Polyamine metabolism and interconversion in NIH 3T3 and ras-transfected NIH 3T3 cells

The effect of transfection of NIH 3T3 cells by the human ras (c-Ha-ras-1) oncogene on uptake, interconversion, and excretion of polyamines was studied. Uptake and interconversion of spermidine were higher in the ras-transfected cells. Acetylpolyamines were excreted into the medium by the ras-transfected cells, whereas they were retained by NIH 3T3 cells. In addition to acetylpolyamines, some unknown polyamine conjugates occurred in the ras-transfected cells.     

Prostaglandin production in cultures of BALB/3T3 and SV3T3 mouse fibroblasts.

The concentration of different prostaglandins (PG's) was determined in both cells and culture medium of growing BALB/3T3 and BALB/3T3 (3T3) cultures transformed by simian virus 40 (SV3T3). Most PG's were found in the culture medium rather than in the cells. Further, the larger PG measurements were PGE and a composite measurement of PGA and PGB. PGF was detected at lower levels. The sum of PGE and the composite measurement (PGA+PGB) was the best indication of PG production in culture. When 2-day medium collections from 3T3 and SV3T3 cells were measured by radioimmunoassay for PGs, higher concentrations of PG were detected in the media of SV3T3 cultures. This difference in PG production was not due merely to differences in cell density, since SV3T3 cells produced higher PG concentrations, even at equal cell densities. PG production for a 2-day interval was more a function of cell type than cell density.     

PIK3R3 promotes chemotherapeutic sensitivity of colorectal cancer through PIK3R3/NF-kB/TP pathway

Phosphoinositide-3-kinase regulatory subunit 3(PIK3R3) is overexpressed in different types of human cancer. We previously reported the important role of PIK3R3 in colorectal cancer (CRC). However, the prognosis effect of PIK3R3 in CRC is still remaining unclear. In this study, we explored online clinical databases to analyze the prognosis differences between higher and lower expression of PIK3R3 in CRC patients. Interestingly, we found that better disease-free survival (DFS) were occurred in patients with higher expression of PIK3R3, but there is no significant difference in overall survival (OS). For further, we showed that PIK3R3 could enhance 5-FU induced apoptosis by regulating the expression of thymmidine phosphorylase (TP). In conclusion, PIK3R3 could be considered as a predictor of 5-FU sensitivity for personalized treatment, and a therapeutic target for colorectal cancer.     

1 alpha,25-Dihydroxyvitamin D3 induces anchorage-independent growth and c-Ki-ras expression of BALB/3T3 and NIH/3T3 cells

1 alpha,25-Dihydroxyvitamin D3, a hormonally active form of vitamin D, induces anchorage-independent growth of BALB/3T3 A31-1-1 and NIH/3T3 cells with concomitant increase of their mRNA level of c-Ki-ras but not of c-Ha-ras or c-myc, through a receptor-mediated mechanism. Under the same conditions, 12-O-tetradecanoylphorbol-13-acetate did not induce anchorage-independent growth in these cell lines.     

三维医学影像诊断工作站-3dmed

本文介绍了一个我们自主开发的三维医学影像诊断工作站.系统运行于Windows NT/2000/98环境,主要包括数据接口、图像预处理、切片重组、三维重建、三维显示、虚拟内窥镜等功能.可广泛用于CT、MRI等医学图像的处理与分析,辅助医生进行临床诊断,具有很好的应用前景.     

Decreased expression of both FcγRII and FcγRIII mRNA in leukemic granulocytes

Morphologically mature granulocytes from patients with chronic myeloid leukemia exhibit a defect in internalization of heat-aggregated IgG. In this study, we investigate the status of the steady-state levels of the mRNA for the two receptors for IgG, FcγRII and FcγRIII, as a step towards understanding the molecular basis of the defect and in turn the discordant maturation of the leukemic cells. Our data show that the mRNA for both receptors is lower in the leukemic cells relative to the normal cells. This may be one of the causes for the defective endocytosis.     

The prolyl 3-hydroxylases P3H2 and P3H3 are novel targets for epigenetic silencing in breast cancer

Expression of P3H2 (Leprel1) and P3H3 (Leprel2) but not P3H1 (Leprecan) is down-regulated in breast cancer by aberrant CpG methylation in the 5′ regulatory sequences of each gene. Methylation of P3H2 appears specific to breast cancer as no methylation was detected in a range of cell lines from other epithelial cancers or from primary brain tumours or malignant melanoma. Methylation in P3H2, but not P3H3, was strongly associated with oestrogen-receptor-positive breast cancers, whereas methylation in P3H3 was associated with higher tumour grade and Nottingham Prognostic Index. Ectopic expression of P3H2 and P3H3 in cell lines with silencing of the endogenous gene results in suppression of colony growth. This is the first demonstration of epigenetic inactivation of prolyl hydroxylases in human cancer, implying that this gene family represents a novel class of tumour suppressors. The restriction of silencing in P3H2 to breast carcinomas, and its association with oestrogen-receptor-positive cases, suggests that P3H2 may be a breast-cancer-specific tumour suppressor.     

14-3-3 proteins as potential oncogenes

14-3-3 proteins are a family of highly conserved cellular proteins that play key roles in the regulation of central physiological pathways. More than 200 14-3-3 target proteins have been identified, including proteins involved in mitogenic and cell survival signaling, cell cycle control and apoptotic cell death. Importantly, the involvement of 14-3-3 proteins in the regulation of various oncogenes and tumor suppressor genes points to a potential role in human cancer. The present review summarizes current findings implicating a 14-3-3 role in cancer while discussing potential mechanisms and points of action of 14-3-3 during cancer development and progression.     

Antigenic phenotype of NIH 3T3 cell line

The antigenic phenotype of the NIH 3T3 cell line was examined by use of a panel of monoclonal antibodies and alloantisera specific for H-2 and several non-H-2 antigens. The binding of antibodies to cell surface antigens was examined by a complement-dependent microcytotoxicity test and indirect immunofluorescence quantitated by flow cytometry. The phenotype of the tested NIH 3T3 cell line was H-2q, Qa-2, Ly-6.2, Thy-1.2, Ly-23.2, and 9F 3+. The expression of H-2 antigens (Kq, Dq/Lq) was lower than that in the T-lymphocytes of the B10.Q (H-2q) strain, and the expression of Qa-2 was very low. From the Ly-6 complex, the antigen Ly-m6.2A was strongly expressed, while Ly-m.6B, Ly-m.6C, and antigens ThB and H9/25 were not detected. A monoclonal antibody specific for the nonpolymorphic antigen 9F 3 brightly stained 100% of NIH 3T3 cells. Inasmuch as the NIH 3T3 immortalized cell line was developed from outbred NIH Swiss mice, a syngeneic recipient for this cell line does not exist. However, on the basis of the determined antigenic phenotype the host most compatible to NIH 3T3 cells can be selected for in vivo experiments, where an immunocompetent recipient is required. Two inbred mouse strains identical with NIH 3T3 cells in the antigens examined in this study, B10.Q and DBA/1, are of potential use for transplantation with NIH 3T3 cells.     

Synthesis and mutagenicity of 3, 3'-dihalogenated benzidines

3, 3'- Difluorobenzidine (F₂ Bz), and 3, 3'- dibromobenzidine(Br₂Bz) were synthesized and compared with 3, 3'-dichloro-benzidine(C1₂ Bz) for ability to revert Salmonella typhimurium. The relativemutagenicities in all systems are CI₂Bz = Br₂Bz > F₂Bz >Bz. F₂Bz, CI₂Bz, and Br₂Bz are direct-acting mutagens towardsS. typhimurium strain TA98. The acetylase-deficient derivativeTA98/1, 8-DNP₆ displays no resistance to induction of mutagenesisby these compounds, in the absence of mammalian activation.With addition of hamster hepatic S-9 activation the mutagenicityof these compounds increases greatly. TA98/1, 8-DNP₆ shows someresistance to this mutagenicity. Multiple Mechanisms must existfor the genotoxicity of 3, 3'-dihalogenated benzidines.     

14-3-3蛋白功能研究进展

14—3—3蛋白在所有真核细胞中均表达，是一类高度保守的酸性蛋白家族，最新的研究在阐明14—3—3蛋白在细胞周期调控、凋亡、迁移和生长分化等方面的作用取得了很大的进展。到目前为止，已经发现14—3—3蛋白能与超过200种蛋白质相互作用，几乎参与细胞所有的重要生理过程，研究14—3—3蛋白的功能，探讨其在肿瘤发病中的可能机制，对肿瘤及相关疾病的防治具有十分重要的意义。