miR-485-5p binding site SNP rs8752 in HPGD gene is associated with breast cancer risk

Genetic Foundation of Prostaglandin Metabolism Influences Patent Ductus Arteriosus Closure in Extremely Low Birth Weight Infants

OBJECTIVE

 Prostaglandins (PGs) play a major role in maintaining patency of the ductal arteriosus (DA). Pulmonary 15-hydroxyprostaglandin dehydrogenase (PGDH), which is ecoded by the hydroxyprostaglandin dehydrogenase (HPGD) gene, is the primary enzyme responsible for PG breakdown. Animal studies have shown HPGD-knockout mice have significantly higher prostaglandin E2 levels and no ductal remodeling. Functional variants of the HPGD gene that alter PG breakdown have not been studied in preterm infants with patent ductus arteriosus (PDA).

STUDY DESIGN

 This was an observational cohort study including extreme low birth weight (ELBW) infants classified as having spontaneous, medical, or procedural (transcatheter or surgical ligation) closure of their DA. Urine prostaglandin E metabolite (PGEM) levels were measured in ELBW infants following ibuprofen treatment using competitive ELISA. HPGD genetic variants rs8752, rs2612656, and rs9312555 were analyzed. Kruskal-Wallis, Fisher's exact, chi square, logistic regression, and Wilcoxon signed-rank tests were used; p < 0.05 was considered significant.

RESULTS

 Infants in the procedural closure group had a younger gestational age (GA). The incidence of spontaneous closure or medical closure was higher compared to procedural closure in the presence of any minor allele of rs8752 (67 and 27%, respectively; p = 0.01), when adjusted for GA and gender. Haplotype analysis of three variants of HPGD revealed differences when comparing the spontaneous and medical closure group to the procedural group (p < 0.05). Urinary PGEM levels dropped significantly in those ELBW infants who responded to ibuprofen (p = 0.003) in contrast to those who did not respond (p = 0.5).

CONCLUSION

 There was a different genotype distribution for the rs8752 genetic variant of the HPGD gene-as it relates to the mode of treatment for ELBW infants with PDA. We speculate that medical management in the presence of this variant facilitated additional PG breakdown, significantly abrogating the need for procedural closure. Additionally, differences in genotype and haplotype distributions implicate a specific HPGD genetic foundation for DA closure in ELBW infants.

KEY POINTS

· PGs and their metabolism play a major role in PDA patency or closure.. · Genetic variants of the HPGD gene influence mode of treatment of PDA in ELBW infants.. · ELBW infants with PDA that responded to medical closure had significantly decreased urine PGEM levels..

Integrated bioinformatics and statistical approaches to explore molecular biomarkers for breast cancer diagnosis, prognosis and therapies

Integrated bioinformatics and statistical approaches are now playing the vital role in identifying potential molecular biomarkers more accurately in presence of huge number of alternatives for disease diagnosis, prognosis and therapies by reducing time and cost compared to the wet-lab based experimental procedures. Breast cancer (BC) is one of the leading causes of cancer related deaths for women worldwide. Several dry-lab and wet-lab based studies have identified different sets of molecular biomarkers for BC. But they did not compare their results to each other so much either computationally or experimentally. In this study, an attempt was made to propose a set of molecular biomarkers that might be more effective for BC diagnosis, prognosis and therapies, by using the integrated bioinformatics and statistical approaches. At first, we identified 190 differentially expressed genes (DEGs) between BC and control samples by using the statistical LIMMA approach. Then we identified 13 DEGs (AKR1C1, IRF9, OAS1, OAS3, SLCO2A1, NT5E, NQO1, ANGPT1, FN1, ATF6B, HPGD, BCL11A, and TP53INP1) as the key genes (KGs) by protein-protein interaction (PPI) network analysis. Then we investigated the pathogenetic processes of DEGs highlighting KGs by GO terms and KEGG pathway enrichment analysis. Moreover, we disclosed the transcriptional and post-transcriptional regulatory factors of KGs by their interaction network analysis with the transcription factors (TFs) and micro-RNAs. Both supervised and unsupervised learning's including multivariate survival analysis results confirmed the strong prognostic power of the proposed KGs. Finally, we suggested KGs-guided computationally more effective seven candidate drugs (NVP-BHG712, Nilotinib, GSK2126458, YM201636, TG-02, CX-5461, AP-24534) compared to other published drugs by cross-validation with the state-of-the-art alternatives top-ranked independent receptor proteins. Thus, our findings might be played a vital role in breast cancer diagnosis, prognosis and therapies.

The tumor suppressor MIR139 is silenced by POLR2M to promote AML oncogenesis

MIR139 is a tumor suppressor and is commonly silenced in acute myeloid leukemia (AML). However, the tumor-suppressing activities of miR-139 and molecular mechanisms of MIR139-silencing remain largely unknown. Here, we studied the poorly prognostic MLL-AF9 fusion protein-expressing AML. We show that MLL-AF9 expression in hematopoietic precursors caused epigenetic silencing of MIR139, whereas overexpression of MIR139 inhibited in vitro and in vivo AML outgrowth. We identified novel miR-139 targets that mediate the tumor-suppressing activities of miR-139 in MLL-AF9 AML. We revealed that two enhancer regions control MIR139 expression and found that the polycomb repressive complex 2 (PRC2) downstream of MLL-AF9 epigenetically silenced MIR139 in AML. Finally, a genome-wide CRISPR-Cas9 knockout screen revealed RNA Polymerase 2 Subunit M (POLR2M) as a novel MIR139-regulatory factor. Our findings elucidate the molecular control of tumor suppressor MIR139 and reveal a role for POLR2M in the MIR139-silencing mechanism, downstream of MLL-AF9 and PRC2 in AML. In addition, we confirmed these findings in human AML cell lines with different oncogenic aberrations, suggesting that this is a more common oncogenic mechanism in AML. Our results may pave the way for new targeted therapy in AML.

The Unique Biology behind the Early Onset of Breast Cancer

Breast cancer commonly affects women of older age; however, in developing countries, up to 20% of breast cancer cases present in young women (younger than 40 years as defined by oncology literature). Breast cancer in young women is often defined to be aggressive in nature, usually of high histological grade at the time of diagnosis and negative for endocrine receptors with poor overall survival rate. Several researchers have attributed this aggressive nature to a hidden unique biology. However, findings in this aspect remain controversial. Thus, in this article, we aimed to review published work addressing somatic mutations, chromosome copy number variants, single nucleotide polymorphisms, differential gene expression, microRNAs and gene methylation profile of early-onset breast cancer, as well as its altered pathways resulting from those aberrations. Distinct biology behind early-onset of breast cancer was clear among estrogen receptor-positive and sporadic cases. However, further research is needed to determine and validate specific novel markers, which may help in customizing therapy for this group of patients.

The emerging roles of non-coding competing endogenous RNA in hepatocellular carcinoma

Accumulating evidence has emerged revealing that noncoding RNAs (ncRNAs) play essential roles in the occurrence and development of hepatocellular carcinoma (HCC). However, the complicated regulatory interactions among various ncRNAs in the development of HCC are not entirely understood. The newly discovered mechanism of competing endogenous RNAs (ceRNAs) uncovered regulatory interactions among different varieties of RNAs. In recent years, a growing number of studies have suggested that ncRNAs, including long ncRNAs, circular RNAs and pseudogenes, play major roles in the biological functions of the ceRNA network in HCC. These ncRNAs can share microRNA response elements to affect microRNA affinity with target RNAs, thus regulating gene expression at the transcriptional level and both physiological and pathological processes. The ncRNAs that function as ceRNAs are involved in diverse biological processes in HCC cells, such as tumor cell proliferation, epithelial-mesenchymal transition, invasion, metastasis and chemoresistance. Based on these findings, ncRNAs that act as ceRNAs may be promising candidates for clinical diagnosis and treatments. In this review, we discuss the mechanisms and research methods of ceRNA networks. We also reviewed the recent advances in studying the roles of ncRNAs as ceRNAs in HCC and highlight possible directions and possibilities of ceRNAs as diagnostic biomarkers or therapeutic targets. Finally, the limitations, gaps in knowledge and opportunities for future research are also discussed.

microRNA-related single-nucleotide polymorphisms and breast cancer

Breast cancer, as the most common cancer in women which affects patients both mentally and physically, requires great attention in many areas and many levels as this cancer is known to be multifactorial. Single-stranded molecules called microRNAs with near 22 nucleotides are seen to act in central dogma of molecular biology by inhibiting the translation process; it is demonstrated that any alteration in their sequence especially single-nucleotide polymorphisms (SNPs) may lead into increasing the breast cancer risk. miR-SNPs are considered to be the potential biomarkers for early detection of breast cancer. As a result, this review documents the well-known miR-SNPs that are known to be associated with breast cancer. In this regard, two principals were discussed: (a) SNPs in the target genes of microRNAs and the alteration in gene expression due to this phenomenon; (b) changes based on the SNPs in the microRNA coding region and the impact on their interaction with target messenger RNA.

CLDN10 single nucleotide polymorphism rs1325774 alters the risk of breast cancer in south chinese women

Breast cancer is one of the most widespread malignancies in females, and the incidence rate has been increasing in recent years in the world. Genetic factors play an important role in the occurrence of breast cancer. Our study aimed to investigate the relationship between single nucleotide polymorphisms (SNPs) of claudin 10 (CLDN10) (rs1325774, rs7333503, rs3751334) and breast cancer and the clinical characteristics of patients.A total of 104 patients with breast cancer and 118 healthy controls were recruited in our study between 2013 and 2015. The SNPscan system was used for genotyping. Demographic information, health status, anthropometric parameters and clinical data were considered in analysis. Statistical analysis of the data was carried out using the Student t test, the Chi-square test (X2) or Fisher exact test and unconditional logistic regression analysis. The Gene Expression Profiling Interactive Analyses application (GEPIA) was used to analysis the expression of CLDN10 in breast cancer tissues and normal samples.The polymorphism of rs1325774 was significantly associated with an increased risk of breast cancer (T/G vs T/T: OR = 2.073, 95% CI = 1.095-3.927, P = .025). After adjusting for age, the association remained statically significant (T/G vs T/T: OR = 2.067, 95% CI = 1.070-3.867, P = .026). Furthermore, harbouring G allele in rs1325774 position was significantly associated with increased risk of breast cancer (OR = 1.993, 95% CI = 1.107-3.589, P = .022). However, no significant association among rs7333503, rs3751334, and breast cancer. The expression level of CLDN10 was reduced in breast cancer tissues compared with normal breast tissues according to the analysis of The Cancer Genome Atlas (TCGA) data through GEPIA.Our results suggest that the polymorphism of rs1325774 associate with increase the breast cancer risk. No significant relationship between rs1325774 polymorphism and clinical as well as pathological characteristics in patients.

Identification of alterations in the nucleotide sequence of the chromatin remodeling gene PBRM1 in clear cell renal cell carcinoma patients

Kidney cancer is a heterogeneous group of malignant tumors, the vast majority of which are renal cell carcinomas (RCC) of various morphological types, of which the most common is the clear cell renal cell carcinoma (ccRCC). Particular attention in the carcinogenesis of the ccRCC is given to a number of tumor suppressor genes located on the short arm of the third chromosome. One of these genes, which are inactivated in the case of ccRCC is the PBRM1 gene encoding the PBAF SWI/SNF subunit of the chromatin remodeling complex, BAF180. The PBRM1 gene is located on the short arm of the third chromosome in the 3p21 region near the von Hippel-Lindau gene (VHL), the mutation in which is the main event in the occurrence of ccRCC. The aim of our investigation is identification of changes in the nucleotide sequence of the PBRM1 tumor suppressor gene in patients with ccRCC. 210 pairs of DNA samples isolated from ccRCC tissue were studied. Analysis of changes in the nucleotide sequence of DNA was carried out by HRM analysis and direct sequencing. In the PBRM1 gene, two somatic mutations were found (c.233G>A (p.D45N) in exon 2, c.1675-1676delTC in exon 15) which were not described previously, and one known polymorphic variant rs17264436 (in exon 23). The frequency of detected mutations was 0.95 % of cases. Analysis of the allelic association for the polymorphic locus rs17264436 showed a statistically significant increase in the risk of developing advanced kidney cancer in carriers of allele rs17264436*A, which can be used in the development of prognostic marker panels. Perhaps the low frequency of mutations in the samples we studied is due to the fact that the inactivation of the PBRM1 gene takes place in other ways, and may also be due to the ethno-specificity of the studied group of patients.

Epigallocatechin-3-gallate inhibited cancer stem cell-like properties by targeting hsa-mir-485-5p/RXRα in lung cancer

Non-small-cell lung cancer (NSCLC) appears to be a significant threat to public health worldwide. MicroRNAs have been identified as significant regulators for the development of NSCLC. Previous reports have suggested that hsa-mir-485-5p is dysregulated in various cancers. RXRα, as a kind of nuclear receptor, is an effective target of cancer treatment. Cancer stem cells (CSCs) are recognized as the main cause for tumor metastasis, recurrence, and chemotherapy resistance. However, the mechanism by which hsa-mir-485-5p and RXRα modulate CSCs in NSCLC remains unknown. Here, we found that hsa-mir-485-5p was decreased in serum samples from patients with NSCLC and NSCLC cells. Meanwhile, epigallocatechin-3-gallate (EGCG), an effective anticancer compound extracted from green tea, can enhance hsa-mir-485-5p expression. Hsa-mir-485-5p mimics markedly inhibited NSCLC cell growth and induced cell apoptosis. However, inhibition of hsa-mir-485-5p significantly enriched CSC-like traits. Moreover, bioinformatics analysis predicted the binding correlation between hsa-mir-485-5p and RXRα, which was confirmed by a dual-luciferase reporter assay. We observed that RXRα was increased in NSCLC and EGCG could inhibit RXRα levels dose dependently. In addition, RXRα upregulation or activation expanded the CSC-like properties of NSCLC cells, whereas RXRα inhibition or inactivation could exert a reverse phenomenon. Consistently, in vivo experiments also validated that EGCG could repress the CSC-like characteristics by modulating the hsa-mir-485-5p/RXRα axis. Our findings may reveal a novel molecular mechanism for the treatment of NSCLC.

Deciphering splenic marginal zone lymphoma pathogenesis: the proposed role of microRNA

Splenic marginal zone lymphoma (SMZL) is a malignancy of mature B-cells that primarily involves the spleen, but can affect peripheral organs as well. Even though SMZL is overall considered an indolent malignancy, the majority of cases will eventually progress to be more aggressive. In recent years, the gene expression profile of SMZL has been characterized in an effort to identify: 1) the etiology of SMZL, 2) biological consequences of SMZL, and 3) putative therapeutic targets. However, due to the vast heterogeneity of the malignancy, no conclusive target(s) have been deciphered. However, the role of miRNA in SMZL, much as it has in chronic lymphocytic leukemia, may serve as a guiding light. As a result, we review the comprehensive expression profiling in SMZL to-date, as well as describe the miRNA (and potential mechanistic roles) that may play a role in SMZL transformation, particularly within the 7q region.

MicroRNA-485-5p reduces O-GlcNAcylation of Bmi-1 and inhibits colorectal cancer proliferation

Emerging evidences showed that miRNAs are involved in the oncogenesis of many cancers. Here, miRNA microarray analysis was performed to screen the significant miRNAs involved in the progression of colorectal cancer (CRC), miR-485-5p was chosen for further study. We found that the expression of miR-485-5p was significantly lower in CRC specimens and cell lines. In addition, low expression level of miR-485-5p is correlated with tumor progression and poor survival in CRC patients. Based on in vitro and in vivo assays, we found that miR-485-5p significantly inhibits CRC proliferation. Moreover, our results showed that miR-485-5p inhibits cell proliferation by reducing Bmi-1 protein expression, which has been reported to control the proliferation of many cancers. Mechanistically, OGT is a direct target of miR-485-5p, and miR-485-5p could inhibit the O-GlcNAcylation level of Bmi-1 by OGT. Overall, these results suggested that as a tumor suppressor, miR-485-5p may regulate CRC cells proliferation, which could regulate the O-GlcNAcylation and the stability of Bmi-1 through targeting OGT. This may give insight into a novel mechanism and therapy of CRC growth.

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 Single Nucleotide Polymorphism in HPGD Gene Is Associated with Prostate Cancer Risk

Introduction: The HPGD gene was associated with some cancers, such as colorectal, breast, prostate, and bladder. However, detailed role of 15-hydroxyprostaglandin dehydrogenase (HPGD) gene remain unclear in prostate cancer. The study was to investigate the correlation between rs8752 that located in the 3'untranslated region (UTR) of the 15-hydroxyprostaglandin dehydrogenase (HPGD) gene and prostate cancer (PCa) risk.

Materials and Methods: 109 patients from the First Affiliate Hospital of Soochow University were recruited. According to the results of pathologic diagnosis, all patients were divided into two groups (prostate cancer and benign prostatic hyperplasia). The single-nucleotide polymorphism (SNP) rs8752 was genotyped in all samples by direct sequencing.

Results: 54 prostate cancer and 55 BPH patients were included with a median age of 70.41 and 67.62 years, respectively. No statistically significant difference between two groups in patient criteria. The frequency of the GG homozygote and AG+GG genotype were 37.74% and 62.26% in 54 prostate cancer samples, while in 55BPH patients, values were 62.50% and 37.50%. Compared with the GG genotype, the combined GA+AA genotypes had a significantly higher risk of prostate cancer (OR = 2.750; 95% CI: 1.266-5.971, p = 0.011). Furthermore, the risk effect was obtained in subgroups of PCa patient group, the AA+AG genotypes significantly associated with the higher Gleason score samples (AA+AG vs GG: OR = 3.50, 95%CI = 1.106-11.072, p = 0.033) and the risk of pathological stage (AA+AG vs GG: OR = 4.00, 95%CI = 1.253-12.767, p = 0.019).

Conclusions: rs8752 in the 3'untranslated region (UTR) of the 15-hydroxyprostaglandin dehydrogenase (HPGD) gene was found to be responsible for the susceptibility to prostate cancer in Chinese individuals.

A tumor-suppressive microRNA, miRNA-485-5p, inhibits glioma cell proliferation and invasion by down-regulating TPD52L2

Glioblastoma multiforme is the most deadly primary brain tumor and has no effective treatment. Therefore, it is important to identify novel and effective therapies that impede glioma tumorigenesis. MicroRNAs (miRNAs) are helpful analytical biomarkers and may be useful targets for treating multiple human cancers. Previous reports suggest that miRNA-485-5p is dysregulated and contributes to tumorigenesis in some cancer types. Nevertheless, the biological role of miRNA-485-5p in glioma is not well understood. In this study, we demonstrated that miRNA-485-5p expression was reduced in gliomat issues and cell lines. In addition, miRNA-485-5p overexpression inhibited cell proliferation, migration, and invasion in glioma cell lines. Additionally, we identified Tumor Protein D52 Like 2 (TPD52L2) as a direct target of miRNA-485-5p. Moreover, we showed that miRNA-485-5p regulated glioma tumorigenesis by down-regulating TPD52L2 expression in vitro and in vivo. Our results suggest that miRNA-485-5p is a suppressor of glioma tumorigenesis and could serve as a novel candidate for therapeutic applications in glioma treatment.

MicroRNAs and Their Impact on Breast Cancer, the Tumor Microenvironment, and Disparities

Breast cancer is a worldwide health issue as it represents the leading cause of cancer in women and the second-leading cause of cancer-related mortality in women, with an increasing incidence. Nothing speaks more clearly to the shocking breast cancer health disparities than the fact that African American (AA) women are as likely to get breast cancer as Caucasian American (CA) women, yet have a higher breast cancer death rate. It is becoming increasingly apparent that racial disparity in cancer exists due to molecular differences in tumor biology as well as, or in addition to, socioeconomic and standard of care issues (Albain, Unger, Crowley, Coltman, & Hershman, 2009). A greater understanding of the risk factors and biological links associated with breast cancer, will significantly impact AA communities due to the higher deaths associated with this disease in this population. microRNAs are small noncoding RNA molecules that were recently discovered as major players in the regulation of many diseases including cancer. Although, there are many studies that have investigated the role of miRNAs in breast cancer, few have investigated their role if any in breast cancer disparities. This review serves to summarize the current published literature that is involved in the study of microRNAs and their impact on breast cancer disparities.

MiR-485-3p and miR-485-5p suppress breast cancer cell metastasis by inhibiting PGC-1α expression

Breast cancer is the worldwide leading cause of cancer mortality in women. The majority of deaths from breast cancer arise from metastasis of local tumors. Cancer cells support their rapid proliferation by diverting metabolites into anabolic pathways, but during cancer metastasis, the proliferative program of invasive cancer cells is suspended for a migratory phenotype. In this study, we demonstrated that both mature forms of miRNA-485, miR-485-3p and miR-485-5p were involved in regulating mitochondrial respiration, cell migration and cell invasion in breast cancer cells by directly targeting and inhibiting the expression of PGC-1α. Specifically, the expression levels of both miR-485-3p and miR-485-5p were decreased in breast cancer tissues. Overexpression of miR-485-3p and miR-485-5p suppressed mitochondrial respiration and potential for cell migration and invasion in vitro, and also inhibited spontaneous metastasis of breast cancer cells in vivo. The suppression of mitochondrial respiration and cell invasion could be partially relieved by restoration of PGC-1α expression.

UCA1 functions as a competing endogenous RNA to suppress epithelial ovarian cancer metastasis

Urothelial cancer associated 1 (UCA1) is an example of functional long noncoding RNAs involved in many biologic processes. However, little is known about the association between UCA1 expression and metastasis in epithelial ovarian cancer (EOC). Findings of this study confirmed that not only UCA1 was aberrantly upregulated in EOC tissues and cells, but also correlated with status of lymph node metastasis and FIGO stage. Furthermore, univariate and multivariate analyses showed that UCA1 was a prognostic factor for overall survival in EOC patients. In vitro, knockdown of UCA1 reduced the invasion and migration ability of EOC cells. The results showed that UCA1 could function as an endogenous sponge by directly binding to miR-485-5p. Depletion of UCA1 was involved in the downregulation of matrix metallopeptidase 14 (MMP14) expression, a target gene of miR-485-5p. In conclusion, our work indicates that UCA1 is a new prognostic biomarker for EOC, establishing a novel connection among UCA1, miR-485-5p, and MMP14 in EOC metastasis.

MicroRNA expression profiles differentiate chronic pain condition subtypes

Chronic pain is a significant health care problem, ineffectively treated because of its unclear etiology and heterogeneous clinical presentation. Emerging evidence demonstrates that microRNAs (miRNAs) regulate the expression of pain-relevant genes, yet little is known about their role in chronic pain. Here, we evaluate the relationship among pain, psychological characteristics, plasma cytokines, and whole blood miRNAs in 22 healthy controls (HCs); 33 subjects with chronic pelvic pain (vestibulodynia, VBD); and 23 subjects with VBD and irritable bowel syndrome (VBD + IBS). VBD subjects were similar to HCs in self-reported pain, psychological profiles, and remote bodily pain. VBD + IBS subjects reported decreased health and function; and an increase in headaches, somatization, and remote bodily pain. Furthermore, VBD subjects exhibited a balance in proinflammatory and anti-inflammatory cytokines, whereas VBD + IBS subjects failed to exhibit a compensatory increase in anti-inflammatory cytokines. VBD subjects differed from controls in expression of 10 miRNAs of predicted importance for pain and estrogen signaling. VBD + IBS subjects differed from controls in expression of 11 miRNAs of predicted importance for pain, cell physiology, and insulin signaling. miRNA expression was correlated with pain-relevant phenotypes and cytokine levels. These results suggest that miRNAs represent a valuable tool for differentiating VBD subtypes (localized pain with apparent peripheral neurosensory disruption vs widespread pain with a central sensory contribution) that may require different treatment approaches.

miR-485-5p acts as a negative regulator in gastric cancer progression by targeting flotillin-1

MicroRNAs (miRNAs) play important roles in cancer progression including gastric cancer. miR-485-5p is reported as a potential suppressor in breast cancer, but its expression, cellular function and clinic features in gastric cancer is not known. In our study, we found that miR-485-5p expression was down-regulated in gastric cancer cell lines. miR-485-5p could inhibit gastric cancer cell growth in vitro and in vivo. We also found that miR-485-5p suppressed gastric cancer cell metastasis and sphere formation. It was confirmed flotillin-1 (Flot1) as a direct target of miR-485-5p, and up-regulation of miR-485-5p could decrease expression of Flot1 in gastric cancer cells. Further investigation showed that ectopic expression of Flot1 partially reversed the inhibition effect of enforced miR-485-5p expression on the malignant phenotypes of gastric cancer cells. The low expression of miR-485-5p in gastric cancer tissues was related to advanced clinical features and poorer prognosis. Our study suggested that miR-485-5p could be a potential prognostic marker and functions as a tumor suppressor in human gastric cancer by post-transcriptionally targeting Flot1.

MicroRNA-485-5p suppresses cell proliferation and invasion in hepatocellular carcinoma by targeting stanniocalcin 2

Increasing evidences indicate that dys-regulation of MicroRNAs contributes to hepatocellular carcinoma. However, the roles of miR-485-5p in HCC are still largely unexplored. In the present study, our quantitative real-time PCR analysis found that miR-485-5p was significantly down-regulated in 50 pairs of human HCC tissues. Moreover, the reduced expression of miR-485-5p was significantly correlated with larger tumor size and more tumor number in patients with HCC. In vitro studies further showed that overexpression of miR-485-5p mimics could inhibit, while its antisense oligos promote cell proliferation and invasion. Results from the dual-luciferase reporter gene assays and western blot further showed that stanniocalcin 2 was a direct target of miR-485-5p. Therefore, our data suggest a novel role for miR-485-5p in the regulation of HCC progression.

ceRNA in cancer: possible functions and clinical implications

Competing endogenous RNAs (ceRNAs) are transcripts that can regulate each other at post-transcription level by competing for shared miRNAs. CeRNA networks link the function of protein-coding mRNAs with that of non-coding RNAs such as microRNA, long non-coding RNA, pseudogenic RNA and circular RNA. Given that any transcripts harbouring miRNA response element can theoretically function as ceRNAs, they may represent a widespread form of post-transcriptional regulation of gene expression in both physiology and pathology. CeRNA activity is influenced by multiple factors such as the abundance and subcellular localisation of ceRNA components, binding affinity of miRNAs to their sponges, RNA editing, RNA secondary structures and RNA-binding proteins. Aberrations in these factors may deregulate ceRNA networks and thus lead to human diseases including cancer. In this review, we introduce the mechanisms and molecular bases of ceRNA networks, discuss their roles in the pathogenesis of cancer as well as methods of predicting and validating ceRNA interplay. At last, we discuss the limitations of current ceRNA theory, propose possible directions and envision the possibilities of ceRNAs as diagnostic biomarkers or therapeutic targets.

Evaluation of miRNA-binding-site SNPs of MRE11A, NBS1, RAD51 and RAD52 involved in HRR pathway genes and risk of breast cancer in China

MiRNA-binding-site single nucleotide polymorphisms (SNPs) in homologous recombination repair (HRR) pathway genes may change DNA repair capacity and affect susceptibility to cancer though complex gene-gene and gene-reproductive factors interactions. However, these SNPs associated with breast cancer (BC) are still unclear in Chinese women. Therefore, we conducted a case-control study to evaluate the genetic susceptibility of the five miRNA-binding-site SNPs in HRR pathway genes (MRE11A rs2155209, NBS1 rs2735383, RAD51 rs963917 and rs963918 and RAD52 rs7963551) in the development of BC. MRE11A rs2155209 and RAD52 rs7963551 were found to be associated with BC risk (ORadjusted: 1.87; 95 % CI: 1.23-2.86 and ORadjusted: 0.36; 95 % CI: 0.24-0.58). NBS1 rs2735383, RAD51 rs963917 and rs963918 were associated with BC risk after stratification according to reproductive factors. Haplotypes of Crs963917Ars963918 decreased the risk of BC (ORadjusted: 0.53; 95 % CI: 0.4-0.68), while the Trs963917Ars963918 and Trs963917Grs963918 haplotypes could increase the risk of BC (ORadjusted: 1.28; 95 % CI: 1.05-1.57 and ORadjusted: 1.31; 95 % CI: 1.09-1.62). Combined effect of risk alleles showed that the five SNPs were associated with increased BC risk in a dose-dependent manner (P trend = 0.003). The GC genotype of rs2735383, AG + GG genotype of rs963918 and AC + CC genotype of rs7963551 were associated with PR positivity of BC patients. These findings suggest that the miRNA-binding-site SNPs involved in HRR pathway genes may affect susceptibility of BC in Chinese women; moreover, the interactions of gene-gene and gene-reproductive factors play vital roles in the progression of BC. Further functional studies with larger sample are needed to support and validate these findings.

Critical analysis of the potential for microRNA biomarkers in breast cancer management

Breast cancer is a complex and heterogeneous disease. Signaling by estrogen receptor (ER), progesterone receptor (PR), and/or human EGF-like receptor 2 (HER2) is a main driver in the development and progression of a large majority of breast tumors. Molecular characterization of primary tumors has identified major subtypes that correlate with ER/PR/HER2 status, and also subgroup divisions that indicate other molecular and cellular features of the tumors. While some of these research findings have been incorporated into clinical practice, several challenges remain to improve breast cancer management and patient survival, for which the integration of novel biomarkers into current practice should be beneficial. microRNAs (miRNAs) are a class of short non-coding regulatory RNAs with an etiological contribution to breast carcinogenesis. miRNA-based diagnostic and therapeutic applications are rapidly emerging as novel potential approaches to manage and treat breast cancer. Rapid technological development enables specific and sensitive detection of individual miRNAs or the entire miRNome in tissues, blood, and other biological specimens from breast cancer patients. This review focuses on recent miRNA research and its potential to address unmet clinical needs and challenges. The four sections presented discuss miRNA findings in the context of the following clinical challenges: biomarkers for early detection; prognostic and predictive biomarkers for treatment decisions using targeted therapies against ER and HER2; diagnostic and prognostic biomarkers for subgrouping of triple-negative breast cancer, for which there are currently no targeted therapies; and biomarkers for monitoring and characterization of metastatic breast cancer. The review concludes with a critical analysis of the current state of miRNA breast cancer research and the need for further studies using large patient cohorts under well-controlled conditions before considering the clinical implementation of miRNA biomarkers.

Genomic alterations as mediators of miRNA dysregulation in ovarian cancer

Ovarian cancer is the fifth most common cause of cancer death in women worldwide. Serous epithelial ovarian cancer (SEOC) is the most common and aggressive histological subtype. Widespread genomic alterations go hand-in-hand with aberrant DNA damage signaling and are a hallmark of high-grade SEOC. MicroRNAs (miRNAs) are a class of small noncoding RNA molecules that are nonrandomly distributed in the genome. They are frequently located in chromosomal regions susceptible to copy number variation (CNV) associated with malignancy that can influence their expression. Widespread changes in miRNA expression have been reported in multiple cancer types including ovarian cancer. This review examines CNV and single nucleotide polymorphisms, two common types of genomic alterations that occur in ovarian cancer, in the context of their influence on the expression of miRNA and the ability of miRNA to bind to and regulate their target genes. This includes genes encoding proteins involved in DNA repair and the maintenance of genomic stability. Improved understanding of mechanisms of miRNA dysregulation and the role of miRNA in ovarian cancer will provide further insight into the pathogenesis and treatment of this disease.