We have previously shown that miR-486-5p is one of the most downregulated micro RNAs in lung cancer. The objective of the study was to investigate the role of miR-486-5p in the progression and metastasis of non-small-cell lung cancer (NSCLC). We evaluated miR-486-5p expression status on 76 frozen and 33 formalin-fixed paraffin-embedded tissues of NSCLC by quantitative reverse transcriptase PCR to determine its clinicopathologic significance. We then performed function analysis of miR-486-5p to determine its potential roles on cancer cell migration and invasion in vitro and metastasis in vivo. We also investigated the target genes of miR-486-5p in lung tumorigenesis. miR-486-5p expression level was significantly lower in lung tumors compared with their corresponding normal tissues (P<0.0001), and associated with stage (P =0.0001) and lymph node metastasis of NSCLC (P = 0.0019). Forced expression of miR-486-5p inhibited NSCLC cell migration and invasion in vitro and metastasis in mice by inhibiting cell proliferation. Furthermore, ectopic expression of miR-486-5p in cancer cells reduced ARHGAP5 expression level, whereas miR-486-5p silencing increased its expression. Luciferase assay demonstrated that miR-486-5p could directly bind to the 3′-untranslated region of ARHGAP5. The expression level of miR-486-5p was inversely correlated with that of ARHGAP5 in lung tumor tissues (P =0.0156). Reduced expression of ARHGAP5 considerably inhibited lung cancer cell migration and invasion, resembling that of miR-486-5p overexpression. miR-486-5p may act as a tumor-suppressor contributing to the progression and metastasis of NSCLC by targeting ARHGAP5. miR-486-5p would provide potential diagnostic and therapeutic targets for the disease.

Traces of zinc oxide nanoparticles (ZnO NPs) used may be found in the liver and kidney. The aim of this study is to determine the optimal viability assay for using with ZnO NPs and to assess their toxicity to human hepatocyte (L02) and human embryonic kidney (HEK293) cells. Cellular morphology, mitochondrial function (MTT assay), and oxidative stress markers (malondialdehyde, glutathione (GSH) and superoxide dismutase (SOD)) were assessed under control and exposed to ZnO NPs conditions for 24 h. The results demonstrated that ZnO NPs lead to cellular morphological modifications, mitochondrial dysfunction, and cause reduction of SOD, depletion of GSH, and oxidative DNA damage. The exact mechanism behind ZnO NPs toxicity suggested that oxidative stress and lipid peroxidation played an important role in ZnO NPs-elicited cell membrane disruption, DNA damage, and subsequent cell death. Our preliminary data suggested that oxidative stress might contribute to ZnO NPs cytotoxicity.

Whereas pre-hearing spiral ganglion neurons (SGNs) rely faithfully on outputs from spontaneously active developing hair cells, the electrical phenotypes of post-hearing neurons are shaped by distinct rapid and graded receptor potentials from hair cells. To date, technical difficulties in isolation of fragile post-hearing neurons from the rigid bony labyrinth of the inner ear have hindered analyses of the electrical phenotype of SGNs. Therefore, we have recently developed new strategies to isolate post-hearing mouse SGNs for functional analyses. Here, we describe the coarse and fine properties of Ca2+ currents, which sculpt the firing properties of post-hearing SGNs. Murine SGNs express multiple Ca2+ channel currents to confer diverse functions. We have demonstrated that suppression of Ca2+ currents results in significant hyperpolarization of the resting membrane potential (rmp) of basal SGNs, suggesting that Ca2+ influx primes rmp for excitation. In contrast, removal of external Ca2+ has modest effects on rmp of apical SGNs. The blockade of Ca2+ currents with a cocktail of specific blockers attenuates spontaneously active SGNs. Paradoxically, different subtypes of Ca2+ currents, such as R-type currents, may activate resting outward conductances since blockage of the current results in depolarization of rmp. In keeping with whole-cell current data, single channel records revealed multiple diverse Ca2+ channels in SGNs. Additionally, there were differential expressions of distinct Ca2+ current-densities in the apico-basal contour of the adult cochlea. This report provides invaluable insights into Ca2+-dependent processes in adult SGNs.

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BackgroundPim-1 kinase is a proto-oncogene and its dysregulation contributes to tumorigenesis and progression of a variety of malignancies. Pim-1 was suggested as a therapeutic target of cancers. The functional relevance of Pim-1 and the mechanism underlying its dysregulation in lung tumorigenesis remained unclear. This study aimed to investigate if Pim-1 has important functions in non-small-cell lung cancer (NSCLC) by: 1) evaluating the clinicopathologic significance of Pim-1 through analysing its expression in 101 human NSCLCs tissues using quantitative PCR, Western Blot and immunohistochemical studies, 2) determining its role in NSCLC and drug resistance using in vitro assays, and 3) investigating the regulatory mechanism of Pim-1 dysregulation in lung tumorigenesis.ResultsPim-1 was upregulated in 66.2% of the lung tumor tissues and its expression was significantly related to advanced stage (P = 0.019) and lymph node metastasis (P = 0.026). Reduced Pim-1 expression suppressed NSCLC cell growth, cell cycle progression and migration in vitro. Pim-1 was a novel target of miR-486-5p determined by luciferase report assay, and ectopic miR-486-5p expression in cancer cells reduced Pim-1 expression. Furthermore, eukaryotic translation initiation factor 4E (eIF4E) controlled the synthesis of Pim-1 in NSCLC cells, and its expression was positively associated with that of Pim-1 in NSCLC tissue specimens (r = 0.504, p < 0.001). The downregulated miR-486-5p and upregulated eIF4E in NSCLC cells led to the overexpression of Pim-1 by relieving the inhibitory effect of the 3′-UTR or 5′-UTR of Pim-1 mRNA, respectively. Moreover, Pim-1 knockdown sensitized NSCLC cells to cisplatin and EGFR tyrosine kinase inhibitor, gefitinib.ConclusionsPim-1 kinase could be a critical survival signaling factor in NSCLC, and regulated by miR-486-5p and eIF4E. Pim-1 kinase may provide a potential target for diagnosis and treatment for lung cancer.Electronic supplementary materialThe online version of this article (doi:10.1186/1476-4598-13-240) contains supplementary material, which is available to authorized users.

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Long noncoding RNAs (lncRNAs) are emerging as key regulators in cancer initiation and progression. TP53TG1 is a recently identified lncRNA and several studies have shown that TP53TG1 may play the role of tumor suppressor gene or oncogene in different tumors. Nevertheless, the involvement of TP53TG1 in carcinogenesis of pancreatic ductal adenocarcinoma (PDAC) has not been characterized. In our studies, we identified that TP53TG1 was highly expressed in PDAC and was a novel regulator of PDAC development. Knockdown of TP53TG1 inhibited proliferation, induced apoptosis, and decreased migration and invasion in PDAC cells, whereas enhanced expression of TP53TG1 had the opposite effects. Mechanistically, TP53TG1 could directly bind to microRNA (miR)‐96 and effectively function as a sponge for miR‐96, thus antagonizing the functions of miR‐96 and leading to derepression of its endogenous target KRAS, which is a core oncogene in the initiation and maintenance of PDAC. Taken together, these observations imply that TP53TG1 contributes to the growth and progression of PDAC by acting as a competing endogenous RNA (ceRNA) to competitively bind to miR‐96 and regulate KRAS expression, which highlights the importance of the complicated miRNA‐lncRNA network in modulating the progression of PDAC.

Intrinsic and acquired resistance of cancer to radio-and chemotherapy is one of the major challenges in the treatment of esophageal squamous cell carcinoma (ESCC). Elevated reactive oxygen species (ROS) play an important role in the resistance to cisplatin in ESCCs. Super dismutase [Mn], mitochondrial (SOD-2), an important primary antioxidant enzyme located in mitochondria, could regulate ROS production. Our previous study showed that tumor necrosis factor-α (TNF-α)-mediated SOD-2 through NF-κB was involved in epithelial-mesenchymal transition and migration in A549 cells. Therefore, the present study aimed to identify if TNF-α mediated SOD-2 upregulation is involved in cisplatin resistance in ESCC. It was identified that a higher expression of SOD-2 in human ESCC samples was associated with TNF-α expression and poor overall survival in patients with ESCC, suggesting that SOD-2 may act as an oncogene in ESCC. To further confirm if TNF-α could upregulate SOD-2 to contribute to cell proliferation, the human ESCC cell line Eca-109 was treated with TNF-α in vitro. TNF-α could upregulate SOD-2 and induce cell proliferation in Eca109 cells, while blocking SOD-2 using small interfering RNA (siRNA) inhibited TNF-α-induced cell proliferation. Upregulation of SOD-2 by TNF-α was inhibited by blocking the NF-κB pathway, which suggested that SOD-2 by TNF-α/NF-κB contributes to cell proliferation in Eca109 cells. Furthermore, it was observed that TNF-α could induce cisplatin resistance in Eca109 cells, while transfection with SOD-2 siRNA could significantly increase the chemosensitivity of ESCC to cisplatin. Therefore, the present results suggested that SOD-2 may serve as an oncogene, and the upregulation of SOD-2 by TNF-α/NF-κB may contribute to cisplatin resistance in ESCC.