Clinical value of fluorescence in situ hybridization with MDM2 and DDIT3 probe in diagnosis of liposarcoma / 北京大学学报(医学版)

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.

Diagnostic value of MDM2 RNA in situ hybridization in atypical lipomatous tumor/well-differentiated liposarcoma and dedifferentiated liposarcoma / 中华病理学杂志

Objective: To investigate the value of MDM2 RNA in situ hybridization (RNA-ISH) in diagnosing atypical lipomatous tumor/well-differentiated liposarcoma (ALT/WDL) and dedifferentiated liposarcoma (DDL). Methods: A total of 26 ALT/WDL/DDLs diagnosed from March 2017 to May 2019 in West China Hospital, Sichuan University, Chengdu, China and 18 control cases were included. MDM2 RNA-ISH was performed on all samples and compared with the fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) regarding their performance in detecting MDM2. Results: All samples were detected successfully using the three methods. Among 26 ALT/WDL/DDLs, all cases showed MDM2 amplification and positivity for MDM2 RNA-ISH (26/26, 100%). Twenty-four (24/26, 92.3%) of the 26 tested cases were positive for MDM2 IHC while two of them were negative. Eighteen control cases were all negative for MDM2 FISH and RNA-ISH, and 15 (15/18) cases were negative for MDM2 IHC. The sensitivity and specificity of RNA-ISH were both 100%, and those of MDM2 IHC were 92.3% and 83.3%, respectively. Diffuse staining was identified in all MDM2 RNA-ISH positive ALT/WDL/DDLs, but identified in only 8/24 (33.3%) of the MDM2 IHC positive cases. Among the 11 ALT/WDL/DDL samples evaluated on tissue microarray, the positive rate of MDM2 RNA-ISH was 100% with diffuse staining in all cases. The positive rate of MDM2 IHC was 9/11 while only 1 of the 9 cases showed diffuse staining. The result of MDM2 RNA-ISH was identical to that of MDM2 FISH and was overall consistent with that of MDM2 IHC (Kappa=0.763, P<0.001). Conclusions: In ALT/WDL/DDLs, results of MDM2 RNA-ISH are highly consistent with those of FISH. MDM2 RNA-ISH is more sensitive and more specific and has more diffuse positive signals than the IHC. The findings indicate that MDM2 RNA-ISH is highly valuable for the diagnosis and differential diagnosis of ALT/WDL/DDLs.

Paratesticular liposarcoma: the clinicopathological features of nineteen cases / 中华病理学杂志

Objective: To investigate the clinicopathological features and differential diagnoses of paratesticular liposarcoma. Methods: The cases were collected from 2012-2020, from the archives of the Department of Pathology, Peking University Third Hospital, with diagnosis confirmed by histology, immunostaining and FISH tests. Results: Totally 19 patients were enrolled (including 11 in-hospital patients and 8 consultant cases). The patients aged 37-84 years (mean 57 years). The preoperative clinical diagnoses were spermatic cord/inguinal masses (nine patients), scrotal masses (seven patients), and inguinal hernia (three patients). Six lesions recurred after local resection, including one case extending from pelvic liposarcoma. Histologically, there were 10 cases of well-differentiated liposarcoma (WDLPS) and nine cases of dedifferentiated liposarcoma (DDLPS). WDLPSs mostly showed the combined features of lipoma-like, inflammatory and sclerosing subtypes (six patients); the other four WDLPSs had pure lipoma-like subtype features. DDLPSs were low-grade (three patients) or high-grade (six patients), with the morphology resembling myxofibrosarcoma, inflammatory myofibroblastoma, spindle cell sarcoma, pleomorphic undifferentiated sarcoma and pleomorphic liposarcoma. Intense inflammatory cells infiltration was commonly observed in five WDLPSs and two DDLPSs. Ossification was observed in three tumors. Immunohistochemically, the tumors were positive for MDM2 (8/10) and CDK4 (10/10), which were expressed in lipo-differentiating cells, spindle cells in WDLPS, and in dediffferentiated components. S-100 was only expressed by lipocytes (10/10). CD34 expression was positive and diffuse in the stromal cells of WDLPSs and focal or diffuse in dedifferentiated areas (10/10). FISH tests with an MDM2 gene probe were positive (12/12). Conclusions: Paratesticular liposarcoma may be overlooked by both clinicians and pathologists. WDLPS and DDLPS predominate, showing various histologic divergences. The presence of amplification of the 12q14-q15 region (containing the MDM2 and CDK4 genes) is helpful for making the correct diagnosis.

Primary colonic liposarcomatosis: report of a case with review of literature

The colon is a rare site of occurrence of liposarcoma, as either the primary site or by secondary involvement from a retroperitoneal liposarcoma. Liposarcomatosis denotes simultaneous occurrence of multiple liposarcomas. There are only 17 cases of primary colonic liposarcoma reported in the English literature­one of which was primary colonic liposarcomatosis. We depict the second case of primary colonic liposarcomatosis in a 57-year-old female who presented with abdominal swelling and pain. On exploratory laparotomy, two large masses were seen arising from the wall of the right colon along with multiple smaller masses attached to the colon. Right hemicolectomy with en bloc excision of the masses was performed along with hysterectomy and pelvic floor repair. Macroscopically, multiple exophytic masses and one endophytic mass were identified. The exophytic masses were of variable size and were found to hang from the colon by a thin pedicle simulating variable-sized appendices epiploicae. Histopathologically, the lesions showed the morphology of well-differentiated liposarcoma. This appears to be a case of primary colonic liposarcomatosis. There is only one other similar case reported in the English literature, to the best of our knowledge.

Novel natural product therapeutics targeting both inflammation and cancer / 中国天然药物

Inflammation is recently recognized as one of the hallmarks of human cancer. Chronic inflammatory response plays a critical role in cancer development, progression, metastasis, and resistance to chemotherapy. Conversely, the oncogenic aberrations also generate an inflammatory microenvironment, enabling the development and progression of cancer. The molecular mechanisms of action that are responsible for inflammatory cancer and cancer-associated inflammation are not fully understood due to the complex crosstalk between oncogenic and pro-inflammatory genes. However, molecular mediators that regulate both inflammation and cancer, such as NF-κB and STAT have been considered as promising targets for preventing and treating these diseases. Recent works have further demonstrated an important role of oncogenes (e.g., NFAT1, MDM2) and tumor suppressor genes (e.g., p53) in cancer-related inflammation. Natural products that target these molecular mediators have shown anticancer and anti-inflammatory activities in preclinical and clinical studies. Sesquiterpenoids (STs), a class of novel plant-derived secondary metabolites have attracted great interest in recent years because of their diversity in chemical structures and pharmacological activities. At present, we and other investigators have found that dimeric sesquiterpenoids (DSTs) may exert enhanced activity and binding affinity to molecular targets due to the increased number of alkylating centers and improved conformational flexibility and lipophilicity. Here, we focus our discussion on the activities and mechanisms of action of STs and DSTs in treating inflammation and cancer as well as their structure-activity relationships.

Effect and Regulatory Mechanism of Clock Gene Per1 on Biological Behaviors of Human Oral Squamous Carcinoma Cell / 中国医学科学院学报

<p><b>OBJECTIVE</b>To investigate the effect and regulatory mechanism of clock gene Per1 on the proliferation,apoptosis,migration,and invasion of human oral squamous carcinoma SCC15 cells.</p><p><b>METHODS</b>RNA 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).</p><p><b>RESULTS</b>shRNA-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).</p><p><b>CONCLUSIONS</b>Clock 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.</p>

Expression and significance of MMP-9 and MDM2 in the oncogenesis of lung cancer in rats

OBJECTIVE@#To observe the expression of matrix metalloproteinase-9 (MMP-9) and mouse double minute 2 homolog (MDM2) in the oncogenesis of lung cancer in rats and to explore their clinical value.@*METHODS@#A total of 140 rats were selected, of which 20 were selected randomly as the control group; and the remaining 120 as the observation group. The observation group was injected with benzopyrene to establish diseases model such as tissue proliferation, abnormal proliferation and lung cancer. Detected the MMP-9 levels of lung tissue by enzyme-linked assay, detected the MDM2 levels of lung tissue by immunochemistry assay.@*RESULTS@#The MMP-9 and MDM2 expression of the lung cancer group and the abnormal proliferation group were significantly higher than that in the tissue proliferation group and the control group, the difference was significant (P0.05). The MDM2 and MMP-9 expression were increased in turn in the small cell carcinoma, squamous cell carcinoma and adenocarcinoma, the difference was statistically significant (P0.05), and there is no significant difference of the MMP-9 and MDM2 expressions between stage I and stage II(P>0.05).@*CONCLUSIONS@#The expression of MMP-9 and MDM2 in lung tissue was associated with lung disease and lung cancer, both of them may be involved in the development and metastasis of lung cancer. Combined detection can be used as therapy and prognostic indicators for lung cancer.

The relationship and clinicopathological significance of Numb,MDM2 and p53 expression in human pancreatic cancer / 中华外科杂志

<p><b>OBJECTIVE</b>To study the relationship and clinicopathological significance of Numb,MDM2 and p53 expression in human pancreatic cancer.</p><p><b>METHODS</b>The 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.</p><p><b>RESULTS</b>IHC 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.</p><p><b>CONCLUSIONS</b>Numb acts as a tumor suppressor gene in the development of PDAC. Numb, MDM2 and p53 might coordinately participate in the development of PDAC.</p>

The role of Gli1 in the invasion and migration of pancreatic cancer cells / 中华外科杂志

<p><b>OBJECTIVE</b>To study the role and possible mechanism of glioma-associated oncogene-1 (Gli1) in regulating the cell invasion and migration of pancreatic cancer cells.</p><p><b>METHODS</b>Quantitative 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.</p><p><b>RESULTS</b>qRT-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.</p><p><b>CONCLUSION</b>Gli1 might contribute to the cell invasion and migration in pancreatic cancer via the regulation of MDM2, p53 and MMP-9 expression.</p>

Effect of quercetin on glioma cell U87 apoptosis and feedback regulation of MDM2-p53 / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of quercetin on apoptosis and feedback regulation of MDM2-p53 in multiform glioblastoma U87 cells in vitro.</p><p><b>METHODS</b>U87 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.</p><p><b>RESULTS</b>Quercetin 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.</p><p><b>CONCLUSION</b>Quercetin promotes the apoptosis of multiform glioblastoma U87 cells mediated by caspase-3 and influences the feedback balance of MDM2-p53.</p>

Localization and expression pattern of MDM2 in axon initial segments of neuron in rodent brain / 生理学报

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.

Immunohistochemical detection of p53 and MDM2 expressions in liposarcoma with World health organization classification.

BACKGROUND: Liposarcomas are among the most common soft tissue sarcomas in adulthood. AIM: The purpose of the study is to perform a histopathologic typing according to World Health Organization (WHO) classification of cases diagnosed with liposarcoma and to examine the difference of p53 and MDM2 expressions. MATERIALS AND METHODS: The haematoxylin-eosin stained sections of 48 subjects enrolled in the study have been evaluated on the basis of the WHO classification for liposarcoma and sections stained using p53 and MDM2. STATISTICAL ANALYSIS USED: Chi-Square test was applied. RESULTS: 20 subjects were diagnosed with well-differentiated liposarcoma (WLS), 16 myxoid liposarcoma (ML), 7 pleomorphic liposarcoma (PL), and 5 de-differentiated liposarcoma (DLS). The number of cases stained positive with MDM2 and p53 were positive correlated in all subjects (P = 0.02). p53 and MDM2 positivity increased in high grade tumors (P = 0.01). CONCLUSION: p53 and MDM2 immuno-reactivity was found to be potentially useful in liposarcoma diagnosis but a definitive implication would be rather unhealthy due to the small number of cases in our study.

Expression and significance of p53 and mdm2 in patients with leukoplakia cancer

OBJECTIVE@#To study the relationship of the expressions of p53 and mdm2 in leukoplakia cancer.@*METHODS@#RT-PCR was used to detect the mRNA of p53, mdm2 in patients with leukoplakia cancer. The frequencies of p53, mdm2 in peripheral blood were detected by flow cytometric analysis.@*RESULTS@#The expression of p53mRNA in normal oral mucosa, simple oral leukoplakia, no-simple oral leukoplakia and leukoplakia cancer were 7.7%, 27.3%,33.3%, 56.8%, respectively. The frequencies of p53 in normal oral mucosa, simple oral leukoplakia, no-simple oral leukoplakia and leukoplakia cancer were (0.3±0.1)%, (1.6±0.9)%, (1.9±1.1)%, (3.4±1.8)%. The expression of mdm2 mRNA in normal oral mucosa, simple oral leukoplakia, no-simple oral leukoplakia and leukoplakia cancer were 0.0%, 6.8%, 11.1%, 37.8%, respectively. The frequencies of mdm2 in normal oral mucosa, simple oral leukoplakia, no-simple oral leukoplakia and leukoplakia cancer were (0.1±0.1)%, (0.8±0.6)%, (1.2±0.8)%, (1.2±0.8)%. There was a positively correlation between p53 mRNA and mdm2 mRNA.@*CONCLUSIONS@#The positive rate of p53 and mdm2 cells in the peripheral blood increases in patients with leukoplakia cancer tissue and has positive correlation with the severity of leukoplakia cancer.

Mouse models of Mdm2 and Mdm4 and their clinical implications / 癌症

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.

Inhibitory effect of Akt inhibitor deguelin on the growth of PC-3 prostate cancer cells / 中华男科学杂志

<p><b>OBJECTIVE</b>To study the inhibitory effect of Akt inhibitor deguelin on PC-3 human prostate cancer cell lines and its possible mechanism.</p><p><b>METHODS</b>PC-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.</p><p><b>RESULTS</b>At 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.</p><p><b>CONCLUSION</b>Akt 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.</p>

Association of murine double minute 2 and P53 polymorphisms with breast cancer susceptibility / 中华预防医学杂志

<p><b>OBJECTIVE</b>To investigate the combined effects between the two polymorphisms murine double minute 2 (MDM2) rs2279744 T→G and P53 rs1042522 G→C on the genetic susceptibility of breast cancer.</p><p><b>METHODS</b>A total of 600 female patients with diagnosed breast cancer were consecutively recruited from the Yuhang district, Hangzhou city during March 2001 to May 2009. In the same period as the cases were collected, 600 healthy women living in Yuhang district, Hangzhou city were selected from a nutritional survey conducted. Peripheral blood lymphocytes were obtained from the study subjects and the demographic information were collected through questionnaires. PCR-restriction fragment length polymorphism (PCR-RFLP) was used for genotyping MDM2 rs2279744 T→G and P53 rs1042522 G→C. Logistic regression analysis was used to analyze the combined effects of the two polymorphisms on breast cancer risk.</p><p><b>RESULTS</b>The frequency of MDM2 rs2279744 GG, TG and TT genotypes were 31.5% (189/600), 45.5% (273/600), 23.0% (138/600) in case group and 19.0% (114/600), 49.2% (295/600), 31.8% (191/600) in control group. The frequency of P53 rs1042522 GG, GC and CC genotypes were 23.1% (139/600), 50.2% (301/600), 26.7% (160/600) in case group and 30.5% (183/600), 51.3% (308/600), 18.2% (109/600) in control group. Logistic regression analysis showed that carriers with rs2279744 TG, GG genotypes had a significant increased risk for developing breast cancer compared with rs2279744 TT carriers (OR = 1.31, 95%CI: 0.97 - 1.73 for TG; OR = 2.24, 95%CI: 1.61 - 3.09 for GG). When comparing with rs1042522 GG carriers, carriers with rs1042522 GC, CC genotypes had a significant increased risk for developing breast cancer (OR = 1.34, 95%CI: 0.94 - 1.68 for GC; OR = 1.89, 95%CI: 1.35 - 2.68 for CC). The united analysis of this two polymorphisms showed that compared with individuals carrying rs2279744 TT and rs1042522 GG (the frequency were 4.8% (29/600) in case group and 11.5% (69/600) in control group), carries with rs2279744 TG/GG and rs1042522 GC/GG genotypes (the frequency were 95.2% (571/600) in case group and 88.5% (531/600) in control group) showed significant higher risk in the susceptibility to breast cancer (OR = 2.30, 95%CI: 1.39 - 3.82 for TG/GC + GG; OR = 2.14, 95%CI: 1.29 - 3.55 for TT + GC/CC; OR = 2.86, 95%CI: 1.80 - 4.53 for TG/GG + GC/CC). The combination of MDM2 rs2279744 T→G and P53 rs1042522 G→C contributed to a significantly higher risk of breast cancer than did any one of the variant (P = 0.046). The risk of susceptibility to breast cancer was much higher when this two polymorphisms both variant.</p><p><b>CONCLUSIONS</b>The MDM2 rs2279744 T→G and P53 rs1042522 G→C may be risk factor for breast cancer. Significant combined effects between the two polymorphisms may contribute to the genetic susceptibility to breast cancer.</p>

ShRNA-mediated silencing of MDM2 inhibits growth of HepG2 hepatocellular carcinoma cells xenografted in nude mice / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To 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.</p><p><b>METHODS</b>Small 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.</p><p><b>RESULTS</b>siMDM2-1 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).</p><p><b>CONCLUSION</b>shRNA-mediated silencing of the MDM2 gene effectively inhibits HCC tumorigenesis of subcutaneously xenografted HepG2 cells in nude mice, and the mechanism may involve p53.</p>

Targeted therapy: tailoring cancer treatment / 癌症

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.

Correlation between Gli1 expression and clinicopathological significance in human pancreatic cancer / 中华外科杂志

<p><b>OBJECTIVE</b>To study the clinicopathological significance and relationship of Gli1, MDM2 and p53 expression in human pancreatic cancer.</p><p><b>METHODS</b>The 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.</p><p><b>RESULTS</b>IHC 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.</p><p><b>CONCLUSIONS</b>Gli1, 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.</p>

Combined effects of p53 and MDM2 polymorphisms on susceptibility and surgical prognosis in hepatitis B virus-related hepatocellular carcinoma

The p53 signaling pathway works as a potent barrier to tumor progression. Two single nucleotide polymorphisms (SNPs) in the gene loci of p53 pathway, p53 codon 72 Arg72Pro and MDM2 SNP309 (T > G), have been shown to cause perturbation of p53 function, but the effect of the two SNPs on the risk of hepatocellular carcinoma (HCC) remains inconsistent. This study investigated the influence of combined p53 Arg72Pro and MDM2 SNP309 on the risk of developing HCC in patients with chronic hepatitis B virus infection, and evaluated the significance of the two combined SNPs on patient prognosis. In total, 350 HCC patients, 230 non-HCC patients, and 96 healthy controls were genotyped for the p53 Arg72Pro and MDM2 SNP309. The combined p53 Pro/Pro and MDM2 G/G genotype was significantly associated with HCC risk (P = 0.047). Multivariate analysis indicated that combined p53 Pro/Pro and MDM2 G/G genotype was an independent factor affecting recurrence and survival (P < 0.05). Patients with combined p53 Pro/Pro and MDM2 G/G genotypes had a poorer prognosis than other genotypes, P < 0.01 for both disease-free survival (DFS) and overall survival (OS). DFS and OS rates also differed significantly between Barcelona Clinic Liver Cancer (BCLC) stage A patients with combined p53 Pro/Pro and MDM2 G/G and other genotypes (P < 0.05). Thus, the combined p53 Pro/Pro and MDM2 G/G genotype is associated with increased risk of developing HCC and is an independent adverse prognostic indicator in early stage HCC.