Nicotinic acetylcholine receptors in cancer: Limitations and prospects

Perspectives on the α5 nicotinic acetylcholine receptor in lung cancer progression

Nicotinic acetylcholine receptors (nAChRs) are widely expressed in a variety of cell types and are involved in multiple physiological regulatory mechanisms in cells, tissues and systems. Increasing evidence suggests that the α5 nicotinic acetylcholine receptor (α5-nAChR), encoded by the CHRNA5 gene, is one of a key mediator involved in lung cancer development and immune responses. Several studies have shown that it is a regulator that stimulates processes via various signaling pathways, including STAT3 in lung cancer. In addition, α5-nAChR has a profound effect on lung immune response through multiple immune-related factor pathways. In this review, we focus on the perspectives on α5-nAChR in lung cancer progression, which indicates that targeting α5-nAChR could provide novel anticancer and immune therapy strategies for lung cancer.

α5-nAChR/NETO2 contributed to chronic stress-promoted lung adenocarcinoma progression

BACKGROUND

α5-nicotinic acetylcholine receptor (α5-nAChR) participates in chronic stress-promoted lung adenocarcinoma (LUAD) progression. Neuropilin and tolloid-like 2 (NETO2) contributes to fear expression and extinction, which is related to tumorigenesis. CHRNA5 (encoding α5-nAChR) gene profiling revealed a reduction in NETO2 expression following CHRNA5 knockdown. Nevertheless, the connection between α5-nAChR and NETO2 in LUAD progression induced by chronic stress remains unclear.

METHODS

RNA-Seq and bioinformatics database were used for analyzing the expression as well as correlation of α5-nAChR, together with NETO2 in LUAD. α5-nAChR and NETO2 expression were detected using immunohistochemistry in LUAD tissue microarrays, chronic restraint stress (CRS) and chronic unpredictable stress (CUMS) mice tissues. In lung adenocarcinoma A549 and H1299 cells, the expression of α5-nAChR, NETO2, p-CAMKII, p-STAT3 and vimentin induced by acetylcholine/nicotine was examined by western blot. The interaction of α5-nAChR with NETO2 in lung adenocarcinoma cells was detected by Co-immunoprecipitation assay and modeled using molecular docking. EdU assay and colony formation assay were conducted to evaluate cell proliferation, while wound healing assay as well as transwell assay assessed the migration and invasion of lung adenocarcinoma cells.

RESULTS

α5-nAChR expression was related to NETO2 expression, low survival rate, staging as well as smoking status in LUAD dataset as well as tissue microarrays. The correlation between α5-nAChR and NETO2 was validated in nude mice xenograft tissues. α5-nAChR as well as NETO2 expression correlated in CRS and CUMS mice tissues. In vitro, acetylcholine/nicotine mediated NETO2, p-CAMKII, p-STAT3 and vimentin expression via α5-nAChR. α5-nAChR interacted with NETO2 as well as CAMKII in LUAD cells. α5-nAChR/NETO2 signaling contributed to LUAD cell proliferation, migration and invasion.

CONCLUSIONS

The above results uncover a new chronic stress-promoted LUAD signaling pathway: α5-nAChR/NETO2 axis contributes to chronic stress-promoted LUAD cell proliferation, migration and invasion.

WGCNA and integrative network analysis identify CHRNA5 and CTLA4 as potential therapeutic targets against angiosarcoma

Angiosarcomas are a type of soft-tissue sarcoma characterized by aggressive malignant tumors originating from endothelial cells of blood vessels or lymphatic vessels. Limited studies have been done to explore the molecular pathophysiology of the disease, with rather limited studies involving transcriptomic analyzes. This study was undertaken to identify the shared molecular signatures and gene modules associated with angiosarcomas of various origin. Transcriptomic data analysis of publicly available data was done followed by WGCNA to identify shared signature gene modules. The Maximal Clique Centrality algorithm was applied to gene modules, and unclustered network analysis was conducted on differentially expressed genes to identify true hub genes. The expression of candidate genes in various cancer types was analyzed using GEPIA. WGCNA analysis identified five significant modules, with the most enriched module being associated with angiogenesis and cell junction regulators. The intersection of true hub genes from MCC analysis of WGCNA modules and high-degree nodes from an unclustered network revealed eight consistently overexpressed genes in all angiosarcoma samples.Among the eight enriched genes, CHRNA5 and CTLA4, are exclusively overexpressed in angiosarcoma and not in other cancers of the same tissue origin, with significant drug-protein interactions suggesting their potential as therapeutic targets.

The Distinct Biological Effects of 6-Hydroxy-L-Nicotine in Representative Cancer Cell Lines

6-hydroxy-L-nicotine (6HLN) is a nicotine (NIC) derivative with proven therapeutic potential in neurodegenerative disorders. Here, the impact of 6HLN on cell growth, migratory behavior, and inflammatory status of three different cancer cell lines (A549, MCF7, and U87) and two normal cell lines (16HBE14o and MCF10A) was investigated. In silico analyses were conducted to evaluate the binding affinity of 6HLN to nicotinic receptors (nAChRs) containing α9 and α5 subunits. The obtained in silico data revealed that 6HLN might act on the cholinergic system. Interestingly, the in vitro data showed the compound has cancer-stimulatory effects in U87 glioblastoma cells and cancer-inhibitory effects in MCF7 breast cancer cells. In A549 lung cancer cells, no changes were detected upon 6HLN administration. More importantly, 6HLN appears not to be deleterious for normal cells, with the viability of 16HBE14o pulmonary cells and MCF10A mammary cells remaining unchanged.

Neuroscience in peripheral cancers: tumors hijacking nerves and neuroimmune crosstalk

Cancer neuroscience is an emerging field that investigates the intricate relationship between the nervous system and cancer, gaining increasing recognition for its importance. The central nervous system governs the development of the nervous system and directly affects brain tumors, and the peripheral nervous system (PNS) shapes the tumor microenvironment (TME) of peripheral tumors. Both systems are crucial in cancer initiation and progression, with recent studies revealing a more intricate role of the PNS within the TME. Tumors not only invade nerves but also persuade them through remodeling to further promote malignancy, creating a bidirectional interaction between nerves and cancers. Notably, immune cells also contribute to this communication, forming a triangular relationship that influences protumor inflammation and the effectiveness of immunotherapy. This review delves into the intricate mechanisms connecting the PNS and tumors, focusing on how various immune cell types influence nerve‒tumor interactions, emphasizing the clinical relevance of nerve‒tumor and nerve‒immune dynamics. By deepening our understanding of the interplay between nerves, cancer, and immune cells, this review has the potential to reshape tumor biology insights, inspire innovative therapies, and improve clinical outcomes for cancer patients.

α4 Nicotinic Acetylcholine Receptors in Lipopolysaccharide-Related Lung Inflammation

Sepsis remains an important healthcare challenge. The lungs are often affected in sepsis, resulting in acute lung injury characterized by inflammation. Mechanisms involving lipopolysaccharide (LPS) stimulation of toll-like receptor (TLR) signaling with induction of proinflammatory pathways have been implicated in this process. To date, however, studies targeting these pathways have failed to improve outcomes. We have found that LPS may also promote lung injury through the activation of α4 nicotinic acetylcholine receptors (α4 nAChRs) in immune cells. We observed increased expression of α4 nAChRs in human THP-1 monocytic cells exposed to LPS (100 ng/mL, 24 h). We also observed that LPS stimulated the expression of other relevant genes, including tumor necrosis factor-α, interleukin-1β, plasminogen activator inhibitor-1, the solute carrier family 7 member 11, extracellular superoxide dismutase, and transforming growth factor-β1. Of interest, dihydro-β-erythroidine hydrobromide (DHβE), a specific chemical inhibitor of α4 nAChRs, inhibited the LPS-induced expression of these genes. We generated mice with a global knockout mutation of the α4 nAChR subunit in the C57BL/6 background using CRISPR/Cas9 technology. The lungs of these LPS-treated animals demonstrated a reduction in the expression of the above-mentioned genes when compared with the lungs of wild-type animals. In support of the role of oxidative stress, we observed that LPS induced expression of the cystine transporter Slc7a11 in both THP-1 cells and in wild-type mouse lungs. The effects of LPS on THP-1 cells were blocked by the thiol antioxidant N-acetylcysteine and mimicked by redox stress. Importantly, the induction of IL-1β by redox stress was inhibited by the α4 nAChR inhibitor DHβE. Finally, we showed that LPS stimulated calcium influx in THP-1 cells, which was blocked by the α4 nAChR inhibitor. Our observations suggest that LPS promotes lung injury by stimulating redox stress, which activates α4 nAChR signaling and drives proinflammatory cytokine expression.

Nicotinic Acetylcholine Receptors in Glial Cells as Molecular Target for Parkinson's Disease

Parkinson's disease (PD) is a progressive neurodegenerative disease characterized by resting tremor, bradykinesia, rigidity, and postural instability that also includes non-motor symptoms such as mood dysregulation. Dopamine (DA) is the primary neurotransmitter involved in this disease, but cholinergic imbalance has also been implicated. Current intervention in PD is focused on replenishing central DA, which provides remarkable temporary symptomatic relief but does not address neuronal loss and the progression of the disease. It has been well established that neuronal nicotinic cholinergic receptors (nAChRs) can regulate DA release and that nicotine itself may have neuroprotective effects. Recent studies identified nAChRs in nonneuronal cell types, including glial cells, where they may regulate inflammatory responses. Given the crucial role of neuroinflammation in dopaminergic degeneration and the involvement of microglia and astrocytes in this response, glial nAChRs may provide a novel therapeutic target in the prevention and/or treatment of PD. In this review, following a brief discussion of PD, we focus on the role of glial cells and, specifically, their nAChRs in PD pathology and/or treatment.

The role of α7 nicotinic acetylcholine receptors in post-acute sequelae of covid-19

Post-Acute Sequelae of COVID-19 or Long COVID becomes evident some weeks to months following acute COVID-19. Symptoms include cognitive impairment and varying degrees of memory loss with no definitive etiologies or efficacious therapies forthcoming even after four years of the SARS-Cov2 pandemic virus. The aim of this review is to demonstrate the important role of α7 nicotinic acetylcholine receptors in both acute COVID-19 and Long COVID. Evidence presented implicates immune mechanisms stimulated by SARS-Cov-2 S-protein fragment 674-685 that possesses homology with α7-specific ligands. Cognitive dysfunctions observed in Long COVID patients may be derived from anti-idiotypic α7-specific antibodies stimulated by (674-685)-specific antibodies. Therapeutic interventions capable of neutralizing these antibodies and restoring full functions of α7 nicotinic acetylcholine receptors appear to be of paramount importance in post-acute sequelae of COVID-19.

Evidence based on Mendelian randomization: Causal relationship between mitochondrial biological function and lung cancer and its subtypes

OBJECTIVE

This study aimed to investigate the causal relationship between mitochondrial biological function and lung cancer, including its subtypes, via MR.

METHODS

SNPs significantly associated with lung cancer and its subtypes were employed as instrumental variables. MR-Egger regression, simple mode, weighted mode, simple median, and weighted median, were utilized to determine the causal relationship between the exposure factor and the occurrence of lung cancer and its subtypes.

RESULTS

NADH dehydrogenase (ubiquinone) flavoprotein 2 and transmembrane protein 70 were found to have a causal relationship with lung adenocarcinoma, acting as protective factors. The causal relationship between mitochondrial import inner membrane translocase subunit and NADH dehydrogenase (ubiquinone) iron-sulfur protein 4 and small-cell lung cancer was established as a risk factor. NADH dehydrogenase (ubiquinone) 1 beta subcomplex subunit 8 exhibited a causal relationship with small-cell lung cancer, acting as a protective factor. Furthermore, NAD-dependent protein deacylase sirtuin-5 was causally linked to lung squamous cell carcinoma, serving as a protective factor. A funnel plot demonstrated the symmetrical distribution of the SNPs. Thew pleiotroy test (P > 0.05) and "leave-one-out" test validated the relative stability of the results.

CONCLUSION

This study established a causal relationship between mitochondrial biological function and lung cancer, including its subtypes.