Knockdown of MRPL35 promotes cell apoptosis and inhibits cell proliferation in non-small-cell lung cancer.

BACKGROUND: Non-small cell lung cancer (NSCLC) is a major pathological type of lung cancer. However, its pathogenesis remains largely unclear. MRPL35 is a regulatory subunit of the mitoribosome, which can regulate the assembly of cytochrome c oxidases and plays an important role in the occurrence of NSCLC. METHODS: The expression of MRPL35 in NSCLC was detected by tissue microarray and immunohistochemistry. H1299 cells were infected with lentivirus to knockdown MRPL35, and the cells were subjected to crystal violet staining to assess the results of colony formation assays. A549 cells were infected by lentiviral particles-expressing shMRPL35 or shControl, and then subcutaneously injected into nude mice. Tumorigenesis in mice was detected by in vivo imaging. The potential pathway of MRPL35 in NSCLC was assessed by Western blotting. RESULTS: MRPL35 was over-expressed in NSCLC tissue compared to para-cancerous and normal tissues. Knockdown of MRPL35 suppressed cell proliferation and decreased NSCLC progression both in vitro and in vivo. The possible molecular mechanisms were also clarified, which indicated that MRPL35 could be involved in cell apoptosis and proliferation by modulating the expression levels of CDK1, BIRC5, CHEK1, STMN1 and MCM2. Knockdown of MRPL35 activated p53 signaling pathway and inhibited cell cycle regulation. CONCLUSIONS: The oncogenic role of MRPL35 in NSCLC was potentially mediated through the cell cycle regulatory genes such as BIRC5, STMN1, CDK1, CHEK1 and MCM2, as well as activation of P53 signaling pathway.

Identification of Two Subsets of Subcompartment A1 Associated with High Transcriptional Activity and Frequent Loop Extrusion.

Three-dimensional genome organization has been increasingly recognized as an important determinant of the precise regulation of gene expression in mammalian cells, yet the relationship between gene transcriptional activity and spatial subcompartment positioning is still not fully comprehended. Here, we first utilized genome-wide Hi-C data to infer eight types of subcompartment (labeled A1, A2, A3, A4, B1, B2, B3, and B4) in mouse embryonic stem cells and four primary differentiated cell types, including thymocytes, macrophages, neural progenitor cells, and cortical neurons. Transitions of subcompartments may confer gene expression changes in different cell types. Intriguingly, we identified two subsets of subcompartments defined by higher gene density and characterized by strongly looped contact domains, named common A1 and variable A1, respectively. We revealed that common A1, which includes highly expressed genes and abundant housekeeping genes, shows a ~2-fold higher gene density than the variable A1, where cell type-specific genes are significantly enriched. Thus, our study supports a model in which both types of genomic loci with constitutive and regulatory high transcriptional activity can drive the subcompartment A1 formation. Special chromatin subcompartment arrangement and intradomain interactions may, in turn, contribute to maintaining proper levels of gene expression, especially for regulatory non-housekeeping genes.

MPZL1 Promotes Lung Adenocarcinoma Progression by Enhancing Tumor Proliferation, Invasion, Migration, and Suppressing Immune Function via Transforming Growth Factor-ß1.

Lung cancer (LC) is the leading cause of death worldwide, and lung adenocarcinoma (LUAD) is the most common form of LC. The abnormally high expression of myelin protein zero-like 1 (MPZL1) promotes the malignant progression of various tumors. However, there is no relevant report on the functional role of MPZL1 in LUAU. In this study, we applied Illumina sequencing to screen differentially expressed genes. Subsequently, MPZL1 was selected as hub gene for quantitative real-time polymerase chain reaction (qRT-PCR) and CCK8 assay. The expression level of MPZL1 was analyzed by immunohistochemistry, immunofluorescence, western blot, and qRT-PCR. After silencing or overexpressing MPZL1, CCK8, EDU, clone formation, scratch healing, invasion, and nude mouse tumor-bearing experiments were performed to detect the abilities of cell proliferation, migration, invasion, and tumorigenicity. Moreover, qRT-PCR, western blot, coimmunoprecipitation, and scratch healing assays were conducted to explore the transcriptional regulatory factors of MPZL1. Finally, the relationship between MPZL1 and immunotherapy was explored through public databases and validated in vivo. The results show that a total of 196 high-expressed genes and 496 low-expressed genes were screened. Differential genes are mainly enriched in cell proliferation and division, protein binding, and other pathways and functions. MPZL1 was selected as the hub gene and upregulated in LUAD tissues and cells. Silencing MPZL1 inhibited the cell proliferation and cloning formation, and the growth of tumor. Conversely, overexpression of MPZL1 has the opposite effect. In addition, MPZL1 combines with the transforming growth factor-ß1 to promote the progress of LUAD. Finally, we found that high expression of MPZL1 is negatively correlated with infiltration of CD8+ cells and may lead to immunotherapy resistance. In summary, this study revealed a new mechanism by which MPZL1 promotes LUAD progression by enhancing tumor proliferation, invasion, migration, and suppressing immune function.

A phase I study of FCN-411, a pan-HER inhibitor, in EGFR-mutated advanced NSCLC after progression on EGFR tyrosine kinase inhibitors.

BACKGROUND: There are no approved epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) for EGFR-mutated non-small cell lung cancer (NSCLC) without EGFR T790M mutation after progression on first- or second-generation EGFR-TKIs. METHODS: We conducted this phase I, open-label, multicenter, dose-escalation/dose-expansion study to evaluate the safety, tolerability, antitumor activity, and pharmacokinetics of FCN-411, a TKI targeting EGFR, HER2, and HER4, in patients with EGFR-mutated advanced NSCLC whose disease had progressed during treatment of EGFR-TKIs. Adult patients with stage IIIB-IV NSCLC harboring EGFR mutations (exon 18/19/20/21) who had progressed on prior EGFR-TKIs were enrolled. In the dose-escalation phase, patients received 4 mg, 8 mg, 12 mg, and 16 mg FCN-411 once daily until the maximum tolerated dose (MTD). In the dose-expansion phase, patients received FCN-411 at the recommended phase II dose (RP2D) continuously in 21-day cycles. The primary endpoints were safety, tolerability, MTD, and RP2D. RESULTS: From July 23, 2018 to September 29, 2020, 77 patients were enrolled, including 30 with EGFR T790M mutation in tumor tissues. The cut-off date was February 1, 2021. No dose-limiting toxicities were observed. The most common grade ≥ 3 treatment-emergent adverse events among all patients were diarrhea (8; 10.4%) and dermatitis acneiform (7; 9.1%). Ten of 67 evaluable patients achieved confirmed partial response, with an objective response rate (ORR) of 14.9% (95% confidence interval [CI], 8.3-24.0); the ORR was 33.3%, 14.0%, 0, and 25.0% at 4 mg, 8 mg, 12 mg, and 16 mg, respectively. Besides, the ORR in patients without and with EGFR T790M mutation was 20.5% and 7.4%, respectively. Moreover, 39 patients achieved stable disease across all doses, and the disease control rate was 73.1% (95% CI, 60.9-83.2). Median progression-free survival was 4.1 (95% CI, 2.9-5.3) months. Median duration of response and overall survival have not been reached. CONCLUSIONS: FCN-411 was well tolerated and demonstrated preliminary antitumor activity in patients with EGFR-mutated NSCLC after progression on EGFR-TKIs, especially in those without EGFR T790M mutation. The RP2D was defined as 8 mg once daily. Future studies are warranted. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03420079.

Effect of low-dose ethanol on NLRP3 inflammasome in diabetes-induced lung injury.

To observe the changes in NLR family pyrin domain containing 3 (NLRP3) inflammasome in a rat model of diabetes-induced lung injury, and investigate the effect of low-dose ethanol on the production of NLRP3 inflammasome. The type I diabetic mellitus (DM) rat model was established, and the rats were divided into four groups: normal control group (CON group), low-dose ethanol group (EtOH group), diabetes group (DM group) and DM+EtOH group. The rats were fed for 6 and 12 weeks, respectively. The ratio of lung wet weight/body weight (lung/body coefficient) was calculated, and the changes of pulmonary morphology and fibrosis were observed by HE and Masson staining. The changes in pulmonary ultra-structure were examined by electron microscopy. The expressions of mitochondrial acetaldehyde dehydrogenase 2 (ALDH2) and NLRP3 inflammasome key factors, NLRP3, ASC and caspase-1 proteins were detected by western blot. Compared with the CON group, the lung/body coefficient was increased (P<0.05), lung fibrosis occurred, ALDH2 protein expression was decreased, and NLRP3, ASC and caspase-1 protein expressions were increased in the DM rats (P<0.05). Compared with the DM group, the lung/body coefficient and fibrosis degree were decreased, ALDH2 protein expression was increased (P<0.05), and NLRP3, ASC and caspase-1 protein expressions were decreased in the DM+EtOH group (P<0.05). Hence, low-dose ethanol increased ALDH2 protein expression and alleviated diabetes-induced lung injury by inhibiting the production of NLRP3 inflammasome.

Apelin Rejuvenates Aged Human Mesenchymal Stem Cells by Regulating Autophagy and Improves Cardiac Protection After Infarction.

The protective effects of mesenchymal stem cell (MSC)-based therapy for myocardial infarction (MI) are largely hampered as they age. Apelin is an endogenous ligand of its receptor APJ and plays an essential role in regulating multiple biological activities including MSC proliferation and survival. In this study, we investigated whether Apelin regulates MSC senescence and whether its overexpression could rejuvenate aged MSCs (AMSCs) to improve cardiac protection following infarction in mice. MSC senescence was evaluated by senescence-associated ß-galactosidase assays. Apelin level was examined by western blotting. Autophagy was determined by transmission electron microscopy. The cardioprotective effect of AMSCs with Apelin overexpression (Apelin-AMSCs) was assessed in a mouse MI model. Apelin expression was dramatically reduced in AMSCs. Interestingly, knockdown of Apelin induced young MSCs (YMSC) senescence, whereas overexpression rescued AMSC senescence. Apelin overexpression also increased AMSC angiogenic capacity. Mechanistically, Apelin overexpression upregulated the autophagy level of AMSCs by activating AMP-activated protein kinase (AMPK) signaling, thereby rejuvenating AMSCs. Compared with AMSCs, transplantation of Apelin-AMSCs achieved better therapeutic efficacy for MI by enhancing cell survival and angiogenesis. In conclusion, our results reveal that Apelin activates AMPK to rejuvenate AMSCs by increasing autophagy and promotes cardioprotection following infarction in mice. This study identified a novel target to rejuvenate AMSCs and enhance their therapeutic efficacy.

Chetomin, a Hsp90/HIF1α pathway inhibitor, effectively targets lung cancer stem cells and non-stem cells.

Non-small cell lung cancer (NSCLC) remains recalcitrant to effective treatment due to tumor relapse and acquired resistance. Cancer stem cells (CSCs) are believed to be one mechanism for relapse and resistance and are consequently considered promising drug targets. We report that chetomin, an active component of Chaetomium globosum, blocks heat shock protein 90/hypoxia-inducible factor 1 alpha (Hsp90/HIF1α) pathway activity. Chetomin also attenuated sphere-forming, a stem cell-like characteristic, of NSCLC CSCs (at ~ nM range) and the proliferation of non-CSCs NSCLC cultures and chemoresistant sublines (at ~ µM range). At these concentrations, chetomin exerted a marginal influence on noncancerous cells originating from several organs. Chetomin markedly decreased in vivo tumor formation in a spontaneous KrasLA1 lung cancer model, flank xenograft models, and a tumor propagation flank implanted model at doses that did not produce an observable toxicity to the animals. Chetomin blocked Hsp90/HIF1α pathway activity via inhibiting the Hsp90-HIF1α binding interaction without affecting Hsp90 or Hsp70 protein levels. This study advocates chetomin as a Hsp90/HIF1α pathway inhibitor and a potent, nontoxic NSCLC CSC-targeting molecule.

The circRNA circPTPRA suppresses epithelial-mesenchymal transitioning and metastasis of NSCLC cells by sponging miR-96-5p.

BACKGROUND: Non-small cell lung carcinomas (NSCLC) are prevalent, lethal cancers with especially grim prospects due to late-stage detection and chemoresistance. Circular RNAs (circRNAs) are non-coding RNAs that participate in tumor development. However, the role of circRNAs in NSCLC is not well known. This study investigated the role of one circRNA - circPTPRA- in NSCLC and characterized its molecular mechanism of action. METHODS: circPTPRA expression was analyzed in human NSCLC tumors and matched healthy lung tissue. We performed functional characterization in NSCLC cell lines and a mouse xenograft model of NSCLC to elucidate the molecular role of circPTPRA in epithelial-mesenchymal transitioning (EMT). We also assessed the regulatory action of circPTPRA on the microRNA miR-96-5p and its target the tumor suppressor Ras association domain-containing protein 8 (RASSF8). FINDINGS: circPTPRA was significantly downregulated in NSCLC tumors relative to matched healthy lung tissue. Lower circPTPRA levels correlated with metastasis and inferior survival outcomes in NSCLC patients. circPTPRA suppressed EMT in NSCLC cell lines and reduced metastasis in the murine xenograft model by sequestering miR-96-5p and upregulating RASSF8. Correlation analyses in patient-derived NSCLC tumor specimens supported the involvement of the circPTPRA/miR-96-5p/RASSF8/E-cadherin axis dysregulation in NSCLC tumor progression. INTERPRETATION: circPTPRA suppresses EMT and metastasis of NSCLC cell lines by sponging miR-96-5p, which upregulates the downstream tumor suppressor RASSF8. The circPTPRA/miR-96-5p/RASSF8/E-cadherin axis can be leveraged as a potential treatment avenue in NSCLC. FUND: The Key research and development projects of Anhui Province (201904a0720079), the Natural Science Foundation of Anhui Province (1908085MH240), the Graduate Innovation Program of Bengbu Medical College (Byycx1843), the National Natural Science Foundation of Tibet (XZ2017ZR-ZY033) and the Science and Technology Project of Shannan (SNKJYFJF2017-3) and Academic Subsidy Project for Top Talents in Universities of Anhui in 2019 (gxbjZD16).

Nf1 loss promotes Kras-driven lung adenocarcinoma and results in Psat1-mediated glutamate dependence.

Mutations to KRAS are recurrent in lung adenocarcinomas (LUAD) and are daunting to treat due to the difficulties in KRAS oncoprotein inhibition. A possible resolution to this problem may lie with co-mutations to other genes that also occur in KRAS-driven LUAD that may provide alternative therapeutic vulnerabilities. Approximately 3% of KRAS-mutant LUADs carry functional mutations in NF1 gene encoding neurofibromin-1, a negative regulator of focal adhesion kinase 1 (FAK1). We evaluated the impact of Nf1 loss on LUAD development using a CRISPR/Cas9 platform in a murine model of Kras-mutant LUAD We discovered that Nf1 deactivation is associated with Fak1 hyperactivation and phosphoserine aminotransferase 1 (Psat1) upregulation in mice. Nf1 loss also accelerates murine Kras-driven LUAD tumorigenesis. Analysis of the transcriptome and metabolome reveals that LUAD cells with mutation to Nf1 are addicted to glutamine metabolism. We also reveal that this metabolic vulnerability can be leveraged as a treatment option by pharmacologically inhibiting glutaminase and/or Psat1. Lastly, the findings advocate that tumor stratification by co-mutations to KRAS/NF1 highlights the LAUD patient population expected to be susceptible to inhibiting PSAT1.

LEF1-AS1 contributes to proliferation and invasion through regulating miR-544a/ FOXP1 axis in lung cancer.

Long non-coding RNAs (lncRNAs) are increasingly recognized as important regulators in tumor development. This study aims to investigate the potential role oflncRNALEF1-AS1, in the progression of lung cancer. Quantitative real-time PCR (qRT-PCR) and western blot assays showed that LEF1-AS1 was upregulated while miR-544a was downregulated in lung cancer specimens and cells. Overexpression of LEF1-AS1 led to the enhancement of cell proliferation and invasion, revealed by CCK-8 assay and transwell assay. A negative correlation was found between LEF1-AS1 and miR-544a. BLAST analysis and dual-luciferase assay confirmed that FOXP1 is a downstream effector of miR-544a. Therefore, the LEF1-AS1/miR-544a/FOXP1 axis is an important contributor to lung cancer progression. Collectively, our novel data uncovers a new mechanism that governs tumor progression in lung cancer and provides new targets that may be used for disease monitoring and therapeutic intervention of lung cancer.

miR-193a-3p inhibition of the Slug activator PAK4 suppresses non-small cell lung cancer aggressiveness via the p53/Slug/L1CAM pathway.

L1 cell adhesion molecule (L1CAM) promotes invasiveness and metastasis in non-small cell lung cancer (NSCLC) cells and is upregulated by the p53-regulated transcription factor Slug. p21-activated kinase 4 (PAK4) directly phosphorylates Slug, resulting in pro-malignant Slug stabilization. We hypothesized that microRNA-based negative regulation of PAK4 would reduce L1CAM-induced NSCLC aggressiveness via destabilizing Slug. We found that elevated L1CAM expression was tightly correlated with p53 loss-of-function and reduced NSCLC patient survival. L1CAM suppression reduced NSCLC cell migration and invasiveness in vitro as well as tumor formation and distal metastasis in vivo. Mechanistically, p53 restricts L1CAM expression through the ß-catenin/Slug pathway, with levels of ß-catenin and Slug positively correlating with L1CAM expression in NSCLC tumors. The microRNA miR-193a-3p directly targets PAK4 and suppresses downstream p-Slug and L1CAM expression. Silencing PAK4, Slug, and L1CAM mirrored miR-193a-3p's effects upon the migration and invasiveness of NSCLC cells in vitro. Decreased miR-193a-3p levels correlated with elevated PAK4, p-Slug, and L1CAM levels in NSCLC tumors. Our findings support a model of miR-193a-3p as a suppressor of metastatic disease progression in NSCLC via modulation of the p53/Slug/L1CAM pathway.

Long non-coding RNA-CCAT2 promotes the occurrence of non-small cell lung cancer by regulating the Wnt/ß-catenin signaling pathway.

The present study aimed to investigate the biological function of colon cancer-associated transcript 2 (CCAT2) in the occurrence and progression of non-small cell lung carcinoma (NSCLC) and its potential use in the early diagnosis and molecular-targeted therapy of NSCLC. The tumor tissues, para-carcinoma tissues and associated clinical data of 36 patients with NSCLC were collected in order to detect the expression of CCAT2 and assess the impact of factors including histopathological type, Tumor-Node-Metastasis stage and lymph node metastasis on CCAT2 expression. The lung cancer NCI-H1975 cell line was transfected with a small interfering RNA (siRNA) plasmid to determine the effect of si-CCAT2 on NSCLC proliferation, invasion and metastasis. The effect of si-CCAT2 on the expression of nuclear and cytoplasmic ß-catenin protein in the lung cancer NCI-H1975 cell line was detected using western blot analysis. The expression levels of CCAT2 in the tumor tissues of patients with NSCLC were significantly higher than those in the normal para-carcinoma tissues (t=8.580, P<0.01). Subsequent to CCAT2 silencing, the proliferation and invasive abilities of NCI-H1975 cells were significantly decreased compared with control cells (P<0.05). In the si-CCAT2 group, the level of nuclear and cytoplasmic ß-catenin proteins was decreased, and the activity of the Wnt signaling pathway was significantly inhibited compared with the control cells (P<0.01), and a synergistic effect was exerted with the Wnt signaling inhibitor FH535. CCAT2 may therefore promote the occurrence of NSCLC by regulating the Wnt/ß-catenin signaling pathway.

Knockdown of TBRG4 affects tumorigenesis in human H1299 lung cancer cells by regulating DDIT3, CAV1 and RRM2.

The transforming growth factor ß regulator 4 (TBRG4) gene, located on the 7p14-p13 chromosomal region, is implicated in numerous types of cancer. However, the contribution(s) of TBRG4 in human lung cancer remains unknown. In the present study, the expression of TBRG4 mRNA was investigated in the H1299 lung cancer cell line using the quantitative polymerase chain reaction (qPCR) following the knockdown of TBRG4 by a lentivirus-mediated small interfering RNA (siRNA). Results identified that the expression of TBRG4 within H1299 cells was significantly suppressed (P<0.01) by RNA interference, and 586 genes were differentially expressed following TBRG4 silencing. Ingenuity Pathway Analysis (IPA) revealed that these genes were often associated with infectious diseases, organismal injury, abnormalities and cancer functional networks. Further IPA of these networks revealed that TBRG4 knockdown in H1299 cells deregulated the expression of 21 downstream genes, including the upregulation of DNA damage-inducible transcript 3 (DDIT3), also termed CCAAT/enhancer-binding protein homologous protein, and downregulation of caveolin 1 (CAV1) and ribonucleotide reductase regulatory subunit M2 (RRM2). Results were validated using qPCR and western blotting. Furthermore, immunohistochemical staining of TBRG4 protein identified that expression was markedly increased in carcinoma compared with in normal tissue. In conclusion, TBRG4 serves a role in the tumorigenesis of lung cancer via deregulation of DDIT3, CAV1 and RRM2. The results of the present study may be important in contributing to our understanding of TBRG4 as a target for lung cancer treatment.

Reduced RKIP expression levels are associated with frequent non-small cell lung cancer metastasis and STAT3 phosphorylation and activation.

The current study examined the role of Raf kinase inhibitor protein (RKIP) in non-small cell lung cancer (NSCLC) metastasis. A total of 100 patients with NSCLC were recruited following pathological diagnosis in the First Affiliated Hospital of Bengbu Medical College. The patients were classified and statistically analyzed according to their clinicopathological characteristics and tumor-node-metastasis stage. Paired tumor tissue and adjacent non-tumor tissue samples were subject to pathological diagnosis and western blot analysis. Transient transfection and lentivirus particle vector-mediated RKIP overexpression, small interfering RNA-mediated silencing, Transwell assays and immunocytochemistry methods were employed to elucidate the role and underlying mechanisms of RKIP and the Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway in NSCLC metastasis. Furthermore, in order to examine the in vivo effects of RKIP, recombinant lentivirus particles containing the RKIP gene were administrated in a mouse NSCLC tumor model via tail vein injection. The results revealed reduced RKIP expression levels in NSCLC tissue compared with corresponding non-cancer tissue. Additionally, RKIP expression levels were inversely associated with NSCLC intra-lung, lymph node and long-distance metastasis. The results also indicated that RKIP was able to block STAT3 activation via phosphorylation and inhibit NSCLC-cell metastasis in vitro. Furthermore, RKIP knockdown was able to promote STAT3 phosphorylation and cell metastasis in NSCLC cell lines. During in vivo experiments, RKIP overexpression was able to suppress xenograft tumor metastasis in nude mice. Therefore, RKIP may be an important factor in cancer cell metastasis in patients with NSCLC, and RKIP may inhibit NSCLC-cell invasion by blocking the activation of the JAK/STAT3 signaling pathway.

Aspirin attenuates monocrotaline-induced pulmonary arterial hypertension in rats by suppressing the ERK/MAPK pathway.

This study aimed to investigate the therapeutic effects of aspirin (ASA) and its potential mechanisms of action in monocrotaline (MCT)-induced pulmonary arterial hypertension (PAH) in rats. PAH was induced in a rat model by a single intraperitoneal (IP) injection of MCT. Saline was injected in a control group. Two weeks following MCT injection, right ventricular systolic pressure (RVSP) and systolic blood pressure (SBP) were measured in six rats from each group to confirm establishment of a PAH model. The remaining MCT-treated rats were randomly allocated to receive IP injection of saline, ASA, or ERK1/2 inhibitor PD98059. Four weeks following treatment, RVSP was measured and all rats were sacrificed for histological study. There was no significant difference in SBP in any group two weeks following MCT administration. Nonetheless RVSP was significantly increased in the MCT group compared with the control group. At 6 weeks, ASA treatment remarkably attenuated MCT-induced increased RVSP, RV hypertrophy, and pulmonary artery remodeling compared with the MCT group. The density of pulmonary capillaries in ASA-treated rats was also dramatically increased. Treatment with ASA significantly inhibited the increased p-ERK1/2 and restored the impaired endothelial nitric oxide synthase (eNOS) in MCT-treated rats. This study demonstrated that ASA distinctively attenuates MCT-induced PAH by inhibition of the ERK1/2 signaling pathway.

The DEAD-box RNA helicase 51 controls non-small cell lung cancer proliferation by regulating cell cycle progression via multiple pathways.

The genetic regulation of cell cycle progression and cell proliferation plays a role in the growth of non-small cell lung cancer (NSCLC), one of the most common causes of cancer-related mortality. Although DEAD-box RNA helicases are known to play a role in cancer development, including lung cancer, the potential involvement of the novel family member DDX51 has not yet been investigated. In the current study we assessed the role of DDX51 in NSCLC using a siRNA-based approach. DDX51 siRNA-expressing cells exhibited a slower cell proliferation rate and underwent arrest in S-phase of the cell cycle compared with control cells. Microarray analyses revealed that DDX51siRNA expression resulted in the dysregulation of a number of cell signalling pathways. Moreover, injection of DDX51 siRNA into an animal model resulted in the formation of smaller tumours compared with the control group. We also assessed the expression of DDX51 in patients with NSCLC, and the data revealed that the expression was correlated with patient age but no other risk factors. Overall, our data suggest for the first time that DDX51 aids cell cancer proliferation by regulating multiple signalling pathways, and that this protein might be a therapeutic target for NSCLC.

HIF-1α knockdown by miRNA decreases survivin expression and inhibits A549 cell growth in vitro and in vivo.

The present study examined the downregulation of survivin expression by hypoxia-inducible factor-1α (HIF-1α) miRNA and its effect in the inhibition of A549 cell growth in vitro and in vivo. Survivin expression, apoptosis, proliferation and migration under normoxic and hypoxic conditions were assessed by standard methods. Cotransfection and chromatin immunoprecipitation were used to observe the effects of HIF-1α on survivin transcription. HIF-1α knockdown in A549 cells were injected into nude mice to examine survivin expression and suppression of tumorigenicity. Transfection of A549 cells with HIF-1α miRNA led to decreased expression of HIF-1α and survivin mRNA and protein. Survivin overexpression is mediated by HIF-1α by direct binding to a putative binding site in the survivin core promoter. HIF-1α-miRNA induced apoptosis and inhibited proliferation of A549 cells under hypoxic, but not normoxic, conditions, whereas transfection by survivin expression vectors partly rescued the apoptotic phenotype and revived cell proliferation under hypoxic conditions. However, cell migration was substantially suppressed by HIF-1α silencing under normoxic and hypoxic conditions. After A549 cells were xenografted in nude mice, survivin expression in mice treated with HIF-1α miRNA was downregulated, and tumor growth was significantly inhibited. Silenced HIF-1α gene expression induced apoptosis and suppressed growth of A549 cells by downregulating survivin expression in vitro and in vivo. Our results also provide a basis to target the HIF-1α pathway in lung cancer therapy.

Expression of survivin and patients survival in non-small cell lung cancer: a meta-analysis of the published studies.

Among new biological markers that could become useful prognostic factors for non-small cell lung cancer (NSCLC). Survivin is one of the most commonly over-expressed oncogenes, however, its role in NSCLC remains controversial. We performed a systematic review of the literature with meta-analysis to clarify this issue. Electronic databases were used to identify published studies before August 2011. Pooled hazard ratio (HR) with 95 % confidence interval (95 % CI) was used to estimate the strength of the association of survivin expression with survival of NSCLC patients. Heterogeneity and publication bias were also assessed. Overall 29 relevant published studies including 2,517 lung cancer patients were identified from electronic databases. We found that overexpression of survivin in NSCLC patients might be a poor prognostic factor for survival 1.95 (95 % CI: 1.65-2.29; P < 0.001). Heterogeneity testing indicated that there was heterogeneity among studies. When stratified by histology types, the heterogeneity was absent. We should point out that the publication bias may partly account for the result, but the conclusion might not be affected deeply by the publication bias. When we accounted for publication bias using the trim and fill method, the results remained significant (HR = 1.71, 95 % CI: 1.44-2.02, P < 0.001), suggesting the stability of our results. Therefore, our study suggested that survivin overexpression had a poor prognosis value in patients with NSCLC.

Meta-analysis for cyclin E in lung cancer survival.

BACKGROUND: To assess the prognosis value of cyclin E expression in survival of patients with lung cancer (LC), we performed a systematic review of the literature with meta-analysis. METHODS: Electronic databases were used to identify published studies before August 2011. Pooled hazard ratio (HR) with 95% confidence interval (95% CI) was used to estimate the strength of the association of cyclin E expression with survival of LC patients. Heterogeneity and publication bias were also assessed. RESULTS: Fourteen studies (2606 cases) were eligible and subjected to analysis. Cyclin E over-expression was found to be a strong predictor of poor prognosis in LC patients (HR: 1.38, 95% CI: 1.07-1.79; P=0.014). When only non-small cell lung cancer (NSCLC) was considered, the combined HR was 1.53 (95% CI: 1.19-1.97, P=0.001). A significant association was also evident when the analysis was limited to studies involving adenocarcinoma (AD), but not squamous cell carcinoma (SQ). Publication bias was absent. Sensitivity analyses suggested that the summary statistics obtained should approximate the actual average.

Sp1 upregulates survivin expression in adenocarcinoma of lung cell line A549.

Survivin has been implicated in tumor genesis, progression, and resistance to anticancer agents. However, the precise regulatory mechanism for survivin expression is not thoroughly defined. In this study, we showed that Sp1 was co-overexpressed with survivin in adenocarcinoma of lung cells A549, but not in differentiated human bronchial epithelial cells 4F0439 or small airway epithelial cells 3F1584. Subsequently, transfection experiments demonstrated that the inhibition of Sp1 signaling suppressed survivin expression in A549 cells, whereas Sp1 overexpression increased the level of survivin protein as well as its mRNA. We also found that Sp1 could decrease capase-9 activity, which is shown to be suppressed by survivin during apoptosis inhibition. Finally, Luciferase activity and ChIP assays revealed that Sp1 activated survivin promoter by direct interaction with it. Taken together, our data suggest Sp1 plays a potent role in the upregulation of survivin expression in lung cancer cells at the transcriptional level.