Overexpression of phosphatase regenerating liver 3 in oesophageal squamous cell carcinoma associated with metastasis and its comparison with phosphatase regenerating liver 1

Expression of PRL3 (phosphatase of regenerating liver 3) protein was examined with immunohistochemistry in 60 cases of ESCC (oesophageal squamous cell carcinoma) with matched lymph node metastasis (n = 40) and 6 cases of oesophageal adenocarcinoma. Its associations with PRL1 and clinicopathological parameters were analysed. The results showed the frequency of PRL3 protein expression was significantly higher in ESCC (39/60, 65%) than in normal oesophageal mucosa (0/20, P < 0.001); higher in ESCC with lymph node metastasis (30/40, 75%) than in ESCC without lymph node metastasis (9/20, P = 0.022), as well as higher in metastatic ESCC in lymph node (38/40, 95%) than in the primary ESCC (39/60, 65%, P < 0.001). PRL3 was expressed in 1 out of 6 oesophageal adenocarcinomas, but showed no nuclear staining of PRL1. Expression of PRL3 protein was positively associated with the grade and partially with the stage of ESCC. These results suggest that expression of PRL3 protein may be involved in the metastasis of ESCC and serve as a biomarker for prediction of ESCC metastasis.     

cis-Clerodane diterpenoids from the Chinese liverwort Scapania parva Steph.

Three undescribed cis-clerodane lactones, scapanialides A–C (1–3), and a new cis-clerodane furano-diterpenoid, scaparvin F (4), were isolated from the Chinese liverwort Scapania parva Steph. Scapanialide B (2) is the first cis-clerodane diterpenoid with a bicyclo[5.4.0]undecane skeleton from liverworts. Their structures including the absolute configurations were determined by extensive analysis of multidimensional NMR spectroscopy and TDDFT CD calculations, together with crystal X-ray diffraction measurements. The cytotoxicity of compounds 1–4 was preliminary tested against the Hela and MCF-7 cell lines.     

Secondary metabolites from the liverwort Heteroscyphus coalitus

A new dihydroisocoumarin derivative, R-(?)-heteroscyphide (1), together with three known terpenoid derivatives (2–4), were isolated from the liverwort Heteroscyphus coalitus. Their structures were elucidated by spectroscopic methods and the biogenetic pathway of compound 1 was proposed. Cytotoxic test revealed that they exhibited moderate inhibitory activity to three human tumor cell lines.     

Expressions of p53, c-MYC, BCL-2 and apoptotic index in human osteosarcoma and their correlations with prognosis of patients

Background: Nowadays it remains a controversial issue whether a correlation exists between the apoptosis rate of tumor tissue and the prognosis of the patients. The aim of the study is to investigate the relationships of apoptotic genes and apoptotic index of osteosarcoma tissue to prognosis of the patients, meanwhile to explore the valid prognostic biomarkers of osteosarcoma that will enhance efficacy of clinical treatments for osteosarcoma. Methods: In our studies, the immunohistochemical ABC and terminal DNA breakpoints in situ 3-hydroxy end labeling (TUNEL) techniques were used to detect the expressions of p53, c-MYC, BCL-2 and apoptotic index in 56 osteosarcoma specimens. The relationships between apoptotic genes expression and apoptotic index in osteosarcoma tissue and their correlations with pathologic classification and prognosis of osteosarcoma cases were analyzed. Results: We found that the expressions of p53, c-MYC, and BCL-2 were negatively correlated with apoptotic index of osteosarcoma tissue, were not correlated with pathological types of osteosarcoma, and were closely related to prognosis of the patients. Moreover, apoptotic index of osteosarcoma tissue was positively correlated with the long term survival of the patients. Conclusion: We concluded that the expressions of p53, c-MYC, BCL-2 protein and apoptotic index could be used as potential biomarks for predicting the progression and prognosis of osteosarcoma, and for optimizing clinical treatments.     

Identification and functional analysis of phosphorylation residues of the Arabidopsis BOTRYTIS-INDUCED KINASE1

Arabidopsis BOTRYTIS-INDUCED KINASE1 (BIK1) is a receptor-like cytoplasmic kinase acting early in multiple signaling pathways important for plant growth and innate immunity. It is known to form a signaling complex with a cell-surface receptor FLS2 and a co-receptor kinase BAK1 to transduce signals upon perception of pathogen-associated molecular patterns (PAMPs). Although site-specifi c phosphorylation is speculated to mediate the activation and function of BIK1, few studies have been devoted to complete profiling of BIK1 phosphorylation residues. Here, we identified nineteen in vitro autophosphorylation sites of BIK1 including three phosphotyrosine sites, thereby proving BIK1 is a dual-specifi city kinase for the fi rst time. The kinase activity of BIK1 substitution mutants were explicitly assessed using quantitative mass spectrometry (MS). Thr-237, Thr-242 and Tyr-250 were found to most signifi cantly affect BIK1 activity in autophosphorylation and phosphorylation of BAK1 in vitro. A structural model of BIK1 was built to further illustrate the molecular functions of specifi c phosphorylation residues. We also mapped new sites of FLS2 phosphorylation by BIK1, which are different from those by BAK1. These in vitro results could provide new hypotheses for more in-depth in vivo studies leading to deeper understanding of how phosphorylation contributes to BIK1 activation and mediates downstream signaling specifi city.     

Order-disorder-order transitions mediate the activation of cholera toxin

Cholera toxin (CT) holotoxin must be activated to intoxicate host cells. This process requires the intracellular dissociation of the enzymatic CTA1 domain from the holotoxin components CTA2 and B5, followed by subsequent interaction with the host factor ADP ribosylation factor 6 (ARF6)-GTP. We report the first NMR-based solution structural data for the CT enzymatic domain (CTA1). We show that this free enzymatic domain partially unfolds at the C-terminus and binds its protein partners at both the beginning and the end of this activation process. Deviations from random coil chemical shifts (Δδ_coil) indicate helix formation in the activation loop, which is essential to open the toxin's active site and occurs prior to its association with human protein ARF6. We performed NMR titrations of both free CTA1 and an active CTA1:ARF6-GTP complex with NAD⁺, which revealed that the formation of the complex does not significantly enhance NAD⁺ binding. Partial unfolding of CTA1 is further illustrated by using 4,4′-bis(1-anilinonaphthalene 8-sulfonate) fluorescence as an indicator of the exposed hydrophobic character of the free enzyme, which is substantially reduced when bound to ARF6-GTP. We propose that the primary role of ARF6's allostery is to induce refolding of the C-terminus of CTA1. Thus, as a folded globular toxin complex, CTA1 escapes the chaperone and proteasomal components of the endoplasmic reticulum associated degradation pathway in the cytosol and then proceeds to ADP ribosylate its target G_sα, triggering the downstream events associated with the pathophysiology of cholera.     

A two-stage probabilistic approach to multiple-community similarity indices

SUMMARY: A traditional approach for assessing similarity among N (N > 2) communities is to use multiple pairwise comparisons. However, pairwise similarity indices do not completely characterize multiple-community similarity because the information shared by at least three communities is ignored. We propose a new and intuitive two-stage probabilistic approach, which leads to a general framework to simultaneously compare multiple communities based on abundance data. The approach is specifically used to extend the commonly used Morisita index and NESS (normalized expected species shared) index to the case of N communities. For comparing N communities, a profile of N- 1 indices is proposed to characterize similarity of species composition across communities. Based on sample abundance data, nearly unbiased estimators of the proposed indices and their variances are obtained. These generalized NESS and Morisita indices are applied to comparison of three size classes of plant data (seedling, saplings, and trees) within old-growth and secondary rain forest plots in Costa Rica.     

Discovery and biochemical characterization of selective ATP competitive inhibitors of the human mitotic kinesin KSP

The kinesin spindle protein (KSP, also known as Eg5) is essential for the proper separation of spindle poles during mitosis, and inhibition results in mitotic arrest and the formation of characteristic monoaster spindles. Several distinct classes of KSP inhibitors have been described previously in the public and patent literature. However, most appear to share a common induced-fit allosteric binding site, suggesting a common mechanism of inhibition. In a high-throughput screen for inhibitors of KSP, a novel class of thiazole-containing inhibitors was identified. Unlike the previously described allosteric KSP inhibitors, the thiazoles described here show ATP competitive kinetic behavior, consistent with binding within the nucleotide binding pocket. Although they bind to a pocket that is highly conserved across kinesins, these molecules exhibit significant selectivity for KSP over other kinesins and other ATP-utilizing enzymes. Several of these compounds are active in cells and produce a phenotype similar to that observed with previously published allosteric inhibitors of KSP.