Lymph node metastasis of gastric cancer is associated with the interaction between poly (ADP-ribose) polymerase 1 and matrix metallopeptidase 2

Genetic polymorphisms as potential pharmacogenetic biomarkers for platinum-based chemotherapy in non-small cell lung cancer

Platinum-based chemotherapy (PBC) is a widely used treatment for various solid tumors, including non-small cell lung cancer (NSCLC). However, its efficacy is often compromised by the emergence of drug resistance in patients. There is growing evidence that genetic variations may influence the susceptibility of NSCLC patients to develop resistance to PBC. Here, we provide a comprehensive overview of the mechanisms underlying platinum drug resistance and highlight the important role that genetic polymorphisms play in this process. This paper discussed the genetic variants that regulate DNA repair, cellular movement, drug transport, metabolic processing, and immune response, with a focus on their effects on response to PBC. The potential applications of these genetic polymorphisms as predictive indicators in clinical practice are explored, as are the challenges associated with their implementation.

Correlation of Poly (adenosine diphosphate[ADP]-ribose) Polymerase Expression and Prognosis in Ovarian Cancer: A Systematic Review and Meta-analysis

PURPOSE

This meta-analysis evaluated the correlation between poly (adenosine diphosphate [ADP]-ribose) polymerase (PARP) expression and prognosis in patients with ovarian cancer.

METHODS

Eligible studies were extracted from the electronic databases of PubMed, Web of Science, and EMBASE until 1 August 2019. The included studies investigated the correlation between PARP expression and clinical outcomes in patients with ovarian cancer. Clinical outcomes are overall survival (OS) and progression free survival (PFS). The clinical data of patients, such as clinicopathologic characteristics and survival, were analyzed. The language was limited to English, and studies conducted at the cellular level, animal studies, and non-original research were excluded. The odds ratios (ORs) and hazard ratios (HRs) with 95% confidence intervals (CIs) were used for this meta-analysis.

RESULTS

A total of 9 eligible studies involving 1230 patients were included in our meta-analysis. Based on the analysis, higher PARP expression was correlated with worse overall survival [OS] (HR,1.64; 95% CI, 1.08-2.49; P = 0.020) in the univariate analysis, whereas results from multivariate analysis indicated that PARP overexpression wasn't statistically associated with worse OS (HR, 1.36; 95% CI, 0.98-1.90; P = 0.069). Moreover, the pooled results revealed that patients with PARP overexpression were not associated with worse histologic grade (OR,2.22; 95% CI, 0.98-5.02; P = 0.06).

CONCLUSION

PARP overexpression maybe associated with poor prognosis and survival in patients with ovarian cancer. The patients with PARP over expression were not tended to have a worse histologic grade. Findings require further validation.

PARP1 rs1136410 (A/G) polymorphism is associated with early age of onset of gallbladder cancer

OBJECTIVES

Evaluation of the association of PARP1 rs1136410 (A/G) polymorphism with gallbladder cancer susceptibility and its prognosis in the Indian population of eastern Uttar Pradesh and western Bihar.

METHODS

PARP1 rs1136410 was genotyped by PCR-RFLP and its association with the prognosis of gallbladder cancer patients were analyzed using Kaplan-Meier plot and log-rank tests.

RESULTS

Our results demonstrate that minor allele G is more frequent in gallbladder cancer patients than controls. The frequencies of minor allele G and GG genotype are significantly associated with increased risk of gallbladder cancer. Our data suggest that the minor allele G and homozygous genotype GG are significant predisposing factors for the early age of onset of gallbladder cancer. Similarly, women patients having AG and GG genotypes demonstrate an increased risk of gallbladder cancer. The risk group genotypes (AG + GG) are significantly more frequent in patients with thick gallbladder wall, with jaundice and with the presence of lymph node than in patients with normal gallbladder wall thickness, without jaundice and absence of lymph node involvement. Survival analysis data suggest that patients with risk group genotype (AG + GG) presenting jaundice have shorter overall survival.

CONCLUSION

Our study suggests that the minor allele G of PARP1 rs1136410 (A/G) is a predisposing factor for gallbladder carcinogenesis and is significantly associated with early onset of the disease. Interestingly, the minor allele G is significantly more frequent in the patients with jaundice, lymph node metastasis and gallbladder wall thickness.

Association of T2285C polymorphism in PARP1 gene coding region with its expression, activity and NSCLC risk along with prognosis

Poly (ADP-ribose) polymerase-1(PARP1), a DNA repair gene, is the crucial player in the maintenance of genome integrity. T2285C polymorphism in coding region of PARP1 has been reported to be associated with susceptibility to tumors. We explored the relation and mechanism of T2285C polymorphism of PARP1 to its expression and activity along with risk and prognosis in NSCLC. mRNA expression was measured using qRT-PCR assay or collected from TCGA dataset. Protein expression was examined with immunoblotting assay. Genotypes were determined by PCR-RFLP and sequencing approaches. PARP1 activity was determined with enzyme activity assay. Regulation of SIRT7 to PARP1 were determined by over-expression and small interference experiment. Association of PARP1 T2285C polymorphism with NSCLC risk was evaluated via multiple logistic regression analysis. Comparison of treatment response and PFS of NSCLC patients among different genotypes or regimens was made by Chi-square test. Results indicated that mRNA and protein expression of PARP1 dramatically increased in NSCLC tissues in comparison to paired para-carcinoma tissues (P<0.05). TC/CC mutant genotypes were associated with markedly enhanced PARP1 mRNA level compared with TT genotype (P=0.011). No significant difference was discovered in PARP1 protein expression among TT, TC or CC genotypes (P>0.05). Subjects with variant allele C had higher risk of NSCLC in comparison to allele T carriers [odds ratio (OR) =1.560; P=0.000]. NSCLC patients carrying mutational TC or CC genotypes were correlated with unfavorable response to platinum-based chemotherapy (TT vs.TC vs.CC, P=0.010), and shorter PFS compared to TT genotype (TT vs.TC vs.CC, P=0.009). T2285C mutation of PARP1 resulted in the enhancement of its mRNA, but the decrease of enzyme activity in tumor cell. Overexpression of SIRT7 attenuated PARP1 expression and activity. These findings suggest the variant allele C of T2285C polymorphism of PARP1 linked to an increase of NSCLC risk, and unfavorable efficacy and prognosis of NSCLC patients with platinum-based chemotherapy, which might be associated with enhancement of its mRNA expression and the diminishment of activity. Identification of PARP1 T2285C polymorphism and mRNA expression may be the promising way for the individualized treatment of NSCLC.

PARP1 rs1136410 Val762Ala contributes to an increased risk of overall cancer in the East Asian population: a meta-analysis

Objectives

To investigate the association between poly(ADP-ribose) polymerase 1 (PARP1) rs1136410 Val762Ala and cancer risk in Asian populations, as published findings remain controversial.

Methods

The PubMed and EMBASE databases were searched, and references of identified studies and reviews were screened, to find relevant studies. Meta-analyses were performed to evaluate the association between PARP1 rs1136410 Val762Ala and cancer risk, reported as odds ratio (OR) and 95% confidence interval (CI).

Results

A total of 24 studies with 8 926 cases and 15 295 controls were included. Overall, a significant association was found between PARP1 rs1136410 Val762Ala and cancer risk in East Asians (homozygous: OR 1.19, 95% CI 1.06, 1.35; heterozygous: OR 1.10, 95% CI 1.04, 1.17; recessive: OR 1.13, 95% CI 1.02, 1.25; dominant: OR 1.13, 95% CI 1.06, 1.19; and allele comparison: OR 1.09, 95% CI 1.03, 1.15). Stratification analyses by race and cancer type revealed similar results for gastric cancer among the Chinese population.

Conclusion

The findings suggest that PARP1 rs1136410 Val762Ala may be significantly associated with an increased cancer risk in Asians, particularly the Chinese population.

The PARP Enzyme Family and the Hallmarks of Cancer Part 2: Hallmarks Related to Cancer Host Interactions

Poly (ADP-ribose) polymerases (PARPs) modify target proteins with a single ADP-ribose unit or with a poly (ADP-ribose) (PAR) polymer. PARP inhibitors (PARPis) recently became clinically available for the treatment of BRCA1/2 deficient tumors via the synthetic lethality paradigm. This personalized treatment primarily targets DNA damage-responsive PARPs (PARP1-3). However, the biological roles of PARP family member enzymes are broad; therefore, the effects of PARPis should be viewed in a much wider context, which includes complex effects on all known hallmarks of cancer. In the companion paper (part 1) to this review, we presented the fundamental roles of PARPs in intrinsic cancer cell hallmarks, such as uncontrolled proliferation, evasion of growth suppressors, cell death resistance, genome instability, replicative immortality, and reprogrammed metabolism. In the second part of this review, we present evidence linking PARPs to cancer-associated inflammation, anti-cancer immune response, invasion, and metastasis. A comprehensive overview of the roles of PARPs can facilitate the identification of novel cancer treatment opportunities and barriers limiting the efficacy of PARPi compounds.

Identification of key genes and associated pathways in KIT/PDGFRA wild‑type gastrointestinal stromal tumors through bioinformatics analysis

Gastrointestinal stromal tumors (GISTs) are the most common type of mesenchymal tumor in the gastrointestinal tract. The present study aimed to identify the potential candidate biomarkers that may be involved in the pathogenesis and progression of v-kit Hardy-Zuckerman 4 feline sarcoma viral oncogene homolog (KIT)/platelet-derived growth factor receptor α (PDGFRA) wild-type GISTs. A joint bioinformatics analysis was performed to identify the differentially expressed genes (DEGs) in wild-type GIST samples compared with KIT/PDGFRA mutant GIST samples. Gene Ontology function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of DEGs was conducted using Database for Annotation, Visualization and Integrated Discovery and KEGG Orthology-Based Annotation System (KOBAS) online tools, respectively. Protein-protein interaction (PPI) networks of the DEGs were constructed using Search Tool for the Retrieval of Interacting Genes online tool and Cytoscape, and divided into sub-networks using the Molecular Complex Detection (MCODE) plug-in. Furthermore, enrichment analysis of DEGs in the modules was analyzed with KOBAS. In total, 546 DEGs were identified, including 238 upregulated genes primarily enriched in ‘cell adhesion’, ‘biological adhesion’, ‘cell-cell signaling’, ‘PI3K-Akt signaling pathway’ and ‘ECM-receptor interaction’, while the 308 downregulated genes were predominantly involved in ‘inflammatory response’, ‘sterol metabolic process’ and ‘fatty acid metabolic process’, ‘small GTPase mediated signal transduction’, ‘cAMP signaling pathway’ and ‘proteoglycans in cancer’. A total of 25 hub genes were obtained and four modules were mined from the PPI network, and sub-networks also revealed these genes were primarily involved in significant pathways, including ‘PI3K-Akt signaling pathway’, ‘proteoglycans in cancer’, ‘pathways in cancer’, ‘Rap1 signaling pathway’, ‘ECM-receptor interaction’, ‘phospholipase D signaling pathway’, ‘ras signaling pathway’ and ‘cGMP-PKG signaling pathway’. These results suggested that several key hub DEGs may serve as potential candidate biomarkers for wild-type GISTs, including phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit γ, insulin like growth factor 1 receptor, hepatocyte growth factor, thrombospondin 1, Erb-B2 receptor tyrosine kinase 2 and matrix metallopeptidase 2. However, further experiments are required to confirm these results.

Gene-gene interactions in gastrointestinal cancer susceptibility

Cancer arises from complex, multi-layer interactions between diverse genetic and environmental factors. Genetic studies have identified multiple loci associated with tumor susceptibility. However, little is known about how germline polymorphisms interact with one another and with somatic mutations within a tumor to mediate acquisition of cancer traits. Here, we survey recent studies showing gene-gene interactions, also known as epistases, affecting genetic susceptibility in colorectal, gastric and esophageal cancers. We also catalog epistasis types and cancer hallmarks with respect to the interacting genes. A total of 22 gene variation pairs displayed all levels of statistical epistasis, including synergistic, redundant, suppressive and co-suppressive interactions. Five genes primarily involved in base excision repair formed a linear topology in the interaction network, MUTYH-OGG1-XRCC1-PARP1-MMP2, and three genes in mTOR cell-proliferation pathway formed another linear network, PRKAG2-RPS6KB1-PIK3CA. Discrete pairwise epistasis was also found in nucleotide excision repair, detoxification, proliferation, TP53, TGF-β and other pathways. We propose that three modes of biological interaction underlie the molecular mechanisms for statistical epistasis. The direct binding, linear pathway and convergence modes can exhibit any level of statistical epistasis in susceptibility to gastrointestinal cancers, and this is likely true for other complex diseases as well. This review highlights the link between cancer hallmarks and susceptibility genes.

The association of matrix metalloproteinase-9 promoter polymorphisms with gastric cancer risk: a meta-analysis

Purpose

A variety of studies have observed that the single nucleotide polymorphisms (SNPs) matrix metalloproteinase-9 (MMP-9) gene may be associated with the risk of gastric cancer(GC), and a cytosine (C) to thymine (T) mutation at the -1562 site of the MMP-9 gene promoter is reported to be closely related to the susceptibility. However, because of the conflicting results of these studies, we undertook a systematic meta-analysis to assess the association between the SNPs and the risk of gastric cancer.

Materials and Methods

A computerised literature search was conducted within the databases of PubMed, EMBASE, and ISI Web of Knowledge for studies on the genetic association of MMP-9-1562C/T and gastric cancer published from 2004 to 2015. The pooled odds ratio (OR) and 95% confidence intervals (CI) were estimated for each genotype using the dominant, recessive, co-dominant, and allelic models of the matrix metalloproteinase 9.

Results

Our analysis indicated a significant association of MMP-9-1562C/T with gastric cancer (dominant model [CT+TT/CC]: OR = 1.121, 95% CI = 0.965–1.304; recessive model [CC+CT/TT]: OR = 1.663, 95% CI = 1.148–2.408; co-dominant model [TT/CC]: OR = 1.666, 95% CI = 1.127–2.461; [CT/CC]: OR = 1.078, 95% CI = 0.923–1.259; allelic model [T/C]: OR = 1.150, 95% CI =1.014–1.304).

Conclusions

Our meta-analysis results demonstrated that MMP-9-1562C/T promoter polymorphisms increase the risk of developing gastric cancer.

PARP6 acts as a tumor suppressor via downregulating Survivin expression in colorectal cancer

Poly (ADP-ribose) polymerases (PARPs) are enzymes that transfer ADP-ribose groups to target proteins and are involved in a variety of biological processes. PARP6 is a novel member, and our previous findings suggest that PARP6 may act as a tumor suppressor via suppressing cell cycle progression. However, it is still unclear that PARP6 function besides growth suppression in colorectal cancer (CRC). In this study, we examined tumor suppressive roles of PAPR6 in CRC cells both in vitro and in vivo. We found that PARP6 inhibited colony formation, invasion and migration as well as cell proliferation. Moreover, ectopic overexpression of PARP6 decreased Survivin expression, which acts as an oncogene and is involved in apoptosis and mitosis. We confirmed the inverse correlation between PARP6 and Survivin expression in CRC cases by immunohistochemistry. Importantly, CRC cases with downregulation of PARP6 and upregulation of Survivin showed poor prognosis. In summary, PARP6 acts as a tumor suppressor via downregulating Survivin expression in CRC. PARP6 can be a novel diagnostic and therapeutic target together with Survivin for CRC.

Grhl2 reduces invasion and migration through inhibition of TGFβ-induced EMT in gastric cancer

Metastasis is one of the typical features of malignancy that significantly increases cancer-related mortality. Recent studies have shown that epithelial-mesenchymal transition (EMT) is closely related to the invasion and migration of cancer cells. Grainyhead-like 2 (Grhl2), a transcription factor, has been reported to be associated with several tumor processes including EMT. In the previous study, we have reported that Grhl2 functioned as a tumor suppressor in proliferation and apoptosis of gastric cancer. Here we aim to explore the effects of Grhl2 on invasion and migration of gastric cancer and further clarify its possible underlying mechanisms. As a result, in both SGC7901 and MKN45 cells, Grhl2 overexpression significantly inhibited the ability of invasion and migration. In addition, preliminary experiments showed that Grhl2 reduces the protein expression of matrix metalloproteinase-2, -7 and -9 (MMP-2, MMP-7 and MMP-9). Most importantly, Grhl2 antagonizes transforming growth factor-β (TGFβ)-induced EMT, and inhibition of TGFβ signaling pathways can restore Grhl2 expression. Finally, the results of subcutaneous xenograft model indicated that Grhl2 suppresses the growth of gastric cancer and reverses EMT process in vivo. Meanwhile, the metastatic tumor model further confirmed the inhibition of Grhl2 on metastasis of gastric cancer. Taken together, our findings proved that Grhl2, functioned as a tumor suppressor, reduces the invasion and migration through inhibition of TGFβ-induced EMT in gastric cancer.

PARP-1 may be involved in angiogenesis in epithelial ovarian cancer

Poly (ADP-ribose) polymerase 1 (PARP-1) is involved in DNA repair and has been implicated in chemoresistance. The present study investigated whether PARP-1 promotes angiogenesis in ovarian cancer. PARP-1 and vascular endothelial growth factor A (VEGF-A) expression and CD34⁺ microvascular density (MVD) were assessed using immunohistochemistry in 60 human epithelial ovarian cancer specimens. PARP-1 was stably knocked-down in SKOV3 cells using a specific small interfering RNA (siRNA); angiogenic capacity was assessed using the human umbilical vein endothelial cell (HUVEC) tubule formation assay; and PARP-1 and VEGF-A expression were examined by reverse transcription-quantitative polymerase chain reaction, western blotting and ELISA. PARP-1 was found to be expressed in 73.3% (44/60) of the human epithelial ovarian cancer specimens and was significantly associated with VEGF-A, MVD, tumor size, histological grade and lymphatic metastasis (P<0.05). Compared with cells transfected with a negative control siRNA, knockdown of PARP-1 significantly suppressed the ability of SKOV3 cell-conditioned media to promote HUVEC tubule formation on Matrigel in vitro. Knockdown of PARP-1 in SKOV3 cells also significantly reduced VEGF-A mRNA and protein expression and secretion. In summary, PARP-1 is overexpressed and may enhance angiogenesis in epithelial ovarian cancer by upregulating VEGF-A.

High PARP-1 expression is associated with tumor invasion and poor prognosis in gastric cancer

Poly (adenosine diphosphate-ribose) polymerase 1 (PARP-1) was previously demonstrated to be overexpressed in numerous malignant tumors and associated with invasiveness and poor prognosis. However, the expression of the PARP-1 protein in gastric cancer and its association with clinical outcomes requires further investigation. In the present study, the expression of PARP-1 in 564 gastric cancer tissues and 335 tumor-adjacent control tissues is investigated, using tissue microarray-based immunohistochemistry. PARP-1 expression levels were demonstrated to be significantly higher in gastric cancer tissue samples, as compared with control tissue samples. In gastric cancer, high PARP-1 expression levels were significantly associated with Helicobacter pylori (H. pylori) infection (P=0.032), decreased differentiation (P<0.001), increased depth of invasion (P=0.037), presence of lymphatic invasion (P<0.001), presence of lymph node metastasis (P<0.001), and advanced tumor-node-metastasis (TNM) stage (P=0.015). High PARP-1 expression levels were associated with a significantly shorter overall survival rate (P<0.001) and disease-free survival rate (P=0.001) in patients with gastric cancer, particularly a subset of patients with H. pylori infection or an advanced TNM stage. In addition, univariate analysis indicated that PARP-1 high expression levels were significantly associated with a poor prognosis in gastric cancer. These results suggest that PARP-1 expression may be involved in the progression and prognosis of gastric cancer, particularly H. pylori-positive or advanced-stage gastric cancer.

Lentivirus-mediated inhibition of USP39 suppresses the growth of gastric cancer cells via PARP activation

Gastric cancer (GC) is the second most common cause of cancer-associated mortality worldwide. Ubiquitin-specific peptidase 39 (USP39) has important roles in mRNA processing and has been reported to be involved in the growth of breast cancer cells. However, the roles of USP39 in GC have remained to be investigated, which was the aim of the present study. A lentivirus expressing short hairpin RNA targeting USP39 was constructed and transfected into MGC80‑3 cells. Suppression of USP39 expression significantly decreased the proliferation and colony forming ability of MGC80‑3 cells as indicated by an MTT and a clonogenic assay, respectively. In addition, flow cytometric cell cycle analysis revealed that depression of USP39 induced G2/M‑phase arrest, while an intracellular signaling array showed that the cleavage of PARP at Asp214 was increased following USP39 knockdown. These results suggested that USP39 is involved in the proliferation of GCs and may be utilized as a molecular target for GC therapy.

Relationship between single-nucleotide polymorphism of matrix metalloproteinase-2 gene and colorectal cancer and gastric cancer susceptibility: a meta-analysis

Background

Recently, the published data on the association between matrix metalloproteinase-2 (MMP-2) (C-1306T) polymorphism and colorectal cancer (CRC) and gastric cancer (GC) (gastrointestinal cancer) risk remained controversial. The aim of this study is to investigate the relationship between the risk of CRC and GC and single-nucleotide polymorphism of MMP-2(C-1306T).

Methods

Medline, Embase, Science Citation Index, and PubMed were thoroughly searched to identify relevant studies. Odds ratio (OR) with 95% confidence interval (CI) was used to assess the strength of the association.

Results

We performed a meta-analysis of 14 studies including 642 cases and 692 controls for CRC and 1,936 cases and 3,490 controls for GC. The result indicates that there is significant relationship between MMP-2(C-1306T) polymorphism and CRC risk in recessive model and codominant model (TT vs CC/CT: OR: 2.39, 95% CI: 1.30–4.37, P=0.005; TT vs CC: OR: 2.36, 95% CI: 1.29–4.34, P=0.006). In subgroup analysis according to ethnicity, significant associations were found in Caucasians (TT vs CC/CT: OR: 2.87, 95% CI: 1.43–5.78, P=0.003; TT vs CC: OR: 2.86, 95% CI: 1.41–5.80, P=0.003), but we did not find significant evidence with GC in all genetic models, and in stratified analysis according to ethnicity, no significant risk was found in the subgroup too.

Conclusion

This meta-analysis considered that the MMP-2(C-1306T) polymorphism is a risk factor for CRC susceptibility, especially in Caucasians, but it does not support any relationship to GC, and further studies are needed to explore the association.

Expression of cluster of differentiation-95 and relevant signaling molecules in liver cancer

The present study investigated the protein expression levels of cluster of differentiation (CD)95, caspase‑8, caspase‑3 and poly(ADP‑ribose) polymerase 1 (PARP1) in liver cancer and its association with clinical pathological parameters. The results demonstrated that the expression of CD95 correlated with histological differentiation, liver cirrhosis, lymph node metastasis and distant metastasis (P<0.05), however, no correlations with gender, age, quantity of tumor nodules or T stage were observed (P>0.05). The expression of CD95 was upregulated using a plasmid, which led to an increase in the expression levels of caspase‑8 and caspase‑3 and a decrease in the expression of PARP1. Upregulation of CD95 also promoted the apoptosis of the liver cancer cells. These results indicated that CD95 was associated with liver cancer and promoted the apoptosis of liver cancer cells by caspase‑8, caspase‑3 and PARP1.

Meta-analysis of associations between four polymorphisms in the matrix metalloproteinases gene and gastric cancer risk

BACKGROUND

Matrix metalloproteinases (MMPs) play important roles in pathogenesis and development of cancer. Recently, many studies have show associations between polymorphisms in the promoter regions of MMPs and risk of gastric cancer. The present meta-analysis was conducted in order to investigate the potential association between four polymorphisms in the MMP gene and gastric cancer risk.

METHODS

A computerized literature search was conducted in databases of Med-line, Embase, Science Citation Index and PubMed till June 2013 for any MMP genetic association study of gastric cancer. Odds ratios (ORs) and 95 % confidence intervals (CIs) were estimated for each gene under dominant and recessive models, and heterogeneity between studies was assessed using the Q test and I2 value. Overall and subgroup analyses according to ethnicity were carried out with Stata 12.0.

RESULTS

14 reports covering 8,146 patients (2,980 in the case group and 5,166 in the control group) were included in the present meta-analysis. We found that the MMP-7 (-181A>G) polymorphism increased the gastric cancer risk in therecessive model (GG vs. AA/AG, OR=1.768, 95% CI =1.153-2.712). For MMP2 ?1306 C>T, MMP1-1607 1G/2G, and MMP9?1 562 C>T, there were no associations between these polymorphisms and the risk of gastric cancer under dominant or recessive models.

CONCLUSION

This meta-analysis suggested that the MMP7-181 A>G polymorphism may contribute to gastric cancer susceptibility. More studies are needed, especially in Europeans, in the future.

Association between the poly(ADP-ribose) polymerase-1 gene polymorphism and advanced pelvic organ prolapse

OBJECTIVE

Apoptotic cell death, probably induced by oxidative stress, contributes to the development of pelvic organ prolapse. Because poly(ADP-ribose) polymerase-1 is an important mediator of cellular response to oxidative stress, genetic variations in the poly(ADP-ribose) polymerase-1 gene may play a role in the pathogenesis of pelvic organ prolapse. This study aimed to determine the association between advanced pelvic organ prolapse and Val762Ala polymorphism in the poly(ADP-ribose) polymerase-1 gene.

METHODS

A total of 340 women were enrolled in the study. The pelvic organ prolapse group consisted of 185 women with stage III or IV pelvic organ prolapse, whereas the control group consisted of 155 postmenopausal women with stage 0 or I pelvic organ prolapse who visited the hospital for treatment of benign gynecologic disease or routine gynecologic checkup. Genotyping of the poly(ADP-ribose) polymerase-1 Val762Ala polymorphism was performed by real-time polymerase chain reaction analysis using a TaqMan assay.

RESULTS

Genotype distribution in the pelvic organ prolapse group was different from that in the control group (P = 0.024). Furthermore, C-allele frequency was lower in the pelvic organ prolapse group than in the control group (P = 0.029). Women with the CC genotype had a 0.461-fold lower risk of developing advanced pelvic organ prolapse than women with the TT genotype (95% CI, 0.245-0.870; P = 0.017), and women with the C-allele had a 0.716-fold lower risk of developing advanced pelvic organ prolapse than women with the T-allele (95% CI, 0.527-0.973; P = 0.033).

CONCLUSIONS

These findings suggest that the poly(ADP-ribose) polymerase-1 Val762Ala polymorphism is associated with a decreased risk of advanced pelvic organ prolapse.

Correlation of MMP-2 gene polymorphism C-1306T with susceptibility to gastric cancer: A meta-analysis

AIM: To explore the correlation between the matrix metalloproteinase-2 (MMP-2) gene promoter single nucleotide polymorphism C-1306T (rs243865) and susceptibility to gastric cancer (GC).

METHODS: A computer search of MEDLINE (1966-2013), the Cochrance Library Database (Issue 12, 2013), EMBASE(1980-2013), CINAHL (1982-2013), Web of Science (1945-2013), Chinese Biomedical Literature Database (CBM) (1982-2013), Wanfang (1998-2013) and CNKI (1915-2013) was performed to retrieve relevant studies. Meta-analysis was performed using STATA12.0 statistical software. Risk ratio (RR) and 95% confidence interval (CI) were calculated.

RESULTS: Seven independent case-control studies with a total of 1687 GC patients and 2253 healthy subjects met the inclusion criteria. The findings of the meta-analysis demonstrated that MMP-2 C-1306T polymorphism may be significantly associated with an increased risk of GC [allele model: RR = (1.05, 95%CI: 1.03-1.08), P < 0.001; dominant model: RR = (1.01, 95%CI: 1.00-1.02), P = 0.046]. Results of subgroup analysis by ethnicity showed a significant positive correlation between MMP-2 C-1306T polymorphism and GC risk among Asians [RR = (1.06, 95%CI: 1.04-1.08), P < 0.001], but not among Caucasians (P > 0.05). Further subgroup analyses according to the detection method, genotype, and sample size found that there were significant correlations (P < 0.05 for all) between them in most subgroups.

CONCLUSION: Our findings confirm the hypothesis that MMP-2 C-1306T polymorphism may contribute to an increased risk of GC, especially among Asian populations.

Association between the PARP1 Val762Ala polymorphism and cancer risk: evidence from 43 studies

BACKGROUND

Poly (ADP-ribose) polymerase-1 (PARP-1) plays critical roles in the detection and repair of damaged DNA, as well as cell proliferation and death. Numerous studies have examined the associations between PARP1 Val762Ala (rs1136410 T>C) polymorphism and cancer susceptibility; nevertheless, the findings from different research groups remain controversial.

METHODS

We searched literatures from MEDLINE, EMBASE and CBM pertaining to such associations, and then calculated pooled odds ratio (OR) and 95% confidence interval (CI) by using random-effects model. The false-positive report probability (FPRP) analysis was used to confirm the validity of significant findings. Moreover, potential effects of rs1136410 variants on PARP1 mRNA expression were analyzed for three ethnicities by combining data from HapMap (genotype) and SNPexp (mRNA expression).

RESULTS

The final meta-analysis incorporated 43 studies, consisting of 17,351 cases and 22,401 controls. Overall, our results did not suggest significant associations between Ala variant (Ala/Ala or Ala/Val genotype) and cancer risk. However, further stratification analysis showed significantly increased risk for gastric cancer (Ala/Ala vs. Val/Val: OR = 1.56, 95% CI = 1.01-2.42, Ala/Val vs. Val/Val: OR = 1.34, 95% CI = 1.14-1.58, dominant model: OR = 1.41, 95% CI = 1.21-1.65 and Ala vs. Val: OR = 1.29, 95% CI = 1.07-1.55). On the contrary, decreased risk for brain tumor (Ala/Val vs. Val/Val: OR = 0.77, 95% CI = 0.68-0.87, dominant model: OR = 0.77, 95% CI = 0.68-0.87 and Ala vs. Val: OR = 0.82, 95% CI = 0.74-0.91). Additionally, we found that the Ala carriers had a significantly increased risk in all models for Asians. Our mRNA expression data provided further biological evidence to consolidate this finding.

CONCLUSIONS

Despite some limitations, this meta-analysis found evidence for an association between the PAPR1 Val762Ala and cancer susceptibility within gastric cancer, brain tumor and Asian subgroups.

Association between promoters polymorphisms of matrix metalloproteinases and risk of digestive cancers: a meta-analysis

PURPOSE

A variety of studies have been performed to elucidate the polymorphisms in promoter regions of matrix metalloproteinases (MMPs) associated with the risk of digestive cancers, and yet, results remain conflicting and heterogeneous. Thus, we undertook a systematic meta-analysis to determine the genetic susceptibility of MMPs to digestive cancers.

METHODS

A computerized literature search was conducted in databases of PubMed, Embase, and ISI Web of Knowledge till October 2012 for any MMP genetic association study in oral squamous, gastric, esophageal, and colorectal carcinomas. Odds ratios (OR) and 95 % confidence interval (CI) were estimated for each gene under dominant and recessive models, and the heterogeneity between studies was assessed using Q test and I (2) value. Overall and subgroup analysis according to anatomical sites and ethnicity was carried out. Statistical analysis was performed with Review Manager 5.0.

RESULTS

A total of 40 eligible publications with 68 comparisons were included in this study. For MMP1 nt-1607, individuals with 2G state could increase risk of digestive cancers in total analysis (dominant: OR = 1.31, 95 % CI = 1.16-1.48, P < 0.00001; recessive: OR = 1.29, 95 % CI = 1.11-1.50, P = 0.0009). In the subgroup of tumor sites, significant associations were also observed in esophageal cancer and colorectal cancer under both genetic models. For MMP2 nt-1306, CT or TT carriers performed significant protection against digestive cancer in the dominant model (OR = 0.69, 95 % CI = 0.55-0.85, P = 0.0007) of the overall. In the subgroup analysis, significant association was found in esophageal cancer, with borderline effects in gastric cancer and oral squamous cell carcinoma. For MMP7 -181 A/G, significant association was observed under two genetic models in the overall (dominant: OR = 1.26, 95 % CI = 1.10-1.43, P = 0.0009; recessive: OR = 1.33, 95 % CI = 1.11-1.60, P = 0.002) and in the individual cancer subgroup of esophageal cancer and gastric cancer. For MMP9 -1,562 C/T, a borderline effect was found with digestive cancers in the total and stratified analysis of the colorectal cancer under dominant model. No association was observed in either the overall or subgroup analysis for MMP3 -1,171 5A/6A.

CONCLUSIONS

Our meta-analysis demonstrated the fact that polymorphisms in promoter regions of MMP genes might be related to the susceptibility of digestive cancers, with cancer development for MMP1 and MMP7, and a protection against cancer for MMP2 and MMP9. Further evidences with adequate sample sizes need to be conducted.

Activated T cell exosomes promote tumor invasion via Fas signaling pathway

Activated T cells release bioactive Fas ligand (FasL) in exosomes, which subsequently induce self-apoptosis of T cells. However, their potential effects on cell apoptosis in tumors are still unknown. In this study, we purified exosomes expressing FasL from activated CD8(+) T cell from OT-I mice and found that activated T cell exosomes had little effect on apoptosis and proliferation of tumor cells but promoted the invasion of B16 and 3LL cancer cells in vitro via the Fas/FasL pathway. Activated T cell exosomes increased the amount of cellular FLICE inhibitory proteins and subsequently activated the ERK and NF-κB pathways, which subsequently increased MMP9 expression in the B16 murine melanoma cells. In a tumor-invasive model in vivo, we observed that the activated T cell exosomes promoted the migration of B16 tumor cells to lung. Interestingly, pretreatment with FasL mAb significantly reduced the migration of B16 tumor cells to lung. Furthermore, CD8 and FasL double-positive exosomes from tumor mice, but not normal mice, also increased the expression of MMP9 and promoted the invasive ability of B16 murine melanoma and 3LL lung cancer cells. In conclusion, our results indicate that activated T cell exosomes promote melanoma and lung cancer cell metastasis by increasing the expression of MMP9 via Fas signaling, revealing a new mechanism of tumor immune escape.