MicroRNA expression and its implications for the diagnosis and therapeutic strategies of breast cancer

SERS biosensors based on catalytic hairpin self-assembly and hybridization chain reaction cascade signal amplification strategies for ultrasensitive microRNA-21 detection

A highly sensitive surface-enhanced Raman scattering (SERS) biosensor has been developed for the detection of microRNA-21 (miR-21) using an isothermal enzyme-free cascade amplification method involving catalytic hairpin assembly (CHA) and hybridization chain reaction (HCR). The CHA reaction is triggered by the target miR-21, which causes hairpin DNA (C1 and C2) to self-assemble into CHA products. After AgNPs@Capture captures the resulting CHA product, the HCR reaction is started, forming long-stranded DNA on the surface of AgNPs. A strong SERS signal is generated due to the presence of a large amount of the Raman reporter methylene blue (MB) in the vicinity of the SERS "hot spot" on the surface of AgNPs. The monitoring of the SERS signal changes of MB allows for the highly sensitive and specific detection of miR-21. In optimal conditions, the biosensor exhibits a satisfactory linear range and a low detection limit for miR-21 of 42.3 fM. Additionally, this SERS biosensor shows outstanding selectivity and reproducibility. The application of this methodology to clinical blood samples allows for the differentiation of cancer patients from healthy controls. As a result, the CHA-HCR amplification strategy used in this SERS biosensor could be a useful tool for miRNA detection and early cancer screening.

The integration of multidisciplinary approaches revealed PTGES3 as a novel drug target for breast cancer treatment

BACKGROUND

The main challenge in personalized treatment of breast cancer (BC) is how to integrate massive amounts of computing resources and data. This study aimed to identify a novel molecular target that might be effective for BC prognosis and for targeted therapy by using network-based multidisciplinary approaches.

METHODS

Differentially expressed genes (DEGs) were first identified based on ESTIMATE analysis. A risk model in the TCGA-BRCA cohort was constructed using the risk score of six DEGs and validated in external and clinical in-house cohorts. Subsequently, independent prognostic factors in the internal and external cohorts were evaluated. Cell viability CCK-8 and wound healing assays were performed after PTGES3 siRNA was transiently transfected into the BC cell lines. Drug prediction and molecular docking between PTGES3 and drugs were further analyzed. Cell viability and PTGES3 expression in two BC cell lines after drug treatment were also investigated.

RESULTS

A novel six-gene signature (including APOOL, BNIP3, F2RL2, HINT3, PTGES3 and RTN3) was used to establish a prognostic risk stratification model. The risk score was an independent prognostic factor that was more accurate than clinicopathological risk factors alone in predicting overall survival (OS) in BC patients. A high risk score favored tumor stage/grade but not OS. PTGES3 had the highest hazard ratio among the six genes in the signature, and its mRNA and protein levels significantly increased in BC cell lines. PTGES3 knockdown significantly inhibited BC cell proliferation and migration. Three drugs (gedunin, genistein and diethylstilbestrol) were confirmed to target PTGES3, and genistein and diethylstilbestrol demonstrated stronger binding affinities than did gedunin. Genistein and diethylstilbestrol significantly inhibited BC cell proliferation and reduced the protein and mRNA levels of PTGES3.

CONCLUSIONS

PTGES3 was found to be a novel drug target in a robust six-gene prognostic signature that may serve as a potential therapeutic strategy for BC.

ER Negative Breast Cancer and miRNA: There Is More to Decipher Than What the Pathologist Can See!

Breast cancer (BC), the most prevalent cancer in women, is a heterogenous disease. Despite advancements in BC diagnosis, prognosis, and therapeutics, survival rates have drastically decreased in the metastatic setting. Therefore, BC still remains a medical challenge. The evolution of high-throughput technology has highlighted gaps in the classification system of BCs. Of particular interest is the notorious triple negative BC, which was recounted as being heterogenous itself and it overlaps with distinct subtypes, namely molecular apocrine (MA) and luminal androgen (LAR) BCs. These subtypes are, even today, still misdiagnosed and poorly treated. As such, researchers and clinicians have been looking for ways through which to refine BC classification in order to properly understand the initiation, development, progression, and the responses to the treatment of BCs. One tool is biomarkers and, specifically, microRNA (miRNA), which are highly reported as associated with BC carcinogenesis. In this review, the diverse roles of miRNA in estrogen receptor negative (ER-) and androgen receptor positive (AR+) BC are depicted. While highlighting their oncogenic and tumor suppressor functions in tumor progression, we will discuss their diagnostic, prognostic, and predictive biomarker potentials, as well as their drug sensitivity/resistance activity. The association of several miRNAs in the KEGG-reported pathways that are related to ER-BC carcinogenesis is presented. The identification and verification of accurate miRNA panels is a cornerstone for tackling BC classification setbacks, as is also the deciphering of the carcinogenesis regulators of ER - AR + BC.

Gene expression of angiogenesis and apoptotic factors in female BALB/c mice with breast cancer after eight weeks of aerobic training

OBJECTIVES

Breast cancer is the most common cancer in women, caused by a disorder in the angiogenesis and apoptosis process. Exercise can affect the process of angiogenesis and apoptosis in the tumor tissue. Thus, the aim of the present study was to investigate the changes in angiogenesis and apoptotic factors in mice with breast cancer after 8 weeks of exercise training.

MATERIALS AND METHODS

Sixteen females BALB/c mice (age: 3-5 weeks and weight: 17.1 ± 0.1 g) with breast cancer were randomly divided into two groups of aerobic training and control. The aerobic training included 8 weeks and 5 sessions per week of running with an intensity of 14-20 m.min-1. HIF-1α, VEGF, miR-21 and cytochrome C, Apaf-1, caspase-9, and caspase-3 gene expressions were examined by real-time PCR. Repeated measures ANOVA, Bonferroni's post hoc test, and independent samples t-test were used to analyze the data (P<0.05).

RESULTS

The results showed that aerobic training reduced the growth of tumor volume and significantly reduced miR-21 gene expression. Aerobic training also significantly increased the gene expression of HIF-1α, cytochrome C, Apaf-1, caspase-9, and caspase-3, while changes in VEGF gene expression were not statistically significant.

CONCLUSION

It appears that aerobic exercise training reduces tumor size and ameliorates breast cancer by reducing miR-21 gene expression, suppressing the apoptosis process, and reducing angiogenesis.

Changes in plasma HDL and its subcomponents HDL2b and HDL3 regulate inflammatory response by modulating SOCS1 signaling to affect severity degree and prognosis of sepsis

OBJECTIVES

To explore if SOCS1 is regulated by plasma HDL and its subcomponents HDL2b and HDL3 to affect inflammatory reaction then to influence the severity degree and prognosis of sepsis.

METHODS

One hundred sepsis patients in ICU and 85 normal control persons from October 2018 to October 2019 in our hospital were enrolled. Adult male C57BL/6 mice were used to establish sepsis model by CLP method. HDL, CRP, and WBC count of human were measured using an auto-analyzer. Plasma HDL, IL-1β, and TNF-α proteins levels of mice were measured with ELISA. Microfluidic chip was used for plasma HDL2b and HDL3 detections. SOCS1 in liver and spleen of mice were measured by qRT-PCR. The relationship between plasma HDL//HDL2b and inflammatory indices/SOCS1 in liver/spleen was analyzed with spearman correlation coefficient method. The sepsis patients/mice were divided into non-survival and survival groups. The sepsis patients were divided into severe and mild sepsis patients based on the SOFA score or divided into high and low score groups according to the APACHE II score. The sepsis mice were divided into high and low score group based on the modified sepsis severity score criterion.

RESULTS

Plasma HDL and HDL2b levels were significantly declined (P < 0.01), while HDL3 was normal in both sepsis patients and mice (P > 0.05). Plasma HDL and HDL2b were negatively associated with the serum CRP concentration and positively correlated with the prognosis and severity in sepsis patients (P < 0.05). Moreover, the downregulated plasma HDL but not HDL2b was negatively related to increased SOCS1 mRNA levels in liver and spleen of mice, which were positively connected with TNF-α and IL-1β protein levels (P < 0.05).

CONCLUSIONS

Plasma HDL is downregulated in sepsis, which may facilitate inflammatory reaction then activate the SOCS1 signaling to regulate the severity and affect prognosis of sepsis. The decline of plasma HDL2b content could aggravate the severity and poor prognosis of sepsis through facilitating inflammatory reaction. The plasma HDL3 is not involved in sepsis. The more and further explorations may be needed.

Identification of a 6-gene signature for the survival prediction of breast cancer patients based on integrated multi-omics data analysis

Purpose

To identify a gene signature for the prognosis of breast cancer using high-throughput analysis.

Methods

RNASeq, single nucleotide polymorphism (SNP), copy number variation (CNV) data and clinical follow-up information were downloaded from The Cancer Genome Atlas (TCGA), and randomly divided into training set or verification set. Genes related to breast cancer prognosis and differentially expressed genes (DEGs) with CNV or SNP were screened from training set, then integrated together for feature selection of identify robust biomarkers using RandomForest. Finally, a gene-related prognostic model was established and its performance was verified in TCGA test set, Gene Expression Omnibus (GEO) validation set and breast cancer subtypes.

Results

A total of 2287 prognosis-related genes, 131 genes with amplified copy numbers, 724 gens with copy number deletions, and 280 genes with significant mutations screened from Genomic Variants were closely correlated with the development of breast cancer. A total of 120 candidate genes were obtained by integrating genes from Genomic Variants and those related to prognosis, then 6 characteristic genes (CD24, PRRG1, IQSEC3, MRGPRX, RCC2, and CASP8) were top-ranked by RandomForest for feature selection, noticeably, several of these have been previously reported to be associated with the progression of breast cancer. Cox regression analysis was performed to establish a 6-gene signature, which can stratify the risk of samples from training set, test set and external validation set, moreover, the five-year survival AUC of the model in the training set and validation set was both higher than 0.65. Thus, the 6-gene signature developed in the current study could serve as an independent prognostic factor for breast cancer patients.

Conclusion

This study constructed a 6-gene signature as a novel prognostic marker for predicting the survival of breast cancer patients, providing new diagnostic/prognostic biomarkers and therapeutic targets for breast cancer patients.

RETRACTED: LncRNA GAS6-AS1 facilitates the progression of breast cancer by targeting the miR-324-3p/SETD1A axis to activate the PI3K/AKT pathway

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the current Editor in Chief, with the agreement of all authors. The article is being retracted due to inappropriate manipulation of the original data for presentation in Figures 2C, 5C and 6C. Upon further investigation and discussion with the authors, insufficient evidence was provided to support a reasonable explanation for these mistakes. In addition, the authors could not provide convincing original data supporting other figures of the manuscript, e.g. Figures 2G, 4 and 6A. Based on these findings, the Editor in Chief and the authors have decided to retract the study. The authors apologize for any inconvenience caused.

MicroRNA-1297 downregulation inhibits breast cancer cell epithelial-mesenchymal transition and proliferation in a FA2H-dependent manner

Breast cancer (BC) is one of the most common malignant tumors among women worldwide. MicroRNAs (miRs) may be involved in several types of human cancer, including gastric, liver, lung and breast cancer. The aim of the present study was to investigate the effect of miR-1297 on MDA-MB-231 cell epithelial-mesenchymal transition (EMT) and proliferation, and the underlying molecular mechanisms. MDA-MB-231 cells were transfected with miR-1297 inhibitor or inhibitor control for 48 h. Subsequently, MTT and flow cytometry assays indicated that miR-1297 inhibitor significantly decreased cell proliferation and induced apoptosis compared with the inhibitor control group. In addition, reverse transcription-quantitative PCR and western blotting suggested that miR-1297 inhibitor suppressed EMT in MDA-MB-231 cells compared with the inhibitor control group. TargetScan bioinformatics analysis and a dual-luciferase reporter gene assay were performed, which predicted that miR-1297 directly targeted fatty acid 2-hydroxylase (FA2H). Furthermore, MDA-MB-231 cells were transfected with control-plasmid or FA2H-plasmid for 48 h. The results demonstrated that FA2H overexpression decreased MDA-MB-231 cell proliferation and increased apoptosis compared with the control-plasmid group. Additionally, FA2H-plasmid increased E-cadherin expression levels, and reduced N-cadherin and matrix metalloproteinase 9 expression levels at both the protein and mRNA level compared with control-plasmid. Finally, MDA-MB-231 cells were transfected with control-small interfering (si)RNA, FA2H-siRNA, inhibitor control, miR-1297 inhibitor, miR-1297 inhibitor + control siRNA or miR-1297 inhibitor + FA2H-siRNA, and the results suggested that the biological effects of miR-1297 inhibitor were reversed by co-transfection with FA2H siRNA. In conclusion, the present study indicated that miR-1297/FA2H might serve as a novel potential biomarker and therapeutic target for BC.

The interaction between MALAT1 target, miR-143-3p, and RALGAPA2 is affected by functional SNP rs3827693 in breast cancer

A higher expression of MALAT1 has been reported in breast cancer. However, more studies are needed to decipher the mechanisms by which this lncRNA imposes its oncogenic effects. In this study, blood and tissue samples were taken from healthy normal and breast cancer subjects. qPCR was used to analyze the gene expression. HRM-PCR method was carried out to genotype the selected samples. Computational analysis was recruited to find novel targets of MALAT1 and miR-143-3p. The data analyses revealed that MALAT1 was up-regulated in breast cancer and could be a distinctive factor to diagnose cancer. The expression of MALAT1 was inversely correlated with miR-143-3p expression in the studied clinical samples. The down-regulation of miR-143-3p was proven in the clinical tumor samples as compared to the healthy controls. A negative correlation of miR-143-3p with its putative target, RALGAPA2 was observed. A functional SNP rs3827693 located within the 3'UTR region of RALGAPA2 mRNA was validated in this study to associate with breast cancer risk. The rs3827693 allele G significantly decreased the breast cancer incidence and augmented the negative correlation between RALGAPA2 and miR-143-3p, presumably through strengthening the interaction between these two transcripts. This study proposed MALAT1 miR-143-3p and miR-143-3p RALGAPA2 axis in breast cancer, whereby the latter can be altered by the clinically functional SNP rs3827693.

Differential expression of miR-1297, miR-3191-5p, miR-4435, and miR-4465 in malignant and benign breast tumors

OBJECTIVES

MicroRNAs (miRs) are a class of small non-coding RNAs which are associated with tumor growth and progression. In the present study, we assessed the expression of selected miRs in malignant, benign, and adjacent normal breast tissues.

MATERIALS AND METHODS

The expression of miR-1297, miR-3191-5P, miR-4435, and miR-4465 were evaluated in malignant (n=50), benign (n=35), and adjacent normal breast tissues (n=20) using qRT-PCR. Receiver operating characteristic (ROC) curves and the area under the ROC curve (AUC) were generated for evaluating the diagnostic values of miRs. To evaluate diagnostic efficacy, miRs-based score was obtained using the logistic regression model.

RESULTS

Among malignant tumors, the expression of miR-1297, miR-3191-5p, and miR-4435 was significantly lower (P=0.024, P<0.001 and P=0.031), respectively. The expression of miR-4465 was higher (P=0.023) than that of normal tissue. The expression of these miRs was lower than those of benign tumors (P<0.01, P<0.001, P<0.0001, and P<0.01, respectively). We observed a positive correlation between miR-4465 expression levels and tumor stage (P=0.042) and a negative correlation with grade and Ki-67 score (P<0.05). The AUCs for miR-1297, miR-3191-5p, miR-4435, and miR-4465 in malignant tumors versus normal tissues were 0.784, 0.700, 0.976, and 0.865 and versus benign tumors they were 0.938, 0.857, 0.981, and 0.785, respectively. The optimal logit(P) value of 0.262 distinguished malignant from normal subjects with a sensitivity of 0.91, specificity of 0.85, and an overall accuracy of 0.89.

CONCLUSION

The panel of these miRs are suggested as possible onco-miRs(miR-4465) or tumor suppressor-miRs (miR-3191-5P, miR-1297, miR-4435). Overall, our results indicated that these miRs could be introduced as diagnostic biomarkers in breast cancer patients.

miR‑28‑5p inhibits the migration of breast cancer by regulating WSB2

MicroRNAs (miRNAs or miRs) play an important role in the tumorigenesis and progression of breast cancer. However, the function of miR‑28‑5p in breast cancer migration has yet to be determined. In the present study, Human MicroRNA Expression Database (HMED) analysis revealed that the expression level of miR‑28‑5p was significantly lower in breast cancer tissue than in normal breast tissue. Kaplan-‑Meier plotter (KMPLOT) analysis revealed that the low expression level of miR‑28‑5p was associated with a poor survival in breast cancer. In addition, reverse transcription‑quantitative PCR (RT‑qPCR) revealed that the expression of miR‑28‑5p was significantly lower in breast cancer cell lines compared with that in human mammary epithelial cells (HMECs). Moreover, transfection with miR‑28‑5p mimics suppressed the migration of MCF‑7 cells, whereas an miR‑28‑5p inhibitor exerted the opposite effect. Gene chip assay identified 648 differentially expressed genes (DEGs) in cells overexpressing miR‑28‑5p. The DEGs are enriched in the 'focal adhesion' and 'pathway in cancer' pathways. The expression levels of Ras‑related protein Rap‑1b (RAP1B), WD repeat and SOCS box containing 2 (WSB2) and vascular endothelial growth factor A (VEGFA) were confirmed by RT‑qPCR. Furthermore, transfection with miR‑28‑5p mimics decreased WSB2 expression, whereas the miR‑28‑5p inhibitor increased the expression of WSB2, at both the transcriptional and translational levels. miR‑28‑5p targets the 3'UTR of WSB2, and the binding site is conserved in multiple species, with a consensus motif of 5'‑AGCUCCUU‑3'. Moreover, WSB2 overexpression promoted the migration of MCF‑7 cells which had been inhibited by miR‑28‑5p. UALCAN analysis revealed that WSB2 was significantly upregulated in primary breast tumor tissue, and a high expression level of WSB2 was associated with a poor survival in breast cancer. Furthermore, immunohistochemistry revealed that the expression of WSB2 was markedly higher in breast cancer tissue compared with that in adjacent normal breast tissue. Taken together, the findings of the present study demonstrate that miR‑28‑5p inhibits the migration of breast cancer cells by regulating WSB2 expression, and the miR‑28‑5p/WSB2 axis may be a novel therapeutic target in breast cancer.

Kinesin family member 11 is a potential therapeutic target and is suppressed by microRNA-30a in breast cancer

Kinesin family member 11 (KIF11) is a plus end‐directed kinesin indispensable for the formation of the bipolar spindle in metaphase, where it objects to the action of minus end‐directed molecular motors. Here, we hypothesize that KIF11 might be a therapeutic target of breast cancer and regulated by miR‐30a. Cell Counting Kit 8 assays were used to investigate cell proliferation. Invasion assays were used to survey the motility of cells. Kaplan‐Meier and Cox proportional analyses were employed for this outcome study. The prognostic significance and performance of KIF11 were validated on 17 worldwide independent microarray datasets and two The Cancer Genome Atlas‐Breast Invasive Carcinoma sets. microRNA was predicted targeting KIF11 through sequence alignment in microRNA.org and confirmed by coexpression analysis in human breast cancer samples. Dual‐luciferase reporter assays were employed to validate the interaction between miR‐30a and KIF11 further. Higher KIF11 mRNA levels and lower miR‐30a were significantly associated with poor survival of breast cancer patients. Inhibition of KIF11 by small‐hairpin RNA significantly reduced the proliferation and invasion capabilities of the breast cancer cells. Meanwhile, downregulation of KIF11 could enhance the cytotoxicity of adriamycin in breast cancer cell lines MCF‐7 and MDA‐MB‐231. A population study also validated that chemotherapy and radiotherapy significantly improved survival in early‐stage breast cancer patients with low KIF11 expression levels. Further bioinformatics analysis demonstrated that miR‐30a could interact with KIF11 and validated by dual‐luciferase reporter assays. Therefore, KIF11 is a potential therapeutic target of breast cancer. miR‐30a could specifically interact with KIF11 and suppress its expression in breast cancer.

Downregulation of miR-505 promotes cell proliferation, migration and invasion, and predicts poor prognosis in breast cancer

microRNAs are involved in the tumor progression of various cancer types. The present study aimed to determine the prognostic significance of microRNA-505 (miR-505) in patients with breast cancer and investigate the functional role of miR-505 in BCa progression. The expression of miR-505 was estimated using reverse transcription-quantitative polymerase chain reaction. Kaplan-Meier survival curves and Cox regression analysis were used to evaluate the prognostic value of miR-505 in patients with BCa. Cell experiments were performed to assess the biological function of miR-505 during BCa progression. A significant downregulated expression level of miR-505 was observed in BCa tissues and cells compared with the corresponding controls (P<0.001). The expression of miR-505 was significantly associated with distant metastasis status (P=0.013) and Tumor-Node-Metastasis staging (P=0.002). Furthermore, the overall survival time was significantly shorter for patients with low miR-505 expression compared with those with high miR-505 expression (P<0.001). In addition, miR-505 was identified as an independent prognostic factor for BCa. The results of cell experiments revealed that an overexpression of miR-505 could significantly inhibit BCa cell proliferation, migration and invasion, whereas a downregulation of miR-505 significantly enhanced BCa cell proliferation, migration and invasion (P<0.05). In summary, all data indicated that a low miR-505 expression level is associated with a poor prognosis for patients with BCa and promotes tumor cell proliferation, migration and invasion. Therefore, the aberrant expression of miR-505 may serve as a therapeutic target for BCa.

Dysregulation of EZH2/miR-138 axis contributes to drug resistance in multiple myeloma by downregulating RBPMS

EZH2 is highly expressed in multiple myeloma (MM). However, the molecular mechanisms underlying EZH2 overexpression and its role in drug resistance of MM remain undefined. Here we show that EZH2 is upregulated in drug-resistant MM cells and its aberrant overexpression is associated with poor prognosis of MM patients. Overexpression of EZH2 in parental MM cells renders them resistant to anti-myeloma drugs and suppression of EZH2 displays the opposite effects. Using miRNA target scan algorithms, we identify miR-138 as a regulator of EZH2, which is conversely repressed by EZH2-induced H3K27 trimethylation in MM-resistant cell lines and primary tumor cells. Analysis of ChIP-seq dataset and H3K27me3 ChIP reveals that RBPMS is a direct and functionally relevant target of EZH2. RBPMS silencing confers resistance to MM cells and restoration of RBPMS by miR-138 overexpression re-sensitizes the resistant cells to drug. Importantly, in vivo delivery of miR-138 mimics or pharmacological inhibitor of EZH2 in combination with a proteasome inhibitor, bortezomib, induces significant regression of tumors in xenograft model. This study establishes EZH2/miR-138 axis as a potential therapeutic target for MM.

A 4-microRNA signature predicts lymph node metastasis and prognosis in breast cancer

Recent findings have reported that human microRNAs (miRNAs) could serve as prognostic biomarkers in various cancers. We aimed to identify miRNAs that were associated with lymph node metastasis (LNM) and prognosis in breast cancer patients. A miRNA microarray covering 2019 mature miRNAs was used to identify differentially expressed miRNAs in 9 patients with LNM and 3 patients without LNM. Thirty-five differentially expressed miRNAs were identified, of which 10 significantly were up-regulated, whereas the other 25 were down-regulated in tissues with LNM compared with those without LNM. Seven miRNAs were subjected to quantitative real-time polymerase chain PCR (qRT-PCR) reaction, and 4 miRNAs (miR-191-5p, miR-214-3p, miR-451a, and miR-489) were validated in a total of 159 patients including a training set (n = 64) and a validation set (n = 95). The 4 miRNAs were used to construct a miRNA signature by logistic regression. Risk scores derived from the 4-miRNA signature were calculated to stratify the patients into high- or low-risk groups. Patients with high-risk scores had poorer overall survival and disease-free survival than did those with low-risk scores. The miRNA signature was an independent prognostic factor. MiR-191-5p increased, whereas miR-214-3p, miR-451a, and miR-489 inhibited cell proliferation, migration, and invasion abilities. The 4-miRNA signature may be a reliable prognostic and predictive tool for metastasis and survival in breast cancer patients.

Differential microRNA expression in breast cancer with different onset age

Purpose

The lower breast cancer incidence in Asian populations compared with Western populations has been speculated to be caused by environmental and genetic variation. Early-onset breast cancer occupies a considerable proportion of breast cancers in Asian populations, but the reason for this is unclear. We aimed to examine miRNA expression profiles in different age-onset groups and pathological subtypes in Asian breast cancer.

Methods

At the first stage, 10 samples (tumor: n = 6, normal tissue: n = 4) were analyzed with an Agilent microRNA 470 probe microarray. Candidate miRNAs with expression levels that were significantly altered in breast cancer samples or selected from a literature review were further validated by quantitative real-time PCR (qPCR) of 145 breast cancer samples at the second stage of the process. Correlations between clinicopathological parameters of breast cancer patients from different age groups and candidate miRNA expression were elucidated.

Results

In the present study, the tumor subtypes were significantly different in each age group, and an onset age below 40 had poor disease-free and overall survival rates. For all breast cancer patients, miR-335 and miR-145 were down-regulated, and miR-21, miR-200a, miR-200c, and miR-141 were up-regulated. In very young patients (age < 35 y/o), the expression of 3 and 8 specific miRNAs were up- and down-regulated, respectively. In young patients (36–40 y/o), 3 and 3 specific miRNAs were up- and down-regulated, respectively. miR-532-5p was up-regulated in triple-negative breast cancer.

Conclusions

Differential miRNA expressions between normal and tumor tissues were observed in different age groups and tumor subtypes. Evolutionarily conserved miRNA clusters, which initiate malignancy transformation, were up-regulated in the breast cancers of very young patients. None of the significantly altered miRNAs were observed in postmenopausal patients.

MicroRNA-588 is downregulated and may have prognostic and functional roles in human breast cancer

Background

We explored the expression pattern, prognostic potential, and functional role of microRNA-588 (miR-588) in human breast cancer (BC).

Material/Methods

The expression pattern of miR-588 was assessed by qPCR in BC cell lines and human BC carcinomas. The correlations between miR-588 and BC patients’ clinicopathological characteristics, as well as BC patients’ overall survival, were statistically assessed. In in vitro culture, MCF-7 and MDA-MB-231 cells were infected with lentivirus to overexpress endogenous miR-588. The subsequent effects of miR-588 upregulation on BC cell proliferation and cisplatin chemosensitivity were examined.

Results

miR-588 was found to be significantly downregulated in both BC cell lines and carcinoma tissues of BC patients. Low expression of miR-588 was closely correlated with BC patients’ poor prognosis of TNM stage, lymph node metastasis, and estrogen receptor status. In addition, patients with low miR-588-expressing carcinomas had much shorter overall survival. In MCF-7 and MDA-MB-231 cells, lentiviral infection induced significant miR-588 upregulation, and miR-588 upregulation had an anti-tumor effect in BC cells by significantly inhibiting cancer proliferation and increasing cisplatin chemosensitivity.

Conclusions

miR-588 is downregulated in BC and its aberrant expression is closely associated with patients’ poor prognosis and overall survival, thus suggesting a biomarker role. miR-588 also has anti-tumor function in BC, making it a potential therapeutic target for BC treatment.

Targeting epithelial-mesenchymal plasticity in cancer: clinical and preclinical advances in therapy and monitoring

The concept of epithelial-mesenchymal plasticity (EMP), which describes the dynamic flux within the spectrum of phenotypic states that invasive carcinoma cells may reside, is being increasingly recognised for its role in cancer progression and therapy resistance. The myriad of events that are able to induce EMP, as well as the more recently characterised control loops, results in dynamic transitions of cancerous epithelial cells to more mesenchymal-like phenotypes through an epithelial-mesenchymal transition (EMT), as well as the reverse transition from mesenchymal phenotypes to an epithelial one. The significance of EMP, in its ability to drive local invasion, generate cancer stem cells and facilitate metastasis by the dissemination of circulating tumour cells (CTCs), highlights its importance as a targetable programme to combat cancer morbidity and mortality. The focus of this review is to consolidate the existing knowledge on the strategies currently in development to combat cancer progression via inhibition of specific facets of EMP. The prevalence of relapse due to therapy resistance and metastatic propensity that EMP endows should be considered when designing therapy regimes, and such therapies should synergise with existing chemotherapeutics to benefit efficacy. To further improve upon EMP-targeted therapies, it is imperative to devise monitoring strategies to assess the impact of such treatments on EMP-related phenomenon such as CTC burden, chemosensitivity/-resistance and micrometastasis in patients.

MicroRNA-409-5p is upregulated in breast cancer and its downregulation inhibits cancer development through downstream target of RSU1

We investigated the expression and function of miR-409-5p in human breast cancer. Quantitative real-time polymerase chain reaction was conducted to evaluate endogenous miR-409-5p expression in breast cancer tumors and breast cancer cell lines. Lentiviral transduction was performed to stably downregulate miR-409-5p in breast cancer cell lines MDA-MB-231 and MCF-7 and cells. The effects of miR-409-5p downregulation on breast cancer proliferation, migration, and xenograft development were then evaluated. Downstream target gene of miR-409-5p, Ras suppressor protein 1, was examined by dual-luciferase activity assay, quantitative real-time polymerase chain reaction, and western blot in lentiviral-transduced breast cancer cells. Ras suppressor protein 1 was also inhibited in miR-409-5p-downregulated breast cancer cells to examine its functional effect on breast cancer proliferation and migration. MiR-409-5p was aberrantly upregulated in both breast cancer tumors and cell lines. Lentiviral transduction successfully downregulated endogenous miR-409-5p expression as well as suppressed proliferation, migration, and xenograft development in MDA-MB-231 and MCF-7 cells. Ras suppressor protein 1 was confirmed to be directly targeted by miR-409-5p in breast cancer cells. Small interfering RNA-mediated Ras suppressor protein 1 inhibition reversely promoted cancer proliferation and migration in miR-409-5p-downregualted breast cancer cells. MiR-409-5p is downregulated in breast cancer and its inhibition has anti-cancer effect on breast cancer development both in vitro and in vivo. The regulatory effect of miR-409-5p inhibition is likely through the inverse upregulation of Ras suppressor protein 1 in breast cancer.

HER2 positivity may confer resistance to therapy with paclitaxel in breast cancer cell lines

INTRODUCTION

MicroRNAs (miRNAs) are short non-coding single-stranded RNAs. Involving in post-transcriptional gene silencing, miRNAs are thought to play important roles in many cancers such as breast cancer. Paclitaxel is used widely in the treatment of breast cancer. In this study, we investigated the effect of paclitaxel treatment on the expression levels of two oncomirs (oncomiRs), miR-21 and miR-203, in breast cancer cell lines.

MATERIALS AND METHODS

MTT assay was performed to determine IC50 of paclitaxel for human breast cancer cell lines including MCF-7, MDA-MB-231, SKBR3 and BT-474. After RNA extraction and cDNA synthesis, the expression levels of miRNAs were then quantitatively evaluated using real-time PCR.

RESULTS

Our results showed that after treatment, the expression levels of both miR-21 and miR-203 were significantly increased in HER2-positive cell lines, BT-474 and SKBR3. HER2-negative cell lines, MCF-7 and MDA-MB-231, in contrast had significantly decreased expression of both assessed oncomiRs.

CONCLUSION

Our results showed that the expression levels of oncomiRs were increased in HER-2 positive breast cancer cells and this finding is in line with previous studies. Our findings present a probable mechanism of resistance against paclitaxel chemotherapy in HER2-positive breast cancers.

Upregulation of microRNA-143 reverses drug resistance in human breast cancer cells via inhibition of cytokine-induced apoptosis inhibitor 1

Cytokine-induced apoptosis inhibitor 1 (CIAPIN1), originally termed anamorsin, is an anti-apoptotic molecule that acts as a downstream effector of the receptor tyrosine kinase-Ras signaling pathway. Overexpression of CIAPIN1 contributes to multidrug resistance (MDR) and microRNA (miR)-143 is typically considered a tumor suppressor in breast cancer. The present study aimed to evaluate the therapeutic potential of miR-143 as a treatment for drug-resistant breast cancer via the downregulation of CIAPIN1 in vitro. The expression levels of miR-143 were measured using quantitative polymerase chain reaction and the expression levels of CIAPIN1 were detected via western blot analysis. Bioinformatic analyses was additionally conducted to search for miR-143, which may potentially target CIAPIN1. Luciferase reporter plasmids were created and used to verify direct targeting. In addition, Taxol-induced drug-resistant (TDR) breast cancer cell proliferation was evaluated using the Cell Counting Kit-8 assay in vitro. The present study identified an inverse association between miR-143 and CIAPIN1 protein expression levels in breast cancer MCF-7, MDA-MB-231 and MDA-MB-453 TDR cells. Specific targeting sites for miR-143 in the 3′-untranslated region of the CIAPIN1 gene were identified, which exhibit the ability to regulate CIAPIN1 expression. It was revealed that the repression of CIAPIN1 via miR-143 suppressed the proliferation of breast cancer TDR cells. The findings of the present study verified the role of miR-143 as a tumor suppressor in breast cancer MDR via inhibition of CIAPIN1 translation.

Clinical Value of miR-101-3p and Biological Analysis of its Prospective Targets in Breast Cancer: A Study Based on The Cancer Genome Atlas (TCGA) and Bioinformatics

Background

MiR-101-3p can promote apoptosis and inhibit proliferation, invasion, and metastasis in breast cancer (BC) cells. However, its mechanisms in BC are not fully understood. Therefore, a comprehensive analysis of the target genes, pathways, and networks of miR-101-3p in BC is necessary.

Material/Methods

The miR-101 profiles for 781 patients with BC from The Cancer Genome Atlas (TCGA) were analyzed. Gene expression profiling of GSE31397 with miR-101-3p transfected MCF-7 cells and scramble control cells was downloaded from Gene Expression Omnibus (GEO), and the differentially expressed genes (DEGs) were identified. The potential genes targeted by miR-101-3p were also predicted. Gene Ontology (GO) and pathway and network analyses were constructed for the DEGs and predicted genes.

Results

In the TCGA data, a low level of miR-101-2 expression might represent a diagnostic (AUC: 0.63) marker, and the miR-101-1 was a prognostic (HR=1.79) marker. MiR-101-1 was linked to the estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2), and miR-101-2 was associated with the tumor (T), lymph node (N), and metastasis (M) stages of BC. Moreover, 427 genes were selected from the 921 DEGs in GEO and the 7924 potential target genes from the prediction databases. These genes were related to transcription, metabolism, biosynthesis, and proliferation. The results were also significantly enriched in the VEGF, mTOR, focal adhesion, Wnt, and chemokine signaling pathways.

Conclusions

MiR-101-1 and miR-101-2 may be prospective biomarkers for the prognosis and diagnosis of BC, respectively, and are associated with diverse clinical parameters. The target genes of miR-101-3p regulate the development and progression of BC. These results provide insight into the pathogenic mechanism and potential therapies for BC.

HIC1 and miR-23~27~24 clusters form a double-negative feedback loop in breast cancer

MicroRNAs (miRNAs) have emerged as a major regulator of the initiation and progression of human cancers, including breast cancer. However, the cooperative effects and transcriptional regulation of multiple miRNAs, especially miRNAs that are present in clusters, remain largely undiscovered. Here we showed that all members of the miR-23~27~24 clusters are upregulated and function as oncogenes in breast cancer and simultaneously target HIC1. Furthermore, we found that HIC1 functions as a transcriptional repressor to negatively control the expression of miR-23~27~24 clusters and forms a double-negative (overall positive) feedback loop. This feedback regulatory pathway is important because overexpression of miR-23~27~24 clusters can remarkably accelerate tumor growth, whereas restoration of HIC1 significantly blocks tumor growth in vivo. A mathematical model was created to quantitatively illustrate the regulatory circuit. Our finding highlights the cooperative effects of miRNAs in a cluster and adds another layer of complexity to the miRNA regulatory network. This study may also provide insight into the molecular mechanisms of breast cancer progression.

miR-124-3p functions as a tumor suppressor in breast cancer by targeting CBL

BACKGROUND

The origin and development of breast cancer remain complex and obscure. Recently, microRNA (miRNA) has been identified as an important regulator of the initiation and progression of breast cancer, and some studies have shown the essential role of miR-124-3p as a tumor suppressor in breast tumorigenesis. However, the detailed role of miR-124-3p in breast cancer remains poorly understood.

METHODS

Quantitative RT-PCR and western blotting assays were used to measure miR-124-3p and CBL expression levels in breast cancer tissues, respectively. Luciferase reporter assay was employed to validate the direct targeting of CBL by miR-124-3p. Cell proliferation and invasion assays were performed to analyze the biological functions of miR-124-3p and CBL in breast cancer cells.

RESULTS

In the present study, we found that miR-124-3p was consistently downregulated in breast cancer tissues. Moreover, we showed that miR-124-3p significantly suppressed the proliferation and invasion of breast cancer cells. In addition, we investigated the molecular mechanism through which miR-124-3p contributes to breast cancer tumorigenesis and identified CBL (Cbl proto-oncogene, E3 ubiquitin protein ligase) as a direct target gene of miR-124-3p. Moreover, we found that ectopic expression of CBL can attenuate the inhibitory effect of miR-124-3p on cell proliferation and invasion in breast cancer cells.

CONCLUSIONS

This study identified a new regulatory axis in which miR-124-3p and CBL regulate the proliferation and invasion of breast cancer cells.

MicroRNA networks regulated by all-trans retinoic acid and Lapatinib control the growth, survival and motility of breast cancer cells

SKBR3-cells, characterized by ERBB2/RARA co-amplification, represent a subgroup of HER2⁺ breast-cancers sensitive to all-trans retinoic acid (ATRA) and Lapatinib. In this model, the two agents alone or in combination modulate the expression of 174 microRNAs (miRs). These miRs and predicted target-transcripts are organized in four interconnected modules (Module-1 to -4). Module-1 and Module-3 consist of ATRA/Lapatinib up-regulated and potentially anti-oncogenic miRs, while Module-2 contains ATRA/Lapatinib down-regulated and potentially pro-oncogenic miRs. Consistent with this, the expression levels of Module-1/-3 and Module-2 miRs are higher and lower, respectively, in normal mammary tissues relative to ductal-carcinoma-in-situ, invasive-ductal-carcinoma and metastases. This indicates associations between tumor-progression and the expression profiles of Module-1 to -3 miRs. Similar associations are observed with tumor proliferation-scores, staging, size and overall-survival using TCGA (The Cancer Genome Atlas) data. Forced expression of Module-1 miRs, (miR-29a-3p; miR-874-3p) inhibit SKBR3-cell growth and Module-3 miRs (miR-575; miR-1225-5p) reduce growth and motility. Module-2 miRs (miR-125a; miR-193; miR-210) increase SKBR3 cell growth, survival and motility. Some of these effects are of general significance, being replicated in other breast cancer cell lines representing the heterogeneity of this disease. Finally, our study demonstrates that HIPK2-kinase and the PLCXD1-phospholipase-C are novel targets of miR-193a-5p/miR-210-3p and miR-575/miR-1225-5p, respectively.

A novel polydopamine-based chemiluminescence resonance energy transfer method for microRNA detection coupling duplex-specific nuclease-aided target recycling strategy

MicroRNAs (miRNAs), functioning as oncogenes or tumor suppressors, play significant regulatory roles in regulating gene expression and become as biomarkers for disease diagnostics and therapeutics. In this work, we have coupled a polydopamine (PDA) nanosphere-assisted chemiluminescence resonance energy transfer (CRET) platform and a duplex-specific nuclease (DSN)-assisted signal amplification strategy to develop a novel method for specific miRNA detection. With the assistance of hemin, luminol, and H2O2, the horseradish peroxidase (HRP)-mimicking G-rich sequence in the sensing probe produces chemiluminescence, which is quickly quenched by the CRET effect between PDA as energy acceptor and excited luminol as energy donor. The target miRNA triggers DSN to partially degrade the sensing probe in the DNA-miRNA heteroduplex to repeatedly release G-quadruplex formed by G-rich sequence from PDA for the production of chemiluminescence. The method allows quantitative detection of target miRNA in the range of 80 pM-50 nM with a detection limit of 49.6 pM. The method also shows excellent specificity to discriminate single-base differences, and can accurately quantify miRNA in biological samples, with good agreement with the result from a commercial miRNA detection kit. The procedure requires no organic dyes or labels, and is a simple and cost-effective method for miRNA detection for early clinical diagnosis.

Downregulation of β3 integrin by miR-30a-5p modulates cell adhesion and invasion by interrupting Erk/Ets‑1 network in triple-negative breast cancer

Integrins are adhesion receptors involved in bidirectional signaling and are crucial for various cellular responses during normal homeostasis and pathological conditions, such as cancer progression and metastasis. In the present study, we demonstrated that blockage of β3 integrin-mediated cell- extracellular matrix interactions restrained triple-negative breast cancer (TNBC) growth, and elevated β3 integrin can trigger the rewiring of Erk/Ets-1 signaling pathways, thereby enhancing cell growth and invasion. Ectopic expression of miRNA has been implicated in the deregulation of integrin expression and activity, blocking of cancer tumor development and progression, and acquisition of metastatic phenotype. miR-30a-5p expression has been implicated in the progression of breast cancer. Overexpression of miR-30a-5p suppressed the proliferation, migration and invasion of breast cancer cells. On the contrary, inhibition of miR-30a-5p promoted the proliferation, migration, and invasion of TNBC cells by suppressing the expression of ERK/Ets-1 signal. An inverse correlation was found between the mRNA expressions of miR-30a-5p and β3 integrin in TNBC samples. Furthermore, bioinformatics analysis revealed the putative miR-30 binding sites in the 3'-UTR of β3 integrin. Results of luciferase assay revealed a strong repression of luciferase activity after transfection with miR‑30a-5p and wild-type 3'-UTR of β3 integrin. In TNBC cells, miR-30a-5p promoted an epithelial phenotype and suppressed invasion by specifically targeting β3 integrin subunit to subsequently interdict the β3 integrin/Erk/Ets-1 network.

MicroRNAs: New Biomarkers for Diagnosis, Prognosis, Therapy Prediction and Therapeutic Tools for Breast Cancer

Dysregulation of microRNAs (miRNAs) is involved in the initiation and progression of several human cancers, including breast cancer (BC), as strong evidence has been found that miRNAs can act as oncogenes or tumor suppressor genes. This review presents the state of the art on the role of miRNAs in the diagnosis, prognosis, and therapy of BC. Based on the results obtained in the last decade, some miRNAs are emerging as biomarkers of BC for diagnosis (i.e., miR-9, miR-10b, and miR-17-5p), prognosis (i.e., miR-148a and miR-335), and prediction of therapeutic outcomes (i.e., miR-30c, miR-187, and miR-339-5p) and have important roles in the control of BC hallmark functions such as invasion, metastasis, proliferation, resting death, apoptosis, and genomic instability. Other miRNAs are of interest as new, easily accessible, affordable, non-invasive tools for the personalized management of patients with BC because they are circulating in body fluids (e.g., miR-155 and miR-210). In particular, circulating multiple miRNA profiles are showing better diagnostic and prognostic performance as well as better sensitivity than individual miRNAs in BC. New miRNA-based drugs are also promising therapy for BC (e.g., miR-9, miR-21, miR34a, miR145, and miR150), and other miRNAs are showing a fundamental role in modulation of the response to other non-miRNA treatments, being able to increase their efficacy (e.g., miR-21, miR34a, miR195, miR200c, and miR203 in combination with chemotherapy).

MicroRNAs are part of the regulatory network that controls EGF induced apoptosis, including elements of the JAK/STAT pathway, in A431 cells

MiRNAs are known to regulate gene expression and in the context of cancer have been shown to regulate metastasis, cell proliferation and cell death. In this report we describe potential miRNA regulatory roles with respect to induction of cell death by pharmacologic dose of Epidermal Growth Factor (EGF). Our previous work suggested that multiple pathways are involved in the induction of apoptosis, including interferon induced genes, cytokines, cytoskeleton and cell adhesion and TP53 regulated genes. Using miRNA time course expression profiling of EGF treated A431 cells and coupling this to our previous gene expression and proteomic data, we have been able to implicate a number of additional miRNAs in the regulation of apoptosis. Specifically we have linked miR-134, miR-145, miR-146b-5p, miR-432 and miR-494 to the regulation of both apoptotic and anti-apoptotic genes expressed as a function of EGF treatment. Whilst additional miRNAs were differentially expressed, these had the largest number of apoptotic and anti-apoptotic targets. We found 5 miRNAs previously implicated in the regulation of apoptosis and our results indicate that an additional 20 miRNAs are likely to be involved based on their correlated expression with targets. Certain targets were linked to multiple miRNAs, including PEG10, BTG1, ID1, IL32 and NCF2. Some miRNAs that target the interferon pathway were found to be down regulated, consistent with a novel layer of regulation of interferon pathway components downstream of JAK/STAT. We have significantly expanded the repertoire of miRNAs that may regulate apoptosis in cancer cells as a result of this work.

Photophysical and structural investigation of a PyA-modified adenine cluster: its potential use for fluorescent DNA probes exhibiting distinct emission color changes

A ^PyA-modified adenine cluster, exhibiting a large Stokes shift based on interstrand stacking interactions of adenines, was investigated and exploited as signaling parts of fluorescent DNA probes.

Bioorthogonal tetrazine-mediated transfer reactions facilitate reaction turnover in nucleic acid-templated detection of microRNA

Tetrazine ligations have proven to be a powerful bioorthogonal technique for the detection of many labeled biomolecules, but the ligating nature of these reactions can limit reaction turnover in templated chemistry. We have developed a transfer reaction between 7-azabenzonorbornadiene derivatives and fluorogenic tetrazines that facilitates turnover amplification of the fluorogenic response in nucleic acid-templated reactions. Fluorogenic tetrazine-mediated transfer (TMT) reaction probes can be used to detect DNA and microRNA (miRNA) templates to 0.5 and 5 pM concentrations, respectively. The endogenous oncogenic miRNA target mir-21 could be detected in crude cell lysates and detected by imaging in live cells. Remarkably, the technique is also able to differentiate between miRNA templates bearing a single mismatch with high signal to background. We imagine that TMT reactions could find wide application for amplified fluorescent detection of clinically relevant nucleic acid templates.

miR-143 and miR-145 synergistically regulate ERBB3 to suppress cell proliferation and invasion in breast cancer

Introduction

ERBB3, one of the four members of the ErbB family of receptor tyrosine kinases, plays an important role in breast cancer etiology and progression. In the present study, we aimed to identify novel miRNAs that can potentially target ERBB3 and their biological functions.

Method

The expression levels of miR-143/145 and target mRNA were examined by relative quantification RT-PCR, and the expression levels of target protein were detected by Western blot. We used bioinformatic analyses to search for miRNAs that can potentially target ERBB3. Luciferase reporter plasmids were constructed to confirm direct targeting. Furthermore, the biological consequences of the targeting of ERBB3 by miR-143/145 were examined by cell proliferation and invasion assays in vitro and by the mouse xenograft tumor model in vivo.

Results

We identified an inverse correlation between miR-143/145 levels and ERBB3 protein levels, but not between miR-143/145 levels and ERBB3 mRNA levels, in breast cancer tissue samples. We identified specific targeting sites for miR-143 and miR-145 (miR-143/145) in the 3’-untranslated region (3’-UTR) of the ERBB3 gene and regulate ERBB3 expression. We demonstrated that the repression of ERBB3 by miR-143/145 suppressed the proliferation and invasion of breast cancer cells, and that miR-143/145 showed an anti-tumor effect by negatively regulating ERBB3 in the xenograft mouse model. Interestingly, miR-143 and miR-145 showed a cooperative repression of ERBB3 expression and cell proliferation and invasion in breast cancer cells, such that the effects of the two miRNAs were greater than with either miR-143 or miR-145 alone.

Conclusion

Taken together, our findings provide the first clues regarding the role of the miR-143/145 cluster as a tumor suppressor in breast cancer through the inhibition of ERBB3 translation. These results also support the idea that different miRNAs in a cluster can synergistically repress a given target mRNA.

Electronic supplementary material

The online version of this article (doi:10.1186/1476-4598-13-220) contains supplementary material, which is available to authorized users.

MicroRNAs in Cancer Biology and Therapy: Current Status and Perspectives

The study of a class of small non-coding RNA molecules, named microRNAs (miRNAs), has advanced our understanding of many of the fundamental processes of cancer biology and the molecular mechanisms underlying tumor initiation and progression. MiRNA research has become more and more attractive as evidence is emerging that miRNAs likely play important regulatory roles virtually in all essential bioprocesses. Looking at this field over the past decade it becomes evident that our understanding of miRNAs remains rather incomplete. As research continues to reveal the mechanisms underlying cancer therapy efficacy, it is clear that miRNAs contribute to responses to drug therapy and are themselves modified by drug therapy. One important area for miRNA research is to understand the functions of miRNAs and the relevant signaling pathways in the initiation, progression and drug-resistance of tumors to be able to design novel, effective targeted therapeutics that directly target pathologically essential miRNAs and/or their target genes. Another area of increasing importance is the use of miRNA signatures in the diagnosis and prognosis of various types of cancers. As the study of non-coding RNAs is increasingly more popular and important, it is without doubt that the next several years of miRNA research will provide more fascinating results.

MicroRNAs in gastric cancer: from benchtop to bedside

Gastric carcinogenesis represents a stepwise progression from chronic inflammation to invasive adenocarcinomas and distant metastasis. It has been widely accepted that these pathologic changes are contributed by aberrant activation or inactivation of protein-coding proto-oncogenes and tumor suppressor genes. However, recent discoveries in microRNA research have reshaped our understanding of the role of non-protein-coding genes in carcinogenesis. MicroRNAs (miRNAs) are a family of 18-25-nucleotide small RNAs that negatively regulate gene expression at the post-transcriptional level during various crucial cell processes such as apoptosis, differentiation and development. Changes in miRNA expression profiles have been observed in a variety of human tumors, including gastric cancer. Further studies demonstrated that miRNAs may function as tumor suppressors and oncogenes. These findings have shown great potential of miRNAs as a novel class of therapeutic targets. In addition, it was found that some miRNAs were directly involved in patients with gastric cancer, including prognosis prediction, treatment selection, and in the search for unknown primary sites. MiRNAs have also been proved to be detectable in serum and plasma. In this review, we summarize the function of miRNAs in gastric cancer. Furthermore, we describe the pathophysiological roles of these miRNAs and their clinical potential as diagnostic biomarkers and therapeutic targets.

Expression of microRNA-497 and its prognostic significance in human breast cancer

Objective

Dysregulation of microRNAs (miRNAs) plays critical roles in tumor progression. The aim of this study was to investigate the clinicopathologic and prognostic significance of miR-497 expression in human breast cancer (BC).

Methods

Taqman qRT-PCR assay was performed to detect the expression of microRNA (miR)-497 in 30 pairs of BC tissues and corresponding noncancerous breast tissues. Additionally, the expression of this miRNA was detected in another 128 BC tissues and its correlations with clinicopathologic features of patients were analyzed. Kaplan-Meier analyses were used to assess survival of patients. Univariate and multivariate analyses were performed using the Cox proportional hazards model to analyze the prognostic significance of miR-497 expression.

Results

Our data indicated that the relative level of miR-497 expression in BC tissues was significantly lower than that in corresponding noncancerous breast tissues (P = 0.0046). Of 128 BC patients, 74 (57.8%) were placed in the high-miR-497 group and 54 (42.2%) were placed in the low-miR-497 group. By statistical analyses, low miR-497 expression was observed to be closely correlated with higher differentiation grade, positive HER-2 expression, higher incidence of lymph node metastasis and advanced clinical stage. Moreover, patients with high miR-497 expression had better 5-year disease-free and overall survival compared with the low miR-497 group (P = 0.0124 and 0.0018, respectively). Univariate and multivariate analyses indicated that low miR-497 expression was an independent poor prognostic factor for BC patients.

Conclusions

Our data provided the first evidence that downregulation of miR-497 was correlated with BC progression, and miR-497 might be a potential molecular biomarker for predicting the prognosis of patients.

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2025828761093488

In vivo monitoring of angiogenesis inhibition via down-regulation of mir-21 in a VEGFR2-luc murine breast cancer model using bioluminescent imaging

MicroRNA-21 (miR-21) is overexpressed in a wide range of cancers and involved in tumor proliferation and metastasis. However, the potential function of miR-21 in regulating tumor angiogenesis has been little disclosed. In this study, we treated the cultured 4T1 murine breast cancer cells and human umbilical vein endothelial cells (HUVECs) with miR-21 mimic, antagomir-21 or negative control (scramble), which were subjected to MTT, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), quantitative Reverse Transcriptase PCR (qRT-PCR) and immunoblotting analysis. In addition, 4T1 cells were implanted beneath the right breast fat pad of the VEGFR2-luc transgenic mice, which were randomly divided into three groups and received saline, antagomir-21 or scramble treatment once respectively after tumor model establishment. Bioluminescent imaging was used to monitor tumor growth and angiogenesis in vivo at 0d, 3d, 5d, 7d, 10d, and 14d after treatment. Mice were killed at the end of study and tumor tissues were collected for use. The results showed that knockdown of miR-21 by antagomir-21 decreased cell proliferation and induced apoptosis via targeting PTEN both in 4T1 cells and HUVECs. We also found the anti-angiogenesis and anti-tumor effects of antagomir-21 in the VEGFR2-luc transgenic mouse model using bioluminescent imaging. Moreover, the Western blotting data revealed that antagomir-21 inhibited tumor angiogenesis through suppressing HIF-1α/VEGF/VEGFR2-associated signaling pathway. In conclusion, the results from current study demonstrate that antagomir-21 can effectively suppress tumor growth and angiogenesis in VEGFR2-luc mouse breast tumor model and bioluminescent imaging can be used as a tool for noninvasively and continuously monitoring tumor angiogenesis in vivo.

Identification of circulating microRNA signatures for breast cancer detection

PURPOSE

There is a quest for novel noninvasive diagnostic markers for the detection of breast cancer. The goal of this study is to identify circulating microRNA (miRNA) signatures using a cohort of Asian Chinese patients with breast cancer, and to compare miRNA profiles between tumor and serum samples.

EXPERIMENTAL DESIGN

miRNA from paired breast cancer tumors, normal tissue, and serum samples derived from 32 patients were comprehensively profiled using microarrays or locked nucleic acid real-time PCR panels. Serum samples from healthy individuals (n = 22) were also used as normal controls. Significant serum miRNAs, identified by logistic regression, were validated in an independent set of serum samples from patients (n = 132) and healthy controls (n = 101).

RESULTS

The 20 most significant miRNAs differentially expressed in breast cancer tumors included miRNA (miR)-21, miR-10b, and miR-145, previously shown to be dysregulated in breast cancer. Only 7 miRNAs were overexpressed in both tumors and serum, suggesting that miRNAs may be released into the serum selectively. Interestingly, 16 of the 20 most significant miRNAs differentially expressed in serum samples were novel. MiR-1, miR-92a, miR-133a, and miR-133b were identified as the most important diagnostic markers, and were successfully validated; receiver operating characteristic curves derived from combinations of these miRNAs exhibited areas under the curves of 0.90 to 0.91.

CONCLUSION

The clinical use of miRNA signatures as a noninvasive diagnostic strategy is promising, but should be further validated for different subtypes of breast cancers.

Pathways to breast cancer recurrence

Breast cancer remains a deadly disease, even with all the recent technological advancements. Early intervention has made an impact, but an overwhelmingly large number of breast cancer patients still live under the fear of “recurrent” disease. Breast cancer recurrence is clinically a huge problem and one that is largely not well understood. Over the years, a number of factors have been studied with an overarching aim of being able to prognose recurrent disease. This paper attempts to provide an overview of our current knowledge of breast cancer recurrence and its associated challenges. Through a survey of the literature on cancer stem cells (CSCs), epithelial-mesenchymal transition (EMT), various signaling pathways such as Notch/Wnt/hedgehog, and microRNAs (miRNAs), we also examine the hypotheses that are currently under investigation for the prevention of breast cancer recurrence.

Personalized medicine in screening for malignant disease: a review of methods and applications

Personalized medicine (PM) is currently a hot topic in the professional world. It is often called the medicine of the future and has already achieved resounding success in the area of targeted therapy. Nevertheless, integration of the concepts of PM into routine clinical practice is slow. This review is intended to give an overview of current and potential applications of PM in oncology. PM could soon play a decisive role, especially in screening. The relevance of PM in screening was examined in the case of four common cancers (colorectal cancer, lung cancer, breast cancer, and prostate cancer). A literature search was performed. This showed that biomarkers in particular play a crucial role in screening. In summary, it can be emphasized that there are already numerous known promising biomarkers in malignant disease. This results in several possibilities for individualizing and revolutionizing screening.

Regulating the Regulators: microRNA and Asthma

One obstacle to developing an effective therapeutic strategy to treat or prevent asthma is that the fundamental causes of asthma are not totally understood. Asthma is thought to be a chronic T_H2 immune-mediated inflammatory disease. Epigenetic changes are recognized to play a role in the initiation and maintenance of a T_H2 response. MicroRNAs (miRNAs) are key epigenetic regulators of gene expression, and their expression is highly regulated, therefore, deregulation of miRNAs may play an important role in the pathogenesis of asthma. Profiling circulating miRNA might provide the highest specificity and sensitivity to diagnose asthma; similarly, correcting potential defects in the miRNA regulation network may lead to new therapeutic modalities to treat this disease.

TFPI alpha and beta regulate mRNAs and microRNAs involved in cancer biology and in the immune system in breast cancer cells

Emerging evidence indicate a new role of TFPI in cancer biology. We recently reported that both isoforms of TFPI induced apoptosis and inhibited proliferation of cancer cells. The signaling pathway(s) mediating the effects of TFPI is, however, presently still unclear. Our goal was to further investigate the cellular processes affected by TFPI and to get insight into the molecular mechanisms involved in the effects of TFPI, using a global gene expression study approach. TFPIα or TFPIβ cDNA were transfected into SK-BR-3 breast cancer cells for stable overexpression. Global mRNA and microRNA (miRNA) expressions were measured and functional annotation of the differentially expressed genes and miRNAs according to gene ontology terms was conducted. Selected results were validated using qRT-PCR and Western blot. A total of 242 and 801 mRNA transcripts and 120 and 46 miRNAs were differentially expressed in cells overexpressing TFPIα or TFPIβ, respectively. Overexpression of either isoform significantly affected the expression of genes involved in cell development (apoptosis, cell movement, migration, invasion, colony formation, growth, and adhesion) and immune response. Network analyses revealed biological interactions between these genes and implied that several of the genes may be involved in both processes. The expression profiles also correlated significantly with clinical phenotype and outcome. Functional cluster analyses indicated altered activity of the epidermal growth factor receptor, small GTPases, and the NF-κB and JAK/STAT cascades when TFPI was overexpressed, and increased activity of the transcription factors NF-κB and Elk-1 and phospho-Akt levels was observed. Integrated mRNA-miRNA analyses showed that 19% and 32% of the differentially expressed genes in cells overexpressing TFPIα or TFPIβ, respectively, may have been regulated by miRNAs. Overexpression of TFPI in breast cancer cells affected the expression of mRNAs and miRNAs involved in processes facilitating cancer cell growth and immunologic response, possibly by signal transduction involving the EGFR pathway.