Repetitive Nicotine Exposure Leads to a More Malignant and Metastasis-Prone Phenotype of SCLC: A Molecular Insight into the Importance of Quitting Smoking during Treatment

Rare thoracic cancers: a comprehensive overview of diagnosis and management of small cell lung cancer, malignant pleural mesothelioma and thymic epithelial tumours

Despite the progress in outcomes seen with immunotherapy in various malignancies, including nonsmall cell lung cancer, the benefits are less in small cell lung cancer, malignant pleural mesothelioma and thymic epithelial tumours. New effective treatment options are needed, guided via more in-depth insights into the pathophysiology of these rare malignancies. This review comprehensively presents an overview of the clinical presentation, diagnostic tools, staging systems, pathophysiology and treatment options for these rare thoracic cancers. In addition, opportunities for further improvement of therapies are discussed.

CCL19 associates with lymph node metastasis and inferior prognosis in patients with small cell lung cancer

OBJECTIVE

Small cell lung cancer (SCLC) is a systemic disease and most patients have metastases at diagnosis. Better understanding of the underlying mechanisms of SCLC metastasis may provide potential approach to improve clinical outcome.

METHODS

HTG Edge-seq was used to identify the differential gene expression between primary SCLC lesions and paired metastatic lymph nodes (LN). Overall survival (OS) analysis was performed in patients with different levels of plasma CCL19 concentration. Invasion, migration, proliferation, apoptosis and angiogenesis ability of SCLC cells and function of CD8 + T cells were evaluated in vitro to investigate the mechanism of CCL19 in promoting metastasis.

RESULTS

Four chemokines (CCL19, CCL21, CCL8, CCR1) were the most differentially expressed between primary lesions and metastatic LN. CCL19 was further investigated because its mRNA and protein level expression were also validated in four SCLC cell lines (H446, H69, H82, H196). Higher plasma CCL19 was associated with late lymph node (N3) metastasis (training cohort P = 0.044, validation cohort P = 0.020) and shorter OS (training cohort P = 0.040, validation cohort P = 0.047) in SCLC patients. Silencing CCL19 inhibited SCLC cell migration, invasion, proliferation and HUVECs tube formation. Furthermore, we found that CCL19 could decrease percentage of CD8 + Ki67 + and CD8 + GZMB + T cells and increase proportion of CD8 + PD1 + T cells.

CONCLUSION

CCL19 was associated with LN metastasis and poor prognosis in patients with SCLC. Its expression promoted tumor progression and metastasis and impaired the function of CD8 + T cells, suggesting CCL19 might be a potential target for SCLC.

[Analysis of Correlation between TTF-1 and Sensitivity to First-line Chemotherapy and Prognosis in Patients with Small Cell Lung Cancer]

背景与目的

甲状腺转录因子-1（thyroid transcription factor-1, TTF-1）在非小细胞肺癌中被广泛研究，被认为是非小细胞肺癌的独立预后因子，但TTF-1在小细胞肺癌（small cell lung cancer, SCLC）中的预后价值研究较少。本研究旨在探讨TTF-1的表达状态与SCLC患者一线化疗敏感性及预后的关系。

方法

回顾性分析2017年1月1日-2019年1月1日在青岛大学附属医院确诊并治疗的、一线应用以铂类为基础的化疗的SCLC患者234例，随访患者临床特征及治疗、生存情况，采用χ²检验及Logistic回归模型分析TTF-1的表达状况与化疗反应率的关系，Kaplan-Meier法和Cox比例风险回归模型分析TTF-1的表达对患者生存期的影响。

结果

234例患者中，TTF-1阳性表达188例（80.3%, 188/234），TTF-1阴性表达46例（19.7%, 46/234），TTF-1阳性患者一线化疗客观反应率（objective response rate, ORR）高于阴性患者（70.7% vs 47.8%）（χ²=8.681, P=0.003）。Logistic回归多因素分析显示，TTF-1的表达是一线化疗ORR的独立预测因素（OR=0.216, 95%CI: 0.076-0.615, P=0.004），但此差异仅体现在局限期SCLC（limited-stage SCLC, LS-SCLC）中。TTF-1阴性表达患者中位无进展生存期（progression free survival, PFS）6.9个月短于TTF-1阳性表达患者的9.0个月（χ²=9.357, P=0.002）。TTF-1阴性组患者中位总生存期（overall survival, OS）13.3个月短于TTF-1阳性组患者的20.1个月（χ²=12.082, P=0.001）。

结论

TTF-1表达状态为SCLC患者一线化疗反应率及生存的独立预测因素，可能成为预测SCLC治疗疗效及预后的生物标志物。

High-Risk Human Papillomavirus and Tobacco Smoke Interactions in Epithelial Carcinogenesis

Cervical, anogenital, and some head and neck cancers (HNC) are etiologically associated with high-risk human papillomavirus (HR-HPV) infection, even though additional cofactors are necessary. Epidemiological studies have established that tobacco smoke (TS) is a cofactor for cervical carcinogenesis because women who smoke are more susceptible to cervical cancer when compared to non-smokers. Even though such a relationship has not been established in HPV-related HNC, a group of HPV positive patients with this malignancy are smokers. TS is a complex mixture of more than 4500 chemical compounds and approximately 60 of them show oncogenic properties such as benzo[α]pyrene (BaP) and nitrosamines, among others. Some of these compounds have been evaluated for carcinogenesis through experimental settings in collaboration with HR-HPV. Here, we conducted a comprehensive review of the suggested molecular mechanisms involved in cooperation with both HR-HPV and TS for epithelial carcinogenesis. Furthermore, we propose interaction models in which TS collaborates with HR-HPV to promote epithelial cancer initiation, promotion, and progression. More studies are warranted to clarify interactions between oncogenic viruses and chemical or physical environmental factors for epithelial carcinogenesis.

Effects of peroxiredoxin 1 on nicotine induced apoptosis in mouse tongue

Local action of nicotine on oral mucosa contributes to the pathogenesis of precancerous and cancerous lesions. Nicotine participation in the mechanism of apoptosis in normal mucosa has not been established. Peroxiredoxin 1 (Prx1) is a cellular antioxidant that participates in regulating apoptosis. We investigated expression of Prx1 and proteins in apoptosis-related downstream signaling by mitogen-activated protein kinases (MAPKs) in nicotine-treated tongue tissues of wild-type and Prx1 knockout (Prx1^±) mice; we also investigated these processes in mouse embryonic fibroblast (MEF) cells in vitro. Nicotine increased the expression of Prx1 mRNA in tongue tissues in vivo. The rate of apoptosis was similar among the nicotine-treated mice, nicotine-treated + Prx1^± mice and untreated controls. The expression of p-JNK was greater in Prx1^± mice compared to control mice. In MEF cells, nicotine increased the expression of Prx1 and inhibited apoptosis and expression of p-p38 and p-JNK. Prx1 knockdown animals exhibited increased apoptotic rate and expression of p-p38 and p-JNK in MEFs. Nicotine-regulated apoptosis might occur via a Prx1-dependent pathway.

The Influence of Nicotine on Lung Tumor Growth, Cancer Chemotherapy, and Chemotherapy-Induced Peripheral Neuropathy

Studies in animal models have suggested that nicotine, an agonist of nicotinic acetylcholine receptors, may have the potential to prevent and/or reverse the peripheral neuropathy induced by cancer chemotherapeutic drugs, such as paclitaxel and oxaliplatin. However, a large body of evidence suggests that nicotine may also stimulate lung tumor growth and/or interfere with the effectiveness of cancer chemotherapy. Whereas the reported proliferative effects of nicotine are highly variable, the antagonism of antitumor drug efficacy is more consistent, although this latter effect has been demonstrated primarily in cell culture studies. In contrast, in vitro and in vivo studies from our own laboratory indicate that nicotine fails to enhance the growth of nonsmall cell lung cancer cells or attenuate the effects of chemotherapy (paclitaxel). Given the inconsistencies in the literature, coupled with our own findings, the weight of evidence suggests that caution may be warranted in proposing to use nicotine to mitigate chemotherapy-induced peripheral neuropathy in cancer patients receiving chemotherapy. Conversely, clinical trials could be performed in patients who have completed therapy and are considered to be disease-free to determine whether nicotine, in the form of commercially available patches or gum, is effective in alleviating peripheral neuropathy symptoms.

Duration-dependent effects of nicotine exposure on growth and AKT activation in human kidney epithelial cells

Exposure to nicotine is known to cause adverse effects in many target organs including kidney. Epidemiological studies suggest that nicotine-induced kidney diseases are prevalent worldwide. However, the impact of duration of exposure on the nicotine-induced adverse effects in normal kidney cells and the underlying molecular mechanism is still unclear. Hence, the objective of this study was to evaluate both acute and long-term effects of nicotine in normal human kidney epithelial cells (HK-2). Cells were treated with 1 and 10 µM nicotine for acute and long-term duration. The result of cell viability showed that the acute exposure to 1 µM nicotine has no significant effect on growth. However, the 10 µM nicotine caused significant decrease in the growth of HK-2 cells. The long-term exposure resulted in significantly increased cell growth in both 1 and 10 µM nicotine-treated groups. Analysis of cell cycle and expression of marker genes related to proliferation and apoptosis further confirmed the effects of nicotine. Additionally, the analysis of growth signaling pathway revealed the decreased level of pAKT in cells with acute exposure whereas the increased level of pAKT in long-term nicotine-exposed cells. This suggests that nicotine, through modulating the AKT pathway, controls the duration-dependent effects on the growth of HK-2 cells. In summary, this is the first report showing long-duration exposure to nicotine causes increased proliferation of human kidney epithelial cells through activation of AKT pathway.

Inflammation-Generated Extracellular Matrix Fragments Drive Lung Metastasis

Mechanisms explaining the propensity of a primary tumor to metastasize to a specific site still need to be unveiled, and clinical studies support a link between chronic inflammation and cancer dissemination to specific tissues. Using different mouse models, we demonstrate the role of inflammation-generated extracellular matrix fragments ac-PGP (N-acetyl-proline-glycine-proline) on tumor cells dissemination to lung parenchyma. In mice exposed to cigarette smoke or lipopolysaccharide, lung neutrophilic inflammation produces increased levels of MMP-9 (matrix metalloproteinase 9) that contributes to collagen breakdown and allows the release of ac-PGP tripeptides. By silencing CXCR2 gene expression in tumor cells, we show that these generated ac-PGP tripeptides exert a chemotactic activity on tumor cells in vivo by binding CXCR2.

Small Cell Lung Cancer

Small cell lung cancer (SCLC) is an aggressive cancer of neuroendocrine origin, which is strongly associated with cigarette smoking. Patients typically present with a short duration of symptoms and frequently (60-65 %) with metastatic disease. SCLC is a heterogeneous disease including extremely chemosensitive and chemoresistant clones. For this reason, a high percentage of patients respond to first-line chemotherapy but rapidly succumb to the disease. SCLC is generally divided into two stages, limited and extensive. Standard treatment of limited stage disease includes combination chemotherapy with cisplatin and etoposide for four cycles, thoracic radiation initiated early with the first cycle of chemotherapy, and consideration of prophylactic cranial irradiation (PCI) in the subset of patients with good response. Surgery may play a role in TNM stages I and II. In extensive disease, platinum agents and etoposide, used in combination, are again the first-line standard of care in the USA. However, thoracic radiation therapy is used predominately in patients where local control is important and PCI is of uncertain benefit. Despite these treatments, prognosis remains poor and novel therapies are needed to improve survival in this disease.

Pyrazine, 2-ethylpyridine, and 3-ethylpyridine are cigarette smoke components that alter the growth of normal and malignant human lung cells, and play a role in multidrug resistance development

Lung cancer is one of the few human diseases for which the primary etiological agent, cigarette smoke (CS), has been described; however, the precise role of individual cigarette smoke toxicant in tumor development and progression remains to be elusive. The purpose of this study was to assess in vitro the effects of previously identified cigarette smoke components, pyrazine, 2-ethylpyridine, and 3-ethylpyridine, on non-tumorigenic (MRC5) and adenocarcinomic (A549) human lung cell lines. Our data showed that the administration of three cigarette smoke components in combination perturbed the proliferation of both normal and adenocarcinomic cells. Study of malignant cells revealed that CS components were cytotoxic at high concentration (10(-6) M) and stimulatory in a dose-dependent manner at lower concentrations (10(-8) M to 10(-10) M). This adverse effect was enhanced when adenocarcinomic cells were maintained in hypoxia resembling intratumoral environment. Furthermore, exposure to pyrazine, 2-ethylpyridine, and 3-ethylpyridine induced oxidative stress in both normal and malignant cells. Finally, assessment of P-gp activity revealed that multidrug resistance was induced in CS component exposed adenocarcinomic lung cells and the induction was augmented in hypoxia. Taken together, pyrazine, 2-ethylpyridine, and 3-ethylpyridine adversely altered both normal and diseased lung cells in vitro and data collected from this study may help lung cancer patients to understand the importance of quitting smoking during lung cancer treatment.

Combined targeting of TGF-β1 and integrin β3 impairs lymph node metastasis in a mouse model of non-small-cell lung cancer

Background

Transforming Growth Factor beta (TGF-β) acts as a tumor suppressor early in carcinogenesis but turns into tumor promoter in later disease stages. In fact, TGF-β is a known inducer of integrin expression by tumor cells which contributes to cancer metastatic spread and TGF-β inhibition has been shown to attenuate metastasis in mouse models. However, carcinoma cells often become refractory to TGF-β-mediated growth inhibition. Therefore identifying patients that may benefit from anti-TGF-β therapy requires careful selection.

Methods

We performed in vitro analysis of the effects of exposure to TGF-β in NSCLC cell chemotaxis and adhesion to lymphatic endothelial cells. We also studied in an orthotopic model of NSCLC the incidence of metastases to the lymph nodes after inhibition of TGF-β signaling, β3 integrin expression or both.

Results

We offer evidences of increased β3-integrin dependent NSCLC adhesion to lymphatic endothelium after TGF-β exposure. In vivo experiments show that targeting of TGF-β and β3 integrin significantly reduces the incidence of lymph node metastasis. Even more, blockade of β3 integrin expression in tumors that did not respond to TGF-β inhibition severely impaired the ability of the tumor to metastasize towards the lymph nodes.

Conclusion

These findings suggest that lung cancer tumors refractory to TGF-β monotherapy can be effectively treated using dual therapy that combines the inhibition of tumor cell adhesion to lymphatic vessels with stromal TGF-β inhibition.

Smoking and postoperative outcomes in elective cranial surgery

Object

The goal in this study was to assess whether a current or prior history of smoking and the number of smoking pack years affect the risk for adverse outcomes in the 30-day postoperative period in patients who undergo elective cranial surgery.

Methods

Data from the 2006–2011 American College of Surgeons' National Surgical Quality Improvement Project were used in this study. The authors identified 8296 patients who underwent elective cranial surgery, of whom 1718 were current smokers, 854 were prior smokers, and 5724 were never smokers. Using propensity scores and age, the authors matched current and prior smokers to never smokers. Odds ratios for adverse postoperative outcomes were predicted with logistic regression. The relationship between number of pack years and poor outcomes was also examined.

Results

In unadjusted analyses, prior and current smokers did not differ from never smokers for having poor outcomes postoperatively. Similarly, in matched analyses, no association was found between smoking and adverse outcomes. Number of pack years in propensity-matched analyses did not predict worse outcomes in prior or current smokers versus never smokers.

Conclusions

The authors did not find smoking to be associated with 30-day postoperative morbidity or mortality. Although smoking cessation is beneficial for overall health, it may not improve the short-term (≤ 30 days) outcome of elective cranial surgery. Thus postponement of elective cranial cases only for smoking cessation may not be necessary.

[Second-line chemotherapy and its survival analysis of 181 patients with extensive-stage small cell lung cancer in a single institute]

BACKGROUND AND OBJECTIVE

Small cell lung cancer (SCLC) is the most malignant neuroendocrine tumor and sensitive to chemotherapy and radiotherapy. However, most patients who receive first-line chemotherapy will relapse within one to two years. Once recurrent, it indicates poor prognosis. Currently, the standard first-line chemotherapy regimen of extensive-stage SCLC is platinum combined etoposide regimen while the standard second-line chemotherapy regimen is open to debate. The aim of this study is to analysis the prognostic factors of second-line chemotherapy in extensive-stage SCLC and to compare the differences of objective response rate, side effects and survival among different second-line chemotherapy regimens.

METHODS

181 patients who were diagnosed as extensive-stage SCLC and received second-line chemotherapy were collected. χ(2) test was used to analysis the differences of enumeration data and between different groups. Kaplan-Meier method was used to calculate the overall survival (OS) and progression-free survival (PFS). Univariate analysis and Cox regression analysis were used to detect the prognostic factors. Objective response rate was evaluated by RECIST criteria and side effects were evaluated by WHO criteria.

RESULTS

The patients who received second-line chemotherapy can be divided into 6 groups, namly group A (CE/EP regimen) 27 cases, group B (regimens containing TPT) 44 cases, group C (regimens containing CPT-11) 33 cases, group D (regimens containing TAX/DXL) 20 cases, group E (regimens containing IFO) 28 cases and group F (other regimens) 29 cases. The median OS in second-line chemotherapy as 7.0 months and was relevant with smoking history (P=0.004), ECOG PS (P<0.001), liver metastasis (P=0.019) and bone metastasis (P=0.028) independently. The median PFS in second-line chemotherapy as 3.0 months and was relevant with smoking history (P=0.034), ECOG PS (P=0.011) and bone metastasis (P=0.005). The response rate among six regimens was significantly different (P=0.017); There was not statistical significance between each group. As to side effects, the incidence of gastrointestinal reaction in group C was higher than any other group. The differences of OS and PFS between six regimens in second-line therapy were not statistically different (P=0.914, P=0.293).

CONCLUSIONS

The most significant prognostic factor of extensive-stage small cell lung cancer patients who received second-line chemotherapy was ECOG PS. The most optimal second-line chemotherapy regimen with definite curatice effect was controversial.

The impact of smoking on neurosurgical outcomes

Cigarette smoking is a common health risk behavior among the general adult population, and is the leading preventable cause of morbidity and mortality in the US. The surgical literature shows that active tobacco smoking is a major risk factor for perioperative morbidity and complications, and that preoperative smoking cessation is an effective measure to lower these risks associated with active smoking. However, few studies have examined the effects of smoking and perioperative complications following neurosurgical procedures. The goal of this review was to highlight the scientific data that do exist regarding the impact of smoking on neurosurgical outcomes, to promote awareness of the need for further work in the specific neurosurgical context, and to suggest ways that neurosurgeons can promote smoking cessation in their patients and lead efforts nationally to emphasize the importance of preoperative smoking cessation. This review indicates that there is limited but good evidence that smoking is associated with higher rates of perioperative complications following neurosurgical intervention. Specific research is needed to understand the effects of smoking and perioperative complications. Neurosurgeons should encourage preoperative smoking cessation as part of their clinical practice to mitigate perioperative morbidity associated with active smoking.

Targets in small cell lung cancer

Recurrent small cell lung cancer is a recalcitrant malgnancy. The application of genomic technologies has begun to elucidate the large number of genetic abnormalities in SCLC. Several cell surface receptors are known to be overexpressed by SCLC in clinic specimens and cell in culture including GPCRs such as the bradykinin receptor, the chemokine receptor CXCR4, the vasopression receeptor and the three bomebsin receptors. The glucose transporter GLUT1, the tetraspanin family member PETA/CD151 and the immunoglobulin superfamily member ALCAM/CD166 are also overexpressed by SCLC. NCAM/CD56 is overexpressed by nearly all SCLC and is currently the target for an antibody drug conjugate in Phase II trial. Although SCLC is not considered a RTK driven disease, IGF1R and FGFRs are often overexpressed by SCLC. SCLC abberantly expresses several developmental transcription factors including ASCL1, SOX2, 4, and 11, OCT4, NANOG, PAX5; however, overexpression of MYC may be a driver in SCLC. Like other cancers, SCLC expresses survival factors and uses aerobic glycolysis as a major source of ATP. The drawback of many potential targets overexpressed by SCLC is expression of the same proteins by normal tissues. We are slowly learning more about the molecular abnormalities that occur in SCLC; however, therapeutic impact from new findings remains a goal to work toward.

The small cell lung cancer-specific isoform of RE1-silencing transcription factor (REST) is regulated by neural-specific Ser/Arg repeat-related protein of 100 kDa (nSR100)

Small cell lung cancer (SCLC) is a highly malignant form of cancer, which originates from primitive neuroendocrine cells in the lung. SCLC cells express several autocrine neurotransmitters/neuropeptides and their respective receptors. Expression of these neuronal markers is frequently regulated by RE1-silencing transcription factor (REST). In SCLC cells, an SCLC-specific isoform of REST (sREST) is highly expressed, whereas REST expression is undetectable, suggesting that the expression of sREST correlates with the pathogenesis of SCLC. Expression of sREST, which is derived through alternative splicing of REST, is abnormally regulated in SCLC cells, but the mechanism is unknown. Most recently, nSR100 (SRRM4) was described as an activator of REST alternative splicing. We now show that nSR100 is highly expressed in SCLC cells correlating with high sREST and low REST expression. Adhesion to the extracellular matrix (ECM) is thought to enhance tumorigenicity and confer resistance to apoptosis. Interestingly, nSR100 expression is enhanced in cells grown with ECM. Overexpression of REST caused repression of sREST and nSR100, the latter containing RE1 element controlled by REST. Culturing the SCLC cell line NCI-N417 cells with ECM also upregulated RE1-containing gene, the voltage-gated calcium channel subunit. Inhibition of the PI3K/Akt/mTOR pathway by LY294002 induced nSR100 expression, whereas the specific MEK/ERK inhibitor U0126 inhibited nSR100 expression. Repressing nSR100 by siRNA effectively repressed sREST, and conversely increased REST in NCI-N417 cells. Taken together, this report clarifies the ECM-dependent signaling pathway that impacts nSR100 expression and its regulation of alternative splicing in SCLC.

IMPLICATIONS

The splicing factor nSR100 may be novel SCLC-specific biomarker, as well as a therapeutic target.

Nicotine induces inhibitor of differentiation-1 in a Src-dependent pathway promoting metastasis and chemoresistance in pancreatic adenocarcinoma

Smoking is a significant risk factor for pancreatic cancer, but the molecular mechanisms by which tobacco smoke components promote the growth and progression of these cancers are not fully understood. While nicotine, the addictive component of tobacco smoke, is not a carcinogen, it has been shown to promote the growth of non-small cell lung and pancreatic cancers in a receptor-dependent fashion. Here, we show that stimulation of pancreatic cancer cells with nicotine concentrations that are within the range of human exposure results in activation of Src kinase, which facilitated the induction of the inhibitor of differentiation-1 (Id1) transcription factor. Depletion of Id1 prevented nicotine-mediated induction of proliferation and invasion of pancreatic cancer cells, indicating that it is a major mediator of nicotine function. Nicotine could promote the growth and metastasis of pancreatic cancers orthotopically implanted into SCID mice; in addition, cells stably expressing a short hairpin RNA for Id1 did not grow or metastasize in response to nicotine. Nicotine could also confer resistance to apoptosis induced by gemcitabine in pancreatic cancer cells in vitro and depletion of Src or Id1 rendered the cells sensitive to gemcitabine. Further, nicotine could effectively inhibit the chemotherapeutic effects of gemcitabine on pancreatic tumors xenografted into mice. Clinical analyses of resected pancreatic cancer specimens demonstrated a statistically significant correlation between Id1 expression and phospho-Src, tumor grade/differentiation, and worsening overall patient survival. These results demonstrate that exposure to tobacco smoke components might promote pancreatic cancer progression, metastasis, and chemoresistance and highlight the role of Id1 in these processes.

New molecular insights in tobacco-induced lung cancer

We know that cigarette smoking is a leading preventable cause of carcinogenesis in lung cancer. Cigarette smoke is a mixture of more than 5000 chemical compounds, among which more than 60 are recognized to have a specific carcinogenic potential. Carcinogens and their metabolites (i.e., N-nitrosamines and polycyclic aromatic hydrocarbons) can activate multiple pathways, contributing to lung cell transformation in different ways. Nicotine, originally thought only to be responsible for tobacco addiction, is also involved in tumor promotion and progression with antiapoptotic and indirect mitogenic properties. Lung nodules are frequent in smokers and can be transformed into malignant tumors depending on persistant smoking status. Even if detailed mechanisms underlying tobacco-induced cancerogenesis are not completely elucitated, this report collects the emergent body of knowledge in order to simplify the extremely complex framework that links smoking exposure to lung cancer.

Concomitant overexpression of EGFR and CXCR4 is associated with worse prognosis in a new molecular subtype of non-small cell lung cancer

Although the relationships between CXCR4 and EGFR expression and survival in non‑small cell lung cancer (NSCLC) have been studied independently, dual CXCR4/EGFR tumor status and its relationship with survival has not been previously investigated. In the present study, we examined the relationship between CXCR4 expression, EGFR expression and dual CXCR4/EGFR expression and survival in patients with NSCLC (n=125) using immunohistochemical techniques. Overall survival was estimated using Kaplan-Meier and Cox proportional hazards models adjusting for patient age, tumor stage and type of treatments. Patients with CXCR4-positive tumors were significantly associated with distant metastasis and tended to have poorer prognosis compared to patients with CXCR4-negative tumors (HR=2.172, 95% CI=1.229‑3.839). No significant association between EGFR expression and survival was found; however co-expression of CXCR4/EGFR was a significant prognostic factor of worse overall survival (HR=2.741, 95% CI=1.330‑5.741). Furthermore, we showed that EGF enhanced the expression of CXCR4 in NSCLC cells through the PI-3K pathway, and treatment of NSCLC cells with EGFR phosphorylation inhibitor, AG1478, resulted in downregulation of the expression of CXCR4. These results suggest an important interaction between CXCR4 and EGFR intra-cellular pathways that may activate signals of tumor progression and may provide a valid explanation for the poor overall survival rate of patients whose co-expression of CXCR4 and EGFR is detected in tissue sections. Based on EGFR and CXCR4 expression, new molecular subtypes of NSCLC established in the present study can be used for customization of NSCLC treatment. Our results also showed that EGFR and CXCR4 are potential therapeutic targets for NSCLC and that simultaneous inhibition of EGFR and CXCR4 in NSCLC patients with concomitant expression of both CXCR4 and EGFR may be an effective treatment strategy.

Silencing of periostin inhibits nicotine-mediated tumor cell growth and epithelial-mesenchymal transition in lung cancer cells

Nicotine has been found to induce the proliferation of lung cancer cells through tumor invasion and to confer resistance to apoptosis. Periostin is abnormally highly expressed in lung cancer and is correlated with angiogenesis, invasion and metastasis. Here, we investigated the roles of periostin in the lung cancer cell proliferation, drug resistance, invasion and epithelial-mesenchymal transition (EMT) induced by nicotine. The periostin gene was silenced using small interfering RNA (siRNA) in A549 non-small cell lung cancer (NSCLC) cells. The cells were transfected with control or periostin siRNA plasmids. Periostin mRNA was evaluated by quantitative reverse transcription-polymerase chain reaction (RT-PCR). Cell proliferation was detected using the MTT assay and cell apoptosis was detected by Annexin V-FITC and propidium iodide (PI) double staining. Tumor invasion was detected by the Boyden chamber invasion assay. Western blotting was performed to detect the expression of the EMT marker Snail. Our results revealed that stably periostin-silenced cells were acquired by G418 screening, and the periostin mRNA expression levels of which were decreased by nearly 80%. Periostin-silenced A549 cells exhibited reduced cell proliferation, elevated sensitivity to chemotherapy with cisplatin, decreased cell invasion and Snail expression (P<0.05). Nicotine upregulated the periostin protein levels in the A549 cells and this upregulation was not blocked by the generalized nicotinic acetylcholine receptor (nAChR) antagonist, hexamethonium. In conclusion, periostin is one of the targets regulated by nicotine in lung cancer cells and is involved in the cancer cell growth, drug resistance, invasion and EMT induced by nicotine.

Cigarette smoking: a risk factor for postoperative morbidity and 1-year mortality following craniotomy for tumor resection

Object

Identifying risk factors for surgical morbidity and mortality might improve the safety and efficacy of neurosurgical intervention. Cigarette smoking is a relatively common practice and is associated with several adverse health outcomes. The authors examined the relationship between smoking and intraoperative blood loss, postoperative outcomes, and survival following craniotomy for tumor resection.

Methods

A consecutive population of patients undergoing craniotomy for tumor resection between 2006 and 2009 was identified. Using multivariable models and Cox proportional hazard regression analysis, the authors assessed the relation between smoking and operative outcomes including blood loss, complication rates, hospital length of stay, 30-day mortality, and 1-year survival among patients who underwent craniotomy for tumor resection.

Results

A total of 453 patients were included in this study: 237 patients never smoked, 54 quit smoking for at least 1 year, and 162 were current smokers. Current smoking status was an independent risk factor for higher intraoperative blood loss, complication risk, and lower 1-year survival following intervention relative to patients who never smoked. Patients who quit smoking had significantly higher mean blood loss, but did not carry a higher risk for other outcomes such as postoperative complications and 1-year mortality compared with patients who never smoked.

Conclusions

Current cigarette smoking is associated with poor surgical outcome and lower 1-year survival after undergoing craniotomy for tumor resection. However, quitting smoking and implementing strict smoking cessation programs may help mitigate these risks. Future research might investigate mechanisms underlying these associations.

MG624, an α7-nAChR antagonist, inhibits angiogenesis via the Egr-1/FGF2 pathway

Small cell lung cancer (SCLC) demonstrates a strong etiological association with smoking. Although cigarette smoke is a mixture of about 4,000 compounds, nicotine is the addictive component of cigarette smoke. Several convergent studies have shown that nicotine promotes angiogenesis in lung cancers via the α7-nicotinic acetylcholine receptor (α7-nAChR) on endothelial cells. Therefore, we conjectured that α7-nAChR antagonists may attenuate nicotine-induced angiogenesis and be useful for the treatment of human SCLC. For the first time, our study explores the anti-angiogenic activity of MG624, a small-molecule α7-nAChR antagonist, in several experimental models of angiogenesis. We observed that MG624 potently suppressed the proliferation of primary human microvascular endothelial cells of the lung (HMEC-Ls). Furthermore, MG624 displayed robust anti-angiogenic activity in the Matrigel, rat aortic ring and rat retinal explant assays. The anti-angiogenic activity of MG624 was assessed by two in vivo models, namely the chicken chorioallantoic membrane model and the nude mice model. In both of these experimental models, MG624 inhibited angiogenesis of human SCLC tumors. Most importantly, the administration of MG624 was not associated with any toxic side effects, lethargy or discomfort in the mice. The anti-angiogenic activity of MG624 was mediated via the suppression of nicotine-induced FGF2 levels in HMEC-Ls. MG624 decreased nicotine-induced early growth response gene 1 (Egr-1) levels in HMEC-Ls, and reduced the levels of Egr-1 on the FGF2 promoter. Consequently, this process decreased FGF2 levels and angiogenesis. Our findings suggest that the anti-angiogenic effects of MG624 could be useful in anti-angiogenic therapy of human SCLCs.

The use of in vitro systems to assess cancer mechanisms and the carcinogenic potential of chemicals

Carcinogenesis is a highly complex, multi-stage process that can occur over a relatively long period before its clinical manifestation. While the sequence in which a cancer cell acquires the necessary traits for tumour formation can vary, there are a number of mechanisms that are common to most, if not all, cancers across the spectrum of possible causes. Many aspects of carcinogenesis can be modelled in vitro. This has led to the development of a number of mechanistically driven, cell-based assays to assess the pro-carcinogenic and anti-carcinogenic potential of chemicals. A review is presented of the current in vitro models that can be used to study carcinogenesis, with examples of cigarette smoke testing in some of these models, in order to illustrate their potential applications. We present an overview of the assays used in regulatory genotoxicity testing, as well as those designed to model other aspects that are considered to be hallmarks of cancer. The latter assays are described with a view to demonstrating the recent advances in these areas, to a point where they should now be considered for inclusion in an overall testing strategy for chemical carcinogens.

Treatment and survival of patients with small-cell lung cancer: small steps forward, but not for patients >80

BACKGROUND

Seventy-five percent of newly diagnosed patients with small-cell lung cancer (SCLC) are aged 60+ and quite a few are treated less aggressively because of fear of toxic effects. We described trends in treatment and survival of unselected SCLC patients.

PATIENTS AND METHODS

For the present study, all 13,007 SCLC patients aged 60+ diagnosed in The Netherlands from 1997 to 2007 were included.

RESULTS

Among patients with limited disease, the proportion receiving chemoradiation increased from 35% to almost 60% for those aged 60-69, from 28% to 48% in age group 70-74, from 17% to 33% in age group 75-79, but remained <10% for those aged 80+. Among patients with extensive disease, the proportion receiving chemotherapy (CT) decreased from 81% of patients aged 60-64 to 23% of those aged 85+, without substantial changes over time. Survival has only improved for patients <80 years.

CONCLUSIONS

CT (+radiotherapy) has improved survival for unselected SCLC patients <80. A better understanding of the impact of frailty on completion of treatment and toxic effects among patients aged 80+ would enable the treating physician to anticipate toxic effects better and to discuss risks and benefits of treatment with the patient.

Nicotinic acetylcholine receptor signaling in tumor growth and metastasis

Cigarette smoking is highly correlated with the onset of a variety of human cancers, and continued smoking is known to abrogate the beneficial effects of cancer therapy. While tobacco smoke contains hundreds of molecules that are known carcinogens, nicotine, the main addictive component of tobacco smoke, is not carcinogenic. At the same time, nicotine has been shown to promote cell proliferation, angiogenesis, and epithelial-mesenchymal transition, leading to enhanced tumor growth and metastasis. These effects of nicotine are mediated through the nicotinic acetylcholine receptors that are expressed on a variety of neuronal and nonneuronal cells. Specific signal transduction cascades that emanate from different nAChR subunits or subunit combinations facilitate the proliferative and prosurvival functions of nicotine. Nicotinic acetylcholine receptors appear to stimulate many downstream signaling cascades induced by growth factors and mitogens. It has been suggested that antagonists of nAChR signaling might have antitumor effects and might open new avenues for combating tobacco-related cancer. This paper examines the historical data connecting nicotine tumor progression and the recent efforts to target the nicotinic acetylcholine receptors to combat cancer.

Small-cell lung cancer-associated autoantibodies: potential applications to cancer diagnosis, early detection, and therapy

Small-cell lung cancer (SCLC) is the most aggressive lung cancer subtype and lacks effective early detection methods and therapies. A number of rare paraneoplastic neurologic autoimmune diseases are strongly associated with SCLC. Most patients with such paraneoplastic syndromes harbor high titers of antibodies against neuronal proteins that are abnormally expressed in SCLC tumors. These autoantibodies may cross-react with the nervous system, possibly contributing to autoimmune disease development. Importantly, similar antibodies are present in many SCLC patients without autoimmune disease, albeit at lower titers. The timing of autoantibody development relative to cancer and the nature of the immune trigger remain to be elucidated. Here we review what is currently known about SCLC-associated autoantibodies, and describe a recently developed mouse model system of SCLC that appears to lend itself well to the study of the SCLC-associated immune response. We also discuss potential clinical applications for these autoantibodies, such as SCLC diagnosis, early detection, and therapy.

Epigenetic effects and molecular mechanisms of tumorigenesis induced by cigarette smoke: an overview

Cigarette smoking is one of the major causes of carcinogenesis. Direct genotoxicity induced by cigarette smoke leads to initiation of carcinogenesis. Nongenotoxic (epigenetic) effects of cigarette smoke also act as modulators altering cellular functions. These two effects underlie the mechanisms of tumor promotion and progression. While there is no lack of general reviews on the genotoxic and carcinogenic potentials of cigarette smoke in lung carcinogenesis, updated review on the epigenetic effects and molecular mechanisms of cigarette smoke and carcinogenesis, not limited to lung, is lacking. We are presenting a comprehensive review of recent investigations on cigarette smoke, with special attentions to nicotine, NNK, and PAHs. The current understanding on their molecular mechanisms include (1) receptors, (2) cell cycle regulators, (3) signaling pathways, (4) apoptosis mediators, (5) angiogenic factors, and (6) invasive and metastasis mediators. This review highlighted the complexity biological responses to cigarette smoke components and their involvements in tumorigenesis.