MicroRNA-99a/100 promotes apoptosis by targeting mTOR in human esophageal squamous cell carcinoma

MicroRNA-99 family in cancer: molecular mechanisms for clinical applications

MicroRNAs (miRNAs) are a class of non-coding RNA sequences that regulate gene expression post-transcriptionally. The miR-99 family, which is highly evolutionarily conserved, comprises three homologs: miR-99a, miR-99b, and miR-100. Its members are under-expressed in most cancerous tissues, suggesting their cancer-repressing properties in multiple cancers; however, in some contexts, they also promote malignant lesion progression. MiR-99 family members target numerous genes involved in various tumor-related processes such as tumorigenesis, proliferation, cell-cycle regulation, apoptosis, invasion, and metastasis. We review the recent research on this family, summarize its implications in cancer, and explore its potential as a biomarker and cancer therapeutic target. This review contributes to the clinical translation of the miR-99 family members.

Emerging insights into the role of natural products and miRNAs in psoriasis: from pathophysiology to precision medicine

Psoriasis is a sustainable skin disease characterized by inflammation resulting from the interaction between immune cells and keratinocytes. Significant advancements have been achieved in studying the molecular process behind noncoding and coding genes, leading to valuable insights for clinical therapy. Nevertheless, our comprehension of this intricate ailment remains ambiguous. Natural products such as curcumin, vitamin D, omega-3, vitamin E, psoralen, gallic acid (GA), and resveratrol offer a promising alternative or adjunct therapy for psoriasis by modulating multiple pathways and exhibiting fewer side effects compared to conventional treatments. MicroRNAs (miRNAs) are short RNAs that are involved in regulating gene expression after transcription, namely by suppressing gene activity. Recent research on miRNAs has uncovered their significant significance in the development of psoriasis. In this review, we examined the latest developments in the investigation of miRNAs in psoriasis. Previous studies have revealed that imbalanced miRNAs in psoriasis have a significant impact on the processes of keratinocyte differentiation, proliferation, and the progression of inflammation. Furthermore, miRNAs exert an impact on the activity of immune cells involved in psoriasis, such as Langerhans cells, dendritic cells, and CD4+ T cells. Furthermore, we explore potential miRNA-focused treatment options for psoriasis, including the localized administration of external miRNA mimics, and miRNA inhibitors. The effectiveness of natural products and miRNAs in treating psoriasis, as well as the signaling pathways that may be involved, are summarized in this article.

Downregulation of miR-100-5p in cancer-associated fibroblast-derived exosomes facilitates lymphangiogenesis in esophageal squamous cell carcinoma

BACKGROUND

Esophageal squamous cell carcinoma (ESCC), an aggressive gastrointestinal tumor, often has high early lymphatic metastatic potential. Cancer-associated fibroblasts (CAFs) are primary components in tumor microenvironment (TME), and the impact of CAFs and its derived exosomes on lymphangiogenesis remains elusive.

MATERIALS AND METHODS

CAFs and the microlymphatic vessel density (MLVD) in ESCC was examined. Exosomes were extracted from primary normal fibroblast (NFs) and CAFs. Subsequently, tumor-associated lymphatic endothelial cells (TLECs) were treated with these exosomes, and the effect on their biological behavior was examined. miR-100-5p was selected as the target miRNA, and its effect on TLECs was examined. The target of miR-100-5p was predicted and confirmed. Subsequently, IGF1R, PI3K, AKT, and p-AKT expression in TLECs and tumors treated with exosomes and miR-100-5p were examined.

RESULTS

A large number of CAFs and microlymphatic vessels were present in ESCC, leading to a poor prognosis. CAF-derived exosomes promoted proliferation, migration, invasion, and tube formation in TLECs. Further, they also enhanced lymphangiogenesis in ESCC xenografts. miR-100-5p levels were significantly lower in CAF-derived exosomes than in NF-derived exosomes. miR-100-5p inhibited proliferation, migration, invasion, and tube formation in TLECs. Further, miR-100-5p inhibited lymphangiogenesis in ESCC xenografts. Mechanistic studies revealed that this inhibition was mediated by the miR-100-5p-induced inhibition of IGF1R/PI3K/AKT axis.

CONCLUSION

Taken together, our study demonstrates that CAF-derived exosomes with decreased miR-100-5p levels exhibit pro-lymphangiogenesis capacity, suggesting a possibility of targeting IGF1R/PI3K/AKT axis as a strategy to inhibit lymphatic metastasis in ESCC.

Targeting mTOR as a Cancer Therapy: Recent Advances in Natural Bioactive Compounds and Immunotherapy

The mammalian target of rapamycin (mTOR) is a highly conserved serine/threonine-protein kinase, which regulates many biological processes related to metabolism, cancer, immune function, and aging. It is an essential protein kinase that belongs to the phosphoinositide-3-kinase (PI3K) family and has two known signaling complexes, mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2). Even though mTOR signaling plays a critical role in promoting mitochondria-related protein synthesis, suppressing the catabolic process of autophagy, contributing to lipid metabolism, engaging in ribosome formation, and acting as a critical regulator of mRNA translation, it remains one of the significant signaling systems involved in the tumor process, particularly in apoptosis, cell cycle, and cancer cell proliferation. Therefore, the mTOR signaling system could be suggested as a cancer biomarker, and its targeting is important in anti-tumor therapy research. Indeed, its dysregulation is involved in different types of cancers such as colon, neck, cervical, head, lung, breast, reproductive, and bone cancers, as well as nasopharyngeal carcinoma. Moreover, recent investigations showed that targeting mTOR could be considered as cancer therapy. Accordingly, this review presents an overview of recent developments associated with the mTOR signaling pathway and its molecular involvement in various human cancer types. It also summarizes the research progress of different mTOR inhibitors, including natural and synthetised compounds and their main mechanisms, as well as the rational combinations with immunotherapies.

Exploiting the Molecular Basis of Oesophageal Cancer for Targeted Therapies and Biomarkers for Drug Response: Guiding Clinical Decision-Making

Worldwide, oesophageal cancer is the sixth leading cause of deaths related to cancer and represents a major health concern. Sub-Saharan Africa is one of the regions of the world with the highest incidence and mortality rates for oesophageal cancer and most of the cases of oesophageal cancer in this region are oesophageal squamous cell carcinoma (OSCC). The development and progression of OSCC is characterized by genomic changes which can be utilized as diagnostic or prognostic markers. These include changes in the expression of various genes involved in signaling pathways that regulate pathways that regulate processes that are related to the hallmarks of cancer, changes in the tumor mutational burden, changes in alternate splicing and changes in the expression of non-coding RNAs such as miRNA. These genomic changes give rise to characteristic profiles of altered proteins, transcriptomes, spliceosomes and genomes which can be used in clinical applications to monitor specific disease related parameters. Some of these profiles are characteristic of more aggressive forms of cancer or are indicative of treatment resistance or tumors that will be difficult to treat or require more specialized specific treatments. In Sub-Saharan region of Africa there is a high incidence of viral infections such as HPV and HIV, which are both risk factors for OSCC. The genomic changes that occur due to these infections can serve as diagnostic markers for OSCC related to viral infection. Clinically this is an important distinction as it influences treatment as well as disease progression and treatment monitoring practices. This underlines the importance of the characterization of the molecular landscape of OSCC in order to provide the best treatment, care, diagnosis and screening options for the management of OSCC.

The Cross Talk Between p53 and mTOR Pathways in Response to Physiological and Genotoxic Stresses

The tumor suppressor p53 is activated upon multiple cellular stresses, including DNA damage, oncogene activation, ribosomal stress, and hypoxia, to induce cell cycle arrest, apoptosis, and senescence. Mammalian target of rapamycin (mTOR), an evolutionarily conserved serine/threonine protein kinase, serves as a central regulator of cell growth, proliferation, and survival by coordinating nutrients, energy, growth factors, and oxygen levels. p53 dysfunction and mTOR pathway hyperactivation are hallmarks of human cancer. The balance between response to stresses or commitment to cell proliferation and survival is governed by various regulatory loops between the p53 and mTOR pathways. In this review, we first briefly introduce the tumor suppressor p53 and then describe the upstream regulators and downstream effectors of the mTOR pathway. Next, we discuss the role of p53 in regulating the mTOR pathway through its transcriptional and non-transcriptional effects. We further describe the complicated role of the mTOR pathway in modulating p53 activity. Finally, we discuss the current knowledge and future perspectives on the coordinated regulation of the p53 and mTOR pathways.

MicroRNA-99a-5p suppresses cell proliferation, migration, and invasion by targeting isoprenylcysteine carboxylmethyltransferase in oral squamous cell carcinoma

BACKGROUND

MicroRNA (miR)-99a-5p acts as a tumor suppressor in several tumors, including bladder cancer and breast cancer, but its biological function in oral squamous cell carcinoma (OSCC) is poorly understood.

METHODS

miR-99a-5p expression was determined in OSCC tissues and cell lines using quantitative reverse transcription polymerase chain reaction (RT-qPCR). Cell proliferation was assessed by the Cell Counting Kit-8 assay and colony formation assay. Wound healing and Transwell assays were used to analyze migration and invasion abilities, respectively, in OSCC cells. The luciferase reporter assay, RT-qPCR, and western blotting were used to determine the relationship between miR-99a-5p and isoprenylcysteine carboxylmethyltransferase (ICMT).

RESULTS

miR-99a-5p expression in OSCC tissues and cell lines was significantly decreased compared with corresponding controls, and was significantly associated with clinical stage and lymph node metastasis in OSCC. Functional assays revealed that miR-99a-5p overexpression significantly inhibited the proliferation, migration, and invasion abilities of CAL-27 and TCA-8113 OSCC cells. miR-99a-5p was found to directly target ICMT, while ICMT restoration reversed the role of miR-99a-5p in OSCC cells.

CONCLUSIONS

Our results indicate that miR-99a-5p-mediates the down-regulation of ICMT, which could be used as a novel potential therapeutic target for OSCC treatment.

The miRNA: a small but powerful RNA for COVID-19

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a severe and rapidly evolving epidemic. Now, although a few drugs and vaccines have been proved for its treatment and prevention, little systematic comments are made to explain its susceptibility to humans. A few scattered studies used bioinformatics methods to explore the role of microRNA (miRNA) in COVID-19 infection. Combining these timely reports and previous studies about virus and miRNA, we comb through the available clues and seemingly make the perspective reasonable that the COVID-19 cleverly exploits the interplay between the small miRNA and other biomolecules to avoid being effectively recognized and attacked from host immune protection as well to deactivate functional genes that are crucial for immune system. In detail, SARS-CoV-2 can be regarded as a sponge to adsorb host immune-related miRNA, which forces host fall into dysfunction status of immune system. Besides, SARS-CoV-2 encodes its own miRNAs, which can enter host cell and are not perceived by the host's immune system, subsequently targeting host function genes to cause illnesses. Therefore, this article presents a reasonable viewpoint that the miRNA-based interplays between the host and SARS-CoV-2 may be the primary cause that SARS-CoV-2 accesses and attacks the host cells.

Involvement of long non-coding RNAs in the progression of esophageal cancer

Esophageal cancer (EC) is one of the most common malignant tumors of the digestive system with high incidence and mortality rate worldwide. Therefore, exploring the pathogenesis of EC and searching for new targeted therapies are the current research hotspot for EC treatment. Long non‐coding RNAs (lncRNAs) are endogenous RNAs with more than 200 nucleotides, but without protein‐coding function. In recent years, lncRNAs have gradually become the focuses in the field of non‐coding RNA. Some lncRNAs have been proved to be closely related to the pathogenesis of EC. Many lncRNAs are abnormally expressed in EC and participate in many biological processes including cell proliferation, apoptosis, and metastasis by inhibiting or promoting target gene expression. LncRNAs can also regulate the progression of EC through epithelial‐mesenchymal transformation (EMT), which is closely related to the occurrence, development, and prognosis of EC. In this article, we review and discuss the involvement of lncRNAs in the progression of EC.

Mechanosensitive Non-Coding RNAs in Osteogenesis of Mesenchymal Stem Cells

In bone tissue engineering, tailored biomaterials mimicking mesenchymal stem cells (MSCs) niche could regulate cell behavior and fate decision. The mechanisms, however, remain obscure. Recently, increasing evidence has shown that non-coding RNAs (ncRNAs) are critical modulators of the mechano-induced MSCs' responses. Mechanosensitive ncRNAs could convert various physical forces into biochemical signals, and orchestrate signaling networks that regulate the osteogenic differentiation of MSCs in their unique microenvironment. In this review, we focus on the mechanosensitive ncRNAs which could interpret mechanical stimuli during the osteogenesis of MSCs, summarize the signaling pathway networks by which these ncRNAs drive MSCs fate, and point out the limitations and the areas waiting for further exploration.

Comp34 displays potent preclinical antitumor efficacy in triple-negative breast cancer via inhibition of NUDT3-AS4, a novel oncogenic long noncoding RNA

The abnormal PI3K/AKT/mTOR pathway is one of the most common genomic abnormalities in breast cancers including triple-negative breast cancer (TNBC), and pharmacologic inhibition of these aberrations has shown activity in TNBC patients. Here, we designed and identified a small-molecule Comp34 that suppresses both AKT and mTOR protein expression and exhibits robust cytotoxicity towards TNBC cells but not nontumorigenic normal breast epithelial cells. Mechanically, long noncoding RNA (lncRNA) AL354740.1-204 (also named as NUDT3-AS4) acts as a microRNA sponge to compete with AKT1/mTOR mRNAs for binding to miR-99s, leading to decrease in degradation of AKT1/mTOR mRNAs and subsequent increase in AKT1/mTOR protein expression. Inhibition of lncRNA-NUDT3-AS4 and suppression of the NUDT3-AS4/miR-99s association contribute to Comp34-affected biologic pathways. In addition, Comp34 alone is effective in cells with secondary resistance to rapamycin, the best-known inhibitor of mTOR, and displays a greater in vivo antitumor efficacy and lower toxicity than rapamycin in TNBC xenografted models. In conclusion, NUDT3-AS4 may play a proproliferative role in TNBC and be considered a relevant therapeutic target, and Comp34 presents promising activity as a single agent to inhibit TNBC through regulation of NUDT3-AS4 and miR-99s.

miR-100 inhibits cell proliferation in mantle cell lymphoma by targeting mTOR

Background

miR-100 is reported to be associated with cell proliferation and apoptosis. However, the function of miR-100 in mantle cell lymphoma (MCL) is unknown. The purpose of this study is to analyze the abnormal expression of miR-100 and mTOR in MCL together with their potential biological function and pathogenesis.

Method

Eighteen MCL tissue samples and 3 cell lines (Jeko-1, Mino, Granta-519) were investigated in this research study, while eighteen samples of proliferative lymphadenitis from patients and peripheral lymphocyte cells from healthy volunteers served as controls. The expression and alteration of miR-100 and mTOR mRNA were detected by RT-PCR. The expression and alteration of mTOR protein were explored by Western blot. LV-miR-100-up and LV-mTOR-RNAi were constructed and transfected by lentivirus transfection. Cell proliferation, cell apoptosis and the cell cycle were detected using CCK-8 and flow cytometry. Bioinformatics prediction software was used to predict the miR-100 target gene of mTOR. A double luciferase experiment was used to verify miR-100 targeting at the mTOR-3′-UTR. The interaction between miR-100 and mTOR was further studied using recovery experiments. GraphPad Prism 7 software (version 7.2) was used for statistical analysis, and a P value < 0.05 was considered statistically significant.

Results

We found that the expression of miR-100 mRNA in MCL tissues and cell lines was lower, while that of the mTOR protein was higher. There was a negative correlation between miR-100 and mTOR in both MCL tissues and cell lines. Promoting miR-100 and inhibiting mTOR could inhibit cell proliferation, induce cell apoptosis and block the cell cycle in the G1 phase. A double luciferase reporter assay showed that mTOR was one of the target genes of miR-100. The recovery experiment demonstrated that PV-mTOR-up partially set off the effect of LV-miR-100-up on decreasing mTOR expression, inhibiting proliferation, inducing apoptosis and blocking the cell cycle in G1 phase in both Jeko-1 and Mino cells.

Conclusions

Abnormal expression of miR-100 and mTOR was found in MCL, which included downregulation of miR-100 and upregulation of mTOR. The expression of mTOR is negatively correlated with miR-100. It may play an important role in MCL pathogenesis. miR-100 up-regulation can inhibit cell proliferation, promote cell apoptosis, and inhibit cell cycle in G1 phase by targeting the mTOR gene. miR-100 may potentially be an anti-mantle cell lymphoma gene.

Allergic Inflammation Alters microRNA Expression Profile in Adipose Tissue in the Rat

Adipose tissue is a major source of circulating exosomal microRNAs (miRNAs) that are modulators of the immune response in various types of tissues and organs, including airways. Still, no evidence exists if allergic airway inflammation may affect fat tissue inflammation via alterations in the miRNA expression profile. Therefore, we investigated the miRNA expression profile in the adipose tissue upon induced allergic inflammation in the airways in the rat. Brown Norway rats were chronically sensitized to house dust mite extract for seven weeks. Body composition was performed using MiniSpec Plus. The eosinophil count and the total IgE level were determined to confirm the induction of allergic inflammation. MiRNA expression profiling was done using the next-generation sequencing with validation by qPCR. We found that allergic airway inflammation significantly increased fat in adipose tissue, glucose concentration, and the gene expression of adipose tissue-derived proinflammatory peptides (leptin, TNFα). In miRNA-seq analysis, we showed significant differences in the expression of 36 mature miRNAs, three precursors, and two miRNA families in adipose tissue of allergic rats. Two miRNAs—miRNA-151-5p and miRNA-423-3p—showed significantly increased expression in qPCR in adipose tissue and lungs of sensitized animals. Allergic airway inflammation affects fat tissue and alters miRNA expression profile in adipose tissue in the rat.

The CXCR4-Dependent LASP1-Ago2 Interaction in Triple-Negative Breast Cancer

The CXCR4-LASP1 axis is an emerging target in the field of breast cancer metastasis. C-X-C chemokine receptor type 4 (CXCR4) mediates directed cell migration when activated by its cognate ligand CXCL12. LIM and SH3 Protein 1 (LASP1) is a critical node in the CXCR4 signaling pathway, as its deficiency blocks CXCR4-dependent Matrigel invasion. The mechanism by which LASP1 facilitates this invasive ability of tumor cells when CXCR4 is activated is unknown. Our previous proteomics work had revealed several components of the RNA interference (RNAi) machinery as being potential LASP1 interacting proteins. Here we report that argonaute 2 (Ago2), a protein with central involvement in RNAi, associates with LASP1 in triple-negative breast cancer (TNBC) cells. We demonstrate that LASP1 co-immunoprecipitates with Ago2 endogenously in a CXCL12-dependent manner, with further confirmation of this interaction by proximity ligation assay. Furthermore, this association is specific to CXCR4 as it can be abrogated by the CXCR4 antagonist, AMD3465. By GST-pulldown approach, we identify that LASP1 directly binds to Ago2 through its LIM and SH3 domains, and that this binding is dictated by the S146 and Y171 phosphorylation sites of LASP1. Additionally, the phosphorylation status of LASP1 affected tumor suppressor microRNA (miRNA) Let-7a-guided Ago2 activity. Levels of several endogenous targets of Let-7a were found to be altered including C-C chemokine receptor type 7 (CCR7), which is another critical chemokine receptor involved in metastasis to lymph nodes. Our results suggest a novel role for the LASP1-Ago2 module in shaping the RNAi landscape, functionally impacting the invasive ability of cancer cells.

Unique miRNA profiling of squamous cell carcinoma arising from ovarian mature teratoma: comprehensive miRNA sequence analysis of its molecular background

Owing to its rarity, the carcinogenesis and molecular biological characteristics of squamous cell carcinoma arising from mature teratoma remain unclear. This study aims to elucidate the molecular background of malignant transformation from the aspects of microRNA (miRNA) profiling. We examined 7 patients with squamous cell carcinoma and 20 patients with mature teratoma and extracted their total RNA from formalin-fixed paraffin-embedded tissues. Then we prepared small RNA libraries and performed comprehensive miRNA sequencing. Heatmap and principal component analysis revealed markedly different miRNA profiling in cancer, normal ovarian and mature teratoma tissues. Then we narrowed down cancer-related miRNAs, comparing paired-cancer and normal ovaries. Comparisons of cancer and mature teratoma identified two markedly upregulated miRNAs (miR-151a-3p and miR-378a-3p) and two markedly downregulated miRNAs (miR-26a-5p and miR-99a-5p). In addition, these findings were validated in fresh cancer tissues of patient-derived xenograft (PDX) models. Moreover, several miRNAs, including miR-151a-3p and miR-378a-3p, were elevated in the murine plasma when tumor tissues were enlarged although miR-26a-5p and miR-99a-5p were not elucidated in the murine plasma. Finally, we performed target prediction and functional annotation analysis in silico and indicated that targets genes of these miRNAs markedly correlated with cancer-related pathways, including 'pathway in cancer' and 'cell cycle'. In conclusion, this is the first study on miRNA sequencing for squamous cell carcinoma arising from mature teratoma. The study identified four cancer-related miRNAs that were considered to be related to the feature of malignant transformation. Moreover, miRNAs circulating in the murine plasma of the PDX model could be novel diagnostic biomarkers.

In situ miRNA delivery from a hydrogel promotes osteogenesis of encapsulated mesenchymal stromal cells

Hydrogels are attractive candidates for use in tissue-engineering and the encapsulation and subsequent differentiation of mesenchymal stem/stromal cells (MSCs) is a strategy that holds great promise for the repair and regeneration of bone and cartilage. However, MSCs are well-known for their sensitivity to mechanical cues, particularly substrate stiffness, and so the inherent softness of hydrogels is poorly matched to the mechanical cues that drive efficient osteogenesis. One approach to overcome this limitation is to harness mechanotransductive signalling pathways and override the signals cells receive from their environment. Previous reports demonstrate that mechanosensitive miRNAs, miR-100-5p and miR-143-3p can enhance MSC osteogenesis, using a complex multi-step procedure to transfect, encapsulate and differentiate the cells. In this study, we develop and characterise a facile system for in situ transfection of MSCs encapsulated within a light-crosslinkable gelatin-PEG hydrogel. Comparing the influence of different transfection agents and hydrogel compositions, we show that particle size, charge, and hydrogel mechanical properties all influence the diffusion of embedded transfection agent complexes. By incorporating both MSCs and transfection agents into the hydrogels we demonstrate successful in situ transfection of encapsulated MSCs. Comparing the efficacy of pre- and in situ transfection of miR-100-5p/miR-143-3p on the osteogenic capacity of hydrogel-encapsulated MSCs, our data demonstrates superior mineralisation and osteogenic gene expression following in situ transfections. Overall, we demonstrate a simple, one-pot system for in situ transfection of miRNAs to enhance MSC osteogenic potential and thus demonstrates significant promise to improve the efficiency of MSC differentiation in hydrogels for bone tissue-engineering applications. STATEMENT OF SIGNIFICANCE: Mesenchymal stromal cells (MSCs) are sensitive to cues from their surrounding microenvironment. Osteogenesis is enhanced in MSCs grown on stiffer substrates, but this is limited when using hydrogels for bone tissue-engineering. Modulating pro-osteogenic genes with mechanosensitive microRNAs (miRNAs) represents a potential tool to overcome this challenge. Here we report a hydrogel platform to deliver miRNAs to encapsulated MSCs. We characterise effects of hydrogel composition and transfection agent type on their mobility and transfection efficiency, demonstrating successful in situ transfection of MSCs and showing that miRNAs can significantly enhance osteogenic mineral deposition and marker gene expression. This system was simpler and more effective than conventional 2D transfection prior to encapsulation and therefore holds promise to improve MSC differentiation in bone tissue-engineering.

Roles of MicroRNAs in Esophageal Squamous Cell Carcinoma Pathogenesis

MicroRNAs (miRNAs) are 20-22 nucleotides long single-stranded noncoding RNAs. They regulate gene expression posttranscriptionally by base pairing with the complementary sequences in the 3'-untranslated region of their targeted mRNA. Aberrant expression of miRNAs leads to alterations in the expression of oncogenes and tumor suppressors, thereby affecting cellular growth, proliferation, apoptosis, motility, and invasion capacity of gastrointestinal cells, including cells of esophageal squamous cell carcinoma (ESCC). Thus, alterations in miRNAs expression associated with the pathogenesis and progression of ESCC. In addition, expression profiles of miRNAs correlated with various clinicopathological factors, including pathological stages, histological differentiation, invasion, metastasis of cancer, as well as survival rates and therapy response of patients with ESCC. Consequently, expression profiles of miRNAs could be useful as diagnostic, prognostic, and prediction biomarkers in ESCC. Herein, we describe the quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) and microarray methods for detection and quantitate miRNAs in ESCC. In addition, we summarize the roles of miRNAs in ESCC pathogenesis, progression, and prognosis.

miR-10a-5p and miR-29b-3p as Extracellular Vesicle-Associated Prostate Cancer Detection Markers

Extracellular vesicles (EVs) are shed by many different cell types. Their nucleic acids content offers new opportunities for biomarker research in different solid tumors. The role of EV RNA in prostate cancer (PCa) is still largely unknown. EVs were isolated from different benign and malignant prostate cell lines and blood plasma from patients with PCa (n = 18) and controls with benign prostatic hyperplasia (BPH) (n = 7). Nanoparticle tracking analysis (NTA), Western blot, electron microscopy, and flow cytometry analysis were used for the characterization of EVs. Non-coding RNA expression profiling of PC3 metastatic PCa cells and their EVs was performed by next generation sequencing (NGS). miRNAs differentially expressed in PC3 EVs were validated with qRT-PCR in EVs derived from additional cell lines and patient plasma and from matched tissue samples. 92 miRNAs were enriched and 48 miRNAs were depleted in PC3 EVs compared to PC3 cells, which could be confirmed by qRT-PCR. miR-99b-5p was significantly higher expressed in malignant compared to benign EVs. Furthermore, expression profiling showed miR-10a-5p (p = 0.018) and miR-29b-3p (p = 0.002), but not miR-99b-5p, to be overexpressed in plasma-derived EVs from patients with PCa compared with controls. In the corresponding tissue samples, no significant differences in the miRNA expression could be observed. We thus propose that EV-associated miR-10a-5p and miR-29b-3p could serve as potential new PCa detection markers.

Emerging roles of microRNAs in regulating the mTOR signaling pathway during tumorigenesis

The mammalian target of rapamycin (mTOR) is a large Ser/Thr protein kinase that belongs to the phosphoinositide 3-kinase (PI3K) family and mediates various physiological and pathological processes, especially cell proliferation, protein synthesis, autophagy, and cancer development. The mTOR expression is transient and tightly regulated in normal cells, but it is overactivated in cancer cells. Recently, several studies have indicated that microRNAs (miRNAs) play a critical role in the regulation of mTOR and mTOR-associated processes, some acting as inhibitors and the others as activators. Although it is still in infancy, the strategy of combining both miRNAs and mTOR inhibitors might provide an approach to selectively sensitizing tumor cells to chemotherapy-induced DNA damage and subsequently attenuating the tumor cell growth and apoptosis.

Discovery of MicroRNAs from Batrachuperus yenyuanensis Using Deep Sequencing and Prediction of Their Targets

MicroRNAs (miRNAs), a family of ∼22-nucleotide non-coding single-stranded RNA molecules, are considered as key post-transcriptional regulators of gene expression that regulate various biological processes in living organism. Many miRNAs have been identified in animals; however, few have been reported in Hynobiidae species. The present study is aimed to identify a full repertoire of miRNAs in Batrachuperus yenyuanensis (Yenyuan stream salamander), which would significantly increase our knowledge of miRNAs in amphibians. A small RNA library was constructed from B. yenyuanensis and sequenced using deep sequencing. As a result, 1,717,751 clean reads were obtained, representing 356 known and 80 novel miRNAs. Additionally, expression levels of eight randomly selected miRNAs in B. yenyuanensis were confirmed using the stem-loop quantitative real-time reverse transcription PCR. In addition, 13,972 targets were predicted for these identified miRNAs, although the physiological functions of many of these targets remain unknown. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis suggested that the predicted targets are involved in a variety of physiological regulatory functions in B. yenyuanensis. These results provide useful information for further research on the miRNAs involved in the growth and development of B. yenyuanensis, as well as adaptation of this species to its high-altitude habitats.

hsa_circ_0006168 sponges miR-100 and regulates mTOR to promote the proliferation, migration and invasion of esophageal squamous cell carcinoma

Circle RNAs (circRNAs) are the novel noncoding RNAs with the covalent closed-loop structure, which play a crucial role in a variety of pathological processes, including cancer. Nevertheless, the expression profiles and functions of circRNAs in esophageal squamous cell cancer (ESCC) remain largely unknown. In this paper, 10 pairs of ESCC tissues were utilized to screen the circRNA expression profiles by means of microarray assay; further, a novel circular RNA named hsa_circ_0006168 was investigated. Meanwhile, the expression of hsa_circ_0006168 was measured in 52 ESCC tissues and in cell lines. Our results suggested that, hsa_circ_0006168 was remarkably increased not only in ESCC tissues but also in cell lines compared with those in normal cases. Besides, high hsa_circ_0006168 expression was positively connected with lymph node metastasis and TNM stage of ESCC patients. In vitro, the proliferation, invasion and migration capacities of ESCC cells were suppressed through down-regulating hsa_circ_0006168 expression. Besides, RNase R digestion assay confirmed that hsa_circ_0006168 was more stable than its linear CNOT6L mRNA form. Moreover, nuclear and cytoplasmic fraction assay indicated that hsa_circ_0006168 was mainly distributed in the cytoplasm of Kyse450 and TE13 cells. Mechanically, it was discovered in this study that hsa_circ_0006168 might regulate the expression of Mammalian Target of Rapamycin (mTOR) by sponging microRNA-100 (miR-100). Taken together, hsa_circ_0006168 can promote ESCC proliferation, migration and invasion through the competing endogenous RNA (ceRNA) mechanism, which has been first confirmed in our results. In ESCC, hsa_circ_0006168 can serve as a potential diagnostic biomarker and therapeutic target.

Enhanced Inhibition of Tumorigenesis Using Combinations of miRNA-Targeted Therapeutics

The search for effective strategies to inhibit tumorigenesis remains one of the most relevant scientific challenges. Among the most promising approaches is the direct modulation of the function of short non-coding RNAs, particularly miRNAs. These molecules are propitious targets for anticancer therapy, since they perform key regulatory roles in a variety of signaling cascades related to cell proliferation, apoptosis, migration, and invasion. The development of pathological states is often associated with deregulation of miRNA expression. The present review describes in detail the strategies aimed at modulating miRNA activity that invoke antisense oligonucleotide construction, such as small RNA zippers, miRNases (miRNA-targeted artificial ribonucleases), miRNA sponges, miRNA masks, anti-miRNA oligonucleotides, and synthetic miRNA mimics. The broad impact of developed miRNA-based therapeutics on the various events of tumorigenesis is also discussed. Above all, the focus of this review is to evaluate the results of the combined application of different miRNA-based agents and chemotherapeutic drugs for the inhibition of tumor development. Many studies indicate a considerable increase in the efficacy of anticancer therapy as a result of additive or synergistic effects of simultaneously applied therapies. Different drug combinations, such as a cocktail of antisense oligonucleotides or multipotent miRNA sponges directed at several oncogenic microRNAs belonging to the same/different miRNA families, a mixture of anti-miRNA oligonucleotides and cytostatic drugs, and a combination of synthetic miRNA mimics, have a more complex and profound effect on the various events of tumorigenesis as compared with treatment with a single miRNA-based agent or chemotherapeutic drug. These data provide strong evidence that the simultaneous application of several distinct strategies aimed at suppressing different cellular processes linked to tumorigenesis is a promising approach for cancer therapy.

Micromanaging aerobic respiration and glycolysis in cancer cells

BACKGROUND

Cancer cells possess a common metabolic phenotype, rewiring their metabolic pathways from mitochondrial oxidative phosphorylation to aerobic glycolysis and anabolic circuits, to support the energetic and biosynthetic requirements of continuous proliferation and migration. While, over the past decade, molecular and cellular studies have clearly highlighted the association of oncogenes and tumor suppressors with cancer-associated glycolysis, more recent attention has focused on the role of microRNAs (miRNAs) in mediating this metabolic shift. Accumulating studies have connected aberrant expression of miRNAs with direct and indirect regulation of aerobic glycolysis and associated pathways.

SCOPE OF REVIEW

This review discusses the underlying mechanisms of metabolic reprogramming in cancer cells and provides arguments that the earlier paradigm of cancer glycolysis needs to be updated to a broader concept, which involves interconnecting biological pathways that include miRNA-mediated regulation of metabolism. For these reasons and in light of recent knowledge, we illustrate the relationships between metabolic pathways in cancer cells. We further summarize our current understanding of the interplay between miRNAs and these metabolic pathways. This review aims to highlight important metabolism-associated molecular components in the hunt for selective preventive and therapeutic treatments.

MAJOR CONCLUSIONS

Metabolism in cancer cells is influenced by driver mutations but is also regulated by posttranscriptional gene silencing. Understanding the nuanced regulation of gene expression in these cells and distinguishing rapid cellular responses from chronic adaptive mechanisms provides a basis for rational drug design and novel therapeutic strategies.

Comprehensive Profiling of the Circulatory miRNAome Response to a High Protein Diet in Elderly Men: A Potential Role in Inflammatory Response Modulation

SCOPE

MicroRNA are critical to the coordinated post-transcriptional regulation of gene expression, yet few studies have addressed the influence of habitual diet on microRNA expression. High protein diets impact cardiometabolic health and body composition in the elderly suggesting the possibility of a complex systems response. Therefore, high-throughput small RNA sequencing technology is applied in response to doubling the protein recommended dietary allowance (RDA) over 10 weeks in older men to examine alterations in circulating miRNAome.

METHODS AND RESULTS

Older men (n = 31; 74.1 ± 0.6 y) are randomized to consume either RDA (0.8 g kg^-1  day^-1 ) or 2RDA (1.6 g kg^-1  day^-1 ) of protein for 10 weeks. Downregulation of five microRNAs (miR-125b-5p, -100-5p, -99a-5p, -23b-3p, and -203a) is observed following 2RDA with no changes in the RDA. In silico functional analysis highlights target gene enrichment in inflammation-related pathways. qPCR quantification of predicted inflammatory genes (TNFα, IL-8, IL-6, pTEN, PPP1CB, and HOXA1) in peripheral blood mononuclear cells shows increased expression following 2RDA diet (p ≤ 0.05).

CONCLUSION

The study findings suggest a possible selective alteration in the post-transcriptional regulation of the immune system following a high protein diet. However, very few microRNAs are altered despite a large change in the dietary protein.

Comprehensive analysis of dysregulated lncRNAs, miRNAs and mRNAs with associated ceRNA network in esophageal squamous cell carcinoma

Mounting evidence suggests that long noncoding RNAs (lncRNAs) play an important role in tumor biology. To date, some lncRNAs have been found to be involved in competitive binding of miRNAs, a major group of competitive endogenous RNAs (ceRNAs), through participation in a regulatory network of protein-coding gene expression. However, the functional roles of lncRNA-mediated ceRNAs in esophageal squamous cell carcinoma (ESCC) have rarely been reported. Here, we construct a hypothetical ceRNA network by analyzing differential expression of lncRNAs, miRNAs and mRNAs obtained from 96 ESCC tissues and 13 normal tissues in the Cancer Genome Atlas. Ultimately, 95 lncRNAs, 9 miRNAs, and 40 mRNAs were identified (fold change >1.5, P < .05) and included in the ceRNA network for ESCC. Moreover, three lncRNAs (IGF2-AS, MUC2 and SOX2-OT) were found to be significantly associated with overall survival (log-rank test, P < .05), and further experiments revealed that lncRNA DLX6-AS1 knockdown inhibited the proliferation and invasion of esophageal cancer cells by enhancing the endogenous function of mTOR. We believe that the identified ceRNA network can facilitate a better understanding of lncRNA-related mechanisms in ESCC.

Upregulation of microRNA‑194‑5p inhibits hypopharyngeal carcinoma cell proliferation, migration and invasion by targeting SMURF1 via the mTOR signaling pathway

Hypopharyngeal carcinoma (HPC) is an aggressive malignancy with the worst prognosis among all head and neck cancers. MicroRNAs (miRNAs) are involved in the development of many human cancers, and may function as oncogenes or tumor suppressors. The present study aimed to evaluate the effects of miRNA (miR)-194-5p on the proliferation and invasion of HPC cells and to identify the potential regulatory mechanism. First, miR-194-5p and Smad ubiquitin regulatory factor 1 (SMURF1) expression levels were examined in HPC tissues. Subsequently, to explore the effects of miR-194-5p on SMURF1, a dual-luciferase reporter gene assay was performed to verify the target relationship. To define the role of miR-194-5p in HPC progression, miR-194-5p upregulation and depletion were used to evaluate its effects on cell viability, invasion and migration. SMURF1 silencing and rapamycin [an inhibitor of the mammalian target of rapamycin (mTOR) signaling pathway] treatment were also used to analyze the regulatory mechanism in HPC. Finally, tumor growth was assessed in xenografted tumors in nude mice. SMURF1 was demonstrated to be highly expressed, whereas miR-194-5p was poorly expressed in HPC tissues; SMURF1 was identified as a target gene of miR-194-5p. FaDu hypopharyngeal squamous cell carcinoma cells treated with miR-194-5p mimics exhibited decreased viability, invasion and migration. The results indicated that miR-194-5p may inactivate the mTOR signaling pathway by targeting SMURF1. In addition, the in vivo experiments further verified these regulatory effects. These data suggested that miR-194-5p-targeted SMURF1 inhibition may be involved in the disruption of HPC progression through the repression of the mTOR signaling pathway.

miR-125b-5p and miR-99a-5p downregulate human γδ T-cell activation and cytotoxicity

As an important component of innate immunity, human circulating γδ T cells function in rapid responses to infections and tumorigenesis. MicroRNAs (miRNAs) play a critical regulatory role in multiple biological processes and diseases. Therefore, how the functions of circulating human γδ T cells are regulated by miRNAs merits investigation. In this study, we profiled the miRNA expression patterns in human peripheral γδ T cells from 21 healthy donors and identified 14 miRNAs that were differentially expressed between peripheral αβ T cells and γδ T cells. Of the 14 identified genes, 7 miRNAs were downregulated, including miR-150-5p, miR-450a-5p, miR-193b-3p, miR-365a-3p, miR-31-5p, miR-125b-5p and miR-99a-5p, whereas the other 7 miRNAs were upregulated, including miR-34a-5p, miR-16-5p, miR-15b-5p, miR-24-3p, miR-22-3p, miR-22-5p and miR-9-5p, in γδ T cells compared with αβ T cells. In subsequent functional studies, we found that both miR-125b-5p and miR-99a-5p downregulated γδ T cell activation and cytotoxicity to tumor cells. Overexpression of miR-125b-5p or miR-99a-5p in γδ T cells inhibited γδ T cell activation and promoted γδ T cell apoptosis. Additionally, miR-125b-5p knockdown facilitated the cytotoxicity of γδ T cells toward tumor cells in vitro by increasing degranulation and secretion of IFN-γ and TNF-α. Our findings improve the understanding of the regulatory functions of miRNAs in γδ T cell activation and cytotoxicity, which has implications for interventional approaches to γδ T cell-mediated cancer therapy.

An integrated framework for the identification of potential miRNA-disease association based on novel negative samples extraction strategy

MicroRNAs (miRNAs) play an important role in prevention, diagnosis and treatment of human complex diseases. Predicting potential miRNA-disease associations could provide important prior information for medical researchers. Therefore, reliable computational models are expected to be an effective supplement for inferring associations between miRNAs and diseases. In this study, we developed a novel calculative model named Negative Samples Extraction based MiRNA-Disease Association prediction (NSEMDA). NSEMDA filtered reliable negative samples by two positive-unlabeled learning models, namely, the Spy and Rocchio techniques and calculated similarity weights for ambiguous samples. The positive samples, reliable negative samples and ambiguous samples with similarity weights were used to construct a Support Vector Machine-Similarity Weight model to predict miRNA-disease associations. NSEMDA improved the credibility of negative samples and reduced the impact of noise samples by introducing ambiguous samples with similarity weights to train prediction model. As a result, NSEMDA achieved the AUC of 0.8899 in global leave-one-out cross validation (LOOCV) and AUC of 0.8353 under local LOOCV. In 100 times 5-fold cross validation, NSEMDA obtained an average AUC of 0.8878 and standard deviation of 0.0014. These AUCs are higher than many classical models. Besides, we also carried out three kinds of case studies to evaluate the performance of NSEMDA. Among the top 50 potential related miRNAs of esophageal neoplasms, lung neoplasms and carcinoma hepatocellular predicted by NSEMDA, 46, 50 and 45 miRNAs were verified to be associated with the investigated disease by experimental evidences, respectively. Therefore, NSEMDA would be a reliable calculative model for inferring miRNA-disease associations.

miR-92b-3p-TSC1 axis is critical for mTOR signaling-mediated vascular smooth muscle cell proliferation induced by hypoxia

Pulmonary artery smooth muscle cells (PASMCs) undergo proliferation by the mammalian target of rapamycin (mTOR) signaling pathway under hypoxia. Hypoxia induces expression of a specific set of microRNAs (miRNAs) in a variety of cell types. We integrated genomic analyses of both small non-coding RNA and coding transcripts using next-generation sequencing (NGS)-based RNA sequencing with the molecular mechanism of the mTOR signaling pathway in hypoxic PASMCs. These analyses revealed hypoxia-induced miR-92b-3p as a potent regulator of the mTOR signaling pathway. We demonstrated that miR-92b-3p directly targets the 3′-UTR of a negative regulator in the mTOR signaling pathway, TSC1. mTOR signaling and consequent cell proliferation were promoted by enforced expression of miR-92b-3p but inhibited by knocking down endogenous miR-92b-3p. Furthermore, inhibition of miR-92b-3p attenuated hypoxia-induced proliferation of vascular smooth muscle cells (VSMCs). Therefore, this study elucidates a novel role of miR-92b-3p as a hypoxamir in the regulation of the mTOR signaling pathway and the pathological VSMC proliferative response under hypoxia. These findings will help us better understand the miRNA-mediated molecular mechanism of the proliferative response of hypoxic VSMCs through the mTOR signaling pathway.

Prognostic Value of MicroRNAs in Esophageal Carcinoma: A Meta-Analysis

Background

Numerous articles have reported that abnormal expression levels of microRNAs (miRNAs) are related to the survival times of esophageal carcinoma (EC) patients, which contains esophageal adenocarcinoma (EAC) and esophageal squamous cell carcinoma (ESCC). Nevertheless, there has not been a comprehensive meta-analysis to assess the accurate prognostic value of miRNAs in EC.

Methods

Studies published in English up to April 12, 2018 that evaluated the correlation of the expression levels of miRNAs with overall survival (OS) in EC were identified by online searches in PubMed, EMBASE, Web of Science, and the Cochrane Database of Systematic Reviews performed by two independent authors. The pooled hazard ratios (HRs) with 95% confidence intervals (CIs) were used to estimate the correlation between OS and miRNA expression. HR ≥ 2 was considered cutoff for considering the miRNA as prognostic candidate.

Results

Forty-four pertinent articles with 22 miRNAs and 4310 EC patients were ultimately included. EC patients with tissue expression levels of high miR-21 or low miR-133a (HR = 2.48, 95% CI = 1.50–4.12), miR-133b (HR = 2.15, 95% CI = 1.27–3.62), miR-138 (HR = 2.27, 95% CI = 1.68–3.08), miR-203 (HR = 2.83, 95% CI = 1.35–5.95), miR-375 and miR-655 (HR = 2.66, 95% CI = 1.16–6.12) had significantly poorer OS (P < 0.05). In addition, EC patients with blood expression levels of high miR-21 (HR = 2.19, 95% CI = 1.31–3.68) and miR-223 had significantly shorter OS (P < 0.05).

Conclusions

In conclusion, tissue expression levels of miR-21, miR-133a, miR-133b, miR-138, miR-203, miR-375, and miR-655 and blood expression levels of miR-21 and miR-223 demonstrate significant prognostic value. Among them, the expression levels of miR-133a, miR-133b, miR-138, miR-203, and miR-655 in tissue and the expression level of miR-21 in blood are potential prognostic candidates for predicting OS in EC.

High miR-100 expression is associated with aggressive features and modulates TORC1 complex activation in lung carcinoids

PURPOSE

Mammalian target of rapamycin (mTOR) is a promising therapeutic target in advanced lung carcinoid patients. However, the mechanisms of mTOR modulation and of responsiveness to mTOR inhibitors are largely unclear. Our aim was to analyze the expression and functional role of specific miRNAs in lung carcinoids as an alternative mechanism targeting mTOR pathway.

EXPERIMENTAL DESIGN

Seven miRNAs, selected by bioinformatic tools and literature search, were analyzed in 142 lung neuroendocrine neoplasms (92 carcinoids and a control group of 50 high grade neuroendocrine carcinomas), and compared with mTOR mRNA expression and clinical/pathological parameters. Tissue results were validated in vitro in two lung carcinoid cell lines by specific RNA interference and biological/pharmacological tests.

RESULTS

Tissutal expression of five miRNAs (miR-99b, miR-100, miR-155, miR-193a-3p, miR-193a-5p) was inversely correlated with mTOR mRNA expression, supporting their role in the negative regulation of mTOR transcription. High expression of miR-100, miR-193a-3p and miR-193a-5p was associated with aggressive features and, for the former two, with shorter time to progression. In H727 and UMC11 lung carcinoid cells, miR-100 modulated mTOR RNA and TORC1 complex protein expression, positively promoted cell migration and negatively influenced cell proliferation. Moreover, miR-100 directly influenced responsiveness of H727 and UMC11 cells to rapamycin.

CONCLUSIONS

MiR-100 actively participates to the regulation of mTOR expression in lung carcinoids and represents a novel candidate prognostic biomarker for this tumor type; moreover, inhibition of its expression is associated to increased responsiveness to mTOR inhibitors and might represent a novel strategy to sensitize lung carcinoids to these target agents.

Co-targeting of IGF1R/mTOR pathway by miR-497 and miR-99a impairs hepatocellular carcinoma development

Persistent activation of IGF1R/mTOR signaling pathway plays crucial role in the development of hepatocellular carcinoma (HCC). Therefore, our goal was to elucidate microRNAs (miRNAs) targeting IGF1R/mTOR and the therapeutic potential of single or dual miRNA on HCC development. In this study, we found that miR-497 and miR-99a that target the 3′-UTR of both IGF1R and mTOR were down-regulated in HCC human tissues and cell lines. Functional assay revealed that ectopic expression of miR-497 or miR-99a in HCC cells resulted in a significant inhibition on tumor growth and invasiveness in vitro and tumor development in vivo via repressing the expression of IGF1R and mTOR. Such inhibitory effect on tumor growth is reversed by application of IGF1 ((IGF1R ligand) or MHY1485 (mTOR agonist) in vitro. Furthermore, we found that simultaneous over-expression of both miR-497 and miR-99a exhibited much stronger inhibitory effects on tumor growth than their individual effect, which is still correlated with significantly stronger repression of IGF1R and mTOR. Overall, our results suggest that miR-497 and miR-99a both function as tumor-suppressive miRNAs by suppressing IGF1R/mTOR signaling pathway. The synergistic actions of these two miRNAs partly correlated with IGF1R and mTOR levels, which may represent new strategies for the molecular treatment of HCC.

MicroRNAs in esophageal squamous cell carcinoma: Potential biomarkers and therapeutic targets

Esophageal cancer is a common cause of cancer-related deaths worldwide. Squamous cell carcinoma (SCC) is the major histological type of esophageal cancer in developing countries including China, and the prognosis is very poor. Many microRNAs are involved in several important biological and pathologic processes, and promote tumorigenesis. To better understand the prognostic and therapeutic roles of microRNAs in ESCC, we reviewed the diagnosis and prognosis associated oncogenic microRNAs (e.g. miR-21 and miR-17-92 cluster) and tumor suppressor microRNAs (e.g. miR-375, miR-133a and miR-133b), and diagnosis and prognosis associated oncogenic target genes (e.g. PDCD4 and CCND1) and tumor suppressor target genes (e.g. EZH2 and PDK1). We also summarized the prognostic microRNA and target gene pairs (e.g. miR-296 and CCND1, miR214 and EZH2). Taken together, our review highlights the opportunities and challenges for microRNAs in the molecular diagnosis and target therapy of ESCC.

Mechanically-sensitive miRNAs bias human mesenchymal stem cell fate via mTOR signalling

Mechanotransduction is a strong driver of mesenchymal stem cell (MSC) fate. In vitro, variations in matrix mechanics invoke changes in MSC proliferation, migration and differentiation. However, when incorporating MSCs within injectable, inherently soft hydrogels, this dominance over MSC response substantially limits our ability to couple the ease of application of hydrogels with efficiently directed MSC differentiation, especially in the case of bone generation. Here, we identify differential miRNA expression in response to varying hydrogel stiffness and RhoA activity. We show that modulation of miR-100-5p and miR-143-3p can be used to bias MSC fate and provide mechanistic insight by demonstrating convergence on mTOR signalling. By modulating these mechanosensitive miRNAs, we can enhance osteogenesis in a soft 3D hydrogel. The outcomes of this study provide new understanding of the mechanisms regulating MSC mechanotransduction and differentiation, but also a novel strategy with which to drive MSC fate and significantly impact MSC-based tissue-engineering applications.

Mesenchymal stem cell (MSC) fate can be mechanically regulated by substrate stiffness but this is difficult to control in a 3D hydrogel. Here the authors identify miRNAs that change expression in response to substrate stiffness and RhoA signalling and show that they can bias MSC fate in a 3D soft hydrogel.

miR-99a-5p acts as tumor suppressor via targeting to mTOR and enhances RAD001-induced apoptosis in human urinary bladder urothelial carcinoma cells

Introduction

miR-99a-5p, known to play an important role in mammalian target of rapamycin (mTOR) regulation, is downregulated in human bladder cancer. The study aimed to investigate the anticancer activity of miR-99a-5p and the possible mechanism associated with mTOR in bladder cancer cells.

Materials and methods

Vectors expressing miR-99a-5p were transfected into human urinary bladder urothelial carcinoma (5637 and T24) cells. The level of miR-99a-5p was monitored by microRNA (miRNA) quantitative polymerase chain reaction (QPCR). Luciferase reporter assays were performed to verify the direct binding of miR-99a-5p to mTOR transcripts. The mTOR transcripts and protein levels were measured by QPCR and Western blot, respectively. Cell viability of miR-99a-5p-transfected cells was detected by tetrazolium salt (WST-1). Inhibition of mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2) signaling was detected by the phosphorylation of mTOR and AKT using Western blot. The ability of miR-99a-5p to enhance RAD001-induced apoptosis was determined as the expression of cleaved caspase 3 and levels of DNA fragmentation.

Results

Transfection of miR-99a-5p-expressing vector elevated the expression level of miR-99a-5p up to sixfold compared to vector-only controls. The results from luciferase assay verified that miR-99a-5p directly binds to the predicted sequence in the 3′ untranslated region (3′-UTR) of mTOR. The levels of mTOR RNA and protein were decreased in miR-99a-5p-transfected cells. Dual inhibition of mTORC1 and mTORC2 by miR-99a-5p was confirmed by the decreased phosphorylation of mTOR (at Ser2448 and Ser2481), phospho-rpS6 and phospho-4EBP1. The phosphorylation of AKT was significantly inhibited in miR-99a-5p-transfected cells upon RAD001 treatment. Enforced expression of miR-99a-5p potentiated RAD001-induced apoptosis in these cells.

Conclusion

This is the first study showing that miR-99a-5p markedly inhibits the growth of bladder cancer cells via dual inhibition of mTORC1 and mTORC2. Our data demonstrated that forced expression of miR-99a-5p inhibits the feedback of AKT survival pathway and enhances the induction of apoptosis in RAD001-treated bladder cancer cells.

Pooling-analysis for diagnostic and prognostic value of MiRNA-100 in various cancers

Many studies manifested miRNA-100 was deregulated in various cancers, which indicated that miRNA-100 might be a potential biomarker of cancer diagnosis and prognosis. However, the role of miRNA-100 was still uncertain. We searched for qualified studies using PubMed, EMBASE, Web of Science, Cochrane library and CNKI databases. The diagnostic effect was evaluated by the pooled sensitivity, specificity, and other indexes. Pooled hazard ratios (HRs) with 95% confidence intervals (CIs) for overall survival (OS) were calculated to assess the prognostic value. This meta-analysis included 7 and 19 studies about diagnosis and prognosis, respectively. The results of pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR) and diagnostic odds ratio (DOR) were 0.75 (95%CI: 0.71-0.78), 0.74 (95%CI: 0.69-0.78), 2.61 (95%CI: 1.81-3.76), 0.33 (95%CI: 0.24-0.45), 8.46 (95%CI: 4.85-14.77), respectively. And, the area under SROC curve (AUC) was 0.8141. We also found that lower expression of miRNA-100 in cancer tissues could significantly predict poorer prognosis in overall cancer (HR = 0.59, 95%CI: 0.39-0.90), especially in genital system tumors (HR = 0.42, 95%CI: 0.27-0.66, P = 0.431), bladder cancer (HR = 0.21, 95%CI: 0.06-0.73, P = 0.143) and esophageal squamous cell carcinoma (HR = 0.26, 95%CI: 0.13-0.52, P = 0.164). Our studies concluded that miRNA-100 has a certain value in diagnosis and it may indicate a poor prognosis of cancers.

Molecular profiling of locally-advanced rectal adenocarcinoma using microRNA expression (Review)

Treatment for locally-advanced rectal cancer (LARC) typically consists of neoadjuvant chemoradiation followed by total mesorectal excision. Recently, there has been growing interest in non-operative management for patients who are medically-inoperable or wish to avoid surgical morbidity and permanent colostomy. Approximately 50% of patients who receive pre-operative neoadjuvant chemoradiation develop some degree of pathologic response. Approximately 10-20% of patients are found to have a complete pathologic response, a finding which has frequently been shown to predict better clinical outcomes, including local-regional control, distant metastasis and survival. Many recent studies have evaluated the role of molecular biomarkers in predicting response to neoadjuvant therapy. MicroRNAs (miRNAs) are an emerging class of biomarkers that have the potential to predict which patients are most likely to benefit from pre-operative therapy and from a selective surgical approach. Here, we review the published literature on microRNAs as prognostic and predictive biomarkers in rectal cancer after pre-operative therapy. In the future, the development of prospectively validated miRNA signatures will allow clinical implementation of miRNAs as prognostic and predictive signatures in LARC.

microRNA-99a Reduces Lipopolysaccharide-Induced Oxidative Injury by Activating Notch Pathway in H9c2 Cells

microRNA-99a (miR-99a) is recently recognized as a key regulator in various cancers and cardiovascular diseases. In the present study, we sought to investigate the effects of miR-99a in rat cardiomyocyte H9c2 cells against oxidative injury induced by lipopolysaccharide (LPS).MTT assay, reactive oxygen species (ROS) assay, flow cytometry and lactate dehydrogenase (LDH) assay were respectively used to explore viability, ROS levels, apoptosis, and cell death in H9c2 cells. Quantitative PCR (qRT-PCR) was performed to confirm the expression of miR-99a. Western blot was performed to determine the expression of Notch pathway factors.LPS could significantly suppress viability and increase cell death, apoptosis, and ROS level (P < 0.05). However, miR-99a could significantly increase the viability and decrease apoptosis and ROS level of H9c2 cells (P < 0.05). Overexpression of miR-99a could activate a Notch pathway and regulate the expression of B-cell CLL/lymphoma 2 (BCL2) and cleaved caspase 3.Our study found that overexpression of miR-99a could attenuate LPS-induced oxidative injury in H9c2 cells, possibly via a Notch pathway. These findings suggest that miR-99a may be a key factor in cardiomyocyte oxidative injury and could be a new therapeutic strategy for cardiovascular diseases.

Emerging Role of MicroRNAs in mTOR Signaling

Mechanistic target of rapamycin (mTOR) is a conserved serine/threonine kinase that plays a critical role in the control of cellular growth and metabolism. Hyperactivation of mTOR pathway is common in human cancers, driving uncontrolled proliferation. MicroRNA (miRNA) is a class of short noncoding RNAs that regulate the expression of a wide variety of genes. Deregulation of miRNAs is a hallmark of cancer. Recent studies have revealed interplays between miRNAs and the mTOR pathway during cancer development. Such interactions appear to provide a fine-tuning of various cellular functions and contribute qualitatively to the behavior of cancer. Here we provide an overview of current knowledge regarding the reciprocal relationship between miRNAs and mTOR pathway: regulation of mTOR signaling by miRNAs and control of miRNA biogenesis by mTOR. Further research in this area may prove important for the diagnosis and therapy of human cancer.

Prognostic significance of microRNA-100 in solid tumors: an updated meta-analysis

Objective

The aim of this study was to identify prognostic significance of microRNA-100 (miR-100) in solid tumor.

Methods

Literature search was conducted in databases such as PubMed, Embase, and Web of Science, using the following words “(microRNA-100 OR miR-100 OR mir100) AND (tumor OR neoplasm OR cancer OR carcinoma OR malignancy).” The search was updated up until July 10, 2016. Newcastle–Ottawa scale was used to evaluate the quality of studies. Pooled hazard ratio (HR) with 95% confidence interval (CI) for patients’ survival was calculated by using a fixed-effects or a random-effects model on the basis of heterogeneity. Subgroup analysis, sensitive analysis, and meta-regression were used to investigate the sources of heterogeneity. Publication bias was evaluated by using Begg’s and Egger’s tests.

Results

A total of 16 articles with 1,501 patients were included in the present meta-analysis. It was demonstrated that a lower expression of miR-100 plays a negative role in the overall survival (OS) of patients with solid tumor (HR =1.92; 95% CI =1.25–2.94). In addition, the association between miR-100 and prognosis was also revealed in the following subgroups: non-small-cell lung cancer (NSCLC; HR =2.46; 95% CI =1.98–3.06), epithelial ovarian cancer (EOC; HR =2.29, 95% CI =1.72–3.04), and bladder cancer (BC; HR =4.14, 95% CI =1.85–9.27).

Conclusion

This meta-analysis indicates that lower expression of miR-100 is related to poorer OS in patients with solid tumor, especially in those with NSCLC, EOC, and BC. MiR-100 is a promising prognosis predictor and may be a potential target for therapy in the future.

MicroRNA 100 sensitizes luminal A breast cancer cells to paclitaxel treatment in part by targeting mTOR

Luminal A breast cancer usually responds to hormonal therapies but does not benefit from chemotherapies, including microtubule-targeted paclitaxel. MicroRNAs could play a role in mediating this differential response. In this study, we examined the role of micro RNA 100 (miR-100) in the sensitivity of breast cancer to paclitaxel treatment. We found that while miR-100 was downregulated in both human breast cancer primary tumors and cell lines, the degree of downregulation was greater in the luminal A subtype than in other subtypes. The IC₅₀ of paclitaxel was much higher in luminal A than in basal-like breast cancer cell lines. Ectopic miR-100 expression in the MCF-7 luminal A cell line enhanced the effect of paclitaxel on cell cycle arrest, multinucleation, and apoptosis, while knockdown of miR-100 in the MDA-MB-231 basal-like line compromised these effects. Similarly, overexpression of miR-100 enhanced the effects of paclitaxel on tumorigenesis in MCF-7 cells. Rapamycin-mediated inhibition of the mammalian target of rapamycin (mTOR), a target of miR-100, also sensitized MCF-7 cells to paclitaxel. Gene set enrichment analysis showed that genes that are part of the known paclitaxel-sensitive signature had a significant expression correlation with miR-100 in breast cancer samples. In addition, patients with lower levels of miR-100 expression had worse overall survival. These results suggest that miR-100 plays a causal role in determining the sensitivity of breast cancers to paclitaxel treatment.

The role of microRNA in esophageal squamous cell carcinoma

MicroRNAs (miRNA) are 22-nucleotide non-coding RNAs that post-transcriptionally regulate gene expression by base pairing to partially complementary sequences in the 3'-untranslated region of their target messenger RNA. Altered miRNA expression also changes the expression of oncogenes and tumor suppressors, affecting the proliferation, apoptosis, motility and invasibility of gastrointestinal cancer cells, including the cells of esophageal squamous cell carcinoma (ESCC). It has been suggested that various miRNA expression profiles may provide useful biomarkers and therapeutic targets, but to date few studies have been published on the role of miRNA in ESCC. In this review we summarize the identification and characterization of miRNAs involved in ESCC and discuss their potential as biomarkers and therapeutic targets.

Sirolimus and Everolimus Pathway: Reviewing Candidate Genes Influencing Their Intracellular Effects

Sirolimus (SRL) and everolimus (EVR) are mammalian targets of rapamycin inhibitors (mTOR-I) largely employed in renal transplantation and oncology as immunosuppressive/antiproliferative agents. SRL was the first mTOR-I produced by the bacterium Streptomyces hygroscopicus and approved for several medical purposes. EVR, derived from SRL, contains a 2-hydroxy-ethyl chain in the 40th position that makes the drug more hydrophilic than SRL and increases oral bioavailability. Their main mechanism of action is the inhibition of the mTOR complex 1 and the regulation of factors involved in a several crucial cellular functions including: protein synthesis, regulation of angiogenesis, lipid biosynthesis, mitochondrial biogenesis and function, cell cycle, and autophagy. Most of the proteins/enzymes belonging to the aforementioned biological processes are encoded by numerous and tightly regulated genes. However, at the moment, the polygenic influence on SRL/EVR cellular effects is still not completely defined, and its comprehension represents a key challenge for researchers. Therefore, to obtain a complete picture of the cellular network connected to SRL/EVR, we decided to review major evidences available in the literature regarding the genetic influence on mTOR-I biology/pharmacology and to build, for the first time, a useful and specific “SRL/EVR genes-focused pathway”, possibly employable as a starting point for future in-depth research projects.

The Pleiotropic Effects of miRNAs on Tumor Angiogenesis

Angiogenesis, the process of new blood vessel formation and growth from already existing venules is critical in vascular development and homeostasis controlled by the balance of pro- and anti-angiogenic factors. Emerging evidence indicates the development, progression, and metastasis of various human cancers are strongly relied on angiogenesis. However, molecular mechanisms that underlie the complex regulation of angiogenic processes are still not fully elucidated. Recent studies revealed that microRNAs (miRNAs) were important regulators of tumor angiogenesis and the entire research in this area has entered into a so-called "miRNAs era." Thus, miRNAs might be important therapeutic targets or biomarkers for cancer. Due to the complexity of miRNA regulating mechanisms, how specific miRNAs intersect with and modulate tumor angiogenesis is still unclear. The conflicting results of the same miRNAs from different groups indicated that miRNAs might possess potent activity in a cell type or cell context specific manner. Here, we present a summary of latest advances in understanding the roles of angiogenic miRNAs as potential tools or targets in cancer therapy.