Genetic variation in a microRNA-502 minding site in SET8 gene confers clinical outcome of non-small cell lung cancer in a Chinese population

Epi-miRNAs: Regulators of the Histone Modification Machinery in Human Cancer

Cancer is a leading cause of death and disability worldwide. Epigenetic deregulation is one of the most critical mechanisms in carcinogenesis and can be classified into effects on DNA methylation and histone modification. MicroRNAs are small noncoding RNAs involved in fine-tuning their target genes after transcription. Various microRNAs control the expression of histone modifiers and are involved in a variety of cancers. Therefore, overexpression or downregulation of microRNAs can alter cell fate and cause malignancies. In this review, we discuss the role of microRNAs in regulating the histone modification machinery in various cancers, with a focus on the histone-modifying enzymes such as acetylases, deacetylases, methyltransferases, demethylases, kinases, phosphatases, desumoylases, ubiquitinases, and deubiquitinases. Understanding of microRNA-related aberrations underlying histone modifiers in pathogenesis of different cancers can help identify novel therapeutic targets or early detection approaches that allow better management of patients or monitoring of treatment response.

Nuclear Pore Glycoprotein 62 Genetic Variant rs9523 is Associated with Clinical Outcomes of Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors in Lung Adenocarcinoma Patients

Introduction

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have represented the prototype of targeted therapy in NSCLC. Patients with EGFR-mutant lung adenocarcinoma extract an extraordinary clinical benefit from EGFR-TKIs. However, the extent and duration of these responses are heterogeneous, suggesting the existence of genetic modifiers affecting an individual’s response to TKIs. We investigated whether genetic variants in miRNA binding sites are associated with the clinical outcome of EGFR-TKIs in lung adenocarcinoma patients.

Methods

One hundred SNPs at miRNA binding sites in cancer-related genes were selected for the analysis using the crosslinking, ligation and sequencing of hybrids (CLASH) and CancerGenes database. qRT-PCR and luciferase assays were conducted to evaluate the functional relevance of the SNPs.

Results

NUP62 rs9523A>G were significantly associated with worse response to EGFR-TKIs, overall survival (OS), and progression-free survival (PFS). The other three SNPs (DVL2 rs2074216G>A, ARF1 rs11541557G>T, and UHRF1 rs2261988C>A) were significantly associated with worse OS and PFS. The rs9523A>G was significantly associated with decreased NUP62 expression in tumor tissues. In addition, a significantly decreased luciferase activity was noted in NUP62 rs9523 G allele compared to A allele.

Conclusion

Genetic variants in miRNA binding sites, especially NUP62 rs9523A>G, may be useful in predicting the clinical outcomes of EGFR-mutant lung adenocarcinoma patients treated with EGFR-TKIs.

Analysis of mutations in CDC27, CTBP2, HYDIN and KMT5A genes in carotid paragangliomas

Carotid paragangliomas (CPGLs) are rare neuroendocrine tumors that arise from paraganglionic tissue of the carotid body localizing at the bifurcation of carotid artery. These tumors are slowly growing, but occasionally they become aggressive and metastatic. Surgical treatment remains high-risk and extremely challenging; radiation and chemotherapy are poorly effective. The study of molecular pathogenesis of CPGLs will allow developing novel therapeutic approaches and revealing biomarkers. Previously, we performed the exome sequencing of 52 CPGLs and estimated mutational load (ML). Paired histologically normal tissues or blood were unavailable, so potentially germline mutations were excluded from the analysis with strong filtering conditions using 1000 Genomes Project and ExAC databases. In this work, ten genes (ZNF717, CDC27, FRG2C, FAM104B, CTBP2, HLA-DRB1, HYDIN, KMT5A, MUC3A, and PRSS3) characterized by the highest level of mutational load were analyzed. Using several prediction algorithms (SIFT, PolyPhen-2, MutationTaster, and LRT), potentially pathogenic mutations were identified in four genes (CDC27, CTBP2, HYDIN, and KMT5A). Many of these mutations occurred in the majority of cases, and their mutation type was checked using exome sequencing data of blood prepared with the same exome enrichment kit that was used for preparation of exome libraries from CPGLs. The majority of the mutations were germline that can apparently be associated with annotation errors in 1000 Genomes Pro ject and ExAC. However, part of the mutations identified in CDC27, CTBP2, HYDIN, and KMT5A remain potentially pathogenic, and there is a large body of data on the involvement of these genes in the formation and progression of other tumors. This allows considering CDC27, CTBP2, HYDIN, and KMT5A genes as potentially associated with CPGL pathogenesis and requires taking them into account in further investigations. Thus, there is a necessity to improve the methods for identification of cancer-asso ciated genes as well as pathogenic mutations. 

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.

A genetic variation in microRNA target site of ETS2 is associated with clinical outcomes of paclitaxel-cisplatin chemotherapy in non-small cell lung cancer

The present study was performed to investigate the association of single nucleotide polymorphisms (SNPs) located in the miRNA target sites with the clinical outcomes of first line paclitaxel-cisplatin chemotherapy in advanced NSCLC. Eighty SNPs in miRNA binding sites of cancer related genes selected from 18,500 miRNA:target bindings in crosslinking, ligation, and sequencing of hybrids (CLASH) data were investigated in 379 advanced NSCLC patients using a sequenom mass spectrometry-based genotype assay. qRT-PCR and luciferase assay were conducted to examine functional relevance of potentially functional SNPs in miRNA binding sites. Of the 80 SNPs analyzed, 16 SNPs were significantly associated with the clinical outcomes after chemotherapy. Among these, ANAPC1 rs3814026C>T, ETS2 rs461155A>G, SORBS1 rs7081076C>A and POLR2A rs2071504C>T could predict both chemotherapy response and survival. Notably, ETS2 rs461155A>G was significantly associated with decreased ETS2 mRNA expression in both tumor and paired normal lung tissues (Ptrend = 4 × 10⁻⁷, and 3 × 10⁻⁴, respectively). Consistently, a decreased expression of the reporter gene for the G allele of rs461155 compared with the A allele was observed by luciferase assay. These findings suggest that the four SNPs, especially ETS2 rs461155A>G, could be used as biomarkers predicting the clinical outcomes of NSCLC patients treated with first-line paclitaxel-cisplatin chemotherapy.

Association between polymorphisms in microRNA target sites and survival in early-stage non-small cell lung cancer

A high‐throughput mapping method of RNA–RNA interactions by crosslinking, ligation, and sequencing of hybrids (CLASH) can not only provide information about canonical but also non‐canonical interactions. We evaluated the associations between variants in microRNA target sites using CLASH data and survival outcomes of 782 early‐stage non‐small cell lung cancer (NSCLC) patients who underwent curative surgical resection. Among the 100 variants studied, two variants showed significant association with survival outcomes. The POLR2A rs2071504 C > T variant was associated with poor overall and disease‐free survival under a dominant model (hazard ratio [HR] 1.42, 95% confidence interval [CI] 1.08–1.88; P = 0.01 and HR 1.34, 95% CI 1.08–1.67; P = 0.01, respectively). Patients carrying the NR2F6 rs2288539 TT genotype showed significantly better overall survival than those with the NR2F6 rs2288539 CC or CT genotypes (HR 0.13, 95% CI 0.02–0.90; P = 0.04). These findings suggest that POLR2A rs2071504 C > T and NR2F6 rs2288539 C > T can influence prognosis in early‐stage NSCLC patients.

Polymorphism (rs16917496) at the miR-502 Binding Site of the Lysine Methyltransferase 5A (SET8) and Its Correlation with Colorectal Cancer in Iranians

Background:

One of the gene expression regulatory mechanisms is mediated by small noncoding RNAs called microRNA (miRNA). They interact with a recognition sequence located mostly in 3’-untranslated regions (3’-UTRs) of mRNAs. Polymorphisms in miRNAs recognition sequences could affect gene expression which in turn may alter disease susceptibility. SET8, a member of the SET domain-containing methyltransferase, acts in a variety of biological processes such as genomic stability. Here, we report correlation of rs16917496 polymorphism, located in the recognition sequence of miR-502 within 3’-UTR of SET8, with colorectal cancer (CRC) in Iranians.

Materials and Methods:

One hundred and seventy CRC patients and 170 noncancer counterparts were recruited in this case–control study. Genotyping of rs16917496 was performed using polymerase chain reaction-restriction fragment length polymorphism method.

Results:

There was no significant association of rs16917496 with CRC in population under study (P value for genotype and allele distribution were >0.05). However, stratification analysis based on smoking status revealed that TT+TC genotypes of SET8 rs16917496 are strongly associated with increased risk of CRC (odds ratio: 5.8, 95% confidence interval: 1.37–24.34, P - 0.005) in smoker subgroup.

Conclusion:

Correlation of rs16917496 T allele with CRC in smokers is emphasizing the importance of individuals’ genotype in the recruitment of adverse health hazards of smoking more profoundly for certain people compared to others.

MiRNAs and miRNA Polymorphisms Modify Drug Response

Differences in expression of drug response-related genes contribute to inter-individual variation in drugs’ biological effects. MicroRNAs (miRNAs) are small noncoding RNAs emerging as new players in epigenetic regulation of gene expression at post-transcriptional level. MiRNAs regulate the expression of genes involved in drug metabolism, drug transportation, drug targets and downstream signal molecules directly or indirectly. MiRNA polymorphisms, the genetic variations affecting miRNA expression and/or miRNA-mRNA interaction, provide a new insight into the understanding of inter-individual difference in drug response. Here, we provide an overview of the recent progress in miRNAs mediated regulation of biotransformation enzymes, drug transporters, and nuclear receptors. We also describe the implications of miRNA polymorphisms in cancer chemotherapy response.

The emerging role of lysine methyltransferase SETD8 in human diseases

SETD8/SET8/Pr-SET7/KMT5A is the only known lysine methyltransferase (KMT) that monomethylates lysine 20 of histone H4 (H4K20) in vivo. Lysine residues of non-histone proteins including proliferating cell nuclear antigen (PCNA) and p53 are also monomethylated. As a consequence, the methyltransferase activity of the enzyme is implicated in many essential cellular processes including DNA replication, DNA damage response, transcription modulation, and cell cycle regulation. This review aims to provide an overview of the roles of SETD8 in physiological and pathological pathways and to discuss the progress made to date in inhibiting the activity of SETD8 by small molecules, with an emphasis on their discovery, selectivity over other methyltransferases and cellular activity.

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.

Effects of CYP3A5 genetic polymorphism and smoking on the prognosis of non-small-cell lung cancer

Objective

We aimed to explore the impacts of the rs776746 polymorphism in the CYP3A5 gene and smoking on the prognosis of non-small-cell lung cancer (NSCLC).

Materials and methods

Our study enrolled 104 early NSCLC patients undergoing surgery and 107 advanced NSCLC patients undergoing chemotherapy, hospitalized between December 2009 and December 2012 at the First Affiliated Hospital of Liaoning Medical University. All subjects with complete follow-up data were pathologically diagnosed. The rs776746 polymorphism and different genotypes (*1/*1, *1/*3, and *3/*3) were identified by polymerase chain-reaction restriction fragment-length polymorphism.

Results

Clinical response to chemotherapy in NSCLC patients with *1/*1 + *1/*3 genotypes were significantly worse than in those with the *3/*3 genotype (17.78% vs 56.45%, P<0.001), and after Bonferroni adjustment, the differences still showed significance (P_c<0.01). The mortality risk of NSCLC patients undergoing chemotherapy with the *3/*3 genotype was 0.617 times those with *1/*1 + *1/*3 genotypes (relative risk [RR] 0.617, 95% confidence interval [CI] 0.402–0.948; P=0.028), while the mortality risk of smoking patients was 1.743 times greater than that of nonsmoker patients (RR 1.743, 95% CI 1.133–2.679; P=0.042). Furthermore, a 3.087-fold mortality risk was found in NSCLC patients undergoing surgery with the *3/*3 genotype compared with those with *1/*1 + *1/*3 genotypes (RR 3.087, 95% CI 1.197–7.961; P=0.020). In NSCLC patients undergoing surgery, the mortality risk of smokers was 1.896 times greater than nonsmokers (RR 1.896, 95% CI 1.040–3.455; P=0.037).

Conclusion

Our study demonstrated that the CYP3A5 rs776746 polymorphism and smoking may influence the prognosis of NSCLC patients undergoing chemotherapy and surgery.

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

OBJECTIVE

This study was conducted to identify whether polymorphic variants of set domain-containing protein 8 (SET8) and tumor protein p53 (TP53) codon 72, either independently or jointly, might be associated with increased risk for cervical cancer.

METHODS

We genotyped SET8 and TP53 codon 72 polymorphisms of peripheral blood DNA from 114 cervical cancer patients and 200 controls using the polymerase chain reaction- restriction fragment length polymorphism (PCR-RFLP) and direct DNA sequencing.

RESULTS

The frequency of SET8 CC (odds ratios (OR) = 2.717, 95% CI=1.436-5.141) or TP53 GG (OR=2.168, 95% CI=1.149-4.089) genotype was associated with an increased risk of cervical cancer on comparison with the SET8 TT or TP53 CC genotypes, respectively. In additional, interaction between the SET8 and TP53 polymorphisms increased the risk of cervical cancer in a synergistic manner, with the OR being 9.913 (95% CI=2.028-48.459) for subjects carrying both SET8 CC and TP53 GG genotypes.

CONCLUSION

These data suggest that there are significant associations between the miR-502-binding site SNP in the 3'-UTR of SET8 and the TP53 codon 72 polymorphism with cervical cancer in Chinese, and there is a gene-gene interaction.

A genetic variation in microRNA target site of KRT81 gene is associated with survival in early-stage non-small-cell lung cancer

BACKGROUND

MicroRNAs (miRNAs) have a key role in carcinogenesis through negative regulation of their target genes. Therefore, genetic variations in miRNAs or their target sites may affect miRNA-mRNA interactions, thereby result in altered expression of target genes. This study was conducted to investigate the associations between single-nucleotide polymorphisms (SNP) located in the miRNA target sites (poly-miRTSs) and survival of patients with early-stage non-small-cell lung cancer (NSCLC).

METHODS

Using public SNP database and miRNA target sites prediction program, 354 poly-miRTSs were selected for genotyping. Among these, 154 SNPs applicable to Sequenom's MassARRAY platform were investigated in 357 patients. A replication study was carried out on an independent patient population (n = 479). Renilla luciferase assay and reverse transcription-polymerase chain reaction were conducted to examine functional relevance of potentially functional poly-miRTSs.

RESULTS

Of the 154 SNPs analyzed in a discovery set, 14 SNPs were significantly associated with survival outcomes. Among these, KRT81 rs3660G>C was found to be associated with survival outcomes in the validation cohort. In the combined analysis, patients with the rs3660 GC + CC genotype had a significantly better overall survival compared with those with GG genotype [adjusted hazard ratio (aHR) for OS, 0.65; 95% confidence interval (CI) 0.50-0.85; P = 0.001]. An increased expression of the reporter gene for the C allele of rs3660 compared with the G allele was observed by luciferase assay. Consistently, the C allele was associated with higher relative expression level of KRT81 in tumor tissues.

CONCLUSION

The rs3660G>C affects KRT81 expression and thus influences survival in early-stage NSCLC. The analysis of the rs3660G>C polymorphism may be useful to identify patients at high risk of a poor disease outcome.

A functional variant at miR-34a binding site in toll-like receptor 4 gene alters susceptibility to hepatocellular carcinoma in a Chinese Han population

Toll-like receptor 4 (TLR4) plays a key role in prompting the innate or immediate response. A growing body of evidence suggests that genetic variants of TLR4 gene were associated with the development of cancers. This study aimed to investigate the relationship of a functional variant (rs1057317) at microRNA-34a (miR-34a) binding site in toll-like receptor 4 gene and the risk of hepatocellular carcinoma. A single center-based case-control study was conducted. In this study, the polymerase chain reaction (PCR) and direct sequencing were used to genotype sequence variants of TLR4 in 426 hepatocellular carcinoma cases and 438 controls. The modification of rs1057317 on the binding of hsa-miR-34a to TLR4 messenger RNA (mRNA) was measured by luciferase activity assay. Individuals carrying the AA genotypes for the rs1057317 were associated significantly with increased risk of hepatocellular carcinoma comparing with those carrying wild-type homozygous CC genotypes (adjusted odds ratio [OR] by sex and age, from 1.116 to 2.452, P = 0.013). The activity of the reporter vector was lower in the reporter vector carrying C allele than the reporter vector carrying A allele. Furthermore, the expression of TLR4 was detected in the peripheral blood mononucleated cell of hepatocellular carcinoma (HCC) patients, suggesting that mRNA and protein levels of TLR4 might be associated with SNP rs1057317. Collectively, these results suggested that the risk of hepatocellular carcinoma was associated with a functional variant at miR-34a binding site in toll-like receptor 4 gene. miR-34a/TLR4 axis may play an important role in the development of hepatocellular carcinoma.

miR-30b, down-regulated in gastric cancer, promotes apoptosis and suppresses tumor growth by targeting plasminogen activator inhibitor-1

Background

Gastric cancer is one of the most common malignant diseases worldwide. Emerging evidence has shown that microRNAs (miRNAs) are associated with tumor development and progression. Our previous studies have revealed that H. pylori infection was able to induce the altered expression of miR-30b in gastric epithelial cells. However, little is known about the potential role of miR-30b in gastric cancer.

Methods

We analyzed the expression of miR-30b in gastric cancer cell lines and human gastric cancer tissues. We examined the effect of miR-30b mimics on the apoptosis of gastric cancer cells in vitro by flow cytometry (FCM) and caspase-3/7 activity assays. Nude mouse xenograft model was used to determine whether miR-30b is involved in tumorigenesis of gastric cancer. The target of miR-30b was identified by bioinformatics analysis, luciferase assay and Western blot. Finally, we performed the correlation analysis between miR-30b and its target expression in gastric cancer.

Results

miR-30b was significantly down-regulated in gastric cancer cells and human gastric cancer tissues. Enforced expression of miR-30b promoted the apoptosis of gastric cancer cells in vitro, and miR-30b could significantly inhibit tumorigenicity of gastric cancer by increasing the apoptosis proportion of cancer cells in vivo. Moreover, plasminogen activator inhibitor-1 (PAI-1) was identified as the potential target of miR-30b, and miR-30b level was inversely correlated with PAI-1 expression in gastric cancer. In addition, silencing of PAI-1 was able to phenocopy the effect of miR-30b overexpression on apoptosis regulation of cancer cells, and overexpression of PAI-1 could suppressed the effect of promoting cell apoptosis by miR-30b, indicating PAI-1 is potentially involved in miR-30b-induced apoptosis on cancer cells.

Conclusion

miR-30b may function as a novel tumor suppressor gene in gastric cancer by targeting PAI-1 and regulating the apoptosis of cancer cells. miR-30b could serve as a potential biomarker and therapeutic target against gastric cancer.

MicroRNA binding site polymorphisms as biomarkers in cancer management and research

MicroRNAs (miRNAs) are important regulators of eukaryotic gene expression. They have been implicated in a broad range of biological processes, and miRNA-related genetic alterations probably underlie several human diseases. Single nucleotide polymorphisms of transcripts may modulate the posttranscriptional regulation of gene expression by miRNAs and explain interindividual variability in cancer risk and in chemotherapy response. On the basis of recent association studies published in the literature, the present review mainly summarizes the potential role of miRNAs as molecular biomarkers for disease susceptibility, diagnosis, prognosis, and drug-response prediction in tumors. Many clues suggest a role for polymorphisms within the 3' untranslated regions of KRAS rs61764370, SET8 rs16917496, and MDM4 rs4245739 as SNPs in miRNA binding sites highly promising in the biology of human cancer. However, more studies are needed to better characterize the composite spectrum of genetic determinants for future use of markers in risk prediction and clinical management of diseases, heading toward personalized medicine.

Association of functional polymorphism at the miR-502-binding site in the 3' untranslated region of the SETD8 gene with risk of childhood acute lymphoblastic leukemia, a preliminary report

MicroRNAs (miRNAs), a class of non-coding RNAs, bind to the 3' untranslated regions (UTRs) of mRNAs, where they interfere with translation of genes and are implicated in the pathogenesis of diverse diseases. In the present study, we evaluate the impact of rs16917496 polymorphism within the miR-502 miRNA seed region at the 3'UTR of SEDT8 on childhood acute lymphoblastic leukemia (ALL). This case-control study was done on 75 ALL and 115 healthy children. Genotyping of rs16917496 C/T polymorphism was performed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The results showed that CT as well as CT + TT decreased the risk of ALL in comparison with CC genotype (odds ratio (OR) = 0.29, 95 % confidence intervals (95 % CI) = 0.11-0.78, P = 0.014 and OR = 0.31, 95 % CI = 0.12-0.82, P = 0.016, respectively). Our results demonstrated that SETD8 rs16917496 C/T polymorphism was associated with decreased risk of developing pediatric ALL in Zahedan, southeast Iran. Larger studies with different ethnicities are desired to validate our findings.

Interferon alpha-inducible protein 27 promotes epithelial-mesenchymal transition and induces ovarian tumorigenicity and stemness

BACKGROUND

Interferon alpha-inducible protein 27 (IFI27) is an interferon alpha-inducible protein, which was found to be upregulated in some cancers, such as breast cancer, squamous cell carcinoma, hepatocellular carcinoma, and serous ovarian carcinoma. However, the role of IFI27 in ovarian cancer remains to be elucidated. This study was designed to investigate the role of IFI27 in ovarian cancer tumorigenicity.

MATERIALS AND METHODS

The expression of IFI27 was examined in ovarian cancer tissues and cell lines by real time quantitative reverse transcription polymerase chain reaction and immunohistochemistry. The cell migration and invasion was investigated by wound healing and transwell invasion assay. The epithelial-mesenchymal transition markers were detected by Western blotting and the stemness was evaluated by sphere formation. The tumor growth was examined in the athymic mice model.

RESULTS

We found that IFI27 is overexpressed in ovarian cancer and associated with patients' survival. Interestingly, we further observed that the expression of IFI27 was associated with the expression of mesenchymal marker vimentin in ovarian cancer. Overexpression of IFI27 induces epithelial-mesenchymal transition and promotes epithelial ovarian cancer cells migration and invasion, tumorigenicity, stemness, and drug resistance. Moreover, overexpression of IFI27 is associated with loss of miR-502 in ovarian cancer. Reexpression of miR-502 inhibits IFI27-induced tumorigenicity, migration, and drug resistance.

CONCLUSIONS

These data suggested that IFI27 may be a potential target for developing novel diagnosis strategies and therapeutic interventions.