Association between MDM2 promoter SNP309 T/G polymorphism and liver cancer risk - a meta-analysis

Polyporus umbellatus inhibited tumor cell proliferation and promoted tumor cell apoptosis by down-regulating AKT in breast cancer

Breast cancer (BC) is the foremost cause of cancer-related mortality in women worldwide. Polyporus umbellatus is a polysaccharide preparation of the Chinese traditional herb medicine, which has been explored as an inhibitory compounds in suppressing many cancers. And AKT has been known as an essential signaling pathway to regulate cell proliferation and apoptosis via Mdm2/p53 and Caspase-3 signaling pathways respectively. In our study, western blot, RT-PCR, immunochemical assay, immunofluorescence as well as flow cytometry were performed in vitro or in vivo to determine the effects of Polyporus umbellatus on the progression of human laryngeal cancer. First, the breast cancer cell growth, invasion and migration were inhibited, as well as the tumor volume in nude mice was down-regulated for Polyporus umbellatus use. Additionally, our data also showed that Polyporus umbellatus suppressed breast cancer cells proliferation, which was linked with the down-regulation of AKT activation by Polyporus umbellatus treatment. Mdm was inactivated while p53 was stimulated for Polyporus umbellatus administration, displaying inhibitory role in tumor growth. Furthermore, Polyporus umbellatus could up-regulate breast cancer cells in G0/G1 phase during cell cycle, and at the same time reducing cells in S phase. Also, flow cytometry and western blot assays suggested that apoptosis was induced by the administration of Polyporus umbellatus, which enhanced Caspase-3 expressions by AKT-regulated anti-apoptotic and pro-apoptotic signals. In conclusion, our data indicated that Polyporus umbellatus had a potential role in controlling human breast cancer through inhibiting tumor cell proliferation, inducing apoptosis regulated by AKT, which might provide a therapeutic strategy for breast cancer suppression in the future.

SCYL1BP1 has tumor-suppressive functions in human lung squamous carcinoma cells by regulating degradation of MDM2

SCY1-like 1-binding protein 1 (SCYL1BP1) is a newly identified transcriptional activator domain containing protein with many unknown biological functions. Recently emerging evidence has revealed that it is a novel regulator of the p53 pathway, which is very important for the development of human cancer. However, the effects of SCYL1BP1 on human lung squamous carcinoma cell biological behavior remain poorly understood. In this study, we present evidence that SCYL1BP1 can promote the degradation of MDM2 protein and further inhibit the G1/S transition of lung squamous carcinoma cell lines. Functional assays found that reintroduction of SCYL1BP1 into lung squamous carcinoma cell lines significantly inhibited cell proliferation, migration, invasion and tumor formation in nude mice, suggesting strong tumor suppressive function of SCYL1BP1 in lung squamous carcinoma. Taken together, our data suggest that the interaction of SCYL1BP1/MDM2 could accelerate MDM2 degradation, and may function as an important tumor suppressor in lung squamous carcinomas.

The MDM2 SNP309T>G polymorphism increases bladder cancer risk among Caucasians: a meta-analysis

Published studies have evaluated associations between the MDM2 SNP309T>G polymorphism and bladder cancer susceptibility. However, these generated inconsistent results. The aim of the present investigation was to quantify the strength of association between MDM2 SNP309T>G polymorphism and bladder cancer risk by conducting a meta-analysis. We searched PubMed and Embase for related studies that had been published in English before April 1, 2014 and associations were assessed by summarizing the odds ratios (ORs) with the corresponding 95% confidence intervals (CIs). Five case-control studies with a total of 972 cases and 1,012 controls were finally identified to be eligible for the meta-analysis. Overall, the results indicated that there was no significant association between the MDM2 SNP309T>G polymorphism and bladder cancer risk (for the allele model G vs. T: OR=1.08, 95% CI 0.85-1.36, p=0.54; for the co-dominant model GG vs. TT: OR=1.20, 95% CI 0.74-1.93, p=0.46; for the dominant model GG+GT vs. TT: OR=0.98, 95% CI 0.80-1.20, p=0.83; for the recessive model GG vs. GT+TT: OR=1.20, 95% CI 0.83-1.74, p=0.33). However, on subgroup analysis by ethnicity, significant associations were found in Caucasians in three models (for the allele model G vs. T: OR=1.41, 95% CI 1.10-1.81, p=0.006; for the co-dominant model GG vs. TT: OR=2.16, 95% CI 1.28-3.63, p=0.004; for the recessive model GG vs. GT+TT: OR=2.06, 95% CI 1.31-3.22, p=0.002). In summary, the present meta-analysis provides evidence that the genotype for the MDM2 SNP309T>G polymorphism may be associated with genetic susceptibility to bladder cancer among Caucasians.

Genetic association of single nucleotide polymorphisms in P53 pathway with gastric cancer risk in a Chinese Han population

The tumor suppressor gene P53 plays an important role in carcinogenesis, and the P53 pathway is central both in reducing cancer frequency and in mediating the response of cancer therapies. MDM2, MDM4 and Hausp genes are all critical regulators of the tumor suppressor P53. Many studies have evaluated the association of single nucleotide polymorphisms (SNPs) in P53 pathway with the risk of common cancers. However, the results are still inconclusive. In this work, we analyzed the association of SNPs in P53 (rs1042522), MDM2 (rs2279744), MDM4 (rs1380576) and Hausp (rs1529916) genes with gastric cancer in a hospital-based Chinese Han population (642 cases and 720 cancer-free controls). We found that the polymorphisms of P53 (rs1042522) and MDM2 (rs2279744) are associated with gastric cancer risk, whereas no significant association was observed between variant genotype of other two polymorphisms (MDM4 rs1380576 and Hausp rs1529916) and gastric cancer risk.

The T309G murine double minute 2 gene polymorphism is an independent prognostic factor for patients with renal cell carcinoma

The purpose of this study was to evaluate the association of the T309G MDM2 gene polymorphism with renal cell carcinoma (RCC) risk, pathology, and cancer-specific survival (CSS). T309G MDM2 was genotyped in 449 Caucasians, including 240 with RCC and 209 cancer-free controls. The T309G MDM2 genotype was TT in 174 (38.8%), GT in 214 (47.7%), and GG in 61 (13.6%) subjects, without any significant differences between cases and controls on both univariable (p=0.58) and multivariable logistic regression (each p>0.25). Furthermore, T309G MDM2 was not linked with T stage (p=0.75), N stage (p=0.37), M stage (p=0.94), grade (p=0.21), and subtype (p=0.55). There was, however, a statistically significant association of T309G MDM2 with CSS (p=0.022): patients with TT had significantly worse survival than GG/GT (p=0.009), while those with GT and GG had similar outcomes (p=0.92). The 5-year survival rate for patients with TT, GT, and GG was 69.5%, 84.5%, and 89.7%, respectively. On the multivariable analysis, T309G was identified as an independent prognostic factor. The T309G MDM2 polymorphism is an independent prognostic factor for patients with RCC, with the TT genotype being associated with worse prognosis. In this study, there were no significant associations with RCC risk and pathology.

MDM2 285G>C and 344T>A gene variants and their association with hepatocellular carcinoma: a Moroccan case-control study

BACKGROUND

MDM2 gene polymorphisms 285G/C and 344 T/A are two single nucleotide polymorphisms (SNPs) recently identified as important variants that could influence the expression of MDM2 gene through the modulation of transcription factors binding on the SNP309T/G. The 285C variant seems to present a geographically distinct distribution in humans and to be associated with a low cancer risk. In the present report, we studied the distribution of the three SNPs in a population with low liver cancer incidence.

METHODS

A group of 119 patients with hepatocellular carcinoma (HCC, 63.45 ± 12.59 year, 26-80) and another of 103 non-HCC controls (56 ± 10.82 year, 22-79) were enrolled to investigate association between MDM2 polymorphisms and susceptibility to develop HCC. The three studied SNPs (285G/C, 309 T/G and 344 T/A) were genotyped using polymerase chain reaction and sequencing techniques.

RESULTS

Genotypes and alleles distributions of the three studied polymorphisms of MDM2 were not significantly different between cases and controls. An increased risk of HCC development was found in case of 309G allele presence albeit without reaching the significance (29.8% vs 22.3%, OR = 1.48, 95% CI, 0.96-2.27, p = 0.073). In addition, neither 285C nor 344A MDM2 variants were significantly associated with an increased risk of HCC (p = 0.688 and p = 1 respectively). Remarkably, we found that the supposedly Caucasian-specific 285C variant was present in 1% of the Moroccan population.

CONCLUSIONS

This is the first study of the MDM2 SNP285G/C and SNP344T/A polymorphisms in association with HCC development. In contrast with previous studies, showing that females carrying SNP285C variant have a significantly reduced risk of developing breast, ovarian and endometrial cancer, no significant modulation of HCC risk was found in a North-African population.

Association between MDM2 SNP309 T>G and risk of gastric cancer: a meta-analysis

BACKGROUND

As a negative regulator of P53, MDM2 plays an important role in carcinogenesis; a polymorphism in its promoter region. SNP309 T>G, is known to increase the expression of MDM2, thus being considered related to higher susceptibility to neoplasia. However, no agreement has been achieved regarding its effects on gastric cancer.

METHODS

The present systematic meta-analysis was performed based on comprehensive literature search from Pubmed, Web of science and CBM databases.

RESULTS

It was suggested from 6 independent studies that the GG genotype is associated with a significantly increased risk of gastric cancer (Recessive: OR = 1.43, 95% CI = 1.08-1.91, P = 0.013), and subgroup analysis also confirmed the relationship (English publications-recessive model: OR = 1.45, 95% CI = 1.10-1.91, P = 0.009; Studies in China-recessive model: OR = 1.58, 95% CI = 1.08-2.30, P = 0.017). No publication bias was detected.

CONCLUSION

The meta-analysis indicated a significant inverse association between GG genotype carriage and elevated risk of gastric cancer. However, more studies and detailed information are needed to fully address the topic.

MDM2 SNP309T>G polymorphism and hepatocellular carcinoma risk: a meta-analysis

Case-control studies on the association between mouse double-minute 2 homolog (MDM2) SNP309T>G polymorphism and hepatocellular carcinoma have provided either controversial or inconclusive results. To clarify the effect of MDM2 SNP309T>G polymorphism on the risk of hepatocellular carcinoma, a meta-analysis of all case-control observational studies was performed. Pooled odds ratios (ORs) for various polymorphisms were estimated using random and fixed effects models. The Q-statistic was used to evaluate the homogeneity, and Egger and Begg tests were used to assess publication bias. Overall, the MDM2 SNP309T>G polymorphism was associated with a risk of hepatocellular carcinoma (OR = 0.68; 95% CI = 0.54-0.85 for allele contrast, p = 0.0005, phet = 0.004). The contrast of homozygotes and the recessive and dominant models produced the same pattern of results as the allele contrast. In the analysis stratified by ethnicity, significant associations were found in the Caucasian population in all of the genetic models. In addition, heterogeneity disappeared in subgroups of Caucasian subjects. Our pooled data suggest evidence for a major role of MDM2 SNP309T>G polymorphism in the carcinogenesis of hepatocellular carcinoma, especially among Caucasian populations.

TP53 and MDM2 gene polymorphisms, gene-gene interaction, and hepatocellular carcinoma risk: evidence from an updated meta-analysis

Background

The association between TP53 R72P and/or MDM2 SNP309 polymorphisms and hepatocellular carcinoma (HCC) risk has been widely reported, but results were inconsistent. To clarify the effects of these polymorphisms on HCC risk, an updated meta-analysis of all available studies was conducted.

Methods

Eligible articles were identified by search of databases including PubMed, Cochrane Library, EMBASE and Chinese Biomedical Literature database (CBM) for the period up to July 2013. Data were extracted by two independent authors and pooled odds ratio (OR) with 95% confidence interval (CI) was calculated. Metaregression and subgroup analyses were performed to identify the source of heterogeneity.

Results

Finally, a total of 10 studies including 2,243 cases and 3,615 controls were available for MDM2 SNP309 polymorphism and 14 studies containing 4,855 cases and 6,630 controls were included for TP53 R72P polymorphism. With respect to MDM2 SNP309 polymorphism, significantly increased HCC risk was found in the overall population. In subgroup analysis by ethnicity and hepatitis virus infection status, significantly increased HCC risk was found in Asians, Caucasians, Africans, and HCV positive patients. With respect to TP53 R72P polymorphism, no significant association with HCC risk was observed in the overall and subgroup analyses. In the MDM2 SNP309–TP53 R72P interaction analysis, we found that subjects with MDM2 309TT and TP53 Pro/Pro genotype, MDM2 309 TG and TP53 Arg/Pro genotype, and MDM2 309 GG and TP53 Pro/Pro genotype were associated with significantly increased risk of developing HCC as compared with the reference MDM2 309TT and TP53 Arg/Arg genotype.

Conclusions

We concluded that MDM2 SNP309 polymorphism may play an important role in the carcinogenesis of HCC. In addition, our findings further suggest that the combination of MDM2 SNP 309 and TP53 Arg72Pro genotypes confers higher risk to develop HCC. Further large and well-designed studies are needed to confirm this association.

Meta-analysis of associations between MDM2 SNP309 polymorphism and gastric cancer risk

Epidemiological studies have been conducted to evaluate genetic variations of murine double minute 2 (MDM2) SNP309 associated with the risk of gastric cancer (GC), although evidence remains conflicting. To gain a better understanding of this relationship, a meta-analysis was performed. Several electronic databases were searched up to February 2013, in order to identify relevant case-control studies. Seven published case-control studies with 2,199 cases and 3,201 controls were included. In the overall analysis, significant associations between the MDM2 SNP309 variant and GC risk were found for G vs. T alleles (OR=1.35; 95% CI, 1.24-1.47), GG vs. TT (OR=1.88; 95% CI, 1.59-2.24), recessive model (OR=1.71; 95% CI, 1.49-1.96). Furthermore, stratified by cancer site, significant associations were observed in gastric cardia cancer for all the models, although no significant association was found in any of the models among non-gastric cardia cancer, with the exception of the recessive model. In the subgroup analysis by source of control, MDM2 SNP309 was associated with increased GC risk for the hospital-based case-control (HCC) study for the GG vs. TT, recessive model and for the population-based case-control (PCC) study for the GG vs. TT, recessive model. Following stratification by gender and infection status of Helicobacter pylori (HP) for the recessive model, a significant association was found only in the HP-positive infected individuals. However, no statistically significant association was observed in males, females or the HP-negative infected individuals. In summary, the association between MDM2 SNP309 and GC risk was statistically significant, particularly in gastric cardia cancer for the HP-positive population group.

Progress in understanding role of diabetes mellitus in the development of hepatitis virus-related hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors. Hepatitis B or hepatitis C virus infection has been considered the most important etiologic factor for human HCC. Recently, it has been suggested that diabetes mellitus is a risk factor for HCC, and that insulin resistance as a critical component of diabetes mellitus pathogenesis may be involved in the occurrence of hepatitis virus-related HCC. Since IRS-1-Ser312 is a molecule that is involved in the pathogenesis of both hepatitis C virus and diabetes mellitus, IRS-1 or ROS may play a role in the development of HCC associated with diabetes mellitus and hepatitis B virus. Hence, diabetes mellitus and hepatitis virus not only are independent risk factors for HCC but also interact with each other to contribute to the development of this malignancy.

Human genetic variation and the risk of hepatocellular carcinoma development

Our understanding of the patho-physiology of hepatocellular carcinoma (HCC) is still much fragmented making difficult the improvement of the clinical outcome for the majority of HCC patients. Discovery of single nucleotide polymorphisms (SNPs) associated with individual susceptibility to HCC may enable the persons at risk to adapt their lifestyle and legitimate implementation by their doctors of surveillance programs facilitating early detection and subsequent management of the disease. To shed light on the influence of human genetic variation on HCC, we conducted a review of the meta-analyses of candidate SNPs and genome wide association studies (GWAS) performed for HCC by search of PubMed and Google Scholar databases. Genetic variations occurring in pathways historically considered as instrumental for liver tumorigenesis (TP53/MDM2, HLA, glutathione-S-transferases/cytochrome P540, TNFα/TGFβ, etc…) are discussed. An immense majority of the data has been produced in Eastern Asia (China, Japan, Korea). These meta-analyses indicate that the TP53, the MDM2 SNP309 G and the GSTT1 null genotype contribute to an increased risk of HCC both in Asians and Caucasians. Significant differences of odds ratios are, however, commonly observed between Eastern-Asians and other populations. Amazingly, GWAS studies performed so far exclusively with HCC patients from Eastern Asia produced drastically different outcomes pointing at unrelated biological pathways. The small magnitude of the risk associated with the genetic variants raises the question of their future utility as markers in clinical practice. An assessment of their impact on tumor progression (vascular invasion, metastases) remains, however, to be done and may prove to be more useful for clinicians. Finally, the evaluation of these variants is not available for various populations of the world and particularly for Subsaharan Africans who are especially affected by HCC.

Meta-analysis of associations between the MDM2-T309G polymorphism and prostate cancer risk

The mouse double minute 2 (MDM2) gene plays a key role in the p53 pathway, and the SNP 309T/G single- nucleotide polymorphism in the promoter region of MDM2 has been shown to be associated with increased risk of cancer. However, no consistent results were found concerning the relationships between the polymorphism and prostate cancer risk. This meta-analysis, covering 4 independent case-control studies, was conducted to better understand the association between MDM2-SNP T309G and prostate cancer risk focusing on overall and subgroup aspects. The analysis revealed, no matter what kind of genetic model was used, no significant association between MDM2-SNP T309G and prostate cancer risk in overall analysis (GT/TT: OR = 0.84, 95%CI = 0.60-1.19; GG/TT: OR = 0.69, 95%CI = 0.43-1.11; dominant model: OR = 0.81, 95%CI= 0.58-1.13; recessive model: OR = 1.23, 95%CI = 0.95-1.59). In subgroup analysis, the polymorphism seemed more likely to be a protective factor in Europeans (GG/TT: OR = 0.52, 95%CI = 0.31-0.87; recessive model: OR = 0.58, 95%CI = 0.36-0.95) than in Asian populations, and a protective effect of the polymorphism was also seen in hospital-based studies in all models (GT/TT: OR = 0.74, 95%CI = 0.57-0.97; GG/TT: OR = 0.55, 95%CI = 0.38-0.79; dominant model: OR = 0.69, 95%CI = 0.54-0.89; recessive model: OR = 0.70, 95%CI = 0.51-0.97). However, more primary studies with a larger number of samples are required to confirm our findings.

Association of type II diabetes mellitus with hepatocellular carcinoma occurrence--a case control study from Kathmandu Valley

OBJECTIVE

To assess associations of Type II DM with hepatocellular carcinoma occurrence in Nepal.

MATERIALS AND METHODS

This case control study was carried out using data retrieved from the register maintained in the Department of Biochemistry of Nepalese Army Institute of Health Sciences between 1st January, 2012, and 31st August, 2012. The variables collected were age, gender, HbA1c. All biochemical parameters were analyzed in the Central Laboratory of our hospital by standard validated methods. One way ANOVA was used to examine the statistical significant difference between groups with the LSD post-hoc test for comparison of means of case groups. Odds ratios (OR) were calculated using simple logistic-regression analysis.

RESULTS

Etiological factors for HCC were HBV, HCV, alcohol and cryptogenic cirrhosis. The highest age group belonged to the etiological category of HCV with a mean of 71.9 ± 3.6 (CI 69.3, 74.5) years and the lowest age group to the etiological category of HBV with 61.7 ± 5.3(CI 57.9, 65.5) years. The main imperative basis of HCC in present study was HCV (39.5%) and second most significant cause of HCC was alcohol (26%). Glycated hemoglobin was found to be more in males with HCC (7.9%) as compared to females (7.3%). The percentage of Type II diabetes mellitus was greater in HCC patients when compared to controls. This difference was statistically significant with an odd ratio of 4.63 (p<0.001).

CONCLUSION

Type II DM influences incidence, risk of recurrence, overall survival, and treatment-related complications in HCC patients.