Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0178874 (tumor progression)
 40,807 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Previously, we have linked prolonged intense mitogen-activated protein kinase (MAP kinase; MAPK) signaling in hepatocytes to increased expression of p21(Cip-1/WAF1/MDA6) (p21) and p16(INK4a) (p16), that leads to a p21-dependent growth arrest. In this study, we investigated the impact of hepatitis B virus X protein (pX) expression on MAPK-modulated cell cycle progression in primary mouse hepatocytes. In hepatocytes, expression of pX enhanced protein levels of p21 and p27, but not of p16. The elevated levels of p21 and p27 correlated with reduced DNA synthesis in wild-type (+/+) hepatocytes and with a weak stimulation of DNA synthesis in p21 null (-/-) cells. Antisense p27 messenger RNA (mRNA) (p27as) increased DNA synthesis in +/+ and p21 -/- cells, and pX blunted this effect in +/+ cells. In p21 -/- cells, however, p27as permitted pX to further stimulate DNA synthesis. These data argue that a reduced ability to enhance expression of both p21 and p27 is required to fully reveal the growth-potentiating properties of pX. This finding also implies that depending on the functional status of the p21 and p27 genes, expression of pX can have 2 very different effects on hepatocyte proliferation. Prolonged intense MAPK signaling reduced DNA synthesis in +/+ cells and enhanced DNA synthesis in p21 -/- cells. The enhancement of DNA synthesis in p21 -/- cells was blocked by pX, and the effect of pX was abrogated by p27as. Furthermore in p21 -/- cells, overexpression of p16 blocked MAPK-stimulated DNA synthesis, and this effect was partially reversed by p27as. These data argue that p27 can also cooperatively interact with p16 to inhibit DNA synthesis in hepatocytes. Collectively, our findings show that reduced expression of p16, p21, and p27, which can occur during hepatocellular carcinoma, enhances the ability of MAPK signaling and pX to cause proliferation in hepatocytes. Thus loss of cyclin kinase inhibitor function may play an important role in the process of tumor progression after chronic hepatitis B virus infection.
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PMID:Hepatitis B virus X protein increases expression of p21(Cip-1/WAF1/MDA6) and p27(Kip-1) in primary mouse hepatocytes, leading to reduced cell cycle progression. 1167 61

Cyclin D1 contributes to regulate G1 progression by forming a complex with different cyclin-dependent kinases. It has oncogenic properties and is frequently overexpressed in several human tumor types. In our study, expression of cyclin D1 and Ki67, a proliferation marker, was evaluated by immunohistochemistry in human papillary superficial (pTa-pT1) bladder cancers and was correlated with p27(Kip1), p21(Waf1) and c-erbB-2 expression, with p53 gene status and protein expression, ploidy and cancer progression. Cyclin D1 expression was neither associated with tumor stage nor with tumor grade but high cyclin D1 expression (> or =25% positive nuclei) was significantly associated with p53 gene mutation (p = 0.012), low p21(Waf1) (p = 0.015) and high p27(Kip1) (p = 0.016) protein expression. Ki67 expression was not associated with tumor stage but a high proliferation index (> or =10% positive nuclei) was significantly associated with high tumor grade (p = 0.001) and with DNA aneuploidy (p = 0.005). There was no significant difference in proliferative activity between high and low cyclin D1 expressor tumors. Patients whose tumors showed high expression of cyclin D1 displayed a significantly longer disease-free survival (p < 0.001 by log-rank test). Increased Ki67 expression was significantly associated with shorter disease-free survival (p = 0.003). Both cyclin D1 (p = 0.027; RR = 1.898) and Ki67 (p = 0.047; RR = 1.932) protein expressions were independent predictors of reduced disease-free survival on a multivariate analysis that also included p27(Kip1) expression and tumor stage. The simultaneous presence of low cyclin D1, low p27(Kip1) and high Ki67 expression defined a "high-risk" group of patients who displayed a significantly increased risk of recurrence (p < 0.0001). These results suggest that evaluation of cell cycle-associated markers can help to identify high-risk patients and may affect the management of patients with papillary superficial bladder cancer.
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PMID:Cyclin D1 expression in papillary superficial bladder cancer: its association with other cell cycle-associated proteins, cell proliferation and clinical outcome. 1180 96

Tumors gradually develop as a result of a multistep acquisition of genetic alterations and ultimately emerge as selfish, intruding and metastatic cells. The genetic defects associated with the process of tumor progression affect control of proliferation, programmed cell death, cell aging, angiogenesis, escape from immune control and metastasis. Fundamental cancer research over the last thirty years has revealed a multitude of genetic alterations which specify more or less separate steps in tumor development and which are collectively responsible for the process of tumor progression. The genes affected play in normal cells a crucial role in control over cell duplication and the interaction between cells, and between cells and their direct surrounding. This is illustrated on control during the G1/S phase of the cell cycle by its ultimate regulators: cyclins and cyclin dependent kinases. These proteins not only control the transition through the G1/S phase of the cell cycle, but also serve as mediators of the interaction between cells, and between cells and their surrounding. Defaults in the regulation of these proteins are associated with tumor progression, and, therefore, serve as targets for therapy. Defaults in those genes are found in various tumor types, although some of those prevail in particular tumor types. In this review emphasis is given to the defaults that occur in head and neck cancer.
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PMID:Defects in G1-S cell cycle control in head and neck cancer: a review. 1211 44

Reduced expression of the p16 gene product (protein), an inhibitor of cyclin-D-dependent protein kinase which regulates cell cycle at the G1/S boundary, is implicated in tumor progression in various neoplasms. Hypermethylation of the p16 promoter gene has recently been suggested to be one of the reasons for the reduced protein expression. To explore the role of p16 in the biological behavior of adenoid cystic carcinomas (ACC), we investigated the immunohistochemical expression of p16 protein in 38 ACC tumors (32 primary, 3 recurrent, and 3 metastatic tumors) and the methylation status of its promoter gene. We also examined their relationships to the histological grade of malignancy. Positive reaction of p16 protein was demonstrated in the nuclei of luminar cuboidal cells in areas with tubular patterns. The reactions were reduced in the areas with solid or large cribriform patterns. The levels of p16 expression correlated with the histological grade of malignancy. Recurrent or metastatic tumors did not differ with respect to histological grades from the original tumor except for 1 case, in which p16 expression was reduced compared to the primary tumor. Methylation-specific PCR demonstrated the hypermethylation status of the p16 promoter gene in 4 of 22 primary tumors (21%), all of which showed negative or low expression of the p16 protein. The study indicated that p16 expression was reduced in ACC cases of higher histological grade of malignancy and that hypermethylation of its promoter gene may be involved in its process in some cases.
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PMID:Expression of p16 protein and hypermethylation status of its promoter gene in adenoid cystic carcinoma of the head and neck. 1262 3

The main focus of the Symposium was the fact that cell types of the innate and adaptive immune systems can have tumor-favoring as well as tumor antagonistic effects, both in a preventive and therapeutic mode. It was shown that macrophages (Mphi) and dendritic cells within a tumor exert tumor-favoring effects through the action of certain cytokines. Inflammatory reactions could favor the onset and growth of tumors. Dual immune functions were shown with CD4+ T cells and certain matrix metalloproteinase (MMP) activities favoring tumor progression and CD8+ T cells and certain heat shock proteins having antitumor action. Lack of antitumor action despite positive immune stimulation was also shown to depend on the existence of barriers to tumor infiltration by lymphocytes; remodeling of vasculature, e.g., by IFNgamma-induced cytokines like MIG and IPIO, reversed this type of impediment. Certain CXC cytokines increased tumor progression, whereas others, particularly those induced by IFNgamma, had the opposite effect; stromal-derived factor-1 and its receptor CXCR4 affected tumor propensity to metastasize in certain organs. Stromal-derived factor-1 induced MMP9, which in turn regulated the bioavailability of vascular endothelial growth factor and the cascade of its tumor-favoring effects, whereas granulocyte colony-stimulating factor decreased MMP9 and the consequences of its action. The effects of certain proinflammatory cytokines and vascular endothelial growth factor functions in angiogenesis and lymphoangiogenesis were also discussed. The favoring effects of fever-like thermal stress on the function of molecules instrumental in lymphoid cell adhesion to vessels and infiltration into sites of immune actions were described. The mechanisms involved in the development of immune memory and those conditioning Type I and CTL responses were also discussed. A number of presentations were concerned with laboratory studies aimed at developing clinical regimens with potential activity in the prevention or treatment of cancer. Prevention of Her2/neu breast cancer in transgenic mice was achieved by suitable regimens with IL12 combined with vaccines, including DNA-based vaccines administered in conjunction with electroporation. Vaccination with shared tumor antigen MUCI or cyclin B was discussed, and its clinical translation was described. The prevention of TRAMP prostate tumor in transgenic mice by anti-CTLA4 antibody plus vaccine was described, as was the translation of these regimens to the clinics. Clinical successes in melanoma patients using antimelanoma antigen antibodies in a therapeutic mode and precautions to be exerted in evaluating in vivo immune responses based on in vitro assays were emphasized. The symposium was concluded with an overall discussion focused on basic questions related to the capability of immunity to exert tumor-favoring or antitumor effects depending on conditions determined by both tumor and host functions.
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PMID:Fourteenth Annual Pezcoller Symposium: the novel dichotomy of immune interactions with tumors. 1278 11

Autocrine motility factor (AMF)/phosphoglucose isomerase (PGI; EC 5.3.1.9) is a housekeeping cytosolic enzyme that plays a key role in both glycolysis and gluconeogenesis pathways. AMF/PGI is also a multifunctional protein that displays cytokine properties, eliciting mitogenic, motogenic, and differentiation activities, and has been implicated in tumor progression and metastasis. Because little is known about AMF/PGI-dependent signaling in general and during tumorigenesis in particular, we sought to study its effect on the cell cycle. To elucidate the functional role of PGI, we stably transfected its cDNA into NIH/3T3 and BALB/c 3T3-A31 fibroblasts. Ectopic overexpression of PGI results in the acquisition of a transformed phenotype associated with an acceleration of G1 to S cell cycle transition. These were manifested by up-regulation of cyclin D1 expression and cyclin-dependent kinase activity and down-regulation of the cyclin-dependent kinase inhibitor p27Kip1. The reduced p27Kip1 protein expression level in PGI-overexpressing cells could be restored to control levels by treatment with proteasome inhibitor. PGI-overexpressing cells also exhibited elevated expression of Skp2 involved in p27Kip1 ubiquitination and elevation in the levels of retinoblastoma protein hyperphosphorylation. Thus, we may conclude that the overexpression of AMF/PGI enhances cell proliferation together with up-regulation of cyclin/cyclin-dependent kinase activities and down-regulation of p27Kip1, whereas the induction of 3T3 fibroblast transformation by PGI is regulated by the retinoblastoma protein pathway.
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PMID:Regulation of cell proliferation by autocrine motility factor/phosphoglucose isomerase signaling. 1278 64

The cell-transforming potential of 1,2-dibromoethane and folpet, two widely used agricultural pesticides that are potential sources of environmental pollution, has been previously ascribed to their promoting activity. In this study, we investigated whether BALB/c 3T3 transformation by these chemicals was associated with the deregulation of signals involved in cell-cycle progression and in cell-cycle checkpoint induction. We found that two BALB/c 3T3 cell clones transformed by in vitro medium-term (8-week) exposure to the carcinogens had a constitutive acceleration of cell transition from G(1) to S phase and an abrogation of the radiation-induced G(1)/S checkpoint. These events involved multiple signals; in particular, the inhibitors of cyclin/cyclin-dependent kinase complexes p21 and p27 were significantly down-modulated and the positive regulators of cell-cycle progression cyclin D(3) and E were up-modulated. As anticipated for cells where the G(1)/S checkpoint was abrogated, the transformed cells exhibited a significant reinforcement of the radiation-induced G(2)/M checkpoint, the only checkpoint remaining to protect genomic integrity. However, cyclin A(1) and B(1) coexpression and cyclin A(1) overexpression were found despite the G2 arrest in irradiated cells and these signals likely attenuate the G(2)/M checkpoint. These alterations to normal cell cycling may promote the emergence of both numerical and structural chromosomal abnormalities and their tolerance. Such a condition could play a key role in neoplastic transformation and be crucial in tumor progression. Furthermore, cyclin A(1) overexpression may play an autonomous role in the neoplastic transformation of BALB/c 3T3 cells, as it does in other cell types of mesenchymal origin.
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PMID:Cell-cycle deregulation in BALB/c 3T3 cells transformed by 1,2-dibromoethane and folpet pesticides. 1280 1

Cyclin E, a positive regulator of the cell cycle, controls the transition of cells from G(1) to S phase. Deregulation of the G(1)-S checkpoint contributes to uncontrolled cell division, a hallmark of cancer. We have reported previously that cyclin E is overexpressed in breast cancer and such overexpression is usually accompanied by the appearance of low molecular weight isoforms of cyclin E protein, which are not present in normal cells. Furthermore, we have shown that the expression of cyclin E low molecular weight isoforms can be used as a reliable prognostic marker for breast cancer to predict patient outcome. In this study we examined the role of cyclin E in directly activating cyclin-dependent kinase (CDK) 2. For this purpose, a series of N-terminal deleted forms of cyclin E corresponding to the low molecular weight forms detected only in cancer cells were translated in vitro and mixed with cell extracts. These tumor-specific N-terminal deleted forms of cyclin E are able to activate CDK2. Addition of cyclin E into both normal and tumor cell extracts was shown to increase the levels of CDK2 activity, along with an increase in the amount of phosphorylated CDK2. The increase in CDK2 activity was because of cyclin E binding to endogenous CDK2 in complex with endogenous cyclin E, cyclin A, or unbound CDK2. The increase in CDK2 phosphorylation was through a pathway involving cyclin-activating kinase, but addition of cyclin E to an extract containing unphosphorylated CDK2 can still lead to increase in CDK2 activity. Our data suggest that the ability of high levels of full-length and low molecular weight forms of cyclin E to activate CDK2 may be one mechanism that leads to the constitutive activation of cyclin E.CDK2 complexes leading to G(1)/S deregulation and tumor progression.
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PMID:Activation of cyclin-dependent kinase 2 by full length and low molecular weight forms of cyclin E in breast cancer cells. 1470 26

The results obtained in the Laboratory of Molecular Biology of Viruses, CRC carried out in the framework of the Human Genome program and devoted to the study of the activity of cell and viral genes in cervical cancer are summarized. DNA of human papillomaviruses persists in tumors both in episomal and integrative forms. Integration may occur in different regions of chromosomes. Viral transforming genes E6 and E7 are always present in tumor cells, while antibodies to these proteins are detected only in approximately 30% of patients. Loss of heterozygosity is detected on long and short arms of chromosome 6; some such cases are manifest already at the early stages of tumor progression, while others are typical of the late stages. Several genes that are potentially involved in tumorigenesis and are subject to hypermethylation in CpG islands were identified. Methylation of several genes is observed in approximately 30% of tumors. Tumor progression is associated with increased expression of p16ink4a, an inhibitor of cyclin-dependent kinases.
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PMID:[Interaction of viral and cellular genes in cervical tumors]. 1512 26

Expression of p16INK4A, the product of the melanoma susceptibility gene CDKN2A, has been shown to decrease in correlation with tumor progression. P16INK4A is a key regulator of cell-cycle function, and likely interacts with a variety of targets alongside cyclin-dependent kinases (CDKs). One such target is nuclear factor KB (NF-kappaB), a pleiotropic transcription factor that plays a crucial role in apoptosis, oncogenesis and cell cycle control. NF-kappaB p65 has been shown to be activated in melanoma cell lines but few studies decribe its expression in the tissue. In the present study we focused on synchronous expression of p16INK4A and NF-kappaB p65 and their functional activation in melanoma cell lines and biopsy tissue. Activation of NF-kappaB p65, as observed by electrophoretic mobility shift assay in cell lines, was correlated with expression and cellular localization of the active and inactive forms of its inhibitor, IkappaB-alpha. In melanocytic lesions, p16INK4A and NF-kappaB p65 expression were inversely correlated with levels of the nuclear component of NF-kappaB p65 increasing from nevi to primary melanomas and metastases.
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PMID:Inverse correlation between p16INK4A expression and NF-kappaB activation in melanoma progression. 1529 71


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