Acetylation ; Animals ; Humans ; Phosphorylation ; Tumor Suppressor Protein p53 ; chemistry ; genetics ; metabolism ; physiology

OBJECTIVETo study the effect of extraneous p53 gene with deletion of c-terminal 356 - 393 amino acids on inhibition of malignant phenotype of human lung cancer cell line.

METHODSRecombinant plasmid pEGFP-p53 (del) with codon deletion of c-terminal 37 amino acids from 393 to 356 region and pEGFP-p53 (wild type) were constructed. The human lung cancer cell line 801D served as a receipt cell had p53 deletion and mutation at 248 codon. 801D cells, having been transfected by pEGFP-p53 (wild type), pEGFP-p53 (del) or pEGFP, were selected by G418. Growing transfected cells were cloned respectively by method of dilution. Presence of extraneous gene was detected by PCR, their expression in cells was examined by fluorescence microscopy. Cloning efficiency was in vitro tested to examine the cellular proliferating ability. The xenograft in nude mice was performed and xenograft tumors were weighed one month later. Expression of GFP in tumor and transplanted cellular mass were detected by blot slices.

RESULTSpEGFP-p53 (del)-801D, pEGFP-p53-801D and pEGFP-801D were established. Extraneous p53 gene and expression of GFP were found in pEGFP-p53 (del)-801D and pEGFP-p53-801D. Inhibitory rate of colony was 99.6% for pEGFP-p53 (del)-801D and 81.0% for pEGFP-p53-801D. Inhibition of malignant proliferation of extraneous p53 (del) was higher than that of p53 (wild type) (P < 0.01). Even when inhibition of malignant proliferation extraneous pEGFP-p53 (del) was obvious, 0.2% colonies were formed, extraneous p53 and expression of GFP were observed. Animal test showed that tumor on the nude mice was positive (4/4, 4/4) in the control group (801D and pEGFP-801D), but negative (0/4, 0/4) in the experiment group [pEGFP-p53 (del) 801D and pEGFP-p53 (wild type) 801D]. Expression of GFP in the cells of cellular mass transplanted by pEGFP-p53 (del) 801D or pEGFP-p53 (wild type) 801D was observed.

CONCLUSIONIn vitro inhibitory effect of extraneous p53 gene with deletion of C-terminal 356 - 393 amino acids on malignant growth of lung cancer cell with p53 mutation or deletion at 248 codon is marked. Inhibitory action of p53 on malignant proliferation of cancer cells is heterogeneous.

Animals ; Cell Cycle ; Cell Line, Tumor ; Genes, p53 ; Humans ; Lung Neoplasms ; genetics ; pathology ; Mice ; Mutation ; Phenotype ; Structure-Activity Relationship ; Transfection ; Tumor Suppressor Protein p53 ; chemistry ; physiology

This study was carried out to predict the possible tertiary structure alterations of p53 protein after point mutation of p53 gene condon 282 in lung cancer cells based on the latest 3D structure analysis platform series of Phyre software. It was found that the p53 gene condon 282 mutation (Arg/Leu) may destabilize the H2 helix and DNA binding in the major groove by compromising the contacts of p53 protein with the beta-hairpin of DNA binding surface.
Amino Acid Sequence ; Base Sequence ; Codon ; genetics ; Humans ; Lung Neoplasms ; genetics ; pathology ; Models, Molecular ; Molecular Sequence Data ; Point Mutation ; Protein Structure, Tertiary ; Tumor Suppressor Protein p53 ; chemistry ; genetics

OBJECTIVETo study the prevalence of P53 protein expression and p53 gene mutation in laryngeal carcinoma.

METHODSUsing immunohistochemistry P53 expression was detected in 31 patients with laryngeal carcinoma. In 11 P53 negative patients,microdissection-PCR-HA technique was used to determine mutation in p53 exon 5, 6, 7, 8.

RESULTSAmong the 31 patients tested with immunostaining, the overall average positive rate was 64.5%. Positive rates for T3 and T4 tumors were 86.7% vs 43.8% in T1 and T2 tumors.The positive rate was 91.7% in those with cervical node metastasis compared with 47.4% in those without lymph node metastasis. The positive P53 immunostaining was more frequently found in poor differentiated carcinoma (87.5%) and moderate-differentiated carcinoma (66.7%),than in well differentiated carcinoma (45.5%). The abnormal exon 5 or 7 of p53 gene were detected in 2 out of 11 cases, in which P53 was negative.

CONCLUSIONP53 gene mutation is related with TNM grading and cervical lymph node metastasis in laryngeal carcinoma. P53 mutation tents to be correlated to pathologic grading.

Adult ; Aged ; Female ; Genes, p53 ; Heteroduplex Analysis ; Humans ; Immunohistochemistry ; Laryngeal Neoplasms ; chemistry ; genetics ; Male ; Middle Aged ; Mutation ; Tumor Suppressor Protein p53 ; analysis

Mutation of the p53 tumor suppressor gene has been related in the pathogenesis of numerous human and canine cancers, including breast cancers and mammary tumors. We have investigated exons 5-8 of the p53 gene for mutations in 20 spontaneous canine mammary tumors using polymerase chain reaction (PCR) with direct sequence analysis to evaluate the role of this gene in canine mammary tumorigenesis and analyzed to compare with other clinicopathological parameters including age, histology, stage, recurrence and death from tumor. Four missense (one case had two missense mutations) and one nonsense mutations were detected in 10 malignant lesions (40%), and two missense and one silent mutations were found in 10 benign mammary tumors (30%). Five of the missense mutations were located in highly conserved domains II, III, IV and V. After a follow-up period, four dogs showed a progression and three of these patients revealed death from mammary carcinoma with p53 mutation. These results demonstrated that the p53 gene mutations might be involved in the development of canine mammary tumors and contribute to the prognostic status in canine mammary carcinomas.
Animals ; Codon, Nonsense/genetics ; DNA, Neoplasm/chemistry/genetics ; Dog Diseases/*genetics ; Dogs ; Female ; Genes, p53/*genetics ; Mammary Neoplasms, Animal/*genetics ; Mutation, Missense/genetics ; Polymerase Chain Reaction/veterinary ; Sequence Analysis, DNA ; Survival Analysis ; Tumor Suppressor Protein p53/genetics

OBJECTIVETo characterize, identify and investigate the anticancer properties of two new soil fungal isolates, Emericella nidulans and Fusarium solani isolated from Wady El-Natron in Egypt against colon cancer Caco-2 (ATCC) cell line.

METHODSSoil sample was cultured and two strains were chosen for morphological and phenotypical characterization. Partial sequences of the 18s rRNA gene and the internal transcribed spacer region ITS of the two isolates were amplified by PCR. Phylogenetic tree construction and analysis of the resulted multiple sequences from the two fugal isolates were also carried out. In vitro anticancer activity of the two strains was done against colon Caco-2 cancer cell line. Reverse transcription - PCR was carried out to detect level of expression of p53 in Caco-2 cell line.

RESULTSHF.1 displayed morphological and genotypic characteristics most similar to that of Fusarium solani while HF.2 was most similar to Emericella nidulans with high similarity of 99% and 97% respectively. The multiple sequence alignment of the two fungal isolates showed that, the maximum identical conserved domains in the 18s rRNA genes were identified with the nucleotide regions of 51st to 399th base pairs, 88th to 525th base pairs respectively. While those in the ITS genes were identified with the nucleotide regions of 88th to 463rd and 51st to 274th. The two isolates showed IC50 value with (6.24±5.21) and (9.84±0.36) µg/mL) concentrations respectively at 28h. Reverse transcription - PCR indicated that these cells showed high level of expression for p53 mRNA.

CONCLUSIONSThe morphology and molecular analysis identified HF.1 and HF.2 to be Fusarium solani and Emericella nidulans; new isolates of anticancer producing fungi from Wady El-Natroon city in Egypt. Treatment with the two isolates caused P53 expression in Caco-2 cell line. These two isolates can be used as an anticancer agents.

Antineoplastic Agents ; chemistry ; pharmacology ; Caco-2 Cells ; Complex Mixtures ; chemistry ; pharmacology ; Egypt ; Emericella ; chemistry ; classification ; genetics ; isolation & purification ; Fusarium ; chemistry ; classification ; genetics ; isolation & purification ; Gene Expression ; drug effects ; Humans ; Phylogeny ; Soil Microbiology ; Tumor Suppressor Protein p53 ; genetics ; metabolism

OBJECTIVETo study the expression and significance of apoptosis-related protein p53, Bcl-2, and Bax during the development of oral squamous cell carcinoma (SCC).

METHODSThe expression was observed in 10 normal oral epithelia, 48 dysplasia epithelia and 42 SCC by immunohistochemical evaluation.

RESULTSIn normal mucosa, the positive rate of p53, Bcl-2 and Bax were 0%, 20% and 60%. In dysplasia epithelia, the positive rate of p53 is increased (P < 0.05), the positive rate of Bcl-2 and Bax remained no significant change (P > 0.05), but the positive intensity in severe dysplasia was higher than in mild group. In SCC, the positive rate of Bcl-2 increased significantly (compared with dysplasia, P < 0.05), while the expression of Bax was decreased with the increase of SCC histological grade. Further analysis showed the correlation was evident in p53 and Bax in dysplasia, and in p53 and Bcl-2 in SCC.

CONCLUSIONSIn dysplasia, p53 gene mutation results in accumulation of dysplasia cells. In SCC, the cooperation of p53, Bcl-2 and Bax results in the progression of SCC. Apoptosis genes could work either independently or cooperatively.

Apoptosis ; genetics ; Carcinoma, Squamous Cell ; chemistry ; Humans ; Immunohistochemistry ; Mouth Mucosa ; chemistry ; pathology ; Mouth Neoplasms ; chemistry ; Proto-Oncogene Proteins ; analysis ; Proto-Oncogene Proteins c-bcl-2 ; analysis ; Tumor Suppressor Protein p53 ; analysis ; bcl-2-Associated X Protein

To study the effect of the combined administration of different doses of Glycyrrhizae Radix et Rhizoma and Atractylodis Macrocephalae Rhizoma on the proliferation of DFMO-treated intestinal epithelial cells (IEC-6) and p53, p21 mRNA and protein expressions, in order to define the molecular basis for the effect of the combined administration of different doses of Glycyrrhizae Radix et Rhizoma and Atractylodis Macrocephalae Rhizoma on the cell proliferation. The effect of the drugs on the cell division rate and cell cycle of IEC-6 cells was detected by FCM. Quantitative Real-time PCR (qRT-PCR) was used to analyze the effect of the drugs on mRNA of p2l and p53 related to IEC-6 proliferation. Western blot was used to analyze the effect of the drugs on p2l and p53 protein expressions of IEC-6 cells. Atractylodis Macrocephalae Rhizoma could increase p53, p21 mRNA and proteins expression in DFMO-treated IEC-6 cells. The combined administration of different ratios of Atractylodis Macrocephalae Rhizoma and Glycyrrhizae Radix et Rhizoma could significantly down-regulate Atractylodis Macrocephalae Rhizoma's effect on p53, p21 mRNA and proteins expression in DFMO-treated IEC-6 cells and promote the proliferation of IEC-6 cells. The combined administration of Atractylodis Macrocephalae Rhizoma and Glycyrrhizae Radix et Rhizoma could down-regulate Atractylodis Macrocephalae Rhizoma's effect on DFMO-treated intestinal epithelial cells (IEC-6).
Animals ; Atractylodes ; chemistry ; Cell Line ; Cyclin-Dependent Kinase Inhibitor p21 ; genetics ; metabolism ; Drugs, Chinese Herbal ; pharmacology ; Epithelial Cells ; drug effects ; metabolism ; Gene Expression ; drug effects ; Glycyrrhiza ; chemistry ; Intestines ; drug effects ; metabolism ; Rats ; Rhizome ; chemistry ; Tumor Suppressor Protein p53 ; genetics ; metabolism

We previously reported that the p53 tumor suppressor protein plays an essential role in the induction of tetraploid G1 arrest in response to perturbation of the actin cytoskeleton, termed actin damage. In this study, we investigated the role of p53, ataxia telangiectasia mutated protein (ATM), and catalytic subunit of DNA-dependent protein kinase (DNA-PKcs) in tetraploid G1 arrest induced by actin damage. Treatment with actin-damaging agents including pectenotoxin-2 (PTX-2) increases phosphorylation of Ser-15 and Ser-37 residues of p53, but not Ser-20 residue. Knockdown of ATM and DNA-PKcs do not affect p53 phosphorylation induced by actin damage. However, while ATM knockdown does not affect tetraploid G1 arrest, knockdown of DNA-PKcs not only perturbs tetraploid G1 arrest, but also results in formation of polyploidy and induction of apoptosis. These results indicate that DNA-PKcs is essential for the maintenance of actin damage induced-tetraploid G1 arrest in a p53-independent manner. Furthermore, actin damage-induced p53 expression is not observed in cells synchronized at G1/S of the cell cycle, implying that p53 induction is due to actin damage-induced tetraploidy rather than perturbation of actin cytoskeleton. Therefore, these results suggest that p53 and DNA-PKcs independently function for tetraploid G1 arrest and preventing polyploidy formation.
Actins/*metabolism ; Apoptosis ; Catalytic Domain ; Cell Cycle Proteins/genetics/*metabolism ; Cell Line ; Cell Line, Tumor ; DNA-Activated Protein Kinase/chemistry/genetics/*metabolism ; DNA-Binding Proteins/genetics/*metabolism ; Furans/pharmacology ; *G1 Phase ; Gene Knockdown Techniques ; Humans ; Phosphorylation/drug effects ; Protein-Serine-Threonine Kinases/genetics/*metabolism ; Pyrans/pharmacology ; Tumor Suppressor Protein p53/*metabolism ; Tumor Suppressor Proteins/genetics/*metabolism

OBJECTIVETo investigate the roles of p53 and K-ras gene in carcinogenesis and development of the lung carcinoma induced by 3-methylcholanthrene (MCA) and diethylinitrosamine (DEN) in Wistar rats, and to elucidate the relationships between the protein expression and gene mutation of p53 and K-ras.

METHODSMicrodissection was used to obtain pure cell populations of each phase in the carcinogenesis and development of lung carcinoma induced by MCA and DEN. DNA of the microdissected cell populations was extracted and used to analyze the mutations of p53 exons 5 approximately 8 and K-ras exons 1 approximately 2 by PCR-SSCP. The expressions of p53 and K-ras protein in each phase were detected by immunohistochemistry.

RESULTSNo mutation and protein expression of p53 and K-ras was found in the 30 cases with normal bronchial epithelium. Mutation of p53 was detected in 3.1% of 18 hyperplasia and 14 squamous metaplasia cases, 28.6% of 21 dysplasia, 30.0% of 12 carcinomas in situ, 51.2% of 43 infiltration carcinomas, 52.9% of 17 metastases. The positive immunostaining rate of p53 protein was 0, 42.9%, 50.0%, 60.5% and 64.7% respectively. K-ras mutation rate was 0, 4.8%, 8.3%, 9.3%, 11.8% respectively, while the overexpression rate of K-ras protein was 15.6%, 19.0%, 25.0%, 41.9%, 52.9% respectively. p53 protein expression was closely related with p53 mutation (P < 0.005, Pearson's R = 0.599 6). There was no relationship between the protein expression and gene mutation of K-ras (P > 0.500).

CONCLUSIONSp53 gene mutation and K-ras overexpression were early events in the carcinogenesis and development of rat lung carcinoma induced by MCA and DEN, while K-ras mutation does not play any important role.

Animals ; Genes, p53 ; Genes, ras ; Humans ; Immunohistochemistry ; Lung Neoplasms ; chemically induced ; chemistry ; genetics ; Mice ; Mutation ; Polymerase Chain Reaction ; Polymorphism, Single-Stranded Conformational ; Rats ; Tumor Suppressor Protein p53 ; analysis ; ras Proteins ; analysis