Association of a miR-502-binding site single nucleotide polymorphism in the 3'-untranslated region of SET8 and the TP53 codon 72 polymorphism with cervical cancer in the Chinese population

CCND1, NOP14 and DNMT3B are involved in miR-502-5p-mediated inhibition of cell migration and proliferation in bladder cancer

OBJECTIVES

Downregulation of miR-502-5p has emerged as a critical factor in tumour progression in several cancers. Herein, we elucidated the role of miR-502-5p in bladder cancer.

MATERIALS AND METHODS

RT-qPCR was performed to examine the expression of miR-502-5p in bladder cancer. And DNA methylation analysis showed that epigenetic mechanisms may contribute to the downregulation of miR-502-5p. Then, wound-healing assay, transwell assay, colony formation assay, CCK8 assay and flow cytometry analysis were applied to evaluate the function of miR-502-5p in bladder cancer cell lines. Western blot was conducted to measure the protein levels of related genes. Furthermore, dual-luciferase reporter assay, in vivo tumorigenesis assay and immunohistochemical staining were also conducted as needed.

RESULTS

MiR-502-5p is frequently downregulated in BCa. Meanwhile, hypermethylation of CpG islands contributes to the downregulation of miR-502-5p. Functionally, overexpression of miR-502-5p inhibited cell proliferation and migration in vitro and repressed tumour growth in vivo. CCND1, DNMT3B and NOP14 were identified as direct targets of miR-502-5p. Interestingly, DNMT3B and miR-502-5p established a positive feedback loop in the regulation of bladder cancer. In addition, rescue experiments further validated the direct molecular interaction between miR-502-5p and its targets.

CONCLUSIONS

Our study proposed and demonstrated that the miR-502-5p-mediated regulatory network is critical in bladder cancer; this network may be useful in the development of more effective therapies against bladder cancer.

The association between rs16917496 T/C polymorphism of SET8 gene and cancer risk in Asian populations: a meta-analysis

Epidemiological studies have demonstrated close associations between SET8 rs16917496 T/C polymorphism and cancer risk, but the results of published studies were not consistent. We therefore performed this meta-analysis to explore the associations between rs16917496 T/C polymorphism and cancer risk. Five online databases were searched. Odds ratios (ORs) with a 95% confidence interval (CI) were calculated to assess the association between rs16917496 T/C polymorphism and cancer risk. In addition, heterogeneity, accumulative, sensitivity analysis, and publication bias were conducted to check the statistical power. Overall, 13 publications involving 5878 subjects were identified according to included criteria. No significant cancer risk was observed in genetic model of SET8 rs16917496 T/C polymorphism in Asian populations (C vs. T: OR = 1.04, 95%CI = 0.88–1.23, P = 0.63%; TC vs. TT: OR = 1.17, 95%CI = 0.96–1.24, P = 0.11%; CC vs. TT: OR = 0.90, 95%CI = 0.60–1.37, P = 0.63; TC+CC vs. TT: OR = 1.11, 95%CI = 0.90–1.38, P = 0.33; CC vs. TT+TC: OR = 0.92, 95%CI = 0.65–1.30, P = 0.63). Furthermore, similar associations were found in the subgroup analysis of race diversity, control design, genotyping methods, and different cancer types. In summary, our meta-analysis indicated that the SET8 rs16917496 T/C polymorphism may not play a critical role in cancer development in Asian populations.

Gene Expression Analysis of Two Epithelial-mesenchymal Transition-related Genes: Long Noncoding RNA-ATB and SETD8 in Gastric Cancer Tissues

Background

Cancer is the second cause of death after cardiovascular diseases worldwide. Tumor metastasis is the main cause of death in patients with cancer; therefore, unraveling the molecular mechanisms involved in metastasis is critical. Epithelial-mesenchymal transition (EMT) is believed to promote tumor metastasis. Based on the critical roles of long noncoding RNA-ATB (lncRNA-ATB) and SETD8 genes in cancer pathogenesis and EMT, in this study, we aimed to assess expression profile and clinicopathological relevance of these two genes in human gastric cancer.

Materials and Methods

Quantitative real-time polymerase chain reaction was performed to assess these gene expressions in gastric cancer tissues and various cell lines. The associations between these gene expressions and clinicopathological characteristics were also analyzed.

Results

Insignificant downregulation of lncRNA-ATB and significant upregulation of SETD8 in cancerous versus noncancerous gastric tissues were observed. Among different examined cell lines, all displayed both genes expression. Except for a significant inverse correlation between the expression levels of lncRNA-ATB and depth of invasion (T) and a direct association between SETD8 levels and advanced tumor grades, no significant association was found with other clinicopathological characteristics.

Conclusion

lncRNA-ATB and SETD8 genes may play a critical role in gastric cancer progression and may serve as potential diagnostic/prognostic biomarkers in cancer patients.

A functional single nucleotide polymorphism of SET8 is prognostic for breast cancer

A single-nucleotide polymorphism (SNP) locus rs16917496 (T > C) within the 3′-untranslated region (3′-UTR) of SET8 was associated with susceptibility in several malignancies including breast cancer. To further elucidate the prognostic relevance of this SNP in breast cancer, we conducted a clinical study as well as SET8 expression analysis in a cohort of 1,190 breast cancer patients. We demonstrated the expression levels of SET8 in TT genotype were higher than in CC genotypes, and high levels of SET8 were associated with poor survival. SET8 expression was significantly higher in breast tumor tissue than in paired adjacent normal tissue. In addition, survival analysis in 315 patients showed SNP rs16917496 was an independent prognostic factor of breast cancer outcome with TT genotype associated with poor survival compared with CC/CT genotypes. Thus, this SNP may serve as a genetic prognostic factor and a treatment target for breast cancer. Future studies are warranted.

Association of codon 72 polymorphism of p53 with the severity of cervical dysplasia, E6-T350G and HPV16 variant lineages in HPV16-infected women

Purpose. Polymorphic variability in the tumour-suppressor protein p53 at codon 72 has a considerable impact on cervical cancer development. The present study clarified the association between p53 codon 72 genotypes and the risk of cervical disease in Greek patients. We also examined whether the presence of specific p53 genotypes in combination with HPV16 variants or E6 T350G sequence variation can modify an individual's susceptibility to cervical disease.Methodology. The analysis of p53 genotypes was performed through PCR-RFLP. Sequence and phylogenetic tree analyses of the HPV16 E6 gene were also performed in order to identify HPV16 variants and T350G sequence variation.Results/Key findings. The outcomes of the present analysis revealed that women who are homozygous for the arg genotype are at a 4.17-fold higher risk of developing HPV16-associated HSIL+ (OR=4.17, 95 % CI:1.48-4.9, P=0.0049). Moreover, p53 arg/arg patients infected by an HPV16 prototype strain were associated with an increased risk of more severe lesions, while a significant relationship between the p53 arg/arg genotype in patients with T350G sequence variation and the risk of high-grade squamous intraepithelial lesions (HSILs) was revealed.Conclusion. The oncogenic potential of the virus is increased by the presence of the p53 arg/arg genotype in the Greek population in such a way that the specific protein interaction E6 (L83V)-p53 (Arg-72) can modify an individual's susceptibility to cervical disease.

Putative biomarkers for cervical cancer: SNVs, methylation and expression profiles

Cervical cancer is primarily caused by Human papillomavirus (HPV) infection, but other factors such as smoking habits, co-infections and genetic background, can also contribute to its development. Although this cancer is avoidable, it is the fourth most frequent type of cancer in females worldwide and can only be treated with chemotherapy and radical surgery. There is a need for biomarkers that will enable early diagnosis and targeted therapy for this type of cancer. Therefore, a systems biology pipeline was applied in order to identify potential biomarkers for cervical cancer, which show significant reports in three molecular aspects: DNA sequence variants, DNA methylation pattern and alterations in mRNA/protein expression levels. CDH1, CDKN2A, RB1 and TP53 genes were selected as putative biomarkers, being involved in metastasis, cell cycle regulation and tumour suppression. Other ten genes (CDH13, FHIT, PTEN, MLH1, TP73, CDKN1A, CACNA2D2, TERT, WIF1, APC) seemed to play a role in cervical cancer, but the lack of studies prevented their inclusion as possible biomarkers. Our results highlight the importance of these genes. However, further studies should be performed to elucidate the impact of DNA sequence variants and/or epigenetic deregulation and altered expression of these genes in cervical carcinogenesis and their potential as biomarkers for cervical cancer diagnosis and prognosis.

Serum microRNAs are non-invasive biomarkers for the presence and progression of subarachnoid haemorrhage

miRNAs are important regulators of translation and have been associated with the pathogenesis of a number of cardiovascular diseases including stroke and may be possible prognostic biomarkers. The purpose of the present study was to determine the expression levels of miRNAs in the sera of subarachnoid haemorrhage (SAH) patients and to evaluate their relationships with the severity and clinical outcome of SAH. Serum samples on day 3 after the onset of SAH were subjected to microarray analysis with Exqion miRCURY^TM LNA array and quantitative PCR analysis. Serum samples from SAH patients (n=60) and healthy controls (n=10) were subjected to quantitative PCR analysis. The severities and clinical outcomes of the SAH patients were evaluated with the WFNS grade and the Modified Rankin Scale (mRS). Three miRNAs, miR-502-5p, miR-1297 and miR-4320 were significantly up-regulated in the sera of SAH patients when compared with the healthy controls. The serum miR-502-5p and miR-1297 levels were significantly higher in the patients with severe SAH and a poor outcome than in those with mild SAH and a good outcome (P<0.05). The areas under the receiver operating characteristic (ROC) curves (AUCs) of miR-502-5p, miR-1297 and miR-4320 to distinguish the SAH patients from the healthy controls were 0.958 (P<0.001), 0.950 (P<0.001) and 0.843 (P<0.001) respectively. Taken together, these results indicate that miR-502-5p and miR-1297 are potentially valuable indicators of the diagnosis, severity and prognosis of SAH, and miR-4320 was a potentially valuable indicator of the diagnosis of SAH.

MiR-502/SET8 regulatory circuit in pathobiology of breast cancer

Our previous research and extensive epidemiological studies reproducibly demonstrated that miR-502 potentially targeted the expression of H4K20 methyltransferase SET8 in a wide spectrum of cancer. Yet, the direct targeting of SET8 by miR-502 has not been definitively proven. The clinical significance of the miR-502/SET8 regulatory circuit is also not clear. Here, we conducted cell-based experiments and clinical studies in a cohort of 279 breast cancer samples. We provide evidence that SET8 is a direct target of miR-502. Treatment with miR-502 or downregulation of SET8 suppressed cell proliferation and cell cycle, and reduced cell migration, invasion and EMT. Clinical analyses showed the miR-502 expression was lower in tumor tissues than in adjacent non-tumor tissues and had a significant inverse correlation with that of SET8. Furthermore, high expression of SET8 was significantly associated with poor overall survival (OS) and disease free survival (DFS) of breast cancer. The low expression ratio of miR-502 to SET8 mRNA was also significantly associated with poor OS. Thus, the miR-502/SET8 regulatory circuit emerges as a key regulator of the pathobiology of cancer and a focal point for possible therapeutic intervention.

Combined analysis of pri-miR-34b/c rs4938723 and TP53 Arg72Pro with cervical cancer risk

miR-34 family members can form a p53-miR-34 positive feedback loop and induce apoptosis, DNA repair, angiogenesis, and cell cycle arrest. We conducted a case-control study to examine whether two polymorphisms (i.e., rs4938723 in the promoter of pri-miR-34b/c and TP53 Arg72Pro) were linked to the carcinogenesis of cervical cancer among Chinese Han women. Genotypes of the two polymorphisms in 328 cervical cancer patients and 568 control subjects were determined by using a polymerase chain reaction-restriction fragment length polymorphism assay. We found a significantly increased cervical cancer risk in the pri-miR-34b/c rs4938723 under dominant and overdominant model (CT/CC vs. TT: adjusted OR = 1.34, 95 % CI = 1.01-1.77; CT vs. TT/CC: adjusted OR = 1.37, 95 % CI = 1.05-1.80, respectively). Increased cervical cancer risks were also found in the TP53 Arg72Pro under a heterozygous comparison and overdominant model (CG vs. GG: adjusted OR = 1.44, 95 % CI = 1.06-1.95; CG vs. GG/CC: adjusted OR = 1.47, 95 % CI = 1.12-1.94, respectively). Stratification analysis showed that patients carrying the pri-miR-34b/c rs4938723 CT genotype had a significantly increased risk for developing poorly differential status and clinical stage I. Moreover, increased cancer risks were observed for the TP53 Arg72Pro polymorphism in patients with poorly differential status, clinical stage II, and without lymph node metastasis. Combined analysis revealed that the genotypes of rs4938723 CT/CC and TP53 Arg72Pro CG/CC had an increased cervical cancer risk (OR = 2.21, 95 % CI = 1.38-3.53). These findings suggest that the pri-miR-34b/c rs4938723 and TP53 Arg72Pro polymorphisms may contribute to the genesis of cervical cancer.

Association between a p73 gene polymorphism and genetic susceptibility to non-small cell lung cancer in the South of China

BACKGROUND

This study aimed to identify any association between the p73 gene G4C14-to-A4T14 polymorphism and risk of non-small cell lung cancer (NSCLC) in the south of China.

MATERIALS AND METHODS

We genotyped the p73 gene polymorphism of peripheral blood DNA from 168 patients with NSCLC and 195 normal controls using HRM (high resolution melting) and PCR-CTPP (polymerase chain reaction with confronting two-pair primers).

RESULTS

The results of genotyping by HRM and PCR-CTPP were consistent with direct sequencing, the p73 genotype distribution in 168 lung cancer patients being as follows: GC/GC 101 cases (60.1%), GC/ AT 59 cases (35.1%), AT/AT 8 cases (4.8%). The carriers of AT/AT genotype had a significantly reduced risk of NSCLC (OR=0.370; 95%CI: 0.170-0.806; p=0.010) as compared with non-carriers. However, we found no relations between p73 genotypes and histological type (p=0.798, x2=0.452), tumor stage (p=0.806, x2=0.806), or lymph node metastasis (p=0.578, x2=1.098).

CONCLUSIONS

Our findings suggest that the p73 G4C14-to-A4T14 polymorphism may be a modifier of NSCLC susceptibility in the Chinese population.