Reciprocal activation of α5-nAChR and STAT3 in nicotine-induced human lung cancer cell proliferation

Spinosad blocks CHRNA5 mediated EGFR signaling pathway activation to inhibit lung adenocarcinoma proliferation

Lung adenocarcinoma (LUAD) is the leading cause of cancer death worldwide, with high incidence and low survival rates. Nicotinic acetylcholine receptors play an important role in the progression of LUAD. In this study, a screening of 17 nicotinic acetylcholine receptor allosteric agents revealed that spinosad effectively suppressed the proliferation of LUAD cells. The experiments demonstrated that spinosad induced cell cycle arrest in the G1 phase and stimulated apoptosis, thereby impeding the growth of LUAD and enhancing the responsiveness to gefitinib in vitro and vivo. Mechanistic insights obtained through transcriptome sequencing, Co-IP, and protein immunoblots indicated that spinosad disrupted the interaction between CHRNA5 and EGFR, thereby inhibiting the formation of downstream complexes and activation of the EGFR signaling pathway. The supplementation of exogenous acetylcholine showed to mitigate the inhibition of LUAD cell proliferation induced by spinosad. This study elucidates the therapeutic effects and mechanisms of spinosad in LUAD, and offers a theoretical and experimental foundation for novel LUAD treatments.

Nicotine-induced activation of cholinergic receptor nicotinic alpha 5 subunit mediates the malignant behaviours of laryngeal squamous epithelial cells by interacting with RABL6

Nicotine, a crucial constituent of tobacco smoke, can bind to and activate nicotinic acetylcholine receptors (nAChRs), thereby regulating various biological functions. However, the specific mechanisms through which nicotine mediates nAChRs to regulate the metastasis of laryngeal squamous cell carcinoma (LSCC) remain elusive. In this study, smoking status was found to be closely associated with metastasis in patients with LSCC. In addition, nicotine exposure potentiated the hematogenous and lymphatic metastatic capacity of LSCC cells. Nicotine activates membrane-bound CHRNA5, promoting cell migration and invasion, EMT and cell-ECM adhesion in LSCC. Furthermore, this study demonstrated that the Ras superfamily protein RABL6 directly interacted with CHRNA5, which preferentially binds to the RABL6-39-279aa region, and this interaction was enhanced by nicotine. Nicotine-mediated activation of CHRNA5 enhanced its interaction with RABL6, triggering the JAK2/STAT3 signalling pathway and eventually augmenting the metastatic potential of LSCC cells. This study reveals a novel mechanism through which nicotine-mediated CHRNA5-RABL6 interaction promotes the metastasis of LSCC. The findings of this study may help to develop effective strategies for improving the outcome of patients with LSCC in clinical settings.

α5-nAChR/ADAM10 signaling mediates nicotine-related cutaneous melanoma progression via STAT3 activation

Skin cutaneous melanoma (SKCM) is the skin malignancy with the highest mortality rate, and its morbidity rate is on the rise worldwide. Smoking is an independent marker of poor prognosis in melanoma. The α5-nicotinic acetylcholine receptor (α5-nAChR), one of the receptors for nicotine, is involved in the proliferation, migration and invasion of SKCM cells. Nicotine has been reported to promote the expression of a disintegrin and metalloproteinase 10 (ADAM10), which is the key gene involved in melanoma progression. Here, we explored the link between α5-nAChR and ADAM10 in nicotine-associated cutaneous melanoma. α5-nAChR expression was correlated with ADAM10 expression and lower survival in SKCM. α5-nAChR mediated nicotine-induced ADAM10 expression via STAT3. The α5-nAChR/ADAM10 signaling axis was involved in the stemness and migration of SKCM cells. Furthermore, α5-nAChR expression was associated with ADAM10 expression, EMT marker expression and stemness marker expression in nicotine-related mice homograft tissues. These results suggest the role of the α5-nAChR/ADAM10 signaling pathway in nicotine-induced melanoma progression.

Cell signaling and epigenetic regulation of nicotine-induced carcinogenesis

Nicotine, a naturally occurring tobacco alkaloid responsible for tobacco addiction, has long been considered non-carcinogenic. However, emerging evidence suggests that nicotine may possess carcinogenic properties in mice and could be a potential carcinogen in humans. This review aims to summarize the potential molecular mechanisms underlying nicotine-induced carcinogenesis, with a specific focus on epigenetic regulation and the activation of nicotinic acetylcholine receptors (nAChRs) in addition to genotoxicity and excess reactive oxygen species (ROS). Additionally, we explore a novel hypothesis regarding nicotine's carcinogenicity involving the downregulation of stem-loop binding protein (SLBP), a critical regulator of canonical histone mRNA, and the polyadenylation of canonical histone mRNA. By shedding light on these mechanisms, this review underscores the need for further research to elucidate the carcinogenic potential of nicotine and its implications for human health.

The role of α7-nAChR-mediated PI3K/AKT pathway in lung cancer induced by nicotine

Nicotine enters the environment mainly through human activity, as well as natural sources. This review article examines the increasing evidence implicating nicotine in the initiation and progression of lung cancer. Moreover, it primarily focuses on elucidating the activation mechanism of phosphoinositide 3-kinase (PI3K)/protein kinase B (PKB, also known as AKT) signaling pathway, regulated by α7 subtype nicotinic acetylcholine receptor (α7-nAChR), in relation to the proliferation, invasion, and metastasis of lung cancer cells induced by nicotine, as well as nicotine-mediated anti-apoptotic effects. This process involves PI3K/AKT phosphorylated-B-cell lymphoma-2 (Bcl-2) family proteins, PI3K/AKT/mammalian target of rapamycin (mTOR), PI3K/AKT/nuclear factor-κB (NF-κB), hepatocyte growth factor (HGF)/cellular-mesenchymal epithelial transition factor (c-Met)-induced PI3K/AKT and PI3K/AKT activated-hypoxia-inducible factor-1α (HIF-1α)/vascular endothelial growth factor (VEGF) pathways. In addition, we also deliberated on the related challenges and upcoming prospects within this field. These lay the foundation for further study on nicotine, lung tumorigenesis, and PI3K/AKT related molecular mechanisms. This work has the potential to significantly contribute to the treatment and prognosis of gastric cancer in smokers. Besides, the crucial significance of PI3K/AKT signaling pathway in multiple molecular pathways also suggests that its target antagonists may inhibit the development and progression of lung cancer, providing a possible new perspective for solving the problem of nicotine-promoted lung cancer. The emerging knowledge about the carcinogenic mechanisms of nicotine action should be considered during the environmental assessment of tobacco and other nicotine-containing products.

Nicotinic acetylcholine receptor CHRNA5 is overexpressed in head and neck squamous cell carcinoma patients with a recent tobacco smoking history

Tobacco smoking is a major driver of head and neck squamous cell carcinoma (HNSCC) occurrence, and previous studies have shed light on the precise molecular alterations in tobacco-related HNSCCs when compared to HNSCCs associated with other risk factors (ex: human papillomavirus/HPV status). In this study, we analyzed the gene expression differences in HNSCC cases with a recent smoking history and revealed that the nicotinic acetylcholine receptor CHRNA5 is differentially overexpressed in smoking-related HNSCCs. CHRNA5 overexpression in these HNSCCs corresponds with a worse prognosis and is inversely correlated with an immune expression signature commonly associated with better prognosis. From these results, our study highlights the potential role of the nicotine-activated CHRNA5 receptor in HNSCC progression and corresponds with other recent reports highlighting the potential role of nicotine induction in promoting cancer progression.

PLEK2 mediates metastasis and invasion via α5-nAChR activation in nicotine-induced lung adenocarcinoma

Evidence has shown a strong relationship between smoking and epithelial mesenchymal transition (EMT). α5-nicotinic acetylcholine receptor (α5-nAChR) contributes to nicotine-induced lung cancer cell EMT. The cytoskeleton-associated protein PLEK2 is mainly involved in cytoskeletal protein recombination and cell stretch migration regulation, which is closely related to EMT. However, little is known about the link between nicotine/α5-nAChR and PLEK2 in lung adenocarcinoma (LUAD). Here, we identified a link between α5-nAChR and PLEK2 in LUAD. α5-nAChR expression was correlated with PLEK2 expression, smoking status and lower survival in vivo. α5-nAChR mediated nicotine-induced PLEK2 expression via STAT3. α5-nAChR/PLEK2 signaling is involved in LUAD cell migration, invasion and stemness. Moreover, PLEK2 was found to interact with CFL1 in nicotine-induced EMT in LUAD cells. Furthermore, the functional link among α5-nAChR, PLEK2 and CFL1 was confirmed in mouse xenograft tissues and human LUAD tissues. These findings reveal a novel α5-nAChR/PLEK2/CFL1 pathway involved in nicotine-induced LUAD progression.

Current Progress on Central Cholinergic Receptors as Therapeutic Targets for Alzheimer's Disease

Acetylcholine (ACh) is ubiquitously present in the nervous system and has been involved in the regulation of various brain functions. By modulating synaptic transmission and promoting synaptic plasticity, particularly in the hippocampus and cortex, ACh plays a pivotal role in the regulation of learning and memory. These procognitive actions of ACh are mediated by the neuronal muscarinic and nicotinic cholinergic receptors. The impairment of cholinergic transmission leads to cognitive decline associated with aging and dementia. Therefore, the cholinergic system has been of prime focus when concerned with Alzheimer's disease (AD), the most common cause of dementia. In AD, the extensive destruction of cholinergic neurons occurs by amyloid-β plaques and tau protein-rich neurofibrillary tangles. Amyloid-β also blocks cholinergic receptors and obstructs neuronal signaling. This makes the central cholinergic system an important target for the development of drugs for AD. In fact, centrally acting cholinesterase inhibitors like donepezil and rivastigmine are approved for the treatment of AD, although the outcome is not satisfactory. Therefore, identification of specific subtypes of cholinergic receptors involved in the pathogenesis of AD is essential to develop future drugs. Also, the identification of endogenous rescue mechanisms to the cholinergic system can pave the way for new drug development. In this article, we discussed the neuroanatomy of the central cholinergic system. Further, various subtypes of muscarinic and nicotinic receptors involved in the cognition and pathophysiology of AD are described in detail. The article also reviewed primary neurotransmitters that regulate cognitive processes by modulating basal forebrain cholinergic projection neurons.

Nicotinic acetylcholine receptors in cancer: Limitations and prospects

Nicotinic acetylcholine receptors (nAChRs) have long been considered to solely mediate neurotransmission. However, their widespread distribution in the human body suggests a more diverse physiological role. Additionally, the expression of nAChRs is increased in certain cancers, such as lung cancer, and has been associated with cell proliferation, epithelial-to-mesenchymal cell transition, angiogenesis and apoptosis prevention. Several compounds that interact with these receptors have been identified as potential therapeutic agents. They have been tested as drugs for treating nicotine addiction, alcoholism, depression, pain and Alzheimer's disease. This review focuses on nAChR-mediated signalling in cancer, presenting opportunities for the development of innovative nAChR-based anticancer drugs. It displays the differences in expression of each nAChR subunit between normal and cancer cells for selected cancer types, highlighting their possible involvement in specific cases. Antagonists of nAChRs that could complement existing cancer therapies are summarised and critically discussed. We hope that this review will stimulate further research on the role of nAChRs in cancer potentially leading to innovative cancer therapies.

Dysregulation of immunity by cigarette smoking promotes inflammation and cancer: A review

Smoking is a serious global health issue. Cigarette smoking contains over 7000 different chemicals. The main harmful components include nicotine, acrolein, aromatic hydrocarbons and heavy metals, which play the key role for cigarette-induced inflammation and carcinogenesis. Growing evidences show that cigarette smoking and its components exert a remarkable impact on regulation of immunity and dysregulated immunity promotes inflammation and cancer. Therefore, this comprehensive and up-to-date review covers four interrelated topics, including cigarette smoking, inflammation, cancer and immune system. The known harmful chemicals from cigarette smoking were summarized. Importantly, we discussed in depth the impact of cigarette smoking on the formation of inflammatory or tumor microenvironment, primarily by affecting immune effector cells, such as macrophages, neutrophils, and T lymphocytes. Furthermore, the main molecular mechanisms by which cigarette smoking induces inflammation and cancer, including changes in epigenetics, DNA damage and others were further summarized. This article will contribute to a better understanding of the impact of cigarette smoking on inducing inflammation and cancer.

α5-nAChR/STAT3/CD47 axis contributed to nicotine-related lung adenocarcinoma progression and immune escape

OBJECTIVES

The CHRNΑ5 gene, which encodes the α5-nicotinic acetylcholine receptor (α5-nAChR), is related to lung cancer and nicotine addiction. Smoking is closely related to the immunosuppressive effect of macrophages. CD47, a phagocytosis checkpoint in macrophages, is a therapeutic target in various cancer types. Nevertheless, the relationship between α5-nAChR and CD47 in lung cancer is still unclear.

METHODS AND RESULTS

The present study showed that α5-nAChR-mediated CD47 expression via STAT3 signaling, consequently leading to tumor progression and immune suppression in lung adenocarcinoma (LUAD). α5-nAChR expression was correlated with STAT3 expression, CD47 expression, smoking status and poor prognosis of LUAD in vivo. In vitro, α5-nAChR expression mediated the phosphorylation of STAT3, and phosphorylated STAT3 bound to the CD47 promoter and mediated CD47 expression. Downregulation of α5-nAChR and/or CD47 significantly reduced cell proliferation, migration, invasion, stemness and IL-10 expression, but increased TNF-α expression and phagocytosis of macrophages in LUAD. Furthermore, α5-nAChR/CD47 signaling contributed to the growth of subcutaneous xenograft tumors and liver metastasis of tumors in mice.

CONCLUSION

The α5-nAChR/STAT3/CD47 axis contributed to the progression and immune escape of lung cancer and may be a potential target for LUAD immunotherapy.

Ion channels in lung cancer: biological and clinical relevance

Despite improvements in treatment, lung cancer is still a major health problem worldwide. Among lung cancer subtypes, the most frequent is represented by adenocarcinoma (belonging to the Non-Small Cell Lung Cancer class) although the most challenging and harder to treat is represented by Small Cell Lung Cancer, that occurs at lower frequency but has the worst prognosis. For these reasons, the standard of care for these patients is represented by a combination of surgery, radiation therapy and chemotherapy. In this view, searching for novel biomarkers that might help both in diagnosis and therapy is mandatory. In the last 30 years it was demonstrated that different families of ion channels are overexpressed in both lung cancer cell lines and primary tumours. The altered ion channel profile may be advantageous for diagnostic and therapeutic purposes since most of them are localised on the plasma membrane thus their detection is quite easy, as well as their block with specific drugs and antibodies. This review focuses on ion channels (Potassium, Sodium, Calcium, Chloride, Anion and Nicotinic Acetylcholine receptors) in lung cancer (both Non-Small Cell Lung Cancer and Small Cell Lung Cancer) and recapitulate the up-to-date knowledge about their role and clinical relevance for a potential use in the clinical setting, for lung cancer diagnosis and therapy.

Contribution of the α5 nAChR Subunit and α5SNP to Nicotine-Induced Proliferation and Migration of Human Cancer Cells

Nicotine in tobacco is known to induce tumor-promoting effects and cause chemotherapy resistance through the activation of nicotinic acetylcholine receptors (nAChRs). Many studies have associated the α5 nicotinic receptor subunit (α5), and a specific polymorphism in this subunit, with (i) nicotine administration, (ii) nicotine dependence, and (iii) lung cancer. The α5 gene CHRNA5 mRNA is upregulated in several types of cancer, including lung, prostate, colorectal, and stomach cancer, and cancer severity is correlated with smoking. In this study, we investigate the contribution of α5 in the nicotine-induced cancer hallmark functions proliferation and migration, in breast, colon, and prostate cancer cells. Nine human cell lines from different origins were used to determine nAChR subunit expression levels. Then, selected breast (MCF7), colon (SW480), and prostate (DU145) cancer cell lines were used to investigate the nicotine-induced effects mediated by α5. Using pharmacological and siRNA-based experiments, we show that α5 is essential for nicotine-induced proliferation and migration. Additionally, upon downregulation of α5, nicotine-promoted expression of EMT markers and immune regulatory proteins was impaired. Moreover, the α5 polymorphism D398N (α5SNP) caused a basal increase in proliferation and migration in the DU145 cell line, and the effect was mediated through G-protein signaling. Taken together, our results indicate that nicotine-induced cancer cell proliferation and migration are mediated via α5, adding to the characterization of α5 as a putative therapeutical target.

Acetylcholine promotes chronic stress-induced lung adenocarcinoma progression via α5-nAChR/FHIT pathway

Chronic stress significantly elevates the expression levels of various neurotransmitters in the tumour microenvironment, thereby promoting the cell growth and metastasis of lung adenocarcinoma (LUAD). However, the role of chronic stress in the progression of LUAD remains unclear. In this study, we found that chronic restraint stress increases the levels of the neurotransmitter acetylcholine (ACh), and the α5-nicotinic acetylcholine receptor (α5-nAChR) and decreased fragile histidine triad (FHIT) expression in vivo. Crucially, the increased ACh levels promoted LUAD cell migration and invasion via modulation of the α5-nAChR/DNA methyltransferase 1 (DNMT1)/FHIT axis. In a chronic unpredictable stress (CUMS) mouse model, chronic stress promotes tumour development, accompanied by changes in α5-nAChR, DNMT1, FHIT, and vimentin. Together, these findings reveal a novel chronic stress-mediated LUAD signalling pathway: chronic stress enforces lung adenocarcinoma cell invasion and migration via the ACh/α5-nAChR/FHIT axis, which could be a potential therapeutic target for chronic stress-related LUAD.

Expression, correlation, and prognostic significance of different nicotinic acetylcholine receptors, programed death ligand 1, and dopamine receptor D2 in lung adenocarcinoma

Objective

The objective of this study is to evaluate the expression of different nicotinic acetylcholine receptors (nAChRs), programmed death ligand-1 (PD-L1), and dopamine receptor D2 (DRD2) as prognostic factors in lung cancer and any correlation among them. Since all of the above genes are typically upregulated in response to smoking, we hypothesized that a correlation might exist between DRD2, PD-L1, and nAChR expression in NSCLC patients with a smoking history and a prediction model may be developed to assess the clinical outcome.

Methods

We retrospectively analyzed samples from 46 patients with primary lung adenocarcinoma who underwent surgical resection at Mayo Clinic Rochester from June 2000 to October 2008. The expression of PD-L1, DRD2, CHRNA5, CHRNA7, and CHRNA9 were analyzed by quantitative PCR and correlated amongst themselves and with age, stage and grade, smoking status, overall survival (OS), and relapse-free survival (RFS).

Results

Only PD-L1 showed a statistically significant increase in expression in patients older than 65. All the above genes showed higher expression in stage IIIB than IIIA, but none reached statistical significance. Interestingly, we did not observe significant differences among never, former, and current smokers, but patients with pack years greater than 30 showed significantly higher expression of CHRNA9. We observed a strong positive correlation between PD-L1/DRD2, PD-L1/CHRNA5, and CHRNA5/CHRNA7 and a weak positive correlation between DRD2/CHRNA5 and DRD2/CHRNA7. Older age was independently associated with poor OS, whereas lower CHRNA7 expression was independently associated with better OS.

Conclusions

We observed strong positive correlations among PD-L1, DRD2, and some of the nAChRs. We investigated their prognostic significance in lung cancer patients and found CHRNA7 to be an independent prognostic factor. Overall, the results obtained from this preliminary study warrant a large cohort-based analysis that may ultimately lead to potential patient-specific stratification biomarkers predicting cancer-treatment outcomes.

Alpha5 nicotinic acetylcholine receptor mediated immune escape of lung adenocarcinoma via STAT3/Jab1-PD-L1 signalling

Background

Immunotherapy has proven to be an emerging treatment for non-small-cell lung cancer in recent years. Notably, smokers show higher programmed cell death ligand-1 (PD-L1) expression and better responses to PD-1/PD-L1 inhibitors than nonsmokers. Genome-wide association studies show that the CHRNΑ5 encoding α5-nicotinic acetylcholine receptor (α5-nAChR) is especially relevant to lung cancer and nicotine dependence. Jab1 is a key regulatory factor and promotes the stabilization of PD-L1. Our previous study reported that α5-nAChR mediates lung adenocarcinoma (LUAD) epithelial-mesenchymal transition (EMT) and metastasis via STAT3/Jab1. However, the link between α5-nAChR and PD-L1 is unclear in LUAD.

Methods

We used various bioinformatics databases to analyze the expression of related genes and their correlations. Expression and clinicopathologic significance of α5-nAChR and PD-L1 were detected by immunohistochemistry in a tissue microarray. α5-nAChR regulated LUAD cell immune escape by targeting the STAT3/Jab1-PD-L1 signalling by Western-blotting and ChIP in vitro. We used T cell coculture, flow cytometry, ELISA, CCK8 assay and crystal violet staining to detect the expression of regulatory T cell (Tregs), IFN-γ, IL-2 and the ability of T cell-mediated tumour cell killing respectively. IF assays were performed in both cancer cells and tumour xenograft paraffin sections to analyze the protein expression. The in vivo experiments in mouse model were performed to show the α5-nAChR-mediated immune escape via PD-L1 pathway.

Results

The expression of α5-nAChR was correlated with PD-L1 expression, smoking status and lower survival of LUAD in vivo. In vitro, the expression of α5-nAChR mediated phosphorylated STAT3 (pSTAT3), Jab1 and PD-L1 expression. STAT3 bound to the Jab1 or PD-L1 promoter and mediated PD-L1 expression. Jab1 stabilized PD-L1 expression in LUAD cells. Furthermore, in primary T cell cocultured system, downregulation of α5-nAChR suppressed the function of CD4⁺CD25⁺FOXP3⁺ Tregs, enhanced IFN-γ secretion, and increased T cell-mediated killing of LUAD cells. In the Jurkat T cells and LUAD cells coculture assay, inhibition of α5-nAChR increased IL-2 secretion. In tumour xenograft tissues, α5-nAChR expression was related to PD-L1, Jab1, pSTAT3, CD4 and granzyme B expression (GB).

Conclusions

Our results suggest that the novel α5-nAChR/STAT3-Jab1-PD-L1 axis is involved in LUAD immune escape, which could lead to potential therapeutic strategies for cancer immunotherapy.

Molecular mechanism, regulation, and therapeutic targeting of the STAT3 signaling pathway in esophageal cancer (Review)

Esophageal cancer (EC) is the seventh most common cancer globally, and the overall 5-year survival rate is only 20%. Signal transducer and activator of transcription 3 (STAT3) is aberrantly activated in EC, and its activation is associated with a poor prognosis. STAT3 can be activated by canonical pathways such as the JAK/STAT3 pathway as well as non-canonical pathways including the Wnt/STAT3 and COX2/PGE2/STAT3 pathways. Activated STAT3, present as phosphorylated STAT3 (p-STAT3), can be transported into the nucleus to regulate downstream genes, including VEGF, cyclin D1, Bcl-xL, and matrix metalloproteinases (MMPs), to promote cancer cell proliferation and induce resistance to therapy. Non-coding RNAs, including microRNAs (miRNAs/miRs), circular RNAs (circRNAs), and long non-coding RNAs (lncRNAs), play a vital role in regulating the STAT3 signaling pathway in EC. Several miRNAs promote or suppress the function of STAT3 in EC, while lncRNAs and circRNAs primarily promote the effects of STAT3 and the progression of cancer. Additionally, various drugs and natural compounds can target STAT3 to suppress the malignant behavior of EC cells, providing novel insights into potential EC therapies.

The α5-nAChR/PD-L1 axis facilitates lung adenocarcinoma cell migration and invasion

α5 nicotinic acetylcholine receptor (α5-nAChR) is associated with the progression of smoking-related lung adenocarcinoma (LUAD), but the molecular mechanism is unclear. Programmed death ligand 1 (PD-L1) is encoded by the CD274 gene, which not only inhibits the immune system, but also plays a unique role in tumor growth and metastasis. Here, we gained important insights into the underlying mechanism between α5-nAChR and PD-L1 in LUAD progression. α5-nAChR was overexpressed in various histological subtypes, cancer stages and metastasis statuses of LUAD. The group that coexpressed α5-nAChR and PD-L1 had a worse prognosis than the other subgroups at different stages of LUAD lymph node metastasis. The expression of α5-nAChR and PD-L1 was associated with epithelial-mesenchymal transition (EMT) marker CDH2. In vitro, α5-nAChR mediated nicotine-induced PD-L1 expression via STAT3 and the expression of EMT markers. Downregulation of α5-nAChR and/or PD-L1 inhibited EMT marker expression, cell proliferation, migration and invasion compared to silencing α5-nAChR or PD-L1 alone in LUAD cells. Furthermore, α5-nAChR expression was associated with PD-L1 and EMT marker expression in mouse xenograft models. These results highlight that α5-nAChR mediates STAT3/PD-L1 signaling, which contributes to cell migration and invasion. Therefore, our study may reveal a new interaction between α5-nAChR and PD-L1 that is involved in tumor cell growth and progression in LUAD, which may be a promising target for NSCLC diagnosis and immunotherapy.

Nicotine Activating α4β2 Nicotinic Acetylcholine Receptors to Suppress Neuroinflammation via JAK2-STAT3 Signaling Pathway in Ischemic Rats and Inflammatory Cells

Nicotine plays a role in inhibiting inflammatory factors, which contributes to improving cognitive impairment by activating α₄β₂ nAChRs in ischemic rats, but the underlying mechanism has not been fully elucidated. Janus tyrosine kinase 2-signal transducer and activator of transcription 3 (JAK2-STAT3) signaling pathway is involved in cognitive improvement, and there seems to be a relationship between nAChRs and JAK2-STAT3 as well. The aim of this study is to explore the role of JAK2-STAT3 signaling pathway in nicotine-mediated anti-inflammatory effect. Nicotine, DHβE (the strongest competitive antagonist of α₄β₂ nAChRs), and AG490 (a specific JAK2-STAT3 blocker) were used to intervene and treat ischemic rats and HEK-293 T-hα₄β₂ cells. The Morris water maze (MWM) test and 2-[¹⁸F]-A-85380 PET imaging were performed to detect the cognitive function and α₄β₂ nAChRs density in ischemic rats. The results demonstrated that nicotine intervention increased the density of α₄β₂ nAChRs and improved cognitive impairment, but this effect was blocked by AG490, and the receptors were still upregulated. Essentially, when the JAK2-STAT3 signaling pathway was blocked, nicotine could only upregulate the expression of α₄β₂ nAChRs, but not improve the cognitive function. PCR and Western blot analysis further confirmed these results. The cell experiments also showed that nicotine could reduce inflammatory factors stimulated by LPS and upregulate the expression of pJAK2 and pSTAT3 in HEK-293 T-hα₄β₂ cells, while AG490 and DHβE reversed the effect of nicotine. To sum up, our work indicated that JAK2-STAT3 signaling pathway played an important role in nicotine-induced cognitive improvement by upregulating α₄β₂ nAChRs in ischemic rats.

α5-nAChR associated with Ly6E modulates cell migration via TGF-β1/Smad signaling in non-small cell lung cancer

The α5-nicotinic acetylcholine receptor (α5-nAChR) is closely associated with nicotine-related lung cancer, offering a novel perspective for investigating the molecular pathogenesis of this disease. However, the mechanism by which α5-nAChR functions in lung carcinogenesis remains to be elucidated. Lymphocyte antigen 6 (Ly6) proteins, like snake three-finger alpha toxins such as α-bungarotoxin, can modulate nAChR signaling. Ly6E, a member of the Ly6 family, is a biomarker of poor prognosis in smoking-induced lung carcinogenesis and is involved in the regulation of TGF-β1/Smad signaling. Here, we explored the underlying mechanisms linking α5-nAChR and Ly6E in non-small cell lung cancer (NSCLC). The expression of α5-nAChR was correlated with Ly6 expression, smoking status and lower survival in NSCLC tissues. In vitro, α5-nAChR mediated Ly6E, the phosphorylation of the TGF-β1 downstream molecule Smad3 (pSmad3, a key mediator of TGF-β1 signaling), the epithelial-mesenchymal transition (EMT) markers Zeb1, N-cadherin and vimentin expression in NSCLC cells. The downregulation of Ly6E reduced α5-nAChR, pSmad3, Zeb1, N-cadherin and vimentin expression. Functionally, silencing both α5-nAChR and Ly6E significantly inhibited cell migration compared to silencing α5-nAChR or Ly6E alone. Furthermore, the functional effects of α5-nAchR and Ly6E were confirmed in chicken embryo chorioallantoic membrane (CAM) and mouse xenograft models. Therefore, our findings uncover a new interaction between α5-nAChR and Ly6E that inhibits cancer cell migration by modulating the TGF-β1/Smad signaling pathway in NSCLC, which may serve as a novel target for therapeutic intervention.

Nicotinic Acetylcholine Receptors in the Respiratory Tract

Nicotinic acetylcholine receptors (nAChR) are widely distributed in neuronal and non-neuronal tissues, where they play diverse physiological roles. In this review, we highlight the recent findings regarding the role of nAChR in the respiratory tract with a special focus on the involvement of nAChR in the regulation of multiple processes in health and disease. We discuss the role of nAChR in mucociliary clearance, inflammation, and infection and in airway diseases such as asthma, chronic obstructive pulmonary disease, and cancer. The subtype diversity of nAChR enables differential regulation, making them a suitable pharmaceutical target in many diseases. The stimulation of the α3β4 nAChR could be beneficial in diseases accompanied by impaired mucociliary clearance, and the anti-inflammatory effect due to an α7 nAChR stimulation could alleviate symptoms in diseases with chronic inflammation such as chronic obstructive pulmonary disease and asthma, while the inhibition of the α5 nAChR could potentially be applied in non-small cell lung cancer treatment. However, while clinical studies targeting nAChR in the airways are still lacking, we suggest that more detailed research into this topic and possible pharmaceutical applications could represent a valuable tool to alleviate the symptoms of diverse airway diseases.

Targeting ion channels for the treatment of lung cancer

Lung cancer is caused by several environmental and genetic variables and is globally associated with elevated morbidity and mortality. Among these variables, membrane-bound ion channels have a key role in regulating multiple signaling pathways in tumor cells and dysregulation of ion channel expression and function is closely related to proliferation, migration, and metastasis of lung cancer. This work reviews and summarizes current knowledge about the role of ion channels in lung cancer, focusing on the changes in the expression and function of various ion channels in lung cancer and how these changes affect lung cancer cell biology both in vitro and in vivo as evidenced by both genetic and pharmacological studies. It can help understand the molecular mechanisms of various ion channels influencing the initiation and progression of lung cancer and shed new insights into their roles in the development and treatment of this deadly disease.

E-cigarette vape and lung ACE2 expression: Implications for coronavirus vulnerability

Evidence in humans suggests a correlation between nicotine smoking and severe respiratory symptoms with COVID-19 infection. In lung tissue, angiotensin-converting enzyme 2 (ACE2) appears to mechanistically underlie viral entry. Here, we investigated whether e-cigarette vapor inhalation alters ACE2 and nicotinic acetylcholine receptor (nAChR) expression in male and female mice. In male lung, nicotine vapor inhalation induced a significant increase in ACE2 mRNA and protein, but surprisingly, these differences were not found in females. Further, both vehicle and nicotine vapor inhalation downregulated α5 nAChR subunits in both sexes, while differences were not found in α7 nAChR subunit expression. Finally, blood ACE2 levels did not differ with exposure, indicating that blood sampling is not a sufficient indicator of lung ACE2 changes. Together, these data indicate a direct link between e-cigarette vaping and increased ACE2 expression in male lung tissue, which thereby reveals an underlying mechanism of increased vulnerability to coronavirus infection in individuals vaping nicotine.

α-Conotoxins and α-Cobratoxin Promote, while Lipoxygenase and Cyclooxygenase Inhibitors Suppress the Proliferation of Glioma C6 Cells

Among the brain tumors, glioma is the most common. In general, different biochemical mechanisms, involving nicotinic acetylcholine receptors (nAChRs) and the arachidonic acid cascade are involved in oncogenesis. Although the engagement of the latter in survival and proliferation of rat C6 glioma has been shown, there are practically no data about the presence and the role of nAChRs in C6 cells. In this work we studied the effects of nAChR antagonists, marine snail α-conotoxins and snake α-cobratoxin, on the survival and proliferation of C6 glioma cells. The effects of the lipoxygenase and cyclooxygenase inhibitors either alone or together with α-conotoxins and α-cobratoxin were studied in parallel. It was found that α-conotoxins and α-cobratoxin promoted the proliferation of C6 glioma cells, while nicotine had practically no effect at concentrations below 1 µL/mL. Nordihydroguaiaretic acid, a nonspecific lipoxygenase inhibitor, and baicalein, a 12-lipoxygenase inhibitor, exerted antiproliferative and cytotoxic effects on C6 cells. nAChR inhibitors weaken this effect after 24 h cultivation but produced no effects at longer times. Quantitative real-time polymerase chain reaction showed that mRNA for α4, α7, β2 and β4 subunits of nAChR were expressed in C6 glioma cells. This is the first indication for involvement of nAChRs in mechanisms of glioma cell proliferation.

Identification of CHRNB4 as a Diagnostic/Prognostic Indicator and Therapeutic Target in Human Esophageal Squamous Cell Carcinoma

Esophageal squamous cell carcinoma (ESCC) is one of the most aggressive malignant tumors and there is a lack of biomarkers for ESCC diagnosis and prognosis. Family subunits of cholinergic nicotinic receptor genes (CHRNs) are involved in smoking behavior and tumor cell proliferation. Previous researches have shown similar molecular features and pathogenic mechanisms among ESCC, head and neck squamous cell carcinoma (HNSC), and lung squamous cell carcinoma (LUSC). Using edgeR, three mutual differentially expressed genes of CHRNs were found to be significantly upregulated at the mRNA level in ESCC, LUSC, and HNSC compared to matched normal tissues. Kaplan–Meier survival analysis showed that high expression of CHRNB4 was associated with unfavorable prognosis in ESCC and HNSC. The specific expression analysis revealed that CHRNB4 is highly expressed selectively in squamous cell carcinomas compared to adenocarcinoma. Cox proportional hazards regression analysis was performed to find that just the single gene CHRNB4 has enough independent prognostic ability, with the area under curve surpassing the tumor-node-metastasis (TNM) staging-based model, the most commonly used model in clinical application in ESCC. In addition, an effective prognostic nomogram was established combining the TNM stage, gender of patients, and expression of CHRNB4 for ESCC patients, revealing an excellent prognostic ability when compared to the model of CHRNB4 alone or TNM. Gene Set Enrichment Analysis results suggested that the expression of CHRNB4 was associated with cancer-related pathways, such as the mTOR pathway. Cell Counting Kit-8, cloning formation assay, and western blot proved that CHRNB4 knockdown can inhibit the proliferation of ESCC cells via the Akt/mTOR and ERK1/2/mTOR pathways, which might facilitate the prolonged survival of patients. Furthermore, we conducted structure-based molecular docking, and potential modulators against CHRNB4 were screened from FDA approved drugs. These findings suggested that CHRNB4 specifically expressed in SCCs, and may serve as a promising biomarker for diagnosis and prognosis prediction, and it can even become a therapeutic target of ESCC patients.

α5-nAChR and survivin: Two potential biological targets in lung adenocarcinoma

Recent studies have shown that the overexpression of α5 nicotinic acetylcholine receptor (α5-nAChR) is associated with nicotine-related lung carcinogenesis. Survivin is one of the biomarkers of a worse prognosis for smoking-related lung cancer. The aim of this study is to investigate the association of α5-nAChR, survivin, and clinical outcomes in lung adenocarcinoma (LUAD). We analyzed the expression level and correlation of CHRNA5 (encoding α5-nAChR) and BIRC5 (encoding survivin) in LUAD with The Cancer Genome Atlas data set. The relationship between overall survival (OS) and the expression of CHRNA5 or/and BIRC5 was evaluated by the Kaplan-Meier method and Cox proportional hazards model. Moreover, our results showed that the expression of α5-nAChR mediated survivin expression in lung cancer cells and in lung tumor xenografts. Relationships between the expression of α5-nAChR and/or survivin with clinical-pathological characteristics were analyzed using LUAD tissue samples. The results showed that expression of α5-nAChR was correlated with survivin expression in vitro and in vivo. The group coexpressing α5-nAChR and survivin had a worse prognosis than other subgroups in LUAD (p < .05). In conclusion, ascertaining the expression of both α5-nAChR and survivin provides a better measure of prognosis for LUAD patients. The combined inhibition of α5-nAChR and survivin may be a promising multitargeted gene therapeutic strategy in LUAD diagnosis.

α5-nAChR contributes to epithelial-mesenchymal transition and metastasis by regulating Jab1/Csn5 signalling in lung cancer

Recent studies have showed that α5 nicotinic acetylcholine receptor (α5‐nAChR) is closely associated with nicotine‐related lung cancer. Our previous studies also demonstrated that α5‐nAChR mediates nicotine‐induced lung carcinogenesis. However, the mechanism by which α5‐nAChR functions in lung carcinogenesis remains to be elucidated. Jab1/Csn5 is a key regulatory factor in smoking‐induced lung cancer. In this study, we explored the underlying mechanisms linking the α5‐nAChR‐Jab1/Csn5 axis with lung cancer epithelial‐mesenchymal transition (EMT) and metastasis, which may provide potential therapeutic targets for future lung cancer treatments. Our results demonstrated that the expression of α5‐nAChR was correlated with the expression of Jab1/Csn5 in lung cancer tissues and lung cancer cells. α5‐nAChR expression is associated with Jab1/Csn5 expression in lung tumour xenografts in mice. In vitro, the expression of α5‐nAChR mediated Stat3 and Jab1/Csn5 expression, significantly regulating the expression of the EMT markers, N‐cadherin and Vimentin. In addition, the down‐regulation of α5‐nAChR or/and Stat3 reduced Jab1/Csn5 expression, while the silencing of α5‐nAChR or Jab1/Csn5 inhibited the migration and invasion of NSCLC cells. Mechanistically, α5‐nAChR contributes to EMT and metastasis by regulating Stat3‐Jab1/Csn5 signalling in NSCLC, suggesting that α5‐nAChR may be a potential target in NSCLC diagnosis and immunotherapy.

Nicotine Upregulates the Level of Mcl-1 through STAT3 in H1299 Cells

Background: Nicotine contributes to development of human lung cancer and chemoresistance through activation of myeloid cell leukemia-1 (Mcl-1). Signal transducer and activator of transcription 3 (STAT3) generally participates in development and progression of human cancers. Therefore, we examined the STAT3 cascade in nicotine regulation of Mcl-1 transcription in human lung cancer cells.

Methods: The effects of nicotine on the expression of STAT3 and Mcl-1 were determined using western blot. The sub-cellular localization was tested using immunofluorescence. The activity of STAT3 promoter was checked using dual luciferase reporter assay.

Results: STAT3 was constitutively activated (i.e., tyrosine-phosphorylated, serine-phosphorylated and nuclear translocation), meanwhile the expression and transcriptional activity of Mcl-1 were up-regulated in lung cancer cells following treatment with nicotine. Transfection with siRNA targeting STAT3 or treatment with STAT3 inhibitor JSI-124 diminished Mcl-1 protein levels. Deleted mutagenesis of a putative STAT3 consensus binding sequence decreased Mcl-1 promoter activity and eliminated the increase of Mcl-1 promoter activity induced by nicotine. Abnormally, JAK (Jannus kinase) inhibitor AG490 can't induce the downregulation of Mcl-1 or inhibit the tyrosine-phosphorylation of STAT3. In addition, deactivated mutagenesis of STAT3 the tyrosine 705 site had no effect on the aggregation of STAT3 into nucleus induced by nicotine.

Conclusions: We have demonstrated that nicotine induces up-regulation of Mcl-1 through STAT3, which process may be independent on JAKs and not only dependent on the phosphorylation of Y705. Downregulation of Mcl-1 transcription by inhibiting STAT3 cascade may be a potential strategy for the treatment of this cancer.

Ion Channels in Lung Cancer

Ion channels are a major class of membrane proteins that play central roles in signaling within and among cells, as well as in the coupling of extracellular events with cellular responses. Dysregulated ion channel activity plays a causative role in many diseases including cancer. Here, we will review their role in lung cancer. Lung cancer is one of the most frequently diagnosed cancers, and it causes the highest number of deaths of all cancer types. The overall 5-year survival rate of lung cancer patients is only 19% and decreases to 5% when patients are diagnosed with stage IV. Thus, new therapeutical strategies are urgently needed. The important contribution of ion channels to the progression of various types of cancer has been firmly established so that ion channel-based therapeutic concepts are currently developed. Thus far, the knowledge on ion channel function in lung cancer is still relatively limited. However, the published studies clearly show the impact of ion channel inhibitors on a number of cellular mechanisms underlying lung cancer cell aggressiveness such as proliferation, migration, invasion, cell cycle progression, or adhesion. Additionally, in vivo experiments reveal that ion channel inhibitors diminish tumor growth in mice. Furthermore, some studies give evidence that ion channel inhibitors can have an influence on the resistance or sensitivity of lung cancer cells to common chemotherapeutics such as paclitaxel or cisplatin.

Association Between Nicotine-dependent Gene Polymorphism and Smoking Cessation in Patients With Lung Cancer

BACKGROUND

Patients with lung cancer continue to smoke owing to complex factors. Failure to quit smoking (defined as nicotine dependence) is significantly associated with genetic status. This study aimed to investigate the relationship between polymorphisms in nicotine dependence genes and smoking status after the diagnosis of lung cancer.

PATIENTS AND METHODS

A total of 240 patients with lung cancer were included from July 2017 to March 2018. According to the actual smoking condition after lung cancer diagnosis, eligible patients were divided into 3 groups: the never-smoking group, the failure to quit smoking group, and the successful smoking cessation group. Fagerstrom Test for Nicotine Dependence scores were used to evaluate the smoking status of each group. Three nicotine-dependent genes with 6 loci were detected.

RESULTS

Among the 240 patients, 86 were never-smokers, 51 failed to quit smoking, and 104 successfully quit smoking. The initial age of smoking in the failure to quit smoking group was significantly younger than those in the successful smoking cessation group (P = .001). There was a significant difference in the GG and AG and AA genotype distributions of CHRNA3 (rs578776) among the 3 groups (P = .003). There was also a significant difference in the distribution of CHRNA4 (rs2229959) genotypes among the 3 groups (P = .003). However, there was no significant difference in the genotype distribution of CHRNA5 (rs588765) among the 3 groups (P = .277).

CONCLUSIONS

Gene polymorphisms of CHRNA3 (rs578776) and CHRNA4 (rs1044396 and rs2229959) were associated with the success of smoking cessation after the diagnosis of lung cancer, which should be considered in the management of smoking cessation after patients are diagnosed with lung cancer.

Cholinergic Receptor Nicotinic Alpha 5 (CHRNA5) RNAi is associated with cell cycle inhibition, apoptosis, DNA damage response and drug sensitivity in breast cancer

Cholinergic Receptor Nicotinic Alpha 5 (CHRNA5) is an important susceptibility locus for nicotine addiction and lung cancer. Depletion of CHRNA5 has been associated with reduced cell viability, increased apoptosis and alterations in cellular motility in different cancers yet not in breast cancer. Herein we first showed the expression of CHRNA5 was variable and positively correlated with the fraction of total genomic alterations in breast cancer cell lines and tumors indicating its potential role in DNA damage response (DDR). Next, we demonstrated that silencing of CHRNA5 expression in MCF7 breast cancer cell line by RNAi affected expression of genes involved in cytoskeleton, TP53 signaling, DNA synthesis and repair, cell cycle, and apoptosis. The transcription profile of CHRNA5 depleted MCF7 cells showed a significant positive correlation with that of A549 lung cancer cell line while exhibiting a negative association with the CHRNA5 co-expression profile obtained from Cancer Cell Line Encylopedia (CCLE). Moreover, it exhibited high similarities with published MCF7 expression profiles obtained from exposure to TP53 inducer nutlin-3a and topoisomerase inhibitors. We then demonstrated that CHRNA5 siRNA treatment reduced cell viability and DNA synthesis indicating G1 arrest while it significantly increased apoptotic sub-G1 cell population. Accordingly, we observed lower levels of phosphorylated RB (Ser807/811) and an increased BAX/BCL2 ratio in RNAi treated MCF7 cells. We also showed that CHRNA5 RNAi transcriptome correlated negatively with DDR relevant gene expression profile in breast cancer gene expression datasets while the coexposure to topoisomerase inhibitors in the presence of CHRNA5 RNAi enhanced chemosensitivity potentially due to reduced DDR. CHRNA5 RNAi consistently lowered total CHEK1 mRNA and protein levels as well as phosphorylated CHEK1 (Ser345) in MCF7 cells. We also detected a significant positive correlation between the expression levels of CHRNA5 and CHEK1 in CCLE, TCGA and METABRIC breast cancer datasets. Our study suggests CHRNA5 RNAi is associated with cell cycle inhibition, apoptosis as well as reduced DDR and increased drug sensitivity in breast cancer yet future studies are warranted since dose- and cell line-specific differences exist in response to CHRNA5 depletion. Gene expression microarray data can be accessed from GEO database under the accession number GSE89333.

Acetylcholine signaling system in progression of lung cancers

The neurotransmitter acetylcholine (ACh) acts as an autocrine growth factor for human lung cancer. Several lines of evidence show that lung cancer cells express all of the proteins required for the uptake of choline (choline transporter 1, choline transporter-like proteins) synthesis of ACh (choline acetyltransferase, carnitine acetyltransferase), transport of ACh (vesicular acetylcholine transport, OCTs, OCTNs) and degradation of ACh (acetylcholinesterase, butyrylcholinesterase). The released ACh binds back to nicotinic (nAChRs) and muscarinic receptors on lung cancer cells to accelerate their proliferation, migration and invasion. Out of all components of the cholinergic pathway, the nAChR-signaling has been studied the most intensely. The reason for this trend is due to genome-wide data studies showing that nicotinic receptor subtypes are involved in lung cancer risk, the relationship between cigarette smoke and lung cancer risk as well as the rising popularity of electronic cigarettes considered by many as a "safe" alternative to smoking. There are a small number of articles which review the contribution of the other cholinergic proteins in the pathophysiology of lung cancer. The primary objective of this review article is to discuss the function of the acetylcholine-signaling proteins in the progression of lung cancer. The investigation of the role of cholinergic network in lung cancer will pave the way to novel molecular targets and drugs in this lethal malignancy.

Identification of COL1A1 as an invasion‑related gene in malignant astrocytoma

Malignant astrocytoma (MA) is the most common and severe type of brain tumor. A greater understanding of the underlying mechanisms responsible for the development of MA would be beneficial for the development of targeted molecular therapies. In the present study, the upregulated differentially expressed genes (DEGs) in MA were obtained from the Gene Expression Omnibus database using R/Bioconductor software. DEGs in different World Health Organization classifications were compared using the Venny tool and 15 genes, including collagen type I α1 chain (COL1A1) and laminin subunit γ1 (LAMC1), were revealed to be involved in the malignant progression of MA. In addition, the upregulated DEGs in MA were evaluated using functional annotations of Gene Ontology and Kyoto Encyclopedia of Genes and Genomes with the Database for Annotation, Visualization, and Integrated Discovery tool. The results indicated that invasion-associated enrichment was observed in 'extracellular matrix' (ECM), 'cell adhesion' and 'phosphoinositide 3-kinase-protein kinase B signaling pathway'. Subsequently, the analysis of the protein-protein interactions was performed using STRING and Cytoscape software, which revealed that the ECM component was the invasion-associated module and its corresponding genes included COL1A1, LAMC1 and fibronectin 1. Finally, survival Kaplan-Meier estimate was conducted using cBioportal online, which demonstrated that COL1A1 expression affected the survival of and recurrence in patients with MA. Moreover, the results of in vitro Transwell assay and western blot analysis revealed that the depleted levels of COL1A1 also decreased the expression of several proteins associated with cell invasion, including phosphorylated-signal transducer and activator of transcription 3, matrix metalloproteinase (MMP)-2, MMP-9 and nuclear factor-κB. On the whole, the present study identified the invasion-related target genes and the associated potential pathways in MA. The results indicated that COL1A1 may be a candidate biomarker for the prognosis and treatment of MA.

Nicotine Induces Progressive Properties of Lung Adenocarcinoma A549 Cells by Inhibiting Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Expression and Plasma Membrane Localization

Lung cancer remains one of the most common cancer-related deaths worldwide. The cigarette smoking is a risk factor for lung cancer development. Interestingly, the cystic fibrosis transmembrane conductance regulator encoded by CFTR gene, an ATP-binding cassette transporter-class ion channel that conducts chloride and bicarbonate anions across membrane of epithelial cells, has recently been suggested to play a role in the development and progression of many types of cancer. It has been well-documented that mutations of CFTR gene are the cause of cystic fibrosis, the most common fatal hereditary lung disease in Caucasian population; the function of cystic fibrosis transmembrane conductance regulator in the development of lung cancer however has not yet been established. In the present study, we aimed to interrogate the impact of cystic fibrosis transmembrane conductance regulator on the nicotine-promoted progressive potency in lung adenocarcinoma cells by assessing capacities of cystic fibrosis transmembrane conductance regulator to cell migration, invasion, and clonogenicity and the expression of markers of cell proliferation and lung stem cell-related transcription factors in lung adenocarcinoma A549 cells. The exposure of nicotine exhibited an ability to enhance progressive properties of adenocarcinoma cells including A549 cells, HCC827 cells, and PC-9 cells, alone with an inhibition of cystic fibrosis transmembrane conductance regulator protein expression. Remarkably, an overexpression of cystic fibrosis transmembrane conductance regulator significantly inhibited the progressive potency of A549 cells, including capacity of cell migration and invasion and clonogenicity, along with a decreased expression of cell proliferative markers Ki67, p63, and proliferating cell nuclear antigen, and cancer stem cell marker CD133, stem cell pluripotency-related transcription factors octamer-binding transcription factor ¾, and sex-determining region Y-box 2, regardless of the presence of nicotine. In contrast, opposite effects were observed in A549 cells that the cystic fibrosis transmembrane conductance regulator was knockdown by short hairpin RNA to cystic fibrosis transmembrane conductance regulator. This study thus suggests that cystic fibrosis transmembrane conductance regulator may play a tumor suppressor role in lung cancer cells, which may be a novel therapeutic target warranted for further investigation.