Loss of clusterin both in serum and tissue correlates with the tumorigenesis of esophageal squamous cell carcinoma via proteomics approaches

AIM: To identify the differentially secreted proteins or polypeptides associated with tumorigenesis of esophageal squamous cell carcinoma (ESCC) from serum and to find potential tumor secreted biomarkers.METHODS: Proteins from human ESCC tissue and its matched adjacent normal tissue; pre-surgery and postsurgery serum; and pre-surgery and normal control serum were separated by two-dimensional electrophoresis (2-DE)to identify differentially expressed proteins. The silverstained 2-DE were scanned with digital ImageScanner and analyzed with ImageMaster 2D Elite 3.10 software. A cluster of protein spots differentially expressed were selected and identified with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). One of the differentially expressed proteins, clusterin, was downregulated in cancer tissue and pre-surgery serum, but it was reversed in post-surgery serum. The results were confirmed by semi-quantitative reverse-transcription (RT)-PCR and western blot.RESULTS: Comparisons of the protein spots identified on the 2-DE maps from human matched sera showed that some proteins were differentially expressed, with most of them showing no differences in composition, shape or density.Being analyzed by MALDI-TOF-MS and database searching,clusterin was differentially expressed and down-regulated in both cancer tissue and pre-surgery serum compared with their counterparts. The results were also validated by RTPCR and western blot.CONCLUSION: The differentially expressed clusterin may play a key role during tumorigenesis of ESCC. The 2DE-MS based proteomic approach is one of the powerful tools for discovery of secreted markers from peripheral.

Translocation of annexin I from cellular membrane to the nuclear membrane in human esophageal squamous cell carcinoma

AIM: To investigate the alteration of the annexin I subcellular localization in esophageal squarnous cell carcinoma (ESCC)and the correlation between the translocation and the tumorigenesis of ESCC.METHODS: The protein localization of annexin I was detected in both human ESCC tissues and cell line via the indirect immunofluorescence strategy.RESULTS: In the normal esophageal epithelia the annex in I was mainly located on the plasma membrane and formed a consecutive typical trammels net. Annexin I protein also expressed dispersively in cytoplasm and the nuclei without specific localization on the nuclear membrane. In esophageal cancer annexin I decreased very sharply with scattered disappearance on the cellular membrane, however it translocated and highly expressed on the nuclear membrane,which was never found in normal esophageal epithelia. In cultured esophageal cancer cell line annexin I protein was also focused on the nuclear membrane, which was consistent with the result from esophageal cancer tissues.CONCLUSION: This observation suggests that the translocation of annexin I protein in ESCC may correlate with the tumorigenesis of the esophageal cancer.

Synthesis and Photoluminescence of a Novel Iridium Complex (BuPhOXD)_2Ir(acac) with Unit of 1, 3, 4-Oxadiazole

A novel cyclometalated iridium complex with 1, 3, 4-oxadiazole moiety was synthesizedand characterized. Its UV and photoluminescent properties were studied. The strong UVabsorption intensity around 462 nm attributed to spin-forbidden triplet metal–ligand charge transferband and photoluminescence at 518 nm were observed. This indicated that achieved iridiumcomplex could be used as an efficient electrophosphorescent material.

Cx31 is assembled and trafficked to cell surface by ER-Golgi pathway and degraded by proteasomal or lysosomal pathways

Gap junctions, consisting of connexins, allow the exchange of small molecules (<1 kD) between adjacent cells, thusproviding a mechanism for synchronizing the responses of groups of cells to environmental stimuli. Connexin 31 is amember of the connexin family. Mutations on connexin 31 are associated with erythrokeratodermia variabilis, hearingimpairment and peripheral neuropathy. However, the pathological mechanism for connexin 31 mutants in these diseasesare still unknown. In this study, we analyzed the assembly, trafficking and metabolism of connexin 31 in HeLa cellsstably expressing connexin 31. Calcein transfer assay showed that calcein transfer was inhibited when cells weretreated with Brefeldin A or cytochalasin D, but not when treated with nocodazole or α-glycyrrhetinic acid, suggestingthat Golgi apparatus and actin filaments, but not microtubules, are crucial to the trafficking and assembly of connexin31, as well as the formation of gap junction intercellular communication by connexin 31. Additionally, α-glycyrrhetinicacid did not effectively inhibit gap junctional intercellular communication formed by connexin 31. Pulse-chase assayrevealed that connexin 31 had a half-life of about 6 h. Moreover, Western blotting and fluorescent staining demonstratedthat in HeLa cells stably expressing connexin 31, the amount of connexin 31 was significantly increased after these cellswere treated with proteasomal or lysosomal inhibitors. These findings indicate that connexin 31 was rapidly renewed,and possibly degraded by both proteasomal and lysosomal pathways.

A time series of filament eruptions observed by three eyes from space:from failed to successful eruptions

We present stereoscopic observations of six sequential eruptions of a filament in the active region NOAA 11045 on 2010 Feb 8, with the advantage of the STEREO twin viewpoints in combination with Earth＇s viewpoint from SOHO instruments and ground-based telescopes. The last one of the six eruptions is a coronal mass ejection, but the others are not. The flare in this successful one is more intense than in the others. Moreover, the velocity of filament material in the successful one is also the largest among them. Interestingly, all the filament velocities are found to be proportional to the power of their flares. We calculate magnetic field intensity at low altitude, the decay indexes of the external field above the filament, and the asymmetry properties of the overlying fields before and after the failed eruptions and find little difference between them, indicating the same coronal confinement exists for both the failed and successful eruptions. The results suggest that, besides the confinement of the coronal magnetic field, the energy released in the low corona should be another crucial element affecting a failed or successful filament eruption. That is, a coronal mass ejection can only be launched if the energy released exceeds some critical value, given the same initial coronal conditions.

Characterization of rtSHSp13 gene encoding a development protein involved in vesicular traffic in spermiogenesis

A cDNA, designated as rtSH3p13, was isolated from a rat testis cDNA library. It consists of 1463 bp nuclear acids,which encodes a protein of 312 amino acids and was assigned the GenBank accession number AF227439. The deduced rtSH3p13 protein is a truncated isoform of SH3p13 as a result of mRNA alternative splicing. It is mainly expressed in the rat testis, detected in spermatids at the steps 8-19 of spermiogenesis, and found around the acrosome. During postnatal development, rtSH3p13 appears on day 18 and reaches maximum on day 60. Further experimental results suggested that rtSH3p13 forms a complex with activated epidermal growth factor receptor (EGFR) and interacts with synaptojanin I. Surprisingly, similar to SH3 domain, the V region of rtSH3p13 also inhibits endocytosis in CHO cells.Our results reveal a link between an rtSH3p13-synaptojanin-clathrin complex-mediated formation of pits and the process of spermiogenesis.