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*

OBJECTIVETo investigate the effect and regulatory mechanism of clock gene Per1 on the proliferation,apoptosis,migration,and invasion of human oral squamous carcinoma SCC15 cells.

METHODSRNA interference was used to knock down Per1 gene in human oral squamous cell carcinoma SCC15 cell line. Changes of cell proliferation and apoptosis were analyzed by flow cytometry. Transwell assay was carried out to assess cell migration and invasion. Real-time polymerase chain reaction was used to detect the mRNA expressions of Ki-67, murine double minute 2 (MDM2), c-Myc, p53, Bax, Bcl-2, metalloproteinase (MMP)2, MMP9, and vascular endothelial growth factor (VEGF).

RESULTSshRNA-mediated knockdown of Per1 promoted the proliferation, migration and invasion capacity, and inhibited cell apoptosis capacity of SCC15 cells (all P<0.05). Additionally, Per1 knockdown also increased the mRNA expressions of Ki-67, MDM2, Bcl-2, MMP2, and MMP9 and decreased the mRNA expressions of c-Myc, p53, and Bax (all P<0.05); however, the VEGF mRNA expression did not differ significantly after Per1 knockdown (P>0.05).

CONCLUSIONSClock gene Perl can regulate important tumor-related genes downstream such as Ki-67, MDM2, c-Myc, p53, Bax, Bcl-2, MMP2, and MMP9, and the aberrant expression of Per1 can affect tumor cell proliferation,apoptosis,migration and invasion. An in-depth study of Per1 may further clarify the mechanism of tumorigenesis and tumor development and thus provides new effective molecular targets for cancer treatment.

Apoptosis ; Carcinoma, Squamous Cell ; metabolism ; Cell Line, Tumor ; Cell Movement ; Cell Proliferation ; Gene Knockdown Techniques ; Humans ; Ki-67 Antigen ; metabolism ; Matrix Metalloproteinase 2 ; metabolism ; Matrix Metalloproteinase 9 ; metabolism ; Period Circadian Proteins ; metabolism ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; Proto-Oncogene Proteins c-mdm2 ; metabolism ; Proto-Oncogene Proteins c-myc ; metabolism ; RNA Interference ; Real-Time Polymerase Chain Reaction ; Tumor Suppressor Protein p53 ; metabolism ; Vascular Endothelial Growth Factor A ; metabolism ; bcl-2-Associated X Protein ; metabolism

OBJECTIVETo study the role and possible mechanism of glioma-associated oncogene-1 (Gli1) in regulating the cell invasion and migration of pancreatic cancer cells.

METHODSQuantitative real-time (qRT) -PCR was used to detect the effect of siRNA interference on Gli1, murine double minute 2 (MDM2) and p53 genes. Cell invasion and migration assays were used to observe the effect of Gli1, MDM2 and p53 silence on cell invasion and migration in p53 wild-type Capan-2 pancreatic cancer cells, respectively. Meanwhile, immunoblotting (IB) was used to detect the protein level of matrix metalloproteinase (MMP) -9, phospho-excelluar signal-regulated kinase (pERK) and phosphorylation protein kinase B (pAKT) in Gli1-silencing Capan-2 cells. The data were analyzed by paired t-test.

RESULTSqRT-PCR showed that the expression of Gli1, MDM2 and p53 is down-regulated 70.5% and 74.5%, 61.8% and 65.3%, and 73.8% and 78.2% after siRNA interference, compared with the mock and siRNA control groups, respectively. Cell invasion (94 ± 8) and migration (143 ± 8) in p53 wild-type Capan-2 cells transfected with Gli1siRNA were significantly decreased, compared with the siRNA control group (150 ± 7, 190 ± 10) (t = 6.584, P = 0.022; t = 8.266, P = 0.014) , while MDM2 silence inhibited cell invasion (experiment group:85 ± 12, control group: 138 ± 6) and migration (experiment group: 127 ± 9, control group:180 ± 10) in the same cells, respectively (t = 5.097, P = 0.036;t = 4.860, P = 0.040). However, cell invasion (experiment group: 153 ± 11, control group: 106 ± 7) and migration (experiment group: 209 ± 13, control group: 164 ± 8) in p53-silencing Capan-2 cells were significantly enhanced (t = 4.669, P = 0.043; t = 4.990, P = 0.038). IB showed that Gli1 silence down-regulated MMP-9 but not pERK and pAKT protein expression.

CONCLUSIONGli1 might contribute to the cell invasion and migration in pancreatic cancer via the regulation of MDM2, p53 and MMP-9 expression.

Animals ; Cell Line, Tumor ; Cell Movement ; Cell Proliferation ; Matrix Metalloproteinase 9 ; metabolism ; Mice ; Neoplasm Invasiveness ; Oncogene Proteins ; genetics ; metabolism ; Pancreas ; metabolism ; Pancreatic Neoplasms ; metabolism ; pathology ; Proto-Oncogene Proteins c-akt ; metabolism ; Proto-Oncogene Proteins c-mdm2 ; metabolism ; RNA, Small Interfering ; genetics ; Trans-Activators ; genetics ; metabolism ; Transfection ; Tumor Suppressor Protein p53 ; metabolism ; Zinc Finger Protein GLI1

To investigate the murine double minute 2 (MDM2) localization and expression pattern in brain, immunohistochemistry, immunofluorescent staining and immunoblotting methods were used to analyze it in brains of Kunming mice during postnatal development, in brains of adult SD rats and in primarily cultured neurons. The distribution of MDM2 and markers of axon initial segment (AIS) was analyzed by double immunolabeling. In addition, Nutlin-3, a MDM2 antagonist, was injected into hippocampus to analyze the effect on the distribution of MDM2 and AIS protein Nav1.6 in AIS. The results showed that the dynamic expression patterns of MDM2 protein in cerebral cortex and hippocampus of Kunming mice after birth were different. However, it was similar that MDM2 was gradually enriched to AIS during postnatal development, especially after postnatal day 7. The MDM2 in AIS was also observed in different brain regions of adult SD rat brain and in primarily cultured neurons, where MDM2 was colocalized with AIS markers such as AnkG and Nav1.6. In addition, hippocampal injection of Nutlin-3 could induce the loss of the characteristic distribution of MDM2 in AIS. Moreover, Nutlin-3 not only caused a decrease of Nav1.6 distributing in AIS, but also disrupted the polarized distribution of MAP2 in neurons. These results indicate that MDM2 can be enriched at the AIS of adult rodent brain, which might play a role in regulation of the maintenance of AIS function and neuronal polarity.
Animals ; Axons ; metabolism ; Cerebral Cortex ; metabolism ; Hippocampus ; metabolism ; Imidazoles ; pharmacology ; Mice ; NAV1.6 Voltage-Gated Sodium Channel ; metabolism ; Neurons ; metabolism ; Piperazines ; pharmacology ; Proto-Oncogene Proteins c-mdm2 ; metabolism ; Rats ; Rats, Sprague-Dawley

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

OBJECTIVETo study the relationship and clinicopathological significance of Numb,MDM2 and p53 expression in human pancreatic cancer.

METHODSThe expression of Numb,MDM2 and p53 proteins in 65 cases of paired paraffin embedded pancreatic ductal adenocarcinoma (PDAC) specimens and adjacent non-cancerous pancreas was detected by immunohistochemistry (IHC). The relationship among their expression and clinicopathological characters was analyzed.Westem blot was used to examine their expression in 16 paired fresh PDAC specimens and adjacent non-cancerous pancreatic tissues. Meanwhile,Numb expression in Capan-2, PANC-1 and AsPC-1 pancreatic cancer cells with different differentiation were detected by immunofluorescence (IF) , Westem blot and quantitative real-time (qRT) -PCR, respectively. Paired sample t-test, χ(2) test, Kaplan-Meier and Cox regression were used to analyze the results of our experiments, respectively.

RESULTSIHC showed that there was no differential expression of Numb in PDAC and adjacent pancreas (t = 1.746, P = 0.086) , while the expression of MDM2 and p53 was significantly increased in PDAC, compared to that in paired normal pancreas (t = 3.294, P = 0.002; t = 3.152, P = 0.002, respectively) .Numb expression was negatively associated with tumor size (χ² = 5.206, P = 0.023), differentiation (χ² = 7.802, P = 0.005) and UICC stage (χ² = 4.770, P = 0.029), while expression of MDM2 and p53 was positively associated with tumor T and TNM stage, respectively (χ² = 5.182, P = 0.023; χ² = 6.448, P = 0.011) . Correlation analysis showed a negative association between Numb and MDM2 (r = -0.283, P = 0.023) , but there was no relationship of them with p53 (P > 0.05) .Univariate and multivariate analysis revealed that Numb was a protective prognostic indicator for patients with PDAC (χ² = 5.408, P = 0.020). Moreover, patients with Numb positive and MDM2 negative expression had a significantly better overall survival (χ² = 5.868, P = 0.015). Western blot showed that Numb expression was much higher in well differentiated PDAC than that in paired normal pancreas (t = 1.092, P = 0.020) , while the expression of MDM2 and p53 was significantly increased in 16 cases of PDAC (t = 3.263, P = 0.005; t = 3.607, P = 0.003, respectively). Numb expression was gradually increased in pancreatic cancer cells with the increasing degree of cell differentiation detected by IF, Westem blot and qRT-PCR.

CONCLUSIONSNumb acts as a tumor suppressor gene in the development of PDAC. Numb, MDM2 and p53 might coordinately participate in the development of PDAC.

Carcinoma, Pancreatic Ductal ; genetics ; Humans ; Immunohistochemistry ; Kaplan-Meier Estimate ; Membrane Proteins ; metabolism ; Neoplasm Staging ; Nerve Tissue Proteins ; metabolism ; Pancreas ; metabolism ; Pancreatic Neoplasms ; genetics ; Prognosis ; Proto-Oncogene Proteins c-mdm2 ; metabolism ; Tumor Suppressor Protein p53 ; metabolism

Mdm2 and Mdm4 are two key negative regulators of the tumor suppressor p53. Deletion of either Mdm2 or Mdm4 induces p53-dependent early embryonic lethality in knockout mouse models. The tissue-specific deletion of Mdm2 induces p53-dependent apoptosis, whereas the deletion of Mdm4 induces both p53-dependent apoptosis and cell cycle arrest. Compared to Mdm4 deletion, Mdm2 deletion causes more severe phenotypic defects. Disrupting the Mdm2 and Mdm4 interaction using knockin mice models causes embryonic lethality that can be completely rescued by the concomitant loss of p53, suggesting that Mdm2 and Mdm4 heterodimerization is critical to inhibit p53 activity during embryogenesis. Overexpression of Mdm2 and Mdm4 in mice induces spontaneous tumorigenesis, which clearly indicates that Mdm2 and Mdm4 are bona fide oncogenes. Studies from these mouse models strongly suggest that blocking Mdm2- and Mdm4-mediated p53 inhibition is an appealing therapeutic strategy for cancer patients with wild-type p53 alleles.
Animals ; Apoptosis ; Cell Cycle Checkpoints ; Mice ; Mice, Knockout ; Models, Animal ; Proto-Oncogene Proteins ; genetics ; metabolism ; Proto-Oncogene Proteins c-mdm2 ; genetics ; metabolism ; Tumor Suppressor Protein p53 ; antagonists & inhibitors ; genetics ; metabolism ; Ubiquitin-Protein Ligases ; genetics ; metabolism

OBJECTIVETo study the clinicopathological significance and relationship of Gli1, MDM2 and p53 expression in human pancreatic cancer.

METHODSThe expression of Gli1, MDM2 and p53 proteins in 57 paired paraffin embedded pancreatic ductal adenocarcinoma (PDAC) specimens and adjacent non-cancerous pancreatic tissues was detected by immunohistochemistry. The relationship between their expression and clinicopathological characters was analyzed. Quantitative real-time PCR (qRT-PCR) was used to examine the expression of Gli1 mRNA level in 14 paired fresh PDAC specimens and adjacent non-cancerous pancreatic tissues. siRNA interference were used to further detect the close relationship among them.

RESULTSIHC showed the expression of Gli1 (50.9%), MDM2 (57.9%) and p53 (56.1%) was increased in 57 cases of pancreatic cancer compared to that in paired normal pancreatic tissues (33.3%, 26.3% and 17.5% respectively, t = 2.413, 2.848 and 2.960, all P < 0.05). Gli1 expression was positively associated with tumor TNM stage (χ(2) = 8.211, P = 0.004), invasion depth (χ(2) = 4.247, P = 0.039) and MDM2 expression (r = 0.299, χ(2) = 5.105, P = 0.024), while expression of MDM2 and p53 was associated with tumor invasion depth (χ(2) = 5.182, P = 0.023) and TNM stage (χ(2) = 5.696, P = 0.017), respectively. Univariate and multivariate analysis revealed that Gli1 was an independent adverse prognostic indicator for patients with PDAC (RR = 2.290, 95%CI: 1.051-4.992, P = 0.037), and patients with Gli1 and MDM2 co-expression had a significantly poorer overall survival than patients with their negative expression (P = 0.034). Gli1 mRNA expression was much higher in 14 cases of PDAC than that in adjacent normal pancreatic tissues (t = 2.926, P = 0.012). In p53 mutant AsPC-1 cells, Gli1 knockdown down regulated MDM2, but had no effect on p53 expression, whereas Gli1 knockdown down regulated MDM2 and up regulated p53 protein levels in p53 wild-type Capan-2 cells.

CONCLUSIONSGli1, MDM2 and p53 are overexpressed in PDAC, and are benefit for predicting patients' prognosis. Gli1can regulate MDM2 and wild-type p53 expression. Their co-expression might coordinately contribute to the development and progression of PDAC.

Adult ; Aged ; Carcinoma, Pancreatic Ductal ; metabolism ; Female ; Gene Expression Regulation, Neoplastic ; Humans ; Male ; Middle Aged ; Oncogene Proteins ; metabolism ; Pancreatic Neoplasms ; metabolism ; Prognosis ; Proto-Oncogene Proteins c-mdm2 ; metabolism ; RNA, Messenger ; metabolism ; Trans-Activators ; metabolism ; Tumor Suppressor Protein p53 ; metabolism ; Zinc Finger Protein GLI1

OBJECTIVETo construct a short hairpin (sh)RNA targeting the gene encoding the MDM2 oncoprotein in order to investigate its role in human hepatocellular carcinoma (HCC) and its potential for use as a gene therapy strategy to inhibit HCC growth in vivo.

METHODSSmall interfering (si)RNAs were designed targeting the MDM2 gene (siMDM2-1 and siMDM2-2) and unrelated sequences (negative control) and cloned into the expression plasmid pGCSilencer-U6-neo-GFP. A HCC mouse model was established by subcutaneous inoculation of HepG2 cells (2 x 10(6) in 0.2 ml) into 20 nude mice. The inoculated mice were divided into four equal groups for tumor-localized injections of saline, negative control siRNA plasmid, siMDM2-1 plasmid, and siMDM2-2 plasmid. Tumor growth was observed daily (by caliper measurement) for one month, when mice were sacrificed by cervical dislocation. The tumor mass was resected for analysis of tumor inhibition rate (% = [(average tumor weight of control group - average tumor weight of treatment group) / average tumor weight of control group x 100]) and effects on MDM2 and p53 mRNA and protein expression (by reverse transcription- PCR and western blotting, both normalized to beta-actin). Significance of between-group differences was assessed by one-way ANOVA or LSD test; pairwise comparisons were made by the Chi-squared test.

RESULTSsiMDM2-1 and siMDM2-2 suppressed the xenografted tumor growth remarkably (60.6% and 54.6% inhibition rates, respectively), significantly reduced the expression ofMDM2 gene (62.8% and 61.6%) and protein (60.7% and 59.5%), and significantly increased p53 gene (47.1% and 45.6%) and protein (45.9% and 44.3%) (all, P < 0.05).

CONCLUSIONshRNA-mediated silencing of the MDM2 gene effectively inhibits HCC tumorigenesis of subcutaneously xenografted HepG2 cells in nude mice, and the mechanism may involve p53.

Animals ; Carcinoma, Hepatocellular ; genetics ; pathology ; Cell Proliferation ; Hep G2 Cells ; Humans ; Liver Neoplasms ; genetics ; pathology ; Male ; Mice ; Mice, Nude ; Plasmids ; Proto-Oncogene Proteins c-mdm2 ; genetics ; metabolism ; RNA Interference ; RNA, Messenger ; genetics ; RNA, Small Interfering ; Transfection ; Tumor Suppressor Protein p53 ; metabolism ; Xenograft Model Antitumor Assays

Targeted therapies include small-molecule inhibitors and monoclonal antibodies, have made treatment more tumor-specific and less toxic, and have opened new possibilities for tailoring cancer treatment. Nevertheless, there remain several challenges to targeted therapies, including molecular identification, drug resistance, and exploring reliable biomarkers. Here, we present several selected signaling pathways and molecular targets involved in human cancers including Aurora kinases, PI3K/mTOR signaling, FOXO-FOXM1 axis, and MDM2/MDM4-p53 interaction. Understanding the molecular mechanisms for tumorigenesis and development of drug resistance will provide new insights into drug discovery and design of therapeutic strategies for targeted therapies.
Aurora Kinases ; metabolism ; Drug Resistance, Neoplasm ; Forkhead Box Protein M1 ; Forkhead Box Protein O3 ; Forkhead Transcription Factors ; metabolism ; Humans ; Molecular Targeted Therapy ; Neoplasms ; metabolism ; therapy ; Nuclear Proteins ; metabolism ; Phosphatidylinositol 3-Kinases ; metabolism ; Proto-Oncogene Proteins ; metabolism ; Proto-Oncogene Proteins c-mdm2 ; metabolism ; Signal Transduction ; TOR Serine-Threonine Kinases ; metabolism ; Tumor Suppressor Protein p53 ; metabolism