Thioredoxin facilitates hepatocellular carcinoma stemness and metastasis by increasing BACH1 stability to activate the AKT/mTOR pathway.

Thioredoxin (TXN) is essential for preserving balance and controlling the intracellular redox state. Most studies have focused on the function of TXN in redox reactions, which is critical for tumor progression. Here, we showed that TXN promotes hepatocellular carcinoma (HCC) stemness properties in a non-redox-dependent manner, which has rarely been reported in previous studies. TXN exhibited upregulated expression in human HCC specimens, which was associated with a poor prognosis. Functional studies showed that TXN promoted HCC stemness properties and facilitated HCC metastasis both in vitro and in vivo. Mechanistically, TXN promoted the stemness of HCC cells by interacting with BTB and CNC homology 1 (BACH1) and stabilized BACH1 expression by inhibiting its ubiquitination. BACH1 was positively correlated with TXN expression and was significantly upregulated in HCC. In addition, BACH1 promotes HCC stemness by activating the AKT/mammalian target of rapamycin (mTOR) pathway. Furthermore, we found that the specific inhibition of TXN in combination with lenvatinib in mice significantly improved the treatment of metastatic HCC. In summary, our data demonstrate that TXN plays a crucial role in HCC stemness and BACH1 plays an integral part in regulating this process by activating the AKT/mTOR pathway. Thus, TXN is a promising target for metastatic HCC therapy.

Screening of Organic Small Molecule Excipients on Ternary Solid Dispersions Based on Miscibility and Hydrogen Bonding Analysis: Experiments and Molecular Simulation.

The preparation of solid dispersions by mixing insoluble drugs with polymers is the main way to improve the aqueous solubility of drugs. The introduction of organic small molecule excipients into binary solid dispersions is expected to further enhance drug solubility by regulating intermolecular hydrogen bonding within the system at the microscopic level. In this study, we used carbamazepine (CBZ) as the target drug and polyvinylpyrrolidone as the solid dispersion matrix and screened the third component from 13 organic small molecules with good miscibility in the solid dispersion based on the principle of similarity of solubility parameters. The hydrogen bonding parameters and dissociation Gibbs free energy of the 13 organic small molecule-CBZ dimer were calculated by quantum mechanical simulation, and the tryptophan (Try) was identified as the optimal third component of organic small molecule. The migration of CBZ in binary and ternary systems was also analyzed by molecular dynamics simulation. On this theoretical basis, the corresponding solid dispersions were prepared, characterized, and tested for solubility analysis, which verified that the drug solubility was stronger for the system with the addition of polar fractions and the Try was indeed the best third component of organic small molecule compound, which was consistent with the simulation predictions. This screening method may provide theoretical guidance for drug modification design and clinical studies.

Chemoenzymatic Synthesis of Cylindrocyclophanes A and F and Merocyclophanes A and D.

Incorporating enzymatic reactions into natural product synthesis can significantly improve synthetic efficiency and selectivity. In contrast to the increasing applications of biocatalytic functional-group interconversions, the use of enzymatic C-C bond formation reactions in natural product synthesis is underexplored. Herein, we report a concise and efficient approach for the synthesis of [7.7]paracyclophane natural products, a family of polyketides with diverse biological activities. By using enzymatic Friedel-Crafts alkylation, cylindrocyclophanes A and F and merocyclophanes A and D were synthesized in six to eight steps in the longest linear sequence. This study demonstrates the power of combining enzymatic reactions with contemporary synthetic methodologies and provides opportunities for the structure-activity relationship studies of [7.7]paracyclophane natural products.

Single-cell transcriptomic analysis reveals key immune cell phenotypes in the lungs of patients with asthma exacerbation.

BACKGROUND: Asthma exacerbations are associated with heightened asthma symptoms, which can result in hospitalization in severe cases. However, the molecular immunologic processes that determine the course of an exacerbation remain poorly understood, impeding the progression of development of effective therapies. OBJECTIVE: Our aim was to identify candidate genes that are strongly associated with asthma exacerbation at a cellular level. METHODS: Subjects with asthma exacerbation and healthy control subjects were recruited, and bronchoalveolar lavage fluid was isolated from these subjects via bronchoscopy. Cells were isolated through fluorescence-activated cell sorting, and single-cell RNA sequencing was performed on enriched cell populations. RESULTS: We showed that the levels of monocytes, CD8+ T cells, and macrophages are significantly elevated in the bronchoalveolar lavage fluid of patients. A set of cytokines and intracellular transduction regulators are associated with asthma exacerbations and are shared across multiple cell clusters, forming a complicated molecular framework. An additional group of core exacerbation-associated modules is activated, including eukaryotic initiation factor 2 signaling, ephrin receptor signaling, and C-X-C chemokine receptor type 4 signaling in the subpopulations of CD8+ T cells (C1-a) and monocyte clusters (C7 clusters), which are associated with infection. CONCLUSION: Our study identified a significant number of severe asthma-associated genes that are differentially expressed by multiple cell clusters.

Increased Drought Resistance 1 Mutation Increases Drought Tolerance of Upland Rice by Altering Physiological and Morphological Traits and Limiting ROS Levels.

To discover new mutants conferring enhanced tolerance to drought stress, we screened a mutagenized upland rice (Oryza sativa) population (cv. IAPAR9) and identified a mutant, named idr1-1 (increased drought resistance 1-1), with obviously increased drought tolerance under upland field conditions. The idr1-1 mutant possessed a significantly enhanced ability to tolerate high-drought stresses. Map-based cloning revealed that the gene LOC_Os05g26890, residing in the mapping region of IDR1 locus, carried a single-base deletion in the idr1-1 mutant. IDR1 encodes the Gα subunit of the heterotrimeric G protein (also known as RGA1), and this protein was localized in nucleus and to plasma membrane or cell periphery. Further investigations indicated that the significantly increased drought tolerance in idr1-1 mutants stemmed from a range of physiological and morphological changes, including greater leaf potentials, increased proline contents, heightened leaf thickness and upregulation of antioxidant-synthesizing and drought-induced genes, under drought-stressed conditions. Especially, reactive oxygen species (ROS) production might be remarkably impaired, while ROS-scavenging ability appeared to be markedly enhanced due to significantly elevated expression of ROS-scavenging enzyme genes in idr1-1 mutants under drought-stressed conditions. In addition, idr1-1 mutants showed reduced expression of OsBRD1. Altogether, these results suggest that mutation of IDR1 leads to alterations in multiple layers of regulations, which ultimately leads to changes in the physiological and morphological traits and limiting of ROS levels, and thereby confers obviously increased drought tolerance to the idr1-1 mutant.

CircTUBGCP3 facilitates the tumorigenesis of lung adenocarcinoma by sponging miR-885-3p.

BACKGROUND: Circular RNAs (circRNAs) act pivotal roles in the progression of multiple malignancies. However, the underlying mechanisms by which hsa_circ_0007031 (circTUBGCP3) contributes to lung adenocarcinoma (LAC) remain largely unknown. METHODS: The association of circTUBGCP3 expression with clinicopathological characteristics and prognosis in patients with LAC was determined by RT-qPCR and fluorescence in situ hybridization. The in vitro functional experiments as well as a subcutaneous tumorigenesis model were executed to estimate the role of circTUBGCP3 in LAC cells. The interaction between circTUBGCP3 and miR-885-3p was confirmed by RNA immunoprecipitation, luciferase gene report and RT-qPCR assays. The effects of circTUBGCP3 on miR-885-3p-mediated Wnt10b/ß-catenin signaling were evaluated by Western blot. RESULTS: The upregulation of circTUBGCP3 or downregulation of miR-885-3p was associated with the pathological stage and poor survival in patients with LAC. Restored expression of circTUBGCP3 facilitated the growth and invasion of LAC cells, but knockdown of circTUBGCP3 harbored the opposite effects. In mechanism, circTUBGCP3 could act as a sponge of miR-885-3p, which suppressed the cell proliferation and colony formation and attenuated the tumor-promoting effects of circTUBGCP3. Wnt10b as a target of miR-885-3p could be upregulated be circTUBGCP3 and indicate poor survival in patient with LAC. CONCLUSIONS: Our findings demonstrated that circTUBGCP3 promoted LAC progression by sponging miR-885-3p, and might represent a prognostic factor for LAC.

CircTIMELESS regulates the proliferation and invasion of lung squamous cell carcinoma cells via the miR-136-5p/ROCK1 axis.

Numerous studies demonstrate that circular RNAs (circRNAs) are critical regulators of the occurrence and progression of tumors. However, research on the involvement of circRNAs in lung squamous cell carcinoma (LUSC) is limited. In our study, circTIMELESS (also named hsa_circ_0000408 in the Human circRNA Database) was upregulated in both LUSC tissues and LUSC cells, and circTIMELESS expression was positively associated with the TNM stage. Moreover, circTIMELESS silencing markedly suppressed invasion in vitro and disrupted proliferation in vitro as well as in vivo. Additional investigations have shown that circTIMELESS functions as a miR-136-5p "sponge" and regulates miR-136-5p expression. Furthermore, the impact of miR-136-5p upregulation was consistent with the results of circTIMELESS silencing, both of which inhibited the proliferation and invasion of LUSC cells. Additional results showed that Rho-associated coiled-coil containing protein kinase 1 (ROCK1) is targeted by miR-136-5p. The results of recovery experiments showed that ROCK1 overexpression partly rescued the impact of circTIMELESS silencing and miR-136-5p upregulation on proliferation and invasion. Consequently, our findings confirmed that circTIMELESS exists in LUSC and acts as a tumor promoter through the miR-136-5p/ROCK1 axis. Based on these findings, circTIMELESS may be potentially utilized as a therapeutic target for LUSC.

miR-363-3p inhibits migration, invasion, and epithelial-mesenchymal transition by targeting NEDD9 and SOX4 in non-small-cell lung cancer.

miR-363-3p is downregulated in lung adenocarcinoma and can inhibit tumor growth. Here, we aimed to investigate the effect of miR-363-3p on non-small-cell lung cancer (NSCLC) metastasis. In our study, miR-363-3p overexpression inhibited cell migration and invasion via epithelial-mesenchymal transition inhibition, while miR-363-3p knockdown exhibited the opposite effects. Further studies demonstrated that miR-363-3p bound to 3'-untranslated regions of NEDD9 and SOX4, and negatively regulated their levels. Interestingly, NEDD9 or SOX4 knockdown rescued the metastasis-promoting effects of antagomiR-363-3p. The inhibitory effects of agomiR-363-3p were also blocked by NEDD9 or SOX4 overexpression. Moreover, lentivirus particles carrying pre-miR-363 (LV-pre-miR-363) significantly decreased, while LV-miR-363-3p inhibitor increased metastatic nodule numbers and the levels of NEDD9 and SOX4 in lungs. In conclusion, tumor suppressor miR-363-3p may be a potential target in NSCLC therapy.

LncRNA NR2F2-AS1 promotes tumourigenesis through modulating BMI1 expression by targeting miR-320b in non-small cell lung cancer.

Recently, long noncoding RNAs (lncRNAs) are attracting wide attention in the field of cancer research because of its important role in cancer diagnosis and prognosis. But studies on the biological effects and relevant mechanisms of lncRNAs in non-small cell lung cancer (NSCLC) remain few and need to be enriched. Our study discussed the expression and biological effects of LncRNA NR2F2-AS1, and further explored its possible molecular mechanisms. As a result, elevated expression of NR2F2-AS1 was detected in NSCLC tissues and cells and was remarkably associated with the tumor, node, metastasis (TNM) stage and the status of lymphatic metastasis of patients. Down-regulated NR2F2-AS1 contributed to the promotion of cell apoptosis and the inhibition of cell proliferation and invasion in A549 and SPC-A-1 cells in vivo and vitro. Through bioinformatics analysis, NR2F2-AS1 functions as a ceRNA directly binding to miR-320b, BMI1 was a direct target of miR-320b. Combined with the following cellular experiments, the data showed that NR2F2-AS1 may influence the NSCLC cell proliferation, invasion and apoptosis through regulating miR-320b targeting BMI1.

Baicalein inhibits cell growth and increases cisplatin sensitivity of A549 and H460 cells via miR-424-3p and targeting PTEN/PI3K/Akt pathway.

Lung cancer is the leading cause of death in individuals with malignant disease. Non-small-cell lung cancer (NSCLC) is the most common type of lung cancer, and chemotherapy drugs such as cisplatin are the most widely used treatment for this disease. Baicalein is a purified flavonoid compound that has been reported to inhibit cancer cell growth and metastasis and increase sensitization to chemotherapeutic drugs via different pathways. Therefore, we assessed the effects of baicalein on the proliferation, apoptosis and cisplatin sensitivity in the NSCLC A549 and H460 cell lines and determined the pathways through which baicalein exerts its effects. Baicalein was slightly toxic to normal human bronchial NHBE cells but inhibited growth, induced apoptosis and increased cisplatin sensitivity in A549 and H460 cells. Baicalein down-regulated miR-424-3p, up-regulated PTEN expression and down-regulated expression of PI3K and p-Akt in A549 and H460 cells. Dual-luciferase reporter assay demonstrated that PTEN is a target gene of miR-424-3p, and overexpression of miR-424-3p or silencing of PTEN partially attenuated the effects of baicalein on A549 and H460 cells. Taken together, we concluded that baicalein inhibits cell growth and increases cisplatin sensitivity to A549 and H460 cells via down-regulation of miR-424-3p and targeting the PTEN/PI3K/Akt pathway.

Aberrant expression of hsa_circ_0025036 in lung adenocarcinoma and its potential roles in regulating cell proliferation and apoptosis.

As the most common histological subtype of lung cancer, lung adenocarcinoma remains a tremendous risk to public health, which requires ceaseless efforts to elucidate the potential diagnostic and therapeutic strategies. Circular RNAs (circRNAs) have been identified with emerging roles in tumorigenesis and development. Our preliminary work noticed that hsa_circ_0025036 was significantly upregulated in lung adenocarcinoma tissues. However, its specific roles in lung adenocarcinoma remain unclear. The results in this study revealed that hsa_circ_0025036 existed as a circular form and was aberrantly upregulated in lung adenocarcinoma tissues via quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Its expression level exhibited a close link with aggressive clinicopathological parameters including cancer differentiation, TNM stage and lymph node metastasis. hsa_circ_0025036 knockdown significantly suppressed cell proliferation and promoted cell apoptosis in A549 and Calu-3 cells. Moreover, hsa_circ_0025036/miR-198/SHMT1&TGF-α axis was identified via bioinformatics analysis and Dual-Luciferase Reporter assays. miR-198 inhibitors reversed the function of hsa_circ_0025036 knockdown. hsa_circ_0025036 knockdown exerted similar effects with miR-198 upregulation on cell proliferation and apoptosis. In conclusion, we demonstrate that hsa_circ_0025036 regulates cell proliferation and apoptosis in lung adenocarcinoma cells probably via hsa_circ_0025036/miR-198/SHMT1&TGF-α axis. hsa_circ_0025036 may serve as a potential prognostic biomarker and a therapeutic target for lung adenocarcinoma.

Long Non-Coding RNA XLOC_008466 Functions as an Oncogene in Human Non-Small Cell Lung Cancer by Targeting miR-874.

BACKGROUND: The therapy and prognosis of lung cancer are difficult because of multiple genetic and epigenetic alterations. Long non-coding RNAs (lncRNAs) have been verified as new mediators of cancer development and progression by virtue of their various functions. Here, we focused on the lncRNA XLOC_008466 based on previous microarray data. However, whether aberrant expression of XLOC_008466 in human non-small cell lung cancer (NSCLC) is correlated with malignancy, metastasis or prognosis has not been elucidated. METHODS: We performed real-time PCR, CCK-8, flow cytometry, trans-well, western blotting, luciferase reporter assays, RNA immunoprecipitation (RIP) assay and surface plasmon resonance (SPR) assay to detect the function of XLOC_008466 in NSCLC. RESULTS: Up-regulation of XLOC_008466 in NSCLC patients was related to lymph node metastasis and the TNM stage. In vitro, down-regulation of XLOC_008466 inhibited cell proliferation and invasion of A549 and H460 cells in vitro, but promoted cell apoptosis. Experiments on mechanisms revealed that XLOC_008466 functioned as a ceRNA, directly binding to miR-874, and could affect cell proliferation, apoptosis and invasion through regulation of miR-874 expression as well as by increasing matrix metalloproteinase 2 (MMP2) and X-linked inhibitor of apoptosis (XIAP) expression. CONCLUSIONS: XLOC_008466 functions as an oncogene in NSCLC by regulating the miR-874-MMP2/XIAP axis, which indicates that XLOC_008466 may be a useful marker and potential therapeutic target in NSCLC.

Impact of COPD and emphysema on survival of patients with lung cancer: A meta-analysis of observational studies.

Both COPD and emphysema are associated with an increased incidence of lung cancer, but the impacts of these comorbidities on lung cancer prognosis are still unclear. Herein, we conducted a meta-analysis to clarify whether the presence of these comorbidities indicates poor survival in patients with lung cancer. A comprehensive search was conducted using PubMed, Embase, Web of Science, ASCO Abstracts and Cochrane library for articles published before 1 June 2015. Papers referenced by the obtained articles were also reviewed. Main outcomes were overall survival (OS) and disease-free survival (DFS) in patients with lung cancer. Pooled hazard ratio (HR) and 95% confidence intervals (CIs) were calculated using random-effects models. Subgroup and sensitivity analyses were also conducted. Of 58 full texts reviewed, 26 met our inclusion criteria that were derived from 21 and seven studies examining the impacts of COPD and emphysema on survival of lung cancer, respectively. Meta-analyses revealed that concomitant COPD was associated with poorer OS (HR, 1.17; 95% CI: 1.10-1.25, n = 20), which was independent of tumour staging, diagnostic criteria of COPD or location, and DFS (HR, 1.52; 95% CI: 1.04-2.23, n = 6) with high heterogeneity (I(2) = 78%). The presence of emphysema in patients with lung cancer predicted worse OS (HR, 1.66; 95% CI: 1.25-2.22, n = 7), but not poorer DFS. The presence of COPD and emphysema are robust predictors of poor survival in patients with lung cancer. Early detection of these diseases should be taken into account for lung cancer surveillance and management.

MiR-144 inhibits proliferation and induces apoptosis and autophagy in lung cancer cells by targeting TIGAR.

BACKGROUND: MiRNAs are noncoding RNAs of 20-24 nucleotides that function as post-transcriptional negative regulators of gene expression. MiRNA genes are usually transcribed by RNA polymerase II in the nucleus. Their initial products are pre-miRNAs which have cap sequences and polyA tails. The p53-induced glycolysis and apoptosis regulator (TIGAR) was discovered through microarray analysis of gene expression following activation of p53. However, little is known about the effect of miR-144 on cell proliferation and apoptosis and how it interacts with TIGAR. METHODS: We performed real-time PCR, western blotting, CCK8, colony formation, tumor growth, flow cytometry, Caspase3/7 activity, Hoechst 33342 staining, MDC staining of autophagic cells and luciferase reporter assays to detect the influence of miR-144 to lung cancer cells. RESULTS: miR-144 targeted TIGAR, inhibited proliferation, enhanced apoptosis, and increased autophagy in A549 and H460 cells. CONCLUSIONS: Our study improves our understanding of the mechanisms underlying lung cancer pathogenesis and may promote the development of novel targeted therapies.

Downregulation of microRNA-182 inhibits cell growth and invasion by targeting programmed cell death 4 in human lung adenocarcinoma cells.

Lung cancer is a major cause of cancer death worldwide. Programmed cell death 4 (PDCD4), an important tumor suppressor, influences transcription and translation of multiple genes and modulates different signal transduction pathways. However, the upstream regulation of this gene is largely unknown. In our study, we found that microRNA-182 (miR-182) was upregulated, whereas PDCD4 was downregulated in lung cancer cell lines. We performed methyl thiazolyl tetrazolium and colony formation assays to study the influence of miR-182 on proliferation of the lung cancer cell lines A549 and SPC-A-1. We also carried out Transwell and wound healing assays to investigate the effect of miR-182 on invasion and migration of A549 and SPC-A-1. Finally, using the luciferase reporter assay and restore assay, we demonstrated that PDCD4 is a direct target of miR-182. These results suggest that in lung adenocarcinoma cells, miR-182 plays an oncogenic role as a direct negative regulator of PDCD4.

Up-regulation of microRNA-138 induce radiosensitization in lung cancer cells.

Deregulation of microRNAs (miRNAs) is implicated in tumor progression. We attempt to identify the association between miR-138 and Sentrin/SUMO-specific protease 1 (SENP1) as a radiosensitization-related gene and characterize the biological function by which SENP1 was regulated by miR-138 to influence radiosensitization in lung cancer cells. In this study, we showed that miRNA-138 is reduced in both lung cancer clinical specimens and cell lines and is effective to inhibit SENP1 expression. Moreover, high levels of miR-138 are associated with lower levels of lung cancer cell proliferation and colony formation. Then, we investigated the underlying mechanisms responsible for the increase in the radiosensitivity of lung cancer cells when SENP1 is inhibited by miR-138. We further show that the increased radiosensitivity may be the result of an increased γ-H2AX expression, an increased rate of apoptosis, and changes in the cell cycle. In conclusion, our data demonstrate that the miR-138/SENP1 cascade is relative to radiosensitization in lung cancer cells and is a potential radiotherapy target.

MiR-495 regulates proliferation and migration in NSCLC by targeting MTA3.

Our previous studies have showed that metastasis-associated protein 3 (MTA 3) is overexpressed in non-small cell lung cancer (NSCLC) tissue, and increased MTA3 mRNA levels is a risk factor of lymph node metastasis. Using bioinformatics analyses, we found that MTA3 was a potential target of miR-495. However, the pathophysiological role of miR-495 and its relevance to the growth and development of NSCLC have yet to be investigated. The purpose of this study was to elucidate the molecular mechanisms by which miR-495 acts as a tumor suppressor in NSCLC. qRT-PCR data showed significant downregulation of miR-495 in 56 NSCLC tissue samples and 5 lung cancer cell lines, compared with their adjacent normal tissue; furthermore, western blotting analysis revealed MTA3 protein was overexpressed in the tumor samples compared with the matched adjacent normal tissue. MiR-495 was shown to not only inhibit the proliferation of lung cancer cells (A549 and Calu-3) but also to inhibit cell migration in vitro. Using western blotting and luciferase assays, MTA3 was identified as a target of miR-495. These findings suggest the importance of miR-495 targeting of MTA3 in the regulation of lung cancer growth and migration.

Linking ecophysiological modelling with quantitative genetics to support marker-assisted crop design for improved yields of rice (Oryza sativa) under drought stress.

BACKGROUND AND AIMS: Genetic markers can be used in combination with ecophysiological crop models to predict the performance of genotypes. Crop models can estimate the contribution of individual markers to crop performance in given environments. The objectives of this study were to explore the use of crop models to design markers and virtual ideotypes for improving yields of rice (Oryza sativa) under drought stress. METHODS: Using the model GECROS, crop yield was dissected into seven easily measured parameters. Loci for these parameters were identified for a rice population of 94 introgression lines (ILs) derived from two parents differing in drought tolerance. Marker-based values of ILs for each of these parameters were estimated from additive allele effects of the loci, and were fed to the model in order to simulate yields of the ILs grown under well-watered and drought conditions and in order to design virtual ideotypes for those conditions. KEY RESULTS: To account for genotypic yield differences, it was necessary to parameterize the model for differences in an additional trait 'total crop nitrogen uptake' (Nmax) among the ILs. Genetic variation in Nmax had the most significant effect on yield; five other parameters also significantly influenced yield, but seed weight and leaf photosynthesis did not. Using the marker-based parameter values, GECROS also simulated yield variation among 251 recombinant inbred lines of the same parents. The model-based dissection approach detected more markers than the analysis using only yield per se. Model-based sensitivity analysis ranked all markers for their importance in determining yield differences among the ILs. Virtual ideotypes based on markers identified by modelling had 10-36 % more yield than those based on markers for yield per se. CONCLUSIONS: This study outlines a genotype-to-phenotype approach that exploits the potential value of marker-based crop modelling in developing new plant types with high yields. The approach can provide more markers for selection programmes for specific environments whilst also allowing for prioritization. Crop modelling is thus a powerful tool for marker design for improved rice yields and for ideotyping under contrasting conditions.

Symbiotic microbial communities in various locations of the lung cancer respiratory tract along with potential host immunological processes affected.

Lung cancer has the highest mortality rate among all cancers worldwide. The 5-year overall survival rate for non-small cell lung cancer (NSCLC) is estimated at around 26%, whereas for small cell lung cancer (SCLC), the survival rate is only approximately 7%. This disease places a significant financial and psychological burden on individuals worldwide. The symbiotic microbiota in the human body has been significantly associated with the occurrence, progression, and prognosis of various diseases, such as asthma, chronic obstructive pulmonary disease (COPD), and cystic fibrosis. Studies have demonstrated that respiratory symbiotic microorganisms and their metabolites play a crucial role in modulating immune function and contributing to the pathophysiology of lung cancer through their interactions with the host. In this review, we provide a comprehensive overview of the microbial characteristics associated with lung cancer, with a focus on the respiratory tract microbiota from different locations, including saliva, sputum, bronchoalveolar lavage fluid (BALF), bronchial brush samples, and tissue. We describe the respiratory tract microbiota's biodiversity characteristics by anatomical region, elucidating distinct pathological features, staging, metastasis, host chromosomal mutations, immune therapies, and the differentiated symbiotic microbiota under the influence of environmental factors. Our exploration investigates the intrinsic mechanisms linking the microbiota and its host. Furthermore, we have also provided a comprehensive review of the immune mechanisms by which microbiota are implicated in the development of lung cancer. Dysbiosis of the respiratory microbiota can promote or inhibit tumor progression through various mechanisms, including DNA damage and genomic instability, activation and regulation of the innate and adaptive immune systems, and stimulation of epithelial cells leading to the upregulation of carcinogenesis-related pathways.