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941.
Tuma MC Malikzay A Ouyang X Surguladze D Fleming J Mitelman S Camara M Finnerty B Doody J Chekler EL Kussie P Tonra JR 《Translational oncology》2010,3(5):318-325
Microtubules are a well-validated target for anticancer therapy. Molecules that bind tubulin affect dynamic instability of microtubules causing mitotic arrest of proliferating cells, leading to cell death and tumor growth inhibition. Natural antitubulin agents such as taxanes and Vinca alkaloids have been successful in the treatment of cancer; however, several limitations have encouraged the development of synthetic small molecule inhibitors of tubulin function. We have previously reported the discovery of two novel chemical series of tubulin polymerization inhibitors, triazoles (Ouyang et al. Synthesis and structure-activity relationships of 1,2,4-triazoles as a novel class of potent tubulin polymerization inhibitors. Bioorg Med Chem Lett. 2005; 15:5154-5159) and oxadiazole derivatives (Ouyang et al. Oxadiazole derivatives as a novel class of antimitotic agents: synthesis, inhibition of tubulin polymerization, and activity in tumor cell lines. Bioorg Med Chem Lett. 2006; 16:1191-1196). Here, we report on the anticancer effects of a lead oxadiazole derivative in vitro and in vivo. In vitro, IMC-038525 caused mitotic arrest at nanomolar concentrations in epidermoid carcinoma and breast tumor cells, including multidrug-resistant cells. In vivo, IMC-038525 had a desirable pharmacokinetic profile with sustained plasma levels after oral dosing. IMC-038525 reduced subcutaneous xenograft tumor growth with significantly greater efficacy than the taxane paclitaxel. At efficacious doses, IMC-038525 did not cause substantial myelosuppression or peripheral neurotoxicity, as evaluated by neutrophil counts and changes in myelination of the sciatic nerve, respectively. These data indicate that IMC-038525 is a promising candidate for further development as a chemotherapeutic agent. 相似文献
942.
N. Hao M. Yan H. Zhou H. M. Liu P. Cai P. K. Ouyang 《Applied Biochemistry and Microbiology》2010,46(6):561-566
AmtR, the master regulator of nitrogen control in Corynebacterium glutamicum, plays important roles in nitrogen metabolism. To investigate the influence of AmtR on amino acids production in C. glutamicum ATCC 13032, the amtR deletion strain C. glutamicum Q1 was constructed and cultured in modified CGXII minimal medium for 60 h. The ammonium consumption rates as well as amino
acids production of both strains cultured in modified CGXII minimal medium were determined. The amtR deletion in C. glutamicum caused an obvious growth defect in the exponential growth phase, but both strains had the same biomass in the stationary
phases. Maybe the less α-oxoglutarate was used for the tricarboxylic acid cycle to influence the growth of strains. During
12 h, the rate of ammonium consumption and the concentration of Glu, Pro, Arg and Ser were higher but Asp, Gly, He, Leu, Lys
were lower in the mutation strain. During 48 h, the Q1 had higher levels of Asp, Lys, Pro, Ala and Val, and lower levels of
Glu, Arg, Leu and Ile, compared to the wild. The more Glu was synthesized by the activated GS/GOGAT pathway in Q1, and then
the accumulation of relative amino acids (Pro, Arg and Ser) were up-regulated within 12 h growth. After 48 h growth, the amtR deletion obviously influenced accumulation of Ala, Asp and Pro. The amtR deletion could influence the growth and amino acids production, which could be useful to the production of amino acids. 相似文献
943.
Qi Ye Ximu Li Ming Yan Hou Cao Lin Xu Yueyuan Zhang Yong Chen Jian Xiong Pingkai Ouyang Hanjie Ying 《Applied microbiology and biotechnology》2010,87(2):517-525
To develop an economical industrial medium, untreated cane molasses (UCM) was tested as a carbon source for fermentation culturing
of Escherichia coli. To test the industrial application of this medium, we chose a strain co-expressing a carbonyl reductase (PsCR) and a glucose
dehydrogenase (BmGDH). Although corn steep liquor (CSL) could be used as an inexpensive nitrogen source to replace peptone,
yeast extract could not be replaced in E. coli media. In a volume of 40 ml per 1-l flask, a cell concentration of optical density (OD600) 15.1 and enzyme activities of 6.51 U/ml PsCR and 3.32 U/ml BmGDH were obtained in an optimized medium containing 25.66 g/l
yeast extract, 3.88 g/l UCM, and 7.1% (v/v) CSL. When 3.88 g/l UCM was added to the medium at 6 h in a fed-batch process, the E. coli concentration increased to OD600 of 24, and expression of both PsCR and BmGDH were twofold higher than that of a batch process. Recombinant cells from batch
or fed-batch cultures were assayed for recombinant enzyme activity by testing the reduction of ethyl 4-chloro-3-oxobutanoate
to ethyl (S)-4-chloro-3-hydroxybutanoate (CHBE). Compared to cells from batch cultures, fed-batch cultured cells showed higher recombinant
enzyme expression, producing 560 mM CHBE in the organic phase with a molar yield of 92% and an optical purity of the (S)-isomer of >99% enantiomeric excess. 相似文献
944.
945.
SR and SR-related proteins have been implicated as trans-acting factors that play an important role in splice selection and are involved at specific stages of spliceosome formation. A well-established property of SR protein splicing factors is their ability to influence selection of alternative splice sites in a concentration-dependent manner. Identification of molecules that regulate SR family protein expression is therefore of vital importance in RNA biology. Here we report that depletion of Pnn expression, a SR-related protein with functions involved in pre-mRNA splicing and mRNA export, induces reduced expression of a subset of cellular proteins, especially that of SR family proteins, including SC35, SRm300, SRp55, and SRp40, but not that of other nuclear proteins, such as p53, Mdm2, and ki67. Knocking down Pnn expression was achieved in vitro by siRNA transfection. Expression levels of SR and SR-related proteins in Pnn-depleted cells as compared to those in control cells were evaluated by immunofluorescent staining and Western blot with specific antibodies. In addition, we also demonstrate that loss of Pnn expression could modulate splice site selection of model reporter gene in vivo. Our finding is significant in terms of regulation of SR protein cellular concentration because it reveals that Pnn may play a general role in the control of the cellular amount of family SR proteins through down-regulation of its own expression, thereby providing us with a better understanding of the cellular mechanism by which Pnn fulfills its biological function. 相似文献
946.
947.
The Na(+)-driven Cl(-)/HCO(3)(-) exchanger (NCBE) plays an important role in the regulation of intracellular pH (pH(i)). We previously identified two variants of NCBE from rat brain of which the variant with a carboxyterminal PSD-95/Dlg/ZO-1 (PDZ) motif (rb2NCBE) colocalized with the actin cytoskeleton. Increased rb2NCBE activity by PKA inhibition and reduction by forskolin and cAMP agonist suggest PKA regulation of NCBE. Disruption of actin filaments also decreased rb2NCBE activity. EBP50 and FLAG-rb2NCBE were reciprocally co-immunoprecipitated from rb2NCBE transfected cells. It is concluded that NCBE activity is inhibited by PKA and depends on the integrity of the actin cytoskeleton within a multiprotein complex at the plasma membrane. 相似文献
948.
Thyroid hormone-induced cardiac hypertrophy is similar to that observed in physiological hypertrophy, which is associated with high cardiac contractility and increased alpha-myosin heavy chain (alpha-MHC, the high ATPase activity isoform) expression. In contrast, angiotensin II (Ang II) induces an increase in myocardial mass with a compromised contractility accompanied by a shift from alpha-MHC to the fetal isoform beta-MHC (the low ATPase activity isoform), which is considered as a pathological hypertrophy and inevitably leads to the development of heart failure. The present study is designed to assess the effect of thyroid hormone on angiotensin II-induced hypertrophic growth of cardiomyocytes in vitro. Cardiomyocytes were prepared from hearts of neonatal Wistar rats. The effects of Ang II and 3,3',5-triiodo-thyronine (T3) on incorporations of [3H]-thymine and [3H]-leucine, MHC isoform mRNA expression, PKC activity, and PKC isoform protein expression were studied. Ang II enhanced [3H]-leucine incorporation, beta-MHC mRNA expression, PKC activity, and PKCepsilon expression and inhibited alpha-MHC mRNA expression in cardiomyocytes. T3 treatment prevented Ang II-induced increases in PKC activity, PKCepsilon, and beta-MHC mRNA overexpression and favored alpha-MHC mRNA expression. Thyroid hormone appears to be able to reprogram gene expression in Ang II-induced cardiac hypertrophy, and a PKC signal pathway may be involved in such remodeling process. 相似文献
949.
950.
Borghei A Ouyang YB Westmuckett AD Marcello MR Landel CP Evans JP Moore KL 《The Journal of biological chemistry》2006,281(14):9423-9431
Tyrosine O-sulfation is a post-translational modification mediated by one of two Golgi tyrosylprotein sulfotransferases (TPST-1 and -2) expressed in all mammalian cells. Tyrosine sulfation plays an important role in the function of some known TPST substrates by enhancing protein-protein interactions. To explore the role of these enzymes in vivo and gain insight into other potential TPST substrates, TPST-2-deficient mice were generated by targeted disruption of the Tpst2 gene. Tpst2(+/-) mice appear normal and, when interbred, yield litters of normal size with a Mendelian distribution of the targeted mutation. Tpst2(-/-) mice have moderately delayed growth but appear healthy and attain normal body weight by 10 weeks of age. In contrast to Tpst1(-/-) males that have normal fertility, Tpst2(-/-) males are infertile. Tpst2(-/-) sperm are normal in number, morphology, and motility in normal media and appear to capacitate and undergo acrosomal exocytosis normally. However, they are severely defective in their motility in viscous media and in their ability to fertilize zona pellucida-intact eggs. Adhesion of Tpst2(-/-) sperm to the egg plasma membrane is reduced compared with wild type sperm, but sperm-egg fusion is similar or even increased. These data strongly suggest that tyrosine sulfation of unidentified substrate(s) play a crucial role in these processes and document for the first time the critical importance of post-translational tyrosine sulfation in male fertility. 相似文献