Carcinoma of the uterine cervix is one of the most common malignancies among women worldwide. Human papillomaviruses (HPV) have been identified as the major etiological factor in cervical carcinogenesis. However, the time lag between HPV infection and the diagnosis of cancer indicates that multiple steps, as well as multiple factors, may be necessary for the development of cervical cancer. The development and progression of cervical carcinoma have been shown to be dependent on various genetic and epigenetic events, especially alterations in the cell cycle checkpoint machinery. In mammalian cells, control of the cell cycle is regulated by the activity of cyclin-dependent kinases (CDKs) and their essential activating coenzymes, the cyclins. Generally, CDKs, cyclins, and CDK inhibitors function within several pathways, including the p16INK4A-cyclin D1-CDK4/6-pRb-E2F, p21WAF1-p27KIP1-cyclinE-CDK2, and p14ARF-MDM2-p53 pathways. The results from several studies showed aberrant regulation of several cell cycle proteins, such as cyclin D, cyclin E, p16 INK4A, p21WAF1, and p27KIP1, as characteristic features of HPV- infected and HPV E6/E7 oncogene-expressing cervical carcinomas and their precursors. These data suggested further that interactions of viral proteins with host cellular proteins, particularly cell cycle proteins, are involved in the activation or repression of cell cycle progression in cervical carcinogenesis.
Uterine Cervical Neoplasms/*pathology ; Tumor Suppressor Protein p53/physiology ; Tumor Suppressor Protein p14ARF/physiology ; Retinoblastoma Protein/physiology ; Proto-Oncogene Proteins c-mdm2/physiology ; Humans ; Female ; E2F Transcription Factors/physiology ; Cyclin-Dependent Kinase Inhibitor p27/physiology ; Cyclin-Dependent Kinase Inhibitor p21/physiology ; Cyclin-Dependent Kinase Inhibitor p16/physiology ; Cyclin-Dependent Kinase 4/physiology ; Cyclin-Dependent Kinase 2/physiology ; Cyclin E/physiology ; Cyclin D1/physiology ; Cell Cycle/*physiology

Good progress has been made in the researches on correlating genes of breast cancer in recent years. Quite a few kinds of genes such as susceptibility gene, oncogene and tumor suppressor genes have been found with implications for diagnosis, therapy and prognosis. Abnormality of breast cancer susceptibility gene (BRCA) is of great significance, especially in the development of breast cancer.
BRCA1 Protein ; genetics ; BRCA2 Protein ; genetics ; Breast Neoplasms ; genetics ; Cyclin-Dependent Kinase Inhibitor p16 ; genetics ; Cyclin-Dependent Kinase Inhibitor p21 ; Cyclins ; genetics ; Female ; Humans ; Mutation ; Neoplasm Proteins ; genetics ; Proto-Oncogene Proteins ; genetics ; Tumor Suppressor Protein p53 ; genetics

OBJECTIVE: To investigate the methylation status of CHD5 gene promoter in bone marrow from acute myeloid leukemia (AML) patients, and the underlying mechanism for initiating the pathogenesis of AML via p19/p53/p21 pathway. METHODS: Methylation status of the CHD5 gene promoter was detected by using methylation-specific polymerase chain reaction (MSPCR) in bone marrow from AML patients, and the iron-deficiency anemia (IDA) samples were served as control. The expression of CHD5, p19, p53 and p21 was determined by real-time quantitative reverse transcriptase PCR and Western blot. RESULTS: The methylation of CHD5 gene in bone marrow from AML patients increased significantly (39.06%) as compared with control group (6.67%). The methylation of CHD5 gene significantly correlated with chromosome karyotype differentiation (P＜0.01), but did not correlate with the patient's sex, age and clinical classification (P＞0.05). The mRNA expression of CHD5 gene in AML decreased, compared with control group, the mRNA and protein expression of p19, p53 and p21 in AML with CHD5 methylation promoter decreased. CONCLUSION The hypermeltylation of CHD5 gene promoter in AML patients can lead to decrease of CHD5, p19, p53 and p21 expression levels which may reduce the inhibitory effect on proliferation of leukemia cells through the regulation of p19, p53 and p21 pathway, thus promotes the occurence of AML.
Cyclin-Dependent Kinase Inhibitor p16 ; Cyclin-Dependent Kinase Inhibitor p21 ; DNA Helicases ; DNA Methylation ; Humans ; Leukemia, Myeloid, Acute ; Nerve Tissue Proteins ; Promoter Regions, Genetic ; Tumor Suppressor Protein p53

OBJECTIVETo investigate the expression of p14(ARF), p53, mdm2 and p21(WAF/CIP1) proteins and their relationship in exocrine pancreatic carcinoma.

METHODSSpecimens of pancreatic carcinoma, adjacent non-neoplastic pancreatic tissue and pancreatic benign lesions were examined for p14(ARF), p53, mdm2 and p21(WAF/CIP1) protein expression by tissue microarray technique and immunohistochemistry.

RESULTSThe expression of p14(ARF), p53, mdm2 and p21(WAF/CIP1) proteins in pancreatic carcinoma were 35.3% (59/167), 57.5% (96/101), 64.1% (107/167) and 39.5% (66/167) respectively. The expression of p53 proteins was increased in pancreatic carcinoma (P < 0.01), while the expression of p14(ARF) and p21(WAF/CIP1) proteins was reduced (P < 0.05), as compared with that in non-neoplastic pancreatic tissue. p21(WAF/CIP1) protein expression in pancreatic carcinoma significantly correlated with the age of patients and perineural invasion (P < 0.05). p53 protein expression correlated significantly with tumor differentiation, lymph node metastasis and perineural invasion (P < 0.05). Mdm2 protein expression correlated significantly with tumor differentiation (P < 0.05), while p14(ARF) protein expression correlated significantly with the age of patients and metastasis (P < 0.05). There was also statistic correlation between the expression of these four genes (P < 0.05).

CONCLUSIONSOverexpression of p53 and mdm2 and loss of p14(ARF) and p21(WAF/CIP1) expression may contribute to the pathogenesis of pancreatic carcinoma. These proteins play a critical role in cell cycle arrest and apoptosis after DNA damage through p14(ARF)-mdm2-p53-p21(WAF/CIP1) pathway. Detection of p53 and Mdm2 protein overexpression may be useful in evaluation of the aggressiveness of pancreatic carcinoma.

Adult ; Age Factors ; Apoptosis ; Cell Cycle ; Cell Cycle Proteins ; metabolism ; Cyclin-Dependent Kinase Inhibitor p21 ; Female ; Follow-Up Studies ; Gene Expression Regulation, Neoplastic ; Humans ; Lymphatic Metastasis ; Male ; Middle Aged ; Neoplasm Invasiveness ; Nuclear Proteins ; metabolism ; Pancreatic Neoplasms ; metabolism ; pathology ; Proto-Oncogene Proteins ; metabolism ; Proto-Oncogene Proteins c-mdm2 ; Tumor Suppressor Protein p14ARF ; metabolism ; Tumor Suppressor Protein p53 ; metabolism

Hexamethylene bisacetamide (HMBA) is referred as a differentiation-inducer for the clinical treatment of acute myeloid leukemia and myelodysplastic syndrome. However, the molecular mechanism of the effects of HMBA on myeloid leukemic cells remains unknown. In this study, the effects of HMBA on cell cycle and expression of cell cycle regulatory proteins in HL-60 cell were investigated in order to explore its pharmacological mechanism. The altered distribution of cell cycle and expression of its regulatory proteins (cyclin D, cyclin E and p27) in HL-6 0 cell induced by HMBA were analyzed by flow cytometry. The effects on transcription for mRNA of CKI p15, p16 and p27 in HL-60 cell were further studied by RT-PCR. The results showed that HMBA could mainly commit HL-60 cell to G0/G1 arrest and the significantly decreased endocytic cyclin E protein and increased cyclin D/p27 protein after HMBA treatment were found. There was no expression of p15, p16 mRNA in untreated HL-60 cell and 3 mmol/L of HMBA could make them expressed after exposed for 24 h or 48 h respectively. The expression of p27 mRNA was positive and no obviously different in untreated HL-60 cells exposed for 24 h, 48 h and 72 h. These results suggested that one of the pharmacological mechanisms of HMBA was to elevate the expression of p27 and reduce the cyclin E expression as well as to activate the expression of p15, p16 gene mRNA, that arrested cell at G0/G1 and exerted its effects of anti-proliferation.
Acetamides ; pharmacology ; Antineoplastic Agents ; pharmacology ; Cell Cycle ; drug effects ; Cell Cycle Proteins ; analysis ; genetics ; Cyclin D ; Cyclin E ; analysis ; Cyclin-Dependent Kinase Inhibitor p15 ; Cyclin-Dependent Kinase Inhibitor p27 ; Cyclins ; analysis ; Genes, p16 ; HL-60 Cells ; Humans ; RNA, Messenger ; analysis ; Tumor Suppressor Proteins ; analysis ; genetics

Cellular senescence is an irreversible cell cycle arrest triggered by the activation of oncogenes or mitogenic signaling as well as the enforced expression of tumor suppressors such as p53, p16(INK4A) and promyelocytic leukemia protein (PML) in normal cells. E2F-binding protein 1 (E2FBP1), a transcription regulator for E2F, induces PML reduction and suppresses the formation of PML-nuclear bodies, whereas the down-regulation of E2FBP1 provokes the PML-dependent premature senescence in human normal fibroblasts. Here we report that the depletion of E2FBP1 induces the accumulation of PML through the Ras-dependent activation of MAP kinase signaling. The cellular levels of p16(INK4A) and p53 are elevated during premature senescence induced by depletion of E2FBP1, and the depletion of p16(INK4A), but not p53 rescued senescent cells from growth arrest. Therefore, the premature senescence induced by E2FBP1 depletion is achieved through the p16(INK4A)-Rb pathway. Similar to human normal fibroblasts, the growth inhibition induced by E2FBP1 depletion is also observed in human tumor cells with intact p16(INK4A) and Rb. These results suggest that E2FBP1 functions as a critical antagonist to the p16(INK4A)-Rb tumor suppressor machinery by regulating PML stability.
Cell Line, Tumor ; Cells, Cultured ; Cellular Senescence ; genetics ; physiology ; Cyclin-Dependent Kinase Inhibitor p16 ; antagonists & inhibitors ; genetics ; physiology ; DNA-Binding Proteins ; deficiency ; genetics ; physiology ; Down-Regulation ; Fibroblasts ; Gene Expression Regulation ; Humans ; Intranuclear Inclusion Bodies ; metabolism ; MAP Kinase Signaling System ; Nuclear Proteins ; genetics ; metabolism ; physiology ; Promyelocytic Leukemia Protein ; Protein Isoforms ; Protein Stability ; RNA Interference ; Retinoblastoma Protein ; antagonists & inhibitors ; genetics ; physiology ; Transcription Factors ; deficiency ; genetics ; metabolism ; physiology ; Transfection ; Tumor Suppressor Protein p53 ; physiology ; Tumor Suppressor Proteins ; genetics ; metabolism ; physiology ; Ubiquitination ; ras Proteins ; metabolism

Alterations of genes are known to be critical for the induction of tumorigenesis, but the mechanism of ovarian carcinogenesis is little understood and remains to be elucidated. In this study, we investigated the roles of brca1, brca2 and p53 genes in the development of ovarian cancer using conditional knockout mice generated by a Cre-loxP recombinant system. Following the application of recombinant adenovirus expressing Cre in vitro, the proliferation of ovarian surface epithelium (OSE) was increased. For instance, a significant increase in cell growth was observed in OSE cells in vitro by conditional knockout isolated from the mice bearing concurrent floxed copies of brca1 and brca2/p53. However, the proliferative effect of the ovarian cells was not observed in concurrent brca1/brca2 or p53 knockout mice in vivo, indicating that we could not observe the direct evidence of the involvement of brca1, brca2, and p53 in ovarian carcinogenesis. Since morphological changes including tumor formation were not observed in mice bearing floxed copies of concurrent brca1/brca2 or p53, the inactivation of brca1/2 or p53 is not sufficient for the induction of tumor formation. Taken together, these results suggest that the deficiency of these genes may not be involved directly in the mechanism of ovarian carcinogenesis.
Animals ; BRCA1 Protein/*genetics/metabolism ; BRCA2 Protein/*genetics/metabolism ; Cell Proliferation ; Cell Transformation, Neoplastic/*genetics ; Epithelium/*pathology ; Extracellular Matrix Proteins/genetics ; Female ; Gene Silencing ; Mice ; Mice, Knockout ; Ovarian Neoplasms/*genetics ; Protein-Lysine 6-Oxidase/genetics ; Tumor Cells, Cultured ; Tumor Suppressor Protein p53/*genetics/metabolism

OBJECTIVETo evaluate the roles of p27(kip1), p16 gene protein and proliferating cell nuclear antigen expression in nasopharyngeal carcinoma (NPC).

METHODSThe EnVision immunohistochemical method was used to detect the expression of p27(kip1), p16 gene protein and PCNA in 66 cases of non-keratinized carcinoma (NKC) and 25 cases of non-tumor nasopharyngeal tissue.

RESULTS(1) The positive expression rates of p27(kip1), p16 gene protein were 65%, 68% in NKC respectively. There were significant differences between NKC and non-tumor group (P < 0.05). (2) The expression of p27(kip1), p16 protein correlated with cranial nerve encroaching and the 5-year survival rates of the patients (P < 0.05), but had no significant correlation to lymph node metastases and clinical staging (P > 0.05). The expression of PCNA was related to clinical staging and to the patient's 5-year survival rates (P < 0.05), but not to lymph node metastases and cranial nerve encroaching (P > 0.05). (3) The positive expression of p27(kip1), p16 gene protein and PCNA were correlated.

CONCLUSIONThe results suggest that immunological labeling of p27(kip1), p16 gene protein and PCNA might be used to determine the prognosis of NKC.

Adult ; Aged ; Cell Cycle Proteins ; analysis ; Cyclin-Dependent Kinase Inhibitor p16 ; analysis ; Cyclin-Dependent Kinase Inhibitor p27 ; Female ; Humans ; Immunohistochemistry ; Male ; Middle Aged ; Nasopharyngeal Neoplasms ; chemistry ; mortality ; pathology ; Prognosis ; Proliferating Cell Nuclear Antigen ; analysis ; Tumor Suppressor Proteins ; analysis

OBJECTIVETo research the regulative effect of mica monomer granule preparation on the expression of gene associated with cancer in gastric mucosa tissue of experimental chronic atrophic gastritis (CAG) rats.

METHODTo treat experimental CAG rats using mica monomer granule preparation with three different dosage-high, moderate and low level respectively. To observe the expression changes of mutant antioncogene-p53 gene-protein, oncogene p21, antioncogene p16 and anti-apoptosis gene bcl-2 in gastric mucosa of CAG rats by two-step ways of EnVision system in immunohistochemical method.

RESULTThere was the tendency that mica monomer granule preparation with three different dosage could decrease the expression of p53 as well as p21, and mica had the obvious regulative effects on deletion of p16 and high-expression of bcl-2. It could also alleviate the inflammation of gastric mucosa and promote the regeneration of gland.

CONCLUSIONThe treatment and reversion action of mica on chronic atrophic gastritis is probably related with the regulative effect on the expression of gene associated with cancer.

Aluminum Silicates ; administration & dosage ; pharmacology ; Animals ; Cyclin-Dependent Kinase Inhibitor p16 ; metabolism ; Dose-Response Relationship, Drug ; Gastric Mucosa ; metabolism ; pathology ; Gastritis, Atrophic ; metabolism ; pathology ; Materia Medica ; administration & dosage ; pharmacology ; Oncogene Protein p21(ras) ; metabolism ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Tumor Suppressor Protein p53 ; metabolism ; Tumor Suppressor Proteins ; metabolism

OBJECTIVETo explore the feasibility and mechanism of recombinant adenovirus Ad-pl4ARF in cancer gene therapy.

METHODSThe proliferation of different liver cancer cells was assessed by morphology and trypan blue assay. Cell apoptosis was confirmed by detecting phosphatidylserine (PS) externalization with Annexin V/PI double staining. The expression of related proteins was analyzed by Western bloting. Nude mouse model bearing subcutaneous transplanted BEL7402 tumor was established to study the therapeutic ability of Ad-pl4ARF.

RESULTSAd-pl4ARF suppressed cell growth and proliferation, and promoted cell apoptosis of cancer cell lines with different genetic background. Ad-pl4ARF inhibited growth of liver cancer cells ( HepG2, BEL7402) in a dose-dependent manner. Ad-pl4ARF lead to overexpression of Bax and p21, the downstream regulating genes of p53. In the experimental therapy on nude mice bearing subcutaneous transplanted BEL7402 tumor, Ad-pl4ARF suppressed tumor growth significantly.

CONCLUSIONpl4ARF is a short gene and with powerful function, which are consistent with the requirements for tumor suppressor genes used in gene therapy. It may play an important role in gene therapy against malignancies in the future.

Adenoviridae ; genetics ; Animals ; Apoptosis ; Blotting, Western ; Carcinoma, Hepatocellular ; metabolism ; pathology ; therapy ; Cell Line, Tumor ; Cell Proliferation ; Genetic Therapy ; methods ; Humans ; Liver Neoplasms, Experimental ; metabolism ; pathology ; therapy ; Mice ; Mice, Inbred BALB C ; Mice, Nude ; Proto-Oncogene Proteins p21(ras) ; metabolism ; Recombinant Fusion Proteins ; genetics ; Transfection ; Tumor Suppressor Protein p14ARF ; genetics ; Tumor Suppressor Protein p53 ; metabolism ; Xenograft Model Antitumor Assays ; bcl-2-Associated X Protein ; metabolism