Crk II silencing down-regulates IGF-IR and inhibits migration and invasion of prostate cancer cells

Crk (C10 regulator of kinase) adaptor proteins are highly expressed in many types of human cancers and often contribute to aggressive cancer phenotypes. Crk II, a member of CRK family, has been reported to regulate cell migration and metastasis in breast cancer cells. However, its role in other cancer types has not been reported. In this study, we investigated the molecular function of Crk II in prostate cancer (PCa) cells (CWR-22rv1) in vitro and using a mouse tumor model. Results showed that Crk II knockdown by shRNA-mediated silencing (Crk II-shRNA) in the PCa cells significantly inhibited both cancer cell migration and invasion in cell culture study. Crk II-shRNA cancer cells also significantly decreased colony formation in vitro, but had no significant reduction of tumor volume after 4 weeks of cancer cell xenografting in vivo when compared to the scramble control. Interestingly, Crk II-shRNA cancer cells showed a greatly reduced level of insulin-like growth factor 1 receptor (IGF-1R) and decreased signaling of the IGF-1R/PI3K/Akt axis upon IGF-1 ligand stimulation. A close interaction between Crk II and IGF-1R was demonstrated upon co-immunoprecipitation of IGF-1R with Crk II protein. Further, treatment of cells with either proteosomal degradation or protein synthesis inhibitor showed higher proportion of ubiquitin-associated IGF-1R and faster degradation of IGF-1R in Crk II-shRNA cells in comparison with that in the control cancer cells. Taken together, these data suggest that Crk II plays an important role in the regulation of IGF-1R protein stability and affects downstream of IGF-1R signaling pathways. Therefore, targeting Crk-II can block IGF-1R growth signaling and suppress cancer cell invasion and progression.     

PLK1 与妇科肿瘤的研究进展

人类肿瘤生成过程由很多复杂环节组成,其主要现象表现为细胞分裂增殖的失调控生长。细胞分裂都必须按照正常细胞程序的每一个步骤进行才能保证机体的正常运转,细胞周期依赖分子PLK1是调节正常细胞有丝分裂、胞质分裂,以及对DNA受损伤后进行一系列反应调节的重要因子。它在细胞周期中的作用已有多位学者共同认识,当细胞失调控时检测到PLK1存在过量的表达,同时大量研究表明,人类PLK1基因不仅在多种已发现的恶性肿瘤中有此现象,而且在一些肿瘤中,它关系到这些肿瘤的发生发展及预后,被认为其可能成为一种新的肿瘤标志物,还可作为肿瘤定向分子靶向治疗中的一个有效目的基因的靶点,并且近年来对PLK1在肿瘤基因蛋白靶向治疗方面的药物研究开发已经成为学者研究的一个热点方向,该文对近年来PLK1在肿瘤生成中的作用,特别是其与妇科肿瘤关系方面的一些研究进展予以以下阐述。     

昆明山海棠对中国仓鼠V79细胞二酰基甘油含量的影响

本研究以昆明山海棠根部水抽提物(Tripterygium Hypoglaucum(Level)Hutch,THH)处理中国仓鼠V79细胞,通过检测V79细胞C-M细胞频率以及二酰基甘油(1,2-diacylgcerol,DAG)的含量测定,分析了THH诱发非整倍体与细胞醇磷酯信号通路的关系.结果指出THH能在1mg/ml、2mg/ml两个剂量上使V79细胞的DAG含量显著升高(P＜0.001),并明显的提高C-M细胞频率(P＜0.05),提示肌醇酯信号通路是介导THH诱发非整倍体的途径之一.     

THE FOUNDING OF A NEW POPULATION OF DARWIN'S FINCHES

We report the natural colonization of the small Galápagos island Daphne Major by the large ground finch (Geospiza magnirostris). Immigrants of this species were present in every year of a 22-yr study, 1973–1994. Typically they arrived after a breeding season and left at the beginning of the next one. Geospiza magnirostris bred on the island for the first time in the exceptionally wet El Niño year of 1982–1983, and bred in all subsequent years except drought years. In agreement with theoretical expectations the frequency of inbreeding was unusually high. Pronounced fluctuating asymmetry in tarsus length, together with slightly reduced breeding success of inbreeding pairs, suggests a low level of inbreeding depression. Despite this, the population increased from 5 breeding individuals in 1983 to 20 breeding individuals in 1992, and probably more than twice that number in 1993, largely through recruitment of locally born birds.     

一个Hunter综合征家系粘多糖电泳分析

CT所见肝脏肿大占据左右上腹,纠正了既往把肝左叶当做脾大的结论;B超发现前所没有报道的二尖瓣赘生物将给患者终生致残;标准品DS行双向电泳,首次发现其分离为DS1与GS2两个斑点;杂合子、患者尿GAG均出现DS1斑点,而正常人则不出现。实验显示,DS1的出现在杂合子检出和患者确诊上有重要意义。     

Role of the N-terminal region of the A chain in beta 1-bungarotoxin from the venom of Bungarus multicinctus (Taiwan-banded krait)

The N-terminal -amino groups of ₁-bungarotoxin (₁-Bgt) fromBungarus multicinctus venom were modified with trinitrobenzene sulfonic acid and the modified derivative was separated by high performance liquid chromatography. The trinitrophenylated (TNP) derivative contained two TNP groups at the -amino groups of A chain and B chain and showed a marked decrease in enzymatic activity. Methionine residues at positions 6 and 8 of the A chain were oxidized with chloramine T or cleaved with cyanogen bromide to remove the N-terminal octapeptide. Oxidation of methionine residues and removal of the N-terminal octapeptide caused a precipitous decrease in enzymatic activity, whereas antigenicity remained unchanged. The presence of dihexanoyllecithin influenced the interaction between ₁-Bgt and 8-antilinonaphthalene sulfonate (ANS) and revealed that ₁-Bgt consists of two types of ANS-binding sites, one at the substrate binding site of the A chain and the other might be at the B chain. The modified derivatives still retained their affinity for Ca²⁺ and ANS, indicating that the N-terminal region is not involved in Ca²⁺ and substrate binding. A fluorescence study revealed that the -amino group of the A chain was in the vicinity of substrate binding site and that the TNP -amino groups were in proximity to Trp-19 of the A chain. In addition, the study showed that the N-terminal region is important for stabilizing the architectural environment of Trp-19. The results, together with the proposal that Trp-19 of the A chain is involved in substrate binding, suggest that the N-terminal region of the A chain plays a crucial role in maintaining a functional active site for ₁-Bgt.     

Receptor-mediated regulation of calcium mobilization and cyclic GMP synthesis in neuroblastoma cells

In neuroblastoma N1E 115 cells, carbachol, histamine and PGE1 elevated cyclic GMP content and, induced the efflux of preloaded 45Ca2+, the release of membrane-bound Ca2+ measured by fluorescent CTC, and the increase in [Ca2+]i as measured by Quin 2 fluorescence. The time course of the responses, the absolute requirement of extracellular Ca2+, the inhibition by receptor blockers, and the concentration dependency on histamine were all similar between these responses. The observation indicates that the mobilization of Ca2+, especially the increase of [Ca2+]i, may be intimately linked to the synthesis of cyclic GMP in the cells.     

Activity of the prothoracic gland and its sensitivity to prothoracicotropic hormone in the penultimate and last-larval instar of Bombyx mori

The time course of secretion of ecdysone in vitro by the prothoracic glands of Bombyx mori was studied through the penultimate and last-larval instars. Ecdysone was produced by the glands in high amounts by the penultimate instar at 72 and 84 h while the glands in the last instar exhibited a high activity over 4 days around the time of gut purge and thereafter. The glands in the penultimate instar produced ecdysone at a low level throughout the instar before the sharp peak of activity, when they became inactive and remained so for the first 3 days of the last instar after when they regained secretory activity. Sensitivity of the glands to prothoracicotropic hormone varied in accord with the changes in their secretory activity. Inactive glands were not stimulated by 22K-prothoracicotropic hormone. In addition, glands with maximal activity in the penultimate instar were insensitive to 22K-prothoracicotropic hormone. These results suggest that the prothoracic glands in the penultimate and last-instar larvae are physiologically different.     

Immunological relationships among subunits of glutathione S-transferases A, AA, B and ligandin and hybrid formation between AA and ligandin by guanidine hydrochloride

Immunological properties of ligandin(Lig) and glutathione S-transferase(GST)-A, -AA and -B were investigated for elucidating their subunit relationships. By using either anti-Lig or -AA antibody, GST-B made a clear common precipitin line with Lig or AA in double immunodiffusion and the activity was inhibited intermediately between Lig and AA, whereas Lig and AA reacted very weakly with antibodies to each other. A hybrid between Lig and AA formed by guanidine hydrochloride treatment was identified immunochemically to be GST-B. GST-A had no immunological relationship with any of other three forms.     

1H- and13C-NMR spectroscopic studies of lipid extracts of the red algaGracilaria longa

Lipid extracts of the red algaGracilaria longa were studied by¹H- and¹³C-NMR spectroscopy. Peaks in the¹³C-NMR spectra attributable to sterols, chlorophylls and carotenoids allowed free and acylated cholesterol, chlorophylla and lutein to be identified as the most abundant components of these classes. A content of 0.5 ± 0.1 μmoles of total cholesterol/g wet alga was estimated from the¹H-NMR spectrum, which also allowed the determination of the phosphatidylcholine/total lipid molar ratio (9.5 ± 0.5%). The¹³C-NMR spectroscopic experiments provided information on the position of the double bonds on the fatty acid residues. A comparison between NMR spectra of lipid extracts obtained for wet and dried alga showed that the alga undergoes both a dramatic peroxidation and some glycolipid degradation during the drying process.