Structure, Expression, and Function of Human Pituitary Tumor-Transforming Gene (PTTG)

1999 ◽  
Vol 13 (1) ◽  
pp. 156-166 ◽  
Author(s):  
Xun Zhang ◽  
Gregory A. Horwitz ◽  
Toni R. Prezant ◽  
Alberto Valentini ◽  
Masahiro Nakashima ◽  
...  

Abstract Despite advances in characterizing the pathophysiology and genetics of pituitary tumors, molecular mechanisms of their pathogenesis are poorly understood. Recently, we isolated a transforming gene [pituitary tumor-transforming gene (PTTG)] from rat pituitary tumor cells. Here we describe the cloning of human PTTG, which is located on chromosome 5q33 and shares striking sequence homology with its rat counterpart. Northern analysis revealed PTTG expression in normal adult testis, thymus, colon, small intestine, brain, lung, and fetal liver, but most abundant levels of PTTG mRNA were observed in several carcinoma cell lines. Stable transfection of NIH 3T3 cells with human PTTG cDNA caused anchorage-independent transformation in vitro and induced in vivo tumor formation when transfectants were injected into athymic mice. Overexpression of PTTG in transfected NIH 3T3 cells also stimulated expression and secretion of basic fibroblast growth factor, a human pituitary tumor growth-regulating factor. A proline-rich region, which contains two PXXP motifs for the SH3 domain-binding site, was detected in the PTTG protein sequence. When these proline residues were changed by site-directed mutagenesis, PTTG in vitro transforming and in vivo tumor-inducing activity, as well as stimulation of basic fibroblast growth factor, was abrogated. These results indicate that human PTTG, a novel oncogene, may function through SH3-mediated signal transduction pathways and activation of growth factor(s).

Author(s):  
Eishin Yaoita ◽  
Masaaki Nameta ◽  
Yutaka Yoshida ◽  
Hidehiko Fujinaka

AbstractFibroblast growth factor 2 (FGF2) augments podocyte injury, which induces glomerulosclerosis, although the mechanisms remain obscure. In this study, we investigated the effects of FGF2 on cultured podocytes with interdigitating cell processes in rats. After 48 h incubation with FGF2 dynamic changes in the shape of primary processes and cell bodies of podocytes resulted in the loss of interdigitation, which was clearly shown by time-lapse photography. FGF2 reduced the gene expressions of constituents of the slit diaphragm, inflections of intercellular junctions positive for nephrin, and the width of the intercellular space. Immunostaining for the proliferation marker Ki-67 was rarely seen and weakly stained in the control without FGF2, whereas intensely stained cells were frequently found in the presence of FGF2. Binucleation and cell division were also observed, although no significant increase in cell number was shown. An in vitro scratch assay revealed that FGF2 enhanced migration of podocytes. These findings show that FGF2 makes podocytes to transition from the quiescent state into the cell cycle and change their morphology due to enhanced motility, and that the culture system in this study is useful for analyzing the pathological changes of podocytes in vivo.


2018 ◽  
Vol 33 (6) ◽  
pp. 808-818 ◽  
Author(s):  
Jiankui Li ◽  
Xi Chen ◽  
Kaijian Ling ◽  
Zhiqing Liang ◽  
Huicheng Xu

Introduction and hypothesis: Pelvic support structure injury is the major cause of pelvic organ prolapse. At present, polypropylene-based filler material has been suggested as a common method to treat pelvic organ prolapse. However, it cannot functionally rehabilitate the pelvic support structure. In addition to its poor long-term efficiency, the urinary bladder matrix was the most suitable biological scaffold material for pelvic floor repair. Here, we hypothesize that anti-sca-1 monoclonal antibody and basic fibroblast growth factor were cross-linked to urinary bladder matrix to construct a two-factor bioscaffold for pelvic reconstruction. Methods Through a bispecific cross-linking reagent, sulfosuccinimidyl 4-[N-maleimidomethyl] cyclohexane-1-carboxylate (sulfo-smcc) immobilized anti-sca-1 and basic fibroblast growth factor to urinary bladder matrix. Then scanning electron microscope and plate reader were used to detect whether the anti-sca-1/basic fibroblast growth factor-urinary bladder matrix scaffold was built successfully. After that, the capacity of enriching sca-1 positive cells was measured both in vitro and in vivo. In addition, we evaluated the differentiation capacity and biocompatibility of the scaffold. Finally, western blotting was used to detect the level of fibulin-5 protein. Results The scanning electron microscope and plate reader revealed that the double-factor biological scaffold was built successfully. The scaffold could significantly enrich a large number of sca-1 positive cells both in vitro and in vivo, and obviously accelerate cells and differentiate functional tissue with good biocompatibility. Moreover, the western blotting showed that the scaffold could improve the expression of fibulin-5 protein. Conclusion The anti-sca-1/basic fibroblast growth factor-urinary bladder matrix scaffold revealed good biological properties and might serve as an ideal scaffold for pelvic reconstruction.


Endocrinology ◽  
2003 ◽  
Vol 144 (11) ◽  
pp. 4991-4998 ◽  
Author(s):  
Run Yu ◽  
Wenge Lu ◽  
Jiandong Chen ◽  
Chris J. McCabe ◽  
Shlomo Melmed

Abstract The mammalian securin, pituitary tumor-transforming gene (PTTG), is overexpressed in several tumors and transforms cells in vitro and in vivo. To test the hypothesis that PTTG overexpression causes aneuploidy, enhanced green fluorescent protein (EGFP)-tagged PTTG (PTTG-EGFP) was expressed in human H1299 cancer cells (with undetectable endogenous PTTG expression) and mitosis of individual live cells observed. Untransfected cells and cells expressing EGFP alone exhibited appropriate mitosis. PTTG-EGFP markedly prolonged prophase and metaphase, indicating that PTTG blocks progression of mitosis to anaphase. In cells that underwent apparently normal mitosis (35 of 65 cells), PTTG-EGFP was degraded about 1 min before anaphase onset. Cells that failed to degrade PTTG-EGFP exhibited asymmetrical cytokinesis without chromosome segregation (18 of 65 cells) or chromosome decondensation without cytokinesis (9 of 65 cells), resulting in appearance of a macronucleus. Fifty-one of 55 cells expressing a nondegradable mutant PTTG exhibited asymmetrical cytokinesis without chromosome segregation, and some (4 of 55) decondensed chromosomes, both resulting in macronuclear formation. During this abnormal cytokinesis, all chromosomes and spindles and both centrosomes moved to one daughter cell, suggesting potential chaos in the subsequent mitosis. In conclusion, failure of PTTG degradation or enhanced PTTG accumulation, as a consequence of overexpression, inhibits mitosis progression and chromosome segregation but does not directly affect cytokinesis, resulting in aneuploidy. These results demonstrate that PTTG induces aneuploidy in single, live, human cancer cells.


Sign in / Sign up

Export Citation Format

Share Document