Role of multifunctional transcription factor TFII-I and putative tumour suppressor DBC1 in cell cycle and DNA double strand damage repair.

BACKGROUND: In multicellular organisms, precise control of cell cycle and the maintenance of genomic stability are crucial to prevent chromosomal alterations. The accurate function of the DNA damage pathway is maintained by DNA repair mechanisms including homologous recombination (HR). Herein, we show that both TFII-I and DBC1 mediate cellular mechanisms of cell-cycle regulation and DNA double strand damage repair. METHODS: Regulation of cell cycle by TFII-I and DBC1 was investigated using Trypan blue dye exclusion test, luciferase assay, and flow cytometry analysis. We also analysed the role of TFII-I and DBC1 in DNA double strand damage repair after irradiation by immunofluorescence study, clonogenicity assay, and HR assay. RESULTS: Flow cytometry analysis revealed a novel function that siRNA-mediated knockdown of endogenous DBC1 resulted in G2/M phase arrest. We also have shown that both endogenous TFII-I and DBC1 activate DNA repair mechanisms after irradiation because irradiation-induced foci formation of TFII-I-γH2AX was observed, and the depletion of endogenous TFII-I or DBC1 resulted in the inhibition of normal HR efficiency. CONCLUSION: These results reveal novel mechanisms by which TFII-I and DBC1 can modulate cellular fate by affecting cell-cycle control as well as HR pathway.

Multifunctional transcription factor TFII-I is an activator of BRCA1 function.

BACKGROUND: The TFII-I is a multifunctional transcriptional factor known to bind specifically to several DNA sequence elements and to mediate growth factor signalling. A microdeletion at the chromosomal location 7q11.23 encoding TFII-I and the related family of transcription factors may result in the onset of Williams-Beuren syndrome, an autosomal dominant genetic disorder characterised by a unique cognitive profile, diabetes, hypertension, anxiety, and craniofacial defects. Hereditary breast and ovarian cancer susceptibility gene product BRCA1 has been shown to serve as a positive regulator of SIRT1 expression by binding to the promoter region of SIRT1, but cross talk between BRCA1 and TFII-I has not been investigated to date. METHODS: A physical interaction between TFII-I and BRCA1 was explored. To determine pathophysiological function of TFII-I, its role as a transcriptional cofactor for BRCA1 was investigated. RESULTS: We found a physical interaction between the carboxyl terminus of TFII-I and the carboxyl terminus of BRCA1, also known as the BRCT domain. Endogenous TFII-I and BRCA1 form a complex in nuclei of intact cells and formation of irradiation-induced nuclear foci was observed. We also showed that the expression of TFII-I stimulates the transcriptional activation function of BRCT by a transient expression assay. The expression of TFII-I also enhanced the transcriptional activation of the SIRT1 promoter mediated by full-length BRCA1. CONCLUSION: These results revealed the intrinsic mechanism that TFII-I may modulate the cellular functions of BRCA1, and provide important implications to understand the development of breast cancer.

Inducible nitric oxide synthase and tumor necrosis factor-alpha in delayed gastric emptying and gastrointestinal transit induced by lipopolysaccharide in mice.

Gastrointestinal motility disturbances during endotoxemia are probably caused by lipopolysaccharide (LPS)-induced factors: candidates include nitric oxide (NO), tumor necrosis factor-alpha (TNF-alpha), interleukin-1ss, and interleukin-6. Flow cytometry was used to determine the effects of LPS and these factors on gastric emptying (evaluated indirectly by determining percent gastric retention; %GR) and gastrointestinal transit (GIT) in male BALB/c mice (23-28 g). NO (300 microg/mouse, N = 8) and TNF-alpha (2 microg/mouse, N = 7) increased (P < 0.01) GR and delayed GIT, mimicking the effect of LPS (50 microg/mouse). During early endotoxemia (1.5 h after LPS), inhibition of inducible NO synthase (iNOS) by a selective inhibitor, 1400 W (150 microg/mouse, N = 11), but not antibody neutralization of TNF-alpha (200 microg/mouse, N = 11), reversed the increase of GR (%GR 78.8 +/- 3.3 vs 47.2 +/- 7.5%) and the delay of GIT (geometric center 3.7 +/- 0.4 vs 5.6 +/- 0.2). During late endotoxemia (8 h after LPS), both iNOS inhibition (N = 9) and TNF-alpha neutralization (N = 9) reversed the increase of GR (%GR 33.7 +/- 2.0 vs 19.1 +/- 2.6% (1400 W) and 20.1 +/- 2.0% (anti-TNF-alpha)), but only TNF-alpha neutralization reversed the delay of GIT (geometric center 3.9 +/- 0.4 vs 5.9 +/- 0.2). These findings suggest that iNOS, but not TNF-alpha, is associated with delayed gastric emptying and GIT during early endotoxemia and that during late endotoxemia, both factors are associated with delayed gastric emptying, but only TNF-alpha is associated with delayed GIT.

Inducible nitric oxide synthase and tumor necrosis factor-alpha in delayed gastric emptying and gastrointestinal transit induced by lipopolysaccharide in mice

Gastrointestinal motility disturbances during endotoxemia are probably caused by lipopolysaccharide (LPS)-induced factors: candidates include nitric oxide (NO), tumor necrosis factor-alpha (TNF-alpha), interleukin-1ß, and interleukin-6. Flow cytometry was used to determine the effects of LPS and these factors on gastric emptying (evaluated indirectly by determining percent gastric retention; percentGR) and gastrointestinal transit (GIT) in male BALB/c mice (23-28 g). NO (300 æg/mouse, N = 8) and TNF-alpha (2 æg/mouse, N = 7) increased (P < 0.01) GR and delayed GIT, mimicking the effect of LPS (50 æg/mouse). During early endotoxemia (1.5 h after LPS), inhibition of inducible NO synthase (iNOS) by a selective inhibitor, 1400 W (150 æg/mouse, N = 11), but not antibody neutralization of TNF-alpha (200 æg/mouse, N = 11), reversed the increase of GR ( percentGR 78.8 ± 3.3 vs 47.2 ± 7.5 percent) and the delay of GIT (geometric center 3.7 ± 0.4 vs 5.6 ± 0.2). During late endotoxemia (8 h after LPS), both iNOS inhibition (N = 9) and TNF-alpha neutralization (N = 9) reversed the increase of GR ( percentGR 33.7 ± 2.0 vs 19.1 ± 2.6 percent (1400 W) and 20.1 ± 2.0 percent (anti-TNF-alpha)), but only TNF-alpha neutralization reversed the delay of GIT (geometric center 3.9 ± 0.4 vs 5.9 ± 0.2). These findings suggest that iNOS, but not TNF-alpha, is associated with delayed gastric emptying and GIT during early endotoxemia and that during late endotoxemia, both factors are associated with delayed gastric emptying, but only TNF-alpha is associated with delayed GIT.

Early endoscopic features of stomach cancer and its mode of growth.

To establish the earliest sign of stomach cancer in endoscopy and to reveal the subsequent morphologic changes of the lesion, we studied retrospectively 41 cases of stomach cancer. The eariest sign consisted of redness, small polypoid lesions, flat mucosa with slight unevenness and small depressed lesions. There was no clear correlation between the observation period and the size of cancer lesion in cases of early stomach cancer. In cases of advanced cancer, however, the observation period correlated with the size of cancer lesion to a certain extent, and the correlation between the area of cancer (Y cm2) and the observation period (X months) gave a linear equation of Y = 0.68X-3.13.

Barium enema examination using a remote controlled positive and negative contrast media inflator.

In a series of 30 patients, barium enema examination of the colon was performed via a remote controlled air and contrast media inflator. With this apparatus, introduction and elimination of air and barium into the colon can be accomplished at a freely adjustable rate of injection by remote control. Fluoroscopy time is significantly reduced and the operator is not exposed to radiation.

Mass gastric examinations of prisoners at Miyagi Prison in Japan.

Mass examinations of the stomach were carried out on 79 convicts over 40 years of age confined in the Miyagi Prison, Japan. Of the 79 subjects, 11.9% were found to need detailed examination of the stomach which disclosed gastric polyp in one case and scar from gastric ulceration in one. None was found to have carcinoma of the stomach. Complaints of symptoms were obviously more frequent with the convicts as compared with a control group. There was not, however, a significant depression in efficiency of this group examination by photofluorography, as compared with the usual gastric mass examination on general inhabitants.

Electrophoretic analysis of acid proteolytic zymogens in mucosa surrounding gastric ulcer.

Acid proteolytic zymogens contained in biopsy specimens obtained from the area surrounding peptic ulcers of the stomach were analyzed by means of agar gel electrophoresis and compared with histopathological findings. It was demonstrated that the specimens obtained from the base of ulcer contained only slow moving protease (SMP) while mucosa located near the margin of ulcer showed the pyloric mucosal type of electrophoretic pattern and increase in distance between the margin of ulcer and the site of biopsy changed the electrophoretic pattern of specimens to the fundic mucosal type. The electrophoretic findings of acid proteolytic zymogens were found to be correlated closely to histological findings, and these changes were found to distribute in a patchy form around the ulcer. It was also found that endoscopically healed scared was covered with regenerated epithelium containing parietal and chief cells of which the electrophoretic pattern of acid proteolytic zymogens was of a fundic mucosal type.