Protein tyrosine kinase 6 is associated with nasopharyngeal carcinoma poor prognosis and metastasis

BACKGROUND: The aim of this study was to analyze the expression of protein tyrosine kinase 6 (PTK6) in nasopharyngeal carcinoma (NPC) samples, and to identify whether PTK6 can serve as a biomarker for the diagnosis and prognosis of NPC. METHODS: We used quantitative RT-PCR and Western blotting analysis to detect mRNA and protein expression of PTK6 in NPC cell lines and immortalized nasopharyngeal epithelial cell lines. 31 NPC and 16 non-tumorous nasopharyngeal mucosa biopsies were collected to detect the difference in the expression of mRNA level of PTK6 by quantitative RT-PCR. We also collected 178 NPC and 10 normal nasopharyngeal epithelial cases with clinical follow-up data to investigate the expression of PTK6 by immunohistochemistry staining (IHC). PTK6 overexpression on cell growth and colony formation ability were measured by the method of cell proliferation assay and colony formation assay. RESULTS: The expression of PTK6 was higher in most of NPC cell lines at both mRNA and protein levels than in immortalized nasopharyngeal epithelial cell lines (NPECs) induced by Bmi-1 (Bmi-1/NPEC1, and Bmi-1/NPEC2). The mRNA level of PTK6 was high in NPC biopsies compared to non-tumorous nasopharyngeal mucosa biopsies. IHC results showed the expression of PTK6 was significantly correlated to tumor size (P<0.001), clinical stage (P<0.001), and metastasis (P=0.016). The patients with high-expression of PTK6 had a significantly poor prognosis compared to those of low-expression (47.8% versus 80.0%, P<0.001), especially in the patients at the advanced stages (42.2% versus 79.1%, P<0.001). Multivariate analysis indicated that the level of PTK6 expression was an independent prognostic factor for the overall survival of patients with NPC (P <0.001). Overexpression of PTK6 in HNE1 cells enhanced the ability of cell proliferation and colony formation. CONCLUSIONS: Our results suggest that high-expression of PTK6 is an independent factor for NPC patients and it might serve as a potential prognostic biomarker for patients with NPC

Absence of oxygen effect on microbial structure and methane production during drying and rewetting events

Natural environments with frequent drainage experience drying and rewetting events that impose fluctuations in water availability and oxygen exposure. These relatively dramatic cycles profoundly impact microbial activity in the environment and subsequent emissions of methane and carbon dioxide. In this study, we mimicked drying and rewetting events by submitting methanogenic communities from strictly anaerobic environments (anaerobic digestors) with different phylogenetic structures to consecutive desiccation events under aerobic (air) and anaerobic (nitrogen) conditions followed by rewetting. We showed that methane production quickly recovered after each rewetting, and surprisingly, no significant difference was observed between the effects of the aerobic or anaerobic desiccation events. There was a slight change in the microbial community structure and a decrease in methane production rates after consecutive drying and rewetting, which can be attributed to a depletion of the pool of available organic matter or the inhibition of the methanogenic communities. These observations indicate that in comparison to the drying and rewetting events or oxygen exposure, the initial phylogenetic structure and the organic matter quantity and quality exhibited a stronger influence on the methanogenic communities and overall microbial community responses. These results change the current paradigm of the sensitivity of strict anaerobic microorganisms to oxygen exposure

Searching for Black Hole Candidates by LAMOST and ASAS-SN

Most dynamically confirmed stellar-mass black holes (BHs) and their candidates were originally selected from X-ray outbursts. In the present work, we search for BH candidates in the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) survey using the spectra along with photometry from the All Sky Automated Survey for SuperNovae (ASAS-SN), where the orbital period of the binary may be revealed by the periodic light curve, such as the ellipsoidal modulation type. Our sample consists of nine binaries, where each source contains a giant star with large radial velocity variation (ΔV_R ≳ 70 km s^(-1)) and periods known from light curves. We focus on the nine sources with long periods (T_(ph) > 5 days) and evaluate the mass M_2 of the optically invisible companion. Since the observed ΔV_R from only a few repeating spectroscopic observations is a lower limit of the real amplitude, the real mass M_2 can be significantly higher than the current evaluation. It is likely an efficient method to place constraints on M 2 by combining ΔV_R from LAMOST and T_(ph) from ASAS-SN, particularly by the ongoing LAMOST Medium Resolution Survey

Neuropilin 1 is an entry factor that promotes EBV infection of nasopharyngeal epithelial cells

Epstein–Barr virus (EBV) is implicated as an aetiological factor in B lymphomas and nasopharyngeal carcinoma. The mechanisms of cell-free EBV infection of nasopharyngeal epithelial cells remain elusive. EBV glycoprotein B (gB) is the critical fusion protein for infection of both B and epithelial cells, and determines EBV susceptibility of non-B cells. Here we show that neuropilin 1 (NRP1) directly interacts with EBV gB23–431. Either knockdown of NRP1 or pretreatment of EBV with soluble NRP1 suppresses EBV infection. Upregulation of NRP1 by overexpression or EGF treatment enhances EBV infection. However, NRP2, the homologue of NRP1, impairs EBV infection. EBV enters nasopharyngeal epithelial cells through NRP1-facilitated internalization and fusion, and through macropinocytosis and lipid raft-dependent endocytosis. NRP1 partially mediates EBV-activated EGFR/RAS/ERK signalling, and NRP1-dependent receptor tyrosine kinase (RTK) signalling promotes EBV infection. Taken together, NRP1 is identified as an EBV entry factor that cooperatively activates RTK signalling, which subsequently promotes EBV infection in nasopharyngeal epithelial cells

Searching for Black Hole Candidates by LAMOST and ASAS-SN

Most dynamically confirmed stellar-mass black holes (BHs) and their candidates were originally selected from X-ray outbursts. In the present work, we search for BH candidates in the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) survey using the spectra along with photometry from the All Sky Automated Survey for SuperNovae (ASAS-SN), where the orbital period of the binary may be revealed by the periodic light curve, such as the ellipsoidal modulation type. Our sample consists of nine binaries, where each source contains a giant star with large radial velocity variation (ΔV_R ≳ 70 km s^(-1)) and periods known from light curves. We focus on the nine sources with long periods (T_(ph) > 5 days) and evaluate the mass M_2 of the optically invisible companion. Since the observed ΔV_R from only a few repeating spectroscopic observations is a lower limit of the real amplitude, the real mass M_2 can be significantly higher than the current evaluation. It is likely an efficient method to place constraints on M 2 by combining ΔV_R from LAMOST and T_(ph) from ASAS-SN, particularly by the ongoing LAMOST Medium Resolution Survey