Aroclor1254预先染毒增强苯并[a]芘对Hep G2细胞DNA的损伤

目的: 探讨Hep G2细胞经Aroclor1254预处理后对苯并[a]芘诱发的DNA损伤的影响. 方法: 运用单细胞凝胶电泳技术检测了Hep G2细胞经Aroclor1254(23、46、92和184 μmol / L)单独染毒24 h和将其预处理24 h后再用苯并[a]芘染毒1 h对DNA损伤的影响. 结果: 苯并[a]芘诱发的DNA损伤随着Aroclor1254预处理的浓度增大而升高,呈明显的剂量效应关系.当Aroclor1254预处理的浓度分别为46、92和184 μmol / L时,苯并[a]芘诱发的DNA损伤与苯并[a]芘单独作用相比分别升高了8 %、16 %和160 %.184 μmol / L的Aroclor1254预处理后,苯并[a]芘诱发的DNA损伤与苯并[a]芘单独作用相比有极显著性差异(P<0.01). 结论: Aroclor1254可显著地增强苯并[a]芘在Hep G2细胞中诱导的DNA损伤,这种损伤的增强可能和Aroclor1254对Hep G2细胞CYP1A1的诱导有关.     

Aroclorl254预先染毒增强苯并[a]芘对Hep G2细胞DNA的损伤

目的 :探讨Hep G2细胞经Aroclor1254预处理后对苯并[a]芘诱发的DNA损伤的影响。 方法 :运用单细胞凝胶电泳技术检测了HepG2细胞经Aroclor1254(23、46、92和184μmol/L)单独染毒24h和将其预处理24h后再用苯并[a]芘染毒1h对DNA损伤的影响。 结果 :苯并[a]芘诱发的DNA损伤随着Aroclor1254预处理的浓度增大而升高 ,呈明显的剂量效应关系。当Aroclor1254预处理的浓度分别为46、92和184μmol/L时 ,苯并[a]芘诱发的DNA损伤与苯并[a]芘单独作用相比分别升高了8 %、16 %和160 %。184μmol/L的Aroclor1254预处理后 ,苯并[a]芘诱发的DNA损伤与苯并[a]芘单独作用相比有极显著性差异(P<0.01)。 结论 :Aroclor1254可显著地增强苯并[a]芘在HepG2细胞中诱导的DNA损伤 ,这种损伤的增强可能和Aro clor1254对Hep G2细胞CYP1A1的诱导有关。     

邻苯二甲酸二丁酯和苯并[a]芘对大鼠睾丸支持细胞波形蛋白和微管蛋白表达的影响

背景与目的： 探讨邻苯二甲酸二丁酯(di-n-butyl phthalate,DBP)和苯并[a]芘[benzo(a)pyrene,BaP]单独或联合染毒对大鼠睾丸支持细胞波形蛋白和α-微管蛋白表达的影响。 材料与方法： 分离纯化大鼠睾丸支持细胞,以1、10、100 μg/ml DBP和0.1、1、10 μg/ml BaP单独或依次联合染毒12、24、48 h后,用免疫荧光方法检测细胞中波形蛋白和α-微管蛋白的表达。 结果： 与DMSO组比较,染毒24 h后,10 μg/ml DBP与1 μg/ml BaP均可诱导波形蛋白表达水平下降(P<0.05),100 μg/ml DBP组和10 μg/ml BaP组的波形蛋白下降更为显著(P<0.01),100 μg/ml DBP＋10 μg/ml BaP联合染毒组波形蛋白的表达显著降低(P<0.01)。染毒48 h后,DBP和BaP单独染毒中、高剂量组波形蛋白的表达显著降低(分别为P<0.05和P<0.01);联合染毒各组的波形蛋白表达与DMSO组相比均显著减少(P<0.05或P<0.01),但与DBP和BaP各对应剂量单独作用组并无显著差异(P>0.05)。染毒24 h后,10 μg/ml BaP组α-微管蛋白表达明显增加(P<0.05);48 h后,100 μg/ml DBP组α-微管蛋白表达显著上升(P<0.05), BaP各组α-微管蛋白表达均显著增加。 结论： 一定剂量的DBP和/或BaP可诱导大鼠支持细胞内波形蛋白表达降低,微管蛋白表达增加,二者联合作用呈现拮抗效应。     

真菌提取物AMH的肿瘤化学预防活性组分追踪

目的：对真菌提取物AMH进行活性组分追踪,为分离其活性化学成分、开发抗癌药物提供基础。方法：采用苯并（a）芘诱发小鼠肿瘤实验,评价AMH的5个组分对苯并（a）芘诱发肿瘤的预防作用。结果：苯并（a）芘能诱导昆明种小鼠多个脏器发生肿瘤。AMH 5个组分对苯并（a）芘诱发小鼠肿瘤的作用存在明显差异,与阴性对照组相比,组分A、B、C、E具有促进肺腺瘤发生的作用（P〈0.05）;组分B和E能抑制苯并（a）芘诱导的脏器肿瘤（P〈0.05）;组分D具有抑制苯并（a）芘诱发小鼠脏器肿瘤和肺腺瘤的作用（P〈0.01）,是AMH中具有肿瘤化学预防作用的活性组分。结论：AMH组分D具有肿瘤化学预防作用,是下一步活性追踪的功效组分。     

化学诱变剂在实验海洋食物链中的流动以及遗传毒性的检测——Ⅱ.有机诱变剂苯并[a]芘

采用高压液相色谱(HPLC)测定的方法研究了有机诱变剂苯并[a]芘在实验海洋食物链(从浮游藻类褐指藻Phaeodactylum tricornutum Bohlin经中国对虾Penaeueus orientalis Kishinouye到欧氏六线鱼Hexagrammos otakii Jordan et Starks)中的流动,并对积累苯并]a[芘的中国对虾和欧氏六线鱼内脏和肌肉进行了紫露草微核(Trad-MCN)的测定,结果如下:①苯并]a[芘具有延缓褐指藻生长的作用。褐指藻中苯并[a]芘的吸着量随剂量的增大而增大。苯并[a]芯的测定量小于加入量,其损失量与剂量之间具有一定的相关性。②鱼虾内脏中积累的苯并[a]芘的浓度高于肌肉中的浓度。苯并[a]芘在中国对虾到欧氏六线鱼的传递中浓度减少,在鱼肉中很难检测到。通过显著性t测检发现,处理组和对照组虾肉之间的诱变性差异显著(P<0.05),处理组和对照组虾内脏之间的违变性差异亦显著)P<0.005)。     

ERCC2/XPD基因缺失对苯并[a]芘所致DNA损伤修复的影响

目的： 探讨核苷酸切除修复交叉互补基因2 (excision repair cross complementation group 2/Xeroderma pigmentosum D,ERCC2/XPD)在苯并[a]芘所诱导的细胞DNA损伤与修复过程中的作用。方法：应用中国仓鼠卵巢细胞系CHO野生型AA8和ERCC2表达缺失型UV5作为细胞对照模型,MTT法比较两种细胞经苯并[a]芘处理后细胞抑制率的差别;彗星试验和Rad51免疫荧光试验检测不同浓度苯并[a]芘处理及修复24 h后细胞DNA损伤修复的情况。结果：与野生型AA8细胞相比,UV5细胞对苯并[a]芘所致损伤更加敏感,细胞存活率降低 (P<0.05)。彗星试验和Rad51免疫荧光试验结果显示,UV5细胞由于缺失ERCC2/XPD基因,修复苯并[a]芘所致DNA损伤能力降低 (P<0.05)。 结论：ERCC2/XPD蛋白在核苷酸切除修复中发挥解旋作用,对苯并[a]芘所致DNA损伤修复至关重要。     

泛素连接酶RING2对苯并[a]芘染毒人支气管上皮细胞周期和P53蛋白表达的影响

目的:探讨泛素连接酶RING2对苯并[a]芘(BaP)染毒人支气管上皮16HBE细胞周期和P53蛋白表达的影响。方法:以16HBE未处理组为阴性对照组,二甲基亚砜(DMSO)组为溶剂对照组,MOCK组为序列对照组。在使用RNA干扰技术降低16HBE细胞泛素连接酶RING2基因表达前后,分别采用不同浓度BaP(1、2、4、8、16、32 μmol/L)染毒24 h;或16 μmol/L BaP染毒不同时间(1、2、4、8、12、24 h)。用流式细胞术检测干扰前后两组细胞周期分布情况,用Western-blot法检测干扰前后两组细胞P53蛋白表达水平。结果:流式细胞术检测结果显示,与阴性对照组比较,16HBE细胞染毒后各浓度和各时点组S期细胞所占的比例均增加(P<0.05),而16HBE(siRNA-RING2)各浓度和各时点组S期细胞所占的比例均下降(P<0.05)。协方差分析显示分组因素(是否进行RNAi)和染毒浓度都对S期细胞比例有影响(P均<0.01),16HBE(siRNA-RING2)细胞组的修正均数(17.09%)比16HBE细胞组(31.55%)明显降低(P<0.01)。分组因素和染毒时间都对S期细胞比例有影响(P均<0.01),16HBE(siRNA-RING2)细胞组的修正均数(13.07%)比16HBE细胞组(28.04%)明显下降(P<0.01)。Western-blot结果显示,与阴性对照组比较,16HBE 细胞染毒后各浓度和各时点组P53的表达水平均增加(P<0.05),而16HBE(siRNA-RING2)细胞除16 μmol/L染毒8 h组外,其余各组P53的表达水平均降低(P<0.05)。协方差分析显示分组因素和染毒浓度都对P53的表达水平有影响,P值分别为0.026和0.028。16HBE(siRNA-RING2)细胞组的修正均数(0.989)比16HBE细胞组(1.375)明显下降(P<0.05);分组因素 和染毒时间都对P53的表达水平有影响,P值分别为0.007和0.035。16HBE(siRNA-RING2)细胞组的修正均数(0.857)比16HBE细胞组(1.541)明显下降(P<0.05)。结论:RING2参与的组蛋白泛素化修饰可能通过影响 P53表达和细胞周期S期的变化来发挥对DNA损伤修复的调控。     

长期高剂量苯并(a)芘染毒对小鼠肺脏microRNAs表达的影响

目的:研究长期高剂量苯并(a)芘[B(a)P染毒对小鼠肺组织miRNAs表达谱的影响,探讨miRNAs在B(a)P健康损害过程中的作用。方法:40只ICR小鼠随机分为对照组和染毒组,每组20只,雌雄各半。经口灌胃给予小鼠50 mg/kg B(a)P,每周2次,持续8周,对照组同时给予等量的橄榄油,染毒结束后继续饲养8周。取肺脏组织,提取总RNA,采用SOliD高通量测序技术检测miRNAs表达谱,进行miRNAs差异表达分析,并用real time-PCR验证miRNAs表达,TargetScan,miRanda及picTar软件预测miRNAs可能调控的靶基因。结果:绝大部分miRNAs在肺组织的表达信号强度较低。与对照组相比,B(a)P染毒组小鼠肺组织中共有109个miRNAs发生差异表达,其中50个miRNAs表达上调,59个miRNAs表达下调。上调幅度最大的为7.43倍,下调幅度最大的为40.63倍。为验证测序的结果,取下调较为明显的miR-20b生行real time-PCR分析,结果显示与测序结果相一致,靶基因预测显示miR-20b可能调节与细胞增殖、周期、凋亡及肿瘤发生相关的蛋白。结论:长期高剂量B(a)P染毒可引起小鼠肺组织miRNAs表达产生特异性改变,差异表达miRNAs可能在B(a)P致机体健康损害过程中起着重要作用。     

苯并（a）芘和滴滴涕联合暴露对小鼠肝脏细胞凋亡的影响

目的：探讨不同剂量苯并（a）芘[benzo（a）pyrene,B（a）P]、滴滴涕（chlorophenothane,DDT）单独及联合暴露对小鼠肝脏细胞的毒性效应。方法：成年雌性昆明种小鼠66只,随机分为11组：分别为0.5、5、50mg/（kg·d）B（a）P染毒组,0.025、0.25、2.5mg/（kg·d）DDT染毒组,0.5mg/（kg·d）B（a）P＋0.025mg/（kg·d）DDT联合染毒组,5mg/（kg·d）B（a）P＋0.25mg/（kg·d）DDT联合染毒组,50mg/（kg·d）B（a）P＋2.5mg/（kg·d）DDT联合染毒组,空白对照组（正常饲养）和溶剂对照组（植物油处理）。染毒组用含B（a）P、DDT的食用油进行腹腔注射,每天1次,连续21d,于末次给药24h后处死小鼠。取肝脏制作冰冻切片,利用原位缺口未端标记（terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling,TUNEL）法检测肝细胞凋亡情况。结果：5和50mg/（kg·d）B（a）P染毒组小鼠肝脏细胞凋亡率显著高于对照组（P〈0.05）,且50mg/（kg·d）剂量组显著高于0.5和5mg/（kg·d）剂量组（P〈0.05）;各DDT染毒组与对照组比较,差异无统计学意义（P〉0.05）;各浓度联合染毒组小鼠肝脏细胞凋亡率均高于对照组（P〈0.01）,各联合染毒组细胞凋亡率间的差异无统计学意义（P〉0.05）,联合染毒组细胞凋亡率和相应的B（a）P染毒组比较,差异无统计学意义（P〉0.05）。结论：B（a）P的单独暴露以及与DDT的联合暴露均可导致小鼠肝脏细胞凋亡的发生,并可能引发其他毒性效应。     

真菌植物松茸提取物体外抑制卷烟焦油致突变作用

背景与目的:寻找安全有效的抗突变生物资源,为肿瘤预防和降低卷烟焦油遗传危害提供科学依据.材料与方法:采用修改的Ames试验,研究真菌植物松茸提取物AMH(Antimutagenic Herb)对卷烟焦油致突变作用的影响.结果:卷烟焦油具有移码突变致突变作用,AMH能显著性抑制卷烟焦油的致突变作用(P＜0.01),对测试菌株TA97、TA98的诱发回变菌落形成抑制率最高分别达到97.0%和96.1%,AMH可使卷烟焦油的诱发回变菌落数下降至阴性范围.AMH抑制卷烟焦油致突变作用存在明显的剂量-反应关系.结论:松茸提取物AMH对卷烟焦油致突变作用具有显著的抑制作用,AMH具有抗突变作用,在肿瘤预防和降低卷烟焦油遗传危害方面具有应用前景.     

Exceptional activity of murine glutathione transferase A1-1 against (7R,8S)-dihydroxy-(9S,10R)-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene-induced DNA damage in stably transfected cells

We have shown previously that the alpha class murine glutathione transferase (GST) isoenzyme mGSTA1-1, unlike other mammalian class alpha GSTs, is highly efficient in catalyzing the glutathione (GSH) conjugation of (7R,8S)-dihydroxy-(9S,10R)-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene [(+)-anti-BPDE], which is the ultimate carcinogenic metabolite of benzo[a]pyrene. The present studies were undertaken to determine the efficacy of mGSTA1-1 in cellular protection against (+)-anti-BPDE-induced DNA damage in HepG2 cells stably transfected with mGSTA1 cDNA. Untransfected HepG2 cells, vector-transfected HepG2 cells (HepG2-vector), and cells transfected with mGSTA4 cDNA (HepG2-mGSTA4), an alpha class murine GST isoenzyme with low (+)-anti-BPDE-GSH conjugating activity, were used as controls for comparison. Intracellular GSH conjugation of (+)-anti-BPDE was significantly higher in mGSTA1-1-overexpressing HepG2 cells (HepG2-mGSTA1) than in HepG2-vector or HepG2-mGSTA4 cells. The formation of DNA-adducts of (+)-anti-BPDE, following a 10-, 20-, or 30-min exposure to 0.1, 0.5, or 1.0 microM [3H](+)-anti-BPDE, was reduced significantly in cells transfected with mGSTA1-1 compared with HepG2-vector or untransfected HepG2 cells. Consistent with the results with purified protein, overexpression of mGSTA4-4 had no effect on (+)-anti-BPDE-induced DNA damage. The results of the present study indicated that mGSTA1-1 was exceptionally effective in affording protection against (+)-anti-BPDE-induced DNA damage in a cellular system.     

视黄酸对致癌剂苯芘环氧化及其与DNA结合的抑制作用

本文采用氚标记苯芘及体外细胞培养方法,探讨维生素A的重要衍生物视黄酸的防癌机理,发现视黄酸对前致癌剂苯芘环氧化为终致癌剂及其与BALB/c系小鼠骨髓瘤细胞DNA的结合均有显著的抑制作用(P<0.01)。     

The role of 12 cDNA-expressed human,rodent, and rabbit cytochromes P450 in the metabolism of benzo[a]pyrene and benzo[a]pyrene trans-7, 8-dihydrodiol

The potent carcinogen benzo[a]pyrene (B[a]P) and its metabolite B[a]P trans-7, 8-dihydrodiol (7, 8-diol) require metabolic activation by the microsomal cytochrome P450s (P450s) to exert several adverse biological effects, including binding to DNA, toxicity, mutagenicity, and carcinogenicity. In the study reported here, we defined the role of each of 12 individual cDNA-expressed cytochrome P450s in the metabolism of B[a]P and 7, 8-diol. Human P450s 1A1 and 1A2 were expressed in the absence or presence of epoxide hydrolase (EH) in a human lymphoblastoid cell line, and six human and five rodent and rabbit P450s were expressed from cDNA with vaccinia virus vectors in the hepatoma cell line Hep G2. B[a]P metabolism resulted in nine metabolites (three diols, three quinones, and three phenols), which were separated, identified, and quantitated by high-pressure liquid chromatography. In the human lymphoblastoid cells, human 1A1 metabolized B[a]P at a rate 4.5 times greater than that for 1A2. EH was shown to be directly involved in B[a]P activation, since increasing the amount of EH resulted in less 7-hydroxybenzo[a]pyrene and more 7, 8-diol formation. Of the human P450s expressed with the vaccinia virus vectors in Hep G2 cells, 1A2 and 2C9 showed the highest activity and 2B6 showed moderate activity for B[a]P metabolism. Mouse 1A1 had activity 40 times higher than any human, rabbit, or rodent P450s, indicating the potential pitfalls of extrapolating P450 activity across species. Metabolism of the 7, 8-diol resulted in six metabolites (four tetrols and two triols). In the lymphoblastoid cells, human 1A1 was shown to be 4.2 times more active than 1A2 for 7, 8-diol metabolism. Among human P450s expressed from vaccinia virus, 1A2, 2E1, and 2C9 gave the highest activity, and 2C8 and 3A4 showed moderate activity for 7, 8-diol metabolism to the diol epoxides. Again, mouse 1A1 was much more active than any other P450. These studies, in which we determined the capacity of individual P450 in the metabolism and activation of B[a]P and 7, 8-diol, may thus lead to a better understanding of how P450s control the detoxification and activation of polycyclic aromatic hydrocarbons. © 1994 Wiley-Liss, Inc.     

Polycyclic aromatic hydrocarbons as a potential source of carcinogenicity of mate

Drinking mate, an infusion of the herb ilex paraguariensis, is very common in several South American countries, and has been associated with an increased risk of esophageal cancer. This increased risk may be attributed to drinking mate very hot, or to mate’s potentially carcinogenic contaminants, such as polycyclic aromatic hydrocarbons (PAHs). Mate leaves are often dried via smoking, and therefore commercial samples may have high amounts of PAHs. We found 10 original articles that had measured PAHs in commercial dry samples, and nearly all found very high mass fractions. Most studies found benzo[a]pyrene mass fractions to be over 25?ng/g, and some found levels up to 600?ng/g. However, carcinogenic PAHs are often hydrophobic, and may not readily transfer into infusions. Seven articles studied transfer rates, and these rates varied from 1 to 50%, depending on the methods employed. Further careful studies of transfer rates in situations that mimic real life drinking of mate are recommended. Also, further studies of biological indicators of PAH exposure, particularly in randomized experiments, and analyzing DNA from tumor samples of mate drinkers are recommended.     

Inhibitory effect of Phenethyl Isothiocyanate Against Benzo[a] Pyrene-Induced Rise in CYP1A1 mRNA and Apoprotein Levels as its Chemopreventive Properties

Background: Phenethyl isothiocyanate (PEITC), the most comprehensively studied aromatic isothiocyanate,has been shown to act as an anti-cancer agent mainly through modulation of biotransformation enzymesresponsible for metabolizing carcinogens in the human body. Humans are often exposed to carcinogenic factors,some of which through the diet, such as polycyclic aromatic hydrocarbon benzo[a]pyrene via the consumptionof over-cooked meats. Inhibition of the enzymes responsible for the bioactivation of this carcinogen, for exampleCYP1A1, the major enzyme required for polycyclic aromatic hydrocarbons (PAHs) bioactivation, is recognizedas a chemoprevention strategy. Objective: To evaluate the inhibitory effects of PEITC against benzo[a]pyreneinducedrise in rat liver CYP1A1 mRNA and apoprotein levels. Materials and Methods: Precision cut rat liverslices were treated with benzo[a]pyrene at 1 and 5 μM in the presence of PEITC (1-25 μM) for 24 hours, followedby determination of CYP1A1 mRNA and apoprotein levels using quantitative polymerase chain reaction andimmunoblotting. Results: Findings revealed that PEITC inhibited benzo[a]pyrene-induced rise in rat liverCYP1A1 mRNA in a dose-dependent manner as well as the apoprotein levels of CYP1A. Conclusions: It wasdemonstrated that PEITC can directly inhibit the bioactivation of benzo[a]pyrene, indicating chemopreventivepotential.     

苯并(a)芘对褐菖肝脏DNA损伤与抗氧活性的影响

背景与目的:研究苯并(a)芘BaP对褐菖鲉的毒性效应.材料与方法:将褐菖纳分别暴露于不同浓度(10、100、1 000 ng/L)的苯并(a)芘,0、7、25和50 d以及恢复期7、20 d取鱼肝脏,测定超氧化物歧化酶(SOD)、谷胱甘肽硫转移酶(GST)活性,还原型谷胱甘肽(GSH)含量和DNA单链断裂指标.实验同设溶剂对照组.结果:总SOD活性在Bap暴露7 d后被抑制,25 d后,10 ng/L和100ng/L Bap组SOD活性升高(P<0.05);50 d时,1 000 ng/L组SOD活性显著升高(P<0.05).10 ng/L BaP暴露7 d以及100 ng/L和1 000 ng/L BaP暴露50 d时,GSH含量显著增加(P<0.05).而GST活性在100 ng/L和1 000 ng/L BaP分别暴露25 d、50 d时显著增加,随着暴露时间的延长和暴露浓度的增加,各BaP浓度组DNA损伤呈加重趋势.结论:褐菖鲉肝脏SOD、GST酶活性与GSH含量结合使用以及DNA单链断裂损伤可以作为监测海洋环境中多环芳烃(PAHs)污染的潜在生物标志物.     

BaP诱导细胞恶性转化过程中DNA甲基化水平的变化

目的：通过分析苯并芘（BaP）诱导细胞恶性转化过程中DNA甲基化水平的变化,探讨BaP致癌的作用机制。方法：以正常人支气管上皮细胞（16HBE）为研究对象,使用梯度浓度BaP（0、10、20和40 μmol/L）染毒处理,构建不同染毒周期（1周、9周和15周）的细胞株,使用5-甲基胞嘧啶（5-mC）细胞免疫荧光检测各组细胞基因组DNA整体甲基化水平的变化,并进一步利用Western blotting和实时荧光定量-PCR技术分析不同染毒周期细胞甲基化蛋白酶（DNMT1、DNMT3a、DNMT3b、MBD2）表达的变化。结果：BaP染毒后,16HBE细胞的5-mC荧光强度表达下降,且随着染毒剂量的增加和染毒时间的延长,这种下降趋势更明显,其中40 μmol/L BaP染毒处理细胞15周时,肉眼已难以观察到可见荧光。与对照组比较,BaP染毒可下调细胞DNMT1蛋白及其mRNA的表达,并呈现明显的剂量和时间反应关系（P均 < 0.05）,但DNMT3a、DNMT3b、MBD2蛋白的表达变化不明显（P均 > 0.05）。结论：BaP可诱导16HBE细胞基因组DNA整体甲基化水平下调,DNMT1在其中可能发挥重要作用。     

Induction of epithelial-mesenchymal transition-related genes by benzo[a]pyrene in lung cancer cells

BACKGROUND: It is believed that epithelial-mesenchymal transition (EMT) occurs during the development and progression of cancer; however, the correlation between tobacco smoking and EMT remains to be elucidated. METHODS: Cells from the bronchioloalveolar carcinoma cell line A549 were exposed to benzo(a)pyrene (B[a]P) for 24 weeks, and morphology, proliferative activity, and gene expression profiles were analyzed. RESULTS: Although no apparent morphologic changes were observed, the B[a]P-exposed A549 cells exhibited enhanced proliferative activity in 1% bovine serum that contained medium, and dramatic changes in expression levels were observed in a large number of genes. Of those, the expression of EMT-related genes, such as migration-stimulating factor, plasminogen activator inhibitor-1, fibronectin, twist, transforming growth factor-beta2, basic fibroblast growth factor, and electron transport system, were up-regulated; whereas gene expression of E-cadherin was decreased. Most enhanced expression levels remained 8 weeks after the retrieval of B[a]P in culture. CONCLUSIONS: The current results indicated that B[a]P seems to induce EMT in lung cancer cells, and it also may drive disease progression in patients with lung cancer.     

Benzo[a]pyrene promotes proliferation of human lung cancer cells by accelerating the epidermal growth factor receptor signaling pathway

Smoking is an independent prognostic factor of lung adenocarcinoma. Benzo[a]pyrene (B[a]P) is one of the strongest carcinogens and it is present in both the environment and cigarette smoke. In this study, the effect of B[a]P on the proliferative activity of lung adenocarcinoma cells was investigated. A lung adenocarcinoma cell line, A549, was cultured with B[a]P for various periods, and its proliferative activity was examined by an MTS assay. To investigate the intracellular events related to the proliferative activity, the gene expression profile was investigated by a microarray analysis and a quantitative RT-PCR, and the protein expression and activation status of Akt, ERK 1/2 and the epidermal growth factor receptor (EGFR) were examined by a western blot analysis. Following the culture with B[a]P for 24 weeks, the serum-independent proliferative activity was increased. A microarray analysis revealed that a reversible upregulation of the EGFR and epiregulin genes was recognized in the B[a]P treated cells, in which the overexpression of the phosphorylated EGFR protein was also recognized. The EGFR tyrosine kinase inhibitor reduced the cellular proliferation and the level of phosphorylation of ERK1/2, which is a downstream signal of the EGFR, in the B[a]P-treated A549 cells. Moreover, the B[a]P treatment increased the mRNA expressions of the ligands for EGFR such as amphiregulin and epiregulin. B[a]P increases the proliferative potential of lung adenocarcinoma cells through the EGFR signaling pathway.