Epithelial-mesenchymal Transition In Lung Adenocarcinoma Research Articles

JAM2 is a prognostic biomarker and inhibits proliferation, metastasis and epithelial-mesenchymal transition in lung adenocarcinoma.

Junctional adhesion molecule 2 (JAM2) plays a pivotal role in various biological processes, including proliferation, metastasis and angiogenesis, contributing to tumor progression. While previous studies have highlighted the polarizing functions of JAM2 in different cancer types, its specific role in lung adenocarcinoma (LUAD) remains unclear. In this study, we harnessed multiple public databases to analyze the expression and prognostic significance of JAM2 in LUAD. Using the Linkedomics database, Matescape database and R package, we explored the associated genes, the potential biological functions and the impact of JAM2 on the tumor microenvironment. Our findings from public databases were further validated using real-time quantitative PCR, western blot and immunohistochemistry. Additionally, in vitro experiments were conducted to assess the influence of JAM2 on LUAD cell proliferation, invasion, migration, apoptosis and epithelial-mesenchymal transition. Furthermore, we established a xenograft model to investigate the in vivo effects of JAM2 on tumorigenesis. Our results revealed a significant downregulation of JAM2 in LUAD, and patients with low JAM2 expression exhibited unfavorable overall survival outcomes. Functional enrichment analysis indicated that JAM2 may be associated with processes such as cell adhesion, extracellular matrix, cell junctions and regulation of proliferation. Notably, increased JAM2 expression correlated with higher tumor microenvironment scores and reduced immune cell abundance. Furthermore, overexpression of JAM2 induced apoptosis, suppressed tumor proliferation and exhibited potential inhibitory effects on tumor invasion and migration through the modulation of epithelial-mesenchymal transition. Additionally, in vivo experiments confirmed that JAM2 overexpression led to a reduction in tumor growth. Overall, our study highlights the clinical significance of low JAM2 expression as a predictor of poor prognosis in LUAD patients. Moreover, JAM2 was found to exert inhibitory effects on various aspects of tumor progression. Consequently, JAM2 emerges as a promising prognostic biomarker and a potential therapeutic target for LUAD patients.

Transcription factor SP1 and oncoprotein PPP1R13L regulate nicotine-induced epithelial-mesenchymal transition in lung adenocarcinoma via a feedback loop

Tobacco remains the most common environmental carcinogen leading to the occurrence and development of lung cancer. Nicotine, a tumor promoter in cigarette smoke, has been shown to induce epithelial-mesenchymal transition (EMT), a cellular program required for the invasion and metastasis in tumor cells. Specificity Protein 1 (SP1) is a well-characterized transcription factor that can regulate the EMT process via transcriptionally activating E-cadherin expression. Protein Phosphatase 1 Regulatory Subunit 13 Like (PPP1R13L) is a newly identified oncoprotein previously reported to inhibit the transcriptional activity of SP1 via a direct protein–protein interaction. To reveal the underlying implication of the interconnections between PPP1R13L and SP1 in the nicotine-induced EMT process, the present study established an EMT cell model of lung cancer using 1 μM of nicotine, a dose close to human exposure, in which an alternate fluctuation in the expression of PPP1R13L and SP1 was captured. Subsequently, the direct inhibition of SP1 by PPP1R13L was demonstrated to be a critical mechanism underlying the involvement of PPP1R13L in the nicotine-induced EMT process. More interestingly, SP1 was further shown to transcriptionally activate PPP1R13L expression in a feedback manner. In addition, PPP1R13L and SP1 expression was found to be closely associated with the clinicopathological characteristics of lung cancer patients. Here we proposed a novel feedback regulation mechanism, in which SP1 may transcriptionally activate the PPP1R13L gene expression in the early stage of lung cancer to promote tumor growth, while the accumulation of PPP1R13L drives tumor invasion and metastasis by direct repression of SP1. Thus, this unique feedback loop between PPP1R13L and SP1 may play a vital role in chemical carcinogenesis and serve as a potential intervention target for lung cancer progression attributable to cigarette smoking.

A novel EHD1/CD44/Hippo/SP1 positive feedback loop potentiates stemness and metastasis in lung adenocarcinoma.

There is growing evidence that endocytosis plays a pivotal role in cancer metastasis. In this study, we first identified endocytic and metastasis-associated genes (EMGs) and then investigated the biological functions and mechanisms of EMGs. Cancer stem cells (CSCs)-like characteristics were evaluated by tumour limiting dilution assays, three-dimensional (3D) spheroid cancer models. Microarray analysis was used to identify the pathways significantly regulated by mammalian Eps15 homology domain protein 1 (EHD1) knockdown. Mass spectrometry (MS) was performed to identify EHD1-interacting proteins. The function of EHD1 as a regulator of cluster of differentiation 44 (CD44) endocytic recycling and lysosomal degradation was determined by CD44 biotinylation and recycling assays. EHD1 was identified as a significant EMG. Knockdown of EHD1 suppressed CSCs-like characteristics, epithelial-mesenchymal transition (EMT), migration and invasion of lung adenocarcinoma (LUAD) cells by increasing Hippo kinase cascade activation. Conversely, EHD1 overexpression inhibited the Hippo pathway to promote cancer stemness and metastasis. Notably, utilising MS analysis, the CD44 protein was identified as a potential binding partner of EHD1. Furthermore, EHD1 enhanced CD44 recycling and stability. Indeed, silencing of CD44 or disruption of the EHD1/CD44 interaction enhanced Hippo pathway activity and reduced CSCs-like traits, EMT and metastasis. Interestingly, specificity protein 1 (SP1), a known downstream target gene of the Hippo-TEA-domain family members 1 (TEAD1) pathway, was found to directly bind to the EHD1 promoter region and induce its expression. Among clinical specimens, the EHD1 expression level in LUAD tissues of metastatic patients was higher than that of non-metastatic patients. Our findings emphasise that EHD1 might be a potent anti-metastatic target and present a novel regulatory mechanism by which the EHD1/CD44/Hippo/SP1 positive feedback circuit plays pivotal roles in coupling modules of CSCs-like properties and EMT in LUAD. Targeting this loop may serve as a remedy for patients with advanced metastatic LUAD.

Long Noncoding RNA LINC01006 Facilitates Cell Proliferation, Migration, and Epithelial-Mesenchymal Transition in Lung Adenocarcinoma via Targeting the MicroRNA 129-2-3p/CTNNB1 Axis and Activating Wnt/β-Catenin Signaling Pathway.

Lung adenocarcinoma (LUAD) is a common type of malignancy of lung cancers. Long intergenic noncoding RNAs (lincRNAs) have emerged as crucial regulators of various cancers, including LUAD. LINC01006 is a newly discovered long noncoding RNA (lncRNA) whose function in LUAD remains to be explored. This study is to explore the role of LINC01006 in LUAD. Quantitative real-time PCR (RT-qPCR) analysis and Western blotting were used to determine the expression levels and protein levels, respectively. Functional assays and animal experiments investigated the role of LINC01006 both in vivo and in vitro. Moreover, TOP/FOP assay was performed to detect the activation of the Wnt/β-catenin signaling pathway. The interaction between LINC01006 and microRNA 29-2-3-p (miR-29-2-3-p)/catenin beta 1 (CTNNB1) was explored by RNA binding protein immunoprecipitation (RIP), RNA pulldown, luciferase reporter assays, and rescue experiments. According to the results, LINC01006 was highly expressed in LUAD tissues and cell lines. LINC01006 knockdown significantly suppressed cell proliferative, migratory, and epithelial-mesenchymal transition (EMT) capacities and tumor development. Moreover, LINC01006 enhanced CTNNB1 via sequestering miR-129-2-3p and activated the Wnt/β-catenin pathway in LUAD. Overall, LINC01006 promotes LUAD development via activating the Wnt/β-catenin pathway, implying that LINC01006 might be a promising biomarker for LUAD treatment.

TFAP2A potentiates lung adenocarcinoma metastasis by a novel miR-16 family/TFAP2A/PSG9/TGF-\u03b2 signaling pathway

Transcription factor AP-2α (TFAP2A) was previously regarded as a critical regulator during embryonic development, and its mediation in carcinogenesis has received intensive attention recently. However, its role in lung adenocarcinoma (LUAD) has not been fully elucidated. Here, we tried to investigate TFAP2A expression profiling, clinical significance, biological function and molecular underpinnings in LUAD. We proved LUAD possessed universal TFAP2A high expression, indicating a pervasively poorer prognosis in multiple independent datasets. Then we found TFAP2A was not indispensable for LUAD proliferation, and exogenous overexpression even caused repression. However, we found TFAP2A could potently promote LUAD metastasis possibly by triggering epithelial–mesenchymal transition (EMT) in vitro and in vivo. Furthermore, we demonstrated TFAP2A could transactivate Pregnancy-specific glycoprotein 9 (PSG9) to enhance transforming growth factor β (TGF-β)-triggering EMT in LUAD. Meanwhile, we discovered suppressed post-transcriptional silencing of miR-16 family upon TFAP2A partly contributed to TFAP2A upregulation in LUAD. In clinical specimens, we also validated cancer-regulating effect of miR-16 family/TFAP2A/PSG9 axis, especially for lymph node metastasis of LUAD. In conclusion, we demonstrated that TFAP2A could pivotally facilitate LUAD progression, possibly through a novel pro-metastasis signaling pathway (miR-16 family/TFAP2A/PSG9/ TGF-β).

P1.03-08 RNF43 Ubiquitinates and Degrades Phosphorylated E-Cadherin by c-Src to Facilitate Epithelial-Mesenchymal Transition in Lung Adenocarcinoma

In epithelial cells, tyrosine kinases induce tyrosine phosphorylation and ubiquitination of the E-cadherin complex, which is responsible for the epithelial-mesenchymal transition (EMT). However, the precise mechanisms remain unclear. Protein antibody microarray was applied to identify the potential E3 ligase to downregulate E-cadherin. EMT was determined by morphology, epithelial-mesenchymal markers and aggressive behavior in vivo with the lung adenocarcinoma cell lines and tissues. The molecular biological methods including western blotting, immunoprecipitation, MALDI-Mass, immunohistochemistry, et al were applied to explore the signaling of RNF43-mediated EMT. Protein antibody microarray and E3 ligase profiling revealed that RING finger protein 43 (RNF43) is linked with E-cadherin downregulation within the context of c-Src activation in lung adenocarcinoma tissues. In addition, c-Src-Caspase-8 interaction markedly increased c-Src activity. Activated c-Src phosphorylated E-cadherin at the tyrosine 797 site to initiate RNF43-mediated E-cadherin ubiquitination at lysine 816 and subsequent degradation, thus freeing β-catenin into the nucleus to upregulate Vimentin and RNF43 in lung adenocarcinoma cell. Decreased E-cadherin and increased Vimentin induced EMT phenotype and promoted tumor metastasis. Frizzled 8 (Frz8)-RNF43 induced ubiquitination of phosphorylated E-cadherin was blocked by monoclonal antibody against the cysteine-rich domain (CRD) of Frz8 but not by antibodies against the protease domain (PA) of RNF43. Our data suggest that RNF43 participates in the regulation of EMT in the metastasis of lung adenocarcinoma, through ubiquitination and degradation of phosphorylated E-cadherin by activated c-Src.

RNF43 ubiquitinates and degrades phosphorylated E-cadherin by c-Src to facilitate epithelial-mesenchymal transition in lung adenocarcinoma

BackgroundIn epithelial cells, tyrosine kinases induce tyrosine phosphorylation and ubiquitination of the E-cadherin complex, which is responsible for the epithelial-mesenchymal transition (EMT). However, the precise mechanisms remain unclear.MethodsProtein antibody microarray analysis and E3 ligase profiling were performed to detect the unique E3 ligase underlying E-cadherin downregulation in lung adenocarcinoma tissues. Gene knockdown was performed using viral shRNA. Immunoblotting, immunofluorescence, immunoprecipitation, and xenograft models in vivo were integratively applied to explore RNF43-induced EMT in lung adenocarcinoma cell lines.ResultsProtein antibody microarray analysis and E3 ligase profiling revealed that the RING finger protein 43 (RNF43) was linked to E-cadherin downregulation within the context of c-Src activation in lung adenocarcinoma tissues. In addition, the c-Src-Caspase-8 interaction markedly increased c-Src activity. Activated c-Src phosphorylated E-cadherin at the tyrosine 797 site to initiate RNF43-mediated E-cadherin ubiquitination at lysine 816 and subsequent degradation, thus allowing the nuclear translocation of β-catenin and upregulation of Vimentin and RNF43 expression in lung adenocarcinoma cells. Decreased E-cadherin expression and increased Vimentin expression induced the EMT phenotype and promoted tumor metastasis. The Frizzled 8 (Frz8)-RNF43-induced ubiquitination of phosphorylated E-cadherin was blocked by a monoclonal antibody against the cysteine-rich domain (CRD) of Frz8 but not by antibodies against the protease domain (PA) of RNF43.ConclusionsOur data suggest that RNF43 participates in the regulation of EMT in the metastasis of lung adenocarcinoma through the ubiquitination and degradation of phosphorylated E-cadherin by activated c-Src.

Abstract 4599: PD-1/PD-L1 axis in cancer cells contributes to cellular EMT in lung adenocarcinoma

Abstract Background: Since intrinsic PD-1 receptor functions promote tumor growth was reported, we will investigate the role of PD-L1 in lung adenocarcinoma cells, and their impact on clinical outcome. Materials and methods: Lung adenocarcinoma CL1-5 cells, derived from CL1-0 cells have more invasive ability. We prepared PDL1-overexpression human lung adenocarcinoma cell line, derived from CL1-0 cells (CL1-0-PD1) and from PC14PE6 cells (PC14PE6-PD-L1). We observed the cellular morphology, and invasiveness; epithelial-mesenchymal transition (EMT) markers and regulators were also evaluated. To explore interaction between PD-1 and PD-L1, we treated the CL1-0, CL1-5, CL1-0-PDL1 cells, PC14PE6 cells, and PC14PE6-PD-L1 cells with anti-PD-1 antibody, and then evaluated cellular invasion. We also suppressed PD-1 to test whether PD-1/PDL-1 interaction contributed to the EMT change. Further, we evaluated cellular proliferation and chemosensitivity by MTT assay and colony formation assay. Finally, we correlated PD-L1 expression with clinical outcome in patients’ tumor specimen. Results: CL1-5 cells possessed higher PD-L1 expression than parental CL1-0 cells. CL1-0 cells with PD-L1 overexpression had more expression of EMT regulators and mesenchymal markers. Overexpression of PD-L1 in another lung adenocarcinoma PC14PE cells (PC14PE6-PD-L1 cells) become more aggressive. On the contrary, down-regulation of PD-L1 in CL1-5 cells and PC14-PE6-PD-L1 cells became indolent. Besides through the observation from confocal microscopy, PD-L1 expression was more co-localized with vimentin and slug, individually in CL1-5, CL1-0-PD-L1 and PC14PE6-PD-L1 cells. Therefore, PD-L1 promoted EMT in human lung adenocarcinoma cells. After adding anti-PD-1 antibody in CL1-5, CL1-0, and CL1-0-PDL1 cells, migration and invasion ability were decreased. Similar phenomenon was found when PD-1 antibody treatment in PC14PE6 cells, and PC14PE6-PD-L1 cells. Silencing PD-1 by siRNA also disrupt the cellular aggressivenss in CL1-0-PD-L1 and PC14PE6-PD-L1 cells. These results indicated PD-1/PD-L1 axis regulated cancer cells migration and invasiveness. PD-L1 expression also decreased cellular proliferation and had little influence on chemsensitivity. Finally, we found that higher PD-L1 expression was correlated with lymph node metastasis in clinical specimen. Conclusion: Lung adenocarcinoma cells with higher PD-L1 expression promote EMT via PD-1 receptor. PD-L1 expression lowers proliferation rate, but has little impact on chemosensitivity. Lung cancer patients with high PD-L1 expression in tumor have higher lymph node metastasis. Citation Format: Wen-Pin Su, Li-Chan Chang, Jing-Jou Yan, Wu-Chou Su. PD-1/PD-L1 axis in cancer cells contributes to cellular EMT in lung adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4599.

Glucose-Regulated Protein 78 Signaling Regulates Hypoxia-Induced Epithelial-Mesenchymal Transition in A549 Cells.

Objective: Metastasis and therapeutic resistance are the major determinants of lung cancer progression and high mortality. Epithelial–mesenchymal transition (EMT) plays a key role in the metastasis and therapeutic resistance. Highly expressed glucose-regulated protein 78 (GRP78) is a poor prognostic factor in lung cancer and possibly correlated with EMT. This study aims to examine whether the up-regulation of GRP78 is involved in EMT in lung adenocarcinoma and explore the underlying downstream molecular pathways.Study Design: EMT was assessed by analysis of cell morphology and expression of EMT protein markers in A549 cells under normoxia, hypoxia and silencing GRP78 conditions. The expression levels of Smad2/3, Src, and MAPK (p38, ERK, and JNK) proteins were examined by Western blot analysis under hypoxia and treatments with phosphorylation inhibitors.Results: Under hypoxic conditions, the EMT morphology significantly changed and the GRP78 expression was significantly up-regulated in A549 cells compared with those in normoxia control. The expression and phosphorylation levels of smad2/3, Src, p38, ERK, and JNK were also upregulated. When GRP78 was silenced, EMT was inhibited, and the levels of phospho-smad2/3, phospho-Src, phospho-p38, phospho-ERK, and phospho-JNK were suppressed. When the activation of Smad2/3, Src, p38, ERK, and JNK was inhibited, EMT was also inhibited. The inhibition effect on EMT by these phosphorylation inhibitors was found to be weaker than that of GRP78 knockdown.Conclusions: Hypoxia-induced EMT in A549 cells is regulated by GRP78 signaling pathways. GRP78 promotes EMT by activating Smad2/3 and Src/MAPK pathways. Hence, GRP78 might be a potential target for treatment of lung adenocarcinoma.

MDM2 promotes epithelial-mesenchymal transition through activation of Smad2/3 signaling pathway in lung adenocarcinoma.

BackgroundMouse double minute 2 (MDM2) contributes to cancer metastasis and epithelial–mesenchymal transition (EMT). This study aimed to investigate small mothers against decapentaplegic (Smad) signaling in MDM2-mediated EMT in lung adenocarcinoma (LAC).Materials and methodsExpression patterns of MDM2 in LAC tissues, adjacent tissues, and cell lines (BEAS-2B, PC9, H1975, and A549) were detected. We then overexpressed MDM2 in PC9 cells and knocked it down in H1975 cells. To explore whether MDM2 activates EMT through the Smad2/3 signaling pathway, Smad2 and Smad3 were also silenced by siRNA in H1975 cells. Male BALB/c nude mice were used in in vivo model to validate the effects of MDM2 on LAC cells.ResultsMDM2 was significantly upregulated in LAC tissues compared with adjacent tissues. The expression of MDM2 was relatively higher in PC9 cells and relatively lower in H1975 cells compared with A549 cells. Overexpression of MDM2 significantly increased cell proliferation, migration, and invasion in LAC cells, while inhibiting apoptosis in PC9 cells. On the contrary, silencing of MDM2 significantly inhibited the expression of EMT-related genes N-cadherin and vimentin, while promoting the expression of E-cadherin and β-catenin. In vivo, MDM2 knockdown inhibited tumor growth. In addition, the expression of Smad2/3 was correlated with MDM2 in H1975 cells transfected with Smad2 and Smad3 siRNAs, which inhibited EMT progress.ConclusionMDM2 can activate the Smad2/3 signaling pathway, which promotes the proliferation and EMT progress of LAC cells.

Long noncoding RNA LINC00483/microRNA-144 regulates radiosensitivity and epithelial-mesenchymal transition in lung adenocarcinoma by interacting with HOXA10.

Lung adenocarcinoma (LAD) is the leading cause of cancer death worldwide. Long noncoding RNAs (lncRNAs) have been shown to play an important regulatory role in cancer biology, including that of LAD. The aim of this experiment was to explore the interaction of LINC00483, microRNA-144 (miR-144), and homeobox A10 (HOXA10), and their effects on radio sensitivity and epithelial-mesenchymal transition (EMT) of LAD. Initially, microarray analysis was used to screen out miRNAs and lncRNAs, as well as the differentially expressed genes related to LAD. Following the screening process, the targeting relationship of LINC00483, miR-144, and that of miR-144 and HOXA10 was determined. Following that, the expression of LINC00483, miR-144, messenger RNA (mRNA), as well as protein expression of HOXA10, MMP-2, MMP-9, E-cadherin, vimentin, and N-cadherin that followed in cells was determined. Also, the effect of LINC00483 on cell migration and invasion ability, and cell tumorigenic ability was detected. LINC00483 and HOXA10 were found to be upregulated whereas miR-144 was downregulated in LAD. Silencing of LINC00483 could competitively bind to miR-144, thereby upregulating HOXA10. LINC00483 or HOXA10 silencing led to decreased HOXA10, MMP-2, MMP-9, vimentin, and N-cadherin but elevated miR-144 and E-cadherin. Moreover, after being transfected with silenced LINC00483, the cell proliferation, migration, and invasion were inhibited with enhanced radiosensitivity. Consequently, the data of the study indicates that interference of LINC00483 weakens its competitive binding ability to miR-144, thus reducing HOXA10 expression, and enhancing radiosensitivity in LAD.

TCTP promotes epithelial-mesenchymal transition in lung adenocarcinoma.

BackgroundLung cancer is the most common and lethal malignancy worldwide. TCTP is highly expressed in various cancers including lung cancer. Epithelial–mesenchymal transition (EMT) could increase cancer cell invasion. Whether TCTP’s expression is associated with EMT in lung adenocarcinoma is largely unknown.MethodsSeveral Gene Expression Omnibus datasets were used to analyze the correlation between TCTP expression and overall survival of lung adenocarcinoma patients by Kaplan–Meier survival analysis. Then, 24 surgically removed fresh lung adenocarcinoma tissue samples and paired paracancer tissue samples were used to analyze the correlation between TCTP expression and tumor stage by immunohistochemical analysis. Furthermore, stable cell lines were generated using lentiviral transduction systems to knock down or overexpress TCTP in A549 cells. Cell migration and invasion were measured by scratch and transwell assays, and EMT marker proteins such as α-SMA, ZEB1, and E-cadherin were quantitated by Western blot. The expression levels of miR-200a, miR-141, and miR-429 were determined by real-time quantitative PCR, and their target genes were predicted by an online database miRTarBase. The interaction between TCTP and these genes was analyzed by String database and visualized by Cytoscape.ResultsTCTP was highly expressed in tumor tissues compared to paracancer tissues. The expression of TCTP was associated with shorter overall survival. TCTP knockdown experiment in A549 cells suggested that TCTP knockdown could decrease the migration and invasion of lung cancer cells, and the expression level of ZEB1 and α-SMA, but increase the expression of E-cadherin and p53. Vice versa, overexpression of TCTP could increase the migration and invasion of cancer cells, and the expression level of ZEB1 and α-SMA, but decrease the expression of E-cadherin and p53. Furthermore, we found the expression of miR-200a, miR-141, and miR-429 was associated with TCTP expression.ConclusionTCTP promotes EMT in lung adenocarcinoma, and this effect may be associated with miR-200 family members like miR-200a, miR-141, and miR-429.

MicroRNA-204 targets SOX4 to inhibit metastasis of lung adenocarcinoma.

The dysregulation of microRNAs (miRNAs) has been found in human cancers. In this study, the functions of miR-204 and SOX4 (sex-determining region Y-box 4) and their interaction on lung adenocarcinoma cell metastasis and epithelial-mesenchymal transition (EMT) were investigated. MiR-204 and SOX4 expressions were examined via quantitative Real-time polymerase chain reaction (qRT-PCR) in lung adenocarcinoma. Western blot was used to detect the expressions of SOX4 and EMT markers. The relationship between miR-204 and SOX4 was verified by a dual-luciferase reporter assay. Transwell assay was utilized to explore the functions of miR-204 and SOX4 associated with lung adenocarcinoma metastasis. First, downregulation of miR-204 was examined in lung adenocarcinoma tissues. Moreover, overexpression of miR-204 inhibited metastasis and EMT of lung adenocarcinoma cells. In addition, SOX4 has been shown to be a direct target of miR-204 in lung adenocarcinoma. SOX4 silencing suppressed cell metastasis and EMT in lung adenocarcinoma. And the upregulation of SOX4 impaired the inhibitory effect of miR-204 on lung adenocarcinoma metastasis. MiR-204 inhibited cell metastasis and EMT in lung adenocarcinoma through targeting SOX4.

RUFY3 Predicts Poor Prognosis and Promotes Metastasis through Epithelial-mesenchymal Transition in Lung Adenocarcinoma.

Background: RUFY3 (RUN and FYVE domain-containing protein 3) has been shown to participate in cell migration, membrane transportation, and cellular signaling and is dysregulated in several cancer processes. However, the role of RUFY3 in lung cancer remains unclear. In the present study, we aimed to study the expression of RUFY3 and assess its clinical significance in lung adenocarcinoma.Materials and Methods: We used immunohistochemistry to detect RUFY3 protein expression in human lung adenocarcinoma and adjacent normal lung tissue from 125 patients who underwent surgical resection of the lung cancer. RUFY3 expression was assessed in association with clinicopathological characteristics and clinical prognosis of lung adenocarcinoma patients. The expression of RUFY3 in three different lung adenocarcinoma cell lines and one normal lung epithelial cell (BEAS-2B) was detected by western blot. RNAi technique was used to silence RUFY3. We assessed cell migration by Trans-well assay and wound healing assay.Results: In lung adenocarcinoma tissues, RUFY3 protein was significantly upregulated compared to paired normal lung tissues. High cytoplasmic RUFY3 levels were associated with lymph node metastasis, TNM staging, and survival status. Patients with the highest expression level of RUFY3 had a shorter survival time than patients with the lowest expression. Inhibition of RUFY3 by siRNA inhibited cell migration. Furthermore, silence of RUFY3 lead to up-regulation of E-cadherin, but down-regulation of N-cadherin, Vimentin and Slug.Conclusions: Our study is first to demonstrated that abnormal expression of RUFY3 indicates poor prognosis in lung adenocarcinoma and also indicates that RUFY3 may be related to EMT process. This highlights the potential of RUFY3 as a novel prognostic biomarker for lung adenocarcinoma.

B7-H3 promotes metastasis, proliferation, and epithelial-mesenchymal transition in lung adenocarcinoma.

BackgroundLung adenocarcinoma is the most common pathological type of lung cancer. However, the mechanisms underlying its development are still poorly understood. B7-H3 was discovered as a new member of the B7 costimulatory family.MethodsWe detected the expression status of B7-H3 protein in lung adenocarcinoma tissues, and evaluated the relationship of B7-H3 expression and patients’ prognosis. Then, we silenced its expression in A549 cells by transient siRNA transfection to ascertain the function of B7-H3 in lung adenocarcinoma cells. Western blotting was used to detect the expression of epithelial–mesenchymal transition (EMT) related proteins.ResultsWe found that B7-H3 overexpressed in lung adenocarcinoma. It is correlated with lymph node metastasis, distant metastasis, and disease stage. The Cox regression analysis showed that B7-H3 might serve as an independent prognostic marker of lung adenocarcinoma. We also found that B7-H3 promoted proliferation, invasion and migration of A549 cells in vitro. B7-H3 also could promote EMT progression by regulating EMT-related molecules.ConclusionB7-H3 is a potential target for the treatment of lung adenocarcinoma.

TWIST1 upregulates miR-214 to promote epithelial-to-mesenchymal transition and metastasis in lung adenocarcinoma.

Epithelial-to-mesenchymal transition (EMT) is essential for the progression of non-invasive tumor cells into malignancy and metastasis. We found that miR-214 was increased in lung adenocarcinoma (LAD) and positively associated with metastasis, which was mediated by EMT. However, the mechanism whereby the overexpression of microRNAs(miRNAs), such as miR-214, promote EMT in LAD remains unclear. In this study, we found that TWIST1, an independent prognostic factor for overall survival, was increased in LAD and correlated positively with LAD recurrence and progression. We also found that TWIST1 contributes to the EMT process and metastasis of LAD cells. Most importantly, a positive correlation was found between the expression of miR-214 and TWIST1 in clinical LAD tissue. Additionally, miR-214 expression was decreased and its target gene suppressor of fused homolog (SUFU) was increased in LAD cells in response to the impairment of TWIST1 expression by shRNA. Overall, this study provides the first evidence to show that the high expression of TWIST1 increases the expression of miR-214 to promote the EMT process and metastasis in LAD. These findings contribute to clarify the mechanisms whereby miRNAs regulate the EMT process and implicate a new TWIST1-miR-214 pathway in the control of migration and invasion of LAD.

Epithelial-mesenchymal transition (EMT) signature is inversely associated with T-cell infiltration in non-small cell lung cancer (NSCLC)

Epithelial-mesenchymal transition (EMT) is able to drive metastasis during progression of multiple cancer types, including non-small cell lung cancer (NSCLC). As resistance to immunotherapy has been associated with EMT and immune exclusion in melanoma, it is important to understand alterations to T-cell infiltration and the tumor microenvironment during EMT in lung adenocarcinoma and squamous cell carcinoma. We conducted an integrated analysis of the immune landscape in NSCLCs through EMT scores derived from a previously established 16 gene signature of canonical EMT markers. EMT was associated with exclusion of immune cells critical in the immune response to cancer, with significantly lower infiltration of CD4 T-cells in lung adenocarcinoma and CD4/CD8 T-cells in squamous cell carcinoma. EMT was also associated with increased expression of multiple immunosuppressive cytokines, including IL-10 and TGF-β. Furthermore, overexpression of targetable immune checkpoints, such as CTLA-4 and TIM-3 were associated with EMT in both NSCLCs. An association may exist between immune exclusion and EMT in NSCLC. Further investigation is merited as its mechanism is not completely understood and a better understanding of this association could lead to the development of biomarkers that could accurately predict response to immunotherapy.

Tumor-associated macrophages promote Ezrin phosphorylation-mediated epithelial-mesenchymal transition in lung adenocarcinoma through FUT4/LeY up-regulation.

Tumor-associated macrophages (TAMs) are key components of tumor microenvironment (TME) during tumorigenesis and progression. However, the role of TAMs in lung adenocarcinoma is still unclear. In this study, we aimed to clarify the mechanism underlying the crosstalk between TAMs and epithelial-mesenchymal transition (EMT) of lung adenocarcinoma. Fucosyltransferase IV (FUT4) and its synthetic cancer sugar antigen Lewis Y (LeY) was aberrantly elevated in various solid tumors, it plays critical role in the invasion and metastasis. Here, we found that in lung adenocarcinoma samples, the density of TAMs correlates with E-cadherin level and LeY level. In vitro assays, M2 macrophages promoted FUT4/LeY expression through the transforming growth factor-β1(TGF-β1)/Smad2/3 signaling pathway. FUT4/LeY was indispensable in M2 macrophages-mediated cytoskeletal remodeling and EMT. Furthermore, fucosylation of Ezrin mediated by FUT4/LeY can promote the phosphorylation of Ezrin, which was the critical mechanism of M2 macrophages-induced EMT. In vivo assays confirmed that M2 macrophages promoted EMT through the up-regulation of LeY and phosphorylated Ezrin. Together, our results revealed that TAMs promote Ezrin phosphorylation-mediated EMT in lung adenocarcinoma through FUT4/LeY- mediated fucosylation. Targeting this newly identified signaling may offer new possibilities for immunotherapy in lung adenocarcinoma.

Podocalyxin influences malignant potential by controlling epithelial-mesenchymal transition in lung adenocarcinoma.

Epithelial–mesenchymal transition (EMT) plays an important role in the progression of lung carcinoma. Podocalyxin (PODXL), which belongs to the CD34 family and regulates cell morphology, has been linked to EMT in lung cancer, and PODXL overexpression is associated with poor prognosis in several different classes of cancers. The aim of this study was to clarify the role of PODXL overexpression in EMT in lung cancer, and to determine the prognostic value of PODXL overexpression in tumors from lung cancer patients. The morphology, EMT marker expression, and migration and invasion abilities of engineered A549 PODXL‐knockdown (KD) or PODXL‐overexpression (OE) lung adenocarcinoma cells were examined. PODXL expression levels were assessed by immunohistochemistry in 114 human clinical lung adenocarcinoma specimens and correlated with clinical outcomes. PODXL‐KD cells were epithelial in shape, whereas PODXL‐OE cells displayed mesenchymal morphology. Epithelial markers were upregulated in PODXL‐KD cells and downregulated in PODXL‐OE cells, whereas mesenchymal markers were downregulated in the former and upregulated in the latter. A highly selective inhibitor of phosphatidylinositol 3‐kinase‐Akt signaling attenuated EMT of PODXL‐OE cells, while a transforming growth factor inhibitor did not, suggesting that PODXL induces EMT of lung adenocarcinoma cells via the phosphatidylinositol 3‐kinase pathway. In lung adenocarcinoma clinical specimens, PODXL expression was detected in minimally invasive and invasive adenocarcinoma, but not in non‐invasive adenocarcinoma. Disease free survival and cancer‐specific survival were significantly worse for patients whose tumors overexpressed PODXL. PODXL overexpression induces EMT in lung adenocarcinoma and contributes to tumor progression.

Gli promotes epithelial-mesenchymal transition in human lung adenocarcinomas.

Adenocarcinoma is the most common type of lung cancer. Epithelial-mesenchymal transition (EMT) is required for tumor invasion/metastasis and the components that control this process are potential therapeutic targets. This study we examined the role of Gli in lung adenocarcinoma and whether its activation regulates metastasis through EMT in lung adenocarcinoma. We found that tumors with high Gli expression had significantly lower E-Cadherin expression in two independent cohorts of patients with lung adenocarcinoma that we studied. In vitro up-regulation of SHh resulted in increased cell migration while small molecule inhibitors of Smo or Gli significantly reduced cell mobility both in a wound healing assay and in a 3D cell invasion assay. Inhibition of Gli in vivo decreased tumor growth and induced an increase in E-Cadherin expression. Our results indicate that Gli may be critical for lung adenocarcinoma metastasis and that a novel Gli inhibitor shows promise as a therapeutic agent by preventing cell migration and invasion in vitro and significantly reducing tumor growth and increasing E-Cadherin expression in vivo.