were detected in 76/98 （78%） of patients with hepatocellular carcinoma （HCC） from the Taiwan Province of China, and 47% to 1.7% of HCCs from the Chinese mainland and other countries harbored the nucleotide changes. However, other carcinogens, e.g., tobacco carcinogens 4-aminobiphenyl and 1,3-butadiene, air toxic vinyl chloride and its reactive metabolites chloroethylene oxide, melphalan and chlorambucil, also cause this signature in the genome. Since tobacco smoke is a worldwide public health threat and vinyl chloride distributes globally and is an air pollutant in Taiwan Province, the estimation of the patients＇ exposure history is the key to determine the ＂culprit＂ of the A：T 〉 T：A mutations. Apparently, without estimation of the patients＇ exposure history, the conclusion of Ng et al, is unpersuasive and misleading.

Degradation of SARS-CoV-2 receptor ACE2 by the E3 ubiquitin ligase Skp2 in lung epithelial cells

An unexpected observation among the COVID-19 pandemic is that smokers constituted only 1.4%–18.5%of hospitalized adults,calling for an urgent investigation to determine the role of smoking in SARS-CoV-2 infection.Here,we show that cigarette smoke extract(CSE)and carcinogen benzo(a)pyrene(BaP)increase ACE2 mRNA but trigger ACE2 protein catabolism.BaP induces an aryl hydrocarbon receptor(AhR)-dependent upregulation of the ubiquitin E3 ligase Skp2 for ACE2 ubiquitination.ACE2 in lung tissues of non-smokers is higher than in smokers,consistent with the findings that tobacco carcinogens downregulate ACE2 in mice.Tobacco carcinogens inhibit SARS-CoV-2 spike protein pseudovirions infection of the cells.Given that tobacco smoke accounts for 8 million deaths including 2.1 million cancer deaths annually and Skp2 is an oncoprotein,tobacco use should not be recommended and cessation plan should be prepared for smokers in COVID-19 pandemic.