Adenovirus-mediated expression of UHRF1 reduces the radiosensitivity of cervical cancer HeLa cells to γ-irradiation

Aim:

An in vitro study was carried out to determine the effect of UHRF1 overexpression on radiosensitivity in human cervical cancer HeLa cells using adenovirus-mediated UHRF1 gene transfer (Ad5-UHRF1).

Methods:

Cell survival was evaluated using the clonogenic survival assay and the MTT assay; apoptosis and cell cycle distribution were monitored by flow cytometry. Protein levels were measured by Western blotting. Silencing XRCC4 expression was performed by transfection of small interfering RNA (siRNA).

Results:

Increased expression of UHRF1 by Ad5-UHRF1 significantly reduced the radiosensitivity of HeLa cells. The UHRF1-mediated radioresistance was correlated with increased DNA repair capability and increased expression of the DNA damage repair protein, XRCC4. Knocking down XRCC4 expression in the cells using XRCC4 siRNA markedly reduced the UHRF1-mediated radioresistance.

Conclusion:

These results provide the first evidence for revealing a functional role of UHRF1 in human cervical cancer cells as a negative regulator of radiosensitivity.     

Icotinib enhances lung cancer cell radiosensitivity in vitro and in vivo by inhibiting MAPK/ERK and AKT activation

Icotinib hydrochloride is a small epidermal growth factor receptor‐tyrosine kinase inhibitor (EGFR‐TKI) that was developed by Chinese scientists. While clinical trials have revealed its efficacy in the treatment of lung cancer, very little is known about its role in enhancing radiosensitivity. In this study, we investigated the effectiveness of Icotinib in enhancing lung cancer cell radiosensitivity and have detailed its underlying molecular mechanism. The lung cancer cell line H1650 was pretreated with or without Icotinib for 24 hours before radiation, and clonogenic survival assay was performed. Cell apoptosis was also analyzed by flow cytometry, while western blotting was performed to examine the activation of EGFR and its downstream kinases in H1650 cells after Icotinib and radiation treatment. Furthermore, a xenograft animal model was established to evaluate the radiosensitivity of Icotinib in vivo and to confirm its mechanism. Our results demonstrate that pretreatment with Icotinib reduced clonogenic survival after radiation, inhibited EGFR activation, and increased radiation‐induced apoptosis in H1650 cells. The phosphorylation of protein kinase B (AKT), extracellular regulated protein kinase 1/2 (ERK1/2), and EGFR was inhibited after Icotinib and radiation combination treatment in vitro and in vivo compared with individual treatments. Combination treatment also affected the expression of the DNA repair protein H2A histone family member X (γ‐H2AX). In conclusion, our results reveal that Icotinib enhances radiosensitivity in lung cancers in vitro and in vivo and the mechanism of this may involve blocking the EGFR‐AKT and MAPK‐ERK pathways and limiting DNA repair.     

Correlativity study between expression of DNA double-strand break repair protein and radiosensitivity of tumor cells

DNA double-strand break (DSB) is generally regarded as the most lethal of all DNA lesions after radiation. Ku80, DNA-PK catalytic subunit (DNA-PKcs) and ataxia telangiectasia mutated (ATM) proteins are major DSB repair proteins. In this study, survival fraction at 2Gy (SF2) values of eight human tumor cell lines (including four human cervical carcinoma cell lines HeLa, SiHa, C33A, Caski, three human breast carcinoma cell lines MCF-7, MDA-MB-231, MDA-MB-453, and one human lung carcinoma cell line A549) were acquired by clone formation assay, and western blot was applied to detect the expressions of Ku80, DNA-PKcs and ATM protein. The correlativity of protein expression with SF2 value was analyzed by Pearson linear correlation analysis. We found that the expression of the same protein in different cell lines and the expression of three proteins in the same cell line had a significant difference. The SF2 values were also different in eight tumor cell lines and there was a positive correlativity between the expression of DNA-PKcs and SF2 (r =0.723, P = 0.043), but Ku80 and ATM expression had no correlation with SF2 (P > 0.05). These findings suggest that the expression level of DNAPKcs protein can be an indicator for predicting the radiosensitivity of tumor cells.     

AC480, formerly BMS-599626, a pan Her inhibitor,enhances radiosensitivity and radioresponse of head and neck squamous cell carcinoma cells in vitro and in vivo

Purpose: The present study investigated the effect of AC480, a small molecule pan-HER tyrosine kinase inhibitor, on in vitro radiosensitivity and in vivo radioresponse of a human head and neck squamous cell carcinoma cell line. Methods: HN-5 cells were exposed to γ-radiation with and without AC480 and assayed for proliferation, clonogenic survival, apoptosis, cell cycle distribution, and DNA damage. The cells were analyzed by immunoprecipitation and western blotting for proteins involved in apoptosis, cell cycle regulation, and the EGFR pathway. The effect of AC480 on tumor radioresponse was assessed by tumor growth delay assay using HN5 tumor xenografts generated in nude mice. Results: At the molecular level, in HN-5 cells the agent inhibited the expression of pEGFR, pHER2, cyclins D and E, pRb, pAkt, pMAPK, pCDK1 and 2, CDK 6, and Ku70 proteins. The drug also induced accumulation of cells in the G1 cell cycle phase, inhibited cell growth, enhanced radiosensitivity, and prolonged the presence of γ-H₂AX foci up to 24 h after radiation. AC480 did not increase the percentage of cells undergoing radiation-induced apoptosis. The drug given before and during irradiation improved the radioresponse of HN5 tumors in vivo. Conclusion: AC480 significantly enhanced the radiosensitivity of HN-5 cells, expressing both EGFR and Her2. The mechanisms involved in the enhancement included cell cycle redistribution and inhibition of DNA repair. Both in vitro and in vivo data from our study suggest that AC480 has potential to increase tumor response to radiotherapy.     

γH2AX对肺癌放射敏感性的预测效果*

【摘要】目的 探讨人肺癌细胞受照后γH2AX表达量变化与肺癌细胞放射敏感性之间的关系。方法 选择肺腺癌A549和小细胞肺癌SBC-3细胞株,采用细胞克隆形成实验检测经不同剂量（0、2、4、6、8、10Gy）照射后A549 和SBC-3细胞的克隆形成率,并绘制细胞生存曲线;应用Western blot检测经2Gy放射剂量照射后不同时间点（0 min、30min、1h、2h、6h、12h、24h、36h、48h）的细胞中γH2AX蛋白表达量。分析γH2AX蛋白表达量变化与肿瘤细胞放射敏感性的相关性。结果 小细胞肺癌SBC-3细胞的放射敏感性明显高于肺腺癌A549细胞。两种细胞受照后1h和6h,γH2AX的表达量均与肿瘤细胞的平均致死剂量（D0）相关。结论 γH2AX可以作为肺癌细胞放射敏感性的一个预测指标。     

Nuclear loss of DNA repair Ku proteins and c-myc expression in apoptosis of cerulein-stimulated pancreatic acinar cells

Cerulein induces oxidative stress and an acute, edematous form of pancreatitis. Cell death linked to oxidative DNA damage has been implicated in acute pancreatitis. During DNA damage, DNA repair proteins, Ku70 and Ku80, prevent cell death but severe DNA damage triggers apoptosis. This study aims to investigate the role of Ku70 and Ku80 on apoptotic cell death, induced by cerulein in pancreatic acinar AR42J cells. We examined Ku expression, Ku-DNA binding activity, cell viability and mRNA expression of c-myc of the cells stimulated with cerulein. As a result, cerulein induced decrease in nuclear Ku70 and Ku80 with increase in cytoplasmic Ku proteins. Cerulein decreased Ku-DNA binding activity in parallel with increase in cell death and mRNA expression of c-myc. Conclusively, nuclear loss of Ku70 and Ku80 may cause the loss of defense against DNA damage and apoptosis in pancreatic acinar cells stimulated with cerulein. Received 9 October 2006; accepted 16 November 2006     

Increase the cisplatin cytotoxicity and cisplatin-induced DNA damage in HepG2 cells by XRCC1 abrogation related mechanisms

Cisplatin is one of the most potent chemotherapeutic anticancer drugs for the treatment of various cancers. The cytotoxic action of the drug is often thought to be associated with its ability to bind DNA to form cisplatin–DNA adducts. Impaired DNA repair processes including base excision repair (BER) play important roles on its cytotoxicity. XRCC1 is a key protein known to play a central role at an early stage in the BER pathway. However, whether XRCC1 contributes to decrease the cisplatin cytotoxicity and cisplatin-induced DNA damage in HepG2 still remains unknown. Hence, the purpose of this study was to explore whether abrogation of XRCC1 gene expression by short hairpin RNAs (shRNA) could reduce DNA repair and thus sensitize liver cancer cells to cisplatin. We abrogated the XRCC1 gene in HepG2 cell using shRNA transfection. Cell viability was measured by MTT assay and clonogenicity assay. Comet assay was used to detect the DNA damage induced by cisplatin. The host cell reactivation was employed to assess the DNA repair capacity of cisplatin-damaged luciferase reporter plasmid. Flow cytometry analysis was used to determine cisplatin-induced apoptosis, cell cycle and reactive oxygen species (ROS). The results showed that abrogation of XRCC1 could sensitize HepG2 cells to cisplatin. This enhanced cytotoxicity could be attributed to the increased DNA damage and reduced DNA repair capacity. Increasing cell cycle arrest and intracellular ROS production lead to more tumor cell apoptosis and then enhanced the cisplatin cytotoxicity. Our results suggested that the cisplatin cytotoxicity may increase by targeting inhibition of XRCC1.     

野马追总黄酮的体内外抗乳腺癌活性及机制研究

目的 探究野马追总黄酮(TFE)的体内外抗乳腺癌活性及相关的作用机制。方法 MTT法检测TFE对乳腺癌细胞(MCF-7、T47D、MDA-MB-231、MDA-MB-468)和人正常乳腺上皮细胞MCF-10A增殖的影响;流式细胞术检测TFE对乳腺癌细胞周期和凋亡的影响;吖啶橙(AO)染色法检测TFE对细胞自噬的影响;Western blot检测细胞周期、凋亡、自噬相关蛋白的变化,以及PI3K/Akt信号通路相关蛋白的变化;建立MDA-MB-231细胞的裸鼠移植瘤模型,观察TFE的体内抗肿瘤活性。结果 TFE能明显抑制乳腺癌细胞增殖,并呈剂量依赖性,而对人正常乳腺上皮细胞无显著的抑制作用;TFE能增加G₂/M期细胞比例,上调p-cdc-2蛋白表达,下调cdc-2和Cyclin B1蛋白表达;TFE能显著增加乳腺癌细胞凋亡比例,上调促凋亡蛋白Bad和Bax表达,下调抗凋亡蛋白Bcl-2表达;TFV能够诱导乳腺癌细胞产生自噬,自噬相关蛋白LC3-II表达上升,p62表达降低;TFE能够抑制显著抑制PI3K和Akt的磷酸化水平;TFE能够在体内抑制裸鼠肿瘤的体积。结论 TFE通过抑制PI3K/Akt信号通路,阻滞细胞周期、诱导凋亡和自噬,进而在体内外抑制乳腺癌细胞的生长。     

HER-2癌基因反义寡脱氧核苷酸对乳腺癌细胞放射敏感性的影响

目的探讨癌基因HER-2反义寡核苷酸联合放疗对乳腺癌细胞的影响。方法实验分组如下:HER-2反义寡脱氧核苷酸组、HER-2正义寡脱氧核苷酸组、叶酸对照组和空白对照组。用RT-PCR方法、MTT法及平板克隆形成实验检测乳腺癌细胞SK-Br-3受药物处理后,经60Coγ射线照射,HER-2表达水平、细胞存活分数和集落形成率的改变。结果经HER-2反义寡核苷酸-叶酸处理的细胞,对60Coγ射线的放射敏感性增加,细胞的HER-2癌基因表达水平降低,存活分数及集落形成率与正义寡核苷酸、叶酸和空白对照组比较明显降低(P<0.05),而正义寡核苷酸、叶酸与空白对照组相比无明显差异(P>0.05)。结论HER-2反义寡核苷酸抑制癌基因表达的作用增加乳腺癌细胞SK-Br-3对放疗的敏感性。     

Arsenite-induced alterations in Ku70-deficient cells: a model to study genotoxic effects

As one of three subunits of DNA-dependent protein kinase (DNA-PK), Ku70 protein plays an important role in repair of DNA double-strand breaks (DNA DSB). To further understand the functions of Ku70 protein and the mechanisms underlying arsenite-induced genotoxic effects, the effects of Ku70 deficiency were examined. The Ku70-deficient cell line HLFK and null vector cell line HLFC were established after recombinant plasmid of Ku70 gene antisense RNA and null pEGFP-C1 vector were transferred into human embryo lung fibroblasts (HLF) cells. Experiments were undertaken to detect DNA DSB damage by neutral single-cell gel electrophoresis assay (SCGE), chromosomal alterations by micronucleus test, and cell cycle progression by flow cytometry in HLFC and HLFK cells treated with control, 1, 2.5, 5, or 10 microM sodium arsenite for 2, 4, or 24 h, respectively. Western blot analysis results showed that Ku70 protein content in HLFK cells decreased to 38% of those in HLFC cells. The median lethal concentrations (LC50) of sodium arsenite to HLFC and HLFK cells for 24 h were 27.38 microM and 21.80 microM, respectively. Results of neutral SCGE assay showed that there were concentration-dependent increases in tail length of DNA DSB, in percent of cells with DNA DSB tails, and in severity of DNA DSB damage in HLFK and HLFC cells. The increases in these indices in HLFK cells were significantly higher than those found in HLFC cells exposed to similar amounts of metal. The ability of DNA DSB to repair in HLFK cells was less than that seen in HLFC cells. Sodium arsenite produced concentration-dependent elevation in micronuclei and abnormal nuclei formation. The Ku70-deficiency enhanced the susceptibility to chromosomal alterations induced by sodium arsenite. Low concentrations of sodium arsenite induced cell arrest at G1; however, at high concentrations of metal this G1 arrest effect disappeared. These results suggested that Ku70 protein plays an important role in repair of DNA DSB damage and for maintainance of genome stability.     

NVP-BEZ235, a novel dual PI3K/mTOR inhibitor,enhances the radiosensitivity of human glioma stem cells in vitro

Aim:

NVP-BEZ235 is a novel dual PI3K/mTOR inhibitor and shows dramatic effects on gliomas. The aim of this study was to investigate the effects of NVP-BEZ235 on the radiosensitivity and autophagy of glioma stem cells (GSCs) in vitro.

Methods:

Human GSCs (SU-2) were tested. The cell viability and survival from ionizing radiation (IR) were evaluated using MTT and clonogenic survival assay, respectively. Immunofluorescence assays were used to identify the formation of autophagosomes. The apoptotic cells were quantified with annexin V-FITC/PI staining and flow cytometry, and observed using Hoechst 33258 staining and fluorescence microscope. Western blot analysis was used to analyze the expression levels of proteins. Cell cycle status was determined by measuring DNA content after staining with PI. DNA repair in the cells was assessed using a comet assay.

Results:

Treatment of SU-2 cells with NVP-BEZ235 (10–320 nmol/L) alone suppressed the cell growth in a concentration-dependent manner. A low concentration of NVP-BEZ235 (10 nmol/L) significantly increased the radiation sensitivity of SU-2 cells, which could be blocked by co-treatment with 3-MA (50 μmol/L). In NVP-BEZ235-treated SU-2 cells, more punctate patterns of microtubule-associated protein LC3 immunoreactivity was observed, and the level of membrane-bound LC3-II was significantly increased. A combination of IR with NVP-BEZ235 significantly increased the apoptosis of SU-2 cells, as shown in the increased levels of BID, Bax, and active caspase-3, and decreased level of Bcl-2. Furthermore, the combination of IR with NVP-BEZ235 led to G₁ cell cycle arrest. Moreover, NVP-BEZ235 significantly attenuated the repair of IR-induced DNA damage as reflected by the tail length of the comet.

Conclusion:

NVP-BEZ235 increases the radiosensitivity of GSCs in vitro by activating autophagy that is associated with synergistic increase of apoptosis and cell-cycle arrest and decrease of DNA repair capacity.     

Role of autophagy in chemoresistance: regulation of the ATM-mediated DNA-damage signaling pathway through activation of DNA-PKcs and PARP-1

Capsaicin treatment was previously reported to reduce the sensitivity of breast cancer cells, but not normal MCF10A cells, to apoptosis. The present study shows that autophagy is involved in cellular resistance to genotoxic stress, through DNA repair. Capsaicin treatment of MCF-7 cells induced S-phase arrest and autophagy through the AMPKα-mTOR signaling pathway and the accumulation of p53 in the nucleus and cytosol, including a change in mitochondrial membrane potential. Capsaicin treatment also activated δ-H2AX, ataxia telangiectasia mutated (ATM), DNA-dependent protein kinase catalytic subunit (DNA-PKcs), and poly(ADP-ribose) polymerase (PARP)-1. Genetic or pharmacological disruption of autophagy attenuated capsaicin-induced phospho-ATM and phospho-DNA-PKcs and enhanced apoptotic cell death. ATM inhibitors, including Ku55933 and caffeine, and the genetic or pharmacological inhibition of p53 prevented capsaicin-induced DNA-PKcs phosphorylation and stimulated PARP-1 cleavage, but had no effect on microtubule-associated protein light chain 3 (LC3)-II levels. Ly294002, a DNA-PKcs inhibitor, boosted the capsaicin-induced cleavage of PARP-1. In M059K cells, but not M059J cells, capsaicin induced ATM and DNA-PKcs phosphorylation, p53 accumulation, and the stimulation of LC3II production, all of which were attenuated by knockdown of the autophagy-related gene atg5. Ku55933 attenuated capsaicin-induced phospho-DNA-PKcs, but not LC3II, in M059K cells. In human breast tumors, but not in normal tissues, AMPKα, ATM, DNA-PKcs, and PARP-1 were activated and LC3II was induced. The induction of autophagy by genotoxic stress likely contributes to the sustained survival of breast cancer cells through DNA repair regulated by ATM-mediated activation of DNA-PKcs and PARP-1.     

Allitridi induces apoptosis by affecting Bcl-2 expression and caspase-3 activity in human gastric cancer cells

INTRODUCTION Gastric cancer is the second leading cause of can-cer mortality in the world and is the leading cause ofcancer mortality in China[1]. Numerous epidemiologicalinvestigations have demonstrated that an inverse corre-lation between gastric cancer incidence and garlic con-sumption[2-8]. For example, Linqu County has gastriccancer rate that was 15 times higher than that of Cang-shan County in Shangdong Province[10], and the deathrate of gastric cancer in Linqu County was 7…     

新木脂素VB1 对宫颈癌HeLa 细胞凋亡的影响

目的探讨新木脂素即6-羟基-4-(4-羟基-3-甲氧基苯基)3-羟甲基-5-甲氧基-3,4-二氢(3R,4S)-2-醛基萘(VB1)诱导人宫颈癌HeLa细胞凋亡的作用和机制。方法体外培养HeLa细胞,碘化丙啶(PI)染色后,用流式细胞术(FCM)分析细胞的凋亡率;酶联免疫吸附法(ELISA)测定细胞组蛋白/DNA碎片水平;Westernblot检测细胞内Mcl-1蛋白的表达。结果 VB1以浓度依赖性方式增加HeLa细胞的凋亡率和细胞内组蛋白/DNA碎片水平(P<0.05),同时降低HeLa细胞内Mcl-1蛋白的表达。结论 VB1可以浓度依赖的方式诱导宫颈癌HeLa细胞的凋亡,这种作用可能与其下调细胞内Mcl-1蛋白的表达有关。     

黄芩素对miR-183/Kif2a介导乳腺癌细胞增殖和凋亡的机制研究

目的探讨黄芩素对miR-183/Kif2a介导的乳腺癌MDA-MB-231细胞增殖和凋亡的作用及可能机制。方法噻唑蓝(methylthiazolyldiphenyl-tetrazolium bromide,MTT)法检测黄芩素对乳腺癌细胞增殖活性的影响,实时荧光定量聚合酶链式反应法检测细胞中miR-183和Kif2a信使RNA的表达,在线靶基因预测软件预测miR-183和Kif2a的靶向关系。转染miR-183抑制剂和pcDNA 3.1-Kif2a,黄芩素处理细胞后,MTT法检测细胞增殖活性,流式细胞术测定细胞凋亡,蛋白质免疫印记技术(western blot,WB)检测细胞中G1/S-特异性周期蛋白-D1(Cyclin D1)、p21、半胱氨酸天冬氨酸蛋白酶3(C-Caspase-3)及半胱氨酸天冬氨酸蛋白酶9(C-Caspase-9)蛋白表达。结果经黄芩素处理后的乳腺癌细胞增殖能力下降(P<0.05),细胞中miR-183水平升高(P<0.05),Kif2a信使RNA水平降低(P<0.05)。miR-183靶向结合Kif2a并负向调控Kif2a的表达(P<0.05)。miR-183抑制剂或pcDNA 3.1-Kif2a转染可以逆转黄芩素对乳腺癌增殖、凋亡以及C-Caspase-3、C-Caspase-9、Cyclin D1、p21蛋白表达的作用。结论黄芩素通过miR-183/Kif2a调控乳腺癌细胞增殖和凋亡。     

P53-mediated cell cycle arrest and apoptosis through a caspase-3- independent, but caspase-9-dependent pathway in oridonin-treated MCF-7 human breast cancer cells

Aim： To study the caspase-3-independent mechanisms in oridonin-induced MCF-7 human breast cancer cell apoptosis in vitro. Methods： The viability of oridonin- treated MCF-7 cells was measured by MTT （thiazole blue） assay. Apoptotic cells with condensed nuclei were visualized by phase contrast microscopy. Nucleosomal DNA fragmentation was assayed by agarose gel electrophoresis. The apoptotic ratio was determined by lactate dehydrogenase assay. Cell cycle alternation and mitochondrial membrane potential were measured by flow cytometric analysis. Bax, Bcl-2, caspase-3, caspase-9, heat shock protein （Hsp）90, p53, p-p53, p21, Poly （ADP-ribose） polymerase （PARP）, and the inhibitor of caspase-activated DNase （ICAD） protein expressions were detected by Western blot analysis. Results： Oridonin inhibited cell growth in a time- and dose-dependent manner. Cell cycle was altered through the upregulation of p53 and p21 protein expressions. Pancaspase inhibitor Z-VAD-fmk and calpain inhibitor II both decreased cell death ratio. Nucleosomal DNA fragmentation and the downregulation of △ψmit were detected in oridonin-induced MCF-7 cell apoptosis, which was involved in a postmitochondrial caspase-9-dependent pathway. Decreased Bcl-2 and Hsp90 expression levels and increased Bax and p21 expression levels were positively correlated with elevated levels of phosphorylated p53 phosphorylation. Moreover, PARP was partially cleaved by calpain rather than by capase-3. Condusion： DNA damage provoked alternations in the mitochondrial and caspase-9 pathways as well as p53-mediated cell cycle arrest, but was not related to caspase-3 activity in oridonin-induced MCF-7 cells.     

Luteolin induced DNA damage leading to human lung squamous carcinoma CH27 cell apoptosis

Luteolin is an active compound from the Lonicera japonica (Caprifoliaceae). Luteolin (50 microM)-induced human lung carcinoma CH27 cell apoptosis is a typical apoptosis that was accompanied by a significant DNA condensation and apoptotic body formation. Luteolin-induced apoptosis is related to its ability to change the expression of apoptotic markers, such as caspase-3 (caspase-dependent) and apoptosis-inducing factor (caspase-independent) protein expression. The alkaline microgel electrophoresis technique (comet assay), which is the most sensitive, was used for estimation of the luteolin-induced DNA single strand breaks in this study. DNA-damaging effects of luteolin on DNA single strand breaks have been demonstrated in our study. In this study, luteolin induced S-phase cell cycle arrest and increased the mRNA of DNA repair enzymes such as human MutT homologue, 8-oxoguanine-glycosylase and apurinic endonuclease. Our data suggested that luteolin induces CH27 cell apoptosis by caspase-dependent and -independent pathway and the effect of luteolin on apoptosis of CH27 cells is associated with DNA damage and the expression of DNA repair enzymes.     

Bisdemethoxycurcumin induces DNA damage and inhibits DNA repair associated protein expressions in NCI‐H460 human lung cancer cells

Nonsmall cell lung carcinoma (NSCLC) is a devastating primary lung tumor resistant to conventional therapies. Bisdemethoxycurcumin (BDMC) is one of curcumin derivate from Turmeric and has been shown to induce NSCLC cell death. Although there is one report to show BDMC induced DNA double strand breaks, however, no available information to show BDMC induced DNA damage action with inhibited DNA repair protein in lung cancer cells in detail. In this study, we tested BDMC‐induced DNA damage and condensation in NCI‐H460 cells by using Comet assay and DAPI staining examinations, respectively and we found BDMC induced DNA damage and condension. Western blotting was used to examine the effects of BDMC on protein expression associated with DNA damage and repair and results indicated that BDMC suppressed the protein levels associated with DNA damage and repair, such as 14‐3‐3σ (an important checkpoint keeper of DDR), O6‐methylguanine‐DNA methyltransferase, DNA repair proteins breast cancer 1, early onset, mediator of DNA damage checkpoint 1 but activate phosphorylated p53 and p‐H2A.X (phospho Ser140) in NCI‐H460 cells. Confocal laser systems microscopy was used for examining the protein translocation and results show that BDMC increased the translocation of p‐p53 and p‐H2A.X (phospho Ser140) from cytosol to nuclei in NCI‐H460 cells. In conclusion, BDMC induced DNA damage and condension and affect DNA repair proteins in NCI‐H460 cells in vitro. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1859–1868, 2016.