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*

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*

p53 is considered as the "master regulator" in DNA damage-induced cell apoptosis. However, p53 is the most frequently mutated gene in human cancers (more than 50 %). Thus the research of p53-independent pathway in cell apoptosis may ultimately provide new therapeutic opportunities for many cancers. It has been shown that Caspase 2, p73, p63, and NF-kappa B-related signaling pathways are involved in DNA damage-induced, p53-independent cell apoptosis. This article reviews the recent research progress in these signaling pathways.
Apoptosis ; genetics ; DNA Damage ; Humans ; Signal Transduction ; Tumor Suppressor Protein p53 ; genetics ; metabolism

OBJECTIVE: To explore the correlation of genetic mutations and clinical features of myelodysplastic syndromes (MDS) with scores of Revised International Prognostic Scoring System (IPSS-R). METHODS: Eighty-seven patients with de novo MDS were enrolled. Mutations of MDS-related genes and clinical features were used to determine the incidence and subtype of mutations. Clinical features and IPSS-R scores of the patients with high frequency mutations involving TET2, TP53, ASXL1, RUNX1 and SF3B1 genes were compared. RESULTS: Fifty-four patients (62.1%) harbored at least one point mutation. The incidences of various mutations were significantly different, with the incidence of MDS-EB-2 being 100% and MDS-SLD being only 38.9%. Compared with the wild types, patients harboring mutations had higher lactate dehydrogenase, higher β2 microglobulin, higher percentage of bone marrow blast cells and lower hemoglobin levels (P=0.027, <0.01, <0.01, 0.046, respectively). The IPSS-R scores of MDS patients with mutations were significantly higher than the wild types (P<0.01). The IPSS-R scores of the TP53 mutation groups were 7.82±1.83, which was significantly higher than the control group (3.77±1.66, P<0.01). No difference was found between the IPSS-R between patients carrying TET2, ASXL1, RUNX1, and SF3B1 mutations or the wild types (P>0.05). CONCLUSION Genetic mutations are commonly found in MDS. MDS patients with mutations have unique clinical laboratory characteristics. Although the prognostic value of most genes is controversial, TP53 is an definite indicator of poor prognosis.
DNA Mutational Analysis ; Humans ; Incidence ; Mutation ; Myelodysplastic Syndromes ; genetics ; Prognosis ; Tumor Suppressor Protein p53 ; genetics

Adenoviridae/genetics* ; Consensus ; Head and Neck Neoplasms/therapy* ; Humans ; 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

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

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

OBJECTIVETo investigate the synergistic antitumor effects of combined use of p14ARF gene and 5-fluorouracil (5-Fu) in pancreatic cancer.

METHODSA human pancreatic cancer cell line PC-3 was transfected with lipofectin-mediated recombinant p14ARF gene, and was then administered with 5-Fu. Cell growth, morphological changes, cell cycle, apoptosis, and molecular changes were measured using the MTT assay, flow cytometry, RT-PCR, Western blotting, and immunocytochemical assays.

RESULTSAfter transfection of p14ARF, cell growth was obviously inhibited, resulting in an accumulation of cells in the G(1) phase. The proportion of cells in the G(1) phase was significantly increased from 58.51% to 75.92%, and in the S and G(2)/M phases decreased significantly from 20.05% to 12.60%, and from 21.44% to 11.48%, respectively, as compared with those of the control groups. PC-3/p14ARF cells that underwent 5-Fu treatment had significantly greater G(2)/M phase accumulation, from 11.48% to 53.47%. The apoptopic index was increased in PC-3/p14ARF cells from 3.64% to 19.62%. The MTT assay showed p14ARF-expressing cells were significantly more sensitive to 5-Fu (0.01 - 10 mg/L) than those devoid of p14ARF expression (P < 0.01). Western blotting showed p14ARF upregulates p53 expression.

CONCLUSIONCombined use of p14ARF gene and 5-Fu acts synergistically to inhibit pancreatic cancer cell proliferation, suggesting a new anticancer strategy.

Fluorouracil ; pharmacology ; Humans ; Pancreatic Neoplasms ; genetics ; therapy ; Transfection ; Tumor Cells, Cultured ; Tumor Suppressor Protein p14ARF ; genetics ; Tumor Suppressor Protein p53 ; genetics ; Up-Regulation ; physiology