Development of BRAF V600E Mutation in NRAS Q61L Mutated Rectal Cancer.

BRAF and NRAS are oncogenes in the RAS/RAF/MEK/MAP-kinase signaling pathway. Coexistent mutations of BRAF and NRAS in a single colorectal cancer patient have always been considered mutually exclusive or at least rare. The clinical outcome of these patients remains undetermined. Herein we report a 53-year-old man harboring an NRAS Q61L mutation in his primary rectal carcinoma, who presented with a concomitant mutation of BRAF V600E in his liver metastasis biopsy 55 months after the primary CRC surgical resection. Our findings suggest that a BRAF and NRAS developed co-mutation may lead to a distinct clinicopathological progression. BRAF-mutated CRCwill not benefit from anti-RAS targeted therapy.

Curcusone D, a novel ubiquitin-proteasome pathway inhibitor via ROS-induced DUB inhibition, is synergistic with bortezomib against multiple myeloma cell growth.

BACKGROUND: Ubiquitin-proteasome pathway (UPP) plays a very important role in the degradation of proteins. Finding novel UPP inhibitors is a promising strategy for treating multiple myeloma (MM). METHODS: Ub-YFP reporter assays were used as cellular UPP models. MM cell growth, apoptosis and overall death were evaluated with the MTS assay, Annexin V/PI dual-staining flow cytometry, poly (ADP-ribose) polymerase (PARP) cleavage, and PI uptake, respectively. The mechanism of UPP inhibition was analyzed by western blotting for ubiquitin, in vitro and cellular proteasomal and deubiquitinases (DUBs) activity assays. Cellular reactive oxygen species (ROS) were measured with H2DCFDA. RESULTS: Curcusone D, identified as a novel UPP inhibitor, causes cell growth inhibition and apoptosis in MM cells. Curcusone D induced the accumulation of poly-ubiquitin-conjugated proteins but could not inhibit proteasomal activity in vitro or in cells. Interestingly, the mono-ubiquitin level and the total cellular DUB activity were significantly downregulated following curcusone D treatment. Furthermore, curcusone D could induce ROS, which were closely correlated with DUB inhibition that could be nearly completely reversed by NAC. Finally, curcusone D and the proteasomal inhibitor bortezomib showed a strong synergistic effect against MM cells. CONCLUSIONS: Curcusone D is novel UPP inhibitor that acts via the ROS-induced inhibition of DUBs to produce strong growth inhibition and apoptosis of MM cells and synergize with bortezomib. GENERAL SIGNIFICANCE: The anti-MM molecular mechanism study of curcusone D will promote combination therapies with different UPP inhibitors against MM and further support the concept of oxidative stress regulating the activity of DUBs.

A role for protein inhibitor of activated STAT1 (PIAS1) in lipogenic regulation through SUMOylation-independent suppression of liver X receptors.

Liver X receptors (LXRs) are nuclear receptors that function to modulate lipid metabolism as well as immune and inflammatory responses. Upon activation by their ligands, LXRs up-regulate a spectrum of gene transcription programs involved in cholesterol and fatty acid homeostasis. However, the mechanisms by which LXR-mediated transcriptional activation is regulated remain incompletely understood. Here, we show that PIAS1, a member of the protein inhibitor of the activated STAT family of proteins with small ubiquitin-like modifier (SUMO) E3 ligase activity, acts to suppress LXR ligand-dependent transcriptional activation of the lipogenic program in hepatocytes. We found that liver mRNA expression levels of Pias1 and Pias3 were inversely associated with those of genes involved in lipogenesis in mouse models with diet-induced or genetic obesity. Overexpression of PIAS1 in primary hepatocytes resulted in a reduction of LXR ligand-induced fatty acid synthesis and suppression of the expression of lipogenic genes, including Srebp1c and Fas. Moreover, PIAS1 was able to interact with LXRß and repress its transcriptional activity upon ligand stimulation, which did not require PIAS1-promoted SUMO modification of LXRß. In addition, PIAS1 could also interact with PGC-1ß and attenuate its association with LXRß, blunting the ability of PGC-1ß to co-activate LXRß. Importantly, PIAS1 impaired LXRß binding to its target DNA sequence. Taken together, our results suggest that PIAS1 may serve as a lipogenic regulator by negatively modulating LXRs in a SUMOylation-independent manner.

Characterization of microbial diversity and community in water flooding oil reservoirs in China.

The diversity and distribution of bacterial and archaeal communities in four different water flooding oil reservoirs with different geological properties were investigated using 16S rDNA clone library construction method. Canonical correspondence analysis was used to analyze microbial community clustering and the correlation with environmental factors. The results indicated that the diversity and abundance in the bacterial communities were significantly higher than the archaeal communities, while both of them had high similarity within the communities respectively. Phylogenetic analysis showed that of compositions of bacterial communities were distinctly different both at phylum and genus level. Proteobacteria dominated in each bacterial community, ranging from 61.35 to 75.83 %, in which α-proteobacteria and γ-proteobacteria were the main groups. In comparison to bacterial communities, the compositions of archaeal communities were similar at phylum level, while varied at genus level, and the dominant population was Methanomicrobia, ranging from 65.91 to 92.74 % in the single oil reservoir. The factor that most significantly influenced the microbial communities in these reservoirs was found to be temperature. Other environmental factors also influenced the microbial communities but not significantly. It is therefore assumed that microbial communities are formed by an accumulated effect of several factors. These results are essential for understanding ecological environment of the water flooding oil reservoirs and providing scientific guidance to the performance of MEOR technology.

[Research on population structure and distribution characteristic of indigenous microorganism in post-polymer-flooding oil reservoir].

Denaturing gradient gel electrophoresis (DGGE) method and principal component analysis (PCA) method were used to analyze the structures of microorganism population in injection wells and production wells of a post-polymer-flooding oil reservoir in Daqing oil field. The results showed that the dominant species in injection wellhead were aerobic bacteria Pseudomonas and Acinenobacter. Facultative anaerobic bacteria Enterbacter was the dominant bacteria in near area of injection wells. Bacteria detected in production wells included Thauera, Clostridia, Pseudomonas, Petrobacter and some uncultured bacteria. Methanosaeta turned out to be the only archaea detected in injection wells, which was an aceticlastic methane-producing archaeon. Archaea detected in production wells consisted of Methanomicrobium, Methanospirillum and Methanobacterium. In general, aerobic bacteria, facultative anaerobe, and strictly anaerobic bacteria distributed successively from injection wells to production wells in this block. The dominant populations of archaea were different between injection wells and production wells, while were influenced by different environments and microbial metabolism products.