Ziming Li

The effect of CYP1A1 polymorphisms on the risk of lung cancer: a global meta-analysis based on 71 case–control studies

The cytochrome P450 1A1 (CYP1A1) is a phase I enzyme involved in many oxidative reactions that has attracted considerable attention as a candidate gene for lung cancer susceptibility based on its function as a key factor required for bioactivation of carcinogenic polycyclic aromatic hydrocarbons and catechol oestrogen formation. In the past decade, the relationship between CYP1A1 and lung cancer has been reported in various ethnic groups; however, these studies have yielded contradictory results. To investigate this inconsistency, we performed a meta-analysis of 71 studies involving a total of 30 368 subjects for the MspI and Ile-Val polymorphism of the CYP1A1 gene to evaluate the effect of CYP1A1 on genetic susceptibility for lung cancer. In a combined analysis, the summary per-allele odds ratios for lung cancer of the MspI and Ile-Val polymorphism were 1.19 [95% confidence interval (CI): 1.11-1.28] and 1.20 (95% CI: 1.08-1.33), respectively. Significant results were also observed using dominant or recessive genetic model. In the subgroup analysis by ethnicity, significantly increased risks were found for the MspI and Ile-Val polymorphism among East Asians in almost all genetic models. However, only marginal significant associations were detected for the MspI polymorphism among Caucasians and other population, while no significant associations were observed for the Ile-Val polymorphism in Caucasians and other population. This meta-analysis demonstrated that the MspI and Ile-Val polymorphism of CYP1A1 is a risk factor associated with increased lung cancer susceptibility, but these associations vary in different ethnic populations.

Analysis of the T Descriptors and Other Prognosis Factors in Pathologic Stage I Non-small Cell Lung Cancer in China

Background: The seventh edition of the tumor, node, metastasis Classification of Malignant Tumors is due to be published in 2009. The recommendations of International Association for the Study of Lung Cancer for changes to the T descriptors have been published. We combined this new parameter with other well-established prognostic factors and performed multivariate survival analyses to validate its value in Chinese stage I non-small cell lung cancer (NSCLC). Methods: We try to validate the new staging project in 325 patients who underwent complete surgical resection for stage I NSCLC in Single Institution of Shanghai Chest Hospital from 1998 to 2003. Variables in the analysis included age, gender, performance status, history of smoking, pathologic type, type of resection (pneumonectomy, lobectomy, and bilobectomy), tumor size (greatest dimension of tumor), T-status (T1 or T2), type of lymph node resection (systematic mediastinal lymphadenectomy or mediastinal lymph node sampling), lymphovascular vessel invasion, and adjuvant chemotherapy. Results: The 5-year overall survival (OS) of patients whose tumor measured no larger than 2 cm in largest diameter or larger than 2 cm but no larger than 3 cm were 75.49 and 74.58%, respectively. For those with tumors measured larger than 3 cm but smaller than 5 cm or larger than 5 cm but smaller than 7 cm were 60.87 and 55.63%. The 5-year OS of patients whose tumor measured larger than 7 cm was 46.15% (p = 0.025). The 5-year disease-free survival rates of patients whose tumor measured no larger than 2 cm in largest diameter or larger than 2 cm but no larger than 3 cm were 67.65 and 66.67%, respectively. For those with tumors measured larger than 3 cm but smaller than 5 cm or larger than 5 cm but smaller than 7 cm were 53.14 and 52.63%. The 5-year disease-free survival rate of patients whose tumor measured larger than 7 cm was 30.77% (p = 0.009). Multivariate analyses revealed that age, gender, type of resection (pneumonectomy, lobectomy, and bilobectomy), tumor size (greatest dimension of tumor), type of lymph node resection (systematic mediastinal lymphadenectomy or mediastinal lymph node sampling), and lymphovascular vessel invasion were significant predictive factors for OS. Conclusions: The tumor size is a significant independent prognostic factors in stage I NSCLC.

Polymorphisms of microRNA sequences or binding sites and lung cancer: a meta-analysis and systematic review.

Objective Functional single nucleotide polymorphisms (SNPs) of microRNA (miRNA) sequences or binding sites (miRNA-SNPs) are associated with lung cancer risk and survival. The objective of this study was to systematically review genetic association studies about miRNA-SNPs in lung cancer. Methods Eligible genetic association studies were retrieved from databases of PubMed, EMBASE, China National Knowledge Infrastructure and SinoMed. Two investigators selected related studies and assessed methodological quality independently. Quantitative data synthesis was conducted for common SNPs of miRNA (miRNA-196a2 rs11614913, miRNA146a rs2910164, miRNA149 rs2292832, miRNA-605 rs2043556 and miRNA499 rs3746444). GRADE profiler was used to grade the quality of evidence for each miRNA-SNP. Results 15 eligible studies and 27 miRNA-SNPs were retrieved and 10 miRNA-SNPs were reported with a significant association with susceptibility to or survival of lung cancer. Methodological quality of eligible studies was adequate with an average score of 8.5. miRNA-196a2 rs11614913 polymorphism was associated with increased lung cancer risk (homozygote comparison, OR = 1.299, 95% CI: 1.096–1.540; dominant model, OR = 1.217, 95% CI: 1.041–1.421) and decreased survival. And according to GRADE profiler, quality of evidence was moderate for MYCL1 rs3134615, while quality of the other significant associations was low. Conclusions Based on this first systematic review about miRNA-SNPs in lung cancer, quality of evidence was low for most genetic association studies. Polymorphisms of miRNA-196a2 rs11614913 and MYCL1 rs3134615 could be potential biomarkers of lung cancer.

The synergistic effect of EGFR tyrosine kinase inhibitor gefitinib in combination with aromatase inhibitor anastrozole in non-small cell lung cancer cell lines.

BACKGROUND Several studies implicated that lung cancer progression was governed by the interaction between estrogen receptor (ER) and epidermal growth factor receptor (EGFR) signaling pathways. Combined targeting of EGFR and ER may have the synergistic effect in lung cancer treatment. The aim of this study was to explore the potential utility of inhibiting these two pathways with combination of anastrozole and gefitinib in non-small cell lung cancer (NSCLC) cell lines. MATERIALS AND METHODS The expression levels of ER (ER-α and ER-β) in lung cancer cell lines (A549, H460, SPC-A-1, H1299) and normal bronchus epithelial cell BEAS-2B were detected using real-time PCR and Western blot. Immunocytochemistry was used to locate ER-α and ER-β in cell line with highest ER expression levels. The cells were treated with anastrozole or gefitinib alone or in combination. The cell proliferation inhibition was detected by the CCK8 assay, cell cycle and apoptosis effects were detected by flow cytometry; the expression levels of phosphorylated-EGFR (p-EGFR), ERK, phosphorylated-ERK (p-ERK), AKT and phosphorylated-AKT (p-AKT) were detected by Western blot. RESULTS Among these cell lines the expression levels of ER in A549 cells were highest. In A549 cell line, ER-α was mainly localized in the cytoplasm, whereas ER-β was mainly localized in the cytoplasm and to a lesser degree in the nucleus. The combination of two drugs increased the proliferation inhibition rates for 24h, 48 h, 72 h to 37.66 ± 1.02%, 63.41 ± 2.02%, 70.50 ± 0.86%, respectively, which was closely associated with elevation of the G0/G1 phase fraction (P<0.05). Apoptosis rates of A549 cells treated with anastrozole, gefitinib alone or in combination were 10.72 ± 1.12%, 17.40±1.28%, 23.02 ± 2.32%, respectively (P<0.05). The synergistic effects of the combination therapy were accompanied by reduction of p-EGFR, p-ERK and p-AKT expression compared with individual treatment. CONCLUSIONS The results of this study suggest that the combination of anastrozole and gefitinib compared with either drug alone can maximally inhibit cell proliferation, induce apoptosis, and affect downstream signaling pathways. Our study supports functional interaction between the ER and the EGFR pathways in lung cancer and provides a clinically exploitable strategy for non-small cell lung cancer patients.

Clinical analysis of postoperative venous thromboembolism risk factors in lung cancer patients

The objective of this study is to explore clinical risk factors for venous thromboembolism (VTE) in postoperative lung cancer patients in order to provide a basis for the prevention and treatment of postoperative VTE.

Effect of ubiquitin carboxy-terminal hydrolase 37 on apoptotic in A549 cells.

Proteins destined for degradation by the ubiquitin‐proteasome system are labelled with a 76‐amino acid peptide, ubiquitin, through a series of conjugation steps by the E1, E2 and E3 enzymes respectively. Ubiquitin carboxy‐terminal hydrolase 37 (UCH37) belongs to the UCH proteases family that deubiquitinates ubiquitin‐protein conjugates in the ubiquitin‐proteasome system. However, it is few reports about the relationship between UCH37 and apoptosis. In order to clarify the role of UCH37 on apoptosis, the A549 cells were chosen for this study. We transfected UCH37 siRNA and pcDNA3.1‐UCH37 plasmid into A549 cells, respectively. Using MTT assay, Western blot, Hoechst 33342 staining assay and flow cytometry, we found that silencing of UCH37 in A549 cells induced apoptosis. The ratio of Bax/Bcl‐2 was higher in silencing of UCH37 than that in control group after silencing of UCH37 in A549 cells. Meanwhile, experiments with the A549 cell line disclose that silencing of UCH37 could induce efficiently A549 cell apoptosis through activation of caspase‐9 and caspase‐3. On the other hand, over‐expression of UCH37 led to the opposite effect. Hence, UCH37 might play an important role in apoptotic through altering Bax/Bcl‐2 ratio and enzymatic activities of caspase‐9 and caspase‐3. Copyright

The polycomb group protein EZH2 inhibits lung cancer cell growth by repressing the transcription factor Nrf2

EZH2 is a key component of the polycomb PRC2 complex and functions as a histone H3 Lys27 (H3K27) trimethyltransferase. Here we show that EZH2 is down‐regulated in human non‐small cell lung cancer and low EZH2 expression predicts poor survival. Further we demonstrate that EZH2 inhibits lung cancer cell proliferation and colony formation in vitro and growth in vivo. We found that EZH2 binds to the promoter of Nrf2, where it increases H3K27me3 and represses Nrf2 expression. Finally, Nrf2 seems to be essential for the hyper proliferation of lung cancer cells in the absence of EZH2.

FBXL5-mediated degradation of single-stranded DNA-binding protein hSSB1 controls DNA damage response

Human single-strand (ss) DNA binding proteins 1 (hSSB1) has been shown to participate in DNA damage response and maintenance of genome stability by regulating the initiation of ATM-dependent signaling. ATM phosphorylates hSSB1 and prevents hSSB1 from ubiquitin-proteasome-mediated degradation. However, the E3 ligase that targets hSSB1 for destruction is still unknown. Here, we report that hSSB1 is the bona fide substrate for an Fbxl5-containing SCF (Skp1-Cul1-F box) E3 ligase. Fbxl5 interacts with and targets hSSB1 for ubiquitination and degradation, which could be prevented by ATM-mediated hSSB1 T117 phosphorylation. Furthermore, cells overexpression of Fbxl5 abrogated the cellular response to DSBs, including activation of ATM and phosphorylation of ATM targets and exhibited increased radiosensitivity, chemosensitivity and defective checkpoint activation after genotoxic stress stimuli. Moreover, the protein levels of hSSB1 and Fbxl5 showed an inverse correlation in lung cancer cells lines and clinical lung cancer samples. Therefore, Fbxl5 may negatively modulate hSSB1 to regulate DNA damage response, implicating Fbxl5 as a novel, promising therapeutic target for lung cancers.

Regulation of SIRT2 levels for human non-small cell lung cancer therapy

Seven Sirtuin family members (SIRT1-7), comprising a family of NAD+-dependent protein deacetylases and ADP-ribosyltransferases, are key proteins that regulate multiple physiological processes. SIRT2 was recently reported to play an important role in carcinogenesis. However, its role in non-small cell lung cancer (NSCLC) has not yet been investigated. In this study, we analyzed the expression pattern of SIRT2 in NSCLC tissues from clinical patients and in cell lines, and found that SIRT2 was significantly down-regulated at both the mRNA and protein levels in tumor than non-tumor tissues or cells, which were corroborated by the NSCLC tissue microarray results. Overexpression of SIRT2 in A549 and H1299 cells caused cell proliferation inhibition, cell apoptosis induction and cell cycle arrest. Further analysis showed that SIRT2 overexpression increased the ROS (reactive oxygen species) production and p27 levels. Moreover, up-regulation of SIRT2 in NSCLC cells increased the sensitivity to Cisplatin treatment. Taken together, our results implied that down-regulation of SIRT2 was associated with NSCLC, and regulation of SIRT2 might be an important target for NSCLC therapy.

FGFR1 promotes the stem cell-like phenotype of FGFR1-amplified non-small cell lung cancer cells through the Hedgehog pathway

Cancer stem cell-like phenotype is critical for tumor formation and treatment resistance. FGFR1 is found to be amplified in non-small cell lung cancer, particularly in the lung squamous cell cancer (LSCC). Whether FGFR1 contributes to the maintenance of stem cell-like phenotype of FGFR1-amplified lung cancer cells remains elusive. In this study, treatment with FGFR1 inhibitor AZD4547 suppressed the growth of tumor spheres and reduced ALDH positive proportion in FGFR1-amplified lung cancer cells in vitro, as well as inhibited the growth of oncospheres and parental cells in xenograft models. Knockdown of FGFR1 recaptured the similar effect as AZD4547 in vitro. Furthermore, activation of FGFR1 and subsequently its downstream ERK signaling enhanced the expression and transcriptional activity of GLI2, which could be blocked by FGFR1 inhibitor/silencing or ERK inhibitor. Knockdown of GLI2 directly inhibited the stem-like phenotype of FGFR1-amilified cells, whereas overexpression of GLI2 sufficiently rescued the phenotype caused by FGFR1 knockdown. Notably we also identified a correlation between FGFR1 and GLI2 expressions from clinical data, as well as an inverse relationship with progression free survival (PFS). Together our study suggests that the FGFR1/GLI2 axis promotes the lung cancer stem cell-like phenotype. These results support a rational strategy of combination of FGFR1 and GLI inhibitors for treatment of FGFR1-amplified lung cancers, especially LSCC.