BACKGROUND: Cyclin-dependent kinase inhibitors (CDKI), including p21, p27 and p57 of the KIP family, are negative regulators of cell cycle progression and potentially act as tumor suppressors. The expression of p21 is induced by tumor suppressor gene p53. Mutations of p53 are common and found in various human cancers. Thus, the function of p21 as a tumor suppressor may be not retained after p53 mutation in human cancers. The aim of our study was to evaluate the tumor suppressive activity of p21 and p53 in human gastric cancer. METHODS: One hundred and two patients who underwent surgery for gastric cancer at Chonnam National University Hospital were selected retrospectively for this study. The primary selection criteria were the availability of formalin-fixed and paraffin-embedded blocks and sufficient clinical follow-up for tumor-specific survival analysis. In this study, we examined the expression of p21 and p53 in human gastric cancer tissue by immunohisto-chemistry and the correlation between their expression and clinicopathological variables. RESULTS: p21 and p53 immunoreactivities were localized in the nuclei of carcinoma cells. Positive nuclear expression of p21 and p53 was demonstrated in 63.7 and 33.3% of cancer tissues, respectively. No apparent correlation was noted between p21 and p53 expression. Negative expression of p21 correlated with advanced stage and lymph node metastasis (p=0.028 and 0.017, respectively). Moreover, negative expression of p21 correlated with poor survival (p=0.037). Positive expression of p53 correlated with depth of tumor invasion (p=0.029). However, no significant correlation could be observed between the status of p53 expression and survival. Combined analysis of p21 and p53 status showed that p21 negative and p53 positive tumors had a poorer survival than other group tumors (p=0.026). CONCLUSION: These results suggest that the status of p21 and p53 expression may help in predicting the aggressive behavior of gastric cancer. However, further studies are warranted to clarify the impact of p53 on the function of p21 as a tumor suppressor.
Adult ; Aged ; Carcinoma/genetics/*metabolism ; Female ; Gene Expression ; Genes, p53 ; Human ; Male ; Middle Aged ; Oncogene Protein p21 (ras) /genetics/*metabolism ; Prognosis ; Protein p53/genetics/*metabolism ; Retrospective Studies ; Stomach Neoplasms/genetics/*metabolism ; Survival Analysis ; Tumor Markers, Biological/genetics/*metabolism

Rapamycin and its derivatives (rapalogs), a group of allosteric inhibitors of mammalian target of rapamycin (mTOR), have been actively tested in a variety of cancer clinical trials, and some have been approved by the Food and Drug Administration for the treatment of certain types of cancers. However, the single agent activity of these compounds in many tumor types remains modest. The mTOR axis is regulated by multiple upstream signaling pathways. Because the genes (e.g., PIK3CA, KRAS, PTEN, and LKB1) that encode key components in these signaling pathways are frequently mutated in human cancers, a subset of cancer types may be addicted to a given mutation, leading to hyperactivation of the mTOR axis. Thus, efforts have been made to demonstrate the potential impact of genetic alterations on rapalog-based or mTOR-targeted cancer therapy. This review will primarily summarize research advances in this direction.
Antibiotics, Antineoplastic ; therapeutic use ; Cell Line, Tumor ; Class I Phosphatidylinositol 3-Kinases ; Humans ; Mutation ; Neoplasms ; drug therapy ; metabolism ; PTEN Phosphohydrolase ; genetics ; metabolism ; Phosphatidylinositol 3-Kinases ; genetics ; metabolism ; Protein-Serine-Threonine Kinases ; genetics ; metabolism ; Proto-Oncogene Proteins ; genetics ; metabolism ; Proto-Oncogene Proteins p21(ras) ; Signal Transduction ; Sirolimus ; analogs & derivatives ; therapeutic use ; TOR Serine-Threonine Kinases ; antagonists & inhibitors ; metabolism ; ras Proteins ; genetics ; metabolism

Lung cancer is responsible for 29% of cancer deaths in the United States and has very low 5-year survival rates of approximately 11% in men and 15% in women. Although the early diagnosis of lung cancer may increase the survival rate with adequate treatment, advanced lung cancers are often metastasized and receive limited benefit from therapeutic regimens. As conventional treatments for lung cancer reach their limitations, researchers have attempted to discover novel drug therapies aimed at specific targets contributing to the progression of tumorigenesis. Recent advances in systems biology have enabled the molecular biology of lung carcinogenesis to be elucidated. Our understanding of the physiologic processes of tumor development provide a means to design more effective and specific drugs with less toxicity, thereby accelerating the delivery of new drug therapies to the patient's bedside.
Antineoplastic Agents ; therapeutic use ; Carcinoma, Non-Small-Cell Lung ; drug therapy ; genetics ; metabolism ; Carcinoma, Small Cell ; drug therapy ; genetics ; metabolism ; Drug Delivery Systems ; Humans ; Lung Neoplasms ; drug therapy ; genetics ; metabolism ; Molecular Targeted Therapy ; methods ; Mutation ; Protein Kinase Inhibitors ; therapeutic use ; Proto-Oncogene Proteins ; genetics ; metabolism ; Proto-Oncogene Proteins p21(ras) ; Receptor, Epidermal Growth Factor ; antagonists & inhibitors ; ras Proteins ; genetics ; metabolism

Antibodies, Monoclonal ; therapeutic use ; Antibodies, Monoclonal, Humanized ; Antineoplastic Agents ; therapeutic use ; Carcinoma, Non-Small-Cell Lung ; drug therapy ; genetics ; metabolism ; pathology ; Cetuximab ; Gene Rearrangement ; Humans ; Lung Neoplasms ; drug therapy ; genetics ; metabolism ; pathology ; Mutation ; Oncogene Proteins, Fusion ; genetics ; metabolism ; Phosphorylation ; Precision Medicine ; Proto-Oncogene Proteins ; genetics ; metabolism ; Proto-Oncogene Proteins B-raf ; genetics ; metabolism ; Proto-Oncogene Proteins p21(ras) ; Receptor Protein-Tyrosine Kinases ; genetics ; metabolism ; Receptor, Epidermal Growth Factor ; genetics ; metabolism ; ras Proteins ; genetics ; metabolism

NESCA, a newly discovered signaling adapter protein in the NGF-pathway, contains a RUN domain at its N-terminus. Here we report the crystal structure of the NESCA RUN domain determined at 2.0-Å resolution. The overall fold of the NESCA RUN domain comprises nine helices, resembling the RUN domain of RPIPx and the RUN1 domain of Rab6IP1. However, compared to the other RUN domains, the RUN domain of NESCA has significantly different surface electrostatic distributions at the putative GTPase-interacting interface. We demonstrate that the RUN domain of NESCA can bind H-Ras, a downstream signaling molecule of TrkA, with high affinity. Moreover, NESCA RUN can directly interact with TrkA. These results provide new insights into how NESCA participates in the NGF-TrkA signaling pathway.
Adaptor Proteins, Signal Transducing ; chemistry ; genetics ; metabolism ; Amino Acid Sequence ; Binding Sites ; Crystallography, X-Ray ; Gene Expression ; Humans ; Models, Molecular ; Molecular Sequence Data ; Nerve Growth Factor ; chemistry ; genetics ; metabolism ; Oncogene Protein p21(ras) ; chemistry ; genetics ; metabolism ; Protein Binding ; Protein Structure, Tertiary ; Receptor, trkA ; chemistry ; genetics ; metabolism ; Recombinant Proteins ; chemistry ; genetics ; metabolism ; Sequence Homology, Amino Acid ; Signal Transduction ; rab GTP-Binding Proteins ; chemistry

OBJECTIVETo study the function of c-myc and K-ras in tumorigenesis of ovarian cancer.

METHODSK-ras and/or c-myc cDNAs were introduced into mouse ovarian surface epithelium cells (MOSE) using recombinant Moloney retroviral vectors. The resulting MOSE cells were studied by cell proliferation assays, the ability to form colonies in soft agarose, matrigel invasion assays and tumorigenicity assays in nude mice.

RESULTSK-ras and c-myc can be easily delivered to the normal MOSE cells by recombinant retroviruses. mRNA and protein of the target genes can be detected by RT-PCR and Western blot. Cell proliferation assays showed that MOSE-Ras cells and MOSE-RM cells (MOSE-Ras/Myc) grew more rapidly than parental cells (MOSE) and MOSE-Myc cells (P <0.01). In addtition, MOSE-RM cells grew more rapidly than MOSE-Ras cells (P <0. 05). Cell colony formation assays showed that while MOSE-Ras and MOSE-RM cells can form colonies in soft-agarose, the MOSE-Myc and MOSE cells did not. Matrigel invasion assays showed that MOSE-Ras and MOSE-RM cells have invasion ability, but not MOSE-Myc ascites and the control MOSE cells. Xenograft experiments showed that MOSE-Ras and MOSE-RM cells were able to form tumors in nude mice following intraperitoneal injection. Tumors were not observed in animals injected with either MOSE-Myc or MOSE cells.

CONCLUSIONThe recombinant Moloney retroviral system is a highly efficient and convenient method for introducing and expressing foreign genes in murine surface epithelial cell cultures. In this model, expression of K-ras alone is sufficient to generate tumorigenic MOSE, however expression of c-myc in conjunction with K-ras results in cells with a higher index of malignancy. Based on the assays described in this report, expression of c-myc alone can not transform MOSE cultures although it does play a role in cooperation with K-ras.

Animals ; Blotting, Western ; Cell Movement ; Cell Proliferation ; Cell Transformation, Neoplastic ; Cells, Cultured ; Epithelial Cells ; cytology ; metabolism ; Female ; Immunohistochemistry ; Mice ; Mice, Nude ; Mice, Transgenic ; Neoplasms, Experimental ; genetics ; metabolism ; pathology ; Oncogene Protein p21(ras) ; biosynthesis ; genetics ; Ovarian Neoplasms ; genetics ; metabolism ; pathology ; Ovary ; cytology ; Proto-Oncogene Proteins c-myc ; biosynthesis ; genetics ; RNA, Messenger ; biosynthesis ; genetics ; Recombinant Proteins ; biosynthesis ; Retroviridae ; genetics ; Reverse Transcriptase Polymerase Chain Reaction ; Transfection

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

OBJECTIVETo detect the expression of prostate cancer antigen-1 (PCA-1) in prostate cancer, and to analyze the effects of downregulation of PCA-1 expression on malignant biological behavior of prostate cancer LNCaP cells, and to explore their possible molecular mechanisms.

METHODSPCA-1-siRNA and control siRNA were transfected into LNCaP cells with lipofectamine 2000. The cell cycle, proliferation and migration were determined by methyl thiazolyl tetrazolium (MTT) assay, flow cytometry and Transwell chambers, respectively. Western blotting was used to detect the expression of cyclin E, matrix metallopeptidase 9 (MMP-9) and p21. Immunohistochemistry was used to detect the expression of PCA-1 protein in 126 cases of prostate cancer and 88 cases of benign prostatic hyperplasia (BPH).

RESULTSThe positive rate of PCA-1 expression was 77.8% (98/126) in prostate cancer, and 10.2% (9/88) in BPH, and its expression was not significantly related to age, prostate specific antigen (PSA), Eastern Cooperative Oncology Group (ECOG) score (P > 0.05), and was associated with Gleason score, TNM staging and bone metastasis (P < 0.05). Downregulation of PCA-1 expression inhibited cell proliferation, arrested cell cycle at S phase and decreased cell migration of LNCaP cells. The downregulation of PCA-1 expression decreased the expression of Bcl-xl, cyclin E and MMP-9 proteins, but increased the expression of p21 proteins.

CONCLUSIONSPCA-1 may play an important role in the development of prostate cancer. The downregulation of PCA-1 expression can lead to changes in the proliferation, cell cycle and migration of prostate cancer LNCaP cells, and these effects may be associated with the decrease of Bcl-xl, cyclin E and MMP-9 proteins and increase of p21 protein.

Aged ; Aged, 80 and over ; Antigens, Neoplasm ; genetics ; metabolism ; Cell Cycle ; Cell Line, Tumor ; Cell Movement ; Cell Proliferation ; Cyclin E ; metabolism ; Down-Regulation ; Gene Expression Regulation, Neoplastic ; Humans ; Male ; Matrix Metalloproteinase 9 ; metabolism ; Middle Aged ; Neoplasm Staging ; Oncogene Proteins ; metabolism ; Prostatic Neoplasms ; metabolism ; pathology ; Proto-Oncogene Proteins p21(ras) ; metabolism ; RNA, Small Interfering ; genetics ; Transfection ; bcl-X Protein ; metabolism

OBJECTIVETo analyze immunophenotypes and gene mutations of colorectal precancerous lesions and adenocarcinoma, and to compare the difference of carcinogenetic mechanisms between the two precancerous lesions.

METHODSFifty-three cases of colorectal serrated lesions including 30 hyperplastic polyps, 20 sessile serrated adenomas (SSA) and 3 mixed polyps were collected from January 2006 to June 2012.Forty-five cases of traditional adenomas and 50 cases of colorectal adenocarcinomas were also recruited. Thirty hyperplastic polyps, 20 cases of SSA, 3 mixed polyps and 45 traditional adenomas were investigated by immunohistochemistry for the expression of DNA mismatch repair (MMR) proteins (MLH1, MSH2 and MSH6) and DNA methyltransferase MGMT. Mutations of KRAS, BRAF and PIK3CA genes in 10 cases of SSAs, 10 traditional adenomas, 1 mixed polyps and 50 colorectal adenocarcinomas were analyzed by PCR followed by direct Sanger sequencing.

RESULTS(1) Only 3 cases of hyperplastic polyps lost MLH1 expression, and none of SSAs or traditional adenomas showed loss of MLH1. The negative expression rates of MSH2, MSH6 and MGMT in hyperplastic polyps and SSA were significantly higher than those of traditional adenomas. (2) KRAS mutation was found in 5/10 cases of SSAs, 5/10 traditional adenomas and 1/1 mixed polyps. (3) Colorectal adenocarcinomas harbored the mutations of KRAS (48%, 24/50), BRAF (6%, 3/50) and PIK3CA (4%, 2/50).

CONCLUSIONSImmunophenotypic and gene mutation profiles are different between colorectal serrated lesion and traditional adenoma. Alterations of MMR and MGMT expression play important roles in the pathogenesis of "serrated neoplasm". KRAS mutation is a significant genetic change in the early phase of colorectal carcinogenesis.

Adaptor Proteins, Signal Transducing ; metabolism ; Adenocarcinoma ; genetics ; metabolism ; Adenoma ; genetics ; metabolism ; Aged ; Class I Phosphatidylinositol 3-Kinases ; Colonic Polyps ; genetics ; metabolism ; Colorectal Neoplasms ; genetics ; metabolism ; DNA Mismatch Repair ; DNA Modification Methylases ; metabolism ; DNA Repair Enzymes ; metabolism ; DNA, Neoplasm ; metabolism ; DNA-Binding Proteins ; metabolism ; Female ; Humans ; Hyperplasia ; Immunophenotyping ; Male ; Middle Aged ; MutL Protein Homolog 1 ; MutS Homolog 2 Protein ; metabolism ; Nuclear Proteins ; metabolism ; Phosphatidylinositol 3-Kinases ; genetics ; Point Mutation ; Precancerous Conditions ; genetics ; metabolism ; Proto-Oncogene Proteins ; genetics ; Proto-Oncogene Proteins B-raf ; genetics ; Proto-Oncogene Proteins p21(ras) ; Sequence Analysis, DNA ; Tumor Suppressor Proteins ; metabolism ; ras Proteins ; genetics

OBJECTIVESTo study the interaction of hepatitis virus B (HBV) and tumor suppressor p53.

METHODSPlasmid pCMVp53 was transfected or cotransfected with pCMVHBVa (wild type HBV) or PCMVHBVb (mutant type HBV) into the hepatoma cell line SMMC-7721 by lipofectamine. Apoptosis cells were labeled by annexin V-FITC and confirmed by flow cytometry. Reporter plasmids PG13-CAT or p21-luc were cotransfected respectively in each group to indicate transactivation activity of p53 and it's effect on p21 promoter. Western blot was performed to observe p53 expression in each group.

RESULTSThe group transfected by pCMVp53 alone exhibit higher luciferase activity and higher apoptosis rate, otherwise, p53 expression, enzyme activity of PG13-CAT or p21- luc and cell apoptosis rate were much higher in the group cotransfected by pCMVp53 and pCMVHBVa, but not in the other cotransfected group; HBV replication was enhanced in p53 cotransfected group.

CONCLUSIONp53 expression and effects could be enhanced by HBV and p53 had positive regulation effect on HBV replication.

Apoptosis ; Carcinoma, Hepatocellular ; genetics ; pathology ; virology ; Cell Line, Tumor ; Hepatitis B virus ; genetics ; physiology ; Humans ; Liver Neoplasms ; genetics ; pathology ; virology ; Luciferases ; metabolism ; Promoter Regions, Genetic ; Proto-Oncogene Proteins p21(ras) ; genetics ; Trans-Activators ; genetics ; Transfection ; Tumor Suppressor Protein p53 ; genetics ; metabolism ; Virus Replication