[Show abstract][Hide abstract] ABSTRACT: Epidermal growth factor receptor (EGFR) activating mutations are a predictor of tyrosine kinase inhibitor effectiveness in the treatment of non-small-cell lung cancer (NSCLC). The objective of this study is to build a model for predicting the EGFR mutation status of brain metastasis in patients with NSCLC.Observation and model set-up.This study was conducted between January 2003 and December 2011 in 6 medical centers in Southwest China.The study included 31 NSCLC patients with brain metastases.Eligibility requirements were histological proof of NSCLC, as well as sufficient quantity of paraffin-embedded lung and brain metastases specimens for EGFR mutation detection. The linear discriminant analysis (LDA) method was used for analyzing the dimensional reduction of clinical features, and a support vector machine (SVM) algorithm was employed to generate an EGFR mutation model for NSCLC brain metastases. Training-testing-validation (3 : 1 : 1) processes were applied to find the best fit in 12 patients (validation test set) with NSCLC and brain metastases treated with a tyrosine kinase inhibitor and whole-brain radiotherapy.
EGFR mutation analysis in patients with NSCLC and brain metastases and the development of a LDA-SVM-based EGFR mutation model for NSCLC brain metastases patients.EGFR mutation discordance between the primary lung tumor and brain metastases was found in 5 patients. Using LDA, 13 clinical features were transformed into 9 characteristics, and 3 were selected as primary vectors. The EGFR mutation model constructed with SVM algorithms had an accuracy, sensitivity, and specificity for determining the mutation status of brain metastases of 0.879, 0.886, and 0.875, respectively. Furthermore, the replicability of our model was confirmed by testing 100 random combinations of input values.The LDA-SVM-based model developed in this study could predict the EGFR status of brain metastases in this small cohort of patients with NSCLC. Further studies with larger cohorts should be carried out to validate our findings in the clinical setting.
Medicine 02/2015; 94(5):e375. DOI:10.1097/MD.0000000000000375 · 5.72 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: APE1 is a multifunctional protein that has recently been implicated in protecting cells from oxidative stress. In current study, we confirmed that APE1's effect on cellular antioxidant capacity is related to its redox activity through the use of an APE1 functional mutant, and we investigated the mechanism through which this multifunctional protein affects the function of the transcription factor Nrf-2 in regulating oxidative stress-induced genes. Using a pair of mutants for both the redox activity and acetylation-regulated activity of APE1, in vitro assays showed that the redox activity of APE1 is crucial for its nuclear association with Nrf-2 and subsequent activation of Nrf-2′s transcription of several downstream genes during oxidative challenge. Important oxidative stress genes are to be affected by APE1 redox activity, including Hmox1, Gstm1, and Txnrd1. In addition, utilizing human non-small cell lung cancer sample tissue as well as a nude mouse xenograft model, we determined that APE1 expression levels are inversely correlated to oxidative stress in vivo. These findings implicated that interference with these crucial functions of APE1 shows promise in preventing resistance to certain radiotherapies and indicated that further research is necessary to understand APE1′s complex roles in regulating both the basal redox status and oxidative stress state of the cellular environment.
Free Radical Biology and Medicine 10/2014; 78. DOI:10.1016/j.freeradbiomed.2014.10.007 · 5.74 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The aim of the study was to investigate the role of genistein in alleviating radiation-induced pneumonitis (RIP) through down-regulating levels of the inflammatory cytokines by inhibiting the expression of apurinic/apyrimidinic endonuclease 1/redox factor-1 (Ape1/Ref-1). Fifty female C57BL/6J mice (8 weeks old) were randomly divided into a control group, a pure irradiation (IR) group and a genistein + IR group. At the four time points after IR, hematoxylin, and Masson's trichrome stainings were used to examine the pathological changes and collagen fiber deposition. Flow cytometry was used to detect reactive oxygen system (ROS) changes, EMSA was used to estimate the nuclear factor kappa B (NF-κB) transcriptional activities and an ELISA assay was used to measure the levels of TGF-β1, IL-1β, TNF-α, and IL-6 in the serum and bronchoalveolar lavage fluid (BALF) 2 weeks after IR. The pathological detection results showed acute inflammatory/fibrinoid exudation of the thoracic tissue after IR, which was significantly alleviated with genistein. The IR-induced an APE1 protein expression increase and NF-κB was effectively suppressed by genistein (P < 0.05). The induction of the inflammatory cytokines TGF-β1, IL-1β, TNF-α, and IL-6 by IR were in turn inhibited in the serum and BALF of the genistein-pretreated mice (P < 0.05). In addition, the ROS production was significantly boosted in the A549 cells after IR, which could be down-regulated by the pretreatment of genistein. The results demonstrate that genistein alleviates RIP by attenuating the inflammatory response in the initiation of RIP. A possible target of genistein is the Ape1/ref-1, which regulates key inflammatory cytokines by activating the NF-κB.
[Show abstract][Hide abstract] ABSTRACT: Vitamin D plays a central role in cellular proliferation, apoptosis induction, and tumor growth suppression. The vitamin D receptor (VDR) is a crucial mediator for the cellular effects of vitamin D. A series of epidemiological studies have examined the association between the VDR FokI polymorphism and breast cancer risk, but the findings remain inconclusive. Fifteen eligible case-control studies involving 15,681 cancer cases and 20,632 control subjects were identified through searching PubMed, Embase, and Web of Science. Odds ratios (ORs) and 95 % confidence intervals (CIs) were used to assess the association. Heterogeneity across studies was examined with the chi-square-based Q test and the I (2) index. Begg's and Egger's test were also performed to determine publication bias. All statistical data were analyzed by STATA software. The combined estimates did not show significant risks correlated with the FokI polymorphism. However, we found an increased risk in the subgroup analysis by source of control (OR = 1.11, 95 % CI = 1.01-1.22; heterogeneity test: P = 0.116, I (2) = 0.0 % for ff vs FF; OR = 1.10, 95 % CI = 1.01-1.21; heterogeneity test: P = 0.832, I (2) = 0.0 % for ff vs Ff + FF). This meta-analysis suggests that the presence of FokI polymorphism may contribute to the risk of breast cancer in Caucasians.
[Show abstract][Hide abstract] ABSTRACT: The effects of all-trans retinoic acid (ATRA) on cancer are complex. ATRA has anti-cancer effects as it promotes cancer cell differentiation. However, ATRA also up-regulates expression of vascular endothelial growth factor (VEGF) in cancer cells, which leads to angiogenesis and can, thus, facilitate cancer growth. Genistein, a crucial non-nutrient component in soybean, exhibits anti-cancer effects by inhibiting protein tyrosine kinase that is involved in up-regulation of VEGF. We hypothesized that genistein, applied simultaneously with ATRA, would counter its undesired angiogenic effects and, thus, enhance the anti-cancer effects of ATRA. The purpose of this study was to document potential synergistic effects of genistein and ATRA in A549 lung adenocarcinoma cells. We further explored the role of genistein on countering the ATRA-induced VEGF expression. We demonstrate that genistein enhances the ATRA-induced growth inhibition of A549 cells by promoting apoptosis. Further, the combined use of ATRA and genistein leads to cancer cell arrest in G0/G1 and G2/M cell cycle phases. Finally, expression of VEGF (both mRNA and protein) was diminished in A549 cells exposed to both ATRA and genistein. In conclusion, our results demonstrate that genistein effectively enhances anti-cancer effects of ATRA, particularly, by countering the ATRA-induced up-regulation of VEGF. Our study provides an experimental basis for combined use of ATRA and genistein in the treatment of lung cancer.
[Show abstract][Hide abstract] ABSTRACT: Non-metastatic protein-23 homolog-1 (Nm23-H1) is a multifunctional protein with DNase and histidine protein kinase activities. Human apurinic endonuclease-1 (APE1) is the AP endonuclease DNA base excision repair (BER) enzyme involved in several important cellular functions. Since the relationship between Nm23-H1 and APE1 proteins is unclear, we evaluated their interaction at different time points after irradiating human lung cancer A549 cells with X-rays. We found that Nm23-H1 and APE1 overexpression was induced by irradiation in a dose- and time-dependent manner. Subcellular distribution pattern of both proteins was reversed after irradiation. After irradiation, APE1 that initially showed nuclear localization was gradually increased in the cytoplasm, whereas Nm23-H1 that mainly showed cytoplasmic localization was gradually increased in the nuclei of A549 cells. Nm23-H1 and APE1 interaction was demonstrated by His-pull-down and co-immunoprecipitation assays. The presence of Nm23-H1/APE1 complex in X-ray-irradiated A549 cells was also detected by DNA affinity precipitation analysis of a DNA fragment containing an AP site. Although the AP endonuclease activity of Nm23-H1 was too weak to be detected, the AP endonuclease activity of APE1 was increased with the enhanced Nm23-H1 expression. In conclusion, our data point to a mechanism by which Nm23-H1 protects cells against oxidative stress through the engagement of DNA BER enzyme APE1.
[Show abstract][Hide abstract] ABSTRACT: To study the chemosensitivity of lung adenocarcinoma cell line A549 cells to liposome-encapsulated paclitaxel after treatment by nm23-H1-small interference RNA (nm23-H1-siRNA) in vitro.
The A549 cells were divided into two groups: non-transfected group and nm23-H1-siRNA-transfected group. Western blot analysis was used to detect the expression of nm23-H1. MTT and flow cytometry were used to determine the cell mortality rate, apoptosis rate and cell cycle after liposome-encapsulated paclitaxel treatment in both groups.
The expression of nm23-H1 in A549 cells was significantly decreased after transfection with nm23-H1-siRNA. After treatment for 48 hours with liposome-encapsulated paclitaxel, the cell mortality rate was increased with the increasing concentration of liposome-encapsulated paclitaxel in both groups, but increased higher in the nm23-H1-siRNA-transfected group. When the concentration of liposome-encapsulated paclitaxel was above 5 µg/ml, the cell mortality rate was significantly higher than that in the non-transfected group (P < 0.05). The proportion of apoptotic cells also increased in the nm23-H1-siRNA-transfected group, compared with that of the non-transfected group (t = 3.812, P < 0.05), while the proportion of cells at S and G(2)/M phase decreased after transfection with nm23-H1-siRNA (S phase:t = 8.356, P < 0.05; G(2)/M phase:t = 7.256, P < 0.05).
Nm23-H1 is related with the chemoresistance to liposome-encapsulated paclitaxel in lung adenocarcinoma cell line A549 cells. Inhibition of the expression of nm23-H1 by nm23-H1-siRNA can improve the in vitro chemosensitivity of A549 cells to liposome-encapsulated paclitaxel.
Zhonghua zhong liu za zhi [Chinese journal of oncology] 06/2011; 33(6):405-9. DOI:10.3760/cma.j.issn.0253-3766.2011.06.002
[Show abstract][Hide abstract] ABSTRACT: Reactive oxygen species (ROS) and numerous carcinogens may cause DNA damage including oxidative base lesions that contribute to the risk of lung cancer. The base excision repair (BER) pathway could effectively remove oxidative lesions in which 8-oxoguanine glycosylase-1 (OGG1), x-ray repair cross-complementing 1 (XRCC1), and apurinic/apyimidinic endonuclease 1 (APE1) play key roles. The aim of this study was to analyze the polymorphisms of DNA BER genes (OOG1, XRCC1 and APE1) and explore their associations, and the combined effects of these variants, with risk of lung cancer.
In a hospital-based, case-control study of 455 lung cancer cases and 443 cancer-free hospital controls, the SNPs of OGG1 (Ser326Cys), XRCC1 (Arg399Gln), APE1 (Asp148Glu and -141T/G) were genotyped and analyzed for their correlation with the risk of lung cancer in multivariate logistic regression models.
Individuals homozygous for the variants APE1 -141GG showed a protective effect for lung cancer overall (OR=0.62; 95% CI: 0.42-0.91; p=0.02) and for lung adenocarcinoma (OR=0.65; 95% CI, 0.44-0.96; p=0.03). When analyzing the combined effects of variant alleles, 84 patients and controls were identified who were homozygous for two or three of the potential protective alleles (i.e., OGG1 326Cys, XRCC1 399Gln and APE1 -141G). ORs were significantly reduced when all patients were analyzed (OR=0.62; 95% CI: 0.38-0.99; p=0.05).
The combined effects of polymorphisms within BER genes may contribute to the tumorigenesis of lung cancer.
Archives of medical research 04/2011; 42(3):226-34. DOI:10.1016/j.arcmed.2011.04.005 · 2.65 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The aim of the study was to obtain stable radioresistant sub-lines from the human cervical cancer cell line HeLa by prolonged exposure to 252Cf neutron and X-rays. Radioresistance mechanisms were investigated in the resulting cells using microarray analysis of DNA damage repair genes.
HeLa cells were treated with fractionated 252Cf neutron and X-rays, with a cumulative dose of 75 Gy each, over 8 months, yielding the sub-lines HeLaNR and HeLaXR. Radioresistant characteristics were detected by clone formation assay, ultrastructural observations, cell doubling time, cell cycle distribution, and apoptosis assay. Gene expression patterns of the radioresistant sub-lines were studied through microarray analysis and verified by Western blotting and real-time PCR.
The radioresistant sub-lines HeLaNR and HeLaXR were more radioresisitant to 252Cf neutron and X-rays than parental HeLa cells by detecting their radioresistant characteristics, respectively. Compared to HeLa cells, the expression of 24 genes was significantly altered by at least 2-fold in HeLaNR cells. Of these, 19 genes were up-regulated and 5 down-regulated. In HeLaXR cells, 41 genes were significantly altered by at least 2-fold; 38 genes were up-regulated and 3 down-regulated.
Chronic exposure of cells to ionizing radiation induces adaptive responses that enhance tolerance of ionizing radiation and allow investigations of cellular radioresistance mechanisms. The insights gained into the molecular mechanisms activated by these "radioresistance" genes will lead to new therapeutic targets for cervical cancer.
BMC Cancer 02/2010; 10(1):71. DOI:10.1186/1471-2407-10-71 · 3.36 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Apurinic/apyrimidinic endonuclease (APE1), a bifunctional AP endonuclease/redox factor, is important in DNA repair and redox signaling, may be associated with chemoresistance. In this study, we first investigated APE1 expression and its correlation with cisplatin resistance and prognosis in non-small cell lung cancer (NSCLC) patients. Then, we investigated the effect of chimeric adenoviral vector Ad5/F35 carrying human APE1 siRNA (Ad5/F35-APE1 siRNA) on the sensitivity of cisplatin in A549 human lung adenocarcinoma cells.
Tumor specimens from 103 patients with operable NSCLC were obtained from 1999 to 2001. Among these patients, 72 patients have been treated with at least three cycles of cisplatin-based chemotherapy. APE1 protein expression was examined by immunohistochemistry and Western blot on the tumor samples and a cultured A549 cell line, respectively. Cell survival and apoptosis were determined by MTT and TUNEL, respectively.
83.3% (20/24) cisplatin-resistant tumors showed high APE1 expression levels, while 8.3% (4/48) cisplatin-sensitive tumors showed high APE1 expression levels (p<0.01). Univariate analysis indicated that overall survival and disease-free survival were significantly better in NSCLC patients with low vs those with high APE1 expression levels (p<0.01). Treatment with cisplatin resulted in a dose-dependent increase in APE1 protein expression in A549 cells, and Ad5/F35-APE1 siRNA effectively inhibited APE1 expression. Ad5/F35-APE1 siRNA significantly enhanced sensitivity of A549 cells to cisplatin, associated with increased cell apoptosis.
Our results indicate that APE1 is a new promising target for the combination of cisplatin-based chemotherapy in NCSLC patients.