Stepwise Use of Multimodality Imaging in a Rare Cardiac Intimal Sarcoma

•CISs are rare and aggressive primary cardiac tumors. •CIS presents with diverse pathology and is challenging to manage due to mass effect. •Multimodality cardiac imaging is valuable in diagnosis, surveillance, and management. •Because of limited therapeutic options, earlier diagnosis of CIS is essential.

Role of p53 suppression in the pathogenesis of hepatocellular carcinoma

In the world, hepatocellular carcinoma (HCC) is among the top 10 most prevalent malignancies. HCC formation has indeed been linked to numerous etiological factors, including alcohol usage, hepatitis viruses and liver cirrhosis. Among the most prevalent defects in a wide range of tumours, notably HCC, is the silencing of the p53 tumour suppressor gene. The control of the cell cycle and the preservation of gene function are both critically important functions of p53. In order to pinpoint the core mechanisms of HCC and find more efficient treatments, molecular research employing HCC tissues has been the main focus. Stimulated p53 triggers necessary reactions that achieve cell cycle arrest, genetic stability, DNA repair and the elimination of DNA-damaged cells’ responses to biological stressors (like oncogenes or DNA damage). To the contrary hand, the oncogene protein of the murine double minute 2 (MDM2) is a significant biological inhibitor of p53. MDM2 causes p53 protein degradation, which in turn adversely controls p53 function. Despite carrying wt-p53, the majority of HCCs show abnormalities in the p53-expressed apoptotic pathway. High p53 in-vivo expression might have two clinical impacts on HCC: (1) Increased levels of exogenous p53 protein cause tumour cells to undergo apoptosis by preventing cell growth through a number of biological pathways; and (2) Exogenous p53 makes HCC susceptible to various anticancer drugs. This review describes the functions and primary mechanisms of p53 in pathological mechanism, chemoresistance and therapeutic mechanisms of HCC.

CHIP inhibits odontoblast differentiation through promoting DLX3 polyubiquitylation and degradation

Dentin is the major hard tissue of teeth formed by differentiated odontoblasts. How odontoblast differentiation is regulated remains enigmatic. Here, we report that the E3 ubiquitin ligase CHIP is highly expressed in undifferentiated dental mesenchymal cells and downregulated after differentiation of odontoblasts. Ectopic expression of CHIP inhibits odontoblastic differentiation of mouse dental papilla cells, whereas knockdown of endogenous CHIP has opposite effects. Chip (Stub1) knockout mice display increased formation of dentin and enhanced expression of odontoblast differentiation markers. Mechanistically, CHIP interacts with and induces K63 polyubiquitylation of the transcription factor DLX3, leading to its proteasomal degradation. Knockdown of DLX3 reverses the enhanced odontoblastic differentiation caused by knockdown of CHIP. These results suggest that CHIP inhibits odontoblast differentiation by targeting its tooth-specific substrate DLX3. Furthermore, our results indicate that CHIP competes with another E3 ubiquitin ligase, MDM2, that promotes odontoblast differentiation by monoubiquitylating DLX3. Our findings suggest that the two E3 ubiquitin ligases CHIP and MDM2 reciprocally regulate DLX3 activity by catalyzing distinct types of ubiquitylation, and reveal an important mechanism by which differentiation of odontoblasts is delicately regulated by divergent post-translational modifications.

Cervical Liposarcoma Revisited: A Case Report and Scoping Literature Review

The commonest sites for liposarcoma are the retroperitoneum and lower extremities. Liposarcoma of the head and neck region is a rare and potentially life-threatening malignancy. Tumors originating in the right cervical space cause special diagnostic and therapeutic difficulties. In the present report, we describe a case of differentiated liposarcoma of the right cervical region. The tumor continued to grow slowly over 3 years before a definitive diagnosis was established. Extended extirpation of the tumor was performed and proved efficacious in that no recurrence has been observed for 4 years. Recommendations for earlier and accurate diagnosis and treatment of this rare neoplasm are discussed.

Ginsenoside Rg3 attenuates skin disorders via down-regulation of MDM2/HIF1α signaling pathway

Background

Thymic stromal lymphopoietin (TSLP) acts as a master switch for inflammatory responses. Ginsenoside Rg3 (Rg3) which is an active ingredient of Panax ginseng Meyer (Araliaceae) is known to possess various therapeutic effects. However, a modulatory effect of Rg3 on TSLP expression in the inflammatory responses remains poorly understood.

Methods

We investigated antiinflammatory effects of Rg3 on an in vitro model using HMC-1 cells stimulated by PMA plus calcium ionophore (PMACI), as well as an in vivo model using PMA-induced mouse ear edema. TSLP and vascular endothelial growth factor (VEGF) levels were detected using enzyme-linked immunosorbent assay or real-time PCR analysis. Murine double minute 2 (MDM2) and hypoxia-inducible factor 1α (HIF1α) expression levels were detected using Western blot analysis.

Results

Rg3 treatment restrained the production and mRNA expression levels of TSLP and VEGF in activated HMC-1 cells. Rg3 down-regulated the MDM2 expression level increased by PMACI stimulation. The HIF1α expression level was also reduced by Rg3 in activated HMC-1 cells. In addition, Rg3-administered mice showed the decreased redness and ear thickness in PMA-irritated ear edema. Rg3 inhibited the TSLP and VEGF levels in the serum and ear tissue homogenate. Moreover, the MDM2 and HIF1α expression levels in the ear tissue homogenate were suppressed by Rg3.

Conclusion

Taken together, the current study identifies new mechanistic evidence about MDM2/HIF1α pathway in the antiinflammatory effect of Rg3, providing a new effective therapeutic strategy for the treatment of skin inflammatory diseases.

Long non-coding RNA TUG1 sponges microRNA-381-3p to facilitate cell viability and attenuate apoptosis in cervical cancer by elevating MDM2 expression

OBJECTIVE

Based on the theory that long non-coding RNAs (lncRNAs) sponge microRNAs (miRNAs) to engage in cervical cancer development, this work was set out to investigate the possible role of lncRNA taurine upregulated gene 1 (TUG1) and miR-381-3p in the development of cervical cancer.

METHODS

TUG1, miR-381-3p and murine double minute 2 (MDM2) expression were measured in cervical cancer tissues and cells. The nexus between TUG1 and clinicopathological features of cervical cancer was discussed. The biological functions of TUG1, miR-381-3p and MDM2 on cervical cancer cell process were interpreted via gain- and loss-of-function experiments. Also, tumor xenograft in nude mice was conducted in vivo. The interactions between TUG1, miR-381-3p and MDM2 were identified.

RESULTS

TUG1 and MDM2 raised while miR-381-3p reduced in cervical cancer. TUG1 expression was related to tumor size, differentiation, international federation of gynecology and obstetrics stage and lymph node metastasis of cervical cancer. Restored miR-381-3p, depleted TUG1 or reduced MDM2 decreased viability, colony-forming, migration and invasion abilities, and facilitated apoptosis of cervical cancer cells. Xenografted tumors grew slowly upon injection with restored miR-381-3p and depleted TUG1. TUG1 bound to miR-381-3p and miR-381-3p targeted MDM2.

CONCLUSION

On all accounts, this present study provides evidence that silencing TUG1 depressed cervical cancer cell progression through miR-381-3p/MDM2 axis, highlighting a theoretical basis for cervical cancer treatment.

Immunohistochemical expression of p53 and murine double minute 2 protein in odontogenic keratocyst versus variants of ameloblastoma

Introduction

Oncogenes and tumor suppressor genes play a major role in cancer formation, growth, and progression. One of the important findings in this area is that murine double minute 2 (MDM2) oncogene is a negative regulator of wild-type p53. In tumors, expressing wild-type p53, inhibition of MDM2 expression will stabilize p53 and allow it to perform its proapoptotic function, while simultaneously preventing MDM2 from exerting its p53-independent oncogenic effects. The intracellular levels of p53 are tightly regulated by MDM2, as it is a key player in autoregulatory feedback loop under nonstressed conditions. The p53-MDM2 relationship is vital not only for essential functions of the cell, but it also appears to be an integrated part of the complex cellular network which supports the importance of this affair and is a hallmark for its coexistence.

Subjects and Methods

This study was designed to identify immunohistochemically the expression of p53 and MDM2 gene using monoclonal antibody in 60 cases of formalin-fixed paraffin-embedded tissue blocks, of which 20 cases were of solid multicystic ameloblastoma (SMA), 20 cases were of odontogenic keratocyst (OKC), and 20 cases were of unicystic ameloblastoma (UA).

Results

Immunoexpression of p53 and MDM2 was highest in OKC followed by SMA and was minimum in UA. Further results showed positive correlation between both the molecules.

Conclusion

The studied showed that the relationship has a significant role in cancer etiology and progression and therefore is an important topic for future research which should help in the development of new therapeutic agent against cancer.

Roles of DANCR/microRNA-518a-3p/MDMA ceRNA network in the growth and malignant behaviors of colon cancer cells

Background

The competing endogenous RNA (ceRNA) networks of long non-coding RNAs (lncRNAs) and microRNAs (miRs) have aroused wide concerns. The study aims to investigate the roles of lncRNA DANCR-associated ceRNA network in the growth and behaviors of colon cancer (CC) cells.

Methods

Differentially expressed lncRNAs between CC and paracancerous tissues were analyzed using microarrays and RT-qPCR. Follow-up studies were conducted to evaluate the correlation between DANCR expression and prognosis of CC patients. Loss-of-functions of DANCR were performed to identify its role in the malignant behaviors of CC cells. Sub-cellular localization of DANCR and the potential targets of DANCR were predicted and validated. Cells with inhibited DANCR were implanted into nude mice to evaluate the tumor formation and metastasis in vivo.

Results

DANCR was highly-expressed in CC tissues and cell lines, and higher levels of DANCR were linked with worse prognosis and less survival time of CC patients. Silencing of DANCR inhibited proliferation, viability, metastasis and resistance to death of CC cells. DANCR was found to be sub-localized in cytoplasmic matrix and to mediate murine double minute 2 (MDM2) expression through sponging miR-518a-3p in CC cells, during which the Smad2/3 signaling was activated. Likewise, silencing of DANCR in CC cells inhibited tumor formation and metastasis in vivo.

Conclusion

This study provided evidence that silencing of DANCR might inhibit the growth and metastasis of CC cells through the DANCR/miR-518a-3p/MDM2 ceRNA network and the defect of Smad2/3 while activation of the p53 signaling pathways. This study may offer novel insights in CC treatment.

[Effect of miR-513a-3p targeting MDM2 on proliferation, migration and invasion of gastric cancer cells]

Objective: To investigate the effects of miR-513a-3p on proliferation, migration and invasion of gastric cancer cells and its mechanism. Methods: The miR-NC (miR-negative control mimics), miR-513a-3p (miR-513a-3p mimics), anti-miR-NC, anti-miR-513a-3p, si-NC, si-MDM2 (murine double minute 2), miR-513a-3p+ pcDNA3.1 (co-transfected with miR-513a-3p and pcDNA3.1), miR-513a-3p+ pcDNA3.1-MDM2 (co-transfected with miR-513a-3p and pcDNA3.1-MDM2) were transfected into BGC-823 cells, respectively. The expression of miR-513a-3p was detected by real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR), and the protein expressions of cyclin D1, MMP-2, p21, E-cadherin, MDM2 were detected by western blot. The viability of BGC-823 cells of each group was detected by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT) assay. The migration and invasion of each group were detected by Transwell, the targeting relationship between miR-513a-3p and MDM2 was detected by double luciferase reporter gene assay. Results: The expression of miR-513a-3p in gastric epithelial cells GES-1 was 0.76±0.08, significantly higher than 0.21±0.02 in gastric cancer cells BGC-823 and 0.34±0.03 in MGC-803, respectively (P<0.05). The cell viabilities of the miR-NC group at 24 h, 48 h and 72 h were 0.57±0.05, 1.03±0.10, 1.43±0.14, respectively, while those of the miR-513a-3p group were 0.36±0.03, 0.48±0.05, and 0.63±0.06, respectively. The migration and invasion numbers of miR-NC group were 130±11.80 and 117±10.60, respectively, those of miR-513a-3p group were 58±5.64 and 50±5.13, respectively, and the differences were statistically significant (P<0.05). The cell viabilities of the si-NC group at 24 h, 48 h and 72 h were 0.53±0.05, 0.95±0.10, 1.36±0.14, respectively. Those of the si-MDM2 group were 0.39±0.04, 0.57±0.06, and 0.80±0.08, respectively. The cell migration and invasion of the si-NC group were 141±12.02 and 109±10.60, respectively, while those of the MDM2 group were 66±6.67 and 61±6.18, respectively, and the differences were statistically significant (P<0.05). The cell viabilities of the miR-513a-3p+ pcDNA3.1 group at 24 h, 48 h and 72 h were 0.34±0.03, 0.46±0.05, and 0.61±0.06, respectively. Those of miR-513a-3p+ pcDNA3.1-MDM2 group were 0.48±0.05, 0.82±0.08, 1.17±0.12, respectively. The migration and invasion of miR-513a-3p+ pcDNA3.1 group were 56±5.71 and 51±5.16, respectively, while those of miR-513a-3p+ pcDNA3.1-MDM2 group were 113±10.28 and 104±10.02, respectively, and the differences were statistically significant (P<0.05). Conclusion: miR-513a-3p may inhibit the proliferation, migration and invasion of gastric cancer cells through targeting regulation of MDM2, which will provide new targets for the prevention and treatment of gastric cancer.

MDM2 inhibition-mediated autophagy contributes to the pro-apoptotic effect of berberine in p53-null leukemic cells

AIMS

Berberine (BBR) is reported to induce apoptosis and inhibit migration of leukemic cells, but the underlying pharmacological mechanisms have not been fully revealed. This study aims to investigate the possible mechanisms from the perspective of autophagy.

MAIN METHODS

P-53-null leukemic cell lines Jurkat and U937 were used for the in vitro study. MDC staining was used for observation of autophagy in leukemic cells, and Western blot analysis was for determination of the expression levels of autophagy-associated proteins. Apoptosis of the leukemic cells was detected by flow cytometry. Cellular location of MDM2 was observed with immunofluorescence staining. Ubiquitination of MDM2 was assessed by immunoprecipitation. Male 6-8-week-old NOD/SCID mice were used for evaluating the effect of BBR on chemotherapy sensitivity in vivo.

KEY FINDINGS

BBR induced autophagy in p53-null leukemic cells, which was inhibited by autophagy inhibitors 3-methyladenine. 3-methyladenine also inhibited BBR-induced apoptosis in leukemic cells. In addition, BBR not only decreased MDM2 mRNA expression, but also enhanced MDM2 self-ubiquitination in leukemic cells. Forced overexpression of MDM2 reversed the effect of BBR on autophagy and apoptosis. Furthermore, BBR promoted doxorubicin-induced autophagy and cell death in the leukemic cells and overexpression of MDM2 suppressed these effects. In vivo, BBR combined with doxorubicin achieved better therapeutic effect than doxorubicin alone.

SIGNIFICANCE

MDM2 inhibits autophagy and apoptosis in leukemic cells in a p53-independent manner. BBR induces autophagy in p53-null leukemic cells through downregulating MDM2 expression at both transcriptional and post-transcriptional levels, which may contribute to the anti-cancer effect of BBR in leukemia.

Long lasting inhibition of Mdm2-p53 interaction potentiates mesenchymal stem cell differentiation into osteoblasts

The osteoblast generation from Mesenchymal stem cells (MSCs) is tightly coordinated by transcriptional networks and signalling pathways that control gene expression and protein stability of osteogenic "master transcription factors". Among these pathways, a great attention has been focused on p53 and its physiological negative regulator, the E3 ligase Murine double minute 2 (Mdm2). Nevertheless, the signalling that regulates Mdm2-p53 axis in osteoblasts remain to be elucidated, also considering that Mdm2 possesses numerous p53-independent activities and interacts with additional proteins. Herein, the effects of Mdm2 modulation on MSC differentiation were examined by the use of short- and long-lasting inhibitors of the Mdm2-p53 complex. The long-lasting Mdm2-p53 dissociation was demonstrated to enhance the MSC differentiation into osteoblasts. The increase of Mdm2 levels promoted its association to G protein-coupled receptors kinase (GRK) 2, one of the most relevant kinases involved in the desensitization of G protein-coupled receptors (GPCRs). In turn, the long-lasting Mdm2-p53 dissociation decreased GRK2 levels and favoured the functionality of A_2B Adenosine Receptors (A_2BARs), a GPCR dictating MSC fate. EB148 facilitated cAMP accumulation, and mediated a sustained activation of extracellular signal-regulated kinases (ERKs) and cAMP response element-binding protein (CREB). Such pro-osteogenic effects were not detectable by using the reversible Mdm2-p53 complex inhibitor, suggesting the time course of Mdm2-p53 dissociation may impact on intracellular proteins involved in cell differentiation fate. These results suggest that the long-lasting Mdm2 binding plays a key role in the mobilization of intracellular proteins that regulate the final biological outcome of MSCs.

YB-1 modulates the drug resistance of glioma cells by activation of MDM2/p53 pathway

Background

Y-box-binding protein-1 (YB-1) is aberrantly expressed in a variety of cancers. However, the biological functional role of YB-1 in glioma is not yet clear.

Methods

The expression of MDM2 and YB-1 was analyzed by real time PCR. Overexpression and knockdown of YB-1 in glioma cells were created by transfection of pcDNA-YB-1 and siRNA against YB-1, respectively. Cell viability was performed by CCK8 assay.

Results

Our findings showed that glioma tissues had higher expressions of YB-1 than that in cancer-free tissues in 54 glioma patients, which were also positively correlated with Murine MDM2 expression. Overexpression of YB-1 or MDM2 renders a drug resistance feature in glioma cell exposed to temozolomide (TMZ), by directly targeting p53. Genetic or chemical inhibition of MDM2 significantly blocked YB-1-modulated response of glioma cells to TMZ. Moreover, inhibition of YB-1 or MDM2 reduced glioma cells metastasis and mortality in mice.

Conclusion

YB-1 facilitates the resistance of glioma cells to TMZ by direct activation of MDM2/p53 signaling and represents a promising molecular target for glioma treatment.

Significant Association of the MDM2 T309G Polymorphism with Breast Cancer Risk in a Turkish Population

Background:

Breast cancer is a leading cause of death in women worldwide. Genetic polymorphisms have been reported to be important etiological factors. Murine double minute 2 (MDM2) T309G interacts with p53 and mutations in p53 are present in approximately 50% of all cancers. However, it has been reported that effect of the polymorphism on breast cancer risk may vary in different populations. Here, we therefore investigated whether there is an association between MDM2 T309G (rs2279744) polymorphism and breast cancer in a Turkish population.

Materials and Methods:

We analysed 110 patients with breast cancer and 138 matched? controls. For genotyping, polymerase chain reaction and restriction length fragment polymorphism methods were used.

Results:

A significant difference was observed between case and control groups with regard to the distribution of the MDM2 T309G polymorphism (p<0.05). There was a significantly higher frequency of the TT genotype in the control group (p=0.028; OR, 2.42; 95% CI, 1.09-5.37). However, we did not find any relationships among tumor grade and metastasis status and this polymorphism.

Conclusion:

This study indicates that the MDM2 T309G polymorphism GG genotype and the TG+GG combination may be risk factors for breast cancer in our Turkish population.

The association between murine double minute 2 (MDM2) rs2279744 and endometrial cancer risk in a Chinese Han population

Some studies investigated the association between the murine double minute 2 (MDM2) rs2279744 polymorphism and endometrial cancer susceptibility, but provided controversial or inconclusive results. Thus, we decided to perform this case-control study to determine the association between MDM2 rs2279744 polymorphism and endometrial cancer in a Chinese Han population. A total of 215 endometrial cancer patients and 212 cancer-free controls were included in this case-control study. We genotyped the MDM2 rs2279744 polymorphism by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). GG genotype showed a statistically significantly increased risk of developing endometrial cancer (OR=1.72, 95%CI 1.08-2.76, P=0.02). Statistically significant difference was observed when the patients and controls were compared according to G versus I (OR=1.40, 95%CI 1.07-1.84, P=0.01). A significantly higher frequency of G allele was observed in patients with stage III+IV, compared to stage I+II (OR=2.24, 95%CI 1.49-3.38, P=0.001). In conclusion, the study found that MDM2 rs2279744 polymorphism was significantly associated with endometrial cancer risk in a Chinese Han population.

Ameliorative effect of atractylenolide III in the mast cell proliferation induced by TSLP

Atractylenolide III (ATL-III) is an active compound of Atractylodes lancea, which has been widely used for the treatment of cancer. Cancer is closely connected with inflammation, and many anti-inflammatory agents are also used to treat cancer. We investigated the influence of ATL-III on thymic stromal lymphopoietin (TSLP)-induced inflammatory reactions. Pretreatment with ATL-III suppressed murine double minute 2 levels and promoted p53 levels in TSLP-treated human mast cell, HMC-1 cells. Mast cell proliferation increased by TSLP or IL-3 stimulation was significantly decreased by ATL-III pretreatment. Interleukin (IL)-13 and phosphorylated signal transducer and activator of transcription 3, 5, and 6 levels in TSLP-treated HMC-1 cells were also decreased by ATL-III pretreatment. In addition, ATL-III decreased the TSLP-induced production of proinflammatory cytokines (IL-6, IL-1β, tumor necrosis factor-α, and IL-8). ATL-III decreased the levels of Bcl2 and procaspase-3 and increased caspase-3 activation and cleaved PARP levels. Furthermore, ATL-III decreased TSLP-induced mast cell proliferation and the production of inflammatory cytokine by LAD2 cells. Taken together, these findings suggest that ATL-III plays a useful role as an anti-inflammatory agent and should be viewed as a potential anti-cancer agent.

Adenovirus siMDM2 and NDRG2 Gene Therapy Inhibits Cell Proliferation and Induces Apoptosis of Squamous Cell Carcinoma

Squamous cell carcinoma (SCC) is one of the most common skin cancers. In the present study, we explored the effects of depletion of murine double minute gene 2 (MDM2) together with overexpression of N-myc downstream-regulated gene 2 (NDRG2) on cutaneous SCC. In order to achieve high efficiency of gene knockdown and overexpression in SCC-13 cells, recombinant adenovirus carrying siMDM2 and NDRG2 expression construct was produced. We found Ad-siMDM2, Ad-NDRG2, and Ad-siMDM2-NDRG2 infections inhibit the growth of SCC-13 cells in vitro, and Ad-siMDM2-NDRG2 infection has the highest inhibitory effect. Subcutaneous injections of Ad-siMDM2, Ad-NDRG2, and Ad-siMDM2-NDRG2 into SCC-13 xenograft nude mice resulted in the reduction of tumor volume. Moreover, we found that apoptosis protein caspase 3 was up-regulated in the Ad-siMDM2-, Ad-NDRG2-, and Ad-siMDM2-NDRG2-treated groups. Our data indicate that the adenovirus-mediated MDM2 silencing and NDRG2 overexpression can synergistically inhibit local cancer cell proliferation, induce apoptosis, and further prevent metastases of SCC. Our study provides a promising method that can be further developed as a new therapeutic approach against SCC.

Murine double minute 2, a potential p53-independent regulator of liver cancer metastasis

Hepatocellular carcinoma (HCC) has emerged as one of the most commonly diagnosed forms of human cancer; yet, the mechanisms underlying HCC progression remain unclear. Unlike other cancers, systematic chemotherapy is not effective for HCC patients, while surgical resection and liver transplantation are the most viable treatment options. Thus, identifying factors or pathways that suppress HCC progression would be crucial for advancing treatment strategies for HCC. The murine double minute 2 (MDM2)-p53 pathway is impaired in most of the cancer types, including HCC, and MDM2 is overexpressed in approximately 30% of HCC. Overexpression of MDM2 is reported to be well correlated with metastasis, drug resistance, and poor prognosis of multiple cancer types, including HCC. Importantly, these correlations are observed even when p53 is mutated. Indeed, p53-independent functions of overexpressed MDM2 in cancer progression have been suitably demonstrated. In this review article, we summarize potential effectors of MDM2 that promote or suppress cancer metastasis and discuss the p53-independent roles of MDM2 in liver cancer metastasis from clinical as well as biological perspectives.

Clinical significance of expression of murine double minute 2 and ribosomal protein L23 in gastric cancer

AIM: To detect the expression of murine double minute 2 (MDM2) and ribosomal protein L23 (RPL23) in gastric cancer and explore their biological significance in the development of gastric cancer.

METHODS: The expression of MDM2 and RPL23 was detected by immunohistochemistry in 90 human gastric carcinoma specimens and 30 normal gastric tissue specimens. The correlation of MDM2 and RPL23 expression with the clinicopathologic features of gastric carcinoma was analyzed statistically.

RESULTS: The positive expression rate of MDM2 in gastric cancer tissues was significantly higher than that in the control group (62.2% vs 40%, P < 0.05), while the positive rate of RPL23 expression was significantly lower in gastric cancer tissues (30% vs 63.3%, P < 0.05). The expression of MDM2 and RPL23 in gastric cancer was negatively correlated (r = -0.23, P = 0.029). Multivariate analysis showed that overexpression of MDM2, low expression of RPL23, lymph node metastasis, depth of invasion and tumor size were significant prognostic factors.

CONCLUSION: MDM2 and RPL23 expression may be associated with the development of gastric cancer, and they may be used as prognostic markers and new therapeutic targets in gastric cancer.

Inhibition of MDM2 expression by rosmarinic acid in TSLP-stimulated mast cell

Rosmarinic acid (RA) has an anti-inflammatory property while thymic stromal lymphopoietin (TSLP) has an important role in mast cell-mediated inflammatory responses. Thus, the aim of this study was to determine the regulatory effect of RA in TSLP-stimulated human mast cell line, HMC-1 cells, and short ragweed pollen-induced allergic conjunctivitis mouse model. As a result, we found that RA significantly decreased the TSLP-induced mast cell proliferation and murine double minute (MDM) 2 expression. RA significantly decreased the levels of interleukin (IL)-13 and phosphorylated the signal transducer and activation of transcription 6 in the TSLP-stimulated HMC-1 cells. RA induced the increment of p53 levels, caspase-3 activation, and poly-ADP-ribose polymerase cleavage and the reduction of the procaspase-3 and Bcl2. RA significantly reduced the production of tumor necrosis factor-α, IL-1β, and IL-6 on the TSLP-stimulated HMC-1 cells. In addition, RA significantly reduced the levels of IgE, IL-4, and TSLP in the short ragweed pollen-induced allergic conjunctivitis mouse model. In conclusion, the results of the study suggest that RA has a significant anti-inflammatory effect on TSLP-induced inflammatory reactions. These effects of RA are likely to be mediated through inhibiting the MDM2 increased by TSLP.

Polymorphisms in promoter sequences of MDM2, p53, and p16 genes in normal Japanese individuals

Research has been conducted to identify sequence polymorphisms of gene promoter regions in patients and control subjects, including normal individuals, and to determine the influence of these polymorphisms on transcriptional regulation in cells that express wild-type or mutant p53. In this study we isolated genomic DNA from whole blood of healthy Japanese individuals and sequenced the promoter regions of the MDM2, p53, and p16(INK4a) genes. We identified polymorphisms comprising 3 nucleotide substitutions at exon 1 and intron 1 regions of the MDM2 gene and 1 nucleotide insertion at a poly(C) nucleotide position in the p53 gene. The Japanese individuals also exhibited p16(INK4a) polymorphisms at several positions, including position -191. Reporter gene analysis by using luciferase revealed that the polymorphisms of MDM2, p53, and p16(INK4a) differentially altered luciferase activities in several cell lines, including the Colo320DM, U251, and T98G cell lines expressing mutant p53. Our results indicate that the promoter sequences of these genes differ among normal Japanese individuals and that polymorphisms can alter gene transcription activity.

Research progress in roles of murine double minute 2 gene in the gastrointestinal tumor

Murine double minute 2 (MDM2), an oncogene discovered in recent years, can enhance cell survival activity, prolong cell survival duration, promote cell proliferation and stimulate tumor growth. In recent years, it was shown that MDM2 participated in the genesis and development of various tumors. In addition, MDM2 is associated with the invasion, metastasis and poor prognosis of malignant tumors, especially gastrointestinal tumors such as esophageal cancer, gastric cancer, colon cancer, liver cancer, etc. So it is significant to study the relationship between MDM2 and gastrointestinal tumors for tumor prevention and treatment. In combination with domestic and overseas literatures, this article provides a brief review of the research progress in the roles of MDM2 in the genesis, development and metastasis of gastrointestinal tumors.