Tianjun Chen

Downregulation of miR-25 modulates non-small cell lung cancer cells by targeting CDC42.

The current study aims to investigate the fuctional role of miRNA-25 in non-small cell lung cancer (NSCLC) cells. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the expression of miR-25 in NSCLC cell lines and 11 pairs of human NSCLC and non-cancerous tissues. The inhibitor of miR-25 was stably transfected into NSCLC cell line A549 cells. Then the effects of downregulating miR-25 on cancer cell proliferation, cell cycle arrest, chemosensitivity to cisplatin, and growth of in vivo xenograft were investigated. Direct regulation of miR-25 on its target gene, cell division cycle 42 (CDC42), was examined by luciferase reporter assay, qRT-PCR and western blot. CDC42 was then upregulated in A549 cells to investigate its effect on miR-25-mediated NSCLC cell proliferation and cell cycle arrest. The expression of miR-25 in NSCLC cells or human tissues was significantly higher than that in normal lung cells or adjacent non-cancerous tissues, respectively. Downregulation of miR-25 markedly inhibited A549 cell proliferation, induced G1 cell cycle arrest, increased cisplatin sensitivity, and suppressed the growth of caner cell xenograft in vivo. CDC42 was confirmed to be the directly regulated by miR-25 in A549 cells. Upregulation of CDC42 in A549 cells rescued the inhibitory effect on proliferation and the G1 cell cycle arrest induced by miR-25 downregulation. Our study demonstrates miR-25, by targeting CDC42, is an important regulator in NSCLC.

Diagnostic significance of S100A2 and S100A6 levels in sera of patients with non-small cell lung cancer.

Biochemical markers play a significant role in the diagnosis of lung cancer. Recent studies have demonstrated a link involving S100 Calcium Binding Proteins (S100A2, S100A6) and non-small cell lung cancer (NSCLC), but the expediency of their serum levels in NSCLC has not been established. In this study, we evaluate the potential of serum S100A2 and S100A6 levels as diagnostic markers for NSCLC. Enzyme-linked immunosorbent assay (ELISA) was performed to detect the levels of S100A2 and S100A6 in 141 NSCLC patients and 150 healthy subjects. Serum levels of the two proteins in patients with NSCLC were higher compared to healthy controls (P = 0.0002 for S100A2 and P < 0.0001 for S100A6). Moreover, the levels of S100A2 and S100A6 were higher in the sera of stage I/II NSCLC patients compared to healthy controls with P = 0.01 and <0.0001, respectively. Receiver operating characteristic (ROC) analysis showed that S100A2 could distinguish NSCLC patients from healthy controls (AUC = 0.646), and S100A6 could also identify NSCLC (AUC = 0.668). Meanwhile, these two proteins showed notable capabilities for distinguishing stage I/II NSCLC from healthy controls (AUC = 0.708 for S100A2 and AUC = 0.702 for S100A6). Our results indicate that serum levels of S100A2 and S100A6 are significantly elevated in early stage NSCLC and may have the potential for NSCLC biomarker. Further studies with large sample population would help validate our findings.

miR-382 inhibits tumor progression by targeting SETD8 in non-small cell lung cancer

Previous studies showed that miR-382 plays important roles in several types of cancers. Nevertheless, its expression and function in non-small cell lung cancer (NSCLC) remains largely unknown. In this study, we found that miR-382 expression was evidently downregulated in NSCLC tissue and cell lines in comparison with the adjacent normal tissues and human bronchial epithelial cell line (16HBE). Moreover, the expression levels of miR-382 were significantly associated with last-stage and tumor metastasis in NSCLC patients. In addition, exogenous miR-382 evidently inhibited NSCLC cell proliferation, migration and invasion in vitro. We also revealed SETD8 as a direct target of miR-382 in NSCLC, and restored SETD8 partially reversed the negative effects miR-382 on NSCLC cells. In total, our study demonstrated that miR-382 dysregulated in NSCLC and involved in NSCLC tumorigenesis and metastasis by suppressing SETD8 expression, which may help to identify effective therapies for NSCLC treatment.

NBM-T-BMX-OS01, an Osthole Derivative, Sensitizes Human Lung Cancer A549 Cells to Cisplatin through AMPK-Dependent Inhibition of ERK and Akt Pathway

Background: Drug combination therapies using cisplatin and natural products are common practice in the treatment of human lung cancer. Osthole is a natural compound extracted from a number of medicinal plants and has been shown to exert strong anticancer activities with low toxicity. Methods: In the present study, NBM-T-BMX-OS01 (BMX), derived from the semi-synthesis of osthole, was evaluated in cisplatin treated A549 cells to investigate its effect on cisplatin resistance in human lung cancer. The anticancer effect of BMX were measured by cell viablity‚ colony formation‚ TUNEL staining‚ flow cytometry and cell cycle assay. The fluorescence staining was performed to detect intracellular and mitochondrial reactive oxygen species (ROS) generation. Western blot analysis, antagonists pretreatment and small interfering RNA (siRNA) transfection were used to determine the potential mechanism. Results: It was found that, in comparison with single cisplatin treatment, the combination of BMX and cisplatin resulted in greater efficacy in inhibition of proliferation and colony formation, apoptosis induction and cell cycle arrest. The results of fluorescence staining showed that the combination effect of BMX and cisplatin was due to oxidative stress induced by mitochondrial ROS generation. In addition, BMX significantly attenuated the phosphorylation of ERK and Akt, two important pro-survival kinases. In contrast, BMX inhibited the activation of AMPK, and knockdown of AMPK using specific siRNA partially reversed BMX-induced inhibition of ERK and Akt, as well as its synthetic effects on cisplatin induced anticancer activity in A549 cells. Conclusion: Taken together, this study provides that BMX might modulate cisplatin resistance through AMPK-ERK and AMPK-Akt pathways. These results also support the role of BMX as a potential drug candidate for use in combination with cisplatin in the treatment of human lung cancer.

MicroRNA-134 regulates lung cancer cell H69 growth and apoptosis by targeting WWOX gene and suppressing the ERK1/2 signaling pathway

MicroRNAs have been shown to act as crucial modulators during carcinogenesis. Recent studies have implied that miR-134 expression associated with epithelial-to-mesenchymal transition phenotype and invasive potential of NSCLC cells. Our study investigated the pathogenic implications of miR-134 in small cell lung cancer (SCLC). Overexpression or inhibition MiR-134 expression by miR-134 mimics or miR-134 inhibitors (anti-miR-134) in SCLC cell lines was detected using qRT-PCR. Lactate dehydrogenase (LDH) assay, MTT assays and flow cytometry were performed in order to clarify the growth and apoptosis of SCLC cells which had been transfected with miR-134 mimics or anti-miR-134. WWOX expression in H69 cells was detected by qRT-PCR and western blot, respectively. The results showed that overexpression miR-134 was significantly promoting SCLC cells growth and inhibit its apoptosis. In addition, reduced miR-134 expression was significantly correlated with cell growth inhibition and apoptosis promotion. Furthermore, transfection of miR-134 mimics into the SCLC cells markedly down-regulated the level of WWOX, whereas, anti-miR-134 up-regulated WWOX expression. We also found that overexpression WWOX attenuate miR-134 induced H69 cells growth, and promote cell apoptosis. Moreover, miR-134 promoted cell proliferation and inhibit apoptosis via the activation of ERK1/2 pathway. These findings suggest that miR-134 may be an ideal diagnostic and prognostic marker, and may be attributed to the molecular therapy of SCLC.

Polymorphisms in the TERT gene are associated with lung cancer risk in the Chinese Han population.

Lung cancer has the highest mortality rate among cancers; however, its nosogenesis is still unclear. Genome-wide association studies have shown that the telomerase reverse transcriptase (TERT) gene, located in the chromosome 5p15.33 region, is one of the genes associated with the risk of lung cancer. In this case–control study, we genotyped 11 tag single-nucleotide polymorphisms of the TERT gene to evaluate their association with lung cancer risk in the Han Chinese population. Two tag single-nucleotide polymorphisms were found to be associated with lung cancer risk on using the &khgr;2-test: rs4246742 [odds ratio (OR)=0.77, 95% confidence interval (CI) 0.60–0.98; P=0.03] and rs2853672 (OR=1.26, 95% CI 1.01–1.57; P=0.045). By using SNPStats software we also found rs2242652 (OR=1.47, 95% CI 1.02–2.13; P=0.04) in the dominant model and rs2736098 (OR=1.38, 95% CI 1.06–1.80; P=0.017), rs2853672 (OR=1.41, 95% CI 1.11–1.80; P=0.0048), and rs4246742 (OR=0.75, 95% CI 0.58–0.97; P=0.029) in the log-additive model. ‘T/C-T/T’ of rs10069690 conferred an increased risk for male sex in the dominant model (OR=1.80, 95% CI, 1.05–3.08; P=0.03) and ‘TC’ increased risk for male sex in the overdominant model (OR=1.85, 95% CI, 1.08–3.17; P=0.031). Our findings, combined with previous studies, suggest that polymorphisms in the TERT gene contribute to the risk for lung cancer in the Chinese Han population.

Blockade efficacy of MEK/ERK-dependent autophagy enhances PI3K/Akt inhibitor NVP-BKM120's therapeutic effectiveness in lung cancer cells

NVP-BKM120 (BKM120) is a new pan-class I phosphatidylinositol-3 kinase (PI3K) inhibitor and has been tested in clinical trials as an anticancer agent. In this study, we determined whether BKM120 induces autophagy and the impact of autophagy induction on BKM120s growth-inhibitory activity. BKM120 potently induced elevation of autophagosome-bound type II LC3 (LC3-II) protein, predominantly in cell lines insensitive to BKM120, thereby inducing autophagy. The presence of lysosomal protease inhibitor chloroquine further enhanced the levels of LC3-II. BKM120 combined with chloroquine, enhanced growth-inhibitory effects including induction of apoptosis, suggesting that autophagy is a protective mechanism counteracting BKM120s growth-inhibitory activity. Interestingly, BKM120 increased p-ERK1/2 levels. When blocking the activation of this signaling with MEK inhibitors or with knockdown of ERK1/2, the ability of BKM120 to increase LC3-II was attenuated and the growth-inhibitory effects including induction of apoptosis were accordingly enhanced, suggesting that the MEK/ERK activation contributes to BKM120-induced authophagy. In mouse xenograft model, we also found that the combination of BKM120 and PD0325901 synergistically suppressed cell growth in human lung cancer cells. Thus, the current study not only reveals mechanisms accounting for BKM120-induced autophagy, but also suggests an alternative method to enhance BKM120s therapeutic efficacy against non-small cell lung cancer(NSCLC) by blocking autophagy with either a lysosomal protease inhibitor or MEK inhibitor.

FOXP4 modulates tumor growth and independently associates with miR-138 in non-small cell lung cancer cells.

Family of forkhead box transcription factors, including forkhead box P4 (FOXP4), plays an important role in oncogenesis. The current study is to evaluate the role of FOXP4 in regulating human non-small cell lung cancer (NSCLC). Quantitative RT-PCR and Western blot were performed to evaluate the gene and protein expressions of FOXP4 in six NSCLC cell lines and 55 NSCLC patients. Lentivirus of small hairpin RNA (FOXP4-shRNA) was used to downregulate FOXP4 in NSCLC cell lines A549 and H1703 cells. Its effect on NSCLC growth, invasion, and cell cycle were evaluated by cell proliferation assay, migration assay, and cell cycle assay, respectively. Dual luciferase assay and Western blot were used to examine whether microRNA-138 (miR-138) was an upstream regulator of FOXP4. The dependence of FOXP4 on miR-138 associated signaling pathway was evaluated by ectopically overexpressing enhancer of zeste homolog 2 (EZH2), a known miR-138 target in NSCLC. FOXP4 was highly expressed in both NSCLC cell lines and NSCLC patients. FOXP4 downregulation by FOXP4-shRNA markedly reduced cancer cell growth and invasion, as well as induced cell cycle arrest in A549 and H1703 cells. MiR-138 was confirmed to be an upstream regulator of FOXP4 and directly regulated FOXP4 expression in A549 and H1703 cells. FOXP4 downregulation-mediated inhibition on cancer cell growth and invasion was independent on overexpressing EZH2, another direct target of miR-138 in NSCLC. Our data demonstrated that FOXP4 was a critical regulator in NSCLC and independently associated with miR-138 regulation.

Atypical Presentation of Tracheobronchopathia Osteochondroplastica: Is Chronic Inflammation a Perpetrator?

Objective: To report an atypical presentation of tracheobronchopathia osteochondroplastica (TO). Clinical Presentation and Intervention: A 59-year-old man was investigated for productive cough of 1 month. An antimycobacterial combination regime was initiated with a misdiagnosis of endobronchial tuberculosis. At follow-up, the patient reported worsening of his symptoms. CT revealed an increased intensity of the cartilage ring surrounding the trachea, and bronchoscopy showed tracheal stenosis with white, hard nodules on the airway submucosa. Histopathology confirmed the diagnosis of TO. Conclusion: This case showed that TO should be considered in patients with cough not explained by noninvasive testing and not responsive to empiric medications.

Descriptive data on cancerous lung lesions detected by auto-fluorescence bronchoscope: A five-year study

BACKGROUND: Auto-fluorescence bronchoscopy (AFB) has been used for the identification and localization of intra-epithelial pre-neoplastic and neoplastic lesions within the bronchus. OBJECTIVES: To determine the applicability of AFB for the detection and localization of precancerous and cancerous lesions, in addition to analyzing the morphologic presentation, their association to histological type and the variation between genders. METHODS: A five-year study involving 4983 patients, who underwent routine bronchoscopy [B] examination in a local tertiary teaching hospital, was done. The B examination was performed under intratracheal lidocaine, and samples were obtained using suitable approach. One thousand four hundred and eighty-five pathologically confirmed lung cancer patients were included in the study. The following parameters were studied: Morphological presentation, biopsy sites, histology. Differences between the groups were analyzed using Chi square test. RESULT: One thousand four hundred and eighty-five patients who had hyperplasia or neoplastic lesions were further confirmed as lung cancer pathologically. Lung cancer was more commonly found in the right lung (51.58% vs. 42.82%). The lesion occurred more frequently in the upper lobe than the lower lobe (44.17% vs. 22.42%). Male patients with squamous cell carcinoma showed upper lobe involvement more commonly, while the left main bronchus was more commonly involved in female patients. Adenocarcinoma mostly involved lesion of the upper lobe. Squamous cell carcinoma and small cell carcinoma were the major proliferative types (80.15% and 76.16% respectively). CONCLUSION: AFB is efficient in the detection of pre-invasive and invasive lung lesions. The morphological presentation is associated to the histological type. There is variation in the presentation and histology of cancerous lung lesions between genders.