Promoted Non-small Cell Lung Cancer Cell Migration Research Articles

IKKα promotes lung adenocarcinoma growth through ERK signaling activation via DARPP-32-mediated inhibition of PP1 activity

Non-small cell lung cancer (NSCLC) accounts for 80–85% cases of lung cancer cases. Diagnosis at advanced stages is common, after which therapy-refractory disease progression frequently occurs. Therefore, a better understanding of the molecular mechanisms that control NSCLC progression is necessary to develop new therapies. Overexpression of IκB kinase α (IKKα) in NSCLC correlates with poor patient survival. IKKα is an NF-κB-activating kinase that is important in cell survival and differentiation, but its regulation of oncogenic signaling is not well understood. We recently demonstrated that IKKα promotes NSCLC cell migration by physically interacting with dopamine- and cyclic AMP-regulated phosphoprotein, Mr 32000 (DARPP-32), and its truncated splice variant, t-DARPP. Here, we show that IKKα phosphorylates DARPP-32 at threonine 34, resulting in DARPP-32-mediated inhibition of protein phosphatase 1 (PP1), subsequent inhibition of PP1-mediated dephosphorylation of ERK, and activation of ERK signaling to promote lung oncogenesis. Correspondingly, IKKα ablation in human lung adenocarcinoma cells reduced their anchorage-independent growth in soft agar. Mice challenged with IKKα-ablated HCC827 cells exhibited less lung tumor growth than mice orthotopically administered control HCC827 cells. Our findings suggest that IKKα drives NSCLC growth through the activation of ERK signaling via DARPP-32-mediated inhibition of PP1 activity.

Five-hub genes identify potential mechanisms for the progression of asthma to lung cancer.

Previous studies have shown that asthma is a risk factor for lung cancer, while the mechanisms involved remain unclear. We attempted to further explore the association between asthma and non-small cell lung cancer (NSCLC) via bioinformatics analysis. We obtained GSE143303 and GSE18842 from the GEO database. Lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC) groups were downloaded from the TCGA database. Based on the results of differentially expressed genes (DEGs) between asthma and NSCLC, we determined common DEGs by constructing a Venn diagram. Enrichment analysis was used to explore the common pathways of asthma and NSCLC. A protein-protein interaction (PPI) network was constructed to screen hub genes. KM survival analysis was performed to screen prognostic genes in the LUAD and LUSC groups. A Cox model was constructed based on hub genes and validated internally and externally. Tumor Immune Estimation Resource (TIMER) was used to evaluate the association of prognostic gene models with the tumor microenvironment (TME) and immune cell infiltration. Nomogram model was constructed by combining prognostic genes and clinical features. 114 common DEGs were obtained based on asthma and NSCLC data, and enrichment analysis showed that significant enrichment pathways mainly focused on inflammatory pathways. Screening of 5 hub genes as a key prognostic gene model for asthma progression to LUAD, and internal and external validation led to consistent conclusions. In addition, the risk score of the 5 hub genes could be used as a tool to assess the TME and immune cell infiltration. The nomogram model constructed by combining the 5 hub genes with clinical features was accurate for LUAD. Five-hub genes enrich our understanding of the potential mechanisms by which asthma contributes to the increased risk of lung cancer.

Abstract 160: IKKα interacts with DARPP-32 to promote lung adenocarcinoma growth

Abstract Lung cancer is the leading cause of cancer-related death in the U.S. and worldwide. Non-small cell lung cancer (NSCLC) represents 80-85% of all lung cancer diagnoses, most of which present as advanced disease with poor prognoses. Despite existing treatment options, the overall 5-year survival rate of lung cancer patients is about 17%. Many patients are diagnosed with advanced stage disease that frequently progresses after developing resistance to therapy. Therefore, a better understanding of the molecular mechanisms that control NSCLC progression is necessary to develop new therapies to improve the prognoses of patients. We recently demonstrated that dopamine and cyclic AMP-regulated phosphoprotein, Mr 32000 (DARPP-32), and its truncated splice variant, t-DARPP, promote NSCLC growth using functional studies, orthotopic mouse models, and patient-derived specimens. Specifically, we previously reported that DARPP-32 isoforms promote NSCLC cell migration through activation of non-canonical NF-κB2 signaling by establishing a direct physical interaction with inhibitory kappa B kinase-alpha (IKKα). Therefore, we first sought to determine whether IKKα directly phosphorylates DARPP-32. Indeed, we observed that kinase active IKKα protein phosphorylates DARPP-32 protein at the Thr-34 position using in vitro kinase assays. Given that phosphorylated DARPP-32 acts as a potent inhibitor of protein phosphatase 1 (PP1), we assessed PP1 activity upon transient overexpression of IKKα in DARPP-32-overexpressed NSCLC cells. Our findings suggest phosphorylation of DARPP-32 by IKKα results in decreased PP1-mediated phosphatase activity. This DARPP-32-mediated inhibition of PP1 was not observed in NSCLC cells stably overexpressing a form of DARPP-32 that cannot phosphorylated at the Thr-34 residue (via T34A mutation), suggesting IKKα protein phosphorylates DARPP-32 at the Thr-34 position to stimulate DARPP-32-mediated inhibition of PP1 activity. Correspondingly, we have observed increased phosphorylation of ERK protein, a kinase regulated by PP1, upon pharmacological inhibition of PP1 as well as following overexpression of IKKα protein. Ablation of IKKα via lentiviral transduction reduces NSCLC cell growth in soft-agar colony formation assays. Furthermore, using an orthotopic human NSCLC cell line-derived xenograft mouse model, we have shown that depletion of IKKα reduces tumor growth. Taken together, our findings suggest that IKKα contributes to NSCLC growth by interacting with DARPP-32 to stimulate oncogenic kinase activity through the inhibition of PP1 phosphatase activity. Citation Format: Sk. Kayum Alam, Li Wang, Zhu Zhu, Luke H. Hoeppner. IKKα interacts with DARPP-32 to promote lung adenocarcinoma growth [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 160.

Long Non-Coding RNA CAR10 Facilitates Non-Small Cell Lung Cancer Cell Migration and Invasion by Modulating the miR-892a/GJB2 Pathway.

IntroductionNon-coding RNAs, including long non-coding (lnc)RNAs and microRNAs (miRs), play crucial roles in numerous malignant tumors, including non-small cell lung cancer (NSCLC).MethodsThe expression levels of chromatin-associated RNA Intergenic 10 (CAR10), gap junction protein beta 2 (GJB2) and miR-892a in NSCLC were evaluated by reanalyzing three Gene Expression Omnibus (GEO) datasets, and performing reverse transcription-quantitative PCR, immunohistochemistry staining and Western blot analysis, accordingly. Functionally, Transwell and Matrigel assays were performed to measure changes in the migration and invasion abilities of the A549 and H1299 cell lines. The targeted binding effects between CAR10 and miR-892a, as well as between miR-892a and GJB2 were confirmed by conducting dual-luciferase reporter and RNA pull-down assays, respectively.ResultsThe present study demonstrated that CAR10 was upregulated in patients with NSCLC, which was also associated with a poor prognosis. Functionally, CAR10 was confirmed to be oncogenic and promoted NSCLC cell migration and invasion, using overexpression and knockdown Transwell assays. Furthermore, GJB2 expression was revealed to be upregulated and was positively correlated with CAR10 expression in NSCLC. A further mechanistic study revealed that GJB2 was a downstream target of CAR10, which induced the migration and invasive potential of the A549 and H1299 cell lines. More specifically, miR-892a was found to serve as a bridge between CAR10 and GJB2, via similar miRNA response elements. The RNA pull-down and luciferase assays indicated that miR-892a directly binds both CAR10 and GJB2.ConclusionCAR10 promoted NSCLC cell migration and invasion by upregulating GJB2 and sponging miR-892a. These findings illustrated that the CAR10/miR-892a/GJB2 axis may be a novel molecular target for the treatment of NSCLC.

TPX2 Promotes Metastasis and Serves as a Marker of Poor Prognosis in Non-Small Cell Lung Cancer

BackgroundMetastasis contributes to the high mortality rate of non-small cell lung cancer (NSCLC), and gaining a better understanding of its metastatic mechanisms would aid in initiating effective clinical treatment.Material/MethodIn this study, bioinformatics analyses of the GEO database and TCGA-LUAD were first used to identify the key node gene regulating NSCLC malignant progression. Further in vitro experiments, including wound healing assay, invasion assay, Western blot assay, and luciferase report assay, were used to clarify the functions and mechanism of TPX2 in NSCLC.ResultsResults of the TCGA analysis showed that TPX2 was significantly positively correlated with tumor metastasis and growth and the clinical stage of NSCLC. In addition, high levels of TPX2 significantly indicated a poor survival rate. In vitro experimental results also revealed that the upregulation of TPX2 significantly promoted NSCLC cell migration and invasion and could affect cell replasticity. Further results indicated that TPX2 significantly activated the epithelial-mesenchymal transition process and promoted the expression and activities of matrix metalloproteinase (MMP)2 and MMP9.ConclusionsThis study demonstrated that TPX2 promotes the metastasis and malignant progression of NSCLC and could thus serve as a marker of poor prognosis in NSCLC.

LncRNA FEZF1-AS1 promotes non-small lung cancer cell migration and invasion through the up-regulation of NOTCH1 by serving as a sponge of miR-34a

BackgroundThe involvement of lncRNA FEZF1-AS1 has been analyzed in many types of cancers, while its roles in non-small cell lung cancer (NSCLC) remains unclear. We then explored the role of FEZF1-AS1 in NSCLC.MethodsqPCR and western blot were performed to measure gene expression. FEZF1-AS1, miR-34a, and NOTCH-1 were overexpressed to analyze the relationship between them. Transwell assays were performed to analyze the effects of transfections on cell invasion and migration.ResultsFEZF1-AS1 was up-regulated in NSCLC patients. Increased expression levels of FEZF1-AS1 were observed with the increase in clinical stages. Bioinformatics analysis showed that miR-34a can bind with FEZF1-AS1. In NSCLC tissues, NOTCH-1 and FEZF1-AS1 were positively correlated. In NSCLC cells, over-expression of FEZF1-AS1 resulted in up-regulated expressions of NOTCH-1, while miR-34a over-expression mediated down-regulated expressions of NOTCH-1. In addition, FEZF1-AS1 and miR-34a did not alter each other, while bioinformatics analysis showed that miR-34a can bind FEZF1-AS1. Analysis of cell migration and invasion showed increased cell invasion and migration rates after FEZF1-AS1 and NOTCH-1 over-expression. MiR-34a played the opposite role and reduced the effects of FEZF1-AS1 over-expression.ConclusionsFEZF1-AS1 promoted NSCLC cell migration and invasion through the up-regulation of NOTCH1 by serving as a sponge of miR-34a.

Proteoglycan serglycin promotes non-small cell lung cancer cell migration through the interaction of its glycosaminoglycans with CD44

BackgroundSerglycin (SRGN), previously recognized as an intracellular proteoglycan involved in the storage processes of secretory granules, has recently been shown to be upregulated in several solid tumors. We have previously shown that SRGN in non-small cell lung cancer (NSCLC) promotes malignant phenotypes in a CD44-dependent manner and increased expression of SRGN predicts poor prognosis of primary lung adenocarcinomas. However, the underlying mechanism remains to be defined.MethodsOverexpression, knockdown and knockout approaches were performed to assess the role of SRGN in cell motility using wound healing and Boyden chamber migration assays. SRGN devoid of glycosaminoglycan (GAG) modification was produced by site-directed mutagenesis or chondroitinase treatment. Liquid chromatography/tandem mass spectrometry was applied for quantitative analysis of the disaccharide compositions and sulfation extent of SRGN GAGs. Western blot and co-immunoprecipitation analyses were performed to determine the expression and interaction of proteins of interest. Actin cytoskeleton organization was monitored by immunofluorescence staining.ResultsSRGN expressed by NSCLC cells is readily secreted to the extracellular matrix in a heavily glycosylated form attached with mainly chondroitin sulfate (CS)-GAG chains, and to a lesser extent with heparin sulfate (HS). The CS-GAG moiety serves as the structural motif for SRGN binding to tumor cell surface CD44 and promotes cell migration. SRGN devoid of CS-GAG modification fails to interact with CD44 and has lost the ability to promote cell migration. SRGN/CD44 interaction promotes focal adhesion turnover via Src-mediated paxillin phosphorylation and disassembly of paxillin/FAK adhesion complex, facilitating cell migration. In support, depletion of Src activity or removal of CS-GAGs efficiently blocks SRGN-mediated Src activation and cell migration. SRGN also promotes cell migration via inducing cytoskeleton reorganization mediated through RAC1 and CDC42 activation accompanied with increased lamellipodia and filopodia formation.ConclusionsProteoglycan SRGN promotes NSCLC cell migration via the binding of its GAG motif to CD44. SRGN/CD44 interaction induces Rho-family GTPase-mediated cytoskeleton reorganization and facilitates Src-mediated focal adhesion turnover, leading to increased cell migration. These findings suggest that targeting specific glycans in tumor microenvironment that serve as ligands for oncogenic pathways may be a potential strategy for cancer therapy.

FAM83A signaling induces epithelial-mesenchymal transition by the PI3K/AKT/Snail pathway in NSCLC.

Family with sequence similarity 83, member A (FAM83A), as a potential tumor promoter, was reported to contribute to the progression of several malignant tumors. However, the significance of FAM83A in invasion and metastasis of non-small cell lung cancer (NSCLC) remains largely unknown. In this study, we found that FAM83A expression was significantly increased in NSCLC tissues. High expression of FAM83A was positively associated with tumor metastasis and poor survival of NSCLC patients. Functional experiments revealed that FAM83A knockdown could suppress NSCLC cell migration and invasion both in vivo and in vitro. While opposite results were observed in FAM83A-transfected cells. Mechanically, we found that FAM83A promoted NSCLC cell migration and invasion by inducing epithelial-mesenchymal transition (EMT) via PI3K/ATK/Snail signaling. Rescue experiment demonstrated that inhibition of either AKT or Snail could partially counteract the promoting effect of FAM83A overexpression in NSCLC metastasis. Taken together, our findings are the first time to demonstrate that increased expression of FAM83A in NSCLC was correlated with EMT and tumor metastasis, which may provide a novel therapeutic target in NSCLC treatment.

LncRNA AWPPH participates in the metastasis of non-small cell lung cancer by upregulating TGF-β1 expression.

Long non-coding RNA (lncRNA) AWPPH is a characterized oncogenic lncRNA in hepatocellular carcinoma and bladder cancer. The aim of the present study was to investigate the potential involvement of AWPPH in non-small cell lung cancer (NSCLC). Expression of AWPPH in lung biopsy tissues and serum of both healthy controls and patients with NSCLC with different tumor sizes, and with and without distant tumor metastasis was detected by reverse transcription-quantitative PCR. AWPPH expression vector was constructed and transfected into cells of human NSCLC cell lines. Expression of TGF-β1 was detected by western blot analysis. Cell migration and invasion were detected by Transwell migration and invasion assay. It was observed that AWPPH was significantly upregulated in patients with NSCLC, while AWPPH expression level did not increase with the increase of tumor size. In contrast, AWPPH expression levels were significantly higher in patients with distant metastasis than in patients without tumor distant metastasis. AWPPH overexpression promoted TGF-β1 expression in NSCLC cells, while TGF-β1 treatment showed no significant effects on AWPPH expression. AWPPH overexpression promoted NSCLC cell migration and invasion, while TGF-β signaling inhibition reduced this enhancing effect. Therefore, AWPPH may promote the metastasis, but not the growth of NSCLC by upregulating TGF-β1 expression.

Abstract 873: Molecular mechanisms of non-small cell lung cancer growth and drug resistance

Abstract Lung cancer is the deadliest and most frequently diagnosed type of tumor worldwide, with 1.6 million deaths reported annually. Non-small cell lung cancer (NSCLC) represents 85% of all lung cancer cases and carries a poor 5-year survival rate below 15%. Prognoses remain dismal due to the large number of patients diagnosed with advanced stage disease and the development of resistance to current therapies. A better understanding of acquired drug resistance will help to circumvent the progression of lung cancer and make significant strides in improving NSCLC patient treatment. Our recent work demonstrates that dopamine and cAMP-regulated phosphoprotein, Mr 32000 (DARPP-32) and its amino-terminally truncated splice variant (t-DARPP) promote lung tumor growth in orthotopic mouse models. IHC staining of 62 human lung adenocarcinoma tissues showed that t-DARPP expression is elevated with increasing tumor (T) staging score, which represents the size of the primary tumor and whether it has grown into nearby areas, as a metric of tumor progression and growth. Correspondingly, a computational biology analysis of 513 lung adenocarcinoma patients revealed upregulation of t-DARPP isoform expression correlates with advanced T stage and is associated with poor overall survival. We identified a novel physical interaction between DARPP-32 and inhibitory kappa B kinase-α (IKKα) that promotes NSCLC cell migration through activation of non-canonical NF-κB2 signaling. It has been shown that DARPP-32 overexpression inhibits gefitinib-induced apoptosis in gastric cancer and t-DARPP contributes to the trastuzumab resistance phenotype in breast cancer. Our recent findings suggest DARPP-32 and t-DARPP overexpression in NSCLC promotes resistance to specific molecular targeted inhibitors by enabling tumor cells to evade apoptosis via Akt- and Erk-dependent cell survival mechanisms. Current ongoing studies are focused on manipulating expression of DARPP-32 isoforms in lung tumor cells to prevent resistance to targeted therapies in NSCLC patients. Citation Format: SK Kayum Alam, Matteo Astone, Ping Liu, Li Wang, Abbygail M. Coyle, Erin N. Dankert, Dane K. Hoffman, Stephanie R. Hall, Wei Zhang, Rui Kuang, Anja C. Roden, Aaron S. Mansfield, Luke H. Hoeppner. Molecular mechanisms of non-small cell lung cancer growth and drug resistance [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 873.

LncRNA TP73-AS1 is upregulated in non-small cell lung cancer and predicts poor survival

The present study was carried out to investigate the role of lncRNA TP73-AS1 in non-small cell lung cancer (NSCLC). We found that TP73-AS1 was upregulated in tumor tissues than in non-tumor tissues of NSCLC patients, and high expression levels of TP73-AS1 predicted poor survival. MiR-21 was also upregulated in tumor tissues and positively correlated with TP73-AS1. TP73-AS1 overexpression led to miR-21 upregulation, while miR-21 overexpression failed to affect TP73-AS1. TP73-AS1 and miR-21 overexpression caused the accelerated invasion and migration of NSCLC cells. However, TP73-AS1 overexpression failed to affect cell proliferation. Therefore, TP73-AS1 may upregulate miR-21 to promote NSCLC cell migration and invasion.

SUMO1P3 is associated clinical progression and facilitates cell migration and invasion through regulating miR-136 in non-small cell lung cancer

Long non-coding RNA small ubiquitin-like modifier 1 pseudogene 3 (SUMO1P3) is located on chromosome 1q23.2, and has been suggested to serve as oncogenic lncRNA in many kinds of human malignancy. The role of SUMO1P3 in non-small cell lung cancer (NSCLC) was still unknown. In our study, we analyzed The Cancer Genome Atlas (TCGA) database, and observed SUMO1P3 expression was increased in both lung squamous cell carcinoma and lung adenocarcinoma. Then, we confirmed that SUMO1P3 expression was significantly increased in NSCLC cancer tissues and cell lines. Meanwhile, the expression levels of SUMO1P3 expression in metastatic lymph node specimens were strikingly elevated in comparison to primary NSCLC tissue specimens. Then, we found high SUMO1P3 expression was correlated with late clinical stage, lymph node metastasis, distant metastasis and poor differentiated degree. In the survival analysis of TCGA, we observed that SUMO1P3 expression had no association with overall survival and disease free survival in NSCLC patients. There was a statistically negative correlation between SUMO1P3 expression and miR-136 expression in NSCLC tissues. Moreover, miR-136 directly bound to SUMO1P3, and SUMO1P3 negatively regulated miR-136 expression in NSCLC cells. Furthermore, SUMO1P3 promoted NSCLC cell migration and invasion via regulating miR-136. In conclusion, SUMO1P3 functions as metastasis-associated lncRNA in NSCLC.

Long noncoding RNA PCAT6 functions as an oncogene by binding to EZH2 and suppressing LATS2 in non-small-cell lung cancer.

BackgroundNSCLC (non-small-cell lung cancer) is the leading cause of cancer-related mortality worldwide. Both epigenetic and genetic changes contribute to the initiation, development and metastasis of NSCLC. Recently, accumulating data have begun to support the notion that long noncoding RNAs (lncRNAs) function as new crucial regulators of diverse biological processes, including proliferation, apoptosis and metastasis, and play crucial roles in tumorigenesis. Nevertheless, further study is warranted to comprehensively determine lncRNAs' functions and potential mechanism.MethodsIn this study, we performed a comprehensive analysis of the lncRNA expression profile of NSCLC using data from TCGA and Gene Expression Omnibus (GEO). PCAT6 expression level in a cohort of 60 pairs of NSCLC tissues using quantitative real-time PCR (qRT-PCR). Additionally, Loss-of-function assays and gain-of-function assays were used to assess the role of PCAT6 in promoting NSCLC progression. Tumor formation assay in a nude mouse model was performed to verity the role of PCAT6 in NSCLC in vivo. Meanwhile, RIP, ChIP, resue experiment and western blot assays were used to highlights the potential molecular mechanism of PCAT6 in NSCLC.FindingsWe identified that an oncogene, PCAT6, was upregulated in NSCLC, and this upregulation was verified in a cohort of 60 pairs of NSCLC tissues. Additionally, the expression level of PCAT6 was correlated with tumor size (P = .036), lymph node metastasis (P = .029) and TNM stage (P = .038). Loss-of-function and gain-of-function assays were used to assess the role of PCAT6 in promoting NSCLC progression. The results revealed that PCAT6 knockdown mitigated NSCLC cell growth by inducing G1-phase cell cycle arrest and apoptosis in vitro and in vivo. Whereas, PCAT6 overexpression could promoted tumor cell growth. Meanwhile, PCAT6 additionally promoted NSCLC cell migration and invasion. Furthermore, mechanistic investigation demonstrated that the oncogenic activity of PCAT6 is partially attributable to its repression of LATS2 via association with the epigenetic repressor EZH2 (Enhancer of zeste homolog 2). Overall, our study highlights the essential role of PCAT6 in NSCLC, suggesting that PCAT6 might be a potent therapeutic target for patients with NSCLC.

LncRA ANCR Inhibits Non-Small Cell Lung Cancer Cell Migration and Invasion by Inactivating TGF-β Pathway.

BackgroundlncRNA ANCR is proved to be a tumor suppressor gene only in colorectal cancer and breast cancer. Our study aimed to explore the possible involvement of ACNR in non-small cell lung cancer (NSCLC).Material/MethodsIn this study, we first detected the expression of ACNR in lung biopsies and plasma of both NSCLC patients and healthy controls. The diagnostic value of ANCR for NSCLC was analyzed by ROC curve analysis. Follow-up data of NSCLC patients was analyzed and the prognostic value of ANCR was analyzed by survival curve analysis. ANCR expression vector was transfected into cells of human NSCLC cell lines, and the effects on cell migration and invasion were explored by Transwell migration and invasion assays, respectively. TGF-β1 expression after ANCR overexpression was detected by Western blot analysis.ResultsANCR was significantly downregulated in NSCLC patients compared with healthy controls in lung biopsies and plasma. Downregulated expression of ANCR distinguishes NSCLC patients from healthy controls and low NSCLC expression level indicates shorter postoperative survival time of NSCLC patients. ANCR overexpression inhibited NSCLC cell migration and invasion and downregulated TGF-β1 expression, while TGF-β1 treatment showed no significant effects on ANCR expression but promoted NSCLC cell migration and invasion. In addition, TGF-β1 treatment also attenuated the inhibitory effects of ANCR overexpression on NSCLC cell migration and invasion.ConclusionsANCR can inhibit NSCLC cell migration and invasion by downregulating TGF-β1 expression.

Abstract 5161: DARPP-32 and t-DARPP promote non-small cell lung cancer growth through regulation of IKKα-dependent cell migration and Akt/Erk-mediated cell survival

Abstract Lung cancer is the leading cause of cancer-related death worldwide. In this study, we demonstrate that elevated expression of dopamine and cyclic adenosine monophosphate-regulated phosphoprotein, Mr 32000 (DARPP-32) and its truncated splice variant t-DARPP promotes lung tumor growth, while abrogation of DARPP-32 expression in human non-small cell lung cancer (NSCLC) cells reduces tumor growth in orthotopic mouse models. We observe a novel physical interaction between DARPP-32 and inhibitory kappa B kinase-α (IKKα) that promotes NSCLC cell migration through non-canonical nuclear factor kappa-light-chain-enhancer of activated B cells 2 (NF-κB2) signaling. Bioinformatics analysis of 513 lung adenocarcinoma patients reveals elevated t-DARPP isoform expression is associated with poor overall survival. Histopathological investigation of 62 human lung adenocarcinoma tissues also showed that t-DARPP expression is elevated with increasing tumor (T) stage. Our data suggest that DARPP-32 is a negative prognostic marker associated with increasing stages of NSCLC and may represent a novel therapeutic target. Citation Format: Sk. Kayum Alam, Matteo Astone, Ping Liu, Stephanie R. Hall, Abbygail M. Coyle, Erin N. Dankert, Dane K. Hoffman, Wei Zhang, Rui Kuang, Anja C. Roden, Aaron S. Mansfield, Luke H. Hoeppner. DARPP-32 and t-DARPP promote non-small cell lung cancer growth through regulation of IKKα-dependent cell migration and Akt/Erk-mediated cell survival [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5161.

DARPP-32 and t-DARPP promote non-small cell lung cancer growth through regulation of IKK\u03b1-dependent cell migration

Lung cancer is the leading cause of cancer-related death worldwide. Here we demonstrate that elevated expression of dopamine and cyclic adenosine monophosphate-regulated phosphoprotein, Mr 32000 (DARPP-32), and its truncated splice variant t-DARPP promote lung tumor growth, while abrogation of DARPP-32 expression in human non-small-cell lung cancer (NSCLC) cells reduces tumor growth in orthotopic mouse models. We observe a physical interaction between DARPP-32 and inhibitory kappa B kinase-α (IKKα) that promotes NSCLC cell migration through non-canonical nuclear factor kappa-light-chain-enhancer of activated B cells 2 (NF-κB2) signaling. Bioinformatics analysis of 513 lung adenocarcinoma patients reveals that elevated t-DARPP isoform expression is associated with poor overall survival. Histopathological investigation of 62 human lung adenocarcinoma tissues also shows that t-DARPP expression is elevated with increasing tumor (T) stage. Our data suggest that DARPP-32 isoforms serve as a negative prognostic marker associated with increasing stages of NSCLC and may represent a novel therapeutic target.

MiR-25 enhances cell migration and invasion in non-small-cell lung cancer cells via ERK signaling pathway by inhibiting KLF4.

In recent years, microRNAs (miRNAs/miRs) have gained increasing interest in cancer research. Increasing evidences demonstrated that miRNAs are important for tumor early detection and prognosis. The present study aimed to explore the function of miR-25 in non-small-cell lung cancer (NSCLC) and its underlying mechanisms. The expression levels of miR-25 and Krüppel-like factor 4 (KLF4) were assessed in 31 pairs of tissue from patients with NSCLC. In addition, the biological roles of miR-25 in NSCLC were analyzed via a cell wound healing assay, Transwell invasion and migration assays. Target genes of miR-25 were predicted using TargetScan and verified via a dual luciferase activity assay, western blotting and reverse transcription-quantitative polymerase chain reaction. The downstream signaling pathway was confirmed by western blot analysis. In the present study, miR-25 was overexpressed in 31 NSCLC samples compared with in corresponding normal tissues. Overexpression of miR-25 using miR-25 mimics markedly promoted NSCLC cell migration and invasion, while inhibition of miR-25 exerted the opposite effect. KLF4 was suggested to be a novel target gene of miR-25 in NSCLC cells. Knockdown of KLF4 promoted the migration and invasion of NSCLC cells, whereas rescue of KLF4 expression reduced cell motion ability in miR-25-overexpressing NSCLC cells. Furthermore, it was demonstrated that miR-25 activated the extracellular signal-regulated kinase (ERK) signaling pathway, which eventually led to increased vimentin, matrix metalloproteinase 11 and N-cadherin levels, and the downregulation of E-cadherin expression by inhibiting the expression of KLF4. In conclusion, miR-25 was demonstrated to activate the ERK signaling pathway by directly targeting KLF4, promoting cell migration and invasion. The findings of the present study indicated that miR-25 or KLF4 may serve as a therapeutic target for the treatment of NSCLC.

MiR-224 enhances invasion and metastasis by targeting HOXD10 in non-small cell lung cancer cells

Increasing number of studies have indicated aberrant microRNA (miRNA) expression could affect normal biological progress in non-small cell lung cancer (NSCLC) cells. This study was performed to evaluate the biologic functions of microRNA-224 (miR-224) in NSCLC. Real-time PCR was performed to evaluate the expression of miR-224 and Homeobox D10 (HOXD10) in NSCLC cell lines and tissues. Transwell assays were performed to investigate the function of miR-224 on NSCLC cell migration and invasion. Moreover, western blotting and luciferase assays were used to investigate HOXD10 as miR-224 downstream targets. miR-224 is increased in NSCLC metastatic tissues and cell lines. Increased miR-224 expression promoted NSCLC cell migration and invasion, while low miR-224 expression suppressed NSCLC cell migration and invasion. Furthermore, HOXD10 was targeted directly by miR-224 in NSCLC cells. Moreover, we found that HOXD10 was a functional target and influenced tumour-inductive functions of miR-224 on progression of NSCLC. These findings suggest that miR-224 may be used in the treatment of NSCLC. Targeting this novel strategy, miR-224/HOXD10 axis may be helpful as promising biomarker and therapeutic method to control NSCLC cell metastasis.

The membrane bile acid receptor TGR5 drives cell growth and migration via activation of the JAK2/STAT3 signaling pathway in non-small cell lung cancer

Mounting evidence suggests that an emerging G protein-coupled receptor, TGR5, plays a crucial role ranging from metabolic diseases to cancers. However, the biological functions of TGR5 in non-small cell lung cancer (NSCLC) remain elusive. We found that TGR5 was aberrantly expressed in NSCLC and positively correlated with an advanced clinical stage in NSCLC patients. We further discovered that TGR5 knockdown prevented JAK2 and STAT3 phosphorylation and repressed the expression of STAT3 target genes, thus inhibiting cell proliferation, migration and invasion in NSCLC. Moreover, the promotive effects of TGR5 were significantly reversed by a JAK2 inhibitor or STAT3 knockdown. Additionally, we demonstrated a positive correlation between TGR5 and p-STAT3 expression in NSCLC tissue samples. Patients with both high TGR5 and p-STAT3 expression had the worst prognosis. In addition, the serum levels of deoxycholic acid (DCA), ursodeoxycholic acid (UDCA) and chenodeoxycholic acid (CDCA) in NSCLC patients were much higher than those in the healthy controls and the patients with higher serum DCA levels had stronger TGR5 expression simultaneously. Moreover, DCA markedly promoted NSCLC cell migration and invasion through a TGR5-dependent way. Taken together, these results indicate that TGR5 drives cell growth and migration through JAK2/STAT3 signaling pathway in NSCLC.

Retraction Note: The microRNA-1246 promotes metastasis in non-small cell lung cancer by targeting cytoplasmic polyadenylation element-binding protein

The microRNAs present a class of non-coding RNAs which are usually implicated in tumor biology. Recent report has unraveled that a novel member of microRNA family called miR-1246. However, the functional role and molecular mechanisms of miR-1246 in non-small cell lung cancer (NSCLC) is still elusive. Using RT-PCR, luciferase reporter, mRNA microarrays, invasion and migration assays, we investigated the potential role of miR-1246 in the pathogenesis of NSCLC. In this study, we showed that miR-1246 markedly promoted NSCLC cell migration and invasion. Meanwhile, we found that cytoplasmic polyadenylation element binding protein 4 (CPEB4) might be involved and serve as a direct target of miR-1246 in NSCLC. CPEB4 knockdown substantially enhanced NSCLC migration and invasion resembling the effect of miR-1246 in NSCLC. CPEB4 is also frequently downregulated in NSCLC and decreased CPEB4 expression correlated with poor survival. These results suggested that the miR-1246 may promote cell metastasis by targeting CPEB4. Meanwhile, the level of CPEB4 could be used as a potential marker in NSCLC patients. Our findings unraveled novel functions of miR-1246 in lung cancer cells and shed light on NSCLC prognosis.