Long Noncoding RNA H19 Facilitates Small Cell Lung Cancer Tumorigenesis Through miR-140-5p/FGF9 Axis

Prognostic biomarker MICAL2 and associates with proliferation, migration and immune infiltration in pancreatic adenocarcinoma

To elucidate the crucial function of MICAL2 as a potential immunotherapeutic target and a predictive biomarker in PAAD. The expression of MICAL2 in pan-cancer was investigated using public database, and the expression of MICAL2 in PAAD was validated using tissue samples. The diagnostic and prognostic significance of MICAL2 in PAAD was assessed through the application of ROC curves and Kaplan-Meier curves. The correlation between MICAL2 and infiltrating immune cells and immune checkpoints in PAAD was researched using the TIMER and TCGA databases. In vitro studies involved the evaluation of the biological functions of MICAL2 in human PAAD cells through the knockdown of MICAL2 expression using shRNA. Compared to corresponding normal tissues, the expression of MICAL2 exhibits significant differences in various cancers. Specifically, the level of MICAL2 expression is significantly increased in PAAD. Moreover, MICAL2 demonstrates considerable diagnostic potential in PAAD patients, and its elevated expression is indicative of an unfavorable prognosis. The differential expression of MICAL2 is related to infiltrating immune cells, immune cell markers, and immune checkpoints in PAAD. In ASPC-1 and PANC-1 cells, when MICAL2 was knocked down, there was a notable suppression of proliferation, migration, and invasion. MICAL2 functions as a significant predictor and promising immunotherapeutic target for prognosis assessment in PAAD. It has a pivotal function in fostering the growth and migration of PAAD cells.

LncRNA H19 Activates the RAS-MAPK Signaling Pathway via miR-140-5p/SOS1 Axis in Malignant Liver Tumors

OBJECTIVE

To study the influences of LncRNA H19 (H19) on malignant liver tumor cells and elucidate the underlying molecular mechanisms.

METHODS

H19 expression in liver tumor tissues, matched normal liver tissues, human liver malignant tumor cell lines and the human hepatocyte line LO2 was assessed via quantitative RT-PCR. Cell viability analysis and Matrigel invasion analysis were performed to evaluate the effects of H19 on cell proliferation and invasion. Luciferase reporter analysis was carried out to assess the interaction between miR-140-5p and SOS Ras/Rac guanine nucleotide exchange factor 1 (SOS1). The influence of H19 on the Ras-MAPK signalling pathway was evaluated by detecting key protein levels via active Ras pull-down analysis and Western blot analysis.

RESULTS

H19 expression was lower in liver cancer samples than in matched normal liver tissue samples. H19 overexpression enhanced the proliferation and invasion of HepG2 and SMMC-7721 cells. H19 overexpression increased the level of activated Ras. The expression levels of phosphorylated Raf, phosphorylated ERK and phosphorylated MEK were increased by H19 overexpression. H19 knockdown had the opposite effect. Treatment with a MAPK inhibitor significantly reversed the influence of H19 overexpression on liver malignant tumor cell growth and invasion. The MAPK activator reversed the opposing effects of H19 silencing. H19 overexpression increased the protein level of SOS1, and miR-140-5p directly targeted SOS1.

CONCLUSION

H19 can activate the Ras-MAPK signalling pathway via the miR-140-5p/SOS1 axis in malignant liver tumour cells.

lncRNAs'p potential roles in the pathogenesis of cancer via interacting with signaling pathways; special focus on lncRNA-mediated signaling dysregulation in lung cancer

Lung cancer ranks among the most lethal types of cancer globally, with a high occurrence and fatality rate. The spread of cancer to other parts of the body, known as metastasis, is the primary cause of treatment failure and death in lung cancer cases. Current approaches for treating advanced lung cancer typically involve a combination of chemotherapy and targeted therapy. However, the majority of patients ultimately develop resistance to these treatments, leading to a worsened prognosis. In recent years, cancer biology research has predominantly focused on the role of protein-encoding genes in cancer development. Long non-coding RNAs (lncRNAs) are transcripts over 200 nucleotides in length that do not encode proteins but are crucial RNA molecules involved in numerous biological functions. While many functions of lncRNAs remain unknown, some have been linked to human diseases, including cancer. Studies have demonstrated that lncRNAs interact with other large molecules in the cell, such as proteins, DNA, and RNA, influencing various critical aspects of cancer. LncRNAs play a significant role in regulating gene expression and have a crucial function in the transcriptional regulation of cancer cells. They mediate various biological and clinical processes such as invasion, metastasis, apoptosis, and cell proliferation. Dysregulation of lncRNAs has been found to impact the process of carcinogenesis through advanced technologies like RNA sequencing and microarrays. Collectively, these long non-coding RNAs hold promise as potential biomarkers and therapeutic targets for human cancers. In this segment, we provide a comprehensive summary of the literature on the characteristics and formation of lncRNAs, along with an overview of their current known roles in lung cancer.

Umbilical cord mesenchymal stem cells and lung cancer: We should be hopeful or hopeless?

Lung cancer (LC) is one of the leading causes of cancer-caused death that possesses a poor prognosis and low survival rate worldwide. In general, LC is classified into small-cell (SCLC) and non-small-cell carcinoma (NSCLC) (involving 80% of patients). Although chemotherapy, radiotherapy, surgery, and molecular-targeted therapy are considered standard approaches for LC treatment, these options have low success with detrimental effects on the life quality of patients. Ergo, recommending treatment with maximum effectiveness and minimum side effects for LC patients has been a substantial challenge for researchers and clinicians in the present era. Recently, mesenchymal stem cells (MSCs)-based strategies have sparked much interest in preventing or treating numerous illnesses. These multipotent stem cells can be isolated from diverse sources, such as umbilical cord, bone marrow, and adipose tissue. Among these sources, umbilical cord mesenchymal stem cells (UC-MSCs) have been in the spotlight of MSCs-based therapies thanks to their considerable advantages, such as high proliferation ability, low immune reactions and tumorigenesis, and easiness in collection and isolation. Some experimental studies have investigated the functionality of intact UC-MSCs and extracellular vesicles, exosomes, and conditioned medium derived from UC-MSCs, as well as genetically engineered UC-MSCs. In this review, we aimed to highlight the influences of these UMSCs-based methods in LC treatment with cellular and molecular insights.

Emerging roles of long noncoding RNA H19 in human lung cancer

Lung cancer holds the position of being the primary cause of cancer-related fatalities on a global scale. Furthermore, it exhibits the highest mortality rate among all types of cancer. The survival rate within a span of 5 years is less than 20%, primarily due to the fact that the disease is often diagnosed at an advanced stage, resulting in less effective treatment options compared to earlier stages. There are two main types of primary lung cancer: nonsmall-cell lung cancer, which accounts for approximately 80%-85% of all cases, and small-cell lung cancer, which is categorized based on the specific type of cells in which the cancer originates. The understanding of the biology of this disease and the identification of oncogenic driver alterations have significantly transformed the landscape of therapeutic approaches. Long noncoding RNAs (lncRNAs) play a crucial role in regulating various physiological and pathological processes through diverse molecular mechanisms. Among these lncRNAs, lncRNA H19, initially identified as an oncofetal transcript, has garnered significant attention due to its elevated expression in numerous tumors. Extensive research has confirmed its involvement in tumorigenesis and malignant progression by promoting cell growth, invasion, migration, epithelial-mesenchymal transition, metastasis, and therapy resistance. This comprehensive review aims to provide an overview of the aberrant overexpression of lncRNA H19 and the molecular pathways through which it contributes to the advancement of lung cancer. The findings of this review highlight the potential for further investigation into the diagnosis and treatment of this disease, offering promising avenues for future research.

Advances in applications of artificial intelligence algorithms for cancer-related miRNA research

MiRNAs are a class of small non-coding RNAs, which regulate gene expression post-transcriptionally by partial complementary base pairing. Aberrant miRNA expressions have been reported in tumor tissues and peripheral blood of cancer patients. In recent years, artificial intelligence algorithms such as machine learning and deep learning have been widely used in bioinformatic research. Compared to traditional bioinformatic tools, miRNA target prediction tools based on artificial intelligence algorithms have higher accuracy, and can successfully predict subcellular localization and redistribution of miRNAs to deepen our understanding. Additionally, the construction of clinical models based on artificial intelligence algorithms could significantly improve the mining efficiency of miRNA used as biomarkers. In this article, we summarize recent development of bioinformatic miRNA tools based on artificial intelligence algorithms, focusing on the potential of machine learning and deep learning in cancer-related miRNA research.

Critical roles of long noncoding RNA H19 in cancer

Long noncoding RNAs (lncRNAs) are a category of noncoding RNAs characterized by their length, often exceeding 200 nucleotides. There is a growing body of data that indicate the significant involvement of lncRNAs in a wide range of disorders, including cancer. lncRNA H19 was among the initial lncRNAs to be identified and is transcribed from the H19 gene. The H19 lncRNA exhibits significant upregulation in a diverse range of human malignancies, such as breast, colorectal, pancreatic, glioma, and gastric cancer. Moreover, the overexpression of H19 is frequently associated with a worse prognosis among individuals diagnosed with cancer. H19 has been shown to have a role in facilitating several cellular processes, including cell proliferation, invasion, migration, epithelial-mesenchymal transition, metastasis, and apoptosis. This article summarizes the aberrant upregulation of H19 in human malignancies, indicating promising avenues for future investigations on cancer diagnostics and therapeutic interventions.

Long noncoding RNA (lncRNA) H19: An essential developmental regulator with expanding roles in cancer, stem cell differentiation, and metabolic diseases

Recent advances in deep sequencing technologies have revealed that, while less than 2% of the human genome is transcribed into mRNA for protein synthesis, over 80% of the genome is transcribed, leading to the production of large amounts of noncoding RNAs (ncRNAs). It has been shown that ncRNAs, especially long non-coding RNAs (lncRNAs), may play crucial regulatory roles in gene expression. As one of the first isolated and reported lncRNAs, H19 has gained much attention due to its essential roles in regulating many physiological and/or pathological processes including embryogenesis, development, tumorigenesis, osteogenesis, and metabolism. Mechanistically, H19 mediates diverse regulatory functions by serving as competing endogenous RNAs (CeRNAs), Igf2/H19 imprinted tandem gene, modular scaffold, cooperating with H19 antisense, and acting directly with other mRNAs or lncRNAs. Here, we summarized the current understanding of H19 in embryogenesis and development, cancer development and progression, mesenchymal stem cell lineage-specific differentiation, and metabolic diseases. We discussed the potential regulatory mechanisms underlying H19's functions in those processes although more in-depth studies are warranted to delineate the exact molecular, cellular, epigenetic, and genomic regulatory mechanisms underlying the physiological and pathological roles of H19. Ultimately, these lines of investigation may lead to the development of novel therapeutics for human diseases by exploiting H19 functions.

Silencing of Long Non-coding RNA H19 Alleviates Lipopolysaccharide (LPS)-induced Apoptosis and Inflammation Injury by Regulating miR-140-5p/TLR4 Axis in Cell Models of Pneumonia

OBJECTIVE

Mounting studies have clarified the link between long non-coding RNAs (lncRNAs) and pneumonia. This research aims to probe the function and regulatory mechanism of lncRNA H19 in lipopolysaccharide (LPS)-induced cell models of pneumonia.

METHODS

WI-38 cells were exposed to LPS for 12 h to mimic cell models of pneumonia. The relative expression of H19, miR-140-5p, and toll-like receptor 4 (TLR4) were detected by quantitative real-time polymerase chain reaction (qRT-PCR). The cell viability was detected by MTT assay. The protein expression of apoptosis-associated proteins (Bax and Bcl-2) and TLR4 were determined by western blot. Moreover, the content of interleukin (IL)-6, IL-1β, and tumor necrosis factor (TNF)-α were measured by enzyme-linked immunosorbent assay (ELISA). The target relationship between miR- 140-5p and H19/ TLR4 was confirmed by Dual luciferase reporter (DLR) assay.

RESULTS

LncRNA H19 and TLR4 were up-regulated, while miR-140-5p was downregulated in peripheral blood of patients with pneumonia and LPS-treated WI-38 cells compared with their controls. Silencing of H19 or miR-140-5p mimics facilitated cell viability, whereas repressed apoptosis and reduced content of TNF-α, IL-6, and IL-1β in LPS-induced WI-38 cells. H19 targeted miR-140-5p and it inversely regulated miR-140- 5p expression. MiR-140-5p targeted TLR4 and it inversely regulated TLR4 expression. H19 positively regulated TLR4 expression. Moreover, inhibition of miR-140-5p or overexpression of TLR4 reversed the effects of H19 silencing on cell viability, inflammation, and apoptosis in LPS-induced WI-38 cells.

CONCLUSION

Silencing of H19 inhibited apoptosis and inflammation by miR-140- 5p/TLR4 pathway in LPS-induced WI-38 cells.

Repression of linc01555 up-regulates angiomotin-p130 via the microRNA-122-5p/clic1 axis to impact vasculogenic mimicry-mediated chemotherapy resistance in small cell lung cancer

Long non-coding ribonucleic acid 01555 (linc01555) is a brand-new long non-coding RNA (lncRNA) that acts a carcinogenic function in various cancers. However, its role in small cell lung cancer (SCLC) is uncertain. This research was to figure out the role of linc01555 in cisplatin (DDP) resistance of SCLC cells and its possible latent mechanism. After establishment of the resistant sub-strain H446/DDP or DMS-53/DDP, detection of linc01555, microRNA (miR)-122-5p and CLICl was done in the H446/DDP or DMS-53/DDP cell line. After intervention, cell biological functions were determined, as well as tube formation ability. The detection of angiomotin (Amot)-p130 and the validation of the regulatory mechanism were performed. Furthermore, tumor xenografts were applied in nude mice to evaluate the effect of linc01555 on DDP resistance in SCLC in vivo. Linc01555 was elevated in SCLC tissues and cells, and in H446/DDP cells or DMS-53/DDP vs. its parental cells; Restraining linc01555 or elevating miR-122-5p repressed the proliferation and metastasis of H446/DDP or DMS-53/DDP cells and vasculogenic mimicry (VM) formation. CLIC1 mediated miR-122-5p to influence the occurrence and development of SCLC. Linc01555 competitively combined with miR-122-5p, which targeted CLIC1. Refrained linc01555 elevated Amot-p130 via the miR-122-5p/CLIC1 axis. Reduced linc01555 refrained tumor growth and DDP resistance in vivo.In short, linc01555 may cause changes in DDP resistance via miR-122-5p/CLIC1 in SCLC. The finding may offer drug targets for SCLC resistance.

Targeting non-coding RNA H19: A potential therapeutic approach in pulmonary diseases

Non-coding RNA is still one of the most popular fields in biology research. In recent years, people paid more attention to the roles of H19 in lung diseases, which expressed abnormally in various pathological process. Therefore, this review focus on the regulatory role of H19 in asthma, pulmonary arterial hypertension (PAH), idiopathic pulmonary fibrosis (IPF), lung injury, pneumonia, lung cancer, etc. And the potential therapeutic agents and molecular treatments of H19 are collected. The aim is to demonstrate its underlying mechanism in pulmonary diseases and to guide the basic research targeting H19 into clinical drug translation.

Long non-coding RNA (lncRNA) H19 in human cancer: From proliferation and metastasis to therapy

Initiation and development of cancer depend on multiple factors that mutations in genes and epigenetic level can be considered as important drivers. Epigenetic factors include a large family of members and understanding their function in cancer has been a hot topic. LncRNAs are RNA molecules with no capacity in synthesis of proteins, and they have regulatory functions in cells. LncRNAs are localized in nucleus and cytoplasm, and their abnormal expression is related to development of tumor. This manuscript emphasizes on the role of lncRNA H19 in various cancers and its association with tumor hallmarks. The function of lncRNA H19 in most tumors is oncogenic and therefore, tumor cells increase its expression for promoting their progression. LncRNA H19 contributes to enhancing growth and cell cycle of cancers and by EMT induction, it is able to elevate metastasis rate. Silencing H19 induces apoptotic cell death and disrupts progression of tumors. LncRNA H19 triggers chemo- and radio-resistance in cancer cells. miRNAs are dually upregulated/down-regulated by lncRNA H19 in increasing tumor progression. Anti-cancer agents reduce lncRNA H19 in impairing tumor progression and increasing therapy sensitivity. A number of downstream targets and molecular pathways for lncRNA H19 have been detected in cancers including miRNAs, RUNX1, STAT3, β-catenin, Akt2 and FOXM1. Clinical studies have revealed potential of lncRNA H19 as biomarker and its association with poor prognosis. LncRNA H19 can be transferred to cancer cells via exosomes in enhancing their progression.

New developments in the biology of fibroblast growth factors

The fibroblast growth factor (FGF) family is composed of 18 secreted signaling proteins consisting of canonical FGFs and endocrine FGFs that activate four receptor tyrosine kinases (FGFRs 1-4) and four intracellular proteins (intracellular FGFs or iFGFs) that primarily function to regulate the activity of voltage-gated sodium channels and other molecules. The canonical FGFs, endocrine FGFs, and iFGFs have been reviewed extensively by us and others. In this review, we briefly summarize past reviews and then focus on new developments in the FGF field since our last review in 2015. Some of the highlights in the past 6 years include the use of optogenetic tools, viral vectors, and inducible transgenes to experimentally modulate FGF signaling, the clinical use of small molecule FGFR inhibitors, an expanded understanding of endocrine FGF signaling, functions for FGF signaling in stem cell pluripotency and differentiation, roles for FGF signaling in tissue homeostasis and regeneration, a continuing elaboration of mechanisms of FGF signaling in development, and an expanding appreciation of roles for FGF signaling in neuropsychiatric diseases. This article is categorized under: Cardiovascular Diseases > Molecular and Cellular Physiology Neurological Diseases > Molecular and Cellular Physiology Congenital Diseases > Stem Cells and Development Cancer > Stem Cells and Development.

Analysis of lung cancer-related genetic changes in long-term and low-dose polyhexamethylene guanidine phosphate (PHMG-p) treated human pulmonary alveolar epithelial cells

BACKGROUND

Lung injury elicited by respiratory exposure to humidifier disinfectants (HDs) is known as HD-associated lung injury (HDLI). Current elucidation of the molecular mechanisms related to HDLI is mostly restricted to fibrotic and inflammatory lung diseases. In our previous report, we found that lung tumors were caused by intratracheal instillation of polyhexamethylene guanidine phosphate (PHMG-p) in a rat model. However, the lung cancer-related genetic changes concomitant with the development of these lung tumors have not yet been fully defined. We aimed to discover the effect of long-term exposure of PHMG-p on normal human lung alveolar cells.

METHODS

We investigated whether PHMG-p could increase distorted homeostasis of oncogenes and tumor-suppressor genes, with long-term and low-dose treatment, in human pulmonary alveolar epithelial cells (HPAEpiCs). Total RNA sequencing was performed with cells continuously treated with PHMG-p and harvested after 35 days.

RESULTS

After PHMG-p treatment, genes with transcriptional expression changes of more than 2.0-fold or less than 0.5-fold were identified. Within 10 days of exposure, 2 protein-coding and 5 non-coding genes were selected, whereas in the group treated for 27-35 days, 24 protein-coding and 5 non-coding genes were identified. Furthermore, in the long-term treatment group, 11 of the 15 upregulated genes and 9 of the 14 downregulated genes were reported as oncogenes and tumor suppressor genes in lung cancer, respectively. We also found that 10 genes of the selected 24 protein-coding genes were clinically significant in lung adenocarcinoma patients.

CONCLUSIONS

Our findings demonstrate that long-term exposure of human pulmonary normal alveolar cells to low-dose PHMG-p caused genetic changes, mainly in lung cancer-associated genes, in a time-dependent manner.

Non-Coding RNAs: lncRNAs, miRNAs, and piRNAs in Sexual Development

Non-coding RNAs (ncRNAs) are a group of RNAs that do not encode functional proteins, including long non-coding RNAs (lncRNAs), microRNAs (miRNAs), PIWI-interacting RNAs (piRNAs), and short interfering RNAs (siRNAs). In the last 2 decades an effort has been made to uncover the role of ncRNAs during development and disease, and nowadays it is clear that these molecules have a regulatory function in many of the developmental and physiological processes where they have been studied. In this review, we provide an overview of the role of ncRNAs during gonad determination and development, focusing mainly on mammals, although we also provide information from other species, in particular when there is not much information on the function of particular types of ncRNAs during mammalian sexual development.

Overexpression of Long Noncoding RNA H19 Downregulates miR-140-5p and Activates PI3K/AKT Signaling Pathway to Promote Invasion, Migration and Epithelial-Mesenchymal Transition of Ovarian Cancer Cells

OBJECTIVE

The abnormal expression of LncRNA H19 and miR-140-5p has been linked to ovarian cancer (OC). Whether H19 directly regulates miR-140-5p in ovarian cancer cells has been unclear. In this study, we deeply explored the relationship between H19 and miR-140-5p in ovarian cancer and the mechanism of action in regulating OC progression.

METHODS

A total of 66 patients with OC admitted to the hospital from June 2017 to June 2019 were selected as the research group (RG), and meanwhile, 60 cases of healthy subjects were selected as the control group (CG). In addition, OC cells and normal ovarian epithelial cells were used to detect H19 and miR-140-5p expression levels and to analyze the effect of H19 on OC cells. The activation of the PI3K/AKT pathway and downstream proteins were analyzed by western blot.

RESULTS

H19 was highly expressed while miR-140-5p was lowly expressed in OC patients and cell lines (P < 0.050). The proliferation, invasion, migration ability, and epithelial-mesenchymal transition (EMT) of OC cells were reduced after inhibiting H19 expression, and the apoptosis rate was increased. Transfection of cells with miR-140-5p mimics brought opposite effects. Online prediction and dual-luciferase reporter (DLR) confirmed that H19 directly binds miR-140-5p. Western blot assay indicated overexpression activated the PI3K/AKT signaling pathway in OC cells. Moreover, overexpression promoted tumor growth in nude mice and was suppressed by PI3K inhibitor.

CONCLUSION

LncRNA H19 downregulation of miR-140-5p to activate the PI3K/AKT signaling pathway and promote the proliferation, invasion, migration and EMT of OC.

Upregulation of FGF9 in Lung Adenocarcinoma Transdifferentiation to Small Cell Lung Cancer

Transdifferentiation of lung adenocarcinoma to small cell lung cancer (SCLC) has been reported in a subset of lung cancer cases that bear EGFR mutations. Several studies have reported the prerequisite role of TP53 and RB1 alterations in transdifferentiation. However, the mechanism underlying transdifferentiation remains understudied, and definitive additional events, the third hit, for transdifferentiation have not yet been identified. In addition, no prospective experiments provide direct evidence for transdifferentiation. In this study, we show that FGF9 upregulation plays an essential role in transdifferentiation. An integrative omics analysis of paired tumor samples from a patient with transdifferentiated SCLC exhibited robust upregulation of FGF9. Furthermore, FGF9 upregulation was confirmed at the protein level in four of six (66.7%) paired samples. FGF9 induction transformed mouse lung adenocarcinoma-derived cells to SCLC-like tumors in vivo through cell autonomous activation of the FGFR pathway. In vivo treatment of transdifferentiated SCLC-like tumors with the pan-FGFR inhibitor AZD4547 inhibited growth. In addition, FGF9 induced neuroendocrine differentiation, a pathologic characteristic of SCLC, in established human lung adenocarcinoma cells. Thus, the findings provide direct evidence for FGF9-mediated SCLC transdifferentiation and propose the FGF9-FGFR axis as a therapeutic target for transdifferentiated SCLC. SIGNIFICANCE: This study demonstrates that FGF9 plays a role in the transdifferentiation of lung adenocarcinoma to small cell lung cancer.

NSE, positively regulated by LINC00657-miR-93-5p axis, promotes small cell lung cancer (SCLC) invasion and epithelial-mesenchymal transition (EMT) process

Background: Neuron specific enolase (NSE) is a specific biomarker for SCLC. However, the biological roles and aberrant expression of NSE in SCLC have not been well illustrated. Methods: The expression of NSE, miR-93-5p and LINC00657 in SCLC tissues and cell lines were detected using real time quantitative PCR (qRT-PCR) or immunohistochemistry. CCK8 assay was performed to detect cell proliferation. Cell migration and invasion capabilities were investigated by transwell assay. Epithelial-mesenchymal transition (EMT) process was verified by detecting epithelial marker E-cadherin and mesenchymal marker N-cadherin. The direct interactions between miR-93-5p and NSE or LINC00657 were predicted by bioinformatics tools and verified using dual luciferase reporter assay. Results: Upregulated expression of NSE in SCLC tumor tissues were positively associated with advanced tumor stage, distant metastasis and poor overall survival. Overexpression of NSE promoted cell proliferation, migration, invasion and EMT in SCLC cells, while silence of NSE inhibited these effects. Mechanically, NSE expression was positively correlated with LINC00657, and negatively correlated with miR-93-5p. Moreover, NSE was positively regulated by LINC00657 through sponging of miR-93-5p. LINC00657 and miR-93-5p promoted SCLC cell migration, invasion and EMT by NSE-mediated manner. Conclusion: Overall, our study revealed a novel role of NSE in SCLC. NSE was positively regulated by LINC00657 through competitively interacting with miR-93-5p, which may be potential targets for SCLC patients.

Interferon-Induced Transmembrane Protein 1 (IFITM1) Promotes Distant Metastasis of Small Cell Lung Cancer

Small cell lung cancer (SCLC) is a severe malignancy associated with early and widespread metastasis. To study SCLC metastasis, we previously developed an orthotopic transplantation model using the human SCLC cell line DMS273. In the model, metastatic foci were found in distant tissues such as bone and the adrenal gland, similarly as observed in patients with SCLC. In this study, we evaluated the differentially expressed genes between orthotopic and metastatic tumors in the model. We isolated tumor cells from orthotopic and metastatic sites, and the tumor cell RNA was analyzed using DNA microarray analysis. We found that 19 genes in metastatic tumors were upregulated by more than 4-fold compared with their expression in orthotopic tumors. One of these genes encodes a transmembrane protein, interferon (IFN)-induced transmembrane protein 1 (IFITM1), and immunohistochemical analysis confirmed the higher expression of the protein in metastatic sites than in orthotopic sites. IFITM1 was also detected in some SCLC cell lines and lung tumors from patients with SCLC. The overexpression of IFITM1 in DMS273 cells increased their metastatic formation in the orthotopic model and in an experimental metastasis model. Conversely, the silencing of IFITM1 suppressed metastatic formation by DMS273 cells. We also found that IFITM1 overexpression promoted the metastatic formation of NCI-H69 human SCLC cells. These results demonstrate that IFITM1 promotes distant metastasis in xenograft models of human SCLC.