Pan-cancer characterisation of microRNA across cancer hallmarks reveals microRNA-mediated downregulation of tumour suppressors

LIN28B enhances the chemosensitivity of colon cancer cells via inducing genomic instability by upsetting the balance between the production and removal of reactive oxygen species

Genomic instability is an enabling characteristic that allows cancer cells to acquire additional hallmarks of cancer through the accumulation of alterations in driver genes. Furthermore, it creates opportunities to enhance the sensitivity of cancer cells to chemotherapeutic agents targeting DNA, owing to the presence of incomplete DNA damage repair pathways. This study identifies LIN28B as a crucial regulator of colon cancer cells' sensitivity to DNA damage- or repair-related compounds by promoting genomic instability. LIN28B mechanistically reduces glutathione (GSH) synthesis and activity by inhibiting the expression of four GSH metabolic enzymes (GCLC, G6PD, GSTM4, and GSTT2B), thereby reducing the capacity of cells to eliminate reactive oxygen species (ROS). LIN28B enhances the proinflammatory signaling pathway in cancer cells through the upregulation of ARID3A, a transcription factor that transactivates PTGES and PTGES2, resulting in increased production of PGE2, a key inflammatory mediator that can elevate ROS generation. In conclusion, LIN28B altered the equilibrium of ROS production and elimination in colon cancer, resulting in elevated ROS levels and subsequent genomic instability.

A bioinformatics analysis of the target role of miRNA-431-5p on KLK6 in colorectal cancer

BACKGROUND

Although increasing evidence suggests that microRNAs (miRNAs) play different roles in the occurrence, development, and prognosis of colorectal cancer (CRC), investigations on miRNA-targeted regulation in CRC are sparse. However, the high morbidity and mortality of CRC necessitates exploring this area of research for potential alternative therapeutic approaches to CRC.

METHODS

Bioinformatics analysis was used to obtain the key Hub genes related to CRC, and survival analysis was performed to screen out the core genes. Meanwhile, verification was performed using CCK-8, Transwell, qPCR, WB, immunohistochemistry and dual luciferase assays at a cellular level.

RESULTS

This study identified the hub gene KLK6 associated with CRC based on the GEO and TCGA databases. Survival analysis revealed a significant decrease in the survival rate of CRC patients with increasing expression levels of KLK6. Target gene prediction confirmed that miR-431-5p can target KLK6. Cell experimental results demonstrated that the miR-431-5p inhibitor enhanced cell viability and promoted cell migration and invasion while miR-431-5p mimics reduced cell viability and inhibited cell migration and invasion. Both the inhibitor and mimics of miR-431-5p suppressed and promoted the expression of miR-431-5p, as well as promoted and inhibited the KLK6 mRNA and protein expression. Dual luciferase results showed that miR-431-5p targeted KLK6, and cell recovery experiments further verified that miR-431-5p regulated cell viability, migration and invasion by targeting KLK6.

CONCLUSIONS

Through target gene prediction, miR-431-5p was found to target KLK6, suggesting its therapeutic potential in CRC. As such, therapies that can inhibit KLK6 via miR-431-5p offer a promising approach to CRC.

CLINICAL TRIAL NUMBER

Not applicable.

Ligation-recognition triggered RPA-Cas12a cis-cleavage fluorogenic RNA aptamer for one-pot and label-free detection of MicroRNA in breast cancer

"One-pot" assays which combine amplification with CRISPR/Cas12a system are in constant attracted for biosensors development. Herein, we present a one-pot isothermal assay that Ligation-recognition triggered Recombinase Polymerase Amplification (RPA)-CRISPR/Cas12a cis-cleavage (LRPA-CRISPR) fluorescent biosensor for sensitive, specific, and label-free miRNA detection. Firstly, we reveal the programmed double-stranded DNA amplicons, which utilized the ligation-recognition and polymerization to form and amplified by the RPA system. Meanwhile, we enabled exponential ligation-recognition triggered recombinase polymerase amplification of miRNA-21 sequences and exploited the cis-cleavage mechanism of Cas12a with transcription to generate functional Mango RNA for signal output. This assay can be completed within 40 min and can allow a limit of detection of 3.43 aM for miRNA-21 detection, owing to the RPA with transcription amplification and enables to product the functional Mango RNA aptamer by in vitro transcription that binds to the TO1-Biotin fluorogenic dye. Moreover, our method exhibits the advantages of self-supply crRNA, label-free, excellent specificity, and universal detection platform via the design of one-pot detection in serum and cell samples, showing tremendous potential in biomarkers diagnostics of breast cancer.

Regulation of KIF23 by miR-107 controls replicative tumor cell fitness in mouse and human hepatocellular carcinoma

BACKGROUND & AIMS

In hepatocellular carcinoma (HCC), successful translation of experimental targets identified in mouse models to human patients has proven challenging. In this study, we used a comprehensive transcriptomic approach in mice to identify novel potential targets for therapeutic intervention in humans.

METHODS

We analyzed combined genome-wide miRNA and mRNA expression data in three pathogenically distinct mouse models of liver cancer. Effects of target genes on hepatoma cell fitness were evaluated by proliferation, survival and motility assays. TCGA and GEO databases, in combination with tissue microarrays, were used to validate the mouse targets and their impact on human HCC prognosis. Finally, the functional effects of the identified targets on tumorigenesis and tumor therapy were tested in hydrodynamic tail vein injection-based preclinical HCC models in vivo.

RESULTS

The expression of miR-107 was found to be significantly reduced in mouse models of liver tumors of various etiologies and in cohorts of humans with HCC. Overexpression of miR-107 or inhibition of its novel target kinesin family member 23 (Kif23) significantly reduced proliferation by interfering with cytokinesis, thereby controlling survival and motility of mouse and human hepatoma cells. In humans, KIF23 expression was found to be a prognostic marker in liver cancer, with high expression associated with poor prognosis. Hydrodynamic tail vein injection of vectors carrying either pre-miR-107 or anti-Kif23 shRNA inhibited the development of highly aggressive c-Myc-NRAS-induced liver cancers in mice.

CONCLUSIONS

Disruption of the miR-107/Kif23 axis inhibited hepatoma cell proliferation in vitro and prevented oncogene-induced liver cancer development in vivo, offering a novel potential avenue for the treatment of HCC in humans.

IMPACT AND IMPLICATIONS

Our study revealed the central role of the miR-107/KIF23 axis in controlling tumor cell fitness and hepatocellular carcinoma progression. The results demonstrate that the overexpression of miR-107 or silencing of its target, KIF23, markedly suppresses the proliferation, survival, and motility of human and mouse hepatoma cells. In this work, we demonstrate that the disruption of miR-107/Kif23 signaling effectively protects mice from an aggressive form of oncogene-induced liver cancer in vivo, implying that targeting miR-107/KIF23 might be a novel therapeutic approach for hepatocellular carcinoma in humans.

Harnessing DNA computing and nanopore decoding for practical applications: from informatics to microRNA-targeting diagnostics

DNA computing represents a subfield of molecular computing with the potential to become a significant area of next-generation computation due to the high programmability inherent in the sequence-dependent molecular behaviour of DNA. Recent studies in DNA computing have extended from mathematical informatics to biomedical applications, with a particular focus on diagnostics that exploit the biocompatibility of DNA molecules. The output of DNA computing devices is encoded in nucleic acid molecules, which must then be decoded into human-recognizable signals for practical applications. Nanopore technology, which utilizes an electrical and label-free decoding approach, provides a unique platform to bridge DNA and electronic computing for practical use. In this tutorial review, we summarise the fundamental knowledge, technologies, and methodologies of DNA computing (logic gates, circuits, neural networks, and non-DNA input circuity). We then focus on nanopore-based decoding, and highlight recent advances in medical diagnostics targeting microRNAs as biomarkers. Finally, we conclude with the potential and challenges for the practical implementation of these techniques. We hope that this tutorial will provide a comprehensive insight and enable the general reader to grasp the fundamental principles and diverse applications of DNA computing and nanopore decoding, and will inspire a wide range of scientists to explore and push the boundaries of these technologies.

The lncRNA and miRNA regulatory axis in HPV16-positive oropharyngeal cancers

The global rise of oropharyngeal cancers (OPC) associated with the human papillomavirus (HPV) type 16 necessitates a deeper understanding of their underlying molecular mechanisms. Our study utilised RNA-sequencing data from The Cancer Genome Atlas (TCGA) to identify and analyse differentially expressed (DE) long non-coding RNAs (lncRNAs), microRNAs (miRNAs), and messenger RNAs (mRNAs) in HPV16-positive OPC, and to elucidate the interplay within the lncRNA/miRNA/mRNA regulatory network. We revealed 1929 DE lncRNAs and identified a significant expression shift in 37 of these, suggesting a regulatory 'sponge' function for miRNAs that modulate cellular processes. Notably, the lncRNA Linc00911 exhibited decreased expression in HPV16-positive OPC, a change directly attributable to HPV oncogenes E6 and E7 as confirmed by RT-qPCR in cell lines and patient samples. Our comprehensive analysis presents an expansive landscape of ncRNA-mRNA interactions, offering a resource for the ongoing pursuit of elucidating the molecular underpinnings of HPV-driven OPC.

Triclosan impairs spermatocyte cell proliferation and induces autophagy by regulating microRNA-20a-5 P by pargeting PTEN

BACKGROUND

Triclosan (TCS), as an endocrine disrupter, has been found to affect male fertility. However, the potential molecular mechanism is still unknown. We aimed to investigate whether the toxic effects of TCS on spermatocyte cells was mediated by the regulation of microRNA-20a-5 P on PTEN.

METHODS

GC-2 and TM4 cells were treated with TCS (0.5-80 μM) for 24 or 48 hours. Effect of TCS on proliferation of GC-2 and TM4 cells was detected using a cell counting kit-8 (CCK8) assay. Expression of miR-17 family and autophagy genes were detected. The interaction between miR-20a-5 P and PTEN was determined by a dual-luciferase reporter assay.

RESULTS

TCS decreased cell proliferation of GC-2 and TM4 cells. Expression of autophagy-related genes and miR-17 family was altered by TCS. PTEN expression was significantly increased, whereas the expression of miR-20a-5 P was significantly decreased in GC-2 and TM4 cells. As predicted in relevant databases, there is a binding site of miR-20a-5 P in PTEN. The expression of PTEN was significantly down-regulated by the miR-20a-5 P mimic.

CONCLUSION

As a downstream target of miR-20a-5 P, PTEN functioned in the autophagy process of which TCS inhibited the proliferation of spermatocyte cells. Our results provided new ideas for revealing the molecular mechanism and protective strategy on male infertility.

Identification of miRNA signature in cancer-associated fibroblast to predict recurrent prostate cancer

BACKGROUND

Cancer-associated fibroblasts (CAFs) are one of the major components of prostate stromal cells, which play a crucial part in tumor development and treatment resistance. This study aimed to establish a model of CAFs-related microRNAs (miRNAs) to assess prognostic differences, tumor microenvironments, and screening of anticancer drugs by integrating data from single-cell RNA sequencing (scRNA-seq) and bulk RNA sequencing (buRNA-seq).

METHODS

scRNA-seq and buRNA-seq data of primary prostate cancer (PCa) were downloaded from Gene Expression Omnibus and The Cancer Genome Atlas databases. Statistical methods including Least absolute shrinkage and selection operator (Lasso), Lasso penalized, Random Forest, Random Forest Combination, and Support Vector Machine (SVM) were performed to select hub miRNAs. Pathway analyses and assessment of infiltrating immune cells were conducted using Gene Set Enrichment Analysis and the CIBERSORT algorithm. The expression of CAFs-related miRNAs in fibroblast cell lines were validated through quantitative real-time PCR. Cell Counting Kit 8 (CCK8), wound-healing, clone formation, and cell migration assays were used to explore cell proliferation, growth, and migration in vitro. A mouse xenograft model was established to investigate the effect of CAFs on tumor growth in vivo.

RESULTS

Through single-cell transcriptomics analysis in 34 PCa patients, 89 CAFs-related mRNAs were identified. A prognostic model based on 9 CAFs-related miRNAs (hsa-miR-1258, hsa-miR-133b, hsa-miR-222-3p, hsa-miR-145-3p, hsa-miR-493-5p, hsa-miR-96-5p, hsa-miR-15b-5p, hsa-miR-106b-5p, and hsa-miR-191-5p) was established to predict biochemical recurrence (BCR). We have determined through two prediction methods that NVP-TAE684 may be the optimal targeted therapy drug for treating CAFs. Downregulation of hsa-miR-106b-5p in CAFs significantly suppressed cell proliferation, migration, and colony formation in vitro. In vivo studies using a xenograft model further confirmed that hsa-miR-106b-5p downregulation significantly reduced tumor growth.

CONCLUSION

Our findings conducted an integrated bioinformatic analysis to develop a CAFs-related miRNAs model that provides prognostic insights into individualized and precise treatment for prostate adenocarcinoma patients. Downregulation of miR-106b-5p in CAFs significantly suppressed tumor growth, suggesting a potential therapeutic target for cancer treatment.

Evaluating the Urinary Exosome microRNA Profile of von Hippel Lindau Syndrome Patients with Clear Cell Renal Cell Carcinoma

INTRODUCTION

Renal cell carcinoma is one of the ten more common malignant tumors worldwide, with a high incidence and mortality rate. Kidney cancer frequently presents at an advanced stage, and it is almost invariably fatal. Much progress has been made in identifying molecular targets for therapy in the hope of improving survival rates, but still, we have no good markers for early detection or progression of the disease. Von Hippel Lindau syndrome (VHL) is an autosomal dominant cancer hereditary syndrome in which affected individuals are at risk of developing bilateral and multifocal renal cell carcinomas (RCC) as well as other tumors. These patients provide an ideal platform to investigate the potential of urinary exosomal miRNA biomarkers in the early development of ccRCC, as these patients are regularly imaged and tumors are actively monitored until the tumor reaches 3 cm before surgical excision. This allows for pre- and post-surgical urine collection and comparison to excised tumor tissues. Studying different biomarkers in urine can provide comprehensive molecular profiling available to patients and physicians and can be a great source of additional tumor genetic information.

METHODS

Pre- and postoperative urine samples were obtained from a cohort of VHL patients undergoing surveillance and surgical excision of ccRCCs, and exosomes were extracted. MicroRNA-Seq analysis was performed on miRNA extracted from both urine-derived exosomes and FFPE material from excised ccRCCs.

RESULTS

MicroRNA-Seq analysis highlighted a significant difference in the urinary exosome-derived miRNA expression profiles between VHL patients and normal control individuals. This included decreased expression of the miR-320 family, such as miR-320a, known to be decreased in sporadic ccRCC and suppressed by the HIF1α transcription factor activated by the loss of the VHL gene. MiR-542-5p represented a potential marker of VHL-associated ccRCC that was lowly expressed in normal control urinary exosomes, significantly increased in the preoperative urinary exosomes of tumor-bearing VHL patients, and subsequently reduced to normal levels of expression after tumor excision. In concordance with this, the expression of miR-542-5p was increased in the VHL-associated ccRCC in comparison to the normal kidney.

CONCLUSIONS

This study shows the potential for miRNA profiling of exosomes from readily available biofluids to both distinguish VHL patient urine from normal control urine microRNAs and to provide biomarkers for the presence of VHL syndrome-associated ccRCC. Further validation studies are necessary to demonstrate the utility of urinary exosome-derived miRNAs as biomarkers in kidney cancer.

Thrombomodulin: a multifunctional receptor modulating the endothelial quiescence

Thrombomodulin (TM) is a type 1 receptor best known for its function as an anticoagulant cofactor for thrombin activation of protein C on the surface of vascular endothelial cells. In addition to its anticoagulant cofactor function, TM also regulates fibrinolysis, complement, and inflammatory pathways. TM is a multidomain receptor protein with a lectin-like domain at its N-terminus that has been shown to exhibit direct anti-inflammatory functions. This domain is followed by 6 epidermal growth factor-like domains that support the interaction of TM with thrombin. The interaction inhibits the procoagulant function of thrombin and enables the protease to regulate the anticoagulant and fibrinolytic pathways by activating protein C and thrombin-activatable fibrinolysis inhibitor. TM has a Thr/Ser-rich region immediately above the membrane surface that harbors chondroitin sulfate glycosaminoglycans, and this region is followed by a single-spanning transmembrane and a C-terminal cytoplasmic domain. The structure and physiological function of the extracellular domains of TM have been extensively studied, and numerous excellent review articles have been published. However, the physiological function of the cytoplasmic domain of TM has remained poorly understood. Recent data from our laboratory suggest that intracellular signaling by the cytoplasmic domain of TM plays key roles in maintaining quiescence by modulating phosphatase and tensin homolog signaling in endothelial cells. This article briefly reviews the structure and function of extracellular domains of TM and focuses on the mechanism and possible physiological importance of the cytoplasmic domain of TM in modulating phosphatase and tensin homolog signaling in endothelial cells.

miR-644a is a tumor cell-intrinsic mediator of sex bias in glioblastoma

Background

Biological sex is an important risk factor for glioblastoma (GBM), with males having a higher incidence and poorer prognosis. The mechanisms for this sex bias are thought to be both tumor intrinsic and tumor extrinsic. MicroRNAs (miRNAs), key post-transcriptional regulators of gene expression, have been previously linked to sex differences in various cell types and diseases, but their role in the sex bias of GBM remains unknown.

Methods

We leveraged previously published paired miRNA and mRNA sequencing of 39 GBM patients (22 male, 17 female) to identify sex-biased miRNAs. We further interrogated a separate single-cell RNA sequencing dataset of 110 GBM patients to examine whether differences in miRNA target gene expression were tumor cell intrinsic or tumor cell extrinsic. Results were validated in a panel of patient-derived cell models.

Results

We identified 10 sex-biased miRNAs (adjusted < 0.1), of which 3 were more highly expressed in males and 7 more highly expressed in females. Of these, miR-644a was higher in females, and increased expression of miR-644a target genes was significantly associated with decreased overall survival (HR 1.3, p = 0.02). Furthermore, analysis of an independent single-cell RNA sequencing dataset confirmed sex-specific expression of miR-644a target genes in tumor cells (p < 10-15). Among patient derived models, miR-644a was expressed a median of 4.8-fold higher in females compared to males.

Conclusions

Our findings implicate miR-644a as a candidate tumor cell-intrinsic regulator of sex-biased gene expression in GBM.

Non-coding RNAs in disease: from mechanisms to therapeutics

Non-coding RNAs (ncRNAs) are a heterogeneous group of transcripts that, by definition, are not translated into proteins. Since their discovery, ncRNAs have emerged as important regulators of multiple biological functions across a range of cell types and tissues, and their dysregulation has been implicated in disease. Notably, much research has focused on the link between microRNAs (miRNAs) and human cancers, although other ncRNAs, such as long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), are also emerging as relevant contributors to human disease. In this Review, we summarize our current understanding of the roles of miRNAs, lncRNAs and circRNAs in cancer and other major human diseases, notably cardiovascular, neurological and infectious diseases. Further, we discuss the potential use of ncRNAs as biomarkers of disease and as therapeutic targets.

CMC: Cancer miRNA Census - a list of cancer-related miRNA genes

A growing body of evidence indicates an important role of miRNAs in cancer; however, there is no definitive, convenient-to-use list of cancer-related miRNAs or miRNA genes that may serve as a reference for analyses of miRNAs in cancer. To this end, we created a list of 165 cancer-related miRNA genes called the Cancer miRNA Census (CMC). The list is based on a score, built on various types of functional and genetic evidence for the role of particular miRNAs in cancer, e.g. miRNA-cancer associations reported in databases, associations of miRNAs with cancer hallmarks, or signals of positive selection of genetic alterations in cancer. The presence of well-recognized cancer-related miRNA genes, such as MIR21, MIR155, MIR15A, MIR17 or MIRLET7s, at the top of the CMC ranking directly confirms the accuracy and robustness of the list. Additionally, to verify and indicate the reliability of CMC, we performed a validation of criteria used to build CMC, comparison of CMC with various cancer data (publications and databases), and enrichment analyses of biological pathways and processes such as Gene Ontology or DisGeNET. All validation steps showed a strong association of CMC with cancer/cancer-related processes confirming its usefulness as a reference list of miRNA genes associated with cancer.

A large-scale microRNA transcriptome-wide association study identifies two susceptibility microRNAs, miR-1307-5p and miR-192-3p, for colorectal cancer risk

Transcriptome-wide association studies (TWAS) have identified many putative susceptibility genes for colorectal cancer (CRC) risk. However, susceptibility miRNAs, critical dysregulators of gene expression, remain unexplored. We genotyped DNA samples from 313 CRC East Asian patients and performed small RNA sequencing in their normal colon tissues distant from tumors to build genetic models for predicting miRNA expression. We applied these models and data from genome-wide association studies (GWAS) including 23 942 cases and 217 267 controls of East Asian ancestry to investigate associations of predicted miRNA expression with CRC risk. Perturbation experiments separately by promoting and inhibiting miRNAs expressions and further in vitro assays in both SW480 and HCT116 cells were conducted. At a Bonferroni-corrected threshold of P < 4.5 × 10-4, we identified two putative susceptibility miRNAs, miR-1307-5p and miR-192-3p, located in regions more than 500 kb away from any GWAS-identified risk variants in CRC. We observed that a high predicted expression of miR-1307-5p was associated with increased CRC risk, while a low predicted expression of miR-192-3p was associated with increased CRC risk. Our experimental results further provide strong evidence of their susceptible roles by showing that miR-1307-5p and miR-192-3p play a regulatory role, respectively, in promoting and inhibiting CRC cell proliferation, migration, and invasion, which was consistently observed in both SW480 and HCT116 cells. Our study provides additional insights into the biological mechanisms underlying CRC development.

The regulatory mechanisms of oncomiRs in cancer

Cancer development is a complex process that primarily results from the combination of genetic alterations and the dysregulation of major signalling pathways due to interference with the epigenetic machinery. As major epigenetic regulators, miRNAs are central players in the control of many key tumour development factors. These miRNAs have been classified as oncogenic miRNAs (oncomiRs) when they target tumour suppressor genes and tumour suppressor miRNAs (TS miRNAs) when they inhibit oncogene protein expression. Most of the mechanisms that modulate oncomiR expression are linked to transcriptional or posttranscriptional regulation. However, non-transcriptional processes, such as gene amplification, have been described as alternative processes that are responsible for increasing oncomiR expression. The current review summarises the different mechanisms controlling the upregulation of oncomiR expression in cancer cells and the tumour microenvironment (TME). Detailed knowledge of the mechanism underlying the regulation of oncomiR expression in cancer may pave the way for understanding the critical role of oncomiRs in cancer development and progression.

Self-Priming Cyclic Amplification Accelerating CRISPR Sensor for Sensitive and Specific MicroRNA Analysis with No Background

In this work, we demonstrate for the first time the application of the phosphorothioated-terminal hairpin formation and self-priming extension (PS-THSP) reaction for miRNA assays. A self-priming amplification accelerating CRISPR sensor was well-established for sensitive and specific miRNA detection by integrating the PS-THSP reaction and CRISPR/Cas12a system. The sensor consists of three steps: (1) the formation of a complete PS-THSP template in the presence of target miRNA and ligase; (2) the exponential isothermal amplification of the PS-THSP reaction under the action of DNA polymerase; (3) the activation of the CRISPR/Cas12a fluorescence system to generate signals. We used miR-21 as a model target. The sensor can achieve sensitive detection of miR-21 without the involvement of any primers, and the special design of the CRISPR proto-spacer neighbor motif (PAM) sequence effectively avoids the interference of the background signal. In addition, the sensor can not only identify single-base mutant homologous sequences but also show stable performance in complex biological matrices. We have successfully used this sensor to accurately analyze miR-21 in different cell lines and real clinical samples, demonstrating its great potential in clinical diagnosis.

miR-644a is a tumor cell-intrinsic mediator of sex bias in glioblastoma

Background

Biological sex is an important risk factor for glioblastoma (GBM), with males having a higher incidence and poorer prognosis. The mechanisms for this sex bias are thought to be both tumor intrinsic and tumor extrinsic. MicroRNAs (miRNAs), key posttranscriptional regulators of gene expression, have been previously linked to sex differences in various cell types and diseases, but their role in the sex bias of GBM remains unknown.

Methods

We leveraged previously published paired miRNA and mRNA sequencing of 39 GBM patients (22 male, 17 female) to identify sex-biased miRNAs. We further interrogated a separate single-cell RNA-sequencing dataset of 110 GBM patients to examine whether differences in miRNA target gene expression were tumor cell-intrinsic or tumor cell extrinsic. Results were validated in a panel of patient-derived cell models.

Results

We identified 10 sex-biased miRNAs (p adjusted < .1), of which 3 were more highly expressed in males and 7 more highly expressed in females. Of these, miR-644a was higher in females, and increased expression of miR-644a target genes was significantly associated with decreased overall survival (HR 1.3, P = .02). Furthermore, analysis of an independent single-cell RNA-sequencing dataset confirmed sex-specific expression of miR-644a target genes in tumor cells (P < 10-15). Among patient-derived models, miR-644a was expressed a median of 4.8-fold higher in females compared to males.

Conclusions

Our findings implicate miR-644a as a candidate tumor cell-intrinsic regulator of sex-biased gene expression in GBM.

Intraoperative radiotherapy in breast cancer: Alterations to the tumor microenvironment and subsequent biological outcomes (Review)

Intraoperative radiotherapy (IORT) is a precise, single high‑dose irradiation directly targeting the tumor bed during surgery. In comparison with traditional external beam RT, it minimizes damage to other normal tissues, ensures an adequate dose to the tumor bed and results in improved cosmetic outcomes and quality of life. Furthermore, IORT offers a shorter treatment duration, lower economic costs and therapeutic efficacy comparable with traditional RT. However, its relatively higher local recurrence rate limits its further clinical applications. Identifying effective radiosensitizing drugs and rational RT protocols will improve its advantages. Furthermore, IORT may not only damage DNA to directly kill breast tumor cells but also alter the tumor microenvironment (TME) to exert a sustained antitumor effect. Specific doses of IORT may exert anti‑angiogenic effects, and consequently antitumor effects, by impacting post‑radiation peripheral blood levels of vascular endothelial growth factor and delta‑like 4. IORT may also modify the postoperative wound fluid composition to continuously inhibit tumor growth, e.g. by reducing components such as microRNA (miR)‑21, miR‑221, miR‑115, oncostatin M, TNF‑β, IL‑6 and IL‑8, and by elevating levels of components such as miR‑223, to inhibit the ability of postoperative wound fluid to induce proliferation, invasion and migration of residual cancer cells. IORT can also modify cancer cell glucose metabolism to inhibit the proliferation of residual tumor cells. In addition, IORT can induce a bystander effect, eliminating the postoperative wound fluid‑induced epithelial‑mesenchymal transition and tumor stem cell phenotype. Insights gained at the molecular level may provide new directions for identifying novel therapeutic targets and approaches. A more comprehensive understanding of the effects of IORT on the breast cancer (BC) TME may further its clinical application. Hence, the present article reviews the primary effects of IORT on BC and its impact on the TME, aiming to offer fresh research perspectives for relevant professionals.

Targeting histone deacetylase suppresses tumor growth through eliciting METTL14-modified m6 A RNA methylation in ocular melanoma

BACKGROUND

Diversified histone deacetylation inhibitors (HDACis) have demonstrated encouraging outcomes in multiple malignancies. N6-methyladenine (m6 A) is the most prevalent messenger RNA modification that plays an essential role in the regulation of tumorigenesis. Howbeit, an in-depth understanding of the crosstalk between histone acetylation and m6 A RNA modifications remains enigmatic. This study aimed to explore the role of histone acetylation and m6 A modifications in the regulation of tumorigenesis of ocular melanoma.

METHODS

Histone modification inhibitor screening was used to explore the effects of HDACis on ocular melanoma cells. Dot blot assay was used to detect the global m6 A RNA modification level. Multi-omics assays, including RNA-sequencing, cleavage under targets and tagmentation, single-cell sequencing, methylated RNA immunoprecipitation-sequencing (meRIP-seq), and m6 A individual nucleotide resolution cross-linking and immunoprecipitation-sequencing (miCLIP-seq), were performed to reveal the mechanisms of HDACis on methyltransferase-like 14 (METTL14) and FAT tumor suppressor homolog 4 (FAT4) in ocular melanoma. Quantitative real-time polymerase chain reaction (qPCR), western blotting, and immunofluorescent staining were applied to detect the expression of METTL14 and FAT4 in ocular melanoma cells and tissues. Cell models and orthotopic xenograft models were established to determine the roles of METTL14 and FAT4 in the growth of ocular melanoma. RNA-binding protein immunoprecipitation-qPCR, meRIP-seq, miCLIP-seq, and RNA stability assay were adopted to investigate the mechanism by which m6 A levels of FAT4 were affected.

RESULTS

First, we found that ocular melanoma cells presented vulnerability towards HDACis. HDACis triggered the elevation of m6 A RNA modification in ocular melanoma. Further studies revealed that METTL14 served as a downstream candidate for HDACis. METTL14 was silenced by the hypo-histone acetylation status, whereas HDACi restored the normal histone acetylation level of METTL14, thereby inducing its expression. Subsequently, METTL14 served as a tumor suppressor by promoting the expression of FAT4, a tumor suppressor, in a m6 A-YTH N6-methyladenosine RNA-binding protein 1-dependent manner. Taken together, we found that HDACi restored the histone acetylation level of METTL14 and subsequently elicited METTL14-mediated m6 A modification in tumorigenesis.

CONCLUSIONS

These results demonstrate that HDACis exert anti-cancer effects by orchestrating m6 A modification, which unveiling a "histone-RNA crosstalk" of the HDAC/METTL14/FAT4 epigenetic cascade in ocular melanoma.

Low-Background CRISPR/Cas12a Sensors for Versatile Live-Cell Biosensing

The trans-cleavage activity of CRISPR/Cas12a has been widely used in biosensing. However, many CRISPR/Cas12a-based biosensors, especially those that work in "on-off-on" mode, usually suffer from high background and thus impossible intracellular application. Herein, this problem is efficiently overcome by elaborately designing the activator strand (AS) of CRISPR/Cas12a using the "RESET" effect found by our group. The activation ability of the as-designed AS to CRISPR/Cas12a can be easily inhibited, thus assuring a low background for subsequent biosensing applications, which not only benefits the detection sensitivity improvement of CRISPR/Cas12a-based biosensors but also promotes their applications in live cells as well as makes it possible to design high-performance biosensors with greatly improved flexibility, thus achieving the analysis of a wide range of targets. As examples, by using different strategies such as strand displacement, strand cleavage, and aptamer-substrate interaction to reactivate the inhibited enzyme activity, several CRISPR/Cas12a-based biosensing systems are developed for the sensitive and specific detection of different targets, including nucleic acid (miR-21), biological small molecules (ATP), and enzymes (hOGG1), giving the detection limits of 0.96 pM, 8.6 μM, and 8.3 × 10-5 U/mL, respectively. Thanks to the low background, these biosensors are demonstrated to work well for the accurate imaging analysis of different biomolecules in live cells. Moreover, we also demonstrate that these sensing systems can be easily combined with lateral flow assay (LFA), thus holding great potential in point-of-care testing, especially in poorly equipped or nonlaboratory environments.

Unraveling the Possibilities: Recent Progress in DNA Biosensing

Due to the advantages of its numerous modification sites, predictable structure, high thermal stability, and excellent biocompatibility, DNA is the ideal choice as a key component of biosensors. DNA biosensors offer significant advantages over existing bioanalytical techniques, addressing limitations in sensitivity, selectivity, and limit of detection. Consequently, they have attracted significant attention from researchers worldwide. Here, we exemplify four foundational categories of functional nucleic acids: aptamers, DNAzymes, i-motifs, and G-quadruplexes, from the perspective of the structure-driven functionality in constructing DNA biosensors. Furthermore, we provide a concise overview of the design and detection mechanisms employed in these DNA biosensors. Noteworthy advantages of DNA as a sensor component, including its programmable structure, reaction predictility, exceptional specificity, excellent sensitivity, and thermal stability, are highlighted. These characteristics contribute to the efficacy and reliability of DNA biosensors. Despite their great potential, challenges remain for the successful application of DNA biosensors, spanning storage and detection conditions, as well as associated costs. To overcome these limitations, we propose potential strategies that can be implemented to solve these issues. By offering these insights, we aim to inspire subsequent researchers in related fields.

miRNome expression analysis in canine diffuse large B-cell lymphoma

Introduction

Lymphoma is a common canine cancer with translational relevance to human disease. Diffuse large B-cell lymphoma (DLBCL) is the most frequent subtype, contributing to almost fifty percent of clinically recognized lymphoma cases. Identifying new biomarkers capable of early diagnosis and monitoring DLBCL is crucial for enhancing remission rates. This research seeks to advance our knowledge of the molecular biology of DLBCL by analyzing the expression of microRNAs, which regulate gene expression by negatively impacting gene expression via targeted RNA degradation or translational repression. The stability and accessibility of microRNAs make them appropriate biomarkers for the diagnosis, prognosis, and monitoring of diseases.

Methods

We extracted and sequenced microRNAs from ten fresh-frozen lymph node tissue samples (six DLBCL and four non-neoplastic).

Results

Small RNA sequencing data analysis revealed 35 differently expressed miRNAs (DEMs) compared to controls. RT-qPCR confirmed that 23/35 DEMs in DLBCL were significantly upregulated (n = 14) or downregulated (n = 9). Statistical significance was determined by comparing each miRNA's average expression fold-change (2-Cq) between the DLCBL and healthy groups by applying the unpaired parametric Welch's 2-sample t-test and false discovery rate (FDR). The predicted target genes of the DEMs were mainly enriched in the PI3K-Akt-MAPK pathway.

Discussion

Our data point to the potential value of miRNA signatures as diagnostic biomarkers and serve as a guideline for subsequent experimental studies to determine the targets and functions of these altered miRNAs in canine DLBCL.

CDK4/6 inhibitors and the pRB-E2F1 axis suppress PVR and PD-L1 expression in triple-negative breast cancer

Immune-checkpoint (IC) modulators like the poliovirus receptor (PVR) and programmed death ligand 1 (PD-L1) attenuate innate and adaptive immune responses and are potential therapeutic targets for diverse malignancies, including triple-negative breast cancer (TNBC). The retinoblastoma tumor suppressor, pRB, controls cell growth through E2F1-3 transcription factors, and its inactivation drives metastatic cancer, yet its effect on IC modulators is contentious. Here, we show that RB-loss and high E2F1/E2F2 signatures correlate with expression of PVR, CD274 (PD-L1 gene) and other IC modulators and that pRB represses whereas RB depletion and E2F1 induce PVR and CD274 in TNBC cells. Accordingly, the CDK4/6 inhibitor, palbociclib, suppresses both PVR and PD-L1 expression. Palbociclib also counteracts the effect of CDK4 on SPOP, leading to its depletion, but the overall effect of palbociclib is a net reduction in PD-L1 level. Hydrochloric acid, commonly used to solubilize palbociclib, counteracts its effect and induces PD-L1 expression. Remarkably, lactic acid, a by-product of glycolysis, also induces PD-L1 as well as PVR. Our results suggest a model in which CDK4/6 regulates PD-L1 turnover by promoting its transcription via pRB-E2F1 and degradation via SPOP and that the CDK4/6-pRB-E2F pathway couples cell proliferation with the induction of multiple innate and adaptive immunomodulators, with direct implications for cancer progression, anti-CDK4/6- and IC-therapies.

Expression Patterns of microRNAs and Associated Target Genes in Ulcerated Primary Cutaneous Melanoma

Ulcerated cutaneous melanoma carries a poor prognosis, and the underlying biology driving its aggressive behavior is largely unexplored. MicroRNAs (miRs) are small, noncoding RNAs that inhibit the expression of specific genes and exhibit dysregulated expression patterns in cancer. We hypothesized that a unique miR profile exists in ulcerated relative to nonulcerated melanoma and that miR expression inversely correlates with target genes of biologic importance. Expression of miRs and mRNAs was assessed in ulcerated and nonulcerated cutaneous melanomas using the NanoString Human miRNA and Tumor Signaling 360 mRNA assays and validated in an independent cohort. Pathway enrichment and functional annotations for differentially expressed miRs and mRNAs were determined using publicly available databases. Pearson correlations were employed to predict potential miR‒mRNA binding pairs. Ulcerated melanoma tissue showed at least 1.5-fold change in relative expression of 24 miRs, including miR-206, miR-1-3p, and miR-4286 (>2.25-fold decrease, P < 0.048) and miR-146a-5p, miR-196b-5p, and miR-363-3p (>2.5-fold increase, P < 0.014). Ulcerated melanomas also had 21 differentially expressed mRNAs relative to nonulcerated tumors (P < 0.01), among which two had an inverse correlation in expression with regulatory miRs (SOCS3 and miR-218-5p and IL7R and miR-376c-5p). This miR expression profile adds to the molecular characterization of the poorly understood histopathologic phenotype of ulcerated melanoma.

MiR-144/451a cluster synergistically modulates growth and metastasis of Oral Carcinoma

OBJECTIVES

MicroRNA (miRNA) clusters co-transcribe and function in a coordinated fashion mediating synergistic or antagonistic regulatory effects. MiR-144 and miR-451a are deregulated in various cancers but the combined regulatory role of miR-144/451a cluster in oral squamous cell carcinoma (OSCC) remains unexplored. In the present study, we studied the synergistic effect of miR-144/451a cluster on oral cancer progression.

MATERIALS AND METHODS

miR-144 and miR-451a expression was explored in OSCC cell lines by quantitative real-time PCR (qRT-PCR). Proliferation, wound healing, migration and invasion, spheroid formation, and colony formation assays were performed after transfection with miR-144-3p, miR-451a, miR-144-5p, and co-expressed miR-144/451a. Expression of putative target genes was analyzed using qRT-PCR and Western blotting.

RESULTS

miR-144 and miR-451a were downregulated in all cell lines. The cell viability and stemness of cancer cell lines were unaltered when treated with miRNA mimics. However, co-expressed miR-144/451a significantly reduced the migratory, invasive, and clonogenic potential of cells than individual miRNAs.

CONCLUSION

miR-144/451a cluster functions as a tumor suppressor in OSCC by inhibiting cancer cell invasion, migration, and clonogenic potential.

An miRNA Signature Predicts Grading of Pancreatic Neuroendocrine Neoplasms

BACKGROUND/AIM

Grading pancreatic neuroendocrine neoplasms (PNENs) via mitotic rate and Ki-67 index score is complicated by interobserver variability. Differentially expressed miRNAs (DEMs) are useful for predicting tumour progression and may be useful for grading.

PATIENTS AND METHODS

Twelve PNENs were selected. Four patients had grade (G) 1 pancreatic neuroendocrine tumours (PNETs); 4 had G2 PNETs; and 4 had G3 PNENs (2 PNETs and 2 pancreatic neuroendocrine carcinomas). Samples were profiled using the miRNA NanoString Assay.

RESULTS

There were 6 statistically significant DEMs between different grades of PNENs. MiR1285-5p was the sole miRNA differentially expressed (p=0.03) between G1 and G2 PNETs. Six statistically significant DEMs (miR135a-5p, miR200a-3p, miR3151-5p, miR-345-5p, miR548d-5p and miR9-5p) (p<0.05) were identified between G1 PNETs and G3 PNENs. Finally, 5 DEMs (miR155-5p, miR15b-5p, miR222-3p, miR548d-5p and miR9-5p) (p<0.05) were identified between G2 PNETs and G3 PNENs.

CONCLUSION

The identified miRNA candidates are concordant with their patterns of dysregulation in other tumour types. The reliability of these DEMs as discriminators of PNEN grades support further investigations using larger patient populations.

Control of focal adhesion kinase activation by RUNX1-regulated miRNAs in high-risk AML

We recently described a 16-gene expression signature for improved risk stratification of acute myeloid leukemia (AML) patients called the AML Prognostic Score (APS). A subset of APS-high-risk AML patients showed increased levels of focal adhesion kinase (FAK), encoded by the Protein Tyrosine Kinase 2 (PTK2) gene, which was correlated with RUNX1 mutations. RUNX1 mutant cells are more sensitive to PTK2 inhibitors. As we were not able to detect RUNX1-binding sites in the PTK2 promoter, we hypothesized that RUNX1 might regulate micro(mi)RNAs that repress PTK2, such that loss-of-function RUNX1 mutations would result in reduced miRNA expression and derepression of PTK2. Examination of paired RNA-seq and miRNA-seq data from 301 AML cases revealed two miRNAs that positively correlated with RUNX1 expression, contained RUNX1-binding sites in their promoters and were predicted to target PTK2. We show that the hsa-let7a-2-3p and hsa-miR-135a-5p promoters are regulated by RUNX1, and that PTK2 is a direct target of both miRNAs. Even in the absence of RUNX1 mutations, hsa-let7a-2-3p and hsa-miR-135a-5p regulate PTK2 expression, and reduced expression of these two miRNAs sensitizes AML cells to PTK2 inhibition. These data explain how RUNX1 regulates PTK2, and identify potential miRNA biomarkers for targeting AML with PTK2 inhibitors.

MicroRNA-27a-3p targets FoxO signalling to induce tumour-like phenotypes in bile duct cells

BACKGROUND & AIMS

Cholangiocarcinoma (CCA) is a heterogeneous and lethal malignancy, the molecular origins of which remain poorly understood. MicroRNAs (miRs) target diverse signalling pathways, functioning as potent epigenetic regulators of transcriptional output. We aimed to characterise miRNome dysregulation in CCA, including its impact on transcriptome homeostasis and cell behaviour.

METHODS

Small RNA sequencing was performed on 119 resected CCAs, 63 surrounding liver tissues, and 22 normal livers. High-throughput miR mimic screens were performed in three primary human cholangiocyte cultures. Integration of patient transcriptomes and miRseq together with miR screening data identified an oncogenic miR for characterization. MiR-mRNA interactions were investigated by a luciferase assay. MiR-CRISPR knockout cells were generated and phenotypically characterized in vitro (proliferation, migration, colony, mitochondrial function, glycolysis) and in vivo using subcutaneous xenografts.

RESULTS

In total, 13% (140/1,049) of detected miRs were differentially expressed between CCA and surrounding liver tissues, including 135 that were upregulated in tumours. CCA tissues were characterised by higher miRNome heterogeneity and miR biogenesis pathway expression. Unsupervised hierarchical clustering of tumour miRNomes identified three subgroups, including distal CCA-enriched and IDH1 mutant-enriched subgroups. High-throughput screening of miR mimics uncovered 71 miRs that consistently increased proliferation of three primary cholangiocyte models and were upregulated in CCA tissues regardless of anatomical location, among which only miR-27a-3p had consistently increased expression and activity in several cohorts. FoxO signalling was predominantly downregulated by miR-27a-3p in CCA, partially through targeting of FOXO1. MiR-27a knockout increased FOXO1 levels in vitro and in vivo, impeding tumour behaviour and growth.

CONCLUSIONS

The miRNomes of CCA tissues are highly remodelled, impacting transcriptome homeostasis in part through regulation of transcription factors like FOXO1. MiR-27a-3p arises as an oncogenic vulnerability in CCA.

IMPACT AND IMPLICATIONS

Cholangiocarcinogenesis entails extensive cellular reprogramming driven by genetic and non-genetic alterations, but the functional roles of these non-genetic events remain poorly understood. By unveiling global miRNA upregulation in patient tumours and their functional ability to increase proliferation of cholangiocytes, these small non-coding RNAs are implicated as critical non-genetic alterations promoting biliary tumour initiation. These findings identify possible mechanisms for transcriptome rewiring during transformation, with potential implications for patient stratification.

Landscape of MicroRNA Regulatory Network Architecture and Functional Rerouting in Cancer

Somatic mutations are a major source of cancer development, and many driver mutations have been identified in protein coding regions. However, the function of mutations located in miRNA and their target binding sites throughout the human genome remains largely unknown. Here, we built detailed cancer-specific miRNA regulatory networks across 30 cancer types to systematically analyze the effect of mutations in miRNAs and their target sites in 3' untranslated region (3' UTR), coding sequence (CDS), and 5' UTR regions. A total of 3,518,261 mutations from 9,819 samples were mapped to miRNA-gene interactions (mGI). Mutations in miRNAs showed a mutually exclusive pattern with mutations in their target genes in almost all cancer types. A linear regression method identified 148 candidate driver mutations that can significantly perturb miRNA regulatory networks. Driver mutations in 3'UTRs played their roles by altering RNA binding energy and the expression of target genes. Finally, mutated driver gene targets in 3' UTRs were significantly downregulated in cancer and functioned as tumor suppressors during cancer progression, suggesting potential miRNA candidates with significant clinical implications. A user-friendly, open-access web portal (mGI-map) was developed to facilitate further use of this data resource. Together, these results will facilitate novel noncoding biomarker identification and therapeutic drug design targeting the miRNA regulatory networks.

SIGNIFICANCE

A detailed miRNA-gene interaction map reveals extensive miRNA-mediated gene regulatory networks with mutation-induced perturbations across multiple cancers, serving as a resource for noncoding biomarker discovery and drug development.

Defining disease-related modules based on weighted miRNA synergistic network

MicroRNAs (miRNAs) play an important role in the biological process. Their expression and functional changes have been observed in most cancers. Meanwhile, there exists cooperative regulation among miRNAs which is important for studying the mechanisms of complex post-transcriptional regulations. Hence, studying miRNA synergy and identifying miRNA synergistic modules can help understand the development and progression of complex diseases, such as cancers. This work studies miRNA synergy and proposes a new method for defining disease-related modules (DDRM) by combining the knowledge databases and miRNA data. DDRM measures the miRNA synergy not only by the co-regulating target subset but also by the non-common target set to construct the weighted miRNA synergistic network (WMSN). The experiments on twelve the cancer genome atlas (TCGA) datasets showed that the important modules identified by DDRM can well distinguish the cancer samples from the normal samples, and DDRM performed better than the previous method in most cases. An external dataset of prostate cancer was applied to validate the module biomarkers determined by DDRM on the prostate cancer data of TCGA. The area under the receiver operating characteristic curve (AUC) value is 0.92 and the performance is superior. Hence, combining the miRNA synergy networks from the knowledge databases and the miRNA data can determine the important functional modules related to diseases, which is of great significance to the study of disease mechanism.

miR-19-3p Targets PTEN to Regulate Cervical Cancer Cell Proliferation, Invasion, and Autophagy

Background

Cervical cancer is the second most common cancer among women worldwide. Extensive studies have shown that microRNAs (miRNA/miR) can regulate the formation, progression, and metastasis of cancer. The purpose of this study was to investigate the effect of miR-19-3p on the proliferation, invasion, and autophagy of cervical cancer cells and to explore the underlying mechanism.

Methods

SiHa and HeLa cells were transfected with miR-19-3p mimic and inhibitor. miR-19-3p and PTEN expression were detected using real-time quantitative PCR and western blot, respectively. The binding between miR-19-3p and PTEN was predicted using Targetscan7.2 and verified by a dual-luciferase reporter gene assay. The effects of miR-19-3p on cell invasion and proliferation were evaluated by Transwell assays and MTT, respectively. The effect of miR-19-3p on autophagy was observed using fluorescence microscopy.

Results

The expression of miR-19-3p in cervical cancer tissues and SiHa and HeLa cells was significantly upregulated, whereas the expression of PTEN was significantly downregulated. PTEN was one of the direct targets of miR-19-3p. The miR-19-3p mimic significantly reduced the apoptosis rate and autophagy and promoted cell proliferation and invasion of the SiHa and HeLa cells.

Conclusion

In summary, miR-19b-3p can target PTEN to regulate the proliferation, invasion, and autophagy of cervical cancer cells. Our findings indicate the potential of miR-19-3p as a target for cervical cancer treatment in the future.

Circulating miRNA Expression Profiles and Machine Learning Models in Association with Response to Irinotecan-Based Treatment in Metastatic Colorectal Cancer

Colorectal cancer represents a leading cause of cancer-related morbidity and mortality. Despite improvements, chemotherapy remains the backbone of colorectal cancer treatment. The aim of this study is to investigate the variation of circulating microRNA expression profiles and the response to irinotecan-based treatment in metastatic colorectal cancer and to identify relevant target genes and molecular functions. Serum samples from 95 metastatic colorectal cancer patients were analyzed. The microRNA expression was tested with a NucleoSpin miRNA kit (Machnery-Nagel, Germany), and a machine learning approach was subsequently applied for microRNA profiling. The top 10 upregulated microRNAs in the non-responders group were hsa-miR-181b-5p, hsa-miR-10b-5p, hsa-let-7f-5p, hsa-miR-181a-5p, hsa-miR-181d-5p, hsa-miR-301a-3p, hsa-miR-92a-3p, hsa-miR-155-5p, hsa-miR-30c-5p, and hsa-let-7i-5p. Similarly, the top 10 downregulated microRNAs were hsa-let-7d-5p, hsa-let-7c-5p, hsa-miR-215-5p, hsa-miR-143-3p, hsa-let-7a-5p, hsa-miR-10a-5p, hsa-miR-142-5p, hsa-miR-148a-3p, hsa-miR-122-5p, and hsa-miR-17-5p. The upregulation of microRNAs in the miR-181 family and the downregulation of those in the let-7 family appear to be mostly involved with non-responsiveness to irinotecan-based treatment.

OncomiRs as noncoding RNAs having functions in cancer: Their role in immune suppression and clinical implications

Currently, microRNAs have been established as central players in tumorigenesis, but above all, they have opened an important door for our understanding of immune and tumor cell communication. This dialog is largely due to onco-miR transfer from tumor cells to cells of the tumor microenvironment by exosome. This review outlines recent advances regarding the role of oncomiRs in enhancing cancer and how they modulate the cancer-related immune response in the tumor immune microenvironment.

MicroRNAs (miRNAs) are a type of noncoding RNA that are important posttranscriptional regulators of messenger RNA (mRNA) translation into proteins. By regulating gene expression, miRNAs enhance or inhibit cancer development and participate in several cancer biological processes, including proliferation, invasion metastasis, angiogenesis, chemoresistance and immune escape. Consistent with their widespread effects, miRNAs have been categorized as oncogenes (oncomiRs) or tumor suppressor (TS) miRNAs. MiRNAs that promote tumor growth, called oncomiRs, inhibit messenger RNAs of TS genes and are therefore overexpressed in cancer. In contrast, TS miRNAs inhibit oncogene messenger RNAs and are therefore underexpressed in cancer. Endogenous miRNAs regulate different cellular pathways in all cell types. Therefore, they are not only key modulators in cancer cells but also in the cells constituting their microenvironments. Recently, it was shown that miRNAs are also involved in intercellular communication. Indeed, miRNAs can be transferred from one cell type to another where they regulate targeted gene expression. The primary carriers for the transfer of miRNAs from one cell to another are exosomes. Exosomes are currently considered the primary carriers for communication between the tumor and its surrounding stromal cells to support cancer progression and drive immune suppression. Exosome and miRNAs are seen by many as a hope for developing a new class of targeted therapy. This review outlines recent advances in understanding the role of oncomiRs in enhancing cancer and how they promote its aggressive characteristics and deeply discusses the role of oncomiRs in suppressing the anticancer immune response in its microenvironment. Additionally, further understanding the mechanism of oncomiR-related immune suppression will facilitate the use of miRNAs as biomarkers for impaired antitumor immune function, making them ideal immunotherapy targets.

Transcriptomics and solid tumors: The next frontier in precision cancer medicine

Transcriptomics, which encompasses assessments of alternative splicing and alternative polyadenylation, identification of fusion transcripts, explorations of noncoding RNAs, transcript annotation, and discovery of novel transcripts, is a valuable tool for understanding cancer mechanisms and identifying biomarkers. Recent advances in high-throughput technologies have enabled large-scale gene expression profiling. Importantly, RNA expression profiling of tumor tissue has been successfully used to determine clinically actionable molecular alterations. The WINTHER precision medicine clinical trial was the first prospective trial in diverse solid malignancies that assessed both genomics and transcriptomics to match treatments to specific molecular alterations. The use of transcriptome analysis in WINTHER and other trials increased the number of targetable -omic changes compared to genomic profiling alone. Other applications of transcriptomics involve the evaluation of tumor and circulating noncoding RNAs as predictive and prognostic biomarkers, the improvement of risk stratification by the use of prognostic and predictive multigene assays, the identification of fusion transcripts that drive tumors, and an improved understanding of the impact of DNA changes as some genomic alterations are silenced at the RNA level. Finally, RNA sequencing and gene expression analysis have been incorporated into clinical trials to identify markers predicting response to immunotherapy. Many issues regarding the complexity of the analysis, its reproducibility and variability, and the interpretation of the results still need to be addressed. The integration of transcriptomics with genomics, proteomics, epigenetics, and tumor immune profiling will improve biomarker discovery and our understanding of disease mechanisms and, thereby, accelerate the implementation of precision oncology.

MiRNA expression profiling in adenocarcinoma and squamous cell lung carcinoma reveals both common and specific deregulated microRNAs

The current study investigated the expression signatures of miRNAs in lung adenocarcinoma (LUAD) and squamous cell lung carcinoma (LUSC). miRNA profiling was performed using microarray in 12 LUAD and 12 LUSC samples and adjacent normal tissues. In LUAD, 107 miRNAs were significantly deregulated, whereas 235 miRNAs were deregulated in LUSC. Twenty-six miRNAs were common between the 2 cancer subtypes and 8 were prioritized for validation, in addition to 6 subtype-specific miRNAs. The RT-qPCR validation samples included 50 LUAD, 50 LUSC, and adjacent normal tissues. Eight miRNAs were validated in LUAD: 3 upregulated - miR-7-5p, miR-375-5p, miR-6785-3p, and 5 downregulated - miR-101-3p, miR-139-5p, miR-140-3p, miR-144-3p, miR-195-5p. Ten miRNAs were validated in the LUSC group: 3 upregulated - miR-7-5p, miR-21-3p, miR-650, and 7 downregulated - miR-95-5p, miR-140-3p, miR-144-3p, miR-195-5p, miR-375, miR-744-3p, and miR-4689-3p. Reactome pathway analysis revealed that the target genes of the deregulated miRNAs in LUAD were significantly enriched in cell cycle, membrane trafficking, gene expression processes, and EGFR signaling, while in LUSC, they were enriched in the immune system, transcriptional regulation by TP53, and FGFR signaling. This study identified distinct miRNA profiles in LUSC and LUAD, which are common and specific miRNAs that could be further investigated as biomarkers for diagnosis and prognosis.

PUMILIO competes with AUF1 to control DICER1 RNA levels and miRNA processing

DICER1 syndrome is a cancer pre-disposition disorder caused by mutations that disrupt the function of DICER1 in miRNA processing. Studying the molecular, cellular and oncogenic effects of these mutations can reveal novel mechanisms that control cell homeostasis and tumor biology. Here, we conduct the first analysis of pathogenic DICER1 syndrome allele from the DICER1 3'UTR. We find that the DICER1 syndrome allele, rs1252940486, abolishes interaction with the PUMILIO RNA binding protein with the DICER1 3'UTR, resulting in the degradation of the DICER1 mRNA by AUF1. This single mutational event leads to diminished DICER1 mRNA and protein levels, and widespread reprogramming of miRNA networks. The in-depth characterization of the rs1252940486 DICER1 allele, reveals important post-transcriptional regulatory events that control DICER1 levels.

MIO: MicroRNA target analysis system for Immuno-Oncology

Summary

MicroRNAs have been shown to be able to modulate the tumor microenvironment and the immune response and hence could be interesting biomarkers and therapeutic targets in immuno-oncology; however, dedicated analysis tools are missing. Here, we present a user-friendly web platform MIO and a Python toolkit miopy integrating various methods for visualization and analysis of provided or custom bulk microRNA and gene expression data. We include regularized regression and survival analysis and provide information of 40 microRNA target prediction tools as well as a collection of curated immune related gene and microRNA signatures and processed TCGA data including estimations of infiltrated immune cells and the immunophenoscore. The integration of several machine learning methods enables the selection of prognostic and predictive microRNAs and gene interaction network biomarkers.

Availability and implementation

https://mio.icbi.at, https://github.com/icbi-lab/mio and https://github.com/icbi-lab/miopy.

Supplementary information

Supplementary data are available at Bioinformatics online.

Computing microRNA-gene interaction networks in pan-cancer using miRDriver

DNA copy number aberrated regions in cancer are known to harbor cancer driver genes and the short non-coding RNA molecules, i.e., microRNAs. In this study, we integrated the multi-omics datasets such as copy number aberration, DNA methylation, gene and microRNA expression to identify the signature microRNA-gene associations from frequently aberrated DNA regions across pan-cancer utilizing a LASSO-based regression approach. We studied 7294 patient samples associated with eighteen different cancer types from The Cancer Genome Atlas (TCGA) database and identified several cancer-specific and common microRNA-gene interactions enriched in experimentally validated microRNA-target interactions. We highlighted several oncogenic and tumor suppressor microRNAs that were cancer-specific and common in several cancer types. Our method substantially outperformed the five state-of-art methods in selecting significantly known microRNA-gene interactions in multiple cancer types. Several microRNAs and genes were found to be associated with tumor survival and progression. Selected target genes were found to be significantly enriched in cancer-related pathways, cancer hallmark and Gene Ontology (GO) terms. Furthermore, subtype-specific potential gene signatures were discovered in multiple cancer types.

Molecular Pathology of Lung Cancer

This overview of the molecular pathology of lung cancer includes a review of the most salient molecular alterations of the genome, transcriptome, and the epigenome. The insights provided by the growing use of next-generation sequencing (NGS) in lung cancer will be discussed, and interrelated concepts such as intertumor heterogeneity, intratumor heterogeneity, tumor mutational burden, and the advent of liquid biopsy will be explored. Moreover, this work describes how the evolving field of molecular pathology refines the understanding of different histologic phenotypes of non-small-cell lung cancer (NSCLC) and the underlying biology of small-cell lung cancer. This review will provide an appreciation for how ongoing scientific findings and technologic advances in molecular pathology are crucial for development of biomarkers, therapeutic agents, clinical trials, and ultimately improved patient care.

Onco-miR-21 Promotes Stat3-Dependent Gastric Cancer Progression

MicroRNA-21 (miR-21) is a small, non-coding RNA overexpressed in gastric cancer and many other solid malignancies, where it exhibits both pro-and anti-tumourigenic properties. However, the pathways regulating miR-21 and the consequences of its inhibition in gastric cancer remain incompletely understood. By exploiting the spontaneous Stat3-dependent formation of inflammation-associated gastric tumors in Gp130^F/F mice, we functionally established miR-21 as a Stat3-controlled driver of tumor growth and progression. We reconciled our discoveries by identifying several conserved Stat3 binding motifs upstream of the miR-21 gene promoter, and showed that the systemic administration of a miR-21-specific antisense oligonucleotide antagomir reduced the established gastric tumor burden in Gp130^F/F mice. We molecularly delineated the therapeutic benefits of miR-21 inhibition with the functional restoration of PTEN in vitro and in vivo, alongside an attenuated epithelial-to-mesenchymal transition and the extracellular matrix remodeling phenotype of tumors. We corroborated our preclinical findings by correlating high STAT3 and miR-21 expression with the reduced survival probability of gastric cancer patients. Collectively, our results provide a molecular framework by which miR-21 mediates inflammation-associated gastric cancer progression, and establish miR-21 as a robust therapeutic target for solid malignancies characterized by excessive Stat3 activity.

Hsa-miR-3651 could serve as a novel predictor for in-breast recurrence via FRMD3

Background

MicroRNAs are small non-coding RNAs with pivotal regulatory functions in multiple cellular processes. Their significance as molecular predictors for breast cancer was demonstrated in the past 15 years. The aim of this study was to elucidate the role of hsa-miR-3651 for predicting of local control (LC) in early breast cancer.

Results

By means of high-throughput technology, hsa-miR-3651 was found to be differentially expressed between patients who experienced local relapse compared to those without (N  =  23; p  =  0.0035). This result could be validated in an independent cohort of 87 patients using RT-qPCR (p  <  0.0005). In a second analysis step with a chip-based microarray containing 70,523 probes of potential target molecules, FERM domain protein 3 (FRMD3) was found to be the most down-regulated protein (N  =  21; p  =  0.0016). Computational analysis employing different prediction algorithms revealed FRMD3 as a likely downstream target of hsa-miR-3651 with an 8mer binding site between the two molecules. This could be validated in an independent patient set (N  =  20, p  =  0.134).

Conclusion

The current study revealed that hsa-miR-3651 is a predictor of LC in early breast cancer via its putative target protein FRMD3. Since microRNAs interfere in multiple pathways, the results of this hypothesis generating study may contribute to the development of tailored therapies for breast cancer in the future.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12282-021-01308-y.

MammaPrint and BluePrint comprehensively capture the cancer hallmarks in early-stage breast cancer patients

MammaPrint® (MP) is a 70‐gene signature that stratifies early‐stage breast cancer patients into low‐ and high risk of distant relapse. Further stratification of MP risk results identifies four risk subgroups, ultra‐low (UL), low, high 1, and high 2, with specific prognostic and predictive outcomes. BluePrint® (BP) is an 80‐gene signature that classifies breast tumors as basal, luminal, or HER2 molecular subtype. To gain insight into their biological significance, we annotated the MP 70‐ and BP 80‐genes with respect to the 10 hallmarks of cancer (HoC). Furthermore, we related gene expression profiles of the extreme ends of the MP low‐ and high‐risk patients (here called, ultra‐low (UL) and ultra‐high (UH) or High2, respectively), to the 10 HoC per BP subtype by differential gene expression and pathway analysis. MP and BP gene functions reflected all 10 HoCs. Most MP and BP genes were associated with sustaining proliferative signaling, followed by genome instability and mutation categories. Based on the gene expression profiles, UL and UH subgroup pathways were down ‐or upregulated, respectively, reflecting proliferative and metastatic features, such as G2M checkpoint, DNA repair, oxidative phosphorylation, immune invasion, PI3K/AKT/mTOR signaling, and hypoxia pathways. Notably, the UH HER2‐type was enriched in several immune signaling pathways, such as IL2/STAT5 signaling and TNFα signaling via NFκB. Our results show that MP and BP gene signatures represent and capture all 10 HoCs and highlight underlying biological processes of MP extreme samples, which might guide treatment decisions as the signature captures the full spectrum of early breast cancers.

Network potential identifies therapeutic miRNA cocktails in Ewing sarcoma

MicroRNA (miRNA)-based therapies are an emerging class of targeted therapeutics with many potential applications. Ewing Sarcoma patients could benefit dramatically from personalized miRNA therapy due to inter-patient heterogeneity and a lack of druggable (to this point) targets. However, because of the broad effects miRNAs may have on different cells and tissues, trials of miRNA therapies have struggled due to severe toxicity and unanticipated immune response. In order to overcome this hurdle, a network science-based approach is well-equipped to evaluate and identify miRNA candidates and combinations of candidates for the repression of key oncogenic targets while avoiding repression of essential housekeeping genes. We first characterized 6 Ewing sarcoma cell lines using mRNA sequencing. We then estimated a measure of tumor state, which we term network potential, based on both the mRNA gene expression and the underlying protein-protein interaction network in the tumor. Next, we ranked mRNA targets based on their contribution to network potential. We then identified miRNAs and combinations of miRNAs that preferentially act to repress mRNA targets with the greatest influence on network potential. Our analysis identified TRIM25, APP, ELAV1, RNF4, and HNRNPL as ideal mRNA targets for Ewing sarcoma therapy. Using predicted miRNA-mRNA target mappings, we identified miR-3613-3p, let-7a-3p, miR-300, miR-424-5p, and let-7b-3p as candidate optimal miRNAs for preferential repression of these targets. Ultimately, our work, as exemplified in the case of Ewing sarcoma, describes a novel pipeline by which personalized miRNA cocktails can be designed to maximally perturb gene networks contributing to cancer progression.

Biological Role and Clinical Implications of microRNAs in BRCA Mutation Carriers

Women with pathogenic germline mutations in BRCA1 and BRCA2 genes have an increased risk to develop breast and ovarian cancer. There is, however, a high interpersonal variability in the modality and timing of tumor onset in those subjects, thus suggesting a potential role of other individual’s genetic, epigenetic, and environmental risk factors in modulating the penetrance of BRCA mutations. MicroRNAs (miRNAs) are small noncoding RNAs that can modulate the expression of several genes involved in cancer initiation and progression. MiRNAs are dysregulated at all stages of breast cancer and although they are accessible and evaluable, a standardized method for miRNA assessment is needed to ensure comparable data analysis and accuracy of results. The aim of this review was to highlight the role of miRNAs as potential biological markers for BRCA mutation carriers. In particular, biological and clinical implications of a link between lifestyle and nutritional modifiable factors, miRNA expression and germline BRCA1 and BRCA2 mutations are discussed with the knowledge of the best available scientific evidence.

EVAtlas: a comprehensive database for ncRNA expression in human extracellular vesicles

Extracellular vesicles (EVs) packing various molecules play vital roles in intercellular communication. Non-coding RNAs (ncRNAs) are important functional molecules and biomarkers in EVs. A comprehensive investigation of ncRNAs expression in EVs under different conditions is a fundamental step for functional discovery and application of EVs. Here, we curated 2030 small RNA-seq datasets for human EVs (1506 sEV and 524 lEV) in 24 conditions and over 40 diseases. We performed a unified reads dynamic assignment algorithm (RDAA) considering mismatch and multi-mapping reads to quantify the expression profiles of seven ncRNA types (miRNA, snoRNA, piRNA, snRNA, rRNA, tRNA and Y RNA). We constructed EVAtlas (http://bioinfo.life.hust.edu.cn/EVAtlas), a comprehensive database for ncRNA expression in EVs with four functional modules: (i) browse and compare the distribution of ncRNAs in EVs from 24 conditions and eight sources (plasma, serum, saliva, urine, sperm, breast milk, primary cell and cell line); (ii) prioritize candidate ncRNAs in condition related tissues based on their expression; (iii) explore the specifically expressed ncRNAs in EVs from 24 conditions; (iv) investigate ncRNA functions, related drugs, target genes and EVs isolation methods. EVAtlas contains the most comprehensive ncRNA expression in EVs and will be a key resource in this field.

Non-Coding Variants in Cancer: Mechanistic Insights and Clinical Potential for Personalized Medicine

The cancer genome is characterized by extensive variability, in the form of Single Nucleotide Polymorphisms (SNPs) or structural variations such as Copy Number Alterations (CNAs) across wider genomic areas. At the molecular level, most SNPs and/or CNAs reside in non-coding sequences, ultimately affecting the regulation of oncogenes and/or tumor-suppressors in a cancer-specific manner. Notably, inherited non-coding variants can predispose for cancer decades prior to disease onset. Furthermore, accumulation of additional non-coding driver mutations during progression of the disease, gives rise to genomic instability, acting as the driving force of neoplastic development and malignant evolution. Therefore, detection and characterization of such mutations can improve risk assessment for healthy carriers and expand the diagnostic and therapeutic toolbox for the patient. This review focuses on functional variants that reside in transcribed or not transcribed non-coding regions of the cancer genome and presents a collection of appropriate state-of-the-art methodologies to study them.

Reactivation of tumour suppressor in breast cancer by enhancer switching through NamiRNA network

Dysfunction of Tumour Suppressor Genes (TSGs) is a common feature in carcinogenesis. Epigenetic abnormalities including DNA hypermethylation or aberrant histone modifications in promoter regions have been described for interpreting TSG inactivation. However, in many instances, how TSGs are silenced in tumours are largely unknown. Given that miRNA with low expression in tumours is another recognized signature, we hypothesize that low expression of miRNA may reduce the activity of TSG related enhancers and further lead to inactivation of TSG during cancer development. Here, we reported that low expression of miRNA in cancer as a recognized signature leads to loss of function of TSGs in breast cancer. In 157 paired breast cancer and adjacent normal samples, tumour suppressor gene GPER1 and miR-339 are both downregulated in Luminal A/B and Triple Negative Breast Cancer subtypes. Mechanistic investigations revealed that miR-339 upregulates GPER1 expression in breast cancer cells by switching on the GPER1 enhancer, which can be blocked by enhancer deletion through the CRISPR/Cas9 system. Collectively, our findings reveal novel mechanistic insights into TSG dysfunction in cancer development, and provide evidence that reactivation of TSG by enhancer switching may be a promising alternative strategy for clinical breast cancer treatment.

Molecular Regulation of Paused Pluripotency in Early Mammalian Embryos and Stem Cells

The energetically costly mammalian investment in gestation and lactation requires plentiful nutritional sources and thus links the environmental conditions to reproductive success. Flexibility in adjusting developmental timing enhances chances of survival in adverse conditions. Over 130 mammalian species can reversibly pause early embryonic development by switching to a near dormant state that can be sustained for months, a phenomenon called embryonic diapause. Lineage-specific cells are retained during diapause, and they proliferate and differentiate upon activation. Studying diapause thus reveals principles of pluripotency and dormancy and is not only relevant for development, but also for regeneration and cancer. In this review, we focus on the molecular regulation of diapause in early mammalian embryos and relate it to maintenance of potency in stem cells in vitro. Diapause is established and maintained by active rewiring of the embryonic metabolome, epigenome, and gene expression in communication with maternal tissues. Herein, we particularly discuss factors required at distinct stages of diapause to induce, maintain, and terminate dormancy.

miR-4323 targets hepatoma-derived growth factor (HDGF) to suppress colorectal cancer cell proliferation

MicroRNAs (miRNAs) are regulators of cancer progression via directly binding to the 3' untranslated region (3'UTR) of target genes to control the activity of signaling network. Recent studies have revealed the function of several miRNAs in colorectal cancer, however, there are still numerous miRNAs which have not been studied yet. Herein, we showed that miR-4323 was a downregulated miRNA according to previous microarray data. The downregulation of miR-4323 was further confirmed in colorectal tumors via RT-qPCR. miR-4323 overexpression decreased cell proliferation rate via induction of cell apoptosis in colorectal cancer cells. Mechanistically, miR-4323 decreased β-catenin and its downstream genes including c-Myc and MMP9 in colorectal cancer cells, indicating the inactivation of Wnt signaling. HDGF, an anti-apoptotic protein, was predicted by several software as a potential target of miR-4323. HDGF was experimentally verified as a target gene of miR-4323 using dual luciferase reporter assay. Ectopic expression of HDGF attenuated the effect of miR-4323 on cell proliferation and apoptosis in cells. Altogether, the data demonstrate a critical role of miR-4323 in the regulation of colorectal cancer.