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g1 + arrest)

Distribution by Scientific Domains

Medical Sciences	75%

Selected Abstracts

Reduction of TIP30 correlates with poor prognosis of gastric cancer patients and its restoration drastically inhibits tumor growth and metastasis

INTERNATIONAL JOURNAL OF CANCER, Issue 3 2009
Xiaohua Li
Abstract Gastric cancer is an aggressive cancer with poor prognosis. Identification of precise prognostic marker and effective therapeutic target is important in the treatment of gastric cancer. TIP30, a newly identified tumor suppressor, appears to be involved in multiple functions including tumorigenic suppression, apoptosis induction and diminishing angiogenic properties. Here, the level of TIP30 expression was determined in gastric cancer, and the impact of its alteration on cancer biology and clinical outcome was investigated. We found that TIP30 protein was absent or reduced in gastric cancer cell lines. There was also a loss or substantial decrease of TIP30 expression in 106 cases of gastric tumors as compared with that in normal gastric mucosa (p < 0.05), which was significantly associated with inferior survival duration. In a Cox proportional hazards model, TIP30 expression independently predicted better survival (p < 0.05). We also restored TIP30 protein expression in human gastric cancer-derived cells AGS and MKN28 lacking endogenous TIP30 protein to study the effects of TIP30 expression on cell proliferation, cell kinetics, tumorigenicity and metastasis in BALB/c nude mice and found that adenoviral-mediated restoration of TIP30 expression led to downregulation of cyclin D1, Bcl-2, Bcl-xl, but to upregulation of p27, Bax, p53, caspase 3 and 9 expression, cell cycle G0/G1 arrest and apoptosis in vitro, and dramatic attenuation of tumor growth and abrogation of metastasis in animal models. Taken together, the present work revealed a novel function of TIP30, which can possibly be used as an independent prognostic factor and a potential therapeutic target for gastric cancer. © 2008 Wiley-Liss, Inc. [source]

The transcriptional programme of contact-inhibition

JOURNAL OF CELLULAR BIOCHEMISTRY, Issue 5 2010
Monika Küppers
Abstract Proliferation of non-transformed cells is regulated by cell,cell contacts, which are referred to as contact-inhibition. Vice versa, transformed cells are characterised by a loss of contact-inhibition. Despite its generally accepted importance for cell-cycle control, little is known about the intracellular signalling pathways involved in contact-inhibition. Unravelling the molecular mechanisms of contact-inhibition and its loss during tumourigenesis will be an important step towards the identification of novel target genes in tumour diagnosis and treatment. To better understand the underlying molecular mechanisms we identified the transcriptional programme of contact-inhibition in NIH3T3 fibroblast using high-density microarrays. Setting the cut off: ,1.5-fold, P,,,0.05, 853 genes and 73 cDNA sequences were differentially expressed in confluent compared to exponentially growing cultures. Importing these data into GenMAPP software revealed a comprehensive list of cell-cycle regulatory genes mediating G0/G1 arrest, which was confirmed by RT-PCR and Western blot. In a narrow analysis (cut off: ,2-fold, P,,,0.002), we found 110 transcripts to be differentially expressed representing 107 genes and 3 cDNA sequences involved, for example, in proliferation, signal transduction, transcriptional regulation, cell adhesion and communication. Interestingly, the majority of genes was upregulated indicating that contact-inhibition is not a passive state, but actively induced. Furthermore, we confirmed differential expression of eight genes by semi-quantitative RT-PCR and identified the potential tumour suppressor transforming growth factor-, (TGF-,)-1-induced clone 22 (TSC-22; tgfb1i4) as a novel protein to be induced in contact-inhibited cells. J. Cell. Biochem. 110: 1234,1243, 2010. Published 2010 Wiley-Liss, Inc. [source]

Non-steroidal anti-inflammatory drugs (NSAIDs) inhibit vascular smooth muscle cell proliferation via differential effects on the cell cycle

JOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 4 2003
Gavin Brooks
ABSTRACT Abnormal vascular smooth muscle cell (VSMC) proliferation plays an important role in the pathogenesis of both atherosclerosis and restenosis. Recent studies suggest that high-dose salicylates, in addition to inhibiting cyclooxygenase activity, exert an antiproliferative effect on VSMC growth both in-vitro and in-vivo. However, whether all non-steroidal anti-inflammatory drugs (NSAIDs) exert similar antiproliferative effects on VSMCs, and do so via a common mechanism of action, remains to be shown. In this study, we demonstrate that the NSAIDs aspirin, sodium salicylate, diclofenac, ibuprofen, indometacin and sulindac induce a dose-dependent inhibition of proliferation in rat A10 VSMCs in the absence of significant cytotoxicity. Flow cytometric analyses showed that exposure of A10 cells to diclofenac, indometacin, ibuprofen and sulindac, in the presence of the mitotic inhibitor, nocodazole, led to a significant G0/G1 arrest. In contrast, the salicylates failed to induce a significant G1 arrest since flow cytometry profiles were not significantly different from control cells. Cyclin A levels were elevated, and hyperphosphorylated p107 was present at significant levels, in salicylate-treated A10 cells, consistent with a post-G1/S block, whereas cyclin A levels were low, and hypophosphorylated p107 was the dominant form, in cells treated with other NSAIDs consistent with a G1 arrest. The ubiquitously expressed cyclin-dependent kinase (CDK) inhibitors, p21 and p27, were increased in all NSAID-treated cells. Our results suggest that diclofenac, indometacin, ibuprofen and sulindac inhibit VSMC proliferation by arresting the cell cycle in the G1 phase, whereas the growth inhibitory effect of salicylates probably affects the late S and/or G2/M phases. Irrespective of mechanism, our results suggest that NSAIDs might be of benefit in the treatment of certain vasculoproliferative disorders. [source]

Rosiglitazone Inhibits Cell Proliferation by Inducing G1 Cell Cycle Arrest and Apoptosis in ADPKD Cyst-Lining Epithelia Cells

BASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 6 2010
Yawei Liu
Many drugs inhibiting cell proliferation have been proved to be effective in slowing the disease progression in ADPKD. Recent evidence has suggested that peroxisome proliferator-activated receptor , (PPAR,) ligands have anti-neoplasm effects through inhibiting cell growth and inducing cell apoptosis in various cancer cells. In the present study, we examined the expression of PPAR, in human ADPKD kidney tissues and cyst-lining epithelial cell line, and found that the expression of PPAR, was greater in ADPKD kidney tissues and cyst-lining epithelial cell line than in normal kidney tissues and human kidney cortex (HKC) cell line. Rosiglitazone inhibited significantly proliferation of cyst-lining epithelial cells in a concentration- and time-dependent manner. These effects were diminished by GW9662, a specific PPAR, antagonist. Cell cycle analysis showed a G0/G1 arrest in human ADPKD cyst-lining epithelial cells with rosiglitazone treatment. Analysis of cell cycle regulatory proteins revealed that rosiglitazone decreased the protein levels of proliferating cell nuclear antigen, pRb, cyclin D1, cyclin D2 and Cdk4 but increased the levels of p21 and p27 in a dose-dependent manner. Rosiglitazone also induced apoptosis in cyst-lining epithelial cells, which was correlated with increased bax expression and decreased bcl-2 expression. These results suggest PPAR, agonist might serve as a promising drug for the treatment of ADPKD. [source]