MicroRNA deregulation in triple negative breast cancer reveals a role of miR-498 in regulating BRCA1 expression

Connection between MiR-490 and CCND1 and GSK3β genes play an effective role in Wnt signaling pathway in colorectal cancer

The Wnt signaling pathway is identified as one of the main disrupted pathways in Colorectal cancer (CRC). Results from studies focusing on this route will aid greatly in the detection and treatment of CRC. MicroRNAs (MiRs), particularly MiR-490, has emerged as key regulator of gene expression in biological pathways, making it an attractive research target. This is notably true for the Wnt signaling pathway, which is usually disordered in CRC tissues. This study aimed to evaluate the expression level of MiR-490 isomiRs and determine some of its key target genes involved in Wnt signaling pathway in CRC tissues and cell lines, based on experimental and bioinformatics analysis. Elevated expression of GSK3β and CCND1 indicate that the progression of CRC tumor is associated with the inhibitory effect of MiR-490 isomiRs on the Wnt/β-catenin signaling pathway. This finding was supported by the observation of a positive connection between the expression pattern of miR-490-3p and 5p, and CCND1 and GSK3β in CRC. The valuable results of this study provide a means of identifying biomarkers with the potential to either inhibit or activate CRC cellular pathways.

MicroRNA signatures differentiate types, grades, and stages of breast invasive ductal carcinoma (IDC): miRNA-target interacting signaling pathways

BACKGROUND

Invasive ductal carcinoma (IDC) is the most common form of breast cancer which accounts for 85% of all breast cancer diagnoses. Non-invasive and early stages have a better prognosis than late-stage invasive cancer that has spread to lymph nodes. The involvement of microRNAs (miRNAs) in the initiation and progression of breast cancer holds great promise for the development of molecular tools for early diagnosis and prognosis. Therefore, developing a cost effective, quick and robust early detection protocol using miRNAs for breast cancer diagnosis is an imminent need that could strengthen the health care system to tackle this disease around the world.

METHODS

We have analyzed putative miRNAs signatures in 100 breast cancer samples using two independent high fidelity array systems. Unique and common miRNA signatures from both array systems were validated using stringent double-blind individual TaqMan assays and their expression pattern was confirmed with tissue microarrays and northern analysis. In silico analysis were carried out to find miRNA targets and were validated with q-PCR and immunoblotting. In addition, functional validation using antibody arrays was also carried out to confirm the oncotargets and their networking in different pathways. Similar profiling was carried out in Brca2/p53 double knock out mice models using rodent miRNA microarrays that revealed common signatures with human arrays which could be used for future in vivo functional validation.

RESULTS

Expression profile revealed 85% downregulated and 15% upregulated microRNAs in the patient samples of IDC. Among them, 439 miRNAs were associated with breast cancer, out of which 107 miRNAs qualified to be potential biomarkers for the stratification of different types, grades and stages of IDC after stringent validation. Functional validation of their putative targets revealed extensive miRNA network in different oncogenic pathways thus contributing to epithelial-mesenchymal transition (EMT) and cellular plasticity.

CONCLUSION

This study revealed potential biomarkers for the robust classification as well as rapid, cost effective and early detection of IDC of breast cancer. It not only confirmed the role of these miRNAs in cancer development but also revealed the oncogenic pathways involved in different progressive grades and stages thus suggesting a role in EMT and cellular plasticity during breast tumorigenesis per se and IDC in particular. Thus, our findings have provided newer insights into the miRNA signatures for the classification and early detection of IDC.

Cancer Pathways Targeted by Berberine: Role of microRNAs

Cancer is a complex and heterogeneous malignant disease. Due to its multifactorial nature, including progressive changes in genetic, epigenetic, transcript, and protein levels, conventional therapeutics fail to save cancer patients. Evidence indicates that dysregulation of microRNA (miRNA) expression plays a crucial role in tumorigenesis, metastasis, cell proliferation, differentiation, metabolism, and signaling pathways. Moreover, miRNAs can be used as diagnostic and prognostic markers and therapeutic targets in cancer. Berberine, a naturally occurring plant alkaloid, has a wide spectrum of biological activities in different types of cancers. Inhibition of cell proliferation, metastasis, migration, invasion, and angiogenesis, as well as induction of cell cycle arrest and apoptosis in cancer cells, is reported by berberine. Recent studies suggested that berberine regulates many oncogenic and tumor suppressor miRNAs implicated in different phases of cancer. This review discussed how berberine inhibits cancer growth and propagation and regulates miRNAs in cancer cells. And how berberine-mediated miRNA regulation changes the landscape of transcripts and proteins that promote or suppress cancer progression. Overall, the underlying molecular pathways altered by berberine and miRNA influencing the tumor pathophysiology will enhance our understanding to combat the malignancy.

Unveiling the vulnerabilities of synthetic lethality in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is the most invasive molecular subtype of breast cancer (BC), accounting for about nearly 15% of all BC cases reported annually. The absence of the three major BC hormone receptors, Estrogen (ER), Progesterone (PR), and Human Epidermal Growth Factor 2 (HER2) receptor, accounts for the characteristic "Triple negative" phraseology. The absence of these marked receptors makes this cancer insensitive to classical endocrine therapeutic approaches. Hence, the available treatment options remain solemnly limited to only conventional realms of chemotherapy and radiation therapy. Moreover, these therapeutic regimes are often accompanied by numerous treatment side-effects that account for early distant metastasis, relapse, and shorter overall survival in TNBC patients. The rigorous ongoing research in the field of clinical oncology has identified certain gene-based selective tumor-targeting susceptibilities, which are known to account for the molecular fallacies and mutation-based genetic alterations that develop the progression of TNBC. One such promising approach is synthetic lethality, which identifies novel drug targets of cancer, from undruggable oncogenes or tumor-suppressor genes, which cannot be otherwise clasped by the conventional approaches of mutational analysis. Herein, a holistic scientific review is presented, to undermine the mechanisms of synthetic lethal (SL) interactions in TNBC, the epigenetic crosstalks encountered, the role of Poly (ADP-ribose) polymerase inhibitors (PARPi) in inducing SL interactions, and the limitations faced by the lethal interactors. Thus, the future predicament of synthetic lethal interactions in the advancement of modern translational TNBC research is assessed with specific emphasis on patient-specific personalized medicine.

HBx promotes hepatocellular carcinoma progression by repressing the transcription level of miR-187-5p

HBV-associated hepatitis B virus x protein (HBx) plays multiple roles in the development of hepatocellular carcinoma. In our prior study, we discovered that miR-187-5p expression was inhibited by HBx. To investigate the underlying molecular mechanism of HBx-mediated miR-187-5p downregulation in hepatocellular carcinoma cells, effects of HBx and miR-187-5p on hepatoma carcinoma cell were observed, as well as their interactions. Through in vitro and in vivo experiments, we demonstrated that overexpression of miR-187-5p inhibited proliferation, migration, and invasion. Simultaneously, we observed a dysregulation in the expression of miR-187-5p in liver cancer cell lines, which may be attributed to transcriptional inhibition through the E2F1/FoxP3 axis. Additionally, we noted that HBx protein is capable of enhancing the expression of E2F1, a transcription factor that promotes the expression of FoxP3. In conclusion, our results suggest that the inhibitory effect of HBx on miR-187-5p is mediated through the E2F1/FoxP3 axis. As shown in this work, HBx promotes hepatoma carcinoma cell proliferation, migration, and invasion through the E2F1/FoxP3/miR-187 axis. It provides a theoretical basis for finding therapeutic targets that will help clinic treatment for HCC.

miRNA deregulation and relationship with metabolic parameters after Mediterranean dietary intervention in BRCA-mutated women

Background

Breast cancer onset is determined by a genetics-environment interaction. BRCA1/2 gene alterations are often genetically shared in familial context, but also food intake and hormonal assessment seem to influence the lifetime risk of developing this neoplasia. We previously showed the relationship between a six-months Mediterranean dietary intervention and insulin, glucose and estradiol levels in BRCA1/2 carrier subjects. The aim of the present study was to evidence the eventual influence of this dietary intervention on the relationship between circulating miRNA expression and metabolic parameters in presence of BRCA1/2 loss of function variants.

Methods

Plasma samples of BRCA-women have been collected at the baseline and at the end of the dietary intervention. Moreover, subjects have been randomized in two groups: dietary intervention and placebo. miRNA profiling and subsequent ddPCR validation have been performed in all the subjects at both time points.

Results

ddPCR analysis confirmed that five (miR-185-5p, miR-498, miR-3910, miR-4423 and miR-4445) of seven miRNAs, deregulated in the training cohort, were significantly up-regulated in subjects after dietary intervention compared with the baseline measurement. Interestingly, when we focused on variation of miRNA levels in the two timepoints, it could be observed that miR-4423, miR-4445 and miR-3910 expressions are positively correlated with variation in vitaminD level; whilst miR-185-5p difference in expression is related to HDL cholesterol variation.

Conclusions

We highlighted the synergistic effect of a healthy lifestyle and epigenetic regulation in BC through the modulation of specific miRNAs. Different miRNAs have been reported involved in the tumor onset acting as tumor suppressors by targeting tumor-associated genes that are often downregulated.

Identification of novel miRNAs potentially involved in the pathogenesis of adult T-cell leukemia/lymphoma using WGCNA followed by RT-qPCR test of hub genes

BACKGROUND

Adult T-cell Lymphoma/Leukemia (ATLL) is characterized by the malignant proliferation of T-cells in Human T-Lymphotropic Virus Type 1 and a high mortality rate. Considering the emerging roles of microRNAs (miRNAs) in various malignancies, the analysis of high-throughput miRNA data employing computational algorithms helps to identify potential biomarkers.

METHODS

Weighted gene co-expression network analysis was utilized to analyze miRNA microarray data from ATLL and healthy uninfected samples. To identify miRNAs involved in the progression of ATLL, module preservation analysis was used. Subsequently, based on the target genes of the identified miRNAs, the STRING database was employed to construct protein-protein interaction networks (PPIN). Real-time quantitative PCR was also performed to validate the expression of identified hub genes in the PPIN network.

RESULTS

After constructing co-expression modules and then performing module preservation analysis, four out of 15 modules were determined as ATLL-specific modules. Next, the hub miRNA including hsa-miR-18a-3p, has-miR-187-5p, hsa-miR-196a-3p, and hsa-miR-346 were found as hub miRNAs. The protein-protein interaction networks were constructed for the target genes of each hub miRNA and hub genes were identified. Among them, UBB, RPS15A, and KMT2D were validated by Reverse-transcriptase PCR in ATLL patients.

CONCLUSION

The results of the network analysis of miRNAs and their target genes revealed the major players in the pathogenesis of ATLL. Further studies are required to confirm the role of these molecular factors and to discover their potential benefits as treatment targets and diagnostic biomarkers.

Rheumatoid arthritis and risk of site-specific cancers: Mendelian randomization study in European and East Asian populations

BACKGROUND

The associations of rheumatoid arthritis (RA) with risk of site-specific cancers beyond lymphohematopoietic cancer have been scarcely explored. We conducted a Mendelian randomization investigation of the associations of RA with site-specific cancers in European and East Asian populations.

METHODS

Independent genetic variants strongly associated with RA in European and East Asian populations were selected as instrumental variables from genome-wide association studies of 58,284 European individuals (14,361 cases and 43,923 controls) and 22,515 East Asian individuals (4873 cases and 17,642 controls), respectively. The associations of genetic variants with overall and 22 site-specific cancers were extracted from the UK Biobank study (n = 367,561), the FinnGen study (n = 260,405), Biobank Japan (n = 212,453), and international consortia. The associations for one outcome from different data sources were combined by meta-analysis.

RESULTS

In the European population, the combined odds ratios per 1-unit increase in log odds of genetic liability to RA were 1.06 (95% confidence interval [CI] 1.03-1.10) for head and neck cancer, 1.06 (95% CI 1.02-1.10) for cervical cancer, 0.92 (95% CI 0.87-0.96) for testicular cancer, and 0.94 (95% CI 0.90-0.98) for multiple myeloma. In the East Asian population, the corresponding odds ratios were 1.17 (95% CI 1.06-1.29) for pancreatic cancer, 0.91 (95% CI 0.88-0.94) for breast cancer, and 0.90 (95% CI 0.84-0.96) for ovarian cancer. There were suggestive associations for breast and ovarian cancer and overall cancer in the European population. No other associations were observed.

CONCLUSION

This study suggests that RA may play a role in the development of several site-specific cancers.

Investigation of BRCAness associated miRNA-gene axes in breast cancer: cell-free miR-182-5p as a potential expression signature of BRCAness

The concept of the ‘BRCAness’ phenotype implies the properties that some sporadic breast cancers (BC) share with BRCA1/2-mutation carriers with hereditary BC. Breast tumors with BRCAness have deficiencies in homologous recombination repair (HRR), like BRCA1/2-mutation carriers, and consequently could benefit from poly-(ADP)-ribose polymerase (PARP) inhibitors and DNA-damaging chemotherapy. Triple-negative breast cancers (TNBC) show a higher frequency of BRCAness than the other BC subtypes. Therefore, looking for BRCAness-related biomarkers could improve personalized management of TNBC patients. microRNAs (miRNAs) play a pivotal role in onco-transcriptomic profiles of tumor cells besides their suitable features as molecular biomarkers. The current study aims to evaluate the expression level of some critical miRNAs-mRNA axes in HRR pathway in tumors and plasma samples from BC patients. The expression levels of three multi-target miRNAs, including miR-182-5p, miR-146a-5p, and miR-498, as well as six downstream HRR-related protein-coding genes, have been investigated in the breast tumors and paired adjacent normal tissues by Real-time PCR. In the next step, based on the results derived from the previous step, we examined the level of cell-free miR-182-5p in the blood plasma samples from the patients. Our results highlight the difference between TNBC and non-TNBC tumor subgroups regarding the dysregulation of the key miRNA/mRNA axes involved in the HRR pathway. Also, for the first time, we show that the level of cell-free miR-182-5p in plasma samples from BC patients could be a clue for screening BC patients eligible for receiving PARP inhibitors through a personalized manner. Altogether, some sporadic BC patients, especially sporadic TNBC, have epigenetically dysregulated HRR pathway that could be identified and benefit from BRCAness-specific therapeutic agents.

Interactions between miRNAs and Double-Strand Breaks DNA Repair Genes, Pursuing a Fine-Tuning of Repair

The repair of DNA damage is a crucial process for the correct maintenance of genetic information, thus, allowing the proper functioning of cells. Among the different types of lesions occurring in DNA, double-strand breaks (DSBs) are considered the most harmful type of lesion, which can result in significant loss of genetic information, leading to diseases, such as cancer. DSB repair occurs through two main mechanisms, called non-homologous end joining (NHEJ) and homologous recombination repair (HRR). There is evidence showing that miRNAs play an important role in the regulation of genes acting in NHEJ and HRR mechanisms, either through direct complementary binding to mRNA targets, thus, repressing translation, or by targeting other genes involved in the transcription and activity of DSB repair genes. Therefore, alteration of miRNA expression has an impact on the ability of cells to repair DSBs, which, in turn, affects cancer therapy sensitivity. This latter gives account of the importance of miRNAs as regulators of NHEJ and HRR and places them as a promising target to improve cancer therapy. Here, we review recent reports demonstrating an association between miRNAs and genes involved in NHEJ and HRR. We employed the Web of Science search query TS (“gene official symbol/gene aliases*” AND “miRNA/microRNA/miR-”) and focused on articles published in the last decade, between 2010 and 2021. We also performed a data analysis to represent miRNA–mRNA validated interactions from TarBase v.8, in order to offer an updated overview about the role of miRNAs as regulators of DSB repair.

miR-498 Targets UBE2T to Inhibit the Proliferation of Malignant Melanoma Cells

Background: Malignant melanoma is a common malignant tumor and one of the tumors with the fastest growing incidence. The effect of microRNAs on the biological processing of malignant melanoma cells also have been reported. This study explores the ability of miR-498 to regulate the progression of malignant melanoma cells. Methods: The expression of miR-498 was detected by RT-qPCR. The proliferation, invasion, and migration of malignant melanoma cells were measured by cell counting kit-8, clone formation, and transwell assays. Flow cytometry assay detected the percentage of apoptotic cells. Western blot was used to detect the expression of markers related to epithelial-mesenchymal transition. The correction of miR-498 and UBE2T was explored by dual-luciferase assay and Western blot. Results: Overexpression of miR-498 inhibited the proliferation, invasion, migration, and induced cell apoptosis of M14 and A375 cells. In addition, the expression of epithelial-mesenchymal transition-related factors was altered by the overexpression of miR-498. miR-498 can directly target UBE2T 3'-UTR and inhibit UBE2T protein expression. The overexpression of UBE2T reversed the inhibitory effects of miR-498 on the progression of malignant melanoma cells. Furthermore, UBE2T mRNA was significantly highly expressed in malignant melanoma tissues. The high expression of UBE2T was associated with the poor overall survival rate of malignant melanoma patients. Conclusions: Altogether, our findings demonstrated that miR-498 significantly inhibited the proliferation, invasion, migration, and induced apoptosis of malignant melanoma cells and confirmed that miR-498 regulated malignant melanoma cell progression by targeting UBE2T.

CDX2 inducible microRNAs sustain colon cancer by targeting multiple DNA damage response pathway factors

Meta-analysis of transcripts in colon adenocarcinoma patient tissues led to the identification of a DNA damage responsive miR signature called DNA damage sensitive miRs (DDSMs). DDSMs were experimentally validated in the cancerous colon tissues obtained from an independent cohort of colon cancer patients and in multiple cellular systems with high levels of endogenous DNA damage. All the tested DDSMs were transcriptionally upregulated by a common intestine-specific transcription factor, CDX2. Reciprocally, DDSMs were repressed via the recruitment of HDAC1/2-containing complexes onto the CDX2 promoter. These miRs downregulated multiple key targets in the DNA damage response (DDR) pathway, namely BRCA1, ATM, Chk1 (also known as CHEK1) and RNF8. CDX2 directly regulated the DDSMs, which led to increased tumor volume and metastasis in multiple preclinical models. In colon cancer patient tissues, the DDSMs negatively correlated with BRCA1 levels, were associated with decreased probability of survival and thereby could be used as a prognostic biomarker. This article has an associated First Person interview with the first author of the paper.

Long non-coding RNA (lncRNA) HOXB-AS3 promotes cell proliferation and inhibits apoptosis by regulating ADAM9 expression through targeting miR-498-5p in endometrial carcinoma

Objective

Long non-coding RNA (lncRNA) expression is closely related to the pathogenesis and progression of various tumors. In this study, we investigated the mechanisms of lncRNA HOXB cluster antisense RNA 3 (HOXB-AS3), miRNA(miR)-498-5p, and disintegrin and metalloproteinase domain-containing protein 9 (ADAM9) in endometrial carcinoma (EC) cells.

Methods

The expression levels of lncRNA HOXB-AS3 in EC tissues and cells were detected using RT-qPCR assays. The effects of HOXB-AS3 knockdown on EC cell proliferation and apoptosis were measured using CCK-8 assays, colony formation assays, and flow cytometry. In addition, putative miR-498-5p binding sites were identified in HOXB-AS3 and ADAM9. The targeted relationships were further verified using dual-luciferase reporter and RNA pull-down assays.

Results

HOXB-AS3 expression was upregulated in EC tissues and cells. EC cell proliferation and viability decreased significantly in HOXB-AS3 knockdown groups. A putative miR-498-5p binding site in HOXB-AS3 was verified. Inhibition of miR-498-5p rescued the effects of HOXB-AS3 knockdown on cell proliferation and apoptosis. Finally, ADAM9 was verified as a direct target gene of miR-498-5p.

Conclusions

Our results suggest that lncRNA HOXB-AS3 is highly expressed in EC tissues and cells. Downregulation of HOXB-AS3 inhibits cell proliferation and promotes apoptosis in EC cells. HOXB-AS3 can upregulate ADAM9 expression by sponging miR-498-5p.

The Anticancer Effects of Flavonoids through miRNAs Modulations in Triple-Negative Breast Cancer

Triple- negative breast cancer (TNBC) incidence rate has regularly risen over the last decades and is expected to increase in the future. Finding novel treatment options with minimum or no toxicity is of great importance in treating or preventing TNBC. Flavonoids are new attractive molecules that might fulfill this promising therapeutic option. Flavonoids have shown many biological activities, including antioxidant, anti-inflammatory, and anticancer effects. In addition to their anticancer effects by arresting the cell cycle, inducing apoptosis, and suppressing cancer cell proliferation, flavonoids can modulate non-coding microRNAs (miRNAs) function. Several preclinical and epidemiological studies indicate the possible therapeutic potential of these compounds. Flavonoids display a unique ability to change miRNAs' levels via different mechanisms, either by suppressing oncogenic miRNAs or activating oncosuppressor miRNAs or affecting transcriptional, epigenetic miRNA processing in TNBC. Flavonoids are not only involved in the regulation of miRNA-mediated cancer initiation, growth, proliferation, differentiation, invasion, metastasis, and epithelial-to-mesenchymal transition (EMT), but also control miRNAs-mediated biological processes that significantly impact TNBC, such as cell cycle, immune system, mitochondrial dysregulation, modulating signaling pathways, inflammation, and angiogenesis. In this review, we highlighted the role of miRNAs in TNBC cancer progression and the effect of flavonoids on miRNA regulation, emphasizing their anticipated role in the prevention and treatment of TNBC.

Role and mechanism of miR-187 in human cancer

MicroRNAs (miRNAs) are short non-coding RNAs, approximately 22 nucleotides in length, and involved in the post-transcriptional regulation of gene expression. MiRNAs play fundamental roles in many biological processes such as the development and progression of tumors. In this review, we briefly describe the expression of miR-187 in various types of cancer and discuss the role of miR-187 in cancer development and drug resistance. It is also possible to take miR-187 as an important indicator of diagnosis and prognosis of tumors.

BRCA1 Promoter Hypermethylation is Associated with Good Prognosis and Chemosensitivity in Triple-Negative Breast Cancer

The aberrant hypermethylation of BRCA1 promoter CpG islands induces the decreased expression of BRCA1 (Breast Cancer 1) protein. It can be detected in sporadic breast cancer without BRCA1 pathogenic variants, particularly in triple-negative breast cancers (TNBC). We investigated BRCA1 hypermethylation status (by methylation-specific polymerase chain reaction (MS-PCR) and MassARRAY^® assays), and BRCA1 protein expression using immunohistochemistry (IHC), and their clinicopathological significance in 248 chemotherapy-naïve TNBC samples. Fifty-five tumors (22%) exhibited BRCA1 promoter hypermethylation, with a high concordance rate between MS-PCR and MassARRAY^® results. Promoter hypermethylation was associated with reduced IHC BRCA1 protein expression (p = 0.005), and expression of Programmed death-ligand 1 protein (PD-L1) by tumor and immune cells (p = 0.03 and 0.011, respectively). A trend was found between promoter hypermethylation and basal marker staining (p = 0.058), and between BRCA1 expression and a basal-like phenotype. In multivariate analysis, relapse-free survival was significantly associated with N stage, adjuvant chemotherapy, and histological subtype. Overall survival was significantly associated with T and N stage, histology, and adjuvant chemotherapy. In addition, patients with tumors harboring BRCA1 promoter hypermethylation derived the most benefit from adjuvant chemotherapy. In conclusion, BRCA1 promoter hypermethylation is associated with TNBC sensitivity to adjuvant chemotherapy, basal-like features and PD-L1 expression. BRCA1 IHC expression is not a good surrogate marker for promoter hypermethylation and is not independently associated with prognosis. Association between promoter hypermethylation and sensitivity to Poly(ADP-ribose) polymerase PARP inhibitors needs to be evaluated in a specific series of patients.

MicroRNAs, DNA damage response and ageing

Ageing is a multifactorial and integrated gradual deterioration affecting the most of biological process of cells. MiRNAs are differentially expressed in the cellular senescence and play important role in regulating of genes expression involved in features of ageing. The perception of miRNAs functions in ageing regulation can be useful in clarifying the mechanisms underlying ageing and designing of therapeutic strategies. The preservation of genomic integrity through DNA damage response (DDR) is related to the process of cellular senescence. The recent studies have shown that miRNAs has directly regulated the expression of numerous proteins in DDR pathways. In this review study, DDR pathways, miRNA biogenesis and functions, current finding on DDR regulations, molecular biology of ageing and the role of miRNAs in these processes have been studied. Finally, a brief explanation about the therapeutic function of miRNAs in ageing regarding its regulation of DDR has been provided.

Up-regulation of miR-498 inhibits cell proliferation, invasion and migration of hepatocellular carcinoma by targeting FOXO3

BACKGROUND

To unravel the fundamental role of miR-498 in the context of hepatocellular carcinoma cells and understands underlying potential mechanism.

METHODS

Relative viability was interrogated using MTT method and cell proliferation was determined with colony formation assay. The protein levels of cleaved Caspase-3, Bcl-2, Cyclin D, CDK4, FOXO3 and β-actin were analyzed by western blotting. Cell invasion and migration was evaluated by transwell assay and wound healing, respectively. The relative abundance of Cyclin D, CDK4, FOXO3 and miR-498 transcripts was measured using real-time PCR. The regulatory action of miR-498 on FOXO3 expression was analyzed with luciferase reporter.

RESULTS

Ectopic over-expression of miR-498 significantly inhibited viability and proliferation, suppressed cell migration and invasion, delayed cell cycle progression. We further identified FOXO3 as downstream target gene of miR-498, and positively modulated FOXO3 translation in miR-498-proficient cells consequently contributed to its anti-tumoral properties.

CONCLUSIONS

Our data highlighted the tumor suppressor role of miR-498-FOXO3 signaling in hepatocellular carcinoma cells, which might hold promise for therapeutic exploitation.

Therapeutic potential of antagomiRs in haematological and oncological neoplasms

BACKGROUND

The importance of the role of MicroRNAs (or miRNAs) has been emphasised by the large number of studies in human tumour cells, underlining the high impact of post-transcriptional processes in cancer onset, progression, invasion and metastatisation. Currently known as oncomiR, real databases are collecting all the smaller fragments of RNA capable of participating in the oncogenesis.

AIMS

With the aim to collect for the first time the most important acquisitions in literature about antagomiRs in oncology, our narrative review is born with the purpose of showing that specific antisense oligonucleotides, capable to bind and antagonise single or multiple miRNAs, are effective as therapeutic compounds.

RESULTS

Peptide or locked nucleic acids, miRNA sponges or antagomiRs attached to plasmid or lentiviral vectors carrying miRNA sequences to its target are objects of our analysis, demonstrating their effectiveness in a large number and types of tumours. We have also tried how to overcome their high immunogenicity, which remains its greatest limit for clinical use.

CONCLUSIONS

They are ambitious but fascinating promise to alter the promotion of the tumour growth by binding specific molecular targets, with high precision and low toxicity, leaving the scientists the chance of development as anti-cancer drugs and not just.

MicroRNAs Involved in Carcinogenesis, Prognosis, Therapeutic Resistance and Applications in Human Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is the most aggressive, prevalent, and distinct subtype of breast cancer characterized by high recurrence rates and poor clinical prognosis, devoid of both predictive markers and potential therapeutic targets. MicroRNAs (miRNA/miR) are a family of small, endogenous, non-coding, single-stranded regulatory RNAs that bind to the 3′-untranslated region (3′-UTR) complementary sequences and downregulate the translation of target mRNAs as post-transcriptional regulators. Dysregulation miRNAs are involved in broad spectrum cellular processes of TNBC, exerting their function as oncogenes or tumor suppressors depending on their cellular target involved in tumor initiation, promotion, malignant conversion, and metastasis. In this review, we emphasize on masses of miRNAs that act as oncogenes or tumor suppressors involved in epithelial–mesenchymal transition (EMT), maintenance of stemness, tumor invasion and metastasis, cell proliferation, and apoptosis. We also discuss miRNAs as the targets or as the regulators of dysregulation epigenetic modulation in the carcinogenesis process of TNBC. Furthermore, we show that miRNAs used as potential classification, prognostic, chemotherapy and radiotherapy resistance markers in TNBC. Finally, we present the perspective on miRNA therapeutics with mimics or antagonists, and focus on the challenges of miRNA therapy. This study offers an insight into the role of miRNA in pathology progression of TNBC.

Integrated network analysis identifies hsa-miR-4756-3p as a regulator of FOXM1 in Triple Negative Breast Cancer

Both aberrantly expressed mRNAs and micro(mi)RNAs play important roles in cancer cell function, which makes integration analysis difficult. In this study, we first applied master regulator analysisalgorithm and confirmed hsa-miR-4756-3p as a candidate miRNA in triple negative breast cancer (TNBC) patients; hsa-miR-4756-3p could regulate TNBC cell line apoptosis, proliferation, migration, and cell cycle as well as suppress TGF-β1 signalling andtumour growth. In TNBC, forkhead box protein M1 (FOXM1)was found to be an hsa-miR-4756-3p target gene, and FOXM1 knockout completely inhibited hsa-miR-4756-3p-induced cell migration and metastasis, TGF-β1 signalling, and epithelial mesenchymal signal activation, which indicated that hsa-miR-4756-3p functions via the FOXM1-TGFβ1-EMT axis.

HNRNPA2/B1 is upregulated in endocrine-resistant LCC9 breast cancer cells and alters the miRNA transcriptome when overexpressed in MCF-7 cells

MicroRNAs are dysregulated in breast cancer. Heterogeneous Nuclear Ribonucleoprotein A2/B1 (HNRNPA2/B1) is a reader of the N(6)-methyladenosine (m6A) mark in primary-miRNAs (pri-miRNAs) and promotes DROSHA processing to precursor-miRNAs (pre-miRNAs). We examined the expression of writers, readers, and erasers of m6A and report that HNRNPA2/B1 expression is higher in tamoxifen-resistant LCC9 breast cancer cells as compared to parental, tamoxifen-sensitive MCF-7 cells. To examine how increased expression of HNRNPA2/B1 affects miRNA expression, HNRNPA2/B1 was transiently overexpressed (~5.4-fold) in MCF-7 cells for whole genome miRNA profiling (miRNA-seq). 148 and 88 miRNAs were up- and down-regulated, respectively, 48 h after transfection and 177 and 172 up- and down-regulated, respectively, 72 h after transfection. MetaCore Enrichment analysis identified progesterone receptor action and transforming growth factor β (TGFβ) signaling via miRNA in breast cancer as pathways downstream of the upregulated miRNAs and TGFβ signaling via SMADs and Notch signaling as pathways of the downregulated miRNAs. GO biological processes for mRNA targets of HNRNPA2/B1-regulated miRNAs included response to estradiol and cell-substrate adhesion. qPCR confirmed HNRNPA2B1 downregulation of miR-29a-3p, miR-29b-3p, and miR-222 and upregulation of miR-1266-5p, miR-1268a, miR-671-3p. Transient overexpression of HNRNPA2/B1 reduced MCF-7 sensitivity to 4-hydroxytamoxifen and fulvestrant, suggesting a role for HNRNPA2/B1 in endocrine-resistance.

MicroRNA-498 promotes proliferation and migration by targeting the tumor suppressor PTEN in breast cancer cells

Triple negative breast cancer (TNBC) is a subtype of breast cancer with a poor prognosis and high mortality rate. The tumor suppressor phosphatase and tensin homolog deleted on chromosome 10 (PTEN) plays an important role in cell proliferation and cell migration by negatively regulating the PI3K/Akt pathway. PTEN is downregulated by microRNAs in multiple cancers. However, few microRNAs have been reported to directly target PTEN in TNBC. In this study, microRNAs predicted to target PTEN were screened by immunoblotting and luciferase reporter assays. Expression levels of microRNA-498 (miR-498) were measured by TaqMan microRNA assays. We performed clonogenic, cell cycle and scratch wound assays to examine the oncogenic role of miR-498. We demonstrated that miR-498 directly targeted the 3'untranslated region of PTEN mRNA and reduced PTEN protein levels in TNBC cells. Compared with the non-tumorigenic breast epithelial cell line MCF-10A, TNBC cell lines overexpressed miR-498. Moreover, miR-498 promoted cell proliferation and cell cycle progression in TNBC cells in a PTEN-dependent manner. Suppressing miR-498 overexpression impaired the oncogenic effects of miR-498 on cell proliferation and cell migration. This study identified a novel microRNA (miR-498) overexpressed in TNBC cells and its oncogenic role in suppressing PTEN. These results provide new insight into the downregulation of PTEN and indicate a potential therapeutic target for treating TNBC.

Blood Circulating miRNAs as Cancer Biomarkers for Diagnosis and Surgical Treatment Response

miRNAs can function as potential oncogenes or tumor suppressors. Altered expression of these molecules was correlated with the occurrence of many cancer diseases and therefore they are considered a molecular tool for non-invasive cancer diagnosis and prognosis. We searched for analyses concerning expression of blood circulating miRNA in cancer patients. The studies comprised of at least two miRNA expression measurements: before and after the surgical therapy were considered. We summarized latest reports on evaluation of the efficiency of anticancer therapy through observation of changes in expression of miRNA circulating in blood of patients treated with surgery alone. Twenty one research studies were identified. Thirty one different miRNAs were pointed out as potential both diagnostic and treatment response biomarkers since their deregulated expression before therapy returned to normal after receiving the treatment. Published data revealed a potential of circulating miRNA to become a tool giving a clinical follow up information on the efficiency of applied therapy. However, more observational studies on post-operative circulating miRNA expression changes are necessary.

MicroRNA replacement therapy in cancer

Despite the recent progress in cancer management approaches, the mortality rate of cancer is still growing and there are lots of challenges in the clinics in terms of novel therapeutics. MicroRNAs (miRNA) are regulatory small noncoding RNAs and are already confirmed to have a great role in regulating gene expression level by targeting multiple molecules that affect cell physiology and disease development. Recently, miRNAs have been introduced as promising therapeutic targets for cancer treatment. Regulatory potential of tumor suppressor miRNAs, which enables regulation of entire signaling networks within the cells, makes them an interesting option for developing cancer therapeutics. In this regard, over recent decades, scientists have aimed at developing powerful and safe targeting approaches to restore these suppressive miRNAs in cancerous cells. The present review summarizes the function of miRNAs in tumor development and presents recent findings on how miRNAs have served as therapeutic agents against cancer, with a special focus on tumor suppressor miRNAs (mimics). Moreover, the latest investigations on the therapeutic strategies of miRNA delivery have been presented.

miR‑498 inhibits the growth and metastasis of liver cancer by targeting ZEB2

MicroRNAs (miRNAs) play critical roles in the growth, metastasis and therapeutic resistance of liver cancer. Accumulating evidence suggests that miR-498 is aberrantly expressed in several human malignancies. However, the role and underlying mechanism of miR-498 in liver cancer remain unclear. In the present study, we investigated the potential roles and clinical value of miR-498 in liver cancer. We found that the miR-498 expression level was significantly lower in liver cancer patient tissues than that in healthy control tissues. The expression of miR-498 was also decreased in liver cancer cell lines compared to that noted in a normal human normal liver cell line. miR-498 overexpression markedly inhibited liver cancer cell proliferation, migration and invasion. miR-498 overexpression induced cell cycle arrest and apoptosis while it suppressed epithelial-mesenchymal transition (EMT) in liver cancer cells. Bioinformatic analysis and luciferase reporter assay further identified zinc finger E-box binding homeobox 2 (ZEB2) as a novel target of miR-498. Furthermore, ZEB2 knockdown recapitulated the inhibitory effects of miR-498 overexpression in liver cancer cells. ZEB2 overexpression rescued the inhibition of liver cancer cell proliferation, migration, and invasion by miR-498, indicating that ZEB2 acts as a downstream effector of miR-498 in liver cancer cells. Thus, we demonstrated that miR-498 suppresses the growth and metastasis of liver cancer cells, partly at least, by directly targeting ZEB2, suggesting that miR-498 may serve as a potential biomarker for the diagnosis and therapy of liver cancer.

Upregulating microRNA-498 inhibits gastric cancer proliferation invasion and chemoresistance through inverse interaction of Bmi1

This study aimed to analyze the functions of microRNA 498 (miR-498) on gastric cancer (GC) cell proliferation migration and cisplatin chemosensitivity. QTR-PCR found that miR-498 was markedly downregulated in GC cell lines and human GC tumors. It was discover that, lentivirus-mediated miR-498 overexpression inhibited cancer cell proliferations in vitro and in vivo, invasion and cisplatin chemoresistance. Bmi1 was demonstrated to be directly regulated by miR-498 in GC cell lines. Moreover, Bmi1 upregulation was found to reverse the tumor-suppressing functions of miR-498 in GC. Therefore, this study presented evidence showing miR-498 expression decreased in GC, and overexpressing miR-498 had significant inhibitory effects on GC development, likely through the inverse interaction of Bmi1.

Long non-coding RNA UFC1 promotes gastric cancer progression by regulating miR-498/Lin28b

BACKGROUND

Long non-coding RNAs (lncRNAs) have emerged as important regulators of human cancers. However, the functional roles of lncRNAs and the mechanisms responsible for their aberrant expression in gastric cancer (GC) have not been well characterized.

METHODS

In this study, we examined the expression of lncRNA UFC1 in GC by qRT-PCR and explored its correlation with clinicopathological parameters. In vitro cell functional assays and in vivo animal studies were performed to determine the roles of UFC1 in GC progression.

RESULTS

UFC1 was elevated and predicted poorer prognosis in GC. UFC1 knockdown inhibited while UFC1 overexpression promoted GC cell proliferation, migration, and invasion. UFC1 bound to miR-498 to antagonize its tumor suppressive effect on Lin28b. Suppression of Lin28b by miR-498 could be rescued by UFC1 overexpression, whereas Lin28b overexpression partially rescued UFC1 knockdown-mediated inhibition of GC cell function. Lin28b expression was increased in GC and suggested a co-expression pattern with UFC1.

CONCLUSIONS

UFC1 has a promoting role in GC progression, at least in part, by acting as a miR-498 sponge and derepressing Lin28b expression, which would provide a novel biomarker for GC diagnosis and prognosis and offer a potential target for GC therapy.

Development of Novel Therapeutic Agents by Inhibition of Oncogenic MicroRNAs

MicroRNAs (miRs, miRNAs) are regulatory small noncoding RNAs, with their roles already confirmed to be important for post-transcriptional regulation of gene expression affecting cell physiology and disease development. Upregulation of a cancer-causing miRNA, known as oncogenic miRNA, has been found in many types of cancers and, therefore, represents a potential new class of targets for therapeutic inhibition. Several strategies have been developed in recent years to inhibit oncogenic miRNAs. Among them is a direct approach that targets mature oncogenic miRNA with an antisense sequence known as antimiR, which could be an oligonucleotide or miRNA sponge. In contrast, an indirect approach is to block the biogenesis of miRNA by genome editing using the CRISPR/Cas9 system or a small molecule inhibitor. The development of these inhibitors is straightforward but involves significant scientific and therapeutic challenges that need to be resolved. In this review, we summarize recent relevant studies on the development of miRNA inhibitors against cancer.

MicroRNA-455-3p promotes invasion and migration in triple negative breast cancer by targeting tumor suppressor EI24

Lacking of treatment methods for the patients with triple negative breast cancer (TNBC) underscores the pivotal needs to further understand its biology as well as to find better biomarkers and develop novel therapeutic strategies. Increasing evidences support that aberrantly expressed microRNAs (miRNAs) are involved in tumorigenesis and may serve as biomarkers for diagnostic and prognostic purposes of various cancers. In current study, we found that miR-455-3p and miR-196a-5p were intensively overexpressed in TNBC compared with the hormone receptor (HR) positive breast cancer whereas miR-425-5p was down-regulated by miRNA microarray analysis. qRT-PCR analysis confirmed that the expression of miR-455-3p in TNBC cell lines MDA-MB-231 and MDA-MB-468 was higher than that in HR positive breast cancer cell line MCF-7(p<0.01). Functional experiments in vitro showed that miR-455-3p enhanced cell proliferative, invasive and migrational abilities in TNBC cell lines. miRNA targets prediction showed SMAD2, LTBR and etoposide induced 2.4 (EI24) were potential target genes of miR-455-3p, and then it was confirmed by qRT-PCR assay. Dual luciferase reporter assay showed the specific binding of miR-455-3p to 3′ UTR of EI24 in TNBC. Then we found miR-455-3p inhibited the EI24 expression at the levels of mRNA and protein. Through small interfering RNA (siRNA) targeting EI24 gene, there were strengthened capabilities of invasion and migration of TNBC cells, and increased expression of EI24 had the inverse effects. In conclusion, the data suggest that miRNA455-3p promotes invasion and migration by targeting tumor suppressor EI24 and might be a potential prognostic biomarker and therapeutic target in TNBC.

The potential role of miRNAs in therapy of breast and ovarian cancers associated with BRCA1 mutation

Germline variants within BRCA1 or BRCA2 genes account for approximately 25% of familial aggregations of breast-ovarian cancers. Low or no expression of BRCA1 in breast and ovarian cancers is associated with a good clinical response to treatment with platinum therapies and PARP1 inhibitors. Recent studies demonstrated that microRNAs - small non-coding RNAs, involved in the control of gene expression, can decrease BRCA1 expression by targeting the 3’UTR region of the gene. This article reviews reported relationships between various miRNAs, such as miRNA-9, miRNA-146a, miRNA-182 miRNA-218, miRNA-638 and the response to cytostatic drugs, mainly to platins and PARP1 inhbitors, for the treatment of breast and ovarian cancer associated with BRCA1 mutations.

Metabolism-related microRNAs in maternal breast milk are influenced by premature delivery

BackgroundMaternal breast milk (MBM) is enriched in microRNAs, factors that regulate protein translation throughout the human body. MBM from mothers of term and preterm infants differs in nutrient, hormone, and bioactive-factor composition, but the microRNA differences between these groups have not been compared. We hypothesized that gestational age at delivery influences microRNA in MBM, particularly microRNAs involved in immunologic and metabolic regulation.MethodsMBM from mothers of premature infants (pMBM) obtained 3-4 weeks post delivery was compared with MBM from mothers of term infants obtained at birth (tColostrum) and 3-4 weeks post delivery (tMBM). The microRNA profile in lipid and skim fractions of each sample was evaluated with high-throughput sequencing.ResultsThe expression profiles of nine microRNAs in lipid and skim pMBM differed from those in tMBM. Gene targets of these microRNAs were functionally related to elemental metabolism and lipid biosynthesis. The microRNA profile of tColostrum was also distinct from that of pMBM, but it clustered closely with tMBM. Twenty-one microRNAs correlated with gestational age demonstrated limited relationships with method of delivery, but not other maternal-infant factors.ConclusionPremature delivery results in a unique MBM microRNA profile with metabolic targets. This suggests that preterm milk may have adaptive functions for growth in premature infants.

Deregulation of miR-126-3p in basal-like breast cancers stroma and its clinical significance

INTRODUCTION

The aim of this study was to investigate miR-126-3p expression in stroma and tumor cells of basal-like breast cancer tissues, in an effort to elucidate the potential effect of miR-126-3p on tumor microenvironment and progress of basal-like breast cancer.

METHODS

Expression levels of miR-126-3p in 33 paired basal-like breast cancer tissues were assayed by real-time quantitative PCR. Tumor cells and normal epithelial cell were isolated from ten paired basal-like breast cancer tissues and matched adjacent tissues, separately, using laser capture microdissect(LCM)-based PCR method. Further validated in larger sets were assayed by tissue microarrays (TMA)-based ISH method.

RESULTS

MiR-126-3p expression level had no significant differences between basal-like breast cancer subtypes and matched adjacent tissues. However, a decreasing trend of miR-126-3p expression can be found in tumor cells of basal-like subtype, compared with matched adjacent tissues, using LCM-based PCR. Using TMA method, miR-126-3p expression level was the lowest in stroma of basal-like breast cancers among four subtypes (χ2=10.55, P=0.01), and was increasing in stroma of breast cancers compared with fibroadenomas. Furthermore, strong miR-126-3p expression in stroma is significantly associated with HER-2 expression (χ2=4.70, P=0.03) and Ki-67 index. (χ2=4.84, P=0.03), which suggested a potential prognostic value of miR-126-3p in stroma of breast cancer. However, miR-126-3p expression in tumor cells derived from different subtypes hadn't significant clinical values in this study.

CONCLUSIONS

the miR-126-3p expression level in breast cancer stroma was associated with different intrinsic subtypes and its correlation with hormone receptor and Ki-67 index shed light on the potential clinical prognostic value of miR-126-3p, in the field of specific breast cancer subtypes.

Novel miRNA-mRNA interactions conserved in essential cancer pathways

Cancer is a complex disease in which unrestrained cell proliferation results in tumour development. Extensive research into the molecular mechanisms underlying tumorigenesis has led to the characterization of oncogenes and tumour suppressors that are key elements in cancer growth and progression, as well as that of other important elements like microRNAs. These genes and miRNAs appear to be constitutively deregulated in cancer. To identify signatures of miRNA-mRNA interactions potentially conserved in essential cancer pathways, we have conducted an integrative analysis of transcriptomic data, also taking into account methylation and copy number alterations. We analysed 18,605 raw transcriptome samples from The Cancer Genome Atlas covering 15 of the most common types of human tumours. From this global transcriptome study, we recovered known cancer-associated miRNA-targets and importantly, we identified new potential targets from miRNA families, also analysing the phenotypic outcomes of these genes/mRNAs in terms of survival. Further analyses could lead to novel approaches in cancer therapy.