The m6A demethylase FTO promotes the growth of lung cancer cells by regulating the m6A level of USP7 mRNA.

Lung cancer is one of the leading causes of cancer-related death in developed countries. Despite decades of intensive efforts to comate this malignant disease, the prognosis of lung cancer remains unfavorable and is especially poor in advanced non-small cell lung cancer (NSCLC). However, whether and how the m6A demethylase FTO functions in lung cancer cells remain unknown. Here in the present study, we show that FTO plays an oncogenic role in human NSCLC. FTO mRNA and protein levels were overexpressed in human NSCLC tissues and cell lines, which was associated with the reduced m6A content. We next knocked down FTO expression in human lung cancer cell lines with lentivirus-mediated shRNAs and the cellular proliferation assay demonstrated that FTO loss-of-function reduced the proliferation rate of cancer cells. FTO knockdown also inhibited the colony formation ability of lung cancer cells. Importantly, our xenograft experiment showed that FTO knockdown reduced lung cancer cells growth in vivo. Mechanism analysis demonstrated that FTO decreased the m6A level and increased mRNA stability of ubiquitin-specific protease (USP7), which was relied on the demethylase activity of FTO. USP7 mRNA level was overexpressed in human lung cancer tissues and USP7 expression was positively correlated with FTO mRNA level. Genetic knockdown or pharmacological inhibition (P5091 or P22027) of USP7 reduced the proliferation rate of lung cancer cells and decreased the capacity of colony formation of lung cancer cells in vitro, whereas lung cancer cells growth inhibition by FTO knockdown is restored by overexertion of USP7. Collectively, our findings demonstrate that the m6A demethylase FTO promotes the growth of NSCLC cells by increasing the expression of USP7.

Investigating the mechanism by which SMAD3 induces PAX6 transcription to promote the development of non-small cell lung cancer.

BACKGROUND: This study investigated the function of SMAD3 (SMAD family member 3) in regulating PAX6 (paired box 6) in non-small cell lung cancer. METHODS: First, qRT-PCR was employed to detect SMAD3 expression in cancer tissues along with normal tissues and four cell lines, including BEAS-2B, H125, HCC827 and A549 cells. SMAD3 was knocked down by small interference RNA (siRNA), and then its expression was determined via qRT-PCR and Western blot analysis. The correlation between SMAD3 and PAX6 was determined by double luciferase reporter experiments and chromatin immunoprecipitation (ChIP) assay. Cell viability was evaluated by CCK-8 and colony forming assays, while cell migration and invasion were detected by Transwell analysis. RESULTS: SMAD3 and PAX6 were upregulated in lung cancer tissues and cancer cells. Knocking down SMAD3 and PAX6 by transfection with siRNAs specifically suppressed the expression of SMAD3 and PAX6 mRNA and protein levels. SMAD3 could promote PAX6 transcriptional activity by binding to its promoter. Reduced expression of SMAD3 led to the downregulation of PAX6 mRNA and protein levels along with decreased cell migration, invasion, proliferation and viability in A549 and HCC827 cells. PAX6 overexpression altered the si-SMAD3-induced inhibition of cell migration, invasion, proliferation and viability in A549 and HCC827 cells. Additionally, PAX6 knockdown alone also repressed the cell migration, invasion, proliferation and viability of the cell lines. CONCLUSIONS: SMAD3 promotes the progression of non-small cell lung cancer by upregulating PAX6 expression.

Clinical significance of serum and tumor tissue endostatin evaluation in operable non-small cell lung cancer.

Endostatin, as the most potential antiangiogenic factor, is a naturally occurring fragment of collagen XVIII in bloodstream capable of inhibiting tumor growth and metastasis. This study was conducted to explore the clinical value of endostatin in serum and tumor tissue in patients with operable non-small cell lung cancer (NSCLC). ELISA and immunohistochemistry were applied to detect the expression of endostatin in serum and tumor tissue in 105 patient-matched operable NSCLC patients. The serum level of endostatin was significantly higher in NSCLC patients than healthy individuals (P=0.0018). Cases with poorer differentiation showed a higher endostatin serum level (P=0.008). There was no significant correlation between tumor tissue expression and clinical parameters, such as TNM stage, differentiation degree, histological type and lymph node invasion status. A stronger expression of endostain in tumor tissue was associated with a higher serum level (r=0.223). The univariate and multivariate analyses with Cox proportional hazards model for overall survival showed that tumor stage and node status were independent prognostic factors, whereas neither endostatin levels in serum nor in tumor tissue showed potential in predicting the long-term survival of operable NSCLC patients. In conclusion, the results observed in the present study did not support the prediction of overall survival in operable NSCLC based on the expression levels of endostatin in serum and tumor tissue.

Downregulation of PAX6 by shRNA inhibits proliferation and cell cycle progression of human non-small cell lung cancer cell lines.

BACKGROUND: The transcription factor PAX6 is primarily expressed in embryos. PAX6 is also expressed in several tumors and plays an oncogenic role. However, little is known about the role of PAX6 in lung cancer. METHODS: The function of PAX6 in lung cancer cells was evaluated by small interfering RNA-mediated depletion of the protein followed by analyses of cell proliferation, anchorage-independent growth, and cell cycle arrest. The changes of cyclin D1, pRB, ERK1/2, p38 expression caused by PAX6 inhibition were detected using western-blotting. The PAX6 mRNA level in 52 pairs of tumors and corresponding matched adjacent normal tissues from non-small cell lung cancer patients and lung cancer cell lines was detected by real-time PCR. RESULTS: Suppression of PAX6 expression inhibited cell growth and colony formation in A549 and H1299 cells. The percentage of cells in G1-phase increased when PAX6 expression was inhibited. The cyclin D1 protein level, as well as the pRB phosphorylation level, decreased as a result of PAX6 down-regulation. The activity of ERK1/2 and p38 was also suppressed in PAX6 knock-down cells. The PAX6 mRNA was highly expressed in lung cancer tissue and lung cancer cell lines. In most patients (about 65%), the relative ratio of PAX6 mRNA in primary NSCLC versus adjacent tissues exceeded 100. CONCLUSIONS: Our data implicated that PAX6 accelerates cell cycle progression by activating MAPK signal pathway. PAX6 mRNA levels were significantly elevated in primary lung cancer tissues compared to their matched adjacent tissues.

Downregulation of cyclophilin A by siRNA diminishes non-small cell lung cancer cell growth and metastasis via the regulation of matrix metallopeptidase 9.

BACKGROUND: Cyclophilin A (CypA) is a cytosolic protein possessing peptidyl-prolyl isomerase activity that was recently reported to be overexpressed in several cancers. Here, we explored the biology and molecular mechanism of CypA in non-small cell lung cancer (NSCLC). METHODS: The expression of CypA in human NSCLC cell lines was detected by real-time reverse transcription PCR. The RNA interference-mediated knockdown of CypA was established in two NSCLC cell lines (95C and A549). 239836 CypA inhibitor was also used to suppress CypA activity. Tumorigenesis was assessed based on cellular proliferation, colony formation assays, and anchorage-independent growth assays; metastasis was assessed based on wound healing and transwell assays. RESULTS: Suppression of CypA expression inhibited the cell growth and colony formation of A549 and 95C cells. CypA knockdown resulted in the inhibition of cell motility and invasion. Significantly, we show for the first time that CypA increased NSCLC cell invasion by regulating the activity of secreted matrix metallopeptidase 9 (MMP9). Likewise, suppression of CypA with 239836 CypA inhibitor decreased cell proliferation and MMP9 activity. CONCLUSIONS: The suppression of CypA expression was correlated with decreased NSCLC cell tumorigenesis and metastasis.

Cell cycle protein cyclin Y is associated with human non-small-cell lung cancer proliferation and tumorigenesis.

BACKGROUND: The role of cell cycle protein cyclin Y (CCNY) in non-small-cell lung cancer (NSCLC) is not clear. Hence, the aim of this study was to explore the potential role of CCNY in lung cancer. PATIENTS AND METHODS: Real-time quantitative polymerase chain reaction was used for detecting the expression of CCNY mRNA in 60 samples from patients with NSCLC. The functional role of CCNY in NSCLC cells was evaluated by small interfering RNA-mediated depletion of the protein followed by analysis of cell proliferation, anchorage-independent growth, and xenograft growth. RESULTS: CCNY mRNA is overexpressed (N = 60) in samples from patients with NSCLC. Furthermore, CCNY mRNA expression positively correlated with histologic types (squamous cell carcinoma vs. adenocarcinomas; P = .048) and with the tumor size (size > 3 cm vs. size ≤ 3 cm; P = .010) in NSCLC. Functionally, CCNY depletion was shown to inhibit cell proliferation and anchorage-independent growth in lung cancer cells. Moreover, the proliferation effects were increased when CCNY was overexpressed in lung cancer cells. Finally, CCNY was shown to support H1299 and 95D xenograft growth in nude mice. CONCLUSION: We reported for the first time (to the best of our knowledge) that CCNY was overexpressed in samples of NSCLC. CCNY mRNA expression associated with histologic types of NSCLC and promoted the malignant growth of lung cancer cell line in vivo and in vitro. Thus, these results validated the role of CCNY as a clinically relevant human oncoprotein and warrant further investigation of CCNY as a biomarker and a therapeutic target in NSCLC.

Overexpression of cyclin Y in non-small cell lung cancer is associated with cancer cell proliferation.

Cyclin Y (CCNY) is a key cell cycle regulator that acts as a growth factor sensor to integrate extracellular signals with the cell cycle machinery. The expression status of CCNY in lung cancer and its clinical significance remain unknown. The data indicates that CCNY may be deregulated in non-small cell lung cancer, where it may act to promote cell proliferation. These studies suggest that CCNY may be a candidate biomarker of NSCLC and a possible therapeutic target for lung cancer treatment.