BACKGROUND: Lung cancer is a major threat to human health. The molecular mechanisms related to the occurrence and development of lung cancer are complex and poorly known. Exploring molecular markers related to the development of lung cancer is helpful to improve the effect of early diagnosis and treatment. Long non-coding RNA (lncRNA) THAP7-AS1 is known to be highly expressed in gastric cancer, but has been less studied in other cancers. The aim of the study is to explore the role and mechanism of methyltransferase-like 3 (METTL3) mediated up-regulation of N6-methyladenosine (m6A) modified lncRNA THAP7-AS1 expression in promoting the development of lung cancer. METHODS: Samples of 120 lung cancer and corresponding paracancerous tissues were collected. LncRNA microarrays were used to analyze differentially expressed lncRNAs. THAP7-AS1 levels were detected in lung cancer, adjacent normal tissues and lung cancer cell lines by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The diagnostic value of THAP7-AS1 in lung cancer and the relationship between THAP7-AS1 expression and survival rate and clinicopathological parameters were analyzed. Bioinformatics analysis, methylated RNA immunoprecipitation (meRIP), RNA pull-down and RNA-immunoprecipitation (RIP) assay were used to investigate the molecular regulation mechanism of THAP7-AS1. Cell proliferation, migration, invasion and tumorigenesis of SPC-A-1 and NCI-H1299 cells were determined by MTS, colony-formation, scratch, Transwell and xenotransplantation in vivo, respectively. Expression levels of phosphoinositide 3-kinase/protein kenase B (PI3K/AKT) signal pathway related protein were detected by Western blot. RESULTS: Expression levels of THAP7-AS1 were higher in lung cancer tissues and cell lines (P<0.05). THAP7-AS1 has certain diagnostic value in lung cancer [area under the curve (AUC)=0.737], and its expression associated with overall survival rate, tumor size, tumor-node-metastasis (TNM) stage and lymph node metastasis (P<0.05). METTL3-mediated m6A modification enhanced THAP7-AS1 expression. The cell proliferation, migration, invasion and the volume and mass of transplanted tumor were all higher in the THAP7-AS1 group compared with the NC group and sh-NC group of SPC-A-1 and NCI-H1299 cells, while the cell proliferation, migration and invasion were lower in the sh-THAP7-AS1 group (P<0.05). THAP7-AS1 binds specifically to Cullin 4B (CUL4B). The cell proliferation, migration, invasion, and expression levels of phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA), phosphoinositide-3 kinase, catalytic subunit delta (PIK3CD), phospho-phosphatidylinositol 3-kinase (p-PI3K), phospho-protein kinase B (p-AKT) and phospho-mammalian target of rapamycin (p-mTOR) were higher in the THAP7-AS1 group compared with the Vector group of SPC-A-1 and NCI-H1299 cells (P<0.05). CONCLUSIONS LncRNA THAP7-AS1 is stably expressed through m6A modification mediated by METTL3, and combines with CUL4B to activate PI3K/AKT signal pathway, which promotes the occurrence and development of lung cancer.
Humans ; Lung Neoplasms/pathology* ; RNA, Long Noncoding/metabolism* ; Phosphatidylinositol 3-Kinases/metabolism* ; Up-Regulation ; Proto-Oncogene Proteins c-akt/metabolism* ; Cell Line, Tumor ; Cell Proliferation/genetics* ; Gene Expression Regulation, Neoplastic ; Methyltransferases/metabolism* ; Cullin Proteins/genetics*

Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) are currently the first-line standard of care for patients with non-small cell lung cancer (NSCLC) that harbor EGFR mutations. Nevertheless, resistance to EGFR-TKIs is inevitable. In recent years, although immune checkpoint inhibitors (ICIs) have significantly shifted the treatment paradigm in advanced NSCLC without driver mutation, clinical benefits of these agents are limited in patients with EGFR-mutated NSCLC. Compared with wild-type tumors, tumors with EGFR mutations show more heterogeneity in the expression level of programmed cell death ligand 1 (PD-L1), tumor mutational burden (TMB), and other tumor microenvironment (TME) characteristics. Whether ICIs are suitable for NSCLC patients with EGFR mutations is still worth exploring. In this review, we summarized the clinical data with regard to the efficacy of ICIs in patients with EGFR-mutated NSCLC and deciphered the unique TME in EGFR-mutated NSCLC.
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Humans ; Carcinoma, Non-Small-Cell Lung/genetics* ; Lung Neoplasms/genetics* ; ErbB Receptors/metabolism* ; Immunotherapy ; Mutation ; B7-H1 Antigen/genetics* ; Protein Kinase Inhibitors/pharmacology* ; Tumor Microenvironment

Objective: To investigate the clinicopathological features, treatment and prognosis of patients with RET fusion positive non-small cell lung cancer (NSCLC). Methods: A total of 1 089 NSCLCs were retrieved at Affiliated Hospital of Jiangnan University from August 2018 to April 2020. In all cases, multiple gene fusion detection kits (fluorescent PCR method) were used to detect the gene status of RET, EGFR, ALK, ROS1, KRAS, BRAF and HER2; and immunohistochemical method was used to detect the expression of PD-L1 and mismatch repair related proteins. The correlation between RET-fusion and patients' age, gender, smoking history, tumor stage, grade, pathologic type, and PD-L1, mismatch repair related protein expression was analyzed. Results: There were 22 cases (2.02%) detected with RET fusion-positive in 1 089 NSCLC patients, in which 11 males and 11 females; and the median age was 63.5 years. There were 20 adenocarcinomas, including 11 acinar predominant adenocarcinoma (APA), five solid predominant adenocarcinoma (SPA) and four lepidic predominant adenocarcinoma (LPA); There were one case each of squamous cell carcinoma (non-keratinizing type) and sarcomatoid carcinoma (pleomorphic carcinoma). There were 6 and 16 patients with RET fusion-positive who were in stage Ⅰ-Ⅱ and Ⅲ-Ⅳ respectively, and 16 cases with lymph node metastasis, 11 cases with distant metastasis. Among RET fusion-positive cases, one was detected with HER2 co-mutation. The tumor proportion score of PD-L1≥1% in patients with RET fusion positive lung cancer was 54.5% (12/22). Defects in mismatch repair protein expression were not found in patients with RET fusion positive NSCLC. Four patients with RET fusions positive (two cases of APA and two cases of SPA) received pratinib-targeted therapy, and two showed benefits from this targeted therapy. Conclusions: The histological subtypes of RET fusions positive NSCLC are more likely to be APA or SPA. RET fusion-positive NSCLC patients are associated with advanced clinical stage, lymph node metastases, and they may benefit from targeted therapy with RET-specific inhibitors.
Male ; Female ; Humans ; Middle Aged ; Carcinoma, Non-Small-Cell Lung/pathology* ; Lung Neoplasms/pathology* ; B7-H1 Antigen/genetics* ; Protein-Tyrosine Kinases/genetics* ; Proto-Oncogene Proteins c-ret/metabolism* ; Proto-Oncogene Proteins/genetics* ; Adenocarcinoma/pathology* ; Carcinoma, Squamous Cell/genetics* ; Mutation

BACKGROUND: There have been many significant advances in the diagnosis and treatment of non-small cell lung cancer (NSCLC). However, the mechanism underlying the progression of NSCLC is still not clear. Plant homodomain finger-like domain-containing protein 5A (PHF5A) plays an important role in processes of chromatin remodeling, morphological development of tissues and organs and maintenance of stem cell pluripotency. This study aims to investigate the role of PHF5A in the proliferation and migration of NSCLC. METHODS: A549 and PC-9 PHF5A overexpression cell lines were constructed. PHF5A expression was decreased in H292 and H1299 cells by using siRNA. Flow cytometry was used to detect the cell cycle. MTT assay and clone formation assay were used to examine the proliferative ability of NSCLC, while migration assay and wound healing assay were performed to evaluate the ability of migration. Western blot analysis was used to measure the expressions of PI3K, p-AKT and the associated downstream factors. RESULTS: Up-regulation of PHF5A in A549 and PC-9 cells increased the proliferation rate, while down-regulation of PHF5A in H292 and H1299 cells inhibited the proliferation rate at 24 h, 48 h and 72 h (P<0.05). The metastatic ability was elevated in the PHF5A-overexpresion groups, while reduced in the PHF5A-down-regulation group (P<0.05). In addition, reduced expression of PHF5A induced cell cycle arrest at G1/S phase (P<0.05). Furthermore, decreased expression of PHF5A reduced the expression levels of PI3K, phosphorylation of AKT, c-Myc (P<0.05) and elevated the expression of p21 (P<0.05). CONCLUSIONS These results demonstrated that PHF5A may play an important role in progression of NSCLC by regulating the PI3K/AKT signaling pathway.
Humans ; Carcinoma, Non-Small-Cell Lung/pathology* ; Lung Neoplasms/pathology* ; Proto-Oncogene Proteins c-akt/metabolism* ; Phosphatidylinositol 3-Kinases/metabolism* ; Cell Line, Tumor ; Cell Proliferation/genetics* ; Cell Movement/genetics* ; Gene Expression Regulation, Neoplastic ; Trans-Activators/genetics* ; RNA-Binding Proteins/metabolism*

The occurence and development of tumors is a complicated process, which not only depends on the mutation or deletion of genes, but also is affected by epigenetic regulation. Accumulating evidences have shown that epigenetic modifications play fundamental roles in transcriptional regulation, heterochromatin formation, X chromosome inactivation, DNA damage response and tumor development. SET domain containing lysine methyltransferase 7 (SETD7) was initially identified as an important lysine methyltransferase, which methylated histone and non-histone proteins. These modifications play fundamental roles. Once this modification disorders, it can directly lead to cell abnormalities and cause many diseases. Studies have shown that SETD7 is related to the occurence and development of various tumors, but the methylation sites of SETD7 and its regulatory mechanism have not been fully elucidated. This article summarizes the research progress of the role of SETD7 on histone and non-histone methylation modification in tumors and the molecular mechanism, in order to provide new therapeutic targets for tumor pathogenesis and diagnosis.
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Humans ; Epigenesis, Genetic ; Histone-Lysine N-Methyltransferase/metabolism* ; Lysine/metabolism* ; Lung Neoplasms/genetics* ; Histones/metabolism*

Lung squamous cell carcinoma (LSCC) accounts for approximately 30% of non-small cell lung cancer (NSCLC) cases and is the second most common histological type of lung cancer. Anaplastic lymphoma kinase (ALK)-positive NSCLC accounts for only 2%-5% of all NSCLC cases, and is almost exclusively detected in patients with lung adenocarcinoma. Thus, ALK testing is not routinely performed in the LSCC population, and the efficacy of such treatment for ALK-rearranged LSCC remains unknown. Echinoderm microtubule associated protein like 4 (EML4)-ALK (V1) and TP53 co-mutations were identified by next generation sequencing (NGS) in this patient with advanced LSCC. On December 3, 2020, Ensatinib was taken orally and the efficacy was evaluated as partial response (PR). The progression-free survival (PFS) was 19 months. When the disease progressed, the medication was changed to Loratinib. To our knowledge, Enshatinib created the longest PFS of ALK-mutant LSCC patients treated with targeted therapy since literature review. Herein, we described one case treated by Enshatinib involving a patient with both EML4-ALK and TP53 positive LSCC, and the relevant literatures were reviewed for discussing the treatment of this rare disease.
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Humans ; Carcinoma, Non-Small-Cell Lung/drug therapy* ; Lung Neoplasms/pathology* ; Anaplastic Lymphoma Kinase/metabolism* ; Carcinoma, Squamous Cell/genetics* ; Mutation ; Cytoskeletal Proteins/genetics* ; Lung/pathology* ; Oncogene Proteins, Fusion/genetics* ; Protein Kinase Inhibitors/therapeutic use* ; Tumor Suppressor Protein p53/genetics*

OBJECTIVE: To screen the differentially expressed long non-coding RNAs (lncRNAs) in non-small cell lung cancer (NSCLC) cells with acquired resistance to osimertinib and explore their roles in drug resistance of the cells. METHODS: The cell lines H1975_OR and HCC827_OR with acquired osimertinib resistance were derived from their osimertinib-sensitive parental NSCLC cell lines H1975 and HCC827, respectively, and their sensitivity to osimertinib was assessed with CCK-8 assay, clone formation assay and flow cytometry. RNA sequencing (RNA-seq) and real-time quantitative PCR (qPCR) were used to screen the differentially expressed lncRNAs in osimertinib-resistant cells. The role of the identified lncRNA in osimertinib resistance was explored using CCK-8, clone formation and Transwell assays, and its subcellular localization and downstream targets were analyzed by nucleoplasmic separation, bioinformatics analysis and qPCR. RESULTS: The resistance index of H1975_OR and HCC827_OR cells to osimertinib was 598.70 and 428.82, respectively (P < 0.001), and the two cell lines showed significantly increased proliferation and colony-forming abilities with decreased apoptosis (P < 0.01). RNA-seq identified 34 differentially expressed lncRNAs in osimertinib-resistant cells, and among them lnc-TMEM132D-AS1 showed the highest increase of expression after acquired osimertinib resistance (P < 0.01). Analysis of the TCGA database suggested that the level of lnc-TMEM132D-AS1 was significantly higher in NSCLC than in adjacent tissues (P < 0.001), and its high expression was associated with a poor prognosis of the patients. In osimertinib-sensitive cells, overexpression of Lnc-TMEM132D-AS1 obviously promoted cell proliferation, colony formation and migration (P < 0.05), while Lnc-TMEM132D-AS1 knockdown partially restored osimertinib sensitivity of the resistant cells (P < 0.01). Lnc-TMEM132D-AS1 was localized mainly in the cytoplasm, and bioinformatics analysis suggested that hsa-miR-766-5p was its candidate target, and their expression levels were inversely correlated. The target mRNAs of hsa-miR-766-5p were mainly enriched in the Ras signaling pathway. CONCLUSION The expression of lnc-TMEM132D-AS1 is significantly upregulated in NSCLC cells with acquired osimertinib resistance, and may serve as a potential biomarker and therapeutic target for osimertinibresistant NSCLC.
Humans ; Carcinoma, Non-Small-Cell Lung/metabolism* ; Lung Neoplasms/genetics* ; RNA, Long Noncoding/metabolism* ; Sincalide/metabolism* ; Cell Line, Tumor ; Cell Proliferation/genetics* ; Cell Movement ; MicroRNAs/genetics* ; Gene Expression Regulation, Neoplastic ; Membrane Proteins/metabolism*

NDFIP1 has been previously reported as a tumor suppressor in multiple solid tumors, but the function of NDFIP1 in NSCLC and the underlying mechanism are still unknown. Besides, the WW domain containing proteins can be recognized by NDFIP1, resulted in the loading of the target proteins into exosomes. However, whether WW domain-containing transcription regulator 1 (WWTR1, also known as TAZ) can be packaged into exosomes by NDFIP1 and if so, whether the release of this oncogenic protein via exosomes has an effect on tumor development has not been investigated to any extent. Here, we first found that NDFIP1 was low expressed in NSCLC samples and cell lines, which is associated with shorter OS. Then, we confirmed the interaction between TAZ and NDFIP1, and the existence of TAZ in exosomes, which requires NDFIP1. Critically, knockout of NDFIP1 led to TAZ accumulation with no change in its mRNA level and degradation rate. And the cellular TAZ level could be altered by exosome secretion. Furthermore, NDFIP1 inhibited proliferation in vitro and in vivo, and silencing TAZ eliminated the increase of proliferation caused by NDFIP1 knockout. Moreover, TAZ was negatively correlated with NDFIP1 in subcutaneous xenograft model and clinical samples, and the serum exosomal TAZ level was lower in NSCLC patients. In summary, our data uncover a new tumor suppressor, NDFIP1 in NSCLC, and a new exosome-related regulatory mechanism of TAZ.
Humans ; Carcinoma, Non-Small-Cell Lung/metabolism* ; Carrier Proteins/metabolism* ; Cell Line ; Cell Proliferation ; Exosomes/metabolism* ; Lung Neoplasms/genetics* ; Membrane Proteins/metabolism* ; Transcriptional Coactivator with PDZ-Binding Motif Proteins/metabolism*

BACKGROUND: Epidermal growth factor receptor (EGFR) gene mutations are the most common driver mutations in non-small cell lung cancer (NSCLC). To prolong the survival of the patients, EGFR tyrosine kinase inhibitors (TKIs) resistance in NSCLC is a major challenge that needs to be addressed urgently, and this study focuses on investigating the mechanism of cigarette smoke (CS) induced Gefitinib resistance in NSCLC. METHODS: PC-9 and A549 cells were cultured in vitro and treated with 1 µmol/L Gefitinib for 4 h and 10% cigarette smoke extract (CSE) for 48 h. Western blot was used to detect Sirtuin 3 (Sirt3) and superoxide dismutase 2 (SOD2) protein expressions; DCFH-DA probe was used to detect intracellular reactive oxygen species (ROS); CCK-8 kit was used to detect cell activity, and EdU was used to detect cell proliferation ability. Sirt3 overexpression plasmid (OV-Sirt3) was transfected in PC-9 and A549 cells and treated with 1 µmol/L Gefitinib for 4 h and 10% CSE for 48 h after N-acetylcysteine (NAC) action. The expressions of Sirt3 and SOD2 were detected by Western blot; the ROS level in the cells was detected by DCFH-DA probe, and the cell activity was detected by CCK-8. RESULTS: CSE induced an increase in the 50% inhibitory concentration (IC50) of both PC-9 and A549 cells to Gefitinib (P<0.01) and enhanced the proliferation of PC-9 and A549 cells, suggesting that CS induced Gefitinib resistance in NSCLC. ROS was involved in CSE-induced Gefitinib resistance (P<0.05). CSE induced low expressions of Sirt3 and SOD2 (P<0.01), and Sirt3/SOD2 was associated with poor prognosis in lung cancer patients (P<0.05). OV-Sirt3 in PC-9 and A549 cells reversed CSE-induced Gefitinib resistance (P<0.05) and significantly reduced ROS production. NAC reversed CSE-induced Gefitinib resistance in PC-9 and A549 cells (P<0.05). CONCLUSIONS The ROS/Sirt3/SOD2 pathway is involved in CS-induced Gefitinib resistance in NSCLC.
Humans ; Gefitinib/therapeutic use* ; Carcinoma, Non-Small-Cell Lung/metabolism* ; Sirtuin 3/therapeutic use* ; Lung Neoplasms/metabolism* ; Reactive Oxygen Species/therapeutic use* ; Antineoplastic Agents/therapeutic use* ; Cigarette Smoking ; Sincalide/therapeutic use* ; ErbB Receptors/metabolism* ; Drug Resistance, Neoplasm/genetics* ; Cell Line, Tumor

Spindle assembly checkpoint (SAC) is a protective mechanism for cells to undergo accurate mitosis. SAC prevented chromosome segregation when kinetochores were not, or incorrectly attached to microtubules in the anaphase of mitosis, thus avoiding aneuploid chromosomes in daughter cells. Aneuploidy and altered expression of SAC component proteins are common in different cancers, including lung cancer. Therefore, SAC is a potential new target for lung cancer therapy. Five small molecule inhibitors of monopolar spindle 1 (MPS1), an upstream component protein of SAC, have entered clinical trials. This article introduces the biological functions of SAC, summarizes the abnormal expression of SAC component proteins in various cancers and the research progress of MPS1 inhibitors, and expects to provide a reference for the future development of lung cancer therapeutic strategies targeting SAC components.
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Humans ; Cell Cycle Proteins/metabolism* ; Spindle Apparatus/metabolism* ; Protein Serine-Threonine Kinases/metabolism* ; M Phase Cell Cycle Checkpoints/genetics* ; Lung Neoplasms/metabolism*