BACKGROUNDP53 is one of the most studied tumor suppressors in the cancer research, and over 50% of human tumors carry P53 mutations. MDM-2 is amplified and/or overexpressed in a variety of human tumors of diverse tissue origin. The aim of this study was to examine the expression of P53 protein and MDM-2 protein in gliomas, and to investigate the relationship between the expression of the two proteins and the histopathological grades of glioma. The relationship between MDM-2 protein expression and P53 protein expression was also analyzed.

METHODSThe expression of P53 protein and MDM-2 protein was immunohistochemically detected using monoclonal antibodies in 242 paraffin embedded tissues, including 30 normal brain tissues from patients with craniocerebral injury and 212 tissues from patients with primary glioma (grade I - II group: 5 cases of grade I, 119 cases of grade II; and grade III--IV group: 53 cases of grade III, and 35 cases of grade IV).

RESULTSThe P53 positive rate was significantly higher in the glioma groups than in the control group (P < 0.0001). The P53 positive rate was significantly higher in glioma tissues of grade III - IV than in glioma tissues of grade I - II group (P = 0.001). The MDM-2 positive rate was significantly higher in glioma groups than in the control group (P < 0.0001). There was no significant difference in the MDM-2 positive rate between the two glioma groups (P = 0.936). The expression of P53 protein was not related to expression of MDM-2 protein (P = 0.069)

CONCLUSIONSOverexpression of P53 protein might be related to the occurrence and progression of glioma. Overexpression of MDM-2 protein may play an important role in glioma tumorigenesis, but may not be involved in glioma progression. The overexpression of MDM-2 protein was an early event in malignant transformation of glioma. MDM-2 may be a key player in glioma in its own right.

Glioma ; metabolism ; pathology ; Humans ; Immunohistochemistry ; In Vitro Techniques ; Proto-Oncogene Proteins c-mdm2 ; metabolism ; Tumor Suppressor Protein p53 ; metabolism

Apoptosis ; drug effects ; Hep G2 Cells ; Hepatoblastoma ; metabolism ; Humans ; Oligonucleotides, Antisense ; pharmacology ; Proto-Oncogene Proteins c-mdm2 ; genetics

Siva-1, as a p53-inducible gene, has been shown to induce extensive apoptosis in a number of different cell lines. Recent evidence suggests that Siva-1 functions as a part of the auto-regulatory feedback loop that restrains p53 through facilitating Mdm2-mediated p53 degradation. Also, Siva-1 plays an important role in suppressing tumor metastasis. Here we review the current understanding of Siva-1-mediated apoptotic signaling pathway. We also add comments on the p53-Siva-1 feedback loop, the novel function of Siva-1 in suppressing tumor metastasis, and their potential implications.
Apoptosis ; Apoptosis Regulatory Proteins ; metabolism ; Feedback, Physiological ; Humans ; Models, Biological ; Neoplasm Metastasis ; Neoplasms ; pathology ; Proto-Oncogene Proteins c-mdm2 ; metabolism ; Signal Transduction ; Tumor Suppressor Protein p53 ; metabolism

OBJECTIVETo investigate the effect of quercetin on apoptosis and feedback regulation of MDM2-p53 in multiform glioblastoma U87 cells in vitro.

METHODSU87 cells exposed to different concentrations of quercetin (50, 100, and 150 µmol/L) were examined with flow cytometry, RT-PCR and Western blotting for detecting the cell apoptosis, MDM2 mRNA expression, and p53 and caspase-3 expressions.

RESULTSQuercetin induced obvious apoptosis in U87 cells in a concentration-dependent manner, with apoptosis rates of (12.40∓0.70)% at Q0, (22.53∓0.72)% at Q50, (29.06∓0.81)% at Q100, and (31.5∓0.45)% at Q150. Quercetin significantly increased the expressions of MDM2 mRNA and active caspase-3 protein but decreased the expression of p53 in the cells.

CONCLUSIONQuercetin promotes the apoptosis of multiform glioblastoma U87 cells mediated by caspase-3 and influences the feedback balance of MDM2-p53.

Apoptosis ; Caspase 3 ; metabolism ; Cell Line, Tumor ; drug effects ; Glioma ; metabolism ; pathology ; Humans ; Proto-Oncogene Proteins c-mdm2 ; metabolism ; Quercetin ; pharmacology ; Tumor Suppressor Protein p53 ; metabolism

OBJECTIVE: To investigate the relationship between the protein expression of MDM2 and P16 in laryngeal squamous cell carcinoma (LSCC), and their relationship with clinic pathological feature. METHOD: The expression of MDM2 and P16 were detected by S-P immunohistochemical method with mouse monoclonal anti MDM2 antibody and anti P16 antibody in 35 LSCC specimens, 21 specimens of precancerous larynx, 20 normal laryngeal specimens. RESULT: Expression of MDM2 positive in normal laryngeal specimens, precancerous larynx and LSCC specimens were 10.0%, 38.1%, 54.3% respectively (P < 0.05), and in I - III pathological grade laryngeal carcinoma were 38.1%, 66.7%, 100.0% respectively (P < 0.05); Expression of P16 positive in normal laryngeal specimens, precancerous larynx and LSCC specimens were 85.1%, 52.4%, 34.3% respectively (P < 0.05), and in I - III pathological grade laryngeal carcinoma were 52.4%, 11.1%, 0% respectively (P < 0.05). CONCLUSION Expression of MDM2 positive were higher with lower differentiation, so it's maybe helpful to diagnose LSCC. Expression of P16 positive were lower with lower differentiation, and there's no expression in III pathological grade LSCC, so it has positive effect on malignancy determination. Abnormal expression of MDM2 and P16 have different effects on LSCC development. Expression of MDM2 and P16 have negative correlation in LSCC.
Adult ; Aged ; Carcinoma, Squamous Cell ; metabolism ; pathology ; Cyclin-Dependent Kinase Inhibitor p16 ; metabolism ; Humans ; Laryngeal Neoplasms ; metabolism ; pathology ; Middle Aged ; Prognosis ; Proto-Oncogene Proteins c-mdm2 ; metabolism

OBJECTIVETo investigate the relationship between the expression of murine double minute 2 (MDM2) oncogene and non-Hodgkin lymphoma (NHL) in childhood.

METHODSThirty-one cases of NHL were enrolled in this study as patient group and 8 cases of lymphadenitis as control group. (1) Immunohistochemistry ultrasensitive S-P assay was used to detect the expression of MDM2 protein in pathological tissues in all cases. Positive cells were dyed yellow or brown in nuclei. MDM2 positive cell was defined as >/= 10% of the tumor cells were positive, which was overexpression of MDM2 protein. (2) RT-PCR (reverse transcription-polymerase chain reaction) was performed to value the overexpression of MDM2 mRNA in the pathological tissues and mononuclear cells in peripheral blood. While the ratio of MDM2/beta-actin was >16% was defined as overexpression of MDM2 mRNA.

RESULTS(1) Rates of overexpression of MDM2 protein and MDM2 mRNA were 64.5% and 61.3%, respectively, which were significantly different as compared to that of control group (P < 0.05 and P < 0.01, respectively). (2) The relationship analysis among subgroups in the experiment group showed that the overexpression of MDM2 protein did not correlate with classifications of working formulation, cellular origin, sex, clinical stage and involved extranodal sites (P > 0.05), but significantly correlated with classifications of B status and the increased serum LDH level (P < 0.05). It was shown that the overexpression of MDM2 mRNA did not correlate with classifications of working formulation, cellular origin, sex and clinical stage (P > 0.05), significantly correlated with B status (P < 0.05), and was remarkably significantly correlated with the involved extranodal sites and the increased serum LDH level (P < 0.01). (3) It was demonstrated that the overexpression of MDM2 mRNA in the pathological tissues was similar to the overexpression of MDM2 protein in the pathological tissues and MDM2 mRNA in peripheral blood (P > 0.05, kappa = 0.655 and 0.571), and the overexpression of MDM2 protein in the pathological tissues was similar to that of MDM2 mRNA in peripheral blood (P > 0.05, kappa = 0.609).

CONCLUSIONS(1) The rate of MDM2 oncogene overexpression was quite high. (2) The overexpression of MDM2 protein in pathological tissues determined by using immunohistochemistry ultrasensitive S-P assay was similar to that of MDM2 mRNA in pathological tissues detected by using RT-PCR method. Both methods might be used to detect the overexpression of MDM2 oncogene in the cases of childhood NHL. (3) The overexpression of MDM2 oncogene related to the poor status and poor prognosis of patients with childhood NHL.

Biomarkers, Tumor ; analysis ; blood ; Child ; Humans ; Immunohistochemistry ; Lymphoma, Non-Hodgkin ; blood ; genetics ; metabolism ; Neoplasm Proteins ; blood ; genetics ; Oncogenes ; Proto-Oncogene Proteins c-mdm2 ; blood ; genetics ; metabolism ; RNA, Messenger

OBJECTIVETo study the inhibitory effect of Akt inhibitor deguelin on PC-3 human prostate cancer cell lines and its possible mechanism.

METHODSPC-3 human prostate cancer cells were cultured in deguelin at the concentrations of 10, 100, 500 and 1 000 nmol/L for 24, 48 and 72 hours, respectively. Then the inhibitory effect of deguelin on the proliferation of the PC-3 cells was determined by MTT assay and that on the cell cycle was detected by flow cytometry. The expression levels of MDM2 and GSK3beta mRNA were measured by RT-PCR and those of MDM2 and GSK3beta proteins by Western blot.

RESULTSAt 24, 48 and 72 hours, the inhibition rates of deguelin on the proliferation of the PC-3 prostate cancer cells were (91.10 +/- 3.75), (86.39 +/- 1.16) and (79.51 +/- 2.63)% at 10 nmol/L, (82.46 +/- 3.65), (76.84 +/- 0.97) and (69.69 +/- 2.30) % at 100 nmol/L, (81.46 +/- 0.41), (75.56 +/- 1.12) and (54.07 +/- 3.21)% at 500 nmol/L, and (66.77 +/- 2.82), (58.22 +/- 0.35) and (39.34 +/- 2.40)% at 1000 nmol/L, all with statistically significant differences from the control group (P < 0.01). Deguelin at 10, 100, 500 and 1 000 nmol/L increased the cell cycles blocked in the G0/G1 phase ([62.4 +/- 2.2], [63.6 +/- 1.1 ], [65.0 +/- 0.3] and [66.5 +/- 1.9]%, P < 0.01) and reduced the percentage of the S-phase cells ([14.7 +/- 2.4], [11.1 +/- 5.2], [5.8 +/- 1.1] and [7.0 +/- 0.6]%, P < 0.01). RT-PCR and Western blot showed markedly up-regulated expressions of GSK3 P3 a3beta down-regulated expressions of MDM2 mRNA and proteins in the PC-3 cells treated with deguelin.

CONCLUSIONAkt inhibitor deguelin can inhibit the proliferation of PC-3 human prostate cancer cells by affecting the down-stream signal molecules GSK3P3 and betaDM2 in the Akt pathway.

Cell Line, Tumor ; Cell Proliferation ; drug effects ; Glycogen Synthase Kinase 3 ; metabolism ; Glycogen Synthase Kinase 3 beta ; Humans ; Male ; Prostatic Neoplasms ; metabolism ; Proto-Oncogene Proteins c-akt ; antagonists & inhibitors ; Proto-Oncogene Proteins c-mdm2 ; metabolism ; Rotenone ; analogs & derivatives ; pharmacology

Animals ; Genes, p53 ; Genetic Therapy ; Humans ; Neoplasms ; genetics ; metabolism ; therapy ; Proto-Oncogene Proteins c-mdm2 ; metabolism ; Tumor Suppressor Protein p53 ; genetics ; metabolism

OBJECTIVE: To investigate the value of using MDM2 amplification probe and DDIT3 dual-color, break-apart rearrangement probe fluorescence in situ hybridization (FISH) technique in the diagnosis of liposarcoma. METHODS: In the study, 62 cases of liposarcoma diagnosed in Peking University First Hospital from January 2015 to December 2019 were analysed for clinicopathological information. Of these 62 cases of liposarcoma, all were analysed for MDM2 amplification and 48 cases were analysed for DDIT3 rearrangement using a FISH technique. Our study aimed to evaluate the status of MDM2 and DDIT3 by FISH in liposarcoma and correlate it with diagnosis of different subtypes of liposarcoma. The subtypes of liposarcoma were classified according to the FISH results, combined with the relevant clinicopathological features. RESULTS: The patients aged 31-89 years (mean: 59 years) with a 1.75:1 male to female ratio. Histologically, there were 20 cases of atypical lipomatous tumour/well-differentiated liposarcoma (ALT/WDLPS), 26 cases of dedifferentiated liposarcoma (DDLPS), 13 myxoid liposarcoma (MLPS) and 3 pleomorphic liposarcoma (PLPS). Tumors with DDLPS (23/26) and WDLPS (8/20) were localized retroperitoneally, while both tumours of MLPS and PLPS were localized extra-retroperitoneally, and the difference of sites among the four subtypes of liposarcoma was statistically significant (P < 0.05). Histologically, varied mucoid matrix could be observed in the four subtypes of liposarcoma, and the difference was statistically significant (P < 0.05). MDM2 gene amplification was demonstrated in all cases of ALT/WDLPS and DDLPS (100%, 20/20 and 26/26 respectively); DDIT3 gene rearrangement was noted only in MLPS (100%, 13/13); most cases of DDLPS (96.2%, 25/26) and ALT/WDLPS (83.3%, 5/6, 6 cases selected for detection) demonstrated the picture of amplification of the DDIT3 telomeric tag. According to the instructions of DDIT3 break-apart rearrangement probe, the 5' telomere probe and 3' centromere probe spanned but did not cover the DDIT3 gene itself, on the contrary, the 5' telomere probe covered the CDK4 gene, while the DDIT3 and CDK4 gene were located adjacent to each other on chromosome, therefore, when the amplification signal appeared on the telomeric tag of the DDIT3 rearrangement probe, it indeed indicated the CDK4 gene amplification rather than the DDIT3 gene rearrangement. Then the 10 cases with DDIT3 telomeric tag amplification were selected for CDK4 and DDIT3 gene amplification probe FISH tests, and all the cases showed CDK4 gene amplification (100%, 10/10) and two of the 10 cases demonstrated co-amplification of CDK4 and DDIT3 (20%, 2/10); DDIT3 polysomy detected by DDIT3 gene rearrangement probe was found in 1 case of DDLPS and 2 cases of PLPS (66.7%, 2/3) with morphology of high-grade malignant tumour and poor prognosis. CONCLUSION Our results indicate that a diagnosis of different subtype liposarcoma could be confirmed based on the application of MDM2 and DDIT3 FISH, combined with clinicopathological findings. It is also noteworthy that atypical signals should be correctly interpreted to guide correct treatment of liposarcomas.
Male ; Female ; Humans ; In Situ Hybridization, Fluorescence/methods* ; Cyclin-Dependent Kinase 4/metabolism* ; Liposarcoma/pathology* ; Lipoma/pathology* ; Gene Amplification ; Transcription Factor CHOP/genetics* ; Proto-Oncogene Proteins c-mdm2/metabolism*

Gankyrin is an oncoprotein containing seven ankyrin repeats that is overexpressed in hepatocellular carcinoma (HCC). Gankyrin binds to Mdm2, which results in accelerated ubiquitylation via degradation of p53, and it also plays an important role in cell proliferation. However, little is known about the relationships between p53 levels, cell proliferation, and gankyrin over-expression. In order to investigate the influence of gankyrin protein on p53 and Mdm2 in a zebrafish model, we injected human gankyrin (hgankyrin) containing expression vectors (pCS2-hgankyrin, pCS2-hgankyrin-EGFP) into zebrafish embryos. To measure p53 and Mdm2 expression in hgankyrin-injected embryos, RT-PCR, Northern blot and in-situ hybridization and BrdU immunostaining were used. In addition, to know the effect of hgankyrin on cell proliferation in vitro, cell viability assays such as MTT, trypan blue staining and RT-PCR following transfection of hgankyrin-containing vector into HEK 293 cell line were performed. In vivo results indicated that p53 mRNA levels decreased but those of Mdm2 were not decreased in the presence of hgankyrin. These results suggest that gankyrin downregulates p53 expression and not Mdm2 expression. In the study of cell proliferation, BrdU-positive cells were predominantly increased in the head and tail regions in hgankyrin-injected zebrafish. Additional in vitro studies using trypan blue staining and MTT assay showed that gankyrin-expressing HEK 293 cells proliferated at a faster rate, indicating that gankyrin promotes cell proliferation. Our results demonstrate that hgankyrin overexpression downregulates p53 expression and promotes cell proliferation in zebrafish. Gankyrin may play an important role in tumorigenesis via its effects on p53 and cell proliferation.
Animals ; Cell Line ; Cell Proliferation ; Cell Survival ; Gene Expression ; Humans ; In Situ Hybridization ; Models, Animal ; Proteasome Endopeptidase Complex/*genetics/*metabolism ; Proto-Oncogene Proteins/*genetics/*metabolism ; Proto-Oncogene Proteins c-mdm2/genetics/metabolism ; Tumor Suppressor Protein p53/genetics/*metabolism ; Zebrafish