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Background. Recent studies suggest that long-term exposure of the carcinogen 4-methylnitrosamino-1--3-pyridyl-1-butanone (NNK) found in tobacco smoke is involved in the progression of head and neck squamous cell carcinoma (HNSCC). The underlying nicotine-mediated mechanism remains unclear. Methods. An analysis of SCC-25 and Fadu cells with or without NNK exposure focusing on the evaluation of migration and invasion abilities, the expression of epithelial--mesenchymal transition, drug-resistance-related genes, properties of cancer stem cells (CSCs), and anti-apoptosis was performed. Results. Long-term NNK exposure enhances migration and invasion with morphological alterations in a dose-dependently manner. Furthermore, NNK exposure also upregulates Snail, promotes sphere-forming ability, Background. Recent studies suggest that long-term exposure of the carcinogen 4-methylnitrosamino-1-3-pyridyl-1-butanone (NNK) found in tobacco smoke is involved in the progression of head and neck squamous cell carcinoma (HNSCC). The underlying nicotine-mediated mechanism remains unclear. Methods. An analysis of SCC-25 and Fadu cells with or without NNK exposure focusing on the evaluation of migration and invasion abilities, the expression of epithelial--mesenchymal transition, drug-resistance-related genes, properties of cancer stem cells (CSCs), and anti-apoptosis was performed. Results. Long-term NNK exposure enhances migration and invasion with morphological alterations in a dose-dependently manner. Furthermore, NNK exposure also upregulates Snail, promotes sphere-forming ability, and overexpresses aldehyde dehydrogenase 1 (ALDH1), Nanog, OCT4, ABCG2, and MDR1. Conclusion. The current study confirmed that long-term NNK exposure plays a role in HNSCC by increasing anti-apoptosis and therapeutic resistance via the Snail-RKIP signaling pathway. Our data also suggest that a7 nicotinic acetylcholine receptor (α7-nAChR) inhibition or targeting Snail may provide a feasible rationale for preventing the progression of HNSCC. [ABSTRACT FROM AUTHOR]

Background: Metastasis occurs in a series of discrete steps involving invasion, angiogenesis, lymphovascular space permeation, and establishment of secondary tumors. Malignant pleural effusion (MPE), a type of tumor metastasis, is usually a poor prognostic sign for patients with pulmonary adenocarcinoma, although its underlying mechanism has received less attention than other types of metastases have. The objective of the current study was to confirm whether cancer stem cells (CSCs) in MPE contribute to the “metastatic cascade” through the epithelial – mesenchymal transition (EMT), anoikis, and adaptation in the microenvironment. Methods: Pulmonary tissue and corresponding cell blocks of MPE samples from 20 patients with primary adenocarcinoma were analyzed by immunohistochemical staining with CSC-representative markers (CD133, Nanog, and OCT-4) and EMT-associated markers (E-cadherin and vimentin). Correlations between these variables and clinico-pathological parameters were analyzed. Primary cultures from eight cases of MPE were investigated to characterize the CSC properties, including marker expression, sphere formation, and differentiation. Results: Expressions of CSC-representative markers for 20 cases of MPE cell blocks were quite diverse and variable ranging from 15% to 90%. Stronger expression of CSC-representative markers and alteration of EMT-associated markers were found at the invasive fronts and in MPEs compared with the expression in primary pulmonary tumor tissues. The expression of OCT-4 in MPEs significantly related to distant metastasis and stage, as well as inversely correlated with patient survival. Primary cultures confirmed the CSC properties in MPE. Five of eight cases of MPE yielded adequate cell clusters, which also showed variable expressions of CSC markers in addition to sphere formation and the ability for differentiation and metastasis. Conclusion: This pilot study offers a better understanding of the metastatic cascade. Establishing a model of MPE will provide further insight into the role of CSCs in metastasis and may explain the high therapeutic failure rates for patients with MPE. [ABSTRACT FROM AUTHOR]

Abstract: Background: Despite increased experience in therapy, the overall outcome of oral squamous cell carcinoma (OSCC) has not improved because of the relative resistance to chemotherapeutic drugs in addition to local invasion and frequent regional lymph node metastases. Quercetin (Qu) is a principal flavonoid compound and an excellent free-radical-scavenging antioxidant that promotes apoptosis. Limited reports regarding the molecular or cellular role of Qu in anticancer properties on OSCC have been presented. This study was conducted to clarify the efficacy of Qu on OSCC in vitro and further to evaluate the possible mechanism(s). Methods: Cultured OSCC cells (SCC-25) and human gingival fibroblasts (HGFs) were treated with different concentrations of Qu. Cell viability and cell colony-forming potential were detected with the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) and colony growth assays. Cell-cycle analysis and apoptosis were measured by flow cytometry. Cell migration and invasion were tested using the micropore chamber assay. Results: Cell viability and colony-forming potential were decreased in a dose-dependent manner following Qu treatment. Qu also dose-dependently inhibited the proliferation of SCC-25 cells via both G1 phase cell cycle arrest and mitochondria-mediated apoptosis. In addition, Qu also decreased the abilities of migration and invasion of SCC-25 cells in a dose-dependent manner. Conclusion: Qu effectively inhibits cell growth and invasion/migration of SCC-25 cells in vitro. The cellular and molecular mechanisms are via cell cycle arrest accompanied by mitochondria-mediated apoptosis. Our findings suggest that Qu may have potential as a new chemopreventive agent or serve as a therapeutic adjuvant for OSCC. [Copyright &y& Elsevier]

Although many studies have shown the association between smoking and the increased incidence and adverse prognosis of head and neck squamous cell carcinoma (HNSCC), the mechanisms and pharmaceutical targets involved remain unclear. Here, we integrated gene expression signatures, genetic alterations, and survival analyses to identify prognostic indicators and therapeutic targets for smoking HNSCC patients, and we discovered that the FDA-approved drug varenicline inhibits the target for cancer cell migration/invasion. We first identified 18 smoking-related and prognostic genes for HNSCC by using RNA-Seq and clinical follow-up data. One of these genes, CHRNB4 (neuronal acetylcholine receptor subunit beta-4), increased the risk of death by approximately threefold in CHRNB4-high expression smokers compared to CHRNB4-low expression smokers (log rank, p = 0.00042; hazard ratio, 2.82; 95% CI, 1.55–5.14), former smokers, and non-smokers. Furthermore, we examined the functional enrichment of co-regulated genes of CHRNB4 and its 246 frequently occurring copy number alterations (CNAs). We found that these genes were involved in promoting angiogenesis, resisting cell death, and sustaining proliferation, and contributed to much worse outcomes for CHRNB4-high patients. Finally, we performed CHRNB4 gene editing and drug inhibition assays, and the results validate these observations. In summary, our study suggests that CHRNB4 is a prognostic indicator for smoking HNSCC patients and provides a potential new therapeutic drug to prevent recurrence or distant metastasis. [ABSTRACT FROM AUTHOR]