TP63 Functions as a Tumor Suppressor Regulated by GAS5/miR-221-3p Signaling Axis in Human Non-Small Cell Lung Cancer Cells.

Background: Tumor protein p63 (TP63) has been proven to play a role as a tumor suppressor in some human cancers, including non-small cell lung cancer (NSCLC). This study aimed to investigate the mechanism of TP63 and analyze the underlying pathway dysregulating TP63 in NSCLC. Methods: RT-qPCR and Western blotting assays were used to determine gene expression in NSCLC cells. The luciferase reporter assay was performed to explore the transcriptional regulation. Flow cytometry was used to analyze the cell cycle and cell apoptosis. Transwell and CCK-8 assays were performed to test cell invasion and cell proliferation, respectively. Results: GAS5 interacted with miR-221-3p, and its expression was significantly reduced in NSCLC. GAS5, as a molecular sponge, upregulated the mRNA and protein levels of TP63 by inhibiting miR-221-3p in NSCLC cells. The upregulation of GAS5 inhibited cell proliferation, apoptosis, and invasion, which was partially reversed by the knockdown of TP63. Interestingly, we found that GAS5-induced TP63 upregulation promoted tumor chemotherapeutic sensitivity to cisplatin therapy in vivo and in vitro. Conclusion: Our results revealed the mechanism by which GAS5 interacts with miR-221-3p to regulate TP63, and targeting GAS5/miR-221-3p/TP63 may be a potential therapeutic strategy for NSCLC cells.

TFAP4 Activates IGF2BP1 and Promotes Progression of Non-Small Cell Lung Cancer by Stabilizing TK1 Expression through m6A Modification.

Non-small cell lung cancer (NSCLC) is a well-known global health concern. TFAP4 has been reported to function as an oncogene. This study sought to investigate the molecular mechanism of TFAP4 in NSCLC development. Significantly highly-expressed gene IGF2BP1 was screened on online databases and its downstream gene TK1 was predicted. IGF2BP1 promoter sequence was identified. The binding site of TFAP4 and IGF2BP1 was predicted. The expression correlations among TFAP4, IGF2BP1, and TK1 were confirmed. The correlations between TFAP4, IGF2BP1, TK1, and NSCLC prognosis were predicted. NSCLC and paracancerous tissues were collected. The expressions of TFAP4, IGF2BP1, and TK1 were detected. NSCLC cell proliferation, migration, invasion, and apoptosis were detected. The binding of TFAP4 to the IGF2BP1 promoter was verified. m6A modification of TK1 mRNA was detected. The correlation between IGF2BP1 and TK1 was confirmed. A subcutaneous tumor xenograft model was established to validate the effect of TFAP4 in vivo. IGF2BP1 was highly expressed in NSCLC tissues and cells. IGF2BP1 knockdown repressed NSCLC cell proliferation, migration, and invasion and facilitated apoptosis. Mechanically, TFAP4 transcriptionally activated IGF2BP1. IGF2BP1 stabilized TK1 expression via m6A modification and promoted NSCLC cell proliferation, migration, and invasion. In vivo experiments confirmed that TFAP4 knockdown suppressed tumor growth by downregulating IGF2BP1/TK1. IMPLICATIONS: Our findings revealed that TFAP4 activated IGF2BP1 and facilitated NSCLC progression by stabilizing TK1 expression via m6A modification, which offered new insights into the diagnosis and treatment of NSCLC.

LINC01342 silencing upregulates microRNA-508-5p to inhibit progression of lung cancer by reducing cysteine-rich secretory protein 3.

Long noncoding RNAs (lncRNAs) are critical players during cancer progression. Nevertheless, the effect of most lncRNAs in lung cancer (LC) remains unclear. We aimed to explore the role of LINC01342 in LC development through the microRNA-508-5p (miR-508-5p)/cysteine-rich secretory protein 3 (CRISP3) axis. LINC01342, miR-508-5p, and CRISP3 expression in clinical samples and cell lines were determined, and their correlations in LC were analyzed. The prognostic role of LINC01342 in LC patients was evaluated. LC cells were screened and, respectively, transfected to alter the expression of LINC01342, miR-508-5p, and CRISP3. Then, proliferation, migration, invasion, and apoptosis of transfected LC cells were determined, and the in vivo tumor growth was observed as well. Binding relationships between LINC01342 and miR-508-5p, and between miR-508-5p and CRISP3 were identified. LINC01342 and CRISP3 were upregulated and miR-508-5p was downregulated in LC tissues and cells. High LINC01342 expression indicated a poor prognosis of LC patients. The LINC01342/CRISP3 silencing or miR-508-5p elevation inhibited proliferation, migration, and invasion of LC cells and promoted LC cell apoptosis, and also suppressed the in vivo tumor growth. LINC01342 bound to miR-508-5p and miR-508-5p targeted CRISP3. LINC01342 plays a prognostic role in LC and LINC01342 silencing upregulates miR-508-5p to inhibit the progression of LC by reducing CRISP3.

LncRNA SBF2-AS1 affects the radiosensitivity of non-small cell lung cancer via modulating microRNA-302a/MBNL3 axis.

Background: Long non-coding RNAs (lncRNAs) have been reported to participate in many diseases including non-small cell lung cancer (NSCLC), thus our objective was to investigate the impact of lncRNA SBF2-AS1 modulating microRNA-302a (miR-302a) expression on radiosensitivity of NSCLC.Methods: The expression of SBF2-AS1, miR-302a and muscleblind-like 3 (MBNL3) in NSCLC tissues of the radiotherapy-sensitive and radiotherapy-resistant groups was tested. The radiosensitivity of parent and resistant strains (NCI-H1299 and NCI-H1299R cells) was detected. Further, cells were treated with si-SBF2-AS1 and miR-302a mimics to determine their roles in proliferation and apoptosis of parent strain and resistant strain cells as well as transfected cells. The in-vivo growth capacity of the cells and the effect of radiotherapy on tumor size of NSCLC were detected.Results: Up-regulated SBF2-AS1 and MBNL3 and down-regulated miR-302a in NSCLC tissues of the radiotherapy resistant group. Overexpression of SBF2-AS1 and MBNL3 and low expression of miR-302a were witnessed in NCI-H1299R cells. Down-regulated SBF2-AS1 or up-regulated miR-302a suppressed the proliferation while boosted the apoptosis of NCI-H1299 cells and decreased the radioresistance of the NCI-H1299R cells. Silencing SBF2-AS1 or up-regulating miR-302a restrained tumor growth in vivo.Conclusion: Our study presents that high expression of miR-302a or inhibition of SBF2-AS1 can enhance the radiosensitivity and apoptosis of NSCLC cells through downregulation of MBNL3, which is a therapeutic target for NSCLC.

MARCH9 Suppresses Lung Adenocarcinoma Progression by Downregulating ICAM-1.

BACKGROUND/AIMS: To investigate the clinical significance and functional mechanisms of membrane-associated RING-CH protein 9 (MARCH9) in lung adenocarcinoma (LAC). METHODS: Immunohistochemistry staining was performed to explore the expression of MARCH9 in LAC tissues and adjacent normal lung tissues. Patients' prognosis was evaluated using overall survival. The prognostic role of MARCH9 was tested with univariate and multivariate analyses. To confirm the effect of MARCH9 in cell proliferation and invasion, overexpression of MARCH9 was induced in two LAC cell lines. Cell cycle, apoptosis, migration, invasion, and immunoprecipitation experiments were performed to further explore the signaling pathways involved. RESULTS: Analysis of a series of 143 clinical samples revealed that MARCH9 was down-regulated in tumor tissues compared with normal lung tissues, and this was closely associated with lymph node metastasis (P = 0.004). Univariate and multivariate analyses indicated that MARCH9 was an independent prognostic biomarker for LAC; low MARCH9 expression indicated poor overall survival. Cellular studies with A549 and H1299 cells demonstrated that MARCH9 can attenuate tumor migration and invasion but had little effect on cell cycle or apoptosis. Moreover, an interaction between MARCH9 and ICAM-1 protein was identified, and overexpression of MARCH9 was found to attenuate the oncogenic effect of ICAM-1, suggesting that MARCH9 may inhibit tumor progression by downregulating ICAM-1 signaling. CONCLUSION: MARCH9 downregulation in LAC tissues correlated with poor clinical outcomes. MARCH9 may serve as a novel biomarker and potential therapeutic target for LAC.

Effect of exogenous p51a gene on the growth and chemo sensitivity of human lung adenocarcinoma cell lines.

BACKGROUND: The dysfunction of p53-mediated apoptosis is the key to tumorigenesis, so most gene therapy programs concentrate on improving the expressing level of wild-type p53 in tumour cells. However, the p53 gene therapy has not yielded satisfactory results in tumours with normal p53 function. A new member of p53 gene family-p63, has provided new hopes. TAp63γ (p51A) resembles p53 the most, thus it might become a new promising therapeutic gene of tumours. METHODS: We designed the primer pairs of p51A and amplified the p51A cDNA sequence from human skeletal muscle poly A + RNA to construct recombinant plasmid. It was then transfected into human lung adenocarcinoma cell lines A549 and NCI-H1299. RT-PCR, Western blot, MTT, flow cytometry and colony formation assay were used to analyse the growth and chemosensitivity of tumour cells. RESULTS: The recombinant plasmid was constructed and transfected into tumour cells successfully. After transfection, p51A mRNA, P51A protein and P21 protein level raised significantly. Cell proliferation capacity and colony formation rate decreased while cell apoptosis rate and chemosensitivity to cisplatin and adriamycin increased significantly. CONCLUSIONS: Exogenous p51A gene can increase its expression in A549 and NCI-H1299 cells, suppress cell growth and induce cell apoptosis. Moreover, it can also cooperate with chemotherapy and reduce the dose and side-effect. p51A gene can suppress tumours in spite of p53 status and p21 gene might be involved. It might become a new promising therapeutic gene of tumours, which will make up for the limitation of p53 gene therapy.

miR-198-induced upregulation of Livin may be associated with the prognosis and contribute to the oncogenesis of lung adenocarcinoma.

Livin, a member of the inhibitor of apoptosis protein (IAP) family, is expressed at a high level in lung adenocarcinoma and influences the progression of cancer, and its response to chemotherapy and radiotherapy. Aberrant microRNA (miRNA) expression has also been associated with cancer initiation and development. However, the clinical significance of Livin and its relationship with miRNAs in lung adenocarcinoma are still unclear. In the present study, the expression level of Livin in 90 pairs of lung adenocarcinoma and their adjacent tissues were detected by immunohistochemistry staining. Spearman correlation and Kaplan-Meier, univariate and multivariate analyses were applied to evaluate the correlation between the expression of Livin and clinical characteristics. With the integration of bioinformatics analysis and dual-luciferase reporter gene assays, we identified the miRNA that can target Livin mRNA. The functional effects of miRNA-mediated Livin knockdown were assessed by Cell Counting Kit-8 (CCK-8) and apoptosis assays, and cell cycle analysis. The present study revealed that Livin was upregulated in lung adenocarcinoma tissues and may be associated with the poor prognosis in lung adenocarcinoma patients. The overexpression of Livin is partly caused by the downregulation of miR-198. Further exploration revealed that miRNA-198-mediated silencing of Livin significantly inhibited cell growth and enhanced apoptosis of A549 cells, accompanied by marked upregulation of caspase-3. Finally, we observed that the miR-198 overexpression and Livin neutralization had similar effects on improving cisplatin chemosensitivity in A549 cells. Overall, these findings suggest that Livin has the potential to become a biomarker for predicting the prognosis of lung adenocarcinoma and may provide a promising strategy for assisting chemotherapy of lung adenocarcinoma through the miR-198/Livin/caspase-3 regulatory network.

The Long Non-Coding RNA XIST Controls Non-Small Cell Lung Cancer Proliferation and Invasion by Modulating miR-186-5p.

BACKGROUND/AIMS: Long non-coding RNAs (lncRNAs) are key players in the development and progression of human cancers. The lncRNA XIST (X-inactive specific transcript) has been shown to be upregulated in human non-small cell lung cancer (NSCLC); however, its role and molecular mechanisms in NSCLC cell progression remain unclear. METHODS: qRT-PCR was conducted to assess the expression of XIST and miR-186. Cell proliferation was detected using MTT assay. Cell invasion and migration were evaluated using transwell assay. Cell cycle distribution and apoptosis rates were analyzed by flow cytometry. Luciferase reporter assay was used to identify the direct regulation of XIST and miR-186. A RNA immunoprecipitation was used to analyze whether XIST was associated with the RNA-induced silencing complex (RISC). RESULTS: We confirmed that XIST was upregulated in NSCLC cell lines and tissues. Functionally, XIST knockdown inhibited cancer cell proliferation and invasion, and induced apoptosis in vitro, and suppressed subcutaneous tumor growth in vivo. Mechanistic investigations revealed a reciprocal repressive interaction between XIST and miR-186-5p. Furthermore, we showed that miR-186-5p has a binding site for XIST. Our data also indicated that XIST and miR-186-5p are likely in the same RNA induced silencing complex. CONCLUSION: Together, our data revealed that XIST knockdown confers suppressive function in NSCLC and XIST may be a novel therapeutic marker in this disease.

The Evolution of Vicia ramuliflora (Fabaceae) at Tetraploid and Diploid Levels Revealed with FISH and RAPD.

Vicia ramuliflora L. is a widely distributed species in Eurasia with high economic value. For past 200 years, it has evolved a tetraploid cytotype and new subspecies at the diploid level. Based on taxonomy, cytogeography and other lines of evidence, previous studies have provided valuable information about the evolution of V. ramuliflora ploidy level, but due to the limited resolution of traditional methods, important questions remain. In this study, fluorescence in situ hybridization (FISH) and random amplified polymorphic DNA (RAPD) were used to analyze the evolution of V. ramuliflora at the diploid and tetraploid levels. Our aim was to reveal the genomic constitution and parents of the tetraploid V. ramuliflora and the relationships among diploid V. ramuliflora populations. Our study showed that the tetraploid cytotype of V. ramuliflora at Changbai Mountains (M) has identical 18S and 5S rDNA distribution patterns with the diploid Hengdaohezi population (B) and the diploid Dailing population (H). However, UPGMA clustering, Neighbor-Joining clustering and principal coordinates analysis based on RAPD showed that the tetraploid cytotype (M) has more close relationships with Qianshan diploid population T. Based on our results and the fact that interspecific hybridization among Vicia species is very difficult, we think that the tetraploid V. ramuliflora is an autotetraploid and its genomic origin still needs further study. In addition, our study also found that Qianshan diploid population (T) had evolved distinct new traits compared with other diploid populations, which hints that V. ramuliflora evolved further at diploid level. We suggest that diploid population T be re-classified as a new subspecies.

Role of fibulin-3 in lung cancer: in vivo and in vitro analyses.

Lung cancer was the most commonly diagnosed cancer in 2008 worldwide. The level of fibulin-3 expression was found to be decreased in many cancer types due to aberrant promoter methylation and is correlated with poor survival of patients. However, the role of fibulin-3 and which form of fibulin-3 is expressed in lung cancer cells remain unclear. Therefore, pathologic and functional studies were carried out to determine the role of fibulin-3 in suppressing lung cancer both in vivo and in vitro. In the present study, we found that the levels of fibulin-3 mRNA and protein were lower in cancer tissues than in normal tissues. Downregulation of fibulin-3 mRNA in tumor tissues was associated with an increase in fibulin-3 promoter methylation. Circulating fibulin-3 was significantly associated with tumor progression, survival rate of lung cancer patients, and the number of circulating tumor cells (CTCs). To examine the effects of exogenous expression of fibulin-3 in vitro, lung cancer A549 cells were transfected with the pEGFP-C1-fibulin-3 expression vector. Relative to the untreated cells, fibulin-3-expressing cells exhibited lower proliferation and mobility as determined by MTT and Transwell assays, respectively. To conclude, our results suggest that fibulin-3 negatively modulates the invasiveness of lung cancer cells via regulation of p38-MAPK and MMP-2/9.

Genetic diversity and phylogenetic relationships of two closely related northeast China Vicia species revealed with RAPD and ISSR markers.

RAPD and ISSR analyses revealed genetic diversity and relationships among 11 populations of two closely related northeast China Vicia species, Vicia ramuliflora and V. unijuga. Both methods yielded similar and complementary results, showing high genetic diversity. Vicia ramuliflora had 100% polymorphic loci in both RAPD and ISSR, and V. unijuga had 100% polymorphic loci for RAPD and 98.96% for ISSR. Genetic differentiation was moderate among populations of each species. Genetic variation was distributed mainly within populations for the two species. The high level of gene flow was important for the allocation of genetic variation. The UPGMA dendrogram and principal coordinates analysis at the level of individuals and populations showed that V. ramuliflora and V. unijuga were more closely related than either of them was to the outgroup species, V. cracca. The small molecular variance of V. ramuliflora and V. unijuga supports the conclusion that these two species had a common ancestor.