Apoptosis ; Cell Proliferation ; Humans ; Neoplasms ; Tumor Suppressor Protein p53

The P53 gene has the important functions including induction of apoptosis, regulation of cell cycle, repair of DNA damage. The mutation of the P53 gene exists in more than 50% of human tumors and 13% of hematological malignancies. The P53 gene abnormality is closely related with the clinical course and prognosis of leukemia. The P73 or P63 gene, the member of the P53 family not only possesses similar to P53 activity of inducing apoptosis, activating transcription, but also plays different biological effects according to protein structural diversity, and even antagonises the function of the P53 gene. Researchers found that P73 or P63 gene also has the dual characteristics of the tumor suppressor and oncogene, and shows different expression and function in different types, different stages of leukemia. In this article, P53 family (P53, P73, P63) gene structure, biological function and the relationship of the three genes with the course, prognostic outcome, treatment and other clinical features of the leukemia are reviewed.
Gene Expression Regulation, Neoplastic ; Genes, p53 ; Humans ; Leukemia ; diagnosis ; genetics ; pathology ; Tumor Suppressor Protein p53 ; genetics

Adult ; Cytogenetics ; Genes, p53 ; Humans ; Leukemia, Myeloid, Acute/genetics* ; Mutation ; Prognosis ; Tumor Suppressor Protein p53/genetics*

To enhance the penetration of P53 into tumor cells by fusion it with the cell penetrating peptide 9R. The fusion gene of 9R-p53 was cloned into the expression vector. The fusion protein, CPPs-P53, was expressed and purified. We detected the rate of cell growth inhibition and apoptosis by MTT and Annexin-V-FITC/PI double stained method respectively for measuring its effect on tumor cells. CPPs-P53 and P53 were successfully expressed and purified, the purity of both proteins reached up to 90%. MTT assay showed that the cell growth inhibition by CPPs-P53 was more efficient than P53, and the rate of cell growth inhibition is dose-dependent. The apoptosis experiment showed that P53 could induce apoptosis of tumor cells. Compared with the P53, CPPs-P53 had a more significant effect in inducing cell apoptosis (**P < 0.01). The CPPs-P53 shows more significant effects than P53 in inhibiting cell growth and inducing apoptosis on tumor cells.
Apoptosis ; Cell Line, Tumor ; Cell-Penetrating Peptides ; pharmacology ; Humans ; Tumor Suppressor Protein p53 ; pharmacology

OBJECTIVE: To investigate the effect of RITA on TP53 mutant human mantle cell lymphoma (MCL) cell line Mino and its possible mechanism. METHODS: Mino cells were cultured in RPMI-1640 and treated with RITA at a concentration of 0-16 μmol/L for 24,48,72 hours. Cell viability was assessed by CCK-8 assay. The cells were treated by RITA (0-8 μmol/L) for 48 h, the cell apoptosis induced by RITA was detected by annexin V/PI flow cytometry. Western blot was performed to evaluate the expression of protein BCL-2, Caspase-3, Cleaved Caspase-3, PARP, MDM2, and P53 in Mino cells. RESULTS: After treatment with 0.5, 1, 2, 4, 8, and 16 μmol/L RITA for 48 h, the proliferation inhibition rate of Mino cells was (1.2±5.6)%, (14.9±4.9)%, (41.7±5.0)%, (61.8±2.4)%, (70.2±2.8)%, and (70.8±2.4)%, respectively. RITA could inhibit the proliferation of Mino cells significantly, and statistical analysis showed that the inhibition rate was increased with the increasing of RITA concentration (r=0.767). After the cells were treated by 4 μmol/L RITA for 24, 48, and 72 h, the proliferation inhibition rate was (25.2±3.8)%, (61.8±2.4)%, and (87.0±0.7)%, respectively. Satistical analysis showed that the inhibition rate was also increased with the increasing of treatment time (r=0.978). The apoptosis rate of Mino cells treated by 0, 2, 4, and 8 μmol/L RITA for 48 h was (5.4±0.4)%, (15.3±0.6)%, (38.7±1.7)%, and (50.8±1.1)%, respectively, and it showed dose-dependent manner (r=0.961). Western blot showed that with the increasing of RITA concentration, the BCL-2 protein expression was decreased in a dose-dependent manner (r=0.932), moreover, PARP cleavage and Caspase-3 activation were found, while the protein expression of MDM2 and P53 showed no change. CONCLUSION RITA can inhibit the proliferation and induce the apoptosis of Mino cells significantly. The mechanism may be dependent on the Caspase pathway, but independent on the P53 pathway.
Apoptosis ; Cell Line, Tumor ; Cell Survival ; Furans ; Humans ; Lymphoma, Mantle-Cell ; Mutation ; Tumor Suppressor Protein p53

OBJECTIVE: To screen for small molecular compounds with selective inhibitory activity against cutaneous melanoma cells with BAP1 deletion. METHODS: Cutaneous melanoma cells expressing wild-type BAP1 were selected to construct a BAP1 knockout cell model using CRISPR-Cas9 system, and small molecules with selective inhibitory activity against BAP1 knockout cells were screened from a compound library using MTT assay. Rescue experiment was carried out to determine whether the sensitivity of BAP1 knockout cells to the candidate compounds was directly related to BAP1 deletion. The effects of the candidate compounds on cell cycle and apoptosis were detected with flow cytometry, and the protein expressions in the cells were analyzed with Western blotting. RESULTS: The p53 activator RITA from the compound library was shown to selectively inhibit the viability of BAP1 knockout cells. Overexpression of wild-type BAP1 reversed the sensitivity of BAP1 knockout cells to RITA, while overexpression of the mutant BAP1 (C91S) with inactivated ubiquitinase did not produce any rescue effect. Compared with the control cells expressing wild-type BAP1, BAP1 knockout cells were more sensitive to RITA-induced cell cycle arrest and apoptosis (P < 0.0001) and showed an increased expression of p53 protein, which was further increased by RITA treatment (P < 0.0001). CONCLUSION Loss of BAP1 results in the sensitivity of cutaneous melanoma cells to p53 activator RITA. In melanoma cells, the activity of ubiquitinase in BAP1 is directly related to their sensitivity to RITA. An increased expression of p53 protein induced by BAP1 knockout is probably a key reason for RITA sensitivity of melanoma cells, suggesting the potential of RITA as a targeted therapeutic agent for cutaneous melanoma carrying BAP1-inactivating mutations.
Humans ; Melanoma ; Skin Neoplasms ; Tumor Suppressor Protein p53 ; Apoptosis ; Cell Division ; Tumor Suppressor Proteins/genetics* ; Ubiquitin Thiolesterase/genetics*

Adenoviridae ; genetics ; Genes, p53 ; Genetic Therapy ; methods ; Genetic Vectors ; Humans ; Neoplasms ; therapy ; RNA Interference ; Tumor Suppressor Protein p53 ; genetics

OBJECTIVETo observe the effect of recombinant adenovirus-mediated wild-type p53 gene on the number and proteins of centrosome in K562 cells. To explore the possibility of application of wild-type p53 gene therapy in the treatment of chronic myeloid leukemia.

METHODSThe recombinant adenoviruses carrying wild-type p53 gene (Ad5 wtp53), mutant p53 gene (Ad5 mtp53) or the green fluorescent protein (GFP) gene was repeatedly amplified and co-infected into K562 cells with cation polybrene. The optimal infection titer and infection time of the recombinant adenoviruses were determined by MTT assay, p53 mRNA and protein expression were determined by RT-PCR and Western blot respectively. The centrosomal structural protein gamma-tubulin and the spindle protein alpha-tubulin were marked simultaneously by indirect immunofluorescence staining, and the expression of the centrosomal gamma-tubulin protein, the mitosis and the number of centrosome were observed under the laser confocal microscopy.

RESULTSInfection efficiency with recombinant adenoviruses was facilitated by polybrene in K562 cells, and 4 microg/ml polybrene was chosen. The optimal adenovirus infection titer was 20,000 MOI and the optimal infection time was 72 hours. p53 mRNA and P53 protein can be expressed in K562 cells by Ad5wtp53 and Ad5mtp53. Both the expression of the centrosomal gamma-tubulin protein and the number of centrosomes were decreased after Ad5wtp53 infection.

CONCLUSIONThere is sustained expression of P53 protein in K562 cells after its infection by Ad5wtp53. Wild-type P53 protein can lead to the down-regulation of the number of centrosomes and the expression of centrosomal gamma-tubulin protein in K562 cells.

Adenoviridae ; genetics ; Centrosome ; metabolism ; Genes, p53 ; genetics ; Genetic Vectors ; Humans ; K562 Cells ; Transfection ; Tubulin ; metabolism ; Tumor Suppressor Protein p53 ; metabolism

Genes, p53 ; Genetic Predisposition to Disease ; Germ-Line Mutation ; Humans ; Li-Fraumeni Syndrome/genetics* ; Tumor Suppressor Protein p53/genetics*

PURPOSE: In spite of curative surgery and early postoperative intraperitoneal chemotherapy, the prognosis of patients with gastric cancer involving the serosal surface is poor. The aim of this study was to analyze p53 protein overexpression in these patients and to clarify the usefulness of p53 mutation as a prognostic indicator. METHODS: p53 protein overexpression was assessed by immunohistochemistry in 123 gastric cancer specimens. The correlation between p53 protein overexpression and clinicopathologic parameters and prognosis of the patients were analyzed. RESULTS: Overexpression of p53 protein was identified in 67 (54.5%) tumors and was more frequent in differentiated tumors than in undifferentiated tumors (67.4% vs. 46.8%; P=0.026). However, there were no statistically significant differences in the frequency of p53 protein overexpression according to age, sex, depth of invasion, lymph node metastasis, distant metastasis, pathologic stage, and Lauren classification. There was no statistically significant difference in 5-year survival rate according to the p53 protein overexpression (P=0.565). CONCLUSION: Overexpression of p53 protein could not predict the effectiveness of early postoperative intraperitoneal chemotherapy. Therefore, it could not be used as a prognostic indicator in patients with advanced gastric cancer who underwent gastrectomy and early postoperative intraperitoneal chemotherapy.
Gastrectomy ; Humans ; Immunohistochemistry ; Lymph Nodes ; Neoplasm Metastasis ; Prognosis ; Stomach Neoplasms ; Survival Rate ; Tumor Suppressor Protein p53