Lymph node micrometastasis in non-small cell lung cancer

TNNT1 accelerates migration, invasion and EMT progression in lung cancer cells

BACKGROUND

Clinically, most patients with lung cancer (LC) die from tumor spread and metastasis. Specific metastasis-related molecules can provide reference for clinical prediction of efficacy, evaluation of prognosis, and search for the best treatment plan. Troponin T1 (TNNT1) is highly expressed in various cancer tissues, which affects malignant behavior of tumor cells and is related to patients' survival and prognosis. However, the role and molecular mechanism of TNNT1 in LC invasion and metastasis have not yet been investigated.

METHODS

Gene expression profiling interactive analysis (GEPIA) online analysis was used to analyze TNNT1 expression in LC tissues. Quantitative real-time-polymerase chain reaction (qRT-PCR) or western blot were performed to measure TNNT1 or epithelial-to-mesenchymal transition (EMT)-related and Wnt/β-catenin pathway-related protein expression in LC cells. After TNNT1 knockdown, cell scratch healing and transwell assays were introduced to assess cell migration and invasion, respectively.

RESULTS

TNNT1 expression in LC tissues and cells was increased. TNNT1 knockdown notably impaired LC cell migration, invasion and EMT. TNNT1 knockdown inhibited Wnt/β-catenin pathway of LC cells. Lithium chloride (LiCl) addition partially restored the inhibition of TNNT1 knockdown on migration, invasion, EMT and Wnt/β-catenin of LC cells.

CONCLUSION

TNNT1 knockdown attenuated LC migration, invasion and EMT, possibly through Wnt/β-catenin signaling.

A case report of loss of thyroid transcription factor 1 expression in lung adenocarcinoma EBUS FNA

We present a case report of a 76-year-old male with a histologically confirmed KRAS mutated, thyroid transcription factor 1 (TTF1) positive, grade 1, mucinous adenocarcinoma with cytologically difficult to interpret lymph node metastasis showing loss of TTF1 expression and overlapping features with goblet cell hyperplasia. The case highlights the importance of molecular testing in aiding diagnosis and guiding treatment of non-small cell lung carcinomas (NSCLC).

Regulatory mechanism and expression level of PRPS2 in lung cancer

BACKGROUND

Lung cancer, with high morbidity and mortality, is the commonest respiratory system neoplasm, which seriously endangers the life safety of patients. In this study, the effect of PRPS2 on cell progression was preliminarily investigated.

METHODS

Immunohistochemical staining, western blot and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) were performed to verify the expression level of PRPS2 in lung cancer. Lung cancer cell lines with stable downregulation of PRPS2 were constructed in A549 cells and NCIH460 cells. The function of PRPS2 silencing on the proliferation ability was verified by the EdU and cell colony formation experiment. Scratch and transwell tests were conducted to verify the role of PRPS2 silencing on the migratory and invasive ability of cells. The impact of PRPS2 silencing on cell apoptosis and cell cycle was verified by flow cytometry test. The effects of PRPS2 silencing on apoptosis-associated proteins were assessed by western blot assay. The function of PRPS2 silencing on tumor growth in vivo was studied through xenograft tumor experiment.

RESULTS

In comparison with normal tissues, PRPS2 was upregulated in lung cancer tissues. PRPS2 knockdown notably hindered the migratory ability, invasive ability and proliferation, but accelerated cell apoptosis. In vivo experiments confirmed that PRPS2 silencing blocked the growth of transplanted tumors.

CONCLUSION

In lung cancer, PRPS2 silencing suppressed the malignant progression, indicating that PRPS2 might be a novel biomarker for lung cancer treatment and diagnosis.

Novel genome-wide DNA methylation profiling reveals distinct epigenetic landscape, prognostic model and cellular composition of early-stage lung adenocarcinoma

BACKGROUND

Lung adenocarcinoma (LUAD) has been a leading cause of cancer-related mortality worldwide. Early intervention can significantly improve prognosis. DNA methylation could occur in the early stage of tumor. Comprehensive understanding the epigenetic landscape of early-stage LUAD is crucial in understanding tumorigenesis.

METHODS

Enzymatic methyl sequencing (EM-seq) was performed on 23 tumors and paired normal tissue to reveal distinct epigenetic landscape, for compared with The Cancer Genome Atlas (TCGA) 450K methylation microarray data. Then, an integrative analysis was performed combined with TCGA LUAD RNA-seq data to identify significant differential methylated and expressed genes. Subsequently, the prognostic risk model was constructed and cellular composition was analyzed.

RESULTS

Methylome analysis of EM-seq comparing tumor and normal tissues identified 25 million cytosine-phosphate-guanine (CpG) sites and 30,187 differentially methylated regions (DMR) with a greater number of untraditional types. EM-seq identified a significantly higher number of CpG sites and DMRs compared to the 450K microarray. By integrating the differentially methylated genes (DMGs) with LUAD-related differentially expressed genes (DEGs) from the TCGA database, we constructed prognostic model based on six differentially methylated-expressed genes (MEGs) and verified our prognostic model in GSE13213 and GSE42127 dataset. Finally, cell deconvolution based on the in-house EM-seq methylation profile was used to estimate cellular composition of early-stage LUAD.

CONCLUSIONS

This study firstly delves into novel pattern of epigenomic DNA methylation and provides a multidimensional analysis of the role of DNA methylation revealed by EM-seq in early-stage LUAD, providing distinctive insights into its potential epigenetic mechanisms.

IGSF10 inhibits the metastasis of lung adenocarcinoma via the Spi-B/Integrin-β1 signaling pathway

IGSF10, a protein that belongs to the immunoglobulin superfamily, is involved in regulating the early migration of neurons that produce gonadotropin-releasing hormone and performs a fundamental function in development. Our previous study confirmed that the mRNA expression level of IGSF10 may be a protective prognosis factor for lung adenocarcinoma (LUAD) patients. However, the specific mechanisms of IGSF10 are still unclear. In this research, it was shown that the protein level of IGSF10 was down-modulated in LUAD tissues and had a link to the clinical and pathological characteristics as well as the patient's prognosis in LUAD. Importantly, IGSF10 regulates the metastatic ability of LUAD cells in vitro and in vivo. It was proven in a mechanistic sense that IGSF10 inhibits the capacity of LUAD cells to metastasize through the Spi-B/Integrin-β1 signaling pathway. These findings gave credence to the premise that IGSF10 performed a crucial function in LUAD.

METTL3-mediated the m6A modification of SF3B4 facilitates the development of non-small cell lung cancer by enhancing LSM4 expression

BACKGROUND

Splicing factor B subunit 4 (SF3B4) has been confirmed to participate in the progression of many cancers and is considered to be a potential target for non-small cell lung cancer (NSCLC). Thus, the role and molecular mechanism of SF3B4 in NSCLC progression deserves further study.

METHODS

Quantitative real-time PCR and western blot were employed to detect the mRNA and protein levels of SF3B4, Sm-like protein 4 (LSM4) and methyltransferase-like 3 (METTL3). Cell proliferation, apoptosis, invasion, migration and stemness were tested by cell counting kit-8, colony formation, flow cytometry, transwell, wound healing, and sphere formation assays. The interaction between SF3B4 and METTL3 or LSM4 was confirmed by MeRIP, RIP and Co-IP assays. Mice xenograft models were constructed to assess the effects of METTL3 and SF3B4 on NSCLC tumorigenesis.

RESULTS

SF3B4 had high expression in NSCLC tissues and was associated with the shorter overall survival of NSCLC patients. Knockdown of SF3B4 suppressed NSCLC cell proliferation, invasion, migration and stemness, while inducing apoptosis. METTL3 promoted SF3B4 mRNA stability by m6A modification, and its knockdown inhibited NSCLC cell growth, metastasis and stemness by downregulating SF3B4. SF3B4 could interact with LSM4, and sh-SF3B4-mediated the inhibition on NSCLC cell functions could be reversed by LSM4 overexpression. In addition, reduced METTL3 expression restrained NSCLC tumor growth, and this effect was reversed by SF3B4 overexpression.

CONCLUSION

METTL3-stablized SF3B4 promoted NSCLC cell growth, metastasis and stemness via positively regulating LSM4.

Revolutionizing lymph node metastasis imaging: the role of drug delivery systems and future perspectives

The deployment of imaging examinations has evolved into a robust approach for the diagnosis of lymph node metastasis (LNM). The advancement of technology, coupled with the introduction of innovative imaging drugs, has led to the incorporation of an increasingly diverse array of imaging techniques into clinical practice. Nonetheless, conventional methods of administering imaging agents persist in presenting certain drawbacks and side effects. The employment of controlled drug delivery systems (DDSs) as a conduit for transporting imaging agents offers a promising solution to ameliorate these limitations intrinsic to metastatic lymph node (LN) imaging, thereby augmenting diagnostic precision. Within the scope of this review, we elucidate the historical context of LN imaging and encapsulate the frequently employed DDSs in conjunction with a variety of imaging techniques, specifically for metastatic LN imaging. Moreover, we engage in a discourse on the conceptualization and practical application of fusing diagnosis and treatment by employing DDSs. Finally, we venture into prospective applications of DDSs in the realm of LNM imaging and share our perspective on the potential trajectory of DDS development.

Prognostic significance of T lymphocyte subgroups (CD4 and CD8) in lung cancer patients after neoadjuvant chemotherapy

OBJECTIVE

The basis for current and future lung cancer immunotherapy depends on our knowledge of molecular mechanisms of interactions between tumor and immune system cells. Interactions that occur between different intratumoral populations of the same cells are important. In our study, we aimed to evaluate relationship between the clinical and prognostic features and T lymphocyte subgroups of patients with lung tumors after neoadjuvant treatment.

METHODS

A total of 72 patients were included in our study, including study group, 39 of whom received neoadjuvant chemotherapy. Clinical/radiological/pathological findings of patients and CD4/CD8 staining rates in peritumoral/intratumoral areas were recorded.

RESULTS

Our study revealed significantly lower intratumoral CD4 + T cell density and lower intratumoral CD4/CD8 ratio in primary tumor after neoadjuvant therapy (respectively, 0.012 and 0.016). Considering tumor types, when control-study groups were compared, inflammation was statistically significant only in adenocarcinoma subtype; intratumoral CD4/CD8 ratio was statistically significant only in squamous-cell carcinoma subtype (respectively, p = 0.0008 and p = 0.0139). When CD4 + T lymphocytes and CD8 + T lymphocytes and CD4/CD8 ratio were compared between control and study groups in low-stage patients according to clinical stages, only intratumoral CD4 + T lymphocyte values and intratumoral CD4/CD8 ratio were significant (respectively, p = 0.0291 ve p = 0.0154).

CONCLUSION

All cell types of innate and adaptive intratumoral immunity can affect lung cancer tissues simultaneously, and these interactions have a very complex structure. Understanding the tumor microenvironment and the different roles of associated cancer immune cells may lead to the discovery of new targets for immunological therapies and increased survival times in lung cancer.

METTL14 enhances the m6A modification level of lncRNA MSTRG.292666.16 to promote the progression of non-small cell lung cancer

BACKGROUND

m6A modification has close connection with the occurrence, development, and prognosis of tumors. This study aimed to explore the roles of m6A modification and its related mechanisms in non-small cell lung cancer (NSCLC).

METHODS

NSCLC tissues and their corresponding para-cancerous tissues were collected to determine the m6A levels of total RNA/lncRNAs and the expression of m6A modification-related genes/lncRNAs. Then, A549 cells were transfected with si-METTL14 or oe-METTL14, and the cell transfection efficiency was assessed. Subsequently, the viability, apoptosis, cell colony formation, migration and invasion of the different cells were determined. Finally, the nude mouse tumorigenicity experiments were performed to observe the effects of METTL14 in vivo.

RESULTS

Compared to the para-NSCLC tissues, the m6A level and METTL14 expression were both significantly increased in the NSCLC tissues (P < 0.05). Based on the expression of METTL14 in the different cell lines, A549 cells were chosen for further experiments. Then, the A549 cells with METTL14 knockdown and overexpression were successfully established, as well as it was found that METTL14 knockdown could inhibit the viability, colony formation, migration, and invasion of A549 cells, while facilitate their apoptosis. In vivo experiments also showed that METTL14 knockdown could inhibit tumor formation and growth. Additionally, the m6A level of MSTRG.292666.16 was higher in the NSCLC tissues; and after METTL14 knockdown, the expression and m6A level of MSTRG.292666.16 were both significantly reduced in A549 cells, and vice versa.

CONCLUSION

METTL14 may promote the progression of NSCLC through up-regulating MSTRG.292666.16 and enhance its m6A modification level.

Neoadjuvant therapy in non-small cell lung cancer: basis, promise, and challenges

Introduction

Survival rates for early-stage non-small cell lung cancer (NSCLC) remain poor despite the decade-long established standard of surgical resection and systemic adjuvant therapy. Realizing this, researchers are exploring novel therapeutic targets and deploying neoadjuvant therapies to predict and improve clinical and pathological outcomes in lung cancer patients. Neoadjuvant therapy is also increasingly being used to downstage disease to allow for resection with a curative intent. In this review, we aim to summarize the current and developing landscape of using neoadjuvant therapy in the management of NSCLC.

Methods

The PubMed.gov and the ClinicalTrials.gov databases were searched on 15 January 2023, to identify published research studies and trials relevant to this review. One hundred and seven published articles and seventeen ongoing clinical trials were selected, and relevant findings and information was reviewed.

Results & Discussion

Neoadjuvant therapy, proven through clinical trials and meta-analyses, exhibits safety and efficacy comparable to or sometimes surpassing adjuvant therapy. By attacking micro-metastases early and reducing tumor burden, it allows for effective downstaging of disease, allowing for curative surgical resection attempts. Research into neoadjuvant therapy has necessitated the development of surrogate endpoints such as major pathologic response (MPR) and pathologic complete response (pCR) allowing for shorter duration clinical trials. Novel chemotherapy, immunotherapy, and targeted therapy agents are being tested at a furious rate, paving the way for a future of personalized systemic therapy in NSCLC. However, challenges remain that prevent further mainstream adoption of preoperative (Neoadjuvant) therapy. These include the risk of delaying curative surgical resection in scenarios of adverse events or treatment resistance. Also, the predictive value of surrogate markers of disease cure still needs robust verification. Finally, the body of published data is still limited compared to adjuvant therapy. Addressing these concerns with more large scale randomized controlled trials is needed.

The Role of Lymphadenectomy in Early-Stage NSCLC

Lung cancer remains the leading cause of cancer-related death worldwide. The involvement of lymph nodes by the tumor has a strong impact on survival of patients. For this reason, lymphadenectomy plays a crucial role in the staging and prognosis of NSCLC, to define the most appropriate therapeutic strategies concerning the stage of the disease. To date, the benefit, in terms of survival, of the different extents of lymphadenectomy remains controversial in the scientific community. It is recognized that metastatic involvement of mediastinal lymph nodes in lung cancer is one of the most significant prognostic factors, in terms of survival, and it is therefore mandatory to identify patients with lymph node metastases who may benefit from adjuvant therapies, to prevent distant disease and local recurrences. The purpose of this review is to evaluate the role of lymphadenectomy in early-stage NSCLC in terms of efficacy and accuracy, comparing systematic, sampling, and lobe-specific lymph node dissection and analyzing the existing critical issue, through a search of the most relevant articles published in the last decades.

Prognostic Relevance of Negative Lymph Node Count in Resected Stage I-IIIa Small-cell Lung Cancer

OBJECTIVES

The prognostic significance of the negative lymph node (NLN) count has been confirmed in various cancers but not in small-cell lung cancer (SCLC). We aimed to evaluate the correlation between the NLN count and the prognosis of patients with stages I-IIIa SCLC who underwent lobectomy.

METHODS

Data on the clinical characteristics of SCLC patients who underwent lobectomy between 2000 and 2019 were collected from the SEER database and organized based on the X-tile plots to identify the optimal cutoff point for the NLN count. Kaplan-Meier curves and a Cox proportional hazard model were used to evaluate the prognostic factors for overall survival (OS) and lung cancer-specific survival.

RESULTS

Based on the X-tile plot-determined cutoff points of 3 and 7, the participants were grouped into the low (<3), middle (3-7), and high (>7) NLN subgroups for the analysis of OS. Univariable analysis showed that a higher NLN count correlated with more favorable OS and lung cancer-specific survival (both P <0.001). Multivariate analysis demonstrated that, after adjustment for related factors, the NLN count was positively associated with the prognosis and might thus be an independent risk factor for prognosis. Subgroup analyses revealed that, among different LN statuses and varied positive LN counts, the NLN count could predict the prognosis independently.

CONCLUSIONS

Higher NLNs correlated with better survival for patients who underwent lobectomy of stages I-IIIa SCLC. A predictive marker that combines the NLN count with the N stage and positive LN count could provide more prognostic information in SCLC.

Long noncoding RNA POU6F2-AS2 contributes to the aggressiveness of nonsmall-cell lung cancer via microRNA-125b-5p-mediated E2F3 upregulation

The role of the majority of long noncoding RNAs (lncRNAs) in the progression of nonsmall-cell lung cancer (NSCLC) remains elusive, despite their potential value, thus warranting in-depth studies. For example, detailed functions of the lncRNA POU6F2 antisense RNA 2 (POU6F2-AS2) in NSCLC are unknown. Herein, we investigated the expression status of POU6F2-AS2 in NSCLC. Furthermore, we systematically delineated the biological roles of POU6F2-AS2 in NSCLC alongside its downstream molecular events. We measured the expression levels of POU6F2-AS2 using quantitative real-time polymerase chain reaction and performed a series of functional experiments to address its regulatory effects in NSCLC cells. Using bioinformatic platforms, RNA immunoprecipitation, luciferase reporter assays, and rescue experiments, we investigated the potential mechanisms of POU6F2-AS2 in NSCLC. Subsequently, we confirmed the remarkable overexpression of POU6F2-AS2 in NSCLC using The Cancer Genome Atlas database and our own cohort. Functionally, inhibiting POU6F2-AS2 decreased NSCLC cell proliferation, colony formation, and motility, whereas POU6F2-AS2 overexpression exhibited contrasting effects. Mechanistically, POU6F2-AS2 acts as an endogenous decoy for microRNA-125b-5p (miR-125b-5p) in NSCLC that causes the overexpression of the E2F transcription factor 3 (E2F3). Moreover, suppressing miR-125b-5p or increasing E2F3 expression levels sufficiently recovered the anticarcinostatic activities in NSCLC induced by POU6F2-AS2 silencing. Thus, POU6F2-AS2 aggravates the oncogenicity of NSCLC by targeting the miR-125b-5p/E2F3 axis. Our findings suggest that POU6F2-AS2 is a novel therapeutic target for NSCLC.

Sentinel Lymph Node in Non-Small Cell Lung Cancer: Assessment of Feasibility and Safety by Near-Infrared Fluorescence Imaging and Clinical Consequences

Occult micrometastases can be missed by routine pathological analysis. Mapping of the pulmonary lymphatic system by near-infrared (NIR) fluorescence imaging can identify the first lymph node relay. This sentinel lymph node (SLN) can be analyzed by immunohistochemistry (IHC), which may increase micrometastasis detection and improve staging. This study analyzed the feasibility and safety of identifying SLNs in thoracic surgery by NIR fluorescence imaging in non-small cell lung cancer (NSCLC). This was a prospective, observational, single-center study. Eighty adult patients with suspected localized stage NSCLC (IA1 to IIA) were included between December 2020 and May 2022. All patients received an intraoperative injection of indocyanine green (ICG) directly in the peri tumoural area or by electromagnetic navigational bronchoscopy (ENB). The SLN was then assessed using an infrared fluorescence camera. SLN was identified in 60 patients (75%). Among them, 36 SLNs associated with a primary lung tumor were analyzed by IHC. Four of them were invaded by micrometastases (11.1%). In the case of pN0 SLN, the rest of the lymphadenectomy was cancer free. The identification of SLNs in thoracic surgery by NIR fluorescence imaging seems to be a feasible technique for improving pathological staging.

Circ_0002476 regulates cell growth, invasion, and mtDNA damage in non-small cell lung cancer by targeting miR-1182/TFAM axis

BACKGROUND

Many circular RNAs (circRNAs) have been identified as potential targets for cancer therapy. However, the role of circ_0002476 in non-small cell lung cancer (NSCLC) progression has not been explored.

METHODS

The expression levels of circ_0002476, microRNA (miR)-1182, and mitochondrial transcription factor A (TFAM) were detected by quantitative real-time polymerase chain reaction. Cell functions were measured by cell counting kit 8 assay, EdU assay, colony formation assay, flow cytometry and transwell assay. Mitochondrial DNA (mtDNA) damage was assessed by measuring mtDNA copy number and transcript levels of ND1 and ATP6. Protein expression was examined by western blot. The interaction between miR-1182 and circ_0002476 or TFAM was detected by dual-luciferase reporter assay and RNA pull-down assay. Animal experiments were performed to explore circ_0002476 role in vivo. Exosomes (Exs) were extracted and identified by transmission electron microscopy and nanoparticle tracking analysis.

RESULTS

Circ_0002476 was overexpressed in NSCLC tissues and cells. Circ_0002476 knockdown suppressed NSCLC cell proliferation and invasion, while promoted apoptosis and mtDNA damage. Circ_0002476 could sponge miR-1182, and miR-1182 inhibitor reversed the influence induced by circ_0002476 knockdown. Moreover, TFAM was targeted by miR-1182, and miR-1182 hindered NSCLC cell progression by regulating TFAM. Additionally, circ_0002476 silencing could reduce NSCLC tumor growth by miR-1182/TFAM. Further analyzed showed that Exs were involved in the transport of circ_0002476 between cells.

CONCLUSION

Taken together, our findings suggested that circ_0002476 might be a potential molecular target for NSCLC treatment.