Zhengtang Chen

Increased IL-17-producing cells correlate with poor survival and lymphangiogenesis in NSCLC patients

The presence of IL-17-positive cells is observed in a variety of inflammatory associated cancers and IL-17 has been found to be involved in angiogenesis. The aim of this study is to determine the prognostic significance of IL-17 in NSCLC patients and to examine the correlation between IL-17 expression and lymphatic vessel density in NSCLC tissues. The expression of IL-17 was measured by immunohistochemistry in 52 paraffin-embedded tissues with non-small cell lung cancer. The chi(2) test was used to analyze the correlation between IL-17 expression and clinical parameters and lymphatic vessel density (LVD). The Kaplan-Meier method, univariate and multivariate regression analysis was used to analyze the correlation between IL-17 expression and overall survival and disease-free survival. High expression of IL-17 was observed in 25 of 52 lung cancer patients and was associated with smoking status, TNM stage, LVD, overall survival and disease-free survival. Univariate and multivariate analysis showed that IL-17 was an independent prognostic factor for overall survival and disease-free survival. Our results indicate that IL-17 may play a role in the metastasis of lung cancer by promoting lymphangiogenesis. IL-17 expression is an independent prognostic factor in both overall and disease-free survival in NSCLC.

Autocrine CCL5 signaling promotes invasion and migration of CD133+ ovarian cancer stem-like cells via NF-κB-mediated MMP-9 upregulation.

The concept of cancer stem cells (CSCs) proposes that solely CSCs are capable of generating tumor metastases. However, how CSCs maintain their invasion and migration abilities, the most important properties of metastatic cells, still remains elusive. Here we used CD133 to mark a specific population from human ovarian cancer cell line and ovarian cancer tissue and determined its hyperactivity in migration and invasion. Therefore, we labeled this population as cancer stem‐like cells (CSLCs). In comparison to CD133− non‐CSLCs, chemokine CCL5 and its receptors, CCR1, CCR3, and CCR5, were consistently upregulated in CSLCs, and most importantly, blocking of CCL5, CCR1, or CCR3 effectively inhibits the invasive capacity of CSLCs. Mechanistically, we identified that this enhanced invasiveness is mediated through nuclear factor κB (NF‐κB) activation and the consequently elevated MMP9 secretion. Our results suggested that the autocrine activation of CCR1 and CCR3 by CCL5 represents one of major mechanisms underlying the metastatic property of ovarian CSLCs. STEM CELLS2012;30:2309–2319

Short interfering RNA directed against TWIST, a novel zinc finger transcription factor, increases A549 cell sensitivity to cisplatin via MAPK/mitochondrial pathway

Previous reports have implicated epithelial-mesenchymal transition (EMT) as a major cause of cancer. TWIST, a novel zinc finger transcription factor, was suggested to be an important inducer of EMT and therefore be involved in different phases of tumorigenicity. However, whether TWIST suppression could increase chemosensitivity of cancer cells to chemotherapeutic agent remains unclear. In the present study, we utilized RNA interference to knockdown TWIST expression in A549 cells and further assessed the cell viability and apoptosis as well as possible MAPKs and mitochondrial pathways. The data showed that TWIST depletion significantly sensitized A549 cells to cisplatin by inducing activation of JNK/mitochondrial pathway but not ERK and p-38 pathways, suggesting critical roles of TWIST in A549 cell chemoresistance to cisplatin and raising the possibility of TWIST depletion as a promising approach to lung cancer therapy.

Knockdown of Snail, a novel zinc finger transcription factor, via RNA interference increases A549 cell sensitivity to cisplatin via JNK/mitochondrial pathway

Previous reports have implicated epithelial-mesenchymal transition (EMT) as a major cause of cancer. Snail, a novel zinc finger transcription factor, was suggested to be an important inducer of EMT and therefore be involved in different phases of tumorigenicity. However, whether Snail could increase chemoresistance of cancer cells to chemotherapeutic agent remains unclear. To evaluate the roles and possible mechanisms of Snail in chemoresistance of lung cancer cells to cisplatin, we utilized RNA interference to knockdown Snail expression in A549 cells and further assessed the cell viability and apoptosis as well as possible signaling transduction pathways. The data showed that Snail depletion sensitized A549 cells to cisplatin possibly by inducing activation of JNK/mitochondrial pathway, suggesting critical roles of Snail in A549 cell chemoresistance to cisplatin and raising the possibility of Snail depletion as a promising approach to lung cancer therapy.

MicroRNA expression profile of bronchioalveolar stem cells from mouse lung.

Increasing evidence has suggested that bronchioalveolar stem cell (BASC) is the progenitor cells of lung cancer stem cells. However, the mechanisms by which self-renewal of BSACs is controlled and how BASCs turn into cancer stem cells still remains to be unknown. In the present study, we successfully isolated bronchioalveolar stem cells (BASCs) from mouse lung using FACS. These BASCs were characterized by clonal growth, self-renewal and high capacity for differentiation, suggesting that these BASCs are indeed stem cells. We investigated the microRNA (miRNA) expression profile of these BASCs using miRNA array and quantitative RT-PCR. We discovered that BASCs possessed a unique miRNA profile, with altered expression of several microRNAs, such as miR-142-3p, miR-451, miR-106a, miR-142-5p, miR-15b, miR-20a, miR-106b, miR-25, miR-486, in BASCs compared to control cells. Our results suggest that microRNAs might play important roles in maintaining the self-renewal capacity of BASCs, and suggest the intriguing possibility that aberrant expression of microRNAs could involved in turning BASCs into lung cancer stem cells.

CYP1A1 and GSTM1 polymorphisms and oral cancer risk: association studies via evidence-based meta-analyses.

Previous studies have implicated CYP1A1 and GSTM1 polymorphisms as risk factors for various cancers. A number of studies have been devoted to the association of CYP1A1 or GSTM1 polymorphism with susceptibility to oral carcinoma and have yielded conflicting results. The aim of the present study was to assess the possible associations of oral cancer risk with CYP1A1 genetic variation and GSTM1 null genotype respectively via systematic meta-analyses. The data suggest that variant genotypes of CYP1A1 might not be risk factors for oral cancer, whereas GSTM1 null genotype significantly increases susceptibility to oral cancer in Asians but not Caucasians.

Association Studies of CYP1A1 and GSTM1 Polymorphisms with Esophageal Cancer Risk: Evidence-based Meta-analyses

BACKGROUND AND AIMS Previous studies have implicated cytochrome P450 1A1 (CYP1A1) and glutathione S-transferase M1 (GSTM1) polymorphisms as risk factors for various cancers. A number of studies have been devoted to the association of CYP1A1 or GSTM1 polymorphism with susceptibility to esophageal carcinoma and have yielded conflicting results. We undertook this study to assess possible associations of esophageal cancer risk with CYP1A1 genetic variation and GSTM1 null genotype, respectively. METHODS We conducted a search in MEDLINE, EMBASE and Chinese National Knowledge Infrastructure (CNKI) without a language limitation, covering all papers published until May 2008. The associated literature was acquired through deliberate searching and selected based on the established inclusion criteria for publications. RESULTS Ultimately, 26 studies met the included criteria and thus were selected. Relevant data were extracted and further analyzed using systematic meta-analyses. Results showed that the overall OR for CYP1A1 Msp1 polymorphism was 1.24 (95% CI = 0.84-1.83). Restricting analyses to ethnic groups and histological groups, data failed to show a correlation between CYP1A1 Msp1 polymorphism and esophageal cancer risk. Overall OR for CYP1A1 exon7 polymorphism was 1.37 (95% CI = 1.06-1.77), and subgroup analyses showed that CYP1A1 exon7 polymorphism increases esophageal cancer risk in Asians but not in Caucasians. As for GSTM1 deficiency, the overall OR was 1.20 (95% CI = 0.96-1.49), and further subgroup analyses failed to show a marked association of GSTM1 deletion with esophageal cancer. CONCLUSIONS Results of the present study suggest that CYP1A1 exon7 polymorphisms may be a risk factor for esophageal cancer in Asians but not in Caucasians, whereas neither CYP1A1 Msp1 nor GSTM1 polymorphism was associated with increased susceptibility to esophageal cancer.

The effects of artesunate on the expression of EGFR and ABCG2 in A549 human lung cancer cells and a xenograft model.

Non-small cell lung cancer (NSCLC) is the leading cause of cancer death worldwide. Clinical and laboratory studies have suggested that multi-targeting approaches against neoplastic cells could help to increase patient survival and might reduce the emergence of cells that are resistant to single-target inhibitors. Artesunate (ART) is one of the most potent and rapidly acting antimalarial agents known, and it also exerts a profound cytotoxic activity toward cancer cells and reverses multi-drug resistance. In the present study, we found that artesunate inhibited NSCLC A549 cell growth and proliferation, induced apoptosis and suppressed tumor growth in a dose-dependent manner in A549 cells and a mouse xenograft model. Furthermore, artesunate down-regulated the expression of epidermal growth factor receptor (EGFR), Akt and ATP-binding cassette subfamily G member 2 (ABCG2) at the mRNA and protein levels in vitro and in vivo. In conclusion, artesunate is an effective anti-cancer drug that may enhance the effectiveness of other anticancer drugs and may reverse multi-drug resistance by suppressing the transcription of ABCG2, which inhibits drug efflux.

The Expression of RNA-Binding Protein HuR in Non-Small Cell Lung Cancer Correlates with Vascular Endothelial Growth Factor-C Expression and Lymph Node Metastasis

The expression levels of the RNA-binding protein Hu antigen (HuR) and vascular endothelial growth factor-C (VEGF-C) were examined immunohistochemically in 81 non-small cell lung cancers (NSCLC) and 15 benign human lung tissues. HuR showed a nuclear overexpression in 82.7% (67/81) of NSCLC specimens. Cytoplasmic immunoreactivity for HuR was observed in 45.7% (37/81) of NSCLC, while only nuclear expression of HuR was observed in 13.3% (2/15) of benign lung tissues. The expression of VEGF-C was present in a subgroup of 70.4% (57/81) of tumor cases. In the human NSCLC samples, cytoplasmic but not nuclear HuR expression was significantly associated with increased levels of VEGF-C and with clinicopathological variables, including high tumor grade, poor differentiation and lymph node metastasis. In vitro, HuR showed a predominantly nuclear staining in Lewis lung cancer cells, as seen by confocal microscopy. When lung cancer cells were treated with siRNA targeted against HuR, expression levels of the HuR and VEGF-C proteins were significantly reduced, as seen by Western blotting. Our findings indicate that there is a dysregulation of the cellular distribution of the mRNA stability factor HuR in a subset of NSCLC. Examination of cytoplasmic HuR in NSCLC tissues will allow for valuable prognostic diagnosis of lymph node metastasis, as HuR might be an important mediator regulating the expression of VEGF-C.

miR‑223 functions as a potent tumor suppressor of the Lewis lung carcinoma cell line by targeting insulin‑like growth factor‑1 receptor and cyclin-dependent kinase 2

microRNAs (miRNAs) have been hypothesized to function as oncogenes or tumor suppressors by targeting specific cancer-related genes. Previous studies have reported that miR-223 may serve as a tumor suppressor in a number of cancer types, however, knowledge of its targets in non-small cell lung cancer (NSCLC) remains limited. In the current study, miR-223 was found to inhibit cell proliferation in vitro by CCK-8 assay, growth curves and an anchorage-independent growth assay in a Lewis lung carcinoma (LLC) cell line. miR-223 transfection in the LLC cells was observed to significantly inhibit migration and invasion, induce G2/M arrest and decrease the expression levels of Sca-1, a marker of murine stem cells. In addition, miR-223 transfection markedly suppressed AKT and ERK signaling, as well as insulin-like growth factor-1 receptor (IGF-1R)-mediated downstream signaling, pathways that are crucial for cell proliferation and invasion in NSCLC cells. Analyses in C57BL/6 mice demonstrated that miR-223 suppresses tumorigenicity in vivo. Using a luciferase activity assay and western blot analysis, IGF-1R and cyclin-dependent kinase 2 (CDK2) were identified as direct targets of miR-223. In the present study, novel cancer-related targets of miR-223 were identified and verified in a LLC cell line, indicating that miR-223 functions as a tumor suppressor, which may fine-tune the activity of the IGF-1R pathway in lung cancer. Therefore, increasing miR-223 expression may provide a novel approach for the treatment of NSCLC.