Cigarette smoking and alcohol drinking and esophageal cancer risk in Taiwan Residents women

AIM:To investigate the etiology of esophageal cancer among Taiwan Residents women.METHODS:This is a multi-center,hospital-based,case-control study.Case patients consisted of women who were newly diagnosed and pathology-proven to have esophageal squamous cell carcinoma(ESCC) from three large medical centers(one from Northern and two from Southern Taiwan,respectively)between August 2000 and December 2008.Each ESCC patient was matched with 4 healthy women based on age(within 3 years)and hospital of origin,from the Department of Preventive Medicine in each hospital.A total of 51 case patients and 204 controls,all women,were studied.RESULTS:Frequencies of smokers and drinkers among ESCC patients were 19.6%and 21.6%,respectively,which were significantly higher than smokers(4.4%) and drinkers(4.4%)among controls(OR=4.07,95%CI:1.36-12.16,P=0.01;OR=3.55,95%CI:1.03-12.27,P=0.04).Women who drank an amount of alcohol more than 158 g per week had a 20.58-fold greater risk(95%CI:1.72-245.62,P=0.02)of ESCC than those who never drank alcohol after adjusting for other covariates,although the sample size was small.CONCLUSION:Cigarette smoking and alcohol drinking,especially heavy drinking,are the major risks for developing ESCC in Taiwan Residents women.

The Impact of Cigarette Smoking on Metabolic Syndrome

Metabolic syndrome （MetS） is a constellation of interconnected cardiometabolic disorders, including obesity, hyperglycemia, dyslipidemia, and elevated blood pressure. MetS is a precursor to type 2 diabetes mellitus （T2DM） and cardiovascular disease （CVD）; it increases the risk of T2DM by 3-4 times[11 and the risk of CVD by 1.4-fold[21, and is more prevalent in obese individuals. As the obesity rates increase, the prevalence of MetS in the population is increased. In 2006, the global prevalence of MetS in adults was estimated to be 20%-25%TM, and in China, in 2007-2008, using the criteria of the Chinese Joint Committee for Developing Chinese Guidelines on Prevention and Treatment of Dyslipidemia in Adults （JCDCG）, it reached 21.9% among the adult population aged 〉20 vears old[4].

Exercise Training Attenuated Chronic Cigarette Smoking-induced Up-regulation of FIZZ1/RELMα in Lung of Rats

FIZZ/RELM is a new gene family named ＂found in inflammatory zone＂ （FIZZ） or ＂re- sistin-like molecule＂ （RELM）. FIZZ1/RELMct is specifically expressed in lung tissue and associated with pulmonary inflammation. Chronic cigarette smoking up-regulates FIZZ 1/RELMct expression in rat lung tissues, the mechanism of which is related to cigarette smoking-induced airway hyperresponsive- ness. To investigate the effect of exercise training on chronic cigarette smoking-induced airway hyper- responsiveness and up-regulation of FIZZ1/RELMct, rat chronic cigarette smoking model was estab- lished. The rats were treated with regular exercise training and their airway responsiveness was meas- ured. Hematoxylin and eosin （HE） staining, immunohistochemistry and in situ hybridization of lung tissues were performed to detect the expression of FIZZ1/RELMct. Results revealed that proper exercise training decreased airway hyperresponsiveness and pulmonary inflammation in rat chronic cigarette smoking model. Cigarette smoking increased the mRNA and protein levels of FIZZ1/RELMct, which were reversed by the proper exercise. It is concluded that proper exercise training prevents up-regulation of FIZZ1/RELMct induced by cigarette smoking, which may be involved in the mechanism of proper exercise training modulating airway hyperresponsiveness.

THE STUDY ON RELATIONSHIP BETWEEN CIGARETTE SMOKING AND THE p53 PROTEIN AND P21 PROTEIN EXPRESSION IN NON-SMALL LUNG CANCER

This paper discusses the relationship between cigarette smoking and the p53 protein and P21 protein expression by the immunohistochemical analysis in 93 cases with lung cancer in which squamous cell carcinoma accounted for 45 cases, adenocarcinoma 48 cases. The results showed that positive proportion of p53 protein expression was 74.20% (28 of 37 squamous cell carcinoma, 21 of 30 adenocarcinomas) in cigarette smoking group with lung cancers, and 38.46% (3 of 8 squamous cell carcinoma, 7 of 18 adenocarcinomas) in nonsmoking group with lung cancers. The difference was statistically significant. Odds ratio was 4.14 and confidence limits for OR was 1.42-12.52. A dose-related presents in the p53 protein expression for the smoking amount and smoking years. The positive proportion of P21 protein expression was 79.31% (21 of 28 squamous cell carcinoma, 25 of 30 adenocarcinomas) in cigarette smoking group with lung cancers, and 82.75% (10 of 11 squamous, 14 of 18 adenocarcinomas) in nonsmoking group with lung cancers, the difference was not statistically significant. But their positive proportion of P21 protein expression were very high in both groups. It was indicated that no relationship between cigarette smoking and the P21 protein expression. We suggest that the p53 gene could be a common target of tobacco-associated carcinogenesis in lung cancer.

Cigarette Smoking is Associated with Decreased Sperm Density

Objectives To study the association between cigarette smoking and sperm density in men of reproductive age. Methods We enrolled 224 male employees of a modern petrochemical plant in Nanjing, China. These men had no prior history of infertility or other reproductive diseases. Epidemiologic data, including information on smoking and other occupational and lifestyle exposures were obtained by a questionnaire interview. Semen specimens were collected from each participant and analyzed according to the WHO guidelines. Regression analyses were performed to estimate the effect of smoking on sperm density. Results Approximately 67% of the subjects had ever smoked cigarettes. Different measurements of smoking behavior were each associated with decreased sperm density. There was a significant dose-response trend between the tertites of total smoking amount in pack-years and sperm density. As compared to men who never smoked, current smokers had a significant reduction in sperm density (-13.3×106/ml; 95% CI, - 24. 1, -2. 5) ,while ex-smokers had only a small decrement in sperm density ( -2. 6×106/ml; 95%CI, -18. 7,13. 5). Starting smoking at less than 20 years of age was associated with significant reduction in sperm density (- 14.8×106/ml; 95% CI, - 27. 4, -2. 2). Starting smoking at 20 years or older was associated with a slightly smaller decrease ( -10.1×106/ml; 95% CI,-21.7,1.4). Conclusions Cigarette smoking is associated with decreased sperm density, showing an evident dose-response trend in this population.

Association of Cigarette Smoking with Hyperlipidemia in Male Individuals

Cigarette smoking is one of the major modifiable and environmental risk factors which can alter the lipid profile that leads to the progression of atherosclerosis and cardiovascular diseases. The aim of the current study is to explore the association of cigarette smoking with Hyperlipidemia in male individuals. A cross-sectional study was carried out from March 2017 to Au-gust 2018 in Xuzhou, Jiangsu, China. A total of 1561 male individuals were enrolled in the study with a mean age (years) of 55.33 ± 14.41. We collected data on demographic, anthropometric and lifestyle indices. Total cholesterol (TC), triglyceride (TGL), and high-density lipoprotein cholesterol (HDL-C) were determined by the enzymatic colorimetric method. The mean level of serum TC, TG, and HDL-C were 4.85 ± 0.91, 1.69 ± 1.45 and 1.27 ± 0.32 mmol/L respectively. We found that age, body mass index, pack-years, marital status, annual household income, alcohol consumption, smoking status, education level, and occupational status have significant association with Hyperlipidemia. Adjusted multiple logistic regressions showed that in old age, smoking behavior can significantly increase the risk of Hyperlipidemia. With an increase in pack-years, a significant increase is found only in TC while decreasing trend noticed in HDL-C level. Current smokers showed a significant increase in the risk of Hyperlipidemia compared to those who never smoked while smoking cessation decreases the risk of Hyperlipidemia. This study concluded that cigarette smoking along with increased age and pack-years can significantly increase the risk of Hyperlipidemia that further leads to heart diseases.

Prophylactic Anti-inflammation Inhibits Cigarette Smoke-induced Emphysema in Guinea Pigs

In this study, the effect of prophylactic anti inflammation on the development of smoke induced emphysema was investigated. Young male guinea pigs aged 1.5 - 2 months (weighing 198.3±26.9 g) were randomly divided into 4 groups: group A (cigarette smoke exposure only), group B (cigarette smoke exposure plus pentoxifylline rich (PTX, 10 mg/d) forage feeding), group C (cigarette smoke exposure plus intermittent cortical steroid injection (Triamcinolone acetonide, 3 mg, im, every three weeks) and control group (group D: animals with sham smoke exposure, raised under the same conditions). Animals in group A, B and C were exposed to smoke of cigarettes for 1 to 1.5 h twice a day, 5 days a week. All animals were killed at the 16th week and followed by morphometrical analysis of the midsagittal sectioned lung slices. Smoke exposure of 16 weeks resulted in visible emphysematous development in Group A but not in Group B and C. It was evidenced by the indicator of air space size, mean linear intercept (L m): 120.6±16.0 μm in Group A; 89.8±9.2 μm in Group B and 102.4±17.7 μm in Group C. The average L m in either group B or group C was shorter than that in Group A (ANOVA and Newman Keuls test, F=8.80, P =0.0002) but comparable to that (94.8±13.2 μm) in group D ( P >0.05). It is concluded that long term prophylactic anti inflammation inhibits pulmonary emphysema induced by cigarette smoking in the guinea pigs.

Vascular and Morphogenetic Abnormalities Associated with Exposure of Cigarette Smoke Condensate during Chicken and Murine Embryogenesis

Objective Embryonic movements （EM） and angiogenesis pathways are evolutionarily conserved mechanisms which are essential for proper embryonic development. Deviations in these processes by exposure to cigarette smoke condensate （CSC） may cause vascular and morphogenetic disorders. Methods Using chicken and mouse embryos, we have demonstrated the in vivo effects of CSC on EM, vascular development, and organogenesis. Results Examination of the CSC exposed chicken embryos revealed a significant reduction in EM, stunted growth, deviated pattern of blood vessels, hemorrhages, and localized necrosis. Likewise, mouse embryos that were exposed to CSC at E8.5 and E9.5 died between E11.5 and E12.5, respectively. These mouse embryos showed defects in morphogenesis and remodeling of the embryonic vasculature, while littermate controls showed normal development. Conclusion Cigarette smoking during pregnancy is fatal for growing embryos. CSC may induce the remodeling of embryonic vasculature, leading to various pathologies.

Effects of Puerarin on Pulmonary Vascular Remodeling and Protein Kinase C-α in Chronic Cigarette Smoke Exposure Smoke-exposed Rats

In order to investigate the effects of puerarin on pulmonary vascular remodeling and protein kinase C-α （PKC-α） in chronic exposure smoke rats, 54 male Wistar rats were randomly divided into 7 groups： control group （C group）, smoke exposure groups （S4w group, S8w group）, puerarin groups （P4w group, P8w group）, propylene glycol control groups （PC4w group, PC8w group）. Rats were exposed to cigarette smoke or air for 4 to 8 weeks. Rats in puerarin groups also received puerarin. To evaluate vascular remodeling, alpha-smooth muscle actin （α-SM-actin） staining was used to count the percentage of completely muscularised vessels to intraacinar pulmonary arteries （CMA/IAPA） which was determined by morphometric analysis of histological sections. Pulmonary artery smooth muscle cell （PASMC） apoptosis was detected by in situ end labeling technique （TUNEL）, and proliferation by proliferating cell nuclear antigen （PCNA） staining. Reverse transcription-polymerase chain reaction （RT-PCR）, immunofluorescence staining and Western blot analysis were done to detect the PKC-α mRNA and protein expression in pulmonary arteries. The results showed that in cigarette smoke-exposed rats the percentage of CMA/IAPA and α-SM-actin expression were increased greatly, PASMC apoptosis was increased and proliferation was markedly increased; Apoptosis indices （AI） and proliferation indices （PI） were higher than in C group; AI and PI were correlated with vascular remodeling indices; The expression of PKC-α mRNA and protein in pulmonary arteries was significantly higher than in C group. In rats treated with puerarin, the percentage of CMA/IAPA and cell proliferation was reduced, whereas PASMC apoptosis was increased; The expression levels of PKC-α mRNA and protein were lower than in smoke exposure rats. There was no difference among all these data between S groups and PC groups. These findings suggested that cigarette smoke-induced pulmonary vascular remodeling was most likely an effect of the imbalance of PASMC proliferation and apoptosis. Puerarin appears to be able to reduce cell proliferation and vascular remodeling possibly through PKC signaling transduction pathway.

Effect of Cigarette Smoke Extract on the Role of Protein Kinase C in the Proliferation of Passively Sensitized Human Airway Smooth Muscle Cells

To investigate the effect of cigarette smoke extract (CSE) on the role of protein kinase C (PKC) in the proliferation of passively sensitized human airway smooth muscle cells (HASMCs). After synchronization of cultured HASMCs, they were divided into a group A and Group B. The group A was treated with normal human serum and served as controls and the group B was treated with the serum of asthma patients. The group A was further divided into group of A_1, A_2 and A_3 and the group B was sub-divided into the group of B_1, B_2, B_3, B_4 and B_5. No other agents were added to the group A_1 and B_1. The cells of group A_2 and B_2 were stimulated with 5 % CSE for 24 h. HASMCs from group A_3 and B_3 were treated with PKC agonist PMA (10 nmol/L) and CSE (5 %) for 24 h. PKC inhibitor Ro-31-8220 (5 μmol/L) was added to the HASMCs of group B_4 for 24 h. The cells from group B_5 were stimulated with Ro-31-8220 (5 μmol/L) and CSE (5 %) for 24 h. The proliferation of HASMCs isolated from group A and B was examined by cell cycle analysis, MTT colorimetric assay and 3H-TdR incorporation test. The expression of PKC-α in each group was observed by Western blotting and RT-PCR, respectively. The results showed that the percentage of S phase, absorbance (A) value, the rate of 3H-TdR incorporation, the ratios of A value of PKC-α mRNA and the A value of PKC-α protein in HASMCs from group B_1, B_2 and B_3 were significantly increased compared to those of group A_1, A_2 and A_3 correspondingly and respectively (P<0.01). The proliferation of HASMCs of group A_2 and B_2 stimulated with CSE and group A_3 and B_3 stimulated with CSE and PMA were also significantly enhanced when group A_1, A_2 and A_3 and group B_1, B_2 and B_3 compared to each other (P<0.05, P<0.01, respectively). The percentage of S phase, absorbency (A) value, 3H-TdR incorporation rate, the ratios of A value of PKC-α mRNA and the A value of PKC-α protein in HASMCs from group B_4 treated with Ro-31-8220 and group B_5 treated with CSE and Ro-31-8220 were significantly decreased as compared to those of group B_1 and B_2 correspondingly and respectively (P<0.05, P<0.01). It was concluded that CSE can enhance the passively sensitized HASMC proliferation and the expression of PKC alpha. PKC and its alpha subtype may contribute to this process. Our results suggest cigarette may play an important role in ASMCs proliferation of asthma through PKC signal pathway.

Injury of Mouse Brain Mitochondria Induced by Cigarette Smoke Extract and Effect of Vitamin C on It in vitro

Objective To investigate the toxicity of cigarette smoke extract (CSE) and nicotine on mouse brain mitochondria as well as the protective effect of vitamin C in vitro. Method Mouse brain mitochondria in vitro was incubated with CSE or nicotine in the absence or presence of vitamin C for 60 minutes, and the changes of mitochondrial function and structure were measured. Results CSE inhibited mitochondrial ATPase and cytochrome C oxidase activities in a dose-dependent manner. However, no significant changes in the peroxidation indices were observed when mitochondrial respiratory enzymes activity was inhibited, and protection of mitochondria from CSE-induced injury by vitamin C was not displayed in vitro. The effect of CSE on mouse brain mitochondria swelling response to calcium stimulation was dependent on calcium concentrations. CSE inhibited swelling of mitochondria at 6.5μmol/L Ca2+, but promoted swelling response at 250μmol/L Ca2+. Nicotine, the major component of cigarette smoke, showed no significant damage in mouse brain mitochondria in vitro. The CSE treatment induced mitochondrial inner membrane damage and vacuolization of the matrix, whereas the outer mitochondrial membrane appeared to be preserved. Conclusion The toxic effect of CSE on brain mitochondria may be due to its direct action on enzymatic activity rather than through oxygen free radical injury. Nicotine is not the responsible component for the toxicity of CSE to brain mitochondria.

Roles of TGF-β Signaling Pathway in Endoplasmic Reticulum Stress in Endothelial Cells Stimulated with Cigarette Smoke Extract

To investigate the role of signaling pathway in the effect of endoplasmic reticulum stress（ER stress） in endothelial cells stimulated with cigarette smoke extract（CSE）. Human umbilical vein endothelial cells（HUVECs） were cultured and divided into 3 groups： CSE-stimulated group, CSE-stimulated with 4-PBA group, and negative control group. HUVECs were cultured and stimulated with CSE at concentrations of 5%, 10% and 20%, respectively, mR NA of CXCL-8 and GRP78 was detected by real-time PCR. ELISA was performed to test the expression of CXCL-8 protein, and neutrophils migration was detected by Transwell board test. The NF-κB, ERK, p38 MAPK and transforming growth factor beta（TGF-β） were detected by flow cytometry. The mRNA of CXCL-8 and GRP78 increased in CSE-stimulated HUVECs（P〈0.05）. Furthermore, it was concentration-dependent. 4-PBA significantly reduced the expression of CXCL-8 protein（P〈0.05） and neutrophil migration（P〈0.05）. The TGF-β, rather than the NF-κB, ERK and P38 MAPK pathway might be involved in ER stress stimulated by CSE. CSE induced neutrophils migration by increasing the expression of CXCL-8 in endothelial cells. ER stress might play a role in the effect of neutrophils migration stimulated with CSE, and TGF-β pathway may contribute to the ER stress in HUVECs.

Cigarette smoke‑induced malignant transformation via STAT3 signalling in pulmonary epithelial cells in a lung‑on‑a‑chip model

Background Chronic obstructive pulmonary disease(COPD)is a severe public health problem.Cigarette smoke(CS)is a risk factor for COPD and lung cancer.The underlying molecular mechanisms of CS-induced malignant transformation of bronchial epithelial cells remain unclear.In this study,we describe a lung-on-a-chip to explore the possible mechanistic link between cigarette smoke extract(CSE)-associated COPD and lung cancer.Methods An in vitro lung-on-a-chip model was used to simulate pulmonary epithelial cells and vascular endothelial cells with CSE.The levels of IL-6 and TNF-αwere tested as indicators of inflammation using an enzyme-linked immune sorbent assay.Apical junction complex mRNA expression was detected with qRT-PCR as the index of epithelial-to-mesenchymal transition(EMT).The effects of CSE on the phosphorylation of signal transduction and transcriptional activator 3(STAT3)were detected by Western blotting.Flow cytometry was performed to investigate the effects of this proto-oncogene on cell cycle distribution.Results Inflammation caused by CSE was achieved in a lung-on-a-chip model with a mimetic movement.CSE exposure induced the degradation of intercellular connections and triggered the EMT process.CSE exposure also activated the phosphorylation of proto-oncogene STAT3,while these effects were inhibited with HJC0152.Conclusions CSE exposure in the lung-on-a-chip model caused activation of STAT3 in epithelial cells and endothelial cells.HJC0152,an inhibitor of activated STAT3,could be a potential treatment for CS-associated COPD and lung cancer.

Parkinson's Disease and Smoking: An Integral Part of PD's Etiological Study

To explore the association of Parkinson抯 disease (PD) with cigarette smoking. Methods One hundred of fourteen PD patients were compared with 205 control subjects who were matched by gender, race and residency. A previously validated questionnaire including smoking, alcohol/tea consumption as well as some other environmental exposure data was administered. Results With never-smokers as the reference category, we observed reduced risk for PD among ever smokers (OR=0.49, 95% CI: 0.30 to 0.79) current smokers (OR=0.44, 95% CI: 0.23 to 0.86) and ex-smokers (OR=0.54, 95% CI: 0.30 to 0.96). When ever smokers were stratified by years of smoking, there was an inverse correlation between those whose smoking history was longer than 20 years (OR=0.40 95% CI: 0.21 to 0.81) and an even mild protective correlation between those who smoked less than 20 years (OR=0.57, 95% CI: 0.33 to 0.99). Those who had quitted smoking for more than 20 years were less likely to have the disease than never smokers, and those who had quitted for less than 20 years were least likely to have PD, while those who were current smokers were still least likely to have the disease. We found significant inverse gradient with pack-day smoking (trend P<0.05), and the inverse correlation between cigarette smoking and PD was not confounded by alcohol/tea consumption and other confounding bias. Conclusions The inverse correlation between Parkinson抯 disease risk and smoking as well as the trend of gradient dose response is again observed in our study. More future researches are needed to confirm these correlations and to explore further biochemical evidence.

Genotoxicity and Reduced Heat Shock Protein 70 in Human Airway Smooth Muscle Cells Exposed to Cigarette Smoke Extract

Cigarette smoke is associated with the development of several diseases, such as chronic ob- structive pulmonary disease （COPD）. The purpose of this study was to investigate genotoxicity and heat shock protein 70 （Hsp70） in human airway smooth muscle cells （HASMCs） exposed to cigarette smoke extract （CSE）. HASMCs was exposed to CSE with different doses for 24 h. The level of 8-hydroxydeoxyguanosine （8-OHdG） was determined by using HPLC-ECD, the DNA damage was ana- lyzed by using comet assay, and apoptosis was examined by using Annexin-FITC/PI staining. The pro- duction of Hsp70 after CSE stimulation was tested. Results indicated that CSE significantly increased the level of 8-OHdG, DNA damage and cell apoptosis, and reduced the production of Hsp70. In par- ticular, levels of Hsp70 were inversely correlated with 8-OHdG, DNA damage and cell apoptosis. It was concluded that cigarette smoke induced genotoxicity and decreased the production of cell protective protein Hsp70, which may contribute to the development of some airway diseases.

Assessment of tobacco heating system 2.4 on osteogenic differentiation of mesenchymal stem cells and primary human osteoblasts compared to conventional cigarettes

BACKGROUND Cigarette smoking(CS)is the most common method of consuming tobacco.Deleterious effects on bone integrity,increased incidence of fractures,and delayed fracture healing are all associated with CS.Over 150 of the 6500 molecular species contained in cigarette smoke and identified as toxic compounds are inhaled by CS and,via the bloodstream,reach the skeletal system.New technologies designed to develop a reduced-risk alternative for smokers are based on electronic nicotine delivery systems,such as e-cigarettes and tobacco heating systems(THS).THS are designed to heat tobacco instead of burning it,thereby reducing the levels of harmful toxic compounds released.AIM To examine the effects of THS on osteoprogenitor cell viability and function compared to conventional CS.METHODS Human immortalized mesenchymal stem cells(n=3)and primary human preosteoblasts isolated from cancellous bone samples from BG Unfall Klinik Tübingen(n=5)were osteogenically differentiated in vitro with aqueous extracts generated from either the THS 2.4“IQOS”or conventional“Marlboro”cigarettes for up to 21 d.Cell viability was analyzed using resazurin conversion assay(mitochondrial activity)and calcein-AM staining(esterase activity).Osteogenic differentiation and bone cell function were evaluated using alkaline phosphatase(AP)activity,while matrix formation was analyzed through alizarin red staining.Primary cilia structure was examined by acetylatedα-tubulin immunofluorescent staining.Free radical production was evaluated with 2’,7’-dichlorofluoresceindiacetate assay.RESULTS Our data clearly show that THS is significantly less toxic to bone cells than CS when analyzed by mitochondrial and esterase activity(P<0.001).No significant differences in cytotoxicity between the diverse flavors of THS were observed.Harmful effects from THS on bone cell function were observed only at very high,non-physiological concentrations.In contrast,extracts from conventional cigarettes significantly reduced the AP activity(by two-fold)and matrix mineralization(four-fold)at low concentrations.Additionally,morphologic analysis of primary cilia revealed no significant changes in the length of the organelle involved in osteogenesis of osteoprogenitor cells,nor in the number of ciliated cells following THS treatment.Assessment of free radical production demonstrated that THS induced significantly less oxidative stress than conventional CS in osteoprogenitor cells.CONCLUSIONTHS was significantly less harmful to osteoprogenitor cells during osteogenesisthan conventional CS. Additional studies are required to confirm whether THS isa better alternative for smokers to improve delays in bone healing followingfracture.

Cigarette Smoke Extract Inhibits the Proliferation of Alveolar Epithelial Cells and Augments the Expression of P21^(WAF1)

Cigarette smoking is intimately related with the development of chronic obstructive pulmonary diseases, and alveolar epithelium is a major target for the exposure of cigarette smoke extract. In order to investigate the effect of cigarette smoke extract on the proliferation of alveolar epithelial cell type Ⅱ and its relationship with P21^WAF1, the alveolar epithelial type Ⅱ cell line （A549） cells were chosen as surrogate cells to represent alveolar epithelial type Ⅱ cells. MTT assay was used to detect cell viability after interfered with different concentrations of cigarette smoke extract. It was observed cigarette smoke extract inhibited the growth of A549 cells in a dose- and time-dependent manner. The morphological changes, involving the condensation and margination of nuclear chromatin, even karyorrhexis, were observed by both Hoechst staining and electronic microscopy. Flow cytometry analysis demonstrated the increased cell percentages in G1 and subG1 phases after the cells were incubated with cigarette smoke extract. The expression of p21^WAF1 protein and mRNA was also significantly increased as detected by the methods of Western blot or reverse transcription-polymerase chain reaction respectively. In conclusion, cigarette smoke extract inhibits the proliferation of alveolar epithelial cell type Ⅱ and blocks them in G1/S phase. The intracelhilar accumulation of P21^WAF1 may be one of the mechanisms which contribute to cigarette smoke extract-induced inhibition of cell proliferation.

Involvement of TRPC1 and Cyclin D1 in Human Pulmonary Artery Smooth Muscle Cells Proliferation Induced by Cigarette Smoke Extract

Cigarette smoking contributes to the development of pulmonary artery hypertension(PAH).As the basic pathological change of PAH,pulmonary vascular remodeling is considered to be related to the abnormal proliferation of pulmonary artery smooth muscle cells(PASMCs).However,the molecular mechanism underlying this process remains not exactly clear.The aim of this research was to study the molecular mechanism of PASMCs proliferation induced by smoking.Human PASMCs(HPASMCs)were divided into 6 groups:0%(control group),cigarette smoking extract(CSE)-treated groups at concentrations of 0.5%,1%,2%,5%,10%CSE respectively.HPASMCs proliferation was observed after 24 h.HPASMCs were divided into two groups:0(control group),0.5%CSE group.The mRNA and protein expression levels of transient receptor potential channel 1(TRPC1)and cyclin D1 in HPASMCs after CSE treatment were respectively detected by RT-PCR and Western blotting.The intracellular calcium ion concentration was measured by the calcium probe in each group.In the negative control group and TRPC1-siRNA transfection group,the proliferation of HPASMCs and the expression of cyclin D1 mRNA and protein were detected.Data were compared with one-way ANOVA(for multiple-group comparison)and independent t-test(for two-group comparison)followed by the least significant difference(LSD)test with the computer software SPSS 17.0.It was found that 0.5%and 1%CSE could promote the proliferation of HPASMCs(P<0.05),and the former was more effective than the latter(P<0.05),while 3%and above CSE had inhibitory effect on HPASMCs(P<0.05).The mRNA and protein expression levels of TRPC1 and cyclin D1 in 0.5%and 1%CSE groups were significantly higher than those in the control group(P<0.05),while those in 3%CSE group were significantly decreased(P<0.05).Moreover,the proliferation of HPASMCs and the expression of cyclin D1 mRNA and protein in TRPC1-siRNA transfection group were significantly reduced as compared with those in the negative control group(P<0.05).It was concluded that low concentration of CSE can promote the proliferation of HPASMCs,while high concentrations of CSE inhibit HPASMCs proliferation.These findings suggested that CSE induced proliferation of HPASMCs at least in part via TRPC1-mediated cyclin D1 expression.